Cancel syncs for calendar, tasks, and contacts separately

* Disable pending sync indicator on Android 14+

* Disable forever pending sync workaround on Android 14+

.github/dependabot.yml

@@ -8,4 +8,7 @@ updates:
     schedule:
       interval: "weekly"
     commit-message:
-      prefix: "[CI] "
+      prefix: "[CI] "
+    groups:
+      ci-actions:
+        patterns: ["*"]

.github/workflows/codeql.yml

@@ -28,8 +28,8 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
-    - uses: actions/setup-java@v4
+      uses: actions/checkout@v5
+    - uses: actions/setup-java@v5
       with:
         distribution: temurin
         java-version: 21
@@ -50,7 +50,7 @@ jobs:
     #  uses: github/codeql-action/autobuild@v2
 
     - name: Build
-      run: ./gradlew --build-cache --configuration-cache --configuration-cache-problems=warn --no-daemon app:assembleOseDebug
+      run: ./gradlew --build-cache --configuration-cache --no-daemon app:assembleOseDebug
 
     - name: Perform CodeQL Analysis
       uses: github/codeql-action/analyze@v3

.github/workflows/release.yml

@@ -19,8 +19,8 @@ jobs:
       discussions: write
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
+      - uses: actions/checkout@v5
+      - uses: actions/setup-java@v5
         with:
           distribution: temurin
           java-version: 21
@@ -30,8 +30,8 @@ jobs:
         run: echo ${{ secrets.android_keystore_base64 }} | base64 -d >$GITHUB_WORKSPACE/keystore.jks
 
       - name: Build signed package
-        # Make sure that caches are disabled to generate reproducible release builds
-        run: ./gradlew --no-build-cache --no-configuration-cache --no-daemon app:assembleRelease
+        # Use build cache to speed up building of build variants, but clean caches from previous tests before
+        run: ./gradlew --build-cache --configuration-cache --no-daemon app:clean app:assembleRelease
         env:
           ANDROID_KEYSTORE: ${{ github.workspace }}/keystore.jks
           ANDROID_KEYSTORE_PASSWORD: ${{ secrets.android_keystore_password }}
@@ -45,4 +45,3 @@ jobs:
           files: app/build/outputs/apk/ose/release/*.apk
           fail_on_unmatched_files: true
           generate_release_notes: true
-          discussion_category_name: Announcements

.github/workflows/test-dev.yml

@@ -15,8 +15,8 @@ jobs:
     if: ${{ github.ref == 'refs/heads/main-ose' }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
+      - uses: actions/checkout@v5
+      - uses: actions/setup-java@v5
         with:
           distribution: temurin
           java-version: 21
@@ -27,7 +27,7 @@ jobs:
           cache-encryption-key: ${{ secrets.gradle_encryption_key }}
           dependency-graph: generate-and-submit         # submit Github Dependency Graph info
 
-      - run: ./gradlew --build-cache --configuration-cache --configuration-cache-problems=warn app:compileOseDebugSource
+      - run: ./gradlew --build-cache --configuration-cache app:compileOseDebugSource
 
   test:
     needs: compile
@@ -35,8 +35,8 @@ jobs:
     name: Lint and unit tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
+      - uses: actions/checkout@v5
+      - uses: actions/setup-java@v5
         with:
           distribution: temurin
           java-version: 21
@@ -46,9 +46,9 @@ jobs:
           cache-read-only: true
 
       - name: Run lint
-        run: ./gradlew --build-cache --configuration-cache --configuration-cache-problems=warn app:lintOseDebug
+        run: ./gradlew --build-cache --configuration-cache app:lintOseDebug
       - name: Run unit tests
-        run: ./gradlew --build-cache --configuration-cache --configuration-cache-problems=warn app:testOseDebugUnitTest
+        run: ./gradlew --build-cache --configuration-cache app:testOseDebugUnitTest
 
   test_on_emulator:
     needs: compile
@@ -56,8 +56,8 @@ jobs:
     name: Instrumented tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-java@v4
+      - uses: actions/checkout@v5
+      - uses: actions/setup-java@v5
         with:
           distribution: temurin
           java-version: 21
@@ -79,4 +79,4 @@ jobs:
           key: avd-${{ hashFiles('app/build.gradle.kts') }}   # gradle-managed devices are defined there
 
       - name: Run device tests
-        run: ./gradlew --build-cache --configuration-cache --configuration-cache-problems=warn app:virtualCheck
+        run: ./gradlew --build-cache --configuration-cache app:virtualCheck

README.md

@@ -26,8 +26,7 @@ Parts of DAVx⁵ have been outsourced into these libraries:
 
 * [cert4android](https://github.com/bitfireAT/cert4android) – custom certificate management
 * [dav4jvm](https://github.com/bitfireAT/dav4jvm) – WebDAV/CalDav/CardDAV framework
-* [ical4android](https://github.com/bitfireAT/ical4android) – iCalendar processing and Calendar Provider access
-* [vcard4android](https://github.com/bitfireAT/vcard4android) – vCard processing and Contacts Provider access
+* [synctools](https://github.com/bitfireAT/synctools) – iCalendar/vCard/Tasks processing and content provider access
 
 **If you want to support DAVx⁵, please consider [donating to DAVx⁵](https://www.davx5.com/donate)
 or [purchasing it](https://www.davx5.com/download).**

app/build.gradle.kts

@@ -19,14 +19,16 @@ android {
     defaultConfig {
         applicationId = "at.bitfire.davdroid"
 
-        versionCode = 405000000
-        versionName = "4.5"
+        versionCode = 405040002
+        versionName = "4.5.4-rc.1"
 
-        setProperty("archivesBaseName", "davx5-ose-$versionName")
+        base.archivesName = "davx5-ose-$versionName"
 
         minSdk = 24        // Android 7.0
         targetSdk = 36     // Android 16
 
+        buildConfigField("boolean", "customCertsUI", "true")
+
         testInstrumentationRunner = "at.bitfire.davdroid.HiltTestRunner"
     }
 
@@ -176,14 +178,16 @@ dependencies {
         exclude(group="junit")
         exclude(group="org.ogce", module="xpp3")    // Android has its own XmlPullParser implementation
     }
-    implementation(libs.bitfire.synctools)
+    implementation(libs.bitfire.synctools) {
+        exclude(group="androidx.test")              // synctools declares test rules, but we don't want them in non-test code
+        exclude(group = "junit")
+    }
 
     // third-party libs
     @Suppress("RedundantSuppression")
     implementation(libs.dnsjava)
     implementation(libs.guava)
     implementation(libs.mikepenz.aboutLibraries)
-    implementation(libs.nsk90.kstatemachine)
     implementation(libs.okhttp.base)
     implementation(libs.okhttp.brotli)
     implementation(libs.okhttp.logging)

app/src/androidTest/kotlin/at/bitfire/davdroid/CatchExceptionsRule.kt

@@ -1,37 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid
-
-import org.junit.rules.TestRule
-import org.junit.runner.Description
-import org.junit.runners.model.Statement
-import kotlin.reflect.KClass
-
-/**
- * Use this custom rule to ignore exceptions thrown by another rule.
- *
- * @param innerRule The rule to wrap.
- * @param exceptionsToIgnore The exceptions to ignore.
- */
-class CatchExceptionsRule(
-    private val innerRule: TestRule,
-    private vararg val exceptionsToIgnore: KClass<out Throwable>
-) : TestRule {
-    override fun apply(base: Statement, description: Description): Statement {
-        return object : Statement() {
-            override fun evaluate() {
-                try {
-                    innerRule.apply(base, description).evaluate()
-                } catch (e: Throwable) {
-                    val shouldIgnore = exceptionsToIgnore.any { it.isInstance(e) }
-                    if (shouldIgnore)
-                        base.evaluate()
-                    else
-                        throw e
-                }
-            }
-        }
-    }
-}

app/src/androidTest/kotlin/at/bitfire/davdroid/Dav4jvm.kt

@@ -1,20 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid
-
-import android.util.Xml
-import at.bitfire.dav4jvm.XmlUtils
-import org.junit.Assert.assertTrue
-import org.junit.Test
-
-class Dav4jvm {
-
-    @Test
-    fun test_Dav4jvm_XmlUtils_NewPullParser_RelaxedParsing() {
-        val parser = XmlUtils.newPullParser()
-        assertTrue(parser.getFeature(Xml.FEATURE_RELAXED))
-    }
-
-}

app/src/androidTest/kotlin/at/bitfire/davdroid/ExternalLibrariesTest.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid
+
+import android.util.Xml
+import at.bitfire.dav4jvm.XmlUtils
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class ExternalLibrariesTest {
+
+    @Test
+    fun test_Dav4jvm_XmlUtils_NewPullParser_RelaxedParsing() {
+        val parser = XmlUtils.newPullParser()
+        assertTrue(parser.getFeature(Xml.FEATURE_RELAXED))
+    }
+
+    @Test
+    fun testOkhttpHttpUrl_PublicSuffixList() {
+        // HttpUrl.topPrivateDomain() requires okhttp's internal PublicSuffixList.
+        // In Android, loading the PublicSuffixList is done over AndroidX startup.
+        // This test verifies that everything is working.
+        assertEquals("example.com", "http://example.com".toHttpUrl().topPrivateDomain())
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/HiltTestRunner.kt

@@ -10,8 +10,11 @@ import android.os.Build
 import android.os.Bundle
 import androidx.test.runner.AndroidJUnitRunner
 import at.bitfire.davdroid.di.TestCoroutineDispatchersModule
-import at.bitfire.davdroid.sync.SyncAdapterService
+import at.bitfire.davdroid.test.BuildConfig
+import at.bitfire.synctools.log.LogcatHandler
 import dagger.hilt.android.testing.HiltTestApplication
+import java.util.logging.Level
+import java.util.logging.Logger
 
 @Suppress("unused")
 class HiltTestRunner : AndroidJUnitRunner() {
@@ -22,13 +25,16 @@ class HiltTestRunner : AndroidJUnitRunner() {
     override fun onCreate(arguments: Bundle?) {
         super.onCreate(arguments)
 
+        // set root logger to adb Logcat
+        val rootLogger = Logger.getLogger("")
+        rootLogger.level = Level.ALL
+        rootLogger.handlers.forEach { rootLogger.removeHandler(it) }
+        rootLogger.addHandler(LogcatHandler(BuildConfig.APPLICATION_ID))
+
         // MockK requirements
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P)
             throw AssertionError("MockK requires Android P [https://mockk.io/ANDROID.html]")
 
-        // disable sync adapters
-        SyncAdapterService.syncActive.set(false)
-
         // set main dispatcher for tests (especially runTest)
         TestCoroutineDispatchersModule.initMainDispatcher()
     }

app/src/androidTest/kotlin/at/bitfire/davdroid/InitCalendarProviderRule.kt

@@ -1,123 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid
-
-import android.Manifest
-import android.accounts.Account
-import android.content.ContentProviderClient
-import android.content.ContentUris
-import android.content.ContentValues
-import android.os.Build
-import android.provider.CalendarContract
-import androidx.test.platform.app.InstrumentationRegistry
-import androidx.test.rule.GrantPermissionRule
-import at.bitfire.davdroid.resource.LocalCalendar
-import at.bitfire.davdroid.resource.LocalEvent
-import at.bitfire.ical4android.AndroidCalendar
-import at.bitfire.ical4android.Event
-import net.fortuna.ical4j.model.property.DtStart
-import net.fortuna.ical4j.model.property.RRule
-import org.junit.Assert.assertNotNull
-import org.junit.rules.ExternalResource
-import org.junit.rules.RuleChain
-import java.util.logging.Logger
-
-/**
- * JUnit ClassRule which initializes the AOSP CalendarProvider.
- *
- * It seems that the calendar provider unfortunately forgets the very first requests when it is used the very first time,
- * maybe by some wrongly synchronized database initialization. So things like querying the instances
- * fails in this case.
- *
- * So this rule is needed to allow tests which need the calendar provider to succeed even when the calendar provider
- * is used the very first time (especially in CI tests / a fresh emulator).
- *
- * See [at.bitfire.davdroid.resource.LocalCalendarTest] for an example of how to use this rule.
- */
-class InitCalendarProviderRule private constructor(): ExternalResource() {
-
-    companion object {
-
-        private var isInitialized = false
-        private val logger = Logger.getLogger(InitCalendarProviderRule::javaClass.name)
-
-        fun getInstance(): RuleChain = RuleChain
-            .outerRule(GrantPermissionRule.grant(Manifest.permission.READ_CALENDAR, Manifest.permission.WRITE_CALENDAR))
-            .around(InitCalendarProviderRule())
-
-    }
-
-    override fun before() {
-        if (!isInitialized) {
-            logger.info("Initializing calendar provider")
-            if (Build.VERSION.SDK_INT < 31)
-                logger.warning("Calendar provider initialization may or may not work. See InitCalendarProviderRule")
-
-            val context = InstrumentationRegistry.getInstrumentation().targetContext
-            val client = context.contentResolver.acquireContentProviderClient(CalendarContract.AUTHORITY)
-            assertNotNull("Couldn't acquire calendar provider", client)
-
-            client!!.use {
-                initCalendarProvider(client)
-                isInitialized = true
-            }
-        }
-    }
-
-    private fun initCalendarProvider(provider: ContentProviderClient) {
-        val account = Account("LocalCalendarTest", CalendarContract.ACCOUNT_TYPE_LOCAL)
-
-        // Sometimes, the calendar provider returns an ID for the created calendar, but then fails to find it.
-        var calendarOrNull: LocalCalendar? = null
-        for (i in 0..50) {
-            calendarOrNull = createAndVerifyCalendar(account, provider)
-            if (calendarOrNull != null)
-                break
-            else
-                Thread.sleep(100)
-        }
-        val calendar = calendarOrNull ?: throw IllegalStateException("Couldn't create calendar")
-
-        try {
-            // single event init
-            val normalEvent = Event().apply {
-                dtStart = DtStart("20220120T010203Z")
-                summary = "Event with 1 instance"
-            }
-            val normalLocalEvent = LocalEvent(calendar, normalEvent, null, null, null, 0)
-            normalLocalEvent.add()
-            LocalEvent.numInstances(provider, account, normalLocalEvent.id!!)
-
-            // recurring event init
-            val recurringEvent = Event().apply {
-                dtStart = DtStart("20220120T010203Z")
-                summary = "Event over 22 years"
-                rRules.add(RRule("FREQ=YEARLY;UNTIL=20740119T010203Z"))     // year needs to be  >2074 (not supported by Android <11 Calendar Storage)
-            }
-            val localRecurringEvent = LocalEvent(calendar, recurringEvent, null, null, null, 0)
-            localRecurringEvent.add()
-            LocalEvent.numInstances(provider, account, localRecurringEvent.id!!)
-        } finally {
-            calendar.delete()
-        }
-    }
-
-    private fun createAndVerifyCalendar(account: Account, provider: ContentProviderClient): LocalCalendar? {
-        val uri = AndroidCalendar.create(account, provider, ContentValues())
-
-        return try {
-            AndroidCalendar.findByID(
-                account,
-                provider,
-                LocalCalendar.Factory,
-                ContentUris.parseId(uri)
-            )
-        } catch (e: Exception) {
-            logger.warning("Couldn't find calendar after creation: $e")
-            null
-        }
-    }
-
-}

app/src/androidTest/kotlin/at/bitfire/davdroid/db/HomeSetDaoTest.kt

@@ -0,0 +1,97 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.db
+
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import javax.inject.Inject
+
+@HiltAndroidTest
+class HomeSetDaoTest {
+
+    @get:Rule
+    var hiltRule = HiltAndroidRule(this)
+
+    @Inject
+    lateinit var db: AppDatabase
+    lateinit var dao: HomeSetDao
+    var serviceId: Long = 0
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+        dao = db.homeSetDao()
+
+        serviceId = db.serviceDao().insertOrReplace(
+            Service(id=0, accountName="test", type= Service.TYPE_CALDAV, principal = null)
+        )
+    }
+
+    @After
+    fun tearDown() {
+        db.serviceDao().deleteAll()
+    }
+
+
+    @Test
+    fun testInsertOrUpdate() {
+        // should insert new row or update (upsert) existing row - without changing its key!
+        val entry1 = HomeSet(id=0, serviceId=serviceId, personal=true, url="https://example.com/1".toHttpUrl())
+        val insertId1 = dao.insertOrUpdateByUrlBlocking(entry1)
+        assertEquals(1L, insertId1)
+        assertEquals(entry1.copy(id = 1L), dao.getById(1))
+
+        val updatedEntry1 = HomeSet(id=0, serviceId=serviceId, personal=true, url="https://example.com/1".toHttpUrl(), displayName="Updated Entry")
+        val updateId1 = dao.insertOrUpdateByUrlBlocking(updatedEntry1)
+        assertEquals(1L, updateId1)
+        assertEquals(updatedEntry1.copy(id = 1L), dao.getById(1))
+
+        val entry2 = HomeSet(id=0, serviceId=serviceId, personal=true, url= "https://example.com/2".toHttpUrl())
+        val insertId2 = dao.insertOrUpdateByUrlBlocking(entry2)
+        assertEquals(2L, insertId2)
+        assertEquals(entry2.copy(id = 2L), dao.getById(2))
+    }
+
+    @Test
+    fun testInsertOrUpdate_TransactionSafe() {
+        runBlocking(Dispatchers.IO) {
+            for (i in 0..9999)
+                launch {
+                    dao.insertOrUpdateByUrlBlocking(
+                        HomeSet(
+                            id = 0,
+                            serviceId = serviceId,
+                            url = "https://example.com/".toHttpUrl(),
+                            personal = true
+                        )
+                    )
+                }
+        }
+        assertEquals(1, dao.getByService(serviceId).size)
+    }
+
+    @Test
+    fun testDelete() {
+        // should delete row with given primary key (id)
+        val entry1 = HomeSet(id=1, serviceId=serviceId, personal=true, url= "https://example.com/1".toHttpUrl())
+
+        val insertId1 = dao.insertOrUpdateByUrlBlocking(entry1)
+        assertEquals(1L, insertId1)
+        assertEquals(entry1, dao.getById(1L))
+
+        dao.delete(entry1)
+        assertEquals(null, dao.getById(1L))
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/db/SyncStatsDaoTest.kt

@@ -0,0 +1,77 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.db
+
+import androidx.sqlite.SQLiteException
+import at.bitfire.davdroid.sync.SyncDataType
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import kotlinx.coroutines.test.runTest
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import org.junit.After
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import javax.inject.Inject
+
+@HiltAndroidTest
+class SyncStatsDaoTest {
+
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @Inject
+    lateinit var db: AppDatabase
+    var collectionId: Long = 0
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+
+        val serviceId = db.serviceDao().insertOrReplace(Service(
+            id = 0,
+            accountName = "test@example.com",
+            type = Service.TYPE_CALDAV
+        ))
+        collectionId = db.collectionDao().insert(Collection(
+            id = 0,
+            serviceId = serviceId,
+            type = Collection.TYPE_CALENDAR,
+            url = "https://example.com".toHttpUrl()
+        ))
+    }
+
+    @After
+    fun tearDown() {
+        db.serviceDao().deleteAll()
+    }
+
+    @Test
+    fun testInsertOrReplace_ExistingForeignKey() = runTest {
+        val dao = db.syncStatsDao()
+        dao.insertOrReplace(
+            SyncStats(
+                id = 0,
+                collectionId = collectionId,
+                dataType = SyncDataType.CONTACTS.toString(),
+                lastSync = System.currentTimeMillis()
+            )
+        )
+    }
+
+    @Test(expected = SQLiteException::class)
+    fun testInsertOrReplace_MissingForeignKey() = runTest {
+        val dao = db.syncStatsDao()
+        dao.insertOrReplace(
+            SyncStats(
+                id = 0,
+                collectionId = 12345,
+                dataType = SyncDataType.CONTACTS.toString(),
+                lastSync = System.currentTimeMillis()
+            )
+        )
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/db/migration/DatabaseMigrationTest.kt

@@ -44,6 +44,11 @@ abstract class DatabaseMigrationTest(
     /**
      * Used for testing the migration process from [toVersion]-1 to [toVersion].
      *
+     * Note: SQLite's foreign key constraint enforcement is not enabled in tests. We need
+     * to enable it ourselves using setting "PRAGMA foreign_keys=ON" directly after opening
+     * a new database connection (works per connection). In tests it's usually more practical
+     * not to do so, however. In production database connections room enables it for us.
+     *
      * @param prepare      Callback to prepare the database. Will be run with database schema in version [toVersion] - 1.
      * @param validate     Callback to validate the migration result. Will be run with database schema in version [toVersion].
      */
@@ -61,6 +66,8 @@ abstract class DatabaseMigrationTest(
         // Prepare the database with the initial version.
         val dbName = "test"
         helper.createDatabase(dbName, version = toVersion - 1).apply {
+            // We could enable foreign key constraint enforcement here
+            // by setting "PRAGMA foreign_keys=ON".
             prepare(this)
             close()
         }

app/src/androidTest/kotlin/at/bitfire/davdroid/di/FakeSyncAdapterModule.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.di
+
+import at.bitfire.davdroid.sync.FakeSyncAdapter
+import at.bitfire.davdroid.sync.adapter.SyncAdapter
+import at.bitfire.davdroid.sync.adapter.SyncAdapterImpl
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.components.SingletonComponent
+import dagger.hilt.testing.TestInstallIn
+
+@Module
+@TestInstallIn(components = [SingletonComponent::class], replaces = [SyncAdapterImpl.RealSyncAdapterModule::class])
+abstract class FakeSyncAdapterModule {
+    @Binds
+    abstract fun provide(impl: FakeSyncAdapter): SyncAdapter
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/di/TestLoggerModule.kt

@@ -1,33 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.di
-
-import at.bitfire.davdroid.log.LogcatHandler
-import dagger.Module
-import dagger.Provides
-import dagger.hilt.components.SingletonComponent
-import dagger.hilt.testing.TestInstallIn
-import java.util.logging.Level
-import java.util.logging.Logger
-import javax.inject.Singleton
-
-/**
- * Module that provides verbose logging for tests.
- */
-@TestInstallIn(
-    components = [SingletonComponent::class],
-    replaces = [LoggerModule::class]
-)
-@Module
-class TestLoggerModule {
-
-    @Provides
-    @Singleton
-    fun logger(): Logger = Logger.getGlobal().apply {
-        level = Level.ALL
-        addHandler(LogcatHandler())
-    }
-
-}

app/src/androidTest/kotlin/at/bitfire/davdroid/network/Android10ResolverTest.kt

@@ -19,7 +19,7 @@ class Android10ResolverTest {
     val FQDN_DAVX5 = "www.davx5.com"
 
     @Test
-    @SdkSuppress(minSdkVersion = Build.VERSION_CODES.Q)
+    @SdkSuppress(minSdkVersion = Build.VERSION_CODES.Q, maxSdkVersion = 34)
     fun testResolveA() {
         val www = InetAddress.getAllByName(FQDN_DAVX5).filterIsInstance<Inet4Address>().first()
 

app/src/androidTest/kotlin/at/bitfire/davdroid/network/OkhttpClientTest.kt

@@ -2,9 +2,9 @@
  * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
  */
 
-package at.bitfire.davdroid
+package at.bitfire.davdroid.network
 
-import at.bitfire.davdroid.network.HttpClient
+import androidx.test.filters.SdkSuppress
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import okhttp3.Request
@@ -29,13 +29,16 @@ class OkhttpClientTest {
 
 
     @Test
+    @SdkSuppress(maxSdkVersion = 34)
     fun testIcloudWithSettings() {
         httpClientBuilder.build().use { client ->
             client.okHttpClient
-                .newCall(Request.Builder()
-                .get()
-                .url("https://icloud.com")
-                .build())
+                .newCall(
+                    Request.Builder()
+                        .get()
+                        .url("https://icloud.com")
+                        .build()
+                )
                 .execute()
         }
     }

app/src/androidTest/kotlin/at/bitfire/davdroid/repository/DavHomeSetRepositoryTest.kt

@@ -1,74 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.repository
-
-import at.bitfire.davdroid.db.HomeSet
-import at.bitfire.davdroid.db.Service
-import dagger.hilt.android.testing.HiltAndroidRule
-import dagger.hilt.android.testing.HiltAndroidTest
-import okhttp3.HttpUrl.Companion.toHttpUrl
-import org.junit.Assert.assertEquals
-import org.junit.Before
-import org.junit.Rule
-import org.junit.Test
-import javax.inject.Inject
-
-@HiltAndroidTest
-class DavHomeSetRepositoryTest {
-
-    @Inject
-    lateinit var repository: DavHomeSetRepository
-
-    @Inject
-    lateinit var serviceRepository: DavServiceRepository
-
-    @get:Rule
-    var hiltRule = HiltAndroidRule(this)
-
-    var serviceId: Long = 0
-
-    @Before
-    fun setUp() {
-        hiltRule.inject()
-
-        serviceId = serviceRepository.insertOrReplaceBlocking(
-            Service(id=0, accountName="test", type= Service.TYPE_CALDAV, principal = null)
-        )
-    }
-
-
-    @Test
-    fun testInsertOrUpdate() {
-        // should insert new row or update (upsert) existing row - without changing its key!
-        val entry1 = HomeSet(id=0, serviceId=serviceId, personal=true, url="https://example.com/1".toHttpUrl())
-        val insertId1 = repository.insertOrUpdateByUrlBlocking(entry1)
-        assertEquals(1L, insertId1)
-        assertEquals(entry1.copy(id = 1L), repository.getByIdBlocking(1L))
-
-        val updatedEntry1 = HomeSet(id=0, serviceId=serviceId, personal=true, url="https://example.com/1".toHttpUrl(), displayName="Updated Entry")
-        val updateId1 = repository.insertOrUpdateByUrlBlocking(updatedEntry1)
-        assertEquals(1L, updateId1)
-        assertEquals(updatedEntry1.copy(id = 1L), repository.getByIdBlocking(1L))
-
-        val entry2 = HomeSet(id=0, serviceId=serviceId, personal=true, url= "https://example.com/2".toHttpUrl())
-        val insertId2 = repository.insertOrUpdateByUrlBlocking(entry2)
-        assertEquals(2L, insertId2)
-        assertEquals(entry2.copy(id = 2L), repository.getByIdBlocking(2L))
-    }
-
-    @Test
-    fun testDeleteBlocking() {
-        // should delete row with given primary key (id)
-        val entry1 = HomeSet(id=1, serviceId=serviceId, personal=true, url= "https://example.com/1".toHttpUrl())
-
-        val insertId1 = repository.insertOrUpdateByUrlBlocking(entry1)
-        assertEquals(1L, insertId1)
-        assertEquals(entry1, repository.getByIdBlocking(1L))
-
-        repository.deleteBlocking(entry1)
-        assertEquals(null, repository.getByIdBlocking(1L))
-    }
-
-}

app/src/androidTest/kotlin/at/bitfire/davdroid/resource/LocalAddressBookTest.kt

@@ -29,6 +29,7 @@ import org.junit.Rule
 import org.junit.Test
 import java.io.FileNotFoundException
 import java.util.LinkedList
+import java.util.Optional
 import javax.inject.Inject
 
 @HiltAndroidTest
@@ -98,7 +99,7 @@ class LocalAddressBookTest {
             val id = ContentUris.parseId(uri)
 
             // make sure it's not dirty
-            localGroup.clearDirty(null, null, null)
+            localGroup.clearDirty(Optional.empty(), null, null)
             assertFalse("Group is dirty before moving", isGroupDirty(addressBook, id))
 
             // rename address book
@@ -127,7 +128,7 @@ class LocalAddressBookTest {
      */
     fun isContactDirty(adddressBook: LocalAddressBook, id: Long): Boolean {
         val uri = ContentUris.withAppendedId(adddressBook.rawContactsSyncUri(), id)
-        provider!!.query(uri, arrayOf(ContactsContract.RawContacts.DIRTY), null, null, null)?.use { cursor ->
+        provider.query(uri, arrayOf(ContactsContract.RawContacts.DIRTY), null, null, null)?.use { cursor ->
             if (cursor.moveToFirst())
                 return cursor.getInt(0) != 0
         }
@@ -143,7 +144,7 @@ class LocalAddressBookTest {
      */
     fun isGroupDirty(adddressBook: LocalAddressBook, id: Long): Boolean {
         val uri = ContentUris.withAppendedId(adddressBook.groupsSyncUri(), id)
-        provider!!.query(uri, arrayOf(ContactsContract.Groups.DIRTY), null, null, null)?.use { cursor ->
+        provider.query(uri, arrayOf(ContactsContract.Groups.DIRTY), null, null, null)?.use { cursor ->
             if (cursor.moveToFirst())
                 return cursor.getInt(0) != 0
         }

app/src/androidTest/kotlin/at/bitfire/davdroid/resource/LocalCalendarTest.kt

@@ -8,65 +8,68 @@ import android.accounts.Account
 import android.content.ContentProviderClient
 import android.content.ContentUris
 import android.content.ContentValues
+import android.content.Entity
 import android.provider.CalendarContract
 import android.provider.CalendarContract.ACCOUNT_TYPE_LOCAL
 import android.provider.CalendarContract.Events
+import androidx.core.content.contentValuesOf
 import androidx.test.platform.app.InstrumentationRegistry
-import at.bitfire.davdroid.InitCalendarProviderRule
-import at.bitfire.ical4android.AndroidCalendar
 import at.bitfire.ical4android.Event
 import at.bitfire.ical4android.util.MiscUtils.asSyncAdapter
 import at.bitfire.ical4android.util.MiscUtils.closeCompat
+import at.bitfire.synctools.storage.calendar.AndroidCalendar
+import at.bitfire.synctools.storage.calendar.AndroidCalendarProvider
+import at.bitfire.synctools.storage.calendar.AndroidEvent2
+import at.bitfire.synctools.test.InitCalendarProviderRule
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
 import net.fortuna.ical4j.model.property.DtStart
 import net.fortuna.ical4j.model.property.RRule
 import net.fortuna.ical4j.model.property.RecurrenceId
 import net.fortuna.ical4j.model.property.Status
 import org.junit.After
-import org.junit.AfterClass
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
 import org.junit.Before
-import org.junit.BeforeClass
-import org.junit.ClassRule
+import org.junit.Rule
 import org.junit.Test
 import org.junit.rules.TestRule
+import javax.inject.Inject
 
+@HiltAndroidTest
 class LocalCalendarTest {
 
-    companion object {
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
 
-        @JvmField
-        @ClassRule
-        val initCalendarProviderRule: TestRule = InitCalendarProviderRule.getInstance()
+    @get:Rule
+    val initCalendarProviderRule: TestRule = InitCalendarProviderRule.initialize()
 
-        private lateinit var provider: ContentProviderClient
-
-        @BeforeClass
-        @JvmStatic
-        fun setUpClass() {
-            val context = InstrumentationRegistry.getInstrumentation().targetContext
-            provider = context.contentResolver.acquireContentProviderClient(CalendarContract.AUTHORITY)!!
-        }
-
-        @AfterClass
-        @JvmStatic
-        fun tearDownClass() {
-            provider.closeCompat()
-        }
-
-    }
+    @Inject
+    lateinit var localCalendarFactory: LocalCalendar.Factory
 
     private val account = Account("LocalCalendarTest", ACCOUNT_TYPE_LOCAL)
+    private lateinit var androidCalendar: AndroidCalendar
+    private lateinit var client: ContentProviderClient
     private lateinit var calendar: LocalCalendar
 
     @Before
     fun setUp() {
-        val uri = AndroidCalendar.create(account, provider, ContentValues())
-        calendar = AndroidCalendar.findByID(account, provider, LocalCalendar.Factory, ContentUris.parseId(uri))
+        hiltRule.inject()
+
+        val context = InstrumentationRegistry.getInstrumentation().targetContext
+        client = context.contentResolver.acquireContentProviderClient(CalendarContract.AUTHORITY)!!
+
+        val provider = AndroidCalendarProvider(account, client)
+        androidCalendar = provider.createAndGetCalendar(ContentValues())
+        calendar = localCalendarFactory.create(androidCalendar)
     }
 
     @After
     fun tearDown() {
-        calendar.delete()
+        androidCalendar.delete()
+        client.closeCompat()
     }
 
 
@@ -96,12 +99,18 @@ class LocalCalendarTest {
                 status = Status.VEVENT_CANCELLED
             })
         }
-        val localEvent = LocalEvent(calendar, event, "filename.ics", null, null, LocalResource.FLAG_REMOTELY_PRESENT)
-        localEvent.add()
-        val eventId = localEvent.id!!
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
+        val eventId = localEvent.id
 
         // set event as dirty
-        provider.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
+        client.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
             put(Events.DIRTY, 1)
         }, null, null)
 
@@ -109,7 +118,7 @@ class LocalCalendarTest {
         calendar.deleteDirtyEventsWithoutInstances()
 
         // verify that event is now marked as deleted
-        provider.query(
+        client.query(
             ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId),
             arrayOf(Events.DELETED), null, null, null
         )!!.use { cursor ->
@@ -126,26 +135,102 @@ class LocalCalendarTest {
             summary = "Event with 3 instances"
             rRules.add(RRule("FREQ=DAILY;COUNT=3"))
         }
-        val localEvent = LocalEvent(calendar, event, "filename.ics", null, null, LocalResource.FLAG_REMOTELY_PRESENT)
-        localEvent.add()
-        val eventId = localEvent.id!!
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
+        val eventUrl = androidCalendar.eventUri(localEvent.id)
 
         // set event as dirty
-        provider.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
-            put(Events.DIRTY, 1)
-        }, null, null)
+        client.update(eventUrl, contentValuesOf(
+            Events.DIRTY to 1
+        ), null, null)
 
         // this method should mark the event as deleted
         calendar.deleteDirtyEventsWithoutInstances()
 
         // verify that event is not marked as deleted
-        provider.query(
-            ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId),
-            arrayOf(Events.DELETED), null, null, null
-        )!!.use { cursor ->
+        client.query(eventUrl, arrayOf(Events.DELETED), null, null, null)!!.use { cursor ->
             cursor.moveToNext()
             assertEquals(0, cursor.getInt(0))
         }
     }
 
+    /**
+     * Verifies that [LocalCalendar.removeNotDirtyMarked] works as expected.
+     * @param contentValues values to set on the event. Required:
+     * - [Events._ID]
+     * - [Events.DIRTY]
+     */
+    private fun testRemoveNotDirtyMarked(contentValues: ContentValues) {
+        val id = androidCalendar.addEvent(Entity(
+            contentValuesOf(
+                Events.CALENDAR_ID to androidCalendar.id,
+                Events.DTSTART to System.currentTimeMillis(),
+                Events.DTEND to System.currentTimeMillis(),
+                Events.TITLE to "Some Event",
+                AndroidEvent2.COLUMN_FLAGS to 123
+            ).apply { putAll(contentValues) }
+        ))
+
+        calendar.removeNotDirtyMarked(123)
+
+        assertNull(androidCalendar.getEvent(id))
+    }
+
+    @Test
+    fun testRemoveNotDirtyMarked_IdLargerThanIntMaxValue() = testRemoveNotDirtyMarked(
+        contentValuesOf(Events._ID to Int.MAX_VALUE.toLong() + 10, Events.DIRTY to 0)
+    )
+
+    @Test
+    fun testRemoveNotDirtyMarked_DirtyIs0() = testRemoveNotDirtyMarked(
+        contentValuesOf(Events._ID to 1, Events.DIRTY to 0)
+    )
+
+    @Test
+    fun testRemoveNotDirtyMarked_DirtyNull() = testRemoveNotDirtyMarked(
+        contentValuesOf(Events._ID to 1, Events.DIRTY to null)
+    )
+
+    /**
+     * Verifies that [LocalCalendar.markNotDirty] works as expected.
+     * @param contentValues values to set on the event. Required:
+     * - [Events.DIRTY]
+     */
+    private fun testMarkNotDirty(contentValues: ContentValues) {
+        val id = androidCalendar.addEvent(Entity(
+            contentValuesOf(
+                Events.CALENDAR_ID to androidCalendar.id,
+                Events._ID to 1,
+                Events.DTSTART to System.currentTimeMillis(),
+                Events.DTEND to System.currentTimeMillis(),
+                Events.TITLE to "Some Event",
+                AndroidEvent2.COLUMN_FLAGS to 123
+            ).apply { putAll(contentValues) }
+        ))
+
+        val updated = calendar.markNotDirty(321)
+        assertEquals(1, updated)
+        assertEquals(321, androidCalendar.getEvent(id)?.flags)
+    }
+
+    @Test
+    fun test_markNotDirty_DirtyIs0() = testMarkNotDirty(
+        contentValuesOf(
+            Events.DIRTY to 0
+        )
+    )
+
+    @Test
+    fun test_markNotDirty_DirtyIsNull() = testMarkNotDirty(
+        contentValuesOf(
+            Events.DIRTY to null
+        )
+    )
+
 }

app/src/androidTest/kotlin/at/bitfire/davdroid/resource/LocalEventTest.kt

@@ -4,292 +4,65 @@
 
 package at.bitfire.davdroid.resource
 
+import android.Manifest
 import android.accounts.Account
 import android.content.ContentProviderClient
 import android.content.ContentUris
 import android.content.ContentValues
-import android.os.Build
 import android.provider.CalendarContract
 import android.provider.CalendarContract.ACCOUNT_TYPE_LOCAL
 import android.provider.CalendarContract.Events
 import androidx.test.platform.app.InstrumentationRegistry
-import at.bitfire.davdroid.InitCalendarProviderRule
-import at.bitfire.ical4android.AndroidCalendar
+import androidx.test.rule.GrantPermissionRule
 import at.bitfire.ical4android.Event
 import at.bitfire.ical4android.util.MiscUtils.closeCompat
+import at.bitfire.synctools.storage.calendar.AndroidCalendarProvider
 import at.techbee.jtx.JtxContract.asSyncAdapter
-import net.fortuna.ical4j.model.Date
-import net.fortuna.ical4j.model.DateList
-import net.fortuna.ical4j.model.parameter.Value
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
 import net.fortuna.ical4j.model.property.DtStart
-import net.fortuna.ical4j.model.property.ExDate
 import net.fortuna.ical4j.model.property.RRule
 import net.fortuna.ical4j.model.property.RecurrenceId
 import net.fortuna.ical4j.model.property.Status
 import org.junit.After
-import org.junit.AfterClass
 import org.junit.Assert.assertEquals
-import org.junit.Assert.assertNull
-import org.junit.Assert.assertTrue
 import org.junit.Before
-import org.junit.BeforeClass
-import org.junit.ClassRule
+import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.TestRule
 import java.util.UUID
+import javax.inject.Inject
 
+@HiltAndroidTest
 class LocalEventTest {
 
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @get:Rule
+    val permissionRule = GrantPermissionRule.grant(Manifest.permission.READ_CALENDAR, Manifest.permission.WRITE_CALENDAR)
+
+    @Inject
+    lateinit var localCalendarFactory: LocalCalendar.Factory
+
     private val account = Account("LocalCalendarTest", ACCOUNT_TYPE_LOCAL)
+    private lateinit var client: ContentProviderClient
     private lateinit var calendar: LocalCalendar
 
     @Before
     fun setUp() {
-        val uri = AndroidCalendar.create(account, provider, ContentValues())
-        calendar = AndroidCalendar.findByID(account, provider, LocalCalendar.Factory, ContentUris.parseId(uri))
+        hiltRule.inject()
+
+        val context = InstrumentationRegistry.getInstrumentation().targetContext
+        client = context.contentResolver.acquireContentProviderClient(CalendarContract.AUTHORITY)!!
+
+        val provider = AndroidCalendarProvider(account, client)
+        calendar = localCalendarFactory.create(provider.createAndGetCalendar(ContentValues()))
     }
 
     @After
-    fun removeCalendar() {
-        calendar.delete()
-    }
-
-
-    @Test
-    fun testNumDirectInstances_SingleInstance() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 1 instance"
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertEquals(1, LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    fun testNumDirectInstances_Recurring() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 5 instances"
-            rRules.add(RRule("FREQ=DAILY;COUNT=5"))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertEquals(5, LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    fun testNumDirectInstances_Recurring_Endless() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event without end"
-            rRules.add(RRule("FREQ=DAILY"))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertNull(LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    // flaky, needs InitCalendarProviderRule
-    fun testNumDirectInstances_Recurring_LateEnd() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 53 years"
-            rRules.add(RRule("FREQ=YEARLY;UNTIL=20740119T010203Z"))     // year 2074 is not supported by Android <11 Calendar Storage
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R)
-            assertEquals(52, LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-        else
-            assertNull(LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    // flaky, needs InitCalendarProviderRule
-    fun testNumDirectInstances_Recurring_ManyInstances() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 2 years"
-            rRules.add(RRule("FREQ=DAILY;UNTIL=20240120T010203Z"))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-        val number = LocalEvent.numDirectInstances(provider, account, localEvent.id!!)
-
-        // Some android versions (i.e. <=Q and S) return 365*2 instances (wrong, 365*2+1 => correct),
-        // but we are satisfied with either result for now
-        assertTrue(number == 365*2 || number == 365*2+1)
-    }
-
-    @Test
-    // flaky, needs InitCalendarProviderRule
-    fun testNumDirectInstances_RecurringWithExdate() {
-        val event = Event().apply {
-            dtStart = DtStart(Date("20220120T010203Z"))
-            summary = "Event with 5 instances"
-            rRules.add(RRule("FREQ=DAILY;COUNT=5"))
-            exDates.add(ExDate(DateList("20220121T010203Z", Value.DATE_TIME)))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertEquals(4, LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    fun testNumDirectInstances_RecurringWithExceptions() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 5 instances"
-            rRules.add(RRule("FREQ=DAILY;COUNT=5"))
-            exceptions.add(Event().apply {
-                recurrenceId = RecurrenceId("20220122T010203Z")
-                dtStart = DtStart("20220122T130203Z")
-                summary = "Exception on 3rd day"
-            })
-            exceptions.add(Event().apply {
-                recurrenceId = RecurrenceId("20220124T010203Z")
-                dtStart = DtStart("20220122T160203Z")
-                summary = "Exception on 5th day"
-            })
-        }
-        val localEvent = LocalEvent(calendar, event, "filename.ics", null, null, 0)
-        localEvent.add()
-
-        assertEquals(5-2, LocalEvent.numDirectInstances(provider, account, localEvent.id!!))
-    }
-
-
-    @Test
-    // flaky, needs InitCalendarProviderRule
-    fun testNumInstances_SingleInstance() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 1 instance"
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertEquals(1, LocalEvent.numInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    fun testNumInstances_Recurring() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 5 instances"
-            rRules.add(RRule("FREQ=DAILY;COUNT=5"))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertEquals(5, LocalEvent.numInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    fun testNumInstances_Recurring_Endless() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with infinite instances"
-            rRules.add(RRule("FREQ=YEARLY"))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertNull(LocalEvent.numInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    // flaky, needs InitCalendarProviderRule
-    fun testNumInstances_Recurring_LateEnd() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event over 22 years"
-            rRules.add(RRule("FREQ=YEARLY;UNTIL=20740119T010203Z"))     // year 2074 not supported by Android <11 Calendar Storage
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R)
-            assertEquals(52, LocalEvent.numInstances(provider, account, localEvent.id!!))
-        else
-            assertNull(LocalEvent.numInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    // flaky, needs InitCalendarProviderRule
-    fun testNumInstances_Recurring_ManyInstances() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event over two years"
-            rRules.add(RRule("FREQ=DAILY;UNTIL=20240120T010203Z"))
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        assertEquals(
-            if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.Q)
-                365*2       // Android <10: does not include UNTIL (incorrect!)
-            else
-                365*2 + 1,  // Android ≥10: includes UNTIL (correct)
-            LocalEvent.numInstances(provider, account, localEvent.id!!))
-    }
-
-    @Test
-    fun testNumInstances_RecurringWithExceptions() {
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "Event with 6 instances"
-            rRules.add(RRule("FREQ=DAILY;COUNT=6"))
-            exceptions.add(Event().apply {
-                recurrenceId = RecurrenceId("20220122T010203Z")
-                dtStart = DtStart("20220122T130203Z")
-                summary = "Exception on 3rd day"
-            })
-            exceptions.add(Event().apply {
-                recurrenceId = RecurrenceId("20220124T010203Z")
-                dtStart = DtStart("20220122T160203Z")
-                summary = "Exception on 5th day"
-            })
-        }
-        val localEvent = LocalEvent(calendar, event, "filename.ics", null, null, 0)
-        localEvent.add()
-
-        calendar.findById(localEvent.id!!)
-
-        assertEquals(6, LocalEvent.numInstances(provider, account, localEvent.id!!))
-    }
-
-
-    @Test
-    fun testMarkEventAsDeleted() {
-        // Create event
-        val event = Event().apply {
-            dtStart = DtStart("20220120T010203Z")
-            summary = "A fine event"
-        }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()
-
-        // Delete event
-        LocalEvent.markAsDeleted(provider, account, localEvent.id!!)
-
-        // Get the status of whether the event is deleted
-        provider.query(
-            ContentUris.withAppendedId(Events.CONTENT_URI, localEvent.id!!).asSyncAdapter(account),
-            arrayOf(Events.DELETED),
-            null,
-            null, null
-        )!!.use { cursor ->
-            cursor.moveToFirst()
-            assertEquals(1, cursor.getInt(0))
-        }
+    fun tearDown() {
+        calendar.androidCalendar.delete()
+        client.closeCompat()
     }
 
 
@@ -300,8 +73,15 @@ class LocalEventTest {
             dtStart = DtStart("20220120T010203Z")
             summary = "Event without uid"
         }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add()    // save it to calendar storage
+
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
 
         // prepare for upload - this should generate a new random uuid, returned as filename
         val fileNameWithSuffix = localEvent.prepareForUpload()
@@ -311,7 +91,7 @@ class LocalEventTest {
         UUID.fromString(fileName)
 
         // UID in calendar storage should be the same as file name
-        provider.query(
+        client.query(
             ContentUris.withAppendedId(Events.CONTENT_URI, localEvent.id!!).asSyncAdapter(account),
             arrayOf(Events.UID_2445), null, null, null
         )!!.use { cursor ->
@@ -328,8 +108,14 @@ class LocalEventTest {
             summary = "Event with normal uid"
             uid = "some-event@hostname.tld"     // old UID format, UUID would be new format
         }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add() // save it to calendar storage
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
 
         // prepare for upload - this should use the UID for the file name
         val fileNameWithSuffix = localEvent.prepareForUpload()
@@ -338,7 +124,7 @@ class LocalEventTest {
         assertEquals(event.uid, fileName)
 
         // UID in calendar storage should still be set, too
-        provider.query(
+        client.query(
             ContentUris.withAppendedId(Events.CONTENT_URI, localEvent.id!!).asSyncAdapter(account),
             arrayOf(Events.UID_2445), null, null, null
         )!!.use { cursor ->
@@ -355,8 +141,14 @@ class LocalEventTest {
             summary = "Event with funny uid"
             uid = "https://www.example.com/events/asdfewfe-cxyb-ewrws-sadfrwerxyvser-asdfxye-"
         }
-        val localEvent = LocalEvent(calendar, event, null, null, null, 0)
-        localEvent.add() // save it to calendar storage
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
 
         // prepare for upload - this should generate a new random uuid, returned as filename
         val fileNameWithSuffix = localEvent.prepareForUpload()
@@ -366,7 +158,7 @@ class LocalEventTest {
         UUID.fromString(fileName)
 
         // UID in calendar storage shouldn't have been changed
-        provider.query(
+        client.query(
             ContentUris.withAppendedId(Events.CONTENT_URI, localEvent.id!!).asSyncAdapter(account),
             arrayOf(Events.UID_2445), null, null, null
         )!!.use { cursor ->
@@ -407,12 +199,18 @@ class LocalEventTest {
                 status = Status.VEVENT_CANCELLED
             })
         }
-        val localEvent = LocalEvent(calendar, event, "filename.ics", null, null, LocalResource.FLAG_REMOTELY_PRESENT)
-        localEvent.add()
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
         val eventId = localEvent.id!!
 
         // set event as dirty
-        provider.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
+        client.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
             put(Events.DIRTY, 1)
         }, null, null)
 
@@ -420,7 +218,7 @@ class LocalEventTest {
         calendar.deleteDirtyEventsWithoutInstances()
 
         // verify that event is now marked as deleted
-        provider.query(
+        client.query(
             ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId),
             arrayOf(Events.DELETED), null, null, null
         )!!.use { cursor ->
@@ -436,12 +234,18 @@ class LocalEventTest {
             summary = "Event with 3 instances"
             rRules.add(RRule("FREQ=DAILY;COUNT=3"))
         }
-        val localEvent = LocalEvent(calendar, event, "filename.ics", null, null, LocalResource.FLAG_REMOTELY_PRESENT)
-        localEvent.add()
+        calendar.add(
+            event = event,
+            fileName = "filename.ics",
+            eTag = null,
+            scheduleTag = null,
+            flags = LocalResource.FLAG_REMOTELY_PRESENT
+        )
+        val localEvent = calendar.findByName("filename.ics")!!
         val eventId = localEvent.id!!
 
         // set event as dirty
-        provider.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
+        client.update(ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId), ContentValues(1).apply {
             put(Events.DIRTY, 1)
         }, null, null)
 
@@ -449,7 +253,7 @@ class LocalEventTest {
         calendar.deleteDirtyEventsWithoutInstances()
 
         // verify that event is not marked as deleted
-        provider.query(
+        client.query(
             ContentUris.withAppendedId(Events.CONTENT_URI.asSyncAdapter(account), eventId),
             arrayOf(Events.DELETED), null, null, null
         )!!.use { cursor ->
@@ -458,28 +262,4 @@ class LocalEventTest {
         }
     }
 
-
-    companion object {
-
-        @JvmField
-        @ClassRule
-        val initCalendarProviderRule: TestRule = InitCalendarProviderRule.getInstance()
-
-        private lateinit var provider: ContentProviderClient
-
-        @BeforeClass
-        @JvmStatic
-        fun setUpClass() {
-            val context = InstrumentationRegistry.getInstrumentation().targetContext
-            provider = context.contentResolver.acquireContentProviderClient(CalendarContract.AUTHORITY)!!
-        }
-
-        @AfterClass
-        @JvmStatic
-        fun tearDownClass() {
-            provider.closeCompat()
-        }
-
-    }
-
 }

app/src/androidTest/kotlin/at/bitfire/davdroid/resource/LocalGroupTest.kt

@@ -14,7 +14,7 @@ import android.provider.ContactsContract
 import android.provider.ContactsContract.CommonDataKinds.GroupMembership
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.rule.GrantPermissionRule
-import at.bitfire.vcard4android.BatchOperation
+import at.bitfire.synctools.storage.ContactsBatchOperation
 import at.bitfire.vcard4android.CachedGroupMembership
 import at.bitfire.vcard4android.Contact
 import at.bitfire.vcard4android.GroupMethod
@@ -32,6 +32,7 @@ import org.junit.BeforeClass
 import org.junit.ClassRule
 import org.junit.Rule
 import org.junit.Test
+import java.util.Optional
 import javax.inject.Inject
 
 @HiltAndroidTest
@@ -115,7 +116,7 @@ class LocalGroupTest {
             val group = newGroup(ab)
 
             // add contact1 to group
-            val batch = BatchOperation(ab.provider!!)
+            val batch = ContactsBatchOperation(ab.provider!!)
             contact1.addToGroup(batch, group.id!!)
             batch.commit()
 
@@ -164,7 +165,7 @@ class LocalGroupTest {
                 }
             )
 
-            group.clearDirty(null, null)
+            group.clearDirty(Optional.empty(), null)
 
             // check cached group membership
             ab.provider!!.query(
@@ -200,7 +201,7 @@ class LocalGroupTest {
                 }
             )
 
-            group.clearDirty(null, null)
+            group.clearDirty(Optional.empty(), null)
 
             // cached group membership should be gone
             ab.provider!!.query(
@@ -223,7 +224,7 @@ class LocalGroupTest {
                 LocalContact(ab, Contact().apply { displayName = "Test" }, "fn.vcf", null, 0)
             contact1.add()
 
-            val batch = BatchOperation(ab.provider!!)
+            val batch = ContactsBatchOperation(ab.provider!!)
             contact1.addToGroup(batch, group.id!!)
             batch.commit()
 

app/src/androidTest/kotlin/at/bitfire/davdroid/resource/LocalTestAddressBook.kt

@@ -10,7 +10,7 @@ import android.content.Context
 import at.bitfire.davdroid.repository.DavCollectionRepository
 import at.bitfire.davdroid.repository.DavServiceRepository
 import at.bitfire.davdroid.settings.AccountSettings
-import at.bitfire.davdroid.sync.SyncFrameworkIntegration
+import at.bitfire.davdroid.sync.adapter.SyncFrameworkIntegration
 import at.bitfire.vcard4android.GroupMethod
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory

app/src/androidTest/kotlin/at/bitfire/davdroid/servicedetection/CollectionListRefresherTest.kt

@@ -1,749 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.servicedetection
-
-import android.security.NetworkSecurityPolicy
-import at.bitfire.davdroid.db.AppDatabase
-import at.bitfire.davdroid.db.Collection
-import at.bitfire.davdroid.db.HomeSet
-import at.bitfire.davdroid.db.Principal
-import at.bitfire.davdroid.db.Service
-import at.bitfire.davdroid.network.HttpClient
-import at.bitfire.davdroid.settings.Settings
-import at.bitfire.davdroid.settings.SettingsManager
-import dagger.hilt.android.testing.BindValue
-import dagger.hilt.android.testing.HiltAndroidRule
-import dagger.hilt.android.testing.HiltAndroidTest
-import io.mockk.every
-import io.mockk.impl.annotations.MockK
-import io.mockk.junit4.MockKRule
-import kotlinx.coroutines.test.runTest
-import okhttp3.mockwebserver.Dispatcher
-import okhttp3.mockwebserver.MockResponse
-import okhttp3.mockwebserver.MockWebServer
-import okhttp3.mockwebserver.RecordedRequest
-import org.junit.After
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertTrue
-import org.junit.Assume
-import org.junit.Before
-import org.junit.Rule
-import org.junit.Test
-import java.util.logging.Logger
-import javax.inject.Inject
-
-@HiltAndroidTest
-class CollectionListRefresherTest {
-
-    @Inject
-    lateinit var db: AppDatabase
-
-    @Inject
-    lateinit var httpClientBuilder: HttpClient.Builder
-
-    @Inject
-    lateinit var logger: Logger
-
-    @Inject
-    lateinit var refresherFactory: CollectionListRefresher.Factory
-
-    @BindValue
-    @MockK(relaxed = true)
-    lateinit var settings: SettingsManager
-
-    @get:Rule
-    val hiltRule = HiltAndroidRule(this)
-
-    @get:Rule
-    val mockKRule = MockKRule(this)
-
-    private lateinit var client: HttpClient
-    private lateinit var mockServer: MockWebServer
-    private lateinit var service: Service
-
-    @Before
-    fun setUp() {
-        hiltRule.inject()
-
-        // Start mock web server
-        mockServer = MockWebServer().apply {
-            dispatcher = TestDispatcher(logger)
-            start()
-        }
-
-        // build HTTP client
-        client = httpClientBuilder.build()
-        Assume.assumeTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
-
-        // insert test service
-        val serviceId = db.serviceDao().insertOrReplace(
-            Service(id = 0, accountName = "test", type = Service.TYPE_CARDDAV, principal = null)
-        )
-        service = db.serviceDao().get(serviceId)!!
-    }
-
-    @After
-    fun tearDown() {
-        client.close()
-        mockServer.shutdown()
-    }
-
-
-    @Test
-    fun testDiscoverHomesets() {
-        val baseUrl = mockServer.url(PATH_CARDDAV + SUBPATH_PRINCIPAL)
-
-        // Query home sets
-        refresherFactory.create(service, client.okHttpClient).discoverHomesets(baseUrl)
-
-        // Check home set has been saved correctly to database
-        val savedHomesets = db.homeSetDao().getByService(service.id)
-        assertEquals(2, savedHomesets.size)
-
-        // Home set from current-user-principal
-        val personalHomeset = savedHomesets[1]
-        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL/"), personalHomeset.url)
-        assertEquals(service.id, personalHomeset.serviceId)
-        // personal should be true for homesets detected at first query of current-user-principal (Even if they occur in a group principal as well!!!)
-        assertEquals(true, personalHomeset.personal)
-
-        // Home set found in a group principal
-        val groupHomeset = savedHomesets[0]
-        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL/"), groupHomeset.url)
-        assertEquals(service.id, groupHomeset.serviceId)
-        // personal should be false for homesets not detected at the first query of current-user-principal (IE. in groups)
-        assertEquals(false, groupHomeset.personal)
-    }
-
-
-    // refreshHomesetsAndTheirCollections
-
-    @Test
-    fun refreshHomesetsAndTheirCollections_addsNewCollection() = runTest {
-        // save homeset in DB
-        val homesetId = db.homeSetDao().insert(
-            HomeSet(id=0, service.id, true, mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL"))
-        )
-
-        // Refresh
-        refresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
-
-        // Check the collection defined in homeset is now in the database
-        assertEquals(
-            Collection(
-                1,
-                service.id,
-                homesetId,
-                1, // will have gotten an owner too
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-                displayName = "My Contacts",
-                description = "My Contacts Description"
-            ),
-            db.collectionDao().getByService(service.id).first()
-        )
-    }
-
-    @Test
-    fun refreshHomesetsAndTheirCollections_updatesExistingCollection() {
-        // save "old" collection in DB
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-                displayName = "My Contacts",
-                description = "My Contacts Description"
-            )
-        )
-
-        // Refresh
-        refresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
-
-        // Check the collection got updated
-        assertEquals(
-            Collection(
-                collectionId,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-                displayName = "My Contacts",
-                description = "My Contacts Description"
-            ),
-            db.collectionDao().get(collectionId)
-        )
-    }
-
-    @Test
-    fun refreshHomesetsAndTheirCollections_preservesCollectionFlags() {
-        // save "old" collection in DB - with set flags
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-                displayName = "My Contacts",
-                description = "My Contacts Description",
-                forceReadOnly = true,
-                sync = true
-            )
-        )
-
-        // Refresh
-        refresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
-
-        // Check the collection got updated
-        assertEquals(
-            Collection(
-                collectionId,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-                displayName = "My Contacts",
-                description = "My Contacts Description",
-                forceReadOnly = true,
-                sync = true
-            ),
-            db.collectionDao().get(collectionId)
-        )
-    }
-
-    @Test
-    fun refreshHomesetsAndTheirCollections_marksRemovedCollectionsAsHomeless() {
-        // save homeset in DB - which is empty (zero address books) on the serverside
-        val homesetId = db.homeSetDao().insert(
-            HomeSet(id=0, service.id, true, mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_EMPTY"))
-        )
-
-        // place collection in DB - as part of the homeset
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                homesetId,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/")
-            )
-        )
-
-        // Refresh - should mark collection as homeless, because serverside homeset is empty.
-        refresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
-
-        // Check the collection, is now marked as homeless
-        assertEquals(null, db.collectionDao().get(collectionId)!!.homeSetId)
-    }
-
-    @Test
-    fun refreshHomesetsAndTheirCollections_addsOwnerUrls() {
-        // save a homeset in DB
-        val homesetId = db.homeSetDao().insert(
-            HomeSet(id=0, service.id, true, mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL"))
-        )
-
-        // place collection in DB - as part of the homeset
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                homesetId, // part of above home set
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/")
-            )
-        )
-
-        // Refresh - homesets and their collections
-        assertEquals(0, db.principalDao().getByService(service.id).size)
-        refresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
-
-        // Check principal saved and the collection was updated with its reference
-        val principals = db.principalDao().getByService(service.id)
-        assertEquals(1, principals.size)
-        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), principals[0].url)
-        assertEquals(null, principals[0].displayName)
-        assertEquals(
-            principals[0].id,
-            db.collectionDao().get(collectionId)!!.ownerId
-        )
-    }
-
-
-    // refreshHomelessCollections
-
-    @Test
-    fun refreshHomelessCollections_updatesExistingCollection() {
-        // place homeless collection in DB
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-            )
-        )
-
-        // Refresh
-        refresherFactory.create(service, client.okHttpClient).refreshHomelessCollections()
-
-        // Check the collection got updated - with display name and description
-        assertEquals(
-            Collection(
-                collectionId,
-                service.id,
-                null,
-                1, // will have gotten an owner too
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-                displayName = "My Contacts",
-                description = "My Contacts Description"
-            ),
-            db.collectionDao().get(collectionId)
-        )
-    }
-
-    @Test
-    fun refreshHomelessCollections_deletesInaccessibleCollections() {
-        // place homeless collection in DB - it is also inaccessible
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_INACCESSIBLE")
-            )
-        )
-
-        // Refresh - should delete collection
-        refresherFactory.create(service, client.okHttpClient).refreshHomelessCollections()
-
-        // Check the collection got deleted
-        assertEquals(null, db.collectionDao().get(collectionId))
-    }
-
-    @Test
-    fun refreshHomelessCollections_addsOwnerUrls() {
-        // place homeless collection in DB
-        val collectionId = db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                null,
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
-            )
-        )
-
-        // Refresh homeless collections
-        assertEquals(0, db.principalDao().getByService(service.id).size)
-        refresherFactory.create(service, client.okHttpClient).refreshHomelessCollections()
-
-        // Check principal saved and the collection was updated with its reference
-        val principals = db.principalDao().getByService(service.id)
-        assertEquals(1, principals.size)
-        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), principals[0].url)
-        assertEquals(null, principals[0].displayName)
-        assertEquals(
-            principals[0].id,
-            db.collectionDao().get(collectionId)!!.ownerId
-        )
-    }
-
-
-    // refreshPrincipals
-
-    @Test
-    fun refreshPrincipals_inaccessiblePrincipal() {
-        // place principal without display name in db
-        val principalId = db.principalDao().insert(
-            Principal(
-                0,
-                service.id,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL_INACCESSIBLE"), // no trailing slash
-                null // no display name for now
-            )
-        )
-        // add an associated collection - as the principal is rightfully removed otherwise
-        db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                principalId, // create association with principal
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"), // with trailing slash
-            )
-        )
-
-        // Refresh principals
-        refresherFactory.create(service, client.okHttpClient).refreshPrincipals()
-
-        // Check principal was not updated
-        val principals = db.principalDao().getByService(service.id)
-        assertEquals(1, principals.size)
-        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL_INACCESSIBLE"), principals[0].url)
-        assertEquals(null, principals[0].displayName)
-    }
-
-    @Test
-    fun refreshPrincipals_updatesPrincipal() {
-        // place principal without display name in db
-        val principalId = db.principalDao().insert(
-            Principal(
-                0,
-                service.id,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), // no trailing slash
-                null // no display name for now
-            )
-        )
-        // add an associated collection - as the principal is rightfully removed otherwise
-        db.collectionDao().insertOrUpdateByUrl(
-            Collection(
-                0,
-                service.id,
-                null,
-                principalId, // create association with principal
-                Collection.TYPE_ADDRESSBOOK,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"), // with trailing slash
-            )
-        )
-
-        // Refresh principals
-        refresherFactory.create(service, client.okHttpClient).refreshPrincipals()
-
-        // Check principal now got a display name
-        val principals = db.principalDao().getByService(service.id)
-        assertEquals(1, principals.size)
-        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), principals[0].url)
-        assertEquals("Mr. Wobbles", principals[0].displayName)
-    }
-
-    @Test
-    fun refreshPrincipals_deletesPrincipalsWithoutCollections() {
-        // place principal without collections in DB
-        db.principalDao().insert(
-            Principal(
-                0,
-                service.id,
-                mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL_WITHOUT_COLLECTIONS/")
-            )
-        )
-
-        // Refresh principals - detecting it does not own collections
-        refresherFactory.create(service, client.okHttpClient).refreshPrincipals()
-
-        // Check principal was deleted
-        val principals = db.principalDao().getByService(service.id)
-        assertEquals(0, principals.size)
-    }
-
-    // Others
-
-    @Test
-    fun shouldPreselect_none() {
-        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_NONE
-        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
-
-        val collection = Collection(
-            0,
-            service.id,
-            0,
-            type = Collection.TYPE_ADDRESSBOOK,
-            url = mockServer.url("/addressbook-homeset/addressbook/")
-        )
-        val homesets = listOf(
-            HomeSet(
-                id = 0,
-                serviceId = service.id,
-                personal = true,
-                url = mockServer.url("/addressbook-homeset/")
-            )
-        )
-
-        val refresher = refresherFactory.create(service, client.okHttpClient)
-        assertFalse(refresher.shouldPreselect(collection, homesets))
-    }
-
-    @Test
-    fun shouldPreselect_all() {
-        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_ALL
-        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
-
-        val collection = Collection(
-            0,
-            service.id,
-            0,
-            type = Collection.TYPE_ADDRESSBOOK,
-            url = mockServer.url("/addressbook-homeset/addressbook/")
-        )
-        val homesets = listOf(
-            HomeSet(
-                id = 0,
-                serviceId = service.id,
-                personal = false,
-                url = mockServer.url("/addressbook-homeset/")
-            )
-        )
-
-        val refresher = refresherFactory.create(service, client.okHttpClient)
-        assertTrue(refresher.shouldPreselect(collection, homesets))
-    }
-
-    @Test
-    fun shouldPreselect_all_blacklisted() {
-        val url = mockServer.url("/addressbook-homeset/addressbook/")
-
-        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_ALL
-        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns url.toString()
-
-        val collection = Collection(
-            id = 0,
-            serviceId = service.id,
-            homeSetId = 0,
-            type = Collection.TYPE_ADDRESSBOOK,
-            url = url
-        )
-        val homesets = listOf(
-            HomeSet(
-                id = 0,
-                serviceId = service.id,
-                personal = false,
-                url = mockServer.url("/addressbook-homeset/")
-            )
-        )
-
-        val refresher = refresherFactory.create(service, client.okHttpClient)
-        assertFalse(refresher.shouldPreselect(collection, homesets))
-    }
-
-    @Test
-    fun shouldPreselect_personal_notPersonal() {
-        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_PERSONAL
-        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
-
-        val collection = Collection(
-            id = 0,
-            serviceId = service.id,
-            homeSetId = 0,
-            type = Collection.TYPE_ADDRESSBOOK,
-            url = mockServer.url("/addressbook-homeset/addressbook/")
-        )
-        val homesets = listOf(
-            HomeSet(
-                id = 0,
-                serviceId = service.id,
-                personal = false,
-                url = mockServer.url("/addressbook-homeset/")
-            )
-        )
-
-        val refresher = refresherFactory.create(service, client.okHttpClient)
-        assertFalse(refresher.shouldPreselect(collection, homesets))
-    }
-
-    @Test
-    fun shouldPreselect_personal_isPersonal() {
-        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_PERSONAL
-        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
-
-        val collection = Collection(
-            0,
-            service.id,
-            0,
-            type = Collection.TYPE_ADDRESSBOOK,
-            url = mockServer.url("/addressbook-homeset/addressbook/")
-        )
-        val homesets = listOf(
-            HomeSet(
-                id = 0,
-                serviceId = service.id,
-                personal = true,
-                url = mockServer.url("/addressbook-homeset/")
-            )
-        )
-
-        val refresher = refresherFactory.create(service, client.okHttpClient)
-        assertTrue(refresher.shouldPreselect(collection, homesets))
-    }
-
-    @Test
-    fun shouldPreselect_personal_isPersonalButBlacklisted() {
-        val collectionUrl = mockServer.url("/addressbook-homeset/addressbook/")
-
-        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_PERSONAL
-        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns collectionUrl.toString()
-
-        val collection = Collection(
-            id = 0,
-            serviceId = service.id,
-            homeSetId = 0,
-            type = Collection.TYPE_ADDRESSBOOK,
-            url = collectionUrl
-        )
-        val homesets = listOf(
-            HomeSet(
-                id = 0,
-                serviceId = service.id,
-                personal = true,
-                url = mockServer.url("/addressbook-homeset/")
-            )
-        )
-
-        val refresher = refresherFactory.create(service, client.okHttpClient)
-        assertFalse(refresher.shouldPreselect(collection, homesets))
-    }
-
-
-    companion object {
-
-        private const val PATH_CALDAV = "/caldav"
-        private const val PATH_CARDDAV = "/carddav"
-
-        private const val SUBPATH_PRINCIPAL = "/principal"
-        private const val SUBPATH_PRINCIPAL_INACCESSIBLE = "/inaccessible-principal"
-        private const val SUBPATH_PRINCIPAL_WITHOUT_COLLECTIONS = "/principal2"
-        private const val SUBPATH_GROUPPRINCIPAL_0 = "/groups/0"
-        private const val SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL = "/addressbooks-homeset"
-        private const val SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL = "/addressbooks-homeset-non-personal"
-        private const val SUBPATH_ADDRESSBOOK_HOMESET_EMPTY = "/addressbooks-homeset-empty"
-        private const val SUBPATH_ADDRESSBOOK = "/addressbooks/my-contacts"
-        private const val SUBPATH_ADDRESSBOOK_INACCESSIBLE = "/addressbooks/inaccessible-contacts"
-
-    }
-
-    class TestDispatcher(
-        private val logger: Logger
-    ): Dispatcher() {
-
-        override fun dispatch(request: RecordedRequest): MockResponse {
-            val path = request.path!!.trimEnd('/')
-
-            if (request.method.equals("PROPFIND", true)) {
-                val properties = when (path) {
-                    PATH_CALDAV,
-                    PATH_CARDDAV ->
-                        "<current-user-principal>" +
-                        "   <href>$path${SUBPATH_PRINCIPAL}</href>" +
-                        "</current-user-principal>"
-
-                    PATH_CARDDAV + SUBPATH_PRINCIPAL ->
-                        "<resourcetype><principal/></resourcetype>" +
-                        "<displayname>Mr. Wobbles</displayname>" +
-                        "<CARD:addressbook-home-set>" +
-                        "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL}</href>" +
-                        "</CARD:addressbook-home-set>" +
-                        "<group-membership>" +
-                        "   <href>${PATH_CARDDAV}${SUBPATH_GROUPPRINCIPAL_0}</href>" +
-                        "</group-membership>"
-
-                    PATH_CARDDAV + SUBPATH_PRINCIPAL_WITHOUT_COLLECTIONS ->
-                        "<CARD:addressbook-home-set>" +
-                        "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_EMPTY}</href>" +
-                        "</CARD:addressbook-home-set>" +
-                        "<displayname>Mr. Wobbles Jr.</displayname>"
-
-                    PATH_CARDDAV + SUBPATH_GROUPPRINCIPAL_0 ->
-                        "<resourcetype><principal/></resourcetype>" +
-                        "<displayname>All address books</displayname>" +
-                        "<CARD:addressbook-home-set>" +
-                        "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL}</href>" +
-                        "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL}</href>" +
-                        "</CARD:addressbook-home-set>"
-
-                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK,
-                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL ->
-                        "<resourcetype>" +
-                        "   <collection/>" +
-                        "   <CARD:addressbook/>" +
-                        "</resourcetype>" +
-                        "<displayname>My Contacts</displayname>" +
-                        "<CARD:addressbook-description>My Contacts Description</CARD:addressbook-description>" +
-                        "<owner>" +
-                        "   <href>${PATH_CARDDAV + SUBPATH_PRINCIPAL}</href>" +
-                        "</owner>"
-
-                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL ->
-                        "<resourcetype>" +
-                        "   <collection/>" +
-                        "   <CARD:addressbook/>" +
-                        "</resourcetype>" +
-                        "<displayname>Freds Contacts (not mine)</displayname>" +
-                        "<CARD:addressbook-description>Not personal contacts</CARD:addressbook-description>" +
-                        "<owner>" +
-                        "   <href>${PATH_CARDDAV + SUBPATH_PRINCIPAL}</href>" + // OK, user is allowed to own non-personal contacts
-                        "</owner>"
-
-                    PATH_CALDAV + SUBPATH_PRINCIPAL ->
-                        "<CAL:calendar-user-address-set>" +
-                        "  <href>urn:unknown-entry</href>" +
-                        "  <href>mailto:email1@example.com</href>" +
-                        "  <href>mailto:email2@example.com</href>" +
-                        "</CAL:calendar-user-address-set>"
-
-                    SUBPATH_ADDRESSBOOK_HOMESET_EMPTY -> ""
-
-                    else -> ""
-                }
-
-                var responseBody = ""
-                var responseCode = 207
-                when (path) {
-                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL ->
-                        responseBody =
-                            "<multistatus xmlns='DAV:' xmlns:CARD='urn:ietf:params:xml:ns:carddav' xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
-                            "<response>" +
-                            "   <href>${PATH_CARDDAV + SUBPATH_ADDRESSBOOK}</href>" +
-                            "   <propstat><prop>" +
-                                    properties +
-                            "   </prop></propstat>" +
-                            "   <status>HTTP/1.1 200 OK</status>" +
-                            "</response>" +
-                            "</multistatus>"
-
-                    PATH_CARDDAV + SUBPATH_PRINCIPAL_INACCESSIBLE,
-                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK_INACCESSIBLE ->
-                        responseCode = 404
-
-                    else ->
-                        responseBody =
-                            "<multistatus xmlns='DAV:' xmlns:CARD='urn:ietf:params:xml:ns:carddav' xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
-                            "<response>" +
-                            "   <href>$path</href>" +
-                            "   <propstat><prop>"+
-                                    properties +
-                            "   </prop></propstat>" +
-                            "</response>" +
-                            "</multistatus>"
-                }
-
-                logger.info("Queried: $path")
-                logger.info("Response: $responseBody")
-                return MockResponse()
-                    .setResponseCode(responseCode)
-                    .setBody(responseBody)
-            }
-
-            return MockResponse().setResponseCode(404)
-        }
-
-    }
-
-}

app/src/androidTest/kotlin/at/bitfire/davdroid/servicedetection/CollectionsWithoutHomeSetRefresherTest.kt

@@ -0,0 +1,222 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import android.security.NetworkSecurityPolicy
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Collection
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.network.HttpClient
+import at.bitfire.davdroid.settings.SettingsManager
+import dagger.hilt.android.testing.BindValue
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import io.mockk.impl.annotations.MockK
+import io.mockk.junit4.MockKRule
+import okhttp3.mockwebserver.Dispatcher
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import okhttp3.mockwebserver.RecordedRequest
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assume
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.logging.Logger
+import javax.inject.Inject
+
+@HiltAndroidTest
+class CollectionsWithoutHomeSetRefresherTest {
+
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @get:Rule
+    val mockKRule = MockKRule(this)
+
+    @Inject
+    lateinit var db: AppDatabase
+
+    @Inject
+    lateinit var httpClientBuilder: HttpClient.Builder
+
+    @Inject
+    lateinit var logger: Logger
+
+    @Inject
+    lateinit var refresherFactory: CollectionsWithoutHomeSetRefresher.Factory
+
+    @BindValue
+    @MockK(relaxed = true)
+    lateinit var settings: SettingsManager
+
+    private lateinit var client: HttpClient
+    private lateinit var mockServer: MockWebServer
+    private lateinit var service: Service
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+
+        // Start mock web server
+        mockServer = MockWebServer().apply {
+            dispatcher = TestDispatcher(logger)
+            start()
+        }
+
+        // build HTTP client
+        client = httpClientBuilder.build()
+        Assume.assumeTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
+
+        // insert test service
+        val serviceId = db.serviceDao().insertOrReplace(
+            Service(id = 0, accountName = "test", type = Service.TYPE_CARDDAV, principal = null)
+        )
+        service = db.serviceDao().get(serviceId)!!
+    }
+
+    @After
+    fun tearDown() {
+        client.close()
+        mockServer.shutdown()
+    }
+
+
+    // refreshCollectionsWithoutHomeSet
+
+    @Test
+    fun refreshCollectionsWithoutHomeSet_updatesExistingCollection() {
+        // place homeless collection in DB
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+            )
+        )
+
+        // Refresh
+        refresherFactory.create(service, client.okHttpClient).refreshCollectionsWithoutHomeSet()
+
+        // Check the collection got updated - with display name and description
+        assertEquals(
+            Collection(
+                collectionId,
+                service.id,
+                null,
+                1, // will have gotten an owner too
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+                displayName = "My Contacts",
+                description = "My Contacts Description"
+            ),
+            db.collectionDao().get(collectionId)
+        )
+    }
+
+    @Test
+    fun refreshCollectionsWithoutHomeSet_deletesInaccessibleCollectionsWithoutHomeSet() {
+        // place homeless collection in DB - it is also inaccessible
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_INACCESSIBLE")
+            )
+        )
+
+        // Refresh - should delete collection
+        refresherFactory.create(service, client.okHttpClient).refreshCollectionsWithoutHomeSet()
+
+        // Check the collection got deleted
+        assertEquals(null, db.collectionDao().get(collectionId))
+    }
+
+    @Test
+    fun refreshCollectionsWithoutHomeSet_addsOwnerUrls() {
+        // place homeless collection in DB
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+            )
+        )
+
+        // Refresh homeless collections
+        assertEquals(0, db.principalDao().getByService(service.id).size)
+        refresherFactory.create(service, client.okHttpClient).refreshCollectionsWithoutHomeSet()
+
+        // Check principal saved and the collection was updated with its reference
+        val principals = db.principalDao().getByService(service.id)
+        assertEquals(1, principals.size)
+        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), principals[0].url)
+        assertEquals(null, principals[0].displayName)
+        assertEquals(
+            principals[0].id,
+            db.collectionDao().get(collectionId)!!.ownerId
+        )
+    }
+
+
+    companion object {
+        private const val PATH_CARDDAV = "/carddav"
+        private const val SUBPATH_PRINCIPAL = "/principal"
+        private const val SUBPATH_ADDRESSBOOK = "/addressbooks/my-contacts"
+        private const val SUBPATH_ADDRESSBOOK_INACCESSIBLE = "/addressbooks/inaccessible-contacts"
+    }
+
+    class TestDispatcher(
+        private val logger: Logger
+    ): Dispatcher() {
+
+        override fun dispatch(request: RecordedRequest): MockResponse {
+            val path = request.path!!.trimEnd('/')
+            logger.info("${request.method} on $path")
+
+            if (request.method.equals("PROPFIND", true)) {
+                val properties = when (path) {
+                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK ->
+                        "<resourcetype>" +
+                        "   <collection/>" +
+                        "   <CARD:addressbook/>" +
+                        "</resourcetype>" +
+                        "<displayname>My Contacts</displayname>" +
+                        "<CARD:addressbook-description>My Contacts Description</CARD:addressbook-description>" +
+                        "<owner>" +
+                        "   <href>${PATH_CARDDAV + SUBPATH_PRINCIPAL}</href>" +
+                        "</owner>"
+
+                    else -> ""
+                }
+
+                return MockResponse()
+                    .setResponseCode(207)
+                    .setBody("<multistatus xmlns='DAV:' xmlns:CARD='urn:ietf:params:xml:ns:carddav' xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
+                            "<response>" +
+                            "   <href>$path</href>" +
+                            "   <propstat><prop>"+
+                            properties +
+                            "   </prop></propstat>" +
+                            "</response>" +
+                            "</multistatus>")
+            }
+
+            return MockResponse().setResponseCode(404)
+        }
+
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/servicedetection/DavResourceFinderTest.kt

@@ -8,9 +8,9 @@ import android.security.NetworkSecurityPolicy
 import at.bitfire.dav4jvm.DavResource
 import at.bitfire.dav4jvm.property.carddav.AddressbookHomeSet
 import at.bitfire.dav4jvm.property.webdav.ResourceType
-import at.bitfire.davdroid.db.Credentials
 import at.bitfire.davdroid.network.HttpClient
 import at.bitfire.davdroid.servicedetection.DavResourceFinder.Configuration.ServiceInfo
+import at.bitfire.davdroid.settings.Credentials
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import okhttp3.mockwebserver.Dispatcher
@@ -72,7 +72,7 @@ class DavResourceFinderTest {
 
         val credentials = Credentials(username = "mock", password = "12345".toCharArray())
         client = httpClientBuilder
-                .authenticate(host = null, credentials = credentials)
+                .authenticate(host = null, getCredentials = { credentials })
                 .build()
         Assume.assumeTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
 

app/src/androidTest/kotlin/at/bitfire/davdroid/servicedetection/HomeSetRefresherTest.kt

@@ -0,0 +1,473 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import android.security.NetworkSecurityPolicy
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Collection
+import at.bitfire.davdroid.db.HomeSet
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.network.HttpClient
+import at.bitfire.davdroid.settings.Settings
+import at.bitfire.davdroid.settings.SettingsManager
+import dagger.hilt.android.testing.BindValue
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import io.mockk.every
+import io.mockk.impl.annotations.MockK
+import io.mockk.junit4.MockKRule
+import junit.framework.TestCase.assertFalse
+import junit.framework.TestCase.assertTrue
+import kotlinx.coroutines.test.runTest
+import okhttp3.mockwebserver.Dispatcher
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import okhttp3.mockwebserver.RecordedRequest
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assume
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.logging.Logger
+import javax.inject.Inject
+
+@HiltAndroidTest
+class HomeSetRefresherTest {
+
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @get:Rule
+    val mockKRule = MockKRule(this)
+
+    @Inject
+    lateinit var db: AppDatabase
+
+    @Inject
+    lateinit var httpClientBuilder: HttpClient.Builder
+
+    @Inject
+    lateinit var logger: Logger
+
+    @Inject
+    lateinit var homeSetRefresherFactory: HomeSetRefresher.Factory
+
+    @BindValue
+    @MockK(relaxed = true)
+    lateinit var settings: SettingsManager
+
+    private lateinit var client: HttpClient
+    private lateinit var mockServer: MockWebServer
+    private lateinit var service: Service
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+
+        // Start mock web server
+        mockServer = MockWebServer().apply {
+            dispatcher = TestDispatcher(logger)
+            start()
+        }
+
+        // build HTTP client
+        client = httpClientBuilder.build()
+        Assume.assumeTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
+
+        // insert test service
+        val serviceId = db.serviceDao().insertOrReplace(
+            Service(id = 0, accountName = "test", type = Service.TYPE_CARDDAV, principal = null)
+        )
+        service = db.serviceDao().get(serviceId)!!
+    }
+
+    @After
+    fun tearDown() {
+        client.close()
+        mockServer.shutdown()
+    }
+
+
+    // refreshHomesetsAndTheirCollections
+
+    @Test
+    fun refreshHomesetsAndTheirCollections_addsNewCollection() = runTest {
+        // save homeset in DB
+        val homesetId = db.homeSetDao().insert(
+            HomeSet(id = 0, service.id, true, mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL"))
+        )
+
+        // Refresh
+        homeSetRefresherFactory.create(service, client.okHttpClient)
+            .refreshHomesetsAndTheirCollections()
+
+        // Check the collection defined in homeset is now in the database
+        assertEquals(
+            Collection(
+                1,
+                service.id,
+                homesetId,
+                1, // will have gotten an owner too
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+                displayName = "My Contacts",
+                description = "My Contacts Description"
+            ),
+            db.collectionDao().getByService(service.id).first()
+        )
+    }
+
+    @Test
+    fun refreshHomesetsAndTheirCollections_updatesExistingCollection() {
+        // save "old" collection in DB
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+                displayName = "My Contacts",
+                description = "My Contacts Description"
+            )
+        )
+
+        // Refresh
+        homeSetRefresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
+
+        // Check the collection got updated
+        assertEquals(
+            Collection(
+                collectionId,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+                displayName = "My Contacts",
+                description = "My Contacts Description"
+            ),
+            db.collectionDao().get(collectionId)
+        )
+    }
+
+    @Test
+    fun refreshHomesetsAndTheirCollections_preservesCollectionFlags() {
+        // save "old" collection in DB - with set flags
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+                displayName = "My Contacts",
+                description = "My Contacts Description",
+                forceReadOnly = true,
+                sync = true
+            )
+        )
+
+        // Refresh
+        homeSetRefresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
+
+        // Check the collection got updated
+        assertEquals(
+            Collection(
+                collectionId,
+                service.id,
+                null,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"),
+                displayName = "My Contacts",
+                description = "My Contacts Description",
+                forceReadOnly = true,
+                sync = true
+            ),
+            db.collectionDao().get(collectionId)
+        )
+    }
+
+    @Test
+    fun refreshHomesetsAndTheirCollections_marksRemovedCollectionsAsHomeless() {
+        // save homeset in DB - which is empty (zero address books) on the serverside
+        val homesetId = db.homeSetDao().insert(
+            HomeSet(id = 0, service.id, true, mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_EMPTY"))
+        )
+
+        // place collection in DB - as part of the homeset
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                homesetId,
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/")
+            )
+        )
+
+        // Refresh - should mark collection as homeless, because serverside homeset is empty.
+        homeSetRefresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
+
+        // Check the collection, is now marked as homeless
+        assertEquals(null, db.collectionDao().get(collectionId)!!.homeSetId)
+    }
+
+    @Test
+    fun refreshHomesetsAndTheirCollections_addsOwnerUrls() {
+        // save a homeset in DB
+        val homesetId = db.homeSetDao().insert(
+            HomeSet(id = 0, service.id, true, mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL"))
+        )
+
+        // place collection in DB - as part of the homeset
+        val collectionId = db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                homesetId, // part of above home set
+                null,
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/")
+            )
+        )
+
+        // Refresh - homesets and their collections
+        assertEquals(0, db.principalDao().getByService(service.id).size)
+        homeSetRefresherFactory.create(service, client.okHttpClient).refreshHomesetsAndTheirCollections()
+
+        // Check principal saved and the collection was updated with its reference
+        val principals = db.principalDao().getByService(service.id)
+        assertEquals(1, principals.size)
+        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), principals[0].url)
+        assertEquals(null, principals[0].displayName)
+        assertEquals(
+            principals[0].id,
+            db.collectionDao().get(collectionId)!!.ownerId
+        )
+    }
+
+
+    // other
+
+    @Test
+    fun shouldPreselect_none() {
+        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_NONE
+        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
+
+        val collection = Collection(
+            0,
+            service.id,
+            0,
+            type = Collection.TYPE_ADDRESSBOOK,
+            url = mockServer.url("/addressbook-homeset/addressbook/")
+        )
+        val homesets = listOf(
+            HomeSet(
+                id = 0,
+                serviceId = service.id,
+                personal = true,
+                url = mockServer.url("/addressbook-homeset/")
+            )
+        )
+
+        val refresher = homeSetRefresherFactory.create(service, client.okHttpClient)
+        assertFalse(refresher.shouldPreselect(collection, homesets))
+    }
+
+    @Test
+    fun shouldPreselect_all() {
+        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_ALL
+        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
+
+        val collection = Collection(
+            0,
+            service.id,
+            0,
+            type = Collection.TYPE_ADDRESSBOOK,
+            url = mockServer.url("/addressbook-homeset/addressbook/")
+        )
+        val homesets = listOf(
+            HomeSet(
+                id = 0,
+                serviceId = service.id,
+                personal = false,
+                url = mockServer.url("/addressbook-homeset/")
+            )
+        )
+
+        val refresher = homeSetRefresherFactory.create(service, client.okHttpClient)
+        assertTrue(refresher.shouldPreselect(collection, homesets))
+    }
+
+    @Test
+    fun shouldPreselect_all_blacklisted() {
+        val url = mockServer.url("/addressbook-homeset/addressbook/")
+
+        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_ALL
+        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns url.toString()
+
+        val collection = Collection(
+            id = 0,
+            serviceId = service.id,
+            homeSetId = 0,
+            type = Collection.TYPE_ADDRESSBOOK,
+            url = url
+        )
+        val homesets = listOf(
+            HomeSet(
+                id = 0,
+                serviceId = service.id,
+                personal = false,
+                url = mockServer.url("/addressbook-homeset/")
+            )
+        )
+
+        val refresher = homeSetRefresherFactory.create(service, client.okHttpClient)
+        assertFalse(refresher.shouldPreselect(collection, homesets))
+    }
+
+    @Test
+    fun shouldPreselect_personal_notPersonal() {
+        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_PERSONAL
+        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
+
+        val collection = Collection(
+            id = 0,
+            serviceId = service.id,
+            homeSetId = 0,
+            type = Collection.TYPE_ADDRESSBOOK,
+            url = mockServer.url("/addressbook-homeset/addressbook/")
+        )
+        val homesets = listOf(
+            HomeSet(
+                id = 0,
+                serviceId = service.id,
+                personal = false,
+                url = mockServer.url("/addressbook-homeset/")
+            )
+        )
+
+        val refresher = homeSetRefresherFactory.create(service, client.okHttpClient)
+        assertFalse(refresher.shouldPreselect(collection, homesets))
+    }
+
+    @Test
+    fun shouldPreselect_personal_isPersonal() {
+        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_PERSONAL
+        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns ""
+
+        val collection = Collection(
+            0,
+            service.id,
+            0,
+            type = Collection.TYPE_ADDRESSBOOK,
+            url = mockServer.url("/addressbook-homeset/addressbook/")
+        )
+        val homesets = listOf(
+            HomeSet(
+                id = 0,
+                serviceId = service.id,
+                personal = true,
+                url = mockServer.url("/addressbook-homeset/")
+            )
+        )
+
+        val refresher = homeSetRefresherFactory.create(service, client.okHttpClient)
+        assertTrue(refresher.shouldPreselect(collection, homesets))
+    }
+
+    @Test
+    fun shouldPreselect_personal_isPersonalButBlacklisted() {
+        val collectionUrl = mockServer.url("/addressbook-homeset/addressbook/")
+
+        every { settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS) } returns Settings.PRESELECT_COLLECTIONS_PERSONAL
+        every { settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED) } returns collectionUrl.toString()
+
+        val collection = Collection(
+            id = 0,
+            serviceId = service.id,
+            homeSetId = 0,
+            type = Collection.TYPE_ADDRESSBOOK,
+            url = collectionUrl
+        )
+        val homesets = listOf(
+            HomeSet(
+                id = 0,
+                serviceId = service.id,
+                personal = true,
+                url = mockServer.url("/addressbook-homeset/")
+            )
+        )
+
+        val refresher = homeSetRefresherFactory.create(service, client.okHttpClient)
+        assertFalse(refresher.shouldPreselect(collection, homesets))
+    }
+
+
+    companion object {
+
+        private const val PATH_CARDDAV = "/carddav"
+
+        private const val SUBPATH_PRINCIPAL = "/principal"
+        private const val SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL = "/addressbooks-homeset"
+        private const val SUBPATH_ADDRESSBOOK_HOMESET_EMPTY = "/addressbooks-homeset-empty"
+        private const val SUBPATH_ADDRESSBOOK = "/addressbooks/my-contacts"
+
+    }
+
+    class TestDispatcher(
+        private val logger: Logger
+    ) : Dispatcher() {
+
+        override fun dispatch(request: RecordedRequest): MockResponse {
+            val path = request.path!!.trimEnd('/')
+
+            if (request.method.equals("PROPFIND", true)) {
+                val properties = when (path) {
+
+                    PATH_CARDDAV + SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL ->
+                        "<resourcetype>" +
+                                "   <collection/>" +
+                                "   <CARD:addressbook/>" +
+                                "</resourcetype>" +
+                                "<displayname>My Contacts</displayname>" +
+                                "<CARD:addressbook-description>My Contacts Description</CARD:addressbook-description>" +
+                                "<owner>" +
+                                "   <href>${PATH_CARDDAV + SUBPATH_PRINCIPAL}</href>" +
+                                "</owner>"
+
+                    SUBPATH_ADDRESSBOOK_HOMESET_EMPTY -> ""
+
+                    else -> ""
+                }
+
+                logger.info("Queried: $path")
+                return MockResponse()
+                    .setResponseCode(207)
+                    .setBody(
+                        "<multistatus xmlns='DAV:' xmlns:CARD='urn:ietf:params:xml:ns:carddav' xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
+                                "<response>" +
+                                "   <href>${PATH_CARDDAV + SUBPATH_ADDRESSBOOK}</href>" +
+                                "   <propstat><prop>" +
+                                properties +
+                                "   </prop></propstat>" +
+                                "   <status>HTTP/1.1 200 OK</status>" +
+                                "</response>" +
+                                "</multistatus>"
+                    )
+            }
+
+            return MockResponse().setResponseCode(404)
+        }
+
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/servicedetection/PrincipalsRefresherTest.kt

@@ -0,0 +1,236 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import android.security.NetworkSecurityPolicy
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Collection
+import at.bitfire.davdroid.db.Principal
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.network.HttpClient
+import at.bitfire.davdroid.settings.SettingsManager
+import dagger.hilt.android.testing.BindValue
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import io.mockk.impl.annotations.MockK
+import io.mockk.junit4.MockKRule
+import junit.framework.TestCase.assertEquals
+import okhttp3.mockwebserver.Dispatcher
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import okhttp3.mockwebserver.RecordedRequest
+import org.junit.After
+import org.junit.Assume
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.logging.Logger
+import javax.inject.Inject
+
+@HiltAndroidTest
+class PrincipalsRefresherTest {
+
+    @Inject
+    lateinit var db: AppDatabase
+
+    @Inject
+    lateinit var httpClientBuilder: HttpClient.Builder
+
+    @Inject
+    lateinit var logger: Logger
+
+    @Inject
+    lateinit var principalsRefresher: PrincipalsRefresher.Factory
+
+    @BindValue
+    @MockK(relaxed = true)
+    lateinit var settings: SettingsManager
+
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @get:Rule
+    val mockKRule = MockKRule(this)
+
+    private lateinit var client: HttpClient
+    private lateinit var mockServer: MockWebServer
+    private lateinit var service: Service
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+
+        // Start mock web server
+        mockServer = MockWebServer().apply {
+            dispatcher = TestDispatcher(logger)
+            start()
+        }
+
+        // build HTTP client
+        client = httpClientBuilder.build()
+        Assume.assumeTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
+
+        // insert test service
+        val serviceId = db.serviceDao().insertOrReplace(
+            Service(id = 0, accountName = "test", type = Service.TYPE_CARDDAV, principal = null)
+        )
+        service = db.serviceDao().get(serviceId)!!
+    }
+
+    @After
+    fun tearDown() {
+        client.close()
+        mockServer.shutdown()
+    }
+
+
+    @Test
+    fun refreshPrincipals_inaccessiblePrincipal() {
+        // place principal without display name in db
+        val principalId = db.principalDao().insert(
+            Principal(
+                0,
+                service.id,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL_INACCESSIBLE"), // no trailing slash
+                null // no display name for now
+            )
+        )
+        // add an associated collection - as the principal is rightfully removed otherwise
+        db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                principalId, // create association with principal
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"), // with trailing slash
+            )
+        )
+
+        // Refresh principals
+        principalsRefresher.create(service, client.okHttpClient).refreshPrincipals()
+
+        // Check principal was not updated
+        val principals = db.principalDao().getByService(service.id)
+        assertEquals(1, principals.size)
+        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL_INACCESSIBLE"), principals[0].url)
+        assertEquals(null, principals[0].displayName)
+    }
+
+    @Test
+    fun refreshPrincipals_updatesPrincipal() {
+        // place principal without display name in db
+        val principalId = db.principalDao().insert(
+            Principal(
+                0,
+                service.id,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), // no trailing slash
+                null // no display name for now
+            )
+        )
+        // add an associated collection - as the principal is rightfully removed otherwise
+        db.collectionDao().insertOrUpdateByUrl(
+            Collection(
+                0,
+                service.id,
+                null,
+                principalId, // create association with principal
+                Collection.TYPE_ADDRESSBOOK,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK/"), // with trailing slash
+            )
+        )
+
+        // Refresh principals
+        principalsRefresher.create(service, client.okHttpClient).refreshPrincipals()
+
+        // Check principal now got a display name
+        val principals = db.principalDao().getByService(service.id)
+        assertEquals(1, principals.size)
+        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL"), principals[0].url)
+        assertEquals("Mr. Wobbles", principals[0].displayName)
+    }
+
+    @Test
+    fun refreshPrincipals_deletesPrincipalsWithoutCollections() {
+        // place principal without collections in DB
+        db.principalDao().insert(
+            Principal(
+                0,
+                service.id,
+                mockServer.url("$PATH_CARDDAV$SUBPATH_PRINCIPAL_WITHOUT_COLLECTIONS/")
+            )
+        )
+
+        // Refresh principals - detecting it does not own collections
+        principalsRefresher.create(service, client.okHttpClient).refreshPrincipals()
+
+        // Check principal was deleted
+        val principals = db.principalDao().getByService(service.id)
+        assertEquals(0, principals.size)
+    }
+
+
+    companion object {
+
+        private const val PATH_CARDDAV = "/carddav"
+
+        private const val SUBPATH_PRINCIPAL = "/principal"
+        private const val SUBPATH_PRINCIPAL_INACCESSIBLE = "/inaccessible-principal"
+        private const val SUBPATH_PRINCIPAL_WITHOUT_COLLECTIONS = "/principal2"
+        private const val SUBPATH_GROUPPRINCIPAL_0 = "/groups/0"
+        private const val SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL = "/addressbooks-homeset"
+        private const val SUBPATH_ADDRESSBOOK_HOMESET_EMPTY = "/addressbooks-homeset-empty"
+        private const val SUBPATH_ADDRESSBOOK = "/addressbooks/my-contacts"
+
+    }
+
+    class TestDispatcher(
+        private val logger: Logger
+    ) : Dispatcher() {
+
+        override fun dispatch(request: RecordedRequest): MockResponse {
+            val path = request.path!!.trimEnd('/')
+
+            if (request.method.equals("PROPFIND", true)) {
+                val properties = when (path) {
+
+                    PATH_CARDDAV + SUBPATH_PRINCIPAL ->
+                        "<resourcetype><principal/></resourcetype>" +
+                                "<displayname>Mr. Wobbles</displayname>" + "<CARD:addressbook-home-set>" + "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL}</href>" + "</CARD:addressbook-home-set>" + "<group-membership>" + "   <href>${PATH_CARDDAV}${SUBPATH_GROUPPRINCIPAL_0}</href>" +
+                                "</group-membership>"
+
+                    PATH_CARDDAV + SUBPATH_PRINCIPAL_WITHOUT_COLLECTIONS ->
+                        "<CARD:addressbook-home-set>" +
+                                "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_EMPTY}</href>" +
+                                "</CARD:addressbook-home-set>" +
+                                "<displayname>Mr. Wobbles Jr.</displayname>"
+
+
+                    SUBPATH_ADDRESSBOOK_HOMESET_EMPTY -> ""
+
+                    else -> ""
+                }
+
+                logger.info("Queried: $path")
+                return MockResponse()
+                    .setResponseCode(207)
+                    .setBody(
+                        "<multistatus xmlns='DAV:' xmlns:CARD='urn:ietf:params:xml:ns:carddav' xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
+                                "<response>" +
+                                "   <href>$path</href>" +
+                                "   <propstat><prop>" +
+                                properties +
+                                "   </prop></propstat>" +
+                                "</response>" +
+                                "</multistatus>"
+                    )
+            }
+
+            return MockResponse().setResponseCode(404)
+        }
+
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/servicedetection/ServiceRefresherTest.kt

@@ -0,0 +1,163 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import android.security.NetworkSecurityPolicy
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.network.HttpClient
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import okhttp3.mockwebserver.Dispatcher
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import okhttp3.mockwebserver.RecordedRequest
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assume
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.logging.Logger
+import javax.inject.Inject
+
+@HiltAndroidTest
+class ServiceRefresherTest {
+
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @Inject
+    lateinit var db: AppDatabase
+
+    @Inject
+    lateinit var httpClientBuilder: HttpClient.Builder
+
+    @Inject
+    lateinit var logger: Logger
+
+    @Inject
+    lateinit var serviceRefresherFactory: ServiceRefresher.Factory
+
+    private lateinit var client: HttpClient
+    private lateinit var mockServer: MockWebServer
+    private lateinit var service: Service
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+
+        // Start mock web server
+        mockServer = MockWebServer().apply {
+            dispatcher = TestDispatcher(logger)
+            start()
+        }
+
+        // build HTTP client
+        client = httpClientBuilder.build()
+        Assume.assumeTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
+
+        // insert test service
+        val serviceId = db.serviceDao().insertOrReplace(
+            Service(id = 0, accountName = "test", type = Service.TYPE_CARDDAV, principal = null)
+        )
+        service = db.serviceDao().get(serviceId)!!
+    }
+
+    @After
+    fun tearDown() {
+        client.close()
+        mockServer.shutdown()
+    }
+
+
+    @Test
+    fun testDiscoverHomesets() {
+        val baseUrl = mockServer.url(PATH_CARDDAV + SUBPATH_PRINCIPAL)
+
+        // Query home sets
+        serviceRefresherFactory.create(service, client.okHttpClient)
+            .discoverHomesets(baseUrl)
+
+        // Check home set has been saved correctly to database
+        val savedHomesets = db.homeSetDao().getByService(service.id)
+        assertEquals(2, savedHomesets.size)
+
+        // Home set from current-user-principal
+        val personalHomeset = savedHomesets[1]
+        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL/"), personalHomeset.url)
+        assertEquals(service.id, personalHomeset.serviceId)
+        // personal should be true for homesets detected at first query of current-user-principal (Even if they occur in a group principal as well!!!)
+        assertEquals(true, personalHomeset.personal)
+
+        // Home set found in a group principal
+        val groupHomeset = savedHomesets[0]
+        assertEquals(mockServer.url("$PATH_CARDDAV$SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL/"), groupHomeset.url)
+        assertEquals(service.id, groupHomeset.serviceId)
+        // personal should be false for homesets not detected at the first query of current-user-principal (IE. in groups)
+        assertEquals(false, groupHomeset.personal)
+    }
+
+
+    companion object {
+        private const val PATH_CARDDAV = "/carddav"
+
+        private const val SUBPATH_PRINCIPAL = "/principal"
+        private const val SUBPATH_GROUPPRINCIPAL_0 = "/groups/0"
+        private const val SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL = "/addressbooks-homeset"
+        private const val SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL = "/addressbooks-homeset-non-personal"
+
+    }
+
+    class TestDispatcher(
+        private val logger: Logger
+    ) : Dispatcher() {
+
+        override fun dispatch(request: RecordedRequest): MockResponse {
+            val path = request.path!!.trimEnd('/')
+            logger.info("Query: ${request.method} on $path ")
+
+            if (request.method.equals("PROPFIND", true)) {
+                val properties = when (path) {
+                    PATH_CARDDAV + SUBPATH_PRINCIPAL ->
+                        "<resourcetype><principal/></resourcetype>" +
+                                "<displayname>Mr. Wobbles</displayname>" +
+                                "<CARD:addressbook-home-set>" +
+                                "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL}</href>" +
+                                "</CARD:addressbook-home-set>" +
+                                "<group-membership>" +
+                                "   <href>${PATH_CARDDAV}${SUBPATH_GROUPPRINCIPAL_0}</href>" +
+                                "</group-membership>"
+
+                    PATH_CARDDAV + SUBPATH_GROUPPRINCIPAL_0 ->
+                        "<resourcetype><principal/></resourcetype>" +
+                                "<displayname>All address books</displayname>" +
+                                "<CARD:addressbook-home-set>" +
+                                "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_PERSONAL}</href>" +
+                                "   <href>${PATH_CARDDAV}${SUBPATH_ADDRESSBOOK_HOMESET_NON_PERSONAL}</href>" +
+                                "</CARD:addressbook-home-set>"
+
+                    else -> ""
+                }
+                return MockResponse()
+                    .setResponseCode(207)
+                    .setBody(
+                        "<multistatus xmlns='DAV:' xmlns:CARD='urn:ietf:params:xml:ns:carddav' xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
+                                "<response>" +
+                                "   <href>$path</href>" +
+                                "   <propstat><prop>" +
+                                properties +
+                                "   </prop></propstat>" +
+                                "</response>" +
+                                "</multistatus>"
+                    )
+            }
+
+            return MockResponse().setResponseCode(404)
+        }
+
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/settings/migration/AccountSettingsMigration20Test.kt

@@ -127,16 +127,16 @@ class AccountSettingsMigration20Test {
                     Calendars.NAME to url,
                     Calendars.SYNC_EVENTS to 1
                 )
-            )!!
+            )!!.asSyncAdapter(account)
             try {
-                migration.migrateCalendars(account, calDavServiceId = 1)
+                migration.migrateCalendars(account, 1)
 
-                provider.query(uri.asSyncAdapter(account), arrayOf(Calendars._SYNC_ID), null, null, null)!!.use { cursor ->
+                provider.query(uri, arrayOf(Calendars._SYNC_ID), null, null, null)!!.use { cursor ->
                     cursor.moveToNext()
                     assertEquals(collectionId, cursor.getLongOrNull(0))
                 }
             } finally {
-                provider.delete(uri.asSyncAdapter(account), null, null)
+                provider.delete(uri, null, null)
             }
         }
     }

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/AndroidSyncFrameworkTest.kt

@@ -0,0 +1,230 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.sync
+
+import android.accounts.Account
+import android.content.ContentResolver
+import android.content.Context
+import android.content.SyncRequest
+import android.os.Bundle
+import android.provider.CalendarContract
+import androidx.test.filters.SdkSuppress
+import at.bitfire.davdroid.sync.account.TestAccount
+import dagger.hilt.android.qualifiers.ApplicationContext
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import io.mockk.junit4.MockKRule
+import junit.framework.AssertionFailedError
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.withTimeout
+import org.junit.After
+import org.junit.AfterClass
+import org.junit.Before
+import org.junit.BeforeClass
+import org.junit.Rule
+import org.junit.Test
+import java.util.Collections
+import java.util.LinkedList
+import java.util.logging.Logger
+import javax.inject.Inject
+import kotlin.time.Duration.Companion.seconds
+
+@HiltAndroidTest
+class AndroidSyncFrameworkTest {
+
+    @get:Rule
+    val hiltRule = HiltAndroidRule(this)
+
+    @get:Rule
+    val mockkRule = MockKRule(this)
+
+    @Inject
+    @ApplicationContext
+    lateinit var context: Context
+
+    @Inject
+    lateinit var logger: Logger
+
+    lateinit var account: Account
+    val authority = CalendarContract.AUTHORITY
+
+    private lateinit var stateChangeListener: Any
+    private val recordedStates = Collections.synchronizedList(LinkedList<State>())
+
+    @Before
+    fun setUp() {
+        hiltRule.inject()
+
+        account = TestAccount.create()
+
+        // Enable sync globally and for the test account
+        ContentResolver.setIsSyncable(account, authority, 1)
+
+        // Remember states the sync framework reports as pairs of (sync pending, sync active).
+        recordedStates.clear()
+        onStatusChanged(0)      // record first entry (pending = false, active = false)
+        stateChangeListener = ContentResolver.addStatusChangeListener(
+            ContentResolver.SYNC_OBSERVER_TYPE_PENDING or ContentResolver.SYNC_OBSERVER_TYPE_ACTIVE,
+            ::onStatusChanged
+        )
+    }
+
+    @After
+    fun tearDown() {
+        ContentResolver.removeStatusChangeListener(stateChangeListener)
+        TestAccount.remove(account)
+    }
+
+
+    /**
+     * Correct behaviour of the sync framework on Android 13 and below.
+     * Pending state is correctly reflected
+     */
+    @SdkSuppress(maxSdkVersion = 33)
+    @Test
+    fun testVerifySyncAlwaysPending_correctBehaviour_android13() {
+        verifySyncStates(
+            listOf(
+                State(pending = false, active = false),                 // no sync pending or active
+                State(pending = true, active = false, optional = true), // sync becomes pending
+                State(pending = true, active = true),                   // ... and pending and active at the same time
+                State(pending = false, active = true),                  // ... and then only active
+                State(pending = false, active = false)                  // sync finished
+            )
+        )
+    }
+
+    /**
+     * Wrong behaviour of the sync framework on Android 14+.
+     * Pending state stays true forever (after initial run), active state behaves correctly
+     */
+    @SdkSuppress(minSdkVersion = 34 /*, maxSdkVersion = 36 */)
+    @Test
+    fun testVerifySyncAlwaysPending_wrongBehaviour_android14() {
+        verifySyncStates(
+            listOf(
+                State(pending = false, active = false),                 // no sync pending or active
+                State(pending = true, active = false, optional = true), // sync becomes pending
+                State(pending = true, active = true),                   // ... and pending and active at the same time
+                State(pending = true, active = false)                   // ... and finishes, but stays pending
+            )
+        )
+    }
+
+
+    // helpers
+
+    private fun syncRequest() = SyncRequest.Builder()
+        .setSyncAdapter(account, authority)
+        .syncOnce()
+        .setExtras(Bundle())    // needed for Android 9
+        .setExpedited(true)     // sync request will be scheduled at the front of the sync request queue
+        .setManual(true)        // equivalent of setting both SYNC_EXTRAS_IGNORE_SETTINGS and SYNC_EXTRAS_IGNORE_BACKOFF
+        .build()
+
+    /**
+     * Verifies that the given expected states match the recorded states.
+     */
+    private fun verifySyncStates(expectedStates: List<State>) = runBlocking {
+        // We use runBlocking for these tests because it uses the default dispatcher
+        // which does not auto-advance virtual time and we need real system time to
+        // test the sync framework behavior.
+
+        ContentResolver.requestSync(syncRequest())
+
+        // Even though the always-pending-bug is present on Android 14+, the sync active
+        // state behaves correctly, so we can record the state changes as pairs (pending,
+        // active) and expect a certain sequence of state pairs to verify the presence or
+        // absence of the bug on different Android versions.
+        withTimeout(60.seconds) { // Usually takes less than 30 seconds
+            while (recordedStates.size < expectedStates.size) {
+                // verify already known states
+                if (recordedStates.isNotEmpty())
+                    assertStatesEqual(expectedStates.subList(0, recordedStates.size), recordedStates)
+
+                delay(500) // avoid busy-waiting
+            }
+
+            assertStatesEqual(expectedStates, recordedStates)
+        }
+    }
+
+    /**
+     * Asserts whether [actualStates] and [expectedStates] are the same, under the condition
+     * that expected states with the [State.optional] flag can be skipped.
+     */
+    private fun assertStatesEqual(expectedStates: List<State>, actualStates: List<State>) {
+        fun fail() {
+            throw AssertionFailedError("Expected states=$expectedStates, actual=$actualStates")
+        }
+
+        // iterate through entries
+        val expectedIterator = expectedStates.iterator()
+        for (actual in actualStates) {
+            if (!expectedIterator.hasNext())
+                fail()
+            var expected = expectedIterator.next()
+
+            // skip optional expected entries if they don't match the actual entry
+            while (!actual.stateEquals(expected) && expected.optional) {
+                if (!expectedIterator.hasNext())
+                    fail()
+                expected = expectedIterator.next()
+            }
+
+            if (!actual.stateEquals(expected))
+                fail()
+        }
+    }
+
+
+    // SyncStatusObserver implementation and data class
+
+    fun onStatusChanged(which: Int) {
+        val state = State(
+            pending = ContentResolver.isSyncPending(account, authority),
+            active = ContentResolver.isSyncActive(account, authority)
+        )
+        synchronized(recordedStates) {
+            if (recordedStates.lastOrNull() != state) {
+                logger.info("$account syncState = $state")
+                recordedStates += state
+            }
+        }
+    }
+
+    data class State(
+        val pending: Boolean,
+        val active: Boolean,
+        val optional: Boolean = false
+    ) {
+        fun stateEquals(other: State) =
+            pending == other.pending && active == other.active
+    }
+
+
+    companion object {
+
+        var globalAutoSyncBeforeTest = false
+
+        @BeforeClass
+        @JvmStatic
+        fun before() {
+            globalAutoSyncBeforeTest = ContentResolver.getMasterSyncAutomatically()
+
+            // We'll request syncs explicitly and with SYNC_EXTRAS_IGNORE_SETTINGS
+            ContentResolver.setMasterSyncAutomatically(false)
+        }
+
+        @AfterClass
+        @JvmStatic
+        fun after() {
+            ContentResolver.setMasterSyncAutomatically(globalAutoSyncBeforeTest)
+        }
+
+    }
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/FakeSyncAdapter.kt

@@ -0,0 +1,51 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.sync
+
+import android.accounts.Account
+import android.content.AbstractThreadedSyncAdapter
+import android.content.ContentProviderClient
+import android.content.Context
+import android.content.SyncResult
+import android.os.Bundle
+import android.os.IBinder
+import at.bitfire.davdroid.sync.adapter.SyncAdapter
+import dagger.hilt.android.qualifiers.ApplicationContext
+import java.util.logging.Level
+import java.util.logging.Logger
+import javax.inject.Inject
+
+class FakeSyncAdapter @Inject constructor(
+    @ApplicationContext context: Context,
+    private val logger: Logger
+): AbstractThreadedSyncAdapter(context, true), SyncAdapter {
+
+    init {
+        logger.info("FakeSyncAdapter created")
+    }
+
+    override fun onPerformSync(account: Account, extras: Bundle, authority: String, provider: ContentProviderClient, syncResult: SyncResult) {
+        logger.log(
+            Level.INFO,
+            "onPerformSync(account=$account, extras=$extras, authority=$authority, syncResult=$syncResult)",
+            extras.keySet().map { key -> "extras[$key] = ${extras[key]}" }
+        )
+
+        // fake 5 sec sync
+        try {
+            Thread.sleep(5000)
+        } catch (_: InterruptedException) {
+            logger.info("onPerformSync($account) cancelled")
+        }
+
+        logger.info("onPerformSync($account) finished")
+    }
+
+
+    // SyncAdapter implementation and Hilt module
+
+    override fun getBinder(): IBinder = syncAdapterBinder
+
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/JtxSyncManagerTest.kt

@@ -4,10 +4,9 @@
 
 package at.bitfire.davdroid.sync
 
+import android.accounts.Account
 import android.content.ContentProviderClient
 import android.content.Context
-import androidx.test.rule.GrantPermissionRule
-import at.bitfire.davdroid.CatchExceptionsRule
 import at.bitfire.davdroid.db.Collection
 import at.bitfire.davdroid.db.Service
 import at.bitfire.davdroid.network.HttpClient
@@ -18,6 +17,7 @@ import at.bitfire.davdroid.sync.account.TestAccount
 import at.bitfire.davdroid.util.PermissionUtils
 import at.bitfire.ical4android.TaskProvider
 import at.bitfire.ical4android.util.MiscUtils.closeCompat
+import at.bitfire.synctools.test.GrantPermissionOrSkipRule
 import at.techbee.jtx.JtxContract
 import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.android.testing.HiltAndroidRule
@@ -25,6 +25,7 @@ import dagger.hilt.android.testing.HiltAndroidTest
 import okhttp3.HttpUrl.Companion.toHttpUrl
 import org.junit.After
 import org.junit.Assert.assertEquals
+import org.junit.Assume.assumeNotNull
 import org.junit.Assume.assumeTrue
 import org.junit.Before
 import org.junit.Rule
@@ -60,12 +61,9 @@ class JtxSyncManagerTest {
     val hiltRule = HiltAndroidRule(this)
 
     @get:Rule
-    val permissionRule = CatchExceptionsRule(
-        GrantPermissionRule.grant(*TaskProvider.PERMISSIONS_JTX),
-        SecurityException::class
-    )
+    val permissionRule = GrantPermissionOrSkipRule(TaskProvider.PERMISSIONS_JTX.toSet())
 
-    private val account = TestAccount.create()
+    lateinit var account: Account
 
     private lateinit var provider: ContentProviderClient
     private lateinit var syncManager: JtxSyncManager
@@ -79,7 +77,11 @@ class JtxSyncManagerTest {
         assumeTrue(PermissionUtils.havePermissions(context, TaskProvider.PERMISSIONS_JTX))
 
         // Acquire the jtx content provider
-        provider = context.contentResolver.acquireContentProviderClient(JtxContract.AUTHORITY)!!
+        val providerOrNull = context.contentResolver.acquireContentProviderClient(JtxContract.AUTHORITY)
+        assumeNotNull(providerOrNull)
+        provider = providerOrNull!!
+
+        account = TestAccount.create()
 
         // Create dummy dependencies
         val service = Service(0, account.name, Service.TYPE_CALDAV, null)
@@ -106,9 +108,12 @@ class JtxSyncManagerTest {
         if (this::localJtxCollection.isInitialized)
             localJtxCollectionStore.delete(localJtxCollection)
         serviceRepository.deleteAllBlocking()
+
         if (this::provider.isInitialized)
             provider.closeCompat()
-        TestAccount.remove(account)
+
+        if (this::account.isInitialized)
+            TestAccount.remove(account)
     }
 
 

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/LocalTestCollection.kt

@@ -4,8 +4,8 @@
 
 package at.bitfire.davdroid.sync
 
-import at.bitfire.davdroid.db.SyncState
 import at.bitfire.davdroid.resource.LocalCollection
+import at.bitfire.davdroid.resource.SyncState
 
 class LocalTestCollection(
     override val dbCollectionId: Long = 0L

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/LocalTestResource.kt

@@ -5,6 +5,7 @@
 package at.bitfire.davdroid.sync
 
 import at.bitfire.davdroid.resource.LocalResource
+import java.util.Optional
 
 class LocalTestResource: LocalResource<Any> {
 
@@ -19,10 +20,10 @@ class LocalTestResource: LocalResource<Any> {
 
     override fun prepareForUpload() = "generated-file.txt"
 
-    override fun clearDirty(fileName: String?, eTag: String?, scheduleTag: String?) {
+    override fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String?) {
         dirty = false
-        if (fileName != null)
-            this.fileName = fileName
+        if (fileName.isPresent)
+            this.fileName = fileName.get()
         this.eTag = eTag
         this.scheduleTag = scheduleTag
     }
@@ -31,9 +32,8 @@ class LocalTestResource: LocalResource<Any> {
         this.flags = flags
     }
 
-    override fun add() = throw NotImplementedError()
-    override fun update(data: Any) = throw NotImplementedError()
-    override fun delete() = throw NotImplementedError()
+    override fun update(data: Any, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int) = throw NotImplementedError()
+    override fun deleteLocal() = throw NotImplementedError()
     override fun resetDeleted() = throw NotImplementedError()
 
 }

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/SyncAdapterImplTest.kt

@@ -5,6 +5,7 @@
 package at.bitfire.davdroid.sync
 
 import android.accounts.Account
+import android.content.ContentResolver
 import android.content.Context
 import android.content.SyncResult
 import android.os.Bundle
@@ -13,17 +14,17 @@ import androidx.hilt.work.HiltWorkerFactory
 import androidx.work.WorkInfo
 import androidx.work.WorkManager
 import at.bitfire.davdroid.TestUtils
-import at.bitfire.davdroid.repository.DavCollectionRepository
-import at.bitfire.davdroid.repository.DavServiceRepository
-import at.bitfire.davdroid.settings.AccountSettings
 import at.bitfire.davdroid.sync.account.TestAccount
+import at.bitfire.davdroid.sync.adapter.SyncAdapterImpl
 import at.bitfire.davdroid.sync.worker.SyncWorkerManager
 import dagger.hilt.android.qualifiers.ApplicationContext
+import dagger.hilt.android.testing.BindValue
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import io.mockk.Awaits
 import io.mockk.coEvery
 import io.mockk.every
+import io.mockk.impl.annotations.MockK
 import io.mockk.junit4.MockKRule
 import io.mockk.just
 import io.mockk.mockk
@@ -39,36 +40,12 @@ import org.junit.After
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
-import org.junit.rules.Timeout
-import java.util.logging.Logger
 import javax.inject.Inject
+import javax.inject.Provider
 import kotlin.coroutines.cancellation.CancellationException
 
 @HiltAndroidTest
-class SyncAdapterServicesTest {
-
-    lateinit var account: Account
-
-    @Inject
-    lateinit var accountSettingsFactory: AccountSettings.Factory
-
-    @Inject
-    lateinit var collectionRepository: DavCollectionRepository
-
-    @Inject @ApplicationContext
-    lateinit var context: Context
-
-    @Inject
-    lateinit var logger: Logger
-
-    @Inject
-    lateinit var serviceRepository: DavServiceRepository
-
-    @Inject
-    lateinit var syncConditionsFactory: SyncConditions.Factory
-
-    @Inject
-    lateinit var workerFactory: HiltWorkerFactory
+class SyncAdapterImplTest {
 
     @get:Rule
     val hiltRule = HiltAndroidRule(this)
@@ -76,10 +53,21 @@ class SyncAdapterServicesTest {
     @get:Rule
     val mockkRule = MockKRule(this)
 
-    // test methods should run quickly and not wait 60 seconds for a sync timeout or something like that
-    @get:Rule
-    val timeoutRule: Timeout = Timeout.seconds(5)
+    @Inject @ApplicationContext
+    lateinit var context: Context
 
+    @Inject
+    lateinit var syncAdapterImplProvider: Provider<SyncAdapterImpl>
+
+    @BindValue @MockK
+    lateinit var syncWorkerManager: SyncWorkerManager
+
+    @Inject
+    lateinit var workerFactory: HiltWorkerFactory
+
+    lateinit var account: Account
+
+    private var masterSyncStateBeforeTest = ContentResolver.getMasterSyncAutomatically()
 
     @Before
     fun setUp() {
@@ -87,33 +75,23 @@ class SyncAdapterServicesTest {
         TestUtils.setUpWorkManager(context, workerFactory)
 
         account = TestAccount.create()
+
+        ContentResolver.setMasterSyncAutomatically(true)
+        ContentResolver.setSyncAutomatically(account, CalendarContract.AUTHORITY, true)
+        ContentResolver.setIsSyncable(account, CalendarContract.AUTHORITY, 1)
     }
 
     @After
     fun tearDown() {
+        ContentResolver.setMasterSyncAutomatically(masterSyncStateBeforeTest)
         TestAccount.remove(account)
     }
 
 
-    private fun syncAdapter(
-        syncWorkerManager: SyncWorkerManager
-    ): SyncAdapterService.SyncAdapter =
-        SyncAdapterService.SyncAdapter(
-            accountSettingsFactory = accountSettingsFactory,
-            collectionRepository = collectionRepository,
-            serviceRepository = serviceRepository,
-            context = context,
-            logger = logger,
-            syncConditionsFactory = syncConditionsFactory,
-            syncWorkerManager = syncWorkerManager
-        )
-
-
     @Test
     fun testSyncAdapter_onPerformSync_cancellation() = runTest {
-        val syncWorkerManager = mockk<SyncWorkerManager>()
-        val syncAdapter = syncAdapter(syncWorkerManager = syncWorkerManager)
         val workManager = WorkManager.getInstance(context)
+        val syncAdapter = syncAdapterImplProvider.get()
 
         mockkObject(workManager) {
             // don't actually create a worker
@@ -136,9 +114,8 @@ class SyncAdapterServicesTest {
 
     @Test
     fun testSyncAdapter_onPerformSync_returnsAfterTimeout() {
-        val syncWorkerManager = mockk<SyncWorkerManager>()
-        val syncAdapter = syncAdapter(syncWorkerManager = syncWorkerManager)
         val workManager = WorkManager.getInstance(context)
+        val syncAdapter = syncAdapterImplProvider.get()
 
         mockkObject(workManager) {
             // don't actually create a worker
@@ -158,9 +135,8 @@ class SyncAdapterServicesTest {
 
     @Test
     fun testSyncAdapter_onPerformSync_runsInTime() {
-        val syncWorkerManager = mockk<SyncWorkerManager>()
-        val syncAdapter = syncAdapter(syncWorkerManager = syncWorkerManager)
         val workManager = WorkManager.getInstance(context)
+        val syncAdapter = syncAdapterImplProvider.get()
 
         mockkObject(workManager) {
             // don't actually create a worker
@@ -179,4 +155,4 @@ class SyncAdapterServicesTest {
         }
     }
 
-}
+}

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/SyncManagerTest.kt

@@ -15,9 +15,9 @@ import at.bitfire.dav4jvm.property.webdav.GetETag
 import at.bitfire.davdroid.TestUtils
 import at.bitfire.davdroid.TestUtils.assertWithin
 import at.bitfire.davdroid.db.Collection
-import at.bitfire.davdroid.db.SyncState
 import at.bitfire.davdroid.network.HttpClient
 import at.bitfire.davdroid.repository.DavSyncStatsRepository
+import at.bitfire.davdroid.resource.SyncState
 import at.bitfire.davdroid.settings.AccountSettings
 import at.bitfire.davdroid.sync.account.TestAccount
 import dagger.hilt.android.qualifiers.ApplicationContext

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/SyncerTest.kt

@@ -189,7 +189,7 @@ class SyncerTest {
         override val authority: String
             get() = throw NotImplementedError()
 
-        override fun acquireContentProvider(): ContentProviderClient? {
+        override fun acquireContentProvider(throwOnMissingPermissions: Boolean): ContentProviderClient? {
             throw NotImplementedError()
         }
 

app/src/androidTest/kotlin/at/bitfire/davdroid/sync/TestSyncManager.kt

@@ -10,10 +10,10 @@ import at.bitfire.dav4jvm.MultiResponseCallback
 import at.bitfire.dav4jvm.Response
 import at.bitfire.dav4jvm.property.caldav.GetCTag
 import at.bitfire.davdroid.db.Collection
-import at.bitfire.davdroid.db.SyncState
 import at.bitfire.davdroid.di.SyncDispatcher
 import at.bitfire.davdroid.network.HttpClient
 import at.bitfire.davdroid.resource.LocalResource
+import at.bitfire.davdroid.resource.SyncState
 import at.bitfire.davdroid.util.DavUtils.lastSegment
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory

app/src/androidTest/kotlin/at/bitfire/davdroid/webdav/CredentialsStoreTest.kt

@@ -4,7 +4,7 @@
 
 package at.bitfire.davdroid.webdav
 
-import at.bitfire.davdroid.db.Credentials
+import at.bitfire.davdroid.settings.Credentials
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import org.junit.Assert.assertEquals

app/src/androidTest/kotlin/at/bitfire/davdroid/webdav/WebDavMountRepositoryTest.kt

@@ -6,11 +6,11 @@ package at.bitfire.davdroid.webdav
 
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
+import junit.framework.TestCase.assertEquals
 import kotlinx.coroutines.test.runTest
 import okhttp3.mockwebserver.MockResponse
 import okhttp3.mockwebserver.MockWebServer
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertTrue
+import org.junit.Assert.assertNull
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
@@ -36,7 +36,7 @@ class WebDavMountRepositoryTest {
     @Test
     fun testHasWebDav_NoDavHeader() = runTest {
         web.enqueue(MockResponse().setResponseCode(200))
-        assertFalse(repository.hasWebDav(url, null))
+        assertNull(repository.hasWebDav(url, null))
     }
 
     @Test
@@ -44,7 +44,7 @@ class WebDavMountRepositoryTest {
         web.enqueue(MockResponse()
             .setResponseCode(200)
             .addHeader("DAV: 1"))
-        assertTrue(repository.hasWebDav(url, null))
+        assertEquals(url, repository.hasWebDav(url, null))
     }
 
     @Test
@@ -52,7 +52,7 @@ class WebDavMountRepositoryTest {
         web.enqueue(MockResponse()
             .setResponseCode(200)
             .addHeader("DAV: 1, 2"))
-        assertTrue(repository.hasWebDav(url, null))
+        assertEquals(url,repository.hasWebDav(url, null))
     }
 
     @Test
@@ -60,7 +60,7 @@ class WebDavMountRepositoryTest {
         web.enqueue(MockResponse()
             .setResponseCode(200)
             .addHeader("DAV: 1, 3"))
-        assertTrue(repository.hasWebDav(url, null))
+        assertEquals(url,repository.hasWebDav(url, null))
     }
 
 }

app/src/androidTest/kotlin/at/bitfire/davdroid/webdav/operation/QueryChildDocumentsOperationTest.kt

@@ -2,7 +2,7 @@
  * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
  */
 
-package at.bitfire.davdroid.webdav
+package at.bitfire.davdroid.webdav.operation
 
 import android.content.Context
 import android.security.NetworkSecurityPolicy
@@ -14,8 +14,8 @@ import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.android.testing.HiltAndroidRule
 import dagger.hilt.android.testing.HiltAndroidTest
 import io.mockk.junit4.MockKRule
+import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.test.runTest
-import okhttp3.CookieJar
 import okhttp3.mockwebserver.Dispatcher
 import okhttp3.mockwebserver.MockResponse
 import okhttp3.mockwebserver.MockWebServer
@@ -30,29 +30,7 @@ import java.util.logging.Logger
 import javax.inject.Inject
 
 @HiltAndroidTest
-class DavDocumentsProviderTest {
-
-    companion object {
-        private const val PATH_WEBDAV_ROOT = "/webdav"
-    }
-
-    @Inject @ApplicationContext
-    lateinit var context: Context
-
-    @Inject
-    lateinit var credentialsStore: CredentialsStore
-    
-    @Inject
-    lateinit var davDocumentsActorFactory: DavDocumentsProvider.DavDocumentsActor.Factory
-
-    @Inject
-    lateinit var httpClientBuilder: HttpClient.Builder
-    
-    @Inject
-    lateinit var db: AppDatabase
-
-    @Inject
-    lateinit var testDispatcher: TestDispatcher
+class QueryChildDocumentsOperationTest {
 
     @get:Rule
     val hiltRule = HiltAndroidRule(this)
@@ -60,13 +38,32 @@ class DavDocumentsProviderTest {
     @get:Rule
     val mockkRule = MockKRule(this)
 
+    @Inject @ApplicationContext
+    lateinit var context: Context
+
+    @Inject
+    lateinit var db: AppDatabase
+
+    @Inject
+    lateinit var operation: QueryChildDocumentsOperation
+
+    @Inject
+    lateinit var httpClientBuilder: HttpClient.Builder
+
+    @Inject
+    lateinit var testDispatcher: TestDispatcher
+
     private lateinit var server: MockWebServer
     private lateinit var client: HttpClient
 
+    private lateinit var mount: WebDavMount
+    private lateinit var rootDocument: WebDavDocument
+
     @Before
     fun setUp() {
         hiltRule.inject()
 
+        // create server and client
         server = MockWebServer().apply {
             dispatcher = testDispatcher
             start()
@@ -76,50 +73,49 @@ class DavDocumentsProviderTest {
 
         // mock server delivers HTTP without encryption
         assertTrue(NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted)
+
+        // create WebDAV mount and root document in DB
+        runBlocking {
+            val mountId = db.webDavMountDao().insert(WebDavMount(0, "Cat food storage", server.url(PATH_WEBDAV_ROOT)))
+            mount = db.webDavMountDao().getById(mountId)
+            rootDocument = db.webDavDocumentDao().getOrCreateRoot(mount)
+        }
     }
 
     @After
     fun tearDown() {
         client.close()
         server.shutdown()
+
+        runBlocking {
+            db.webDavMountDao().deleteAsync(mount)
+        }
     }
 
 
     @Test
     fun testDoQueryChildren_insert() = runTest {
-        // Create parent and root in database
-        val id = db.webDavMountDao().insert(WebDavMount(0, "Cat food storage", server.url(PATH_WEBDAV_ROOT)))
-        val webDavMount = db.webDavMountDao().getById(id)
-        val parent = db.webDavDocumentDao().getOrCreateRoot(webDavMount)
-
         // Query
-        val actor = davDocumentsActorFactory.create(
-            cookieStore = mutableMapOf<Long, CookieJar>(),
-            credentialsStore = credentialsStore
-        )
-        actor.queryChildren(parent)
+        operation.queryChildren(rootDocument)
 
         // Assert new children were inserted into db
-        assertEquals(3, db.webDavDocumentDao().getChildren(parent.id).size)
-        assertEquals("Library", db.webDavDocumentDao().getChildren(parent.id)[0].displayName)
-        assertEquals("MeowMeow_Cats.docx", db.webDavDocumentDao().getChildren(parent.id)[1].displayName)
-        assertEquals("Secret_Document.pages", db.webDavDocumentDao().getChildren(parent.id)[2].displayName)
+        assertEquals(3, db.webDavDocumentDao().getChildren(rootDocument.id).size)
+        assertEquals("Library", db.webDavDocumentDao().getChildren(rootDocument.id)[0].displayName)
+        assertEquals("MeowMeow_Cats.docx", db.webDavDocumentDao().getChildren(rootDocument.id)[1].displayName)
+        assertEquals("Secret_Document.pages", db.webDavDocumentDao().getChildren(rootDocument.id)[2].displayName)
     }
 
     @Test
     fun testDoQueryChildren_update() = runTest {
         // Create parent and root in database
-        val mountId = db.webDavMountDao().insert(WebDavMount(0, "Cat food storage", server.url(PATH_WEBDAV_ROOT)))
-        val webDavMount = db.webDavMountDao().getById(mountId)
-        val parent = db.webDavDocumentDao().getOrCreateRoot(webDavMount)
-        assertEquals("Cat food storage", db.webDavDocumentDao().get(parent.id)!!.displayName)
+        assertEquals("Cat food storage", db.webDavDocumentDao().get(rootDocument.id)!!.displayName)
 
         // Create a folder
         val folderId = db.webDavDocumentDao().insert(
             WebDavDocument(
                 0,
-                mountId,
-                parent.id,
+                mount.id,
+                rootDocument.id,
                 "My_Books",
                 true,
                 "My Books",
@@ -129,38 +125,25 @@ class DavDocumentsProviderTest {
         assertEquals("My Books", db.webDavDocumentDao().get(folderId)!!.displayName)
 
         // Query - should update the parent displayname and folder name
-        val actor = davDocumentsActorFactory.create(
-            cookieStore = mutableMapOf<Long, CookieJar>(),
-            credentialsStore = credentialsStore
-        )
-        actor.queryChildren(parent)
+        operation.queryChildren(rootDocument)
 
         // Assert parent and children were updated in database
-        assertEquals("Cats WebDAV", db.webDavDocumentDao().get(parent.id)!!.displayName)
-        assertEquals("Library", db.webDavDocumentDao().getChildren(parent.id)[0].name)
-        assertEquals("Library", db.webDavDocumentDao().getChildren(parent.id)[0].displayName)
+        assertEquals("Cats WebDAV", db.webDavDocumentDao().get(rootDocument.id)!!.displayName)
+        assertEquals("Library", db.webDavDocumentDao().getChildren(rootDocument.id)[0].name)
+        assertEquals("Library", db.webDavDocumentDao().getChildren(rootDocument.id)[0].displayName)
 
     }
 
     @Test
     fun testDoQueryChildren_delete() = runTest {
-        // Create parent and root in database
-        val mountId = db.webDavMountDao().insert(WebDavMount(0, "Cat food storage", server.url(PATH_WEBDAV_ROOT)))
-        val webDavMount = db.webDavMountDao().getById(mountId)
-        val parent = db.webDavDocumentDao().getOrCreateRoot(webDavMount)
-
         // Create a folder
         val folderId = db.webDavDocumentDao().insert(
-            WebDavDocument(0, mountId, parent.id, "deleteme", true, "Should be deleted")
+            WebDavDocument(0, mount.id, rootDocument.id, "deleteme", true, "Should be deleted")
         )
         assertEquals("deleteme", db.webDavDocumentDao().get(folderId)!!.name)
 
         // Query - discovers serverside deletion
-        val actor = davDocumentsActorFactory.create(
-            cookieStore = mutableMapOf<Long, CookieJar>(),
-            credentialsStore = credentialsStore
-        )
-        actor.queryChildren(parent)
+        operation.queryChildren(rootDocument)
 
         // Assert folder got deleted
         assertEquals(null, db.webDavDocumentDao().get(folderId))
@@ -168,26 +151,17 @@ class DavDocumentsProviderTest {
 
     @Test
     fun testDoQueryChildren_updateTwoDirectoriesSimultaneously() = runTest {
-        // Create root in database
-        val mountId = db.webDavMountDao().insert(WebDavMount(0, "Cat food storage", server.url(PATH_WEBDAV_ROOT)))
-        val webDavMount = db.webDavMountDao().getById(mountId)
-        val root = db.webDavDocumentDao().getOrCreateRoot(webDavMount)
-
         // Create two directories
-        val parent1Id = db.webDavDocumentDao().insert(WebDavDocument(0, mountId, root.id, "parent1", true))
-        val parent2Id = db.webDavDocumentDao().insert(WebDavDocument(0, mountId, root.id, "parent2", true))
+        val parent1Id = db.webDavDocumentDao().insert(WebDavDocument(0, mount.id, rootDocument.id, "parent1", true))
+        val parent2Id = db.webDavDocumentDao().insert(WebDavDocument(0, mount.id, rootDocument.id, "parent2", true))
         val parent1 = db.webDavDocumentDao().get(parent1Id)!!
         val parent2 = db.webDavDocumentDao().get(parent2Id)!!
         assertEquals("parent1", parent1.name)
         assertEquals("parent2", parent2.name)
 
         // Query - find children of two nodes simultaneously
-        val actor = davDocumentsActorFactory.create(
-            cookieStore = mutableMapOf<Long, CookieJar>(),
-            credentialsStore = credentialsStore
-        )
-        actor.queryChildren(parent1)
-        actor.queryChildren(parent2)
+        operation.queryChildren(parent1)
+        operation.queryChildren(parent2)
 
         // Assert the two folders names have changed
         assertEquals("childOne.txt", db.webDavDocumentDao().getChildren(parent1Id)[0].name)
@@ -215,7 +189,7 @@ class DavDocumentsProviderTest {
                     PATH_WEBDAV_ROOT to arrayOf(
                         Resource("",
                             "<resourcetype><collection/></resourcetype>" +
-                            "<displayname>Cats WebDAV</displayname>"
+                                    "<displayname>Cats WebDAV</displayname>"
                         ),
                         Resource("Secret_Document.pages",
                             "<displayname>Secret_Document.pages</displayname>",
@@ -225,7 +199,7 @@ class DavDocumentsProviderTest {
                         ),
                         Resource("Library",
                             "<resourcetype><collection/></resourcetype>" +
-                            "<displayname>Library</displayname>"
+                                    "<displayname>Library</displayname>"
                         )
                     ),
 
@@ -244,15 +218,15 @@ class DavDocumentsProviderTest {
                 val responses = propsMap[requestPath]?.joinToString { resource ->
                     "<response><href>$requestPath/${resource.name}</href><propstat><prop>" +
                             resource.props +
-                    "</prop></propstat></response>"
+                            "</prop></propstat></response>"
                 }
 
                 val multistatus =
                     "<multistatus xmlns='DAV:' " +
-                        "xmlns:CARD='urn:ietf:params:xml:ns:carddav' " +
-                        "xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
-                        responses +
-                    "</multistatus>"
+                            "xmlns:CARD='urn:ietf:params:xml:ns:carddav' " +
+                            "xmlns:CAL='urn:ietf:params:xml:ns:caldav'>" +
+                            responses +
+                            "</multistatus>"
 
                 logger.info("Response: $multistatus")
                 return MockResponse()
@@ -265,4 +239,9 @@ class DavDocumentsProviderTest {
 
     }
 
+
+    companion object {
+        private const val PATH_WEBDAV_ROOT = "/webdav"
+    }
+
 }

app/src/main/AndroidManifest.xml

@@ -53,11 +53,19 @@
         tools:ignore="UnusedAttribute"
         android:supportsRtl="true">
 
-        <!-- required for Hilt/WorkManager integration -->
+        <!-- Required for Hilt/WorkManager integration. See
+        - https://developer.android.com/develop/background-work/background-tasks/persistent/configuration/custom-configuration#remove-default
+        - https://developer.android.com/training/dependency-injection/hilt-jetpack#workmanager
+        However, we must not disable AndroidX startup completely, as it's needed by other libraries like okhttp. -->
         <provider
             android:name="androidx.startup.InitializationProvider"
             android:authorities="${applicationId}.androidx-startup"
-            tools:node="remove">
+            android:exported="false"
+            tools:node="merge">
+            <meta-data
+                android:name="androidx.work.WorkManagerInitializer"
+                android:value="androidx.startup"
+                tools:node="remove" />
         </provider>
 
         <!-- Remove the node added by AppAuth (remove only from net.openid.appauth library, not from our flavor manifest files) -->
@@ -178,7 +186,7 @@
                 android:resource="@xml/account_authenticator"/>
         </service>
         <service
-            android:name=".sync.CalendarsSyncAdapterService"
+            android:name=".sync.adapter.CalendarsSyncAdapterService"
             android:exported="true"
             tools:ignore="ExportedService">
             <intent-filter>
@@ -189,7 +197,7 @@
                 android:resource="@xml/sync_calendars"/>
         </service>
         <service
-            android:name=".sync.JtxSyncAdapterService"
+            android:name=".sync.adapter.JtxSyncAdapterService"
             android:exported="true"
             tools:ignore="ExportedService">
             <intent-filter>
@@ -200,7 +208,7 @@
                 android:resource="@xml/sync_notes"/>
         </service>
         <service
-            android:name=".sync.OpenTasksSyncAdapterService"
+            android:name=".sync.adapter.OpenTasksSyncAdapterService"
             android:exported="true"
             tools:ignore="ExportedService">
             <intent-filter>
@@ -211,7 +219,7 @@
                 android:resource="@xml/sync_opentasks"/>
         </service>
         <service
-            android:name=".sync.TasksOrgSyncAdapterService"
+            android:name=".sync.adapter.TasksOrgSyncAdapterService"
             android:exported="true"
             tools:ignore="ExportedService">
             <intent-filter>
@@ -246,7 +254,7 @@
                 android:resource="@xml/account_authenticator_address_book"/>
         </service>
         <service
-            android:name=".sync.ContactsSyncAdapterService"
+            android:name=".sync.adapter.ContactsSyncAdapterService"
             android:exported="true"
             tools:ignore="ExportedService">
             <intent-filter>

app/src/main/kotlin/at/bitfire/davdroid/Constants.kt

@@ -3,8 +3,9 @@
  */
 package at.bitfire.davdroid
 
-import android.net.Uri
-import androidx.core.net.toUri
+import at.bitfire.synctools.icalendar.ical4jVersion
+import ezvcard.Ezvcard
+import net.fortuna.ical4j.model.property.ProdId
 
 /**
  * Brand-specific constants like (non-theme) colors, homepage URLs etc.
@@ -13,48 +14,10 @@ object Constants {
 
     const val DAVDROID_GREEN_RGBA = 0xFF8bc34a.toInt()
 
-    val HOMEPAGE_URL = "https://www.davx5.com".toUri()
-    const val HOMEPAGE_PATH_FAQ = "faq"
-    const val HOMEPAGE_PATH_FAQ_SYNC_NOT_RUN = "synchronization-is-not-run-as-expected"
-    const val HOMEPAGE_PATH_FAQ_LOCATION_PERMISSION = "wifi-ssid-restriction-location-permission"
-    const val HOMEPAGE_PATH_OPEN_SOURCE = "donate"
-    const val HOMEPAGE_PATH_PRIVACY = "privacy"
-    const val HOMEPAGE_PATH_TESTED_SERVICES = "tested-with"
 
-    val MANUAL_URL = "https://manual.davx5.com".toUri()
+    // product IDs for iCalendar/vCard
 
-    const val MANUAL_PATH_ACCOUNTS_COLLECTIONS = "accounts_collections.html"
-    const val MANUAL_FRAGMENT_SERVICE_DISCOVERY = "how-does-service-discovery-work"
-
-    const val MANUAL_PATH_INTRODUCTION = "introduction.html"
-    const val MANUAL_FRAGMENT_AUTHENTICATION_METHODS = "authentication-methods"
-
-    const val MANUAL_PATH_SETTINGS = "settings.html"
-    const val MANUAL_FRAGMENT_APP_SETTINGS = "app-wide-settings"
-    const val MANUAL_FRAGMENT_ACCOUNT_SETTINGS = "account-settings"
-
-    const val MANUAL_PATH_WEBDAV_PUSH = "webdav_push.html"
-    const val MANUAL_PATH_WEBDAV_MOUNTS = "webdav_mounts.html"
-
-    val COMMUNITY_URL = "https://github.com/bitfireAT/davx5-ose/discussions".toUri()
-
-    val FEDIVERSE_HANDLE = "@davx5app@fosstodon.org"
-    val FEDIVERSE_URL = "https://fosstodon.org/@davx5app".toUri()
-
-    /**
-     * Appends query parameters for anonymized usage statistics (app ID, version).
-     * Can be used by the called Website to get an idea of which versions etc. are currently used.
-     *
-     * @param context   optional info about from where the URL was opened (like a specific Activity)
-     */
-    fun Uri.Builder.withStatParams(context: String? = null): Uri.Builder {
-        appendQueryParameter("pk_campaign", BuildConfig.APPLICATION_ID)
-        appendQueryParameter("app-version", BuildConfig.VERSION_NAME)
-
-        if (context != null)
-            appendQueryParameter("pk_kwd", context)
-
-        return this
-    }
+    val iCalProdId = ProdId("DAVx5/${BuildConfig.VERSION_NAME} ical4j/$ical4jVersion")
+    const val vCardProdId = "+//IDN bitfire.at//DAVx5/${BuildConfig.VERSION_NAME} ez-vcard/${Ezvcard.VERSION}"
 
 }

app/src/main/kotlin/at/bitfire/davdroid/db/AppDatabase.kt

@@ -35,6 +35,13 @@ import dagger.hilt.components.SingletonComponent
 import java.io.Writer
 import javax.inject.Singleton
 
+/**
+ * The app database. Managed via android jetpack room. Room provides an abstraction
+ * layer over SQLite.
+ *
+ * Note: In SQLite PRAGMA foreign_keys is off by default. Room activates it for
+ * production (non-test) databases.
+ */
 @Database(entities = [
     Service::class,
     HomeSet::class,

app/src/main/kotlin/at/bitfire/davdroid/db/CollectionDao.kt

@@ -38,6 +38,10 @@ interface CollectionDao {
     @Query("SELECT * FROM collection WHERE pushTopic=:topic AND sync")
     suspend fun getSyncableByPushTopic(topic: String): Collection?
 
+    @Suppress("unused")     // for build variant
+    @Query("SELECT * FROM collection WHERE sync")
+    fun getSyncCollections(): List<Collection>
+
     @Query("SELECT pushVapidKey FROM collection WHERE serviceId=:serviceId AND pushVapidKey IS NOT NULL LIMIT 1")
     suspend fun getFirstVapidKey(serviceId: Long): String?
 

app/src/main/kotlin/at/bitfire/davdroid/db/Converters.kt

@@ -14,7 +14,7 @@ class Converters {
 
     @TypeConverter
     fun httpUrlToString(url: HttpUrl?) =
-            url?.toString()
+        url?.toString()
 
     @TypeConverter
     fun mediaTypeToString(mediaType: MediaType?) =

app/src/main/kotlin/at/bitfire/davdroid/db/HomeSetDao.kt

@@ -8,6 +8,7 @@ import androidx.room.Dao
 import androidx.room.Delete
 import androidx.room.Insert
 import androidx.room.Query
+import androidx.room.Transaction
 import androidx.room.Update
 import kotlinx.coroutines.flow.Flow
 
@@ -35,6 +36,24 @@ interface HomeSetDao {
     @Update
     fun update(homeset: HomeSet)
 
+    /**
+     * If a homeset with the given service ID and URL already exists, it is updated with the other fields.
+     * Otherwise, a new homeset is inserted.
+     *
+     * This method preserves the primary key, as opposed to using "@Insert(onConflict = OnConflictStrategy.REPLACE)"
+     * which will create a new row with incremented ID and thus breaks entity relationships!
+     *
+     * @param homeSet   home set to insert/update
+     *
+     * @return ID of the row that has been inserted or updated. -1 If the insert fails due to other reasons.
+     */
+    @Transaction
+    fun insertOrUpdateByUrlBlocking(homeSet: HomeSet): Long =
+        getByUrl(homeSet.serviceId, homeSet.url.toString())?.let { existingHomeset ->
+            update(homeSet.copy(id = existingHomeset.id))
+            existingHomeset.id
+        } ?: insert(homeSet)
+
     @Delete
     fun delete(homeset: HomeSet)
 

app/src/main/kotlin/at/bitfire/davdroid/log/LogFileHandler.kt

@@ -12,9 +12,11 @@ import androidx.core.app.NotificationCompat
 import androidx.core.app.NotificationManagerCompat
 import androidx.core.app.TaskStackBuilder
 import at.bitfire.davdroid.R
+import at.bitfire.davdroid.log.LogFileHandler.Companion.debugDir
 import at.bitfire.davdroid.ui.AppSettingsActivity
 import at.bitfire.davdroid.ui.DebugInfoActivity
 import at.bitfire.davdroid.ui.NotificationRegistry
+import at.bitfire.synctools.log.PlainTextFormatter
 import dagger.hilt.android.qualifiers.ApplicationContext
 import java.io.Closeable
 import java.io.File

app/src/main/kotlin/at/bitfire/davdroid/log/LogManager.kt

@@ -8,6 +8,7 @@ import android.content.Context
 import android.util.Log
 import at.bitfire.davdroid.BuildConfig
 import at.bitfire.davdroid.repository.PreferenceRepository
+import at.bitfire.synctools.log.LogcatHandler
 import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -79,7 +80,7 @@ class LogManager @Inject constructor(
         // root logger: set default log level and always log to logcat
         val rootLogger = Logger.getLogger("")
         rootLogger.level = if (logVerbose) Level.ALL else Level.INFO
-        rootLogger.addHandler(LogcatHandler())
+        rootLogger.addHandler(LogcatHandler(BuildConfig.APPLICATION_ID))
 
         // log to file, if requested
         if (logToFile)

app/src/main/kotlin/at/bitfire/davdroid/log/LogcatHandler.kt

@@ -1,52 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.log
-
-import android.os.Build
-import android.util.Log
-import at.bitfire.davdroid.BuildConfig
-import com.google.common.base.Ascii
-import java.util.logging.Handler
-import java.util.logging.Level
-import java.util.logging.LogRecord
-
-/**
- * Logging handler that logs to Android logcat.
- */
-internal class LogcatHandler: Handler() {
-
-    init {
-        formatter = PlainTextFormatter.LOGCAT
-    }
-
-    override fun publish(r: LogRecord) {
-        val level = r.level.intValue()
-        val text = formatter.format(r)
-
-        // get class name that calls the logger (or fall back to package name)
-        val className = if (r.sourceClassName != null)
-            PlainTextFormatter.shortClassName(r.sourceClassName)
-        else
-            BuildConfig.APPLICATION_ID
-
-        // truncate class name to 23 characters on Android <8, see Log documentation
-        val tag = if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O)
-            Ascii.truncate(className, 23, "")
-        else
-            className
-
-        when {
-            level >= Level.SEVERE.intValue()  -> Log.e(tag, text, r.thrown)
-            level >= Level.WARNING.intValue() -> Log.w(tag, text, r.thrown)
-            level >= Level.CONFIG.intValue()  -> Log.i(tag, text, r.thrown)
-            level >= Level.FINER.intValue()   -> Log.d(tag, text, r.thrown)
-            else                              -> Log.v(tag, text, r.thrown)
-        }
-    }
-
-    override fun flush() {}
-    override fun close() {}
-
-}

app/src/main/kotlin/at/bitfire/davdroid/log/PlainTextFormatter.kt

@@ -1,111 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.log
-
-import com.google.common.base.Ascii
-import java.io.PrintWriter
-import java.io.StringWriter
-import java.text.SimpleDateFormat
-import java.util.Date
-import java.util.Locale
-import java.util.logging.Formatter
-import java.util.logging.LogRecord
-
-class PlainTextFormatter(
-    private val withTime: Boolean,
-    private val withSource: Boolean,
-    private val padSource: Int = 30,
-    private val withException: Boolean,
-    private val lineSeparator: String?
-): Formatter() {
-
-    companion object {
-
-        /**
-         * Formatter intended for logcat output.
-         */
-        val LOGCAT = PlainTextFormatter(
-            withTime = false,
-            withSource = false,
-            withException = false,
-            lineSeparator = null
-        )
-
-        /**
-         * Formatter intended for file output.
-         */
-        val DEFAULT = PlainTextFormatter(
-            withTime = true,
-            withSource = true,
-            withException = true,
-            lineSeparator = System.lineSeparator()
-        )
-
-        /**
-         * Maximum length of a log line (estimate).
-         */
-        const val MAX_LENGTH = 10000
-
-        fun shortClassName(className: String) = className
-            .replace(Regex("^at\\.bitfire\\.(dav|cert4an|dav4an|ical4an|vcard4an)droid\\."), ".")
-            .replace(Regex("\\$.*$"), "")
-
-        private fun stackTrace(ex: Throwable): String {
-            val writer = StringWriter()
-            ex.printStackTrace(PrintWriter(writer))
-            return writer.toString()
-        }
-
-    }
-
-    private val timeFormat = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ROOT)
-
-
-    override fun format(r: LogRecord): String {
-        val builder = StringBuilder()
-
-        if (withTime)
-            builder .append(timeFormat.format(Date(r.millis)))
-                    .append(" ").append(r.threadID).append(" ")
-
-        if (withSource && r.sourceClassName != null) {
-            val className = shortClassName(r.sourceClassName)
-            if (className != r.loggerName) {
-                val classNameColumn = "[$className] ".padEnd(padSource)
-                builder.append(classNameColumn)
-            }
-        }
-
-        builder.append(truncate(r.message))
-
-        if (withException && r.thrown != null) {
-            val indentedStackTrace = stackTrace(r.thrown)
-                .replace("\n", "\n\t")
-                .removeSuffix("\t")
-            builder.append("\n\tEXCEPTION ").append(indentedStackTrace)
-        }
-
-        r.parameters?.let {
-            for ((idx, param) in it.withIndex()) {
-                builder.append("\n\tPARAMETER #").append(idx + 1).append(" = ")
-
-                val valStr = if (param == null)
-                    "(null)"
-                else
-                    truncate(param.toString())
-                builder.append(valStr)
-            }
-        }
-
-        if (lineSeparator != null)
-            builder.append(lineSeparator)
-
-        return builder.toString()
-    }
-
-    private fun truncate(s: String) =
-        Ascii.truncate(s, MAX_LENGTH, "[…]")
-
-}

app/src/main/kotlin/at/bitfire/davdroid/log/StringHandler.kt

@@ -4,6 +4,7 @@
 
 package at.bitfire.davdroid.log
 
+import at.bitfire.synctools.log.PlainTextFormatter
 import com.google.common.base.Ascii
 import java.util.logging.Handler
 import java.util.logging.LogRecord

app/src/main/kotlin/at/bitfire/davdroid/network/BearerAuthInterceptor.kt

@@ -1,72 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.network
-
-import kotlinx.coroutines.CancellationException
-import kotlinx.coroutines.CompletableDeferred
-import kotlinx.coroutines.runBlocking
-import net.openid.appauth.AuthState
-import net.openid.appauth.AuthorizationException
-import net.openid.appauth.AuthorizationService
-import okhttp3.Interceptor
-import okhttp3.Response
-import java.util.logging.Level
-import java.util.logging.Logger
-
-/**
- * Sends an OAuth Bearer token authorization as described in RFC 6750.
- */
-class BearerAuthInterceptor(
-    private val accessToken: String
-): Interceptor {
-
-    companion object {
-
-        val logger: Logger
-            get() = Logger.getGlobal()
-
-        fun fromAuthState(authService: AuthorizationService, authState: AuthState, callback: AuthStateUpdateCallback? = null): BearerAuthInterceptor? {
-            return runBlocking {
-                val accessTokenFuture = CompletableDeferred<String>()
-
-                authState.performActionWithFreshTokens(authService) { accessToken: String?, _: String?, ex: AuthorizationException? ->
-                    if (accessToken != null) {
-                        // persist updated AuthState
-                        callback?.onUpdate(authState)
-
-                        // emit access token
-                        accessTokenFuture.complete(accessToken)
-                    }
-                    else {
-                        logger.log(Level.WARNING, "Couldn't obtain access token", ex)
-                        accessTokenFuture.cancel()
-                    }
-                }
-
-                // return value
-                try {
-                    BearerAuthInterceptor(accessTokenFuture.await())
-                } catch (ignored: CancellationException) {
-                    null
-                }
-            }
-        }
-
-    }
-
-    override fun intercept(chain: Interceptor.Chain): Response {
-        logger.finer("Authenticating request with access token")
-        val rq = chain.request().newBuilder()
-            .header("Authorization", "Bearer $accessToken")
-            .build()
-        return chain.proceed(rq)
-    }
-
-
-    fun interface AuthStateUpdateCallback {
-        fun onUpdate(authState: AuthState)
-    }
-
-}

app/src/main/kotlin/at/bitfire/davdroid/network/HttpClient.kt

@@ -10,9 +10,10 @@ import androidx.annotation.WorkerThread
 import at.bitfire.cert4android.CustomCertManager
 import at.bitfire.dav4jvm.BasicDigestAuthHandler
 import at.bitfire.dav4jvm.UrlUtils
-import at.bitfire.davdroid.db.Credentials
+import at.bitfire.davdroid.BuildConfig
 import at.bitfire.davdroid.di.IoDispatcher
 import at.bitfire.davdroid.settings.AccountSettings
+import at.bitfire.davdroid.settings.Credentials
 import at.bitfire.davdroid.settings.Settings
 import at.bitfire.davdroid.settings.SettingsManager
 import at.bitfire.davdroid.ui.ForegroundTracker
@@ -21,7 +22,6 @@ import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.withContext
 import net.openid.appauth.AuthState
-import net.openid.appauth.AuthorizationService
 import okhttp3.Authenticator
 import okhttp3.Cache
 import okhttp3.ConnectionSpec
@@ -39,17 +39,14 @@ import java.util.concurrent.TimeUnit
 import java.util.logging.Level
 import java.util.logging.Logger
 import javax.inject.Inject
-import javax.inject.Provider
 import javax.net.ssl.KeyManager
 import javax.net.ssl.SSLContext
 
 class HttpClient(
-    val okHttpClient: OkHttpClient,
-    private val authorizationService: AuthorizationService? = null
+    val okHttpClient: OkHttpClient
 ): AutoCloseable {
 
     override fun close() {
-        authorizationService?.dispose()
         okHttpClient.cache?.close()
     }
 
@@ -66,11 +63,11 @@ class HttpClient(
      */
     class Builder @Inject constructor(
         private val accountSettingsFactory: AccountSettings.Factory,
-        private val authorizationServiceProvider: Provider<AuthorizationService>,
         @ApplicationContext private val context: Context,
         defaultLogger: Logger,
         @IoDispatcher private val ioDispatcher: CoroutineDispatcher,
         private val keyManagerFactory: ClientCertKeyManager.Factory,
+        private val oAuthInterceptorFactory: OAuthInterceptor.Factory,
         private val settingsManager: SettingsManager
     ) {
 
@@ -97,14 +94,22 @@ class HttpClient(
 
         private var authenticationInterceptor: Interceptor? = null
         private var authenticator: Authenticator? = null
-        private var authorizationService: AuthorizationService? = null
         private var certificateAlias: String? = null
-        fun authenticate(host: String?, credentials: Credentials, authStateCallback: BearerAuthInterceptor.AuthStateUpdateCallback? = null): Builder {
+        fun authenticate(host: String?, getCredentials: () -> Credentials, updateAuthState: ((AuthState) -> Unit)? = null): Builder {
+            val credentials = getCredentials()
             if (credentials.authState != null) {
                 // OAuth
-                val authService = authorizationServiceProvider.get()
-                authenticationInterceptor = BearerAuthInterceptor.fromAuthState(authService, credentials.authState, authStateCallback)
-                authorizationService = authService
+                authenticationInterceptor = oAuthInterceptorFactory.create(
+                    readAuthState = {
+                        // We don't use the "credentials" object from above because it may contain an outdated access token
+                        // when readAuthState is called. Instead, we fetch the up-to-date auth-state.
+                        getCredentials().authState
+                    },
+                    writeAuthState = { authState ->
+                        updateAuthState?.invoke(authState)
+                    }
+
+                )
 
             } else if (credentials.username != null && credentials.password != null) {
                 // basic/digest auth
@@ -164,9 +169,11 @@ class HttpClient(
             val accountSettings = accountSettingsFactory.create(account)
             authenticate(
                 host = onlyHost,
-                credentials = accountSettings.credentials(),
-                authStateCallback = { authState: AuthState ->
-                    accountSettings.credentials(Credentials(authState = authState))
+                getCredentials = {
+                    accountSettings.credentials()
+                },
+                updateAuthState = { authState ->
+                    accountSettings.updateAuthState(authState)
                 }
             )
             return this
@@ -231,10 +238,7 @@ class HttpClient(
                 okBuilder.addNetworkInterceptor(loggingInterceptor)
             }
 
-            return HttpClient(
-                okHttpClient = okBuilder.build(),
-                authorizationService = authorizationService
-            )
+            return HttpClient(okBuilder.build())
         }
 
         private fun buildAuthentication(okBuilder: OkHttpClient.Builder) {
@@ -263,7 +267,7 @@ class HttpClient(
             val certManager = CustomCertManager(
                 context = context,
                 trustSystemCerts = !settingsManager.getBoolean(Settings.DISTRUST_SYSTEM_CERTIFICATES),
-                appInForeground = if (/* davx5-ose */ true)
+                appInForeground = if (BuildConfig.customCertsUI)
                     ForegroundTracker.inForeground  // interactive mode
                 else
                     null                            // non-interactive mode

app/src/main/kotlin/at/bitfire/davdroid/network/NextcloudLoginFlow.kt

@@ -6,7 +6,7 @@ package at.bitfire.davdroid.network
 
 import at.bitfire.dav4jvm.exception.DavException
 import at.bitfire.dav4jvm.exception.HttpException
-import at.bitfire.davdroid.db.Credentials
+import at.bitfire.davdroid.settings.Credentials
 import at.bitfire.davdroid.ui.setup.LoginInfo
 import at.bitfire.davdroid.util.withTrailingSlash
 import at.bitfire.vcard4android.GroupMethod
@@ -125,7 +125,7 @@ class NextcloudLoginFlow @Inject constructor(
         if (response.code != HttpURLConnection.HTTP_OK)
             throw HttpException(response)
 
-        response.body?.use { body ->
+        response.body.use { body ->
             val mimeType = body.contentType() ?: throw DavException("Login Flow response without MIME type")
             if (mimeType.type != "application" || mimeType.subtype != "json")
                 throw DavException("Invalid Login Flow response (not JSON)")
@@ -133,8 +133,6 @@ class NextcloudLoginFlow @Inject constructor(
             // decode JSON
             return@withContext JSONObject(body.string())
         }
-
-        throw DavException("Invalid Login Flow response (no body)")
     }
 
 }

app/src/main/kotlin/at/bitfire/davdroid/network/OAuthIntegration.kt

@@ -9,19 +9,14 @@ import android.content.Intent
 import androidx.activity.result.contract.ActivityResultContract
 import androidx.core.net.toUri
 import at.bitfire.davdroid.BuildConfig
-import at.bitfire.davdroid.db.Credentials
 import at.bitfire.davdroid.network.OAuthIntegration.redirectUri
 import kotlinx.coroutines.CompletableDeferred
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.withContext
 import net.openid.appauth.AuthState
 import net.openid.appauth.AuthorizationException
 import net.openid.appauth.AuthorizationRequest
 import net.openid.appauth.AuthorizationResponse
 import net.openid.appauth.AuthorizationService
-import net.openid.appauth.AuthorizationServiceConfiguration
 import net.openid.appauth.TokenResponse
-import java.util.Locale
 
 /**
  * Integration with OpenID AppAuth (Android)
@@ -38,42 +33,20 @@ object OAuthIntegration {
      * @param authService   authorization service
      * @param authResponse  response from the server (coming over the Intent from the browser / [AuthorizationContract])
      */
-    suspend fun authenticate(authService: AuthorizationService, authResponse: AuthorizationResponse): Credentials {
+    suspend fun authenticate(authService: AuthorizationService, authResponse: AuthorizationResponse): AuthState {
         val authState = AuthState(authResponse, null)       // authorization code must not be stored; exchange it to refresh token
-        val credentials = CompletableDeferred<Credentials>()
+        val authStateFuture = CompletableDeferred<AuthState>()
 
-        withContext(Dispatchers.IO) {
-            authService.performTokenRequest(authResponse.createTokenExchangeRequest()) { tokenResponse: TokenResponse?, refreshTokenException: AuthorizationException? ->
-                if (tokenResponse != null) {
-                    // success, save authState (= refresh token)
-                    authState.update(tokenResponse, refreshTokenException)
-                    credentials.complete(Credentials(authState = authState))
-                } else if (refreshTokenException != null)
-                    credentials.completeExceptionally(refreshTokenException)
-            }
+        authService.performTokenRequest(authResponse.createTokenExchangeRequest()) { tokenResponse: TokenResponse?, refreshTokenException: AuthorizationException? ->
+            if (tokenResponse != null) {
+                // success, save authState (= refresh token)
+                authState.update(tokenResponse, refreshTokenException)
+                authStateFuture.complete(authState)
+            } else if (refreshTokenException != null)
+                authStateFuture.completeExceptionally(refreshTokenException)
         }
 
-        return credentials.await()
-    }
-
-    /**
-     * Creates a new authorization request from a known configuration. Typically used to re-authorize
-     * from a given configuration.
-     *
-     * @param authConfig    current authorization config that shall be replaced
-     * @return authorization request, or `null` if the current config doesn't contain a known provider
-     */
-    fun newAuthorizeRequest(authConfig: AuthorizationServiceConfiguration): AuthorizationRequest? {
-        val authHost = authConfig.authorizationEndpoint.host.toString()
-        val locale = Locale.getDefault().toLanguageTag()
-
-        // If more OAuth providers become added, this should be rewritten so that all providers
-        // are checked automatically.
-        return when {
-            authHost.contains("fastmail.com") -> OAuthFastmail.signIn(null, locale)
-            authHost.contains("google.com") -> OAuthGoogle.signIn(null, null, locale)
-            else -> return null
-        }
+        return authStateFuture.await()
     }
 
 

app/src/main/kotlin/at/bitfire/davdroid/network/OAuthInterceptor.kt

@@ -0,0 +1,106 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.network
+
+import at.bitfire.davdroid.BuildConfig
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
+import net.openid.appauth.AuthState
+import net.openid.appauth.AuthorizationException
+import net.openid.appauth.AuthorizationService
+import okhttp3.Interceptor
+import okhttp3.Response
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.CompletionException
+import java.util.logging.Level
+import java.util.logging.Logger
+import javax.inject.Provider
+
+/**
+ * Sends an OAuth Bearer token authorization as described in RFC 6750.
+ *
+ * @param readAuthState     callback that fetches an up-to-date authorization state
+ * @param writeAuthState    callback that persists a new authorization state
+ */
+class OAuthInterceptor @AssistedInject constructor(
+    @Assisted private val readAuthState: () -> AuthState?,
+    @Assisted private val writeAuthState: (AuthState) -> Unit,
+    private val authServiceProvider: Provider<AuthorizationService>,
+    private val logger: Logger
+): Interceptor {
+
+    @AssistedFactory
+    interface Factory {
+        fun create(readAuthState: () -> AuthState?, writeAuthState: (AuthState) -> Unit): OAuthInterceptor
+    }
+
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val rq = chain.request().newBuilder()
+
+        /** Syntax for the "Authorization" header [RFC 6750 2.1]:
+         *
+         *      b64token    = 1*( ALPHA / DIGIT /
+         *                        "-" / "." / "_" / "~" / "+" / "/" ) *"="
+         *      credentials = "Bearer" 1*SP b64token
+         */
+
+        val accessToken = provideAccessToken()
+        if (accessToken != null)
+            rq.header("Authorization", "Bearer $accessToken")
+        else
+            logger.severe("No access token available, won't authenticate")
+
+        return chain.proceed(rq.build())
+    }
+
+    /**
+     * Provides a fresh access token for authorization. Uses the current one if it's still valid,
+     * or requests a new one if necessary.
+     *
+     * This method is synchronized / thread-safe so that it can be called for multiple HTTP requests at the same time.
+     *
+     * @return access token or `null` if no valid access token is available (usually because of an error during refresh)
+     */
+    fun provideAccessToken(): String? = synchronized(javaClass) {
+        // if possible, use cached access token
+        val authState = readAuthState() ?: return null
+
+        if (authState.isAuthorized && authState.accessToken != null && !authState.needsTokenRefresh) {
+            if (BuildConfig.DEBUG)      // log sensitive information (refresh/access token) only in debug builds
+                logger.log(Level.FINEST, "Using cached AuthState", authState.jsonSerializeString())
+            return authState.accessToken
+        }
+
+        // request fresh access token
+        logger.fine("Requesting fresh access token")
+        val accessTokenFuture = CompletableFuture<String>()
+        val authService = authServiceProvider.get()
+        try {
+            authState.performActionWithFreshTokens(authService) { accessToken: String?, _: String?, ex: AuthorizationException? ->
+                // appauth internally fetches the new token over HttpURLConnection in an AsyncTask
+                if (BuildConfig.DEBUG)
+                    logger.log(Level.FINEST, "Got new AuthState", authState.jsonSerializeString())
+
+                // persist updated AuthState
+                writeAuthState(authState)
+
+                if (ex != null)
+                    accessTokenFuture.completeExceptionally(ex)
+                else if (accessToken != null)
+                    accessTokenFuture.complete(accessToken)
+            }
+
+            accessTokenFuture.join()
+        } catch (e: CompletionException) {
+            logger.log(Level.SEVERE, "Couldn't obtain access token", e.cause)
+            null
+        } finally {
+            authService.dispose()
+        }
+    }
+
+}

app/src/main/kotlin/at/bitfire/davdroid/network/OAuthModule.kt

@@ -19,6 +19,12 @@ import java.net.URL
 @InstallIn(SingletonComponent::class)
 object OAuthModule {
 
+    /**
+     * Make sure to call [AuthorizationService.dispose] when obtaining an instance.
+     *
+     * Creating an instance is expensive (involves CustomTabsManager), so don't create an
+     * instance if not necessary (use Provider/Lazy).
+     */
     @Provides
     fun authorizationService(@ApplicationContext context: Context): AuthorizationService =
         AuthorizationService(context,

app/src/main/kotlin/at/bitfire/davdroid/repository/AccountRepository.kt

@@ -9,7 +9,6 @@ import android.accounts.AccountManager
 import android.accounts.OnAccountsUpdateListener
 import android.content.Context
 import at.bitfire.davdroid.R
-import at.bitfire.davdroid.db.Credentials
 import at.bitfire.davdroid.db.HomeSet
 import at.bitfire.davdroid.db.Service
 import at.bitfire.davdroid.db.ServiceType
@@ -18,6 +17,7 @@ import at.bitfire.davdroid.resource.LocalCalendarStore
 import at.bitfire.davdroid.servicedetection.DavResourceFinder
 import at.bitfire.davdroid.servicedetection.RefreshCollectionsWorker
 import at.bitfire.davdroid.settings.AccountSettings
+import at.bitfire.davdroid.settings.Credentials
 import at.bitfire.davdroid.sync.AutomaticSyncManager
 import at.bitfire.davdroid.sync.SyncDataType
 import at.bitfire.davdroid.sync.TasksAppManager

app/src/main/kotlin/at/bitfire/davdroid/repository/DavCollectionRepository.kt

@@ -23,6 +23,7 @@ import at.bitfire.dav4jvm.property.carddav.NS_CARDDAV
 import at.bitfire.dav4jvm.property.webdav.DisplayName
 import at.bitfire.dav4jvm.property.webdav.NS_WEBDAV
 import at.bitfire.dav4jvm.property.webdav.ResourceType
+import at.bitfire.davdroid.Constants
 import at.bitfire.davdroid.R
 import at.bitfire.davdroid.db.AppDatabase
 import at.bitfire.davdroid.db.Collection
@@ -32,8 +33,6 @@ import at.bitfire.davdroid.di.IoDispatcher
 import at.bitfire.davdroid.network.HttpClient
 import at.bitfire.davdroid.servicedetection.RefreshCollectionsWorker
 import at.bitfire.davdroid.util.DavUtils
-import at.bitfire.ical4android.ICalendar
-import at.bitfire.ical4android.util.DateUtils
 import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.runInterruptible
@@ -42,6 +41,7 @@ import net.fortuna.ical4j.model.Component
 import net.fortuna.ical4j.model.ComponentList
 import net.fortuna.ical4j.model.Property
 import net.fortuna.ical4j.model.PropertyList
+import net.fortuna.ical4j.model.TimeZoneRegistryFactory
 import net.fortuna.ical4j.model.component.VTimeZone
 import net.fortuna.ical4j.model.property.Version
 import okhttp3.HttpUrl
@@ -228,7 +228,7 @@ class DavCollectionRepository @Inject constructor(
      *
      * @param newCollection Collection to be inserted or updated
      */
-    fun insertOrUpdateByUrlAndRememberFlags(newCollection: Collection) {
+    fun insertOrUpdateByUrlRememberSync(newCollection: Collection) {
         db.runInTransaction {
             // remember locally set flags
             val oldCollection = dao.getByServiceAndUrl(newCollection.serviceId, newCollection.url.toString())
@@ -375,8 +375,8 @@ class DavCollectionRepository @Inject constructor(
                                         // spec requires "an iCalendar object with exactly one VTIMEZONE component"
                                         Calendar(
                                             PropertyList<Property>().apply {
-                                                add(ICalendar.prodId)
                                                 add(Version.VERSION_2_0)
+                                                add(Constants.iCalProdId)
                                             },
                                             ComponentList(
                                                 listOf(vTimezone)
@@ -417,6 +417,9 @@ class DavCollectionRepository @Inject constructor(
         return writer.toString()
     }
 
-    private fun getVTimeZone(tzId: String): VTimeZone? = DateUtils.ical4jTimeZone(tzId)?.vTimeZone
+    private fun getVTimeZone(tzId: String): VTimeZone? {
+        val tzRegistry = TimeZoneRegistryFactory.getInstance().createRegistry()
+        return tzRegistry.getTimeZone(tzId)?.vTimeZone
+    }
 
 }

app/src/main/kotlin/at/bitfire/davdroid/repository/DavHomeSetRepository.kt

@@ -5,7 +5,6 @@
 package at.bitfire.davdroid.repository
 
 import android.accounts.Account
-import androidx.room.Transaction
 import at.bitfire.davdroid.db.AppDatabase
 import at.bitfire.davdroid.db.HomeSet
 import at.bitfire.davdroid.db.Service
@@ -29,21 +28,8 @@ class DavHomeSetRepository @Inject constructor(
     fun getCalendarHomeSetsFlow(account: Account) =
         dao.getBindableByAccountAndServiceTypeFlow(account.name, Service.TYPE_CALDAV)
 
-
-    /**
-     * Tries to insert new row, but updates existing row if already present.
-     * This method preserves the primary key, as opposed to using "@Insert(onConflict = OnConflictStrategy.REPLACE)"
-     * which will create a new row with incremented ID and thus breaks entity relationships!
-     *
-     * @return ID of the row, that has been inserted or updated. -1 If the insert fails due to other reasons.
-     */
-    @Transaction
-    fun insertOrUpdateByUrlBlocking(homeset: HomeSet): Long =
-        dao.getByUrl(homeset.serviceId, homeset.url.toString())?.let { existingHomeset ->
-            dao.update(homeset.copy(id = existingHomeset.id))
-            existingHomeset.id
-        } ?: dao.insert(homeset)
-
+    fun insertOrUpdateByUrlBlocking(homeSet: HomeSet): Long =
+        dao.insertOrUpdateByUrlBlocking(homeSet)
 
     fun deleteBlocking(homeSet: HomeSet) = dao.delete(homeSet)
 

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalAddressBook.kt

@@ -17,19 +17,20 @@ import android.provider.ContactsContract.RawContacts
 import androidx.annotation.OpenForTesting
 import androidx.core.content.contentValuesOf
 import at.bitfire.davdroid.R
-import at.bitfire.davdroid.db.SyncState
 import at.bitfire.davdroid.repository.DavCollectionRepository
 import at.bitfire.davdroid.repository.DavServiceRepository
 import at.bitfire.davdroid.resource.LocalAddressBook.Companion.USER_DATA_READ_ONLY
 import at.bitfire.davdroid.resource.workaround.ContactDirtyVerifier
 import at.bitfire.davdroid.settings.AccountSettings
-import at.bitfire.davdroid.sync.SyncFrameworkIntegration
+import at.bitfire.davdroid.sync.SyncDataType
 import at.bitfire.davdroid.sync.account.SystemAccountUtils
 import at.bitfire.davdroid.sync.account.setAndVerifyUserData
+import at.bitfire.davdroid.sync.adapter.SyncFrameworkIntegration
+import at.bitfire.synctools.storage.BatchOperation
+import at.bitfire.synctools.storage.ContactsBatchOperation
 import at.bitfire.vcard4android.AndroidAddressBook
 import at.bitfire.vcard4android.AndroidContact
 import at.bitfire.vcard4android.AndroidGroup
-import at.bitfire.vcard4android.BatchOperation
 import at.bitfire.vcard4android.GroupMethod
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory
@@ -198,17 +199,17 @@ open class LocalAddressBook @AssistedInject constructor(
             return false
 
         // move contacts and groups to new account
-        val batch = BatchOperation(provider!!)
-        batch.enqueue(BatchOperation.CpoBuilder
+        val batch = ContactsBatchOperation(provider!!)
+        batch += BatchOperation.CpoBuilder
             .newUpdate(groupsSyncUri())
             .withSelection(Groups.ACCOUNT_NAME + "=? AND " + Groups.ACCOUNT_TYPE + "=?", arrayOf(oldAccount.name, oldAccount.type))
             .withValue(Groups.ACCOUNT_NAME, newAccount.name)
-        )
-        batch.enqueue(BatchOperation.CpoBuilder
+            .withValue(Groups.ACCOUNT_TYPE, newAccount.type)
+        batch += BatchOperation.CpoBuilder
             .newUpdate(rawContactsSyncUri())
             .withSelection(RawContacts.ACCOUNT_NAME + "=? AND " + RawContacts.ACCOUNT_TYPE + "=?", arrayOf(oldAccount.name, oldAccount.type))
             .withValue(RawContacts.ACCOUNT_NAME, newAccount.name)
-        )
+            .withValue(RawContacts.ACCOUNT_TYPE, newAccount.type)
         batch.commit()
 
         // update AndroidAddressBook.account
@@ -222,15 +223,18 @@ open class LocalAddressBook @AssistedInject constructor(
 
 
     /**
-     * Makes contacts of this address book available to be synced and activates synchronization upon
-     * contact data changes.
+     * Enables or disables sync on content changes for the address book account based on the current sync
+     * interval account setting.
      */
     fun updateSyncFrameworkSettings() {
-        // Enable sync-ability of contacts
-        syncFramework.enableSyncAbility(addressBookAccount, ContactsContract.AUTHORITY)
+        val accountSettings = accountSettingsFactory.create(account)
+        val syncInterval = accountSettings.getSyncInterval(SyncDataType.CONTACTS)
 
-        // Changes in contact data should trigger syncs
-        syncFramework.enableSyncOnContentChange(addressBookAccount, ContactsContract.AUTHORITY)
+        // Enable/Disable content triggered syncs for the address book account.
+        if (syncInterval != null)
+            syncFramework.enableSyncOnContentChange(addressBookAccount, ContactsContract.AUTHORITY)
+        else
+            syncFramework.disableSyncOnContentChange(addressBookAccount, ContactsContract.AUTHORITY)
     }
 
 

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalAddressBookStore.kt

@@ -6,6 +6,7 @@ package at.bitfire.davdroid.resource
 
 import android.accounts.Account
 import android.accounts.AccountManager
+import android.accounts.OnAccountsUpdateListener
 import android.content.ContentProviderClient
 import android.content.Context
 import android.provider.ContactsContract
@@ -23,6 +24,9 @@ import at.bitfire.davdroid.sync.account.setAndVerifyUserData
 import at.bitfire.davdroid.util.DavUtils.lastSegment
 import com.google.common.base.CharMatcher
 import dagger.hilt.android.qualifiers.ApplicationContext
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
 import java.util.logging.Level
 import java.util.logging.Logger
 import javax.inject.Inject
@@ -74,8 +78,14 @@ class LocalAddressBookStore @Inject constructor(
         return sb.toString()
     }
 
-    override fun acquireContentProvider() =
+    override fun acquireContentProvider(throwOnMissingPermissions: Boolean) = try {
         context.contentResolver.acquireContentProviderClient(authority)
+    } catch (e: SecurityException) {
+        if (throwOnMissingPermissions)
+            throw e
+        else
+            /* return */ null
+    }
 
     override fun create(provider: ContentProviderClient, fromCollection: Collection): LocalAddressBook? {
         val service = serviceRepository.getBlocking(fromCollection.serviceId) ?: throw IllegalArgumentException("Couldn't fetch DB service from collection")
@@ -115,17 +125,10 @@ class LocalAddressBookStore @Inject constructor(
         return addressBookAccount
     }
 
-    override fun getAll(account: Account, provider: ContentProviderClient): List<LocalAddressBook> {
-        val accountManager = AccountManager.get(context)
-        return accountManager.getAccountsByType(context.getString(R.string.account_type_address_book))
-            .filter { addressBookAccount ->
-                accountManager.getUserData(addressBookAccount, LocalAddressBook.USER_DATA_ACCOUNT_NAME) == account.name &&
-                accountManager.getUserData(addressBookAccount, LocalAddressBook.USER_DATA_ACCOUNT_TYPE) == account.type
-            }
-            .map { addressBookAccount ->
-                localAddressBookFactory.create(account, addressBookAccount, provider)
-            }
-    }
+    override fun getAll(account: Account, provider: ContentProviderClient): List<LocalAddressBook> =
+        getAddressBookAccounts(account).map { addressBookAccount ->
+            localAddressBookFactory.create(account, addressBookAccount, provider)
+        }
 
     override fun update(provider: ContentProviderClient, localCollection: LocalAddressBook, fromCollection: Collection) {
         var currentAccount = localCollection.addressBookAccount
@@ -155,7 +158,7 @@ class LocalAddressBookStore @Inject constructor(
             localCollection.readOnly = nowReadOnly
         }
 
-        // make sure it will still be synchronized when contacts are updated
+        // Update automatic synchronization
         localCollection.updateSyncFrameworkSettings()
     }
 
@@ -197,6 +200,45 @@ class LocalAddressBookStore @Inject constructor(
             accountManager.removeAccountExplicitly(addressBookAccount)
     }
 
+    /**
+     * Returns all address book accounts that belong to the given account.
+     *
+     * @param account    Account which has the address books.
+     * @return List of address book accounts.
+     */
+    fun getAddressBookAccounts(account: Account): List<Account> =
+        AccountManager.get(context).let { accountManager ->
+            accountManager.getAccountsByType(context.getString(R.string.account_type_address_book))
+                .filter { addressBookAccount ->
+                    account.name == accountManager.getUserData(
+                        addressBookAccount,
+                        LocalAddressBook.USER_DATA_ACCOUNT_NAME
+                    ) && account.type == accountManager.getUserData(
+                        addressBookAccount,
+                        LocalAddressBook.USER_DATA_ACCOUNT_TYPE
+                    )
+                }
+        }
+
+    /**
+     * Returns all address book accounts that belong to the given account in a flow.
+     *
+     * @param account    Account which has the address books.
+     * @return List of address book accounts as flow.
+     */
+    fun getAddressBookAccountsFlow(account: Account): Flow<List<Account>> = callbackFlow {
+        val accountManager = AccountManager.get(context)
+        val listener = OnAccountsUpdateListener { accounts ->
+            trySend(getAddressBookAccounts(account))
+        }
+        accountManager.addOnAccountsUpdatedListener(
+            /* listener = */ listener,
+            /* handler = */ null,
+            /* updateImmediately = */ true
+        )
+        awaitClose { accountManager.removeOnAccountsUpdatedListener(listener) }
+    }
+
 
     companion object {
 

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalCalendar.kt

@@ -4,20 +4,22 @@
 
 package at.bitfire.davdroid.resource
 
-import android.accounts.Account
-import android.content.ContentProviderClient
 import android.content.ContentUris
-import android.content.ContentValues
 import android.provider.CalendarContract.Calendars
 import android.provider.CalendarContract.Events
 import androidx.core.content.contentValuesOf
-import at.bitfire.davdroid.db.SyncState
-import at.bitfire.ical4android.AndroidCalendar
-import at.bitfire.ical4android.AndroidCalendarFactory
-import at.bitfire.ical4android.BatchOperation
+import at.bitfire.ical4android.Event
 import at.bitfire.ical4android.util.MiscUtils.asSyncAdapter
+import at.bitfire.synctools.mapping.calendar.LegacyAndroidEventBuilder2
+import at.bitfire.synctools.storage.BatchOperation
+import at.bitfire.synctools.storage.calendar.AndroidCalendar
+import at.bitfire.synctools.storage.calendar.AndroidEvent2
+import at.bitfire.synctools.storage.calendar.AndroidRecurringCalendar
+import at.bitfire.synctools.storage.calendar.CalendarBatchOperation
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
 import java.util.LinkedList
-import java.util.logging.Level
 import java.util.logging.Logger
 
 /**
@@ -25,55 +27,62 @@ import java.util.logging.Logger
  *
  * [Calendars._SYNC_ID] corresponds to the database collection ID ([at.bitfire.davdroid.db.Collection.id]).
  */
-class LocalCalendar private constructor(
-    account: Account,
-    provider: ContentProviderClient,
-    id: Long
-): AndroidCalendar<LocalEvent>(account, provider, LocalEvent.Factory, id), LocalCollection<LocalEvent> {
-
-    companion object {
-
-        private const val COLUMN_SYNC_STATE = Calendars.CAL_SYNC1
-
-        private val logger: Logger
-            get() = Logger.getGlobal()
+class LocalCalendar @AssistedInject constructor(
+    @Assisted internal val androidCalendar: AndroidCalendar,
+    private val logger: Logger
+) : LocalCollection<LocalEvent> {
 
+    @AssistedFactory
+    interface Factory {
+        fun create(calendar: AndroidCalendar): LocalCalendar
     }
 
+
+    // properties
+
     override val dbCollectionId: Long?
-        get() = syncId?.toLongOrNull()
+        get() = androidCalendar.syncId?.toLongOrNull()
 
     override val tag: String
-        get() = "events-${account.name}-$id"
+        get() = "events-${androidCalendar.account.name}-${androidCalendar.id}"
 
     override val title: String
-        get() = displayName ?: id.toString()
+        get() = androidCalendar.displayName ?: androidCalendar.id.toString()
 
-    private var accessLevel: Int = Calendars.CAL_ACCESS_OWNER   // assume full access if not specified
     override val readOnly
-        get() = accessLevel <= Calendars.CAL_ACCESS_READ
+        get() = androidCalendar.accessLevel <= Calendars.CAL_ACCESS_READ
 
     override var lastSyncState: SyncState?
-        get() = provider.query(calendarSyncURI(), arrayOf(COLUMN_SYNC_STATE), null, null, null)?.use { cursor ->
-                    if (cursor.moveToNext())
-                        return SyncState.fromString(cursor.getString(0))
-                    else
-                        null
-                }
+        get() = androidCalendar.readSyncState()?.let {
+            SyncState.fromString(it)
+        }
         set(state) {
-            val values = contentValuesOf(COLUMN_SYNC_STATE to state.toString())
-            provider.update(calendarSyncURI(), values, null, null)
+            androidCalendar.writeSyncState(state.toString())
         }
 
+    private val recurringCalendar = AndroidRecurringCalendar(androidCalendar)
 
-    override fun populate(info: ContentValues) {
-        super.populate(info)
-        accessLevel = info.getAsInteger(Calendars.CALENDAR_ACCESS_LEVEL) ?: Calendars.CAL_ACCESS_OWNER
+
+    fun add(event: Event, fileName: String, eTag: String?, scheduleTag: String?, flags: Int) {
+        val mapped = LegacyAndroidEventBuilder2(
+            calendar = androidCalendar,
+            event = event,
+            id = null,
+            syncId = fileName,
+            eTag = eTag,
+            scheduleTag = scheduleTag,
+            flags = flags
+        ).build()
+        recurringCalendar.addEventAndExceptions(mapped)
     }
 
-
-    override fun findDeleted() =
-        queryEvents("${Events.DELETED} AND ${Events.ORIGINAL_ID} IS NULL", null)
+    override fun findDeleted(): List<LocalEvent> {
+        val result = LinkedList<LocalEvent>()
+        androidCalendar.iterateEvents( "${Events.DELETED} AND ${Events.ORIGINAL_ID} IS NULL", null) { entity ->
+            result += LocalEvent(recurringCalendar, AndroidEvent2(androidCalendar, entity))
+        }
+        return result
+    }
 
     override fun findDirty(): List<LocalEvent> {
         val dirty = LinkedList<LocalEvent>()
@@ -83,129 +92,119 @@ class LocalCalendar private constructor(
          * When a calendar component is created, its sequence number is 0. It is monotonically incremented by the "Organizer's"
          * CUA each time the "Organizer" makes a significant revision to the calendar component.
          */
-        for (localEvent in queryEvents("${Events.DIRTY} AND ${Events.ORIGINAL_ID} IS NULL", null)) {
-            try {
-                val event = requireNotNull(localEvent.event)
-
-                val nonGroupScheduled = event.attendees.isEmpty()
-                val weAreOrganizer = localEvent.weAreOrganizer
-
-                val sequence = event.sequence
-                if (sequence == null)
-                    // sequence has not been assigned yet (i.e. this event was just locally created)
-                    event.sequence = 0
-                else if (nonGroupScheduled || weAreOrganizer)   // increase sequence
-                    event.sequence = sequence + 1
-
-            } catch(e: Exception) {
-                logger.log(Level.WARNING, "Couldn't check/increase sequence", e)
-            }
-            dirty += localEvent
+        androidCalendar.iterateEvents("${Events.DIRTY} AND ${Events.ORIGINAL_ID} IS NULL", null) { values ->
+            dirty += LocalEvent(recurringCalendar, AndroidEvent2(androidCalendar, values))
         }
 
         return dirty
     }
 
     override fun findByName(name: String) =
-            queryEvents("${Events._SYNC_ID}=?", arrayOf(name)).firstOrNull()
+        androidCalendar.findEvent("${Events._SYNC_ID}=? AND ${Events.ORIGINAL_SYNC_ID} IS null", arrayOf(name))?.let {
+            LocalEvent(recurringCalendar, it)
+        }
 
-
-    override fun markNotDirty(flags: Int): Int {
-        val values = contentValuesOf(LocalEvent.COLUMN_FLAGS to flags)
-        return provider.update(Events.CONTENT_URI.asSyncAdapter(account), values,
-                "${Events.CALENDAR_ID}=? AND NOT ${Events.DIRTY} AND ${Events.ORIGINAL_ID} IS NULL",
-                arrayOf(id.toString()))
-    }
+    override fun markNotDirty(flags: Int) =
+        androidCalendar.updateEventRows(
+            contentValuesOf(AndroidEvent2.COLUMN_FLAGS to flags),
+            // `dirty` can be 0, 1, or null. "NOT dirty" is not enough.
+            """
+                ${Events.CALENDAR_ID}=?
+                AND (${Events.DIRTY} IS NULL OR ${Events.DIRTY}=0)
+                AND ${Events.ORIGINAL_ID} IS NULL
+            """.trimIndent(),
+            arrayOf(androidCalendar.id.toString())
+        )
 
     override fun removeNotDirtyMarked(flags: Int): Int {
-        var deleted = 0
         // list all non-dirty events with the given flags and delete every row + its exceptions
-        provider.query(Events.CONTENT_URI.asSyncAdapter(account), arrayOf(Events._ID),
-                "${Events.CALENDAR_ID}=? AND NOT ${Events.DIRTY} AND ${Events.ORIGINAL_ID} IS NULL AND ${LocalEvent.COLUMN_FLAGS}=?",
-                arrayOf(id.toString(), flags.toString()), null)?.use { cursor ->
-            val batch = BatchOperation(provider)
-            while (cursor.moveToNext()) {
-                val id = cursor.getLong(0)
-                // delete event and possible exceptions (content provider doesn't delete exceptions itself)
-                batch.enqueue(BatchOperation.CpoBuilder
-                        .newDelete(Events.CONTENT_URI.asSyncAdapter(account))
-                        .withSelection("${Events._ID}=? OR ${Events.ORIGINAL_ID}=?", arrayOf(id.toString(), id.toString())))
-            }
-            deleted = batch.commit()
+        val batch = CalendarBatchOperation(androidCalendar.client)
+        androidCalendar.iterateEventRows(
+            arrayOf(Events._ID),
+            // `dirty` can be 0, 1, or null. "NOT dirty" is not enough.
+            """
+                ${Events.CALENDAR_ID}=?
+                AND (${Events.DIRTY} IS NULL OR ${Events.DIRTY}=0)
+                AND ${Events.ORIGINAL_ID} IS NULL
+                AND ${AndroidEvent2.COLUMN_FLAGS}=?
+            """.trimIndent(),
+            arrayOf(androidCalendar.id.toString(), flags.toString())
+        ) { values ->
+            val id = values.getAsLong(Events._ID)
+
+            // delete event and possible exceptions (content provider doesn't delete exceptions itself)
+            batch += BatchOperation.CpoBuilder
+                .newDelete(androidCalendar.eventsUri)
+                .withSelection("${Events._ID}=? OR ${Events.ORIGINAL_ID}=?", arrayOf(id.toString(), id.toString()))
         }
-        return deleted
+        return batch.commit()
     }
 
     override fun forgetETags() {
-        val values = contentValuesOf(LocalEvent.COLUMN_ETAG to null)
-        provider.update(Events.CONTENT_URI.asSyncAdapter(account), values, "${Events.CALENDAR_ID}=?",
-                arrayOf(id.toString()))
+        androidCalendar.updateEventRows(
+            contentValuesOf(AndroidEvent2.COLUMN_ETAG to null),
+            "${Events.CALENDAR_ID}=?", arrayOf(androidCalendar.id.toString())
+        )
     }
 
 
     fun processDirtyExceptions() {
         // process deleted exceptions
         logger.info("Processing deleted exceptions")
-        provider.query(
-                Events.CONTENT_URI.asSyncAdapter(account),
-                arrayOf(Events._ID, Events.ORIGINAL_ID, LocalEvent.COLUMN_SEQUENCE),
-                "${Events.CALENDAR_ID}=? AND ${Events.DELETED} AND ${Events.ORIGINAL_ID} IS NOT NULL",
-                arrayOf(id.toString()), null)?.use { cursor ->
-            while (cursor.moveToNext()) {
-                logger.fine("Found deleted exception, removing and re-scheduling original event (if available)")
-                val id = cursor.getLong(0)             // can't be null (by definition)
-                val originalID = cursor.getLong(1)     // can't be null (by query)
 
-                val batch = BatchOperation(provider)
+        androidCalendar.iterateEventRows(
+            arrayOf(Events._ID, Events.ORIGINAL_ID, AndroidEvent2.COLUMN_SEQUENCE),
+            "${Events.CALENDAR_ID}=? AND ${Events.DELETED} AND ${Events.ORIGINAL_ID} IS NOT NULL",
+            arrayOf(androidCalendar.id.toString())
+        ) { values ->
+            logger.fine("Found deleted exception, removing and re-scheduling original event (if available)")
 
-                // get original event's SEQUENCE
-                provider.query(
-                        ContentUris.withAppendedId(Events.CONTENT_URI, originalID).asSyncAdapter(account),
-                        arrayOf(LocalEvent.COLUMN_SEQUENCE),
-                        null, null, null)?.use { cursor2 ->
-                    if (cursor2.moveToNext()) {
-                        // original event is available
-                        val originalSequence = if (cursor2.isNull(0)) 0 else cursor2.getInt(0)
+            val id = values.getAsLong(Events._ID)                   // can't be null (by definition)
+            val originalID = values.getAsLong(Events.ORIGINAL_ID)   // can't be null (by query)
 
-                        // re-schedule original event and set it to DIRTY
-                        batch.enqueue(BatchOperation.CpoBuilder
-                                .newUpdate(ContentUris.withAppendedId(Events.CONTENT_URI, originalID).asSyncAdapter(account))
-                                .withValue(LocalEvent.COLUMN_SEQUENCE, originalSequence + 1)
-                                .withValue(Events.DIRTY, 1))
-                    }
-                }
+            val batch = CalendarBatchOperation(androidCalendar.client)
 
-                // completely remove deleted exception
-                batch.enqueue(BatchOperation.CpoBuilder.newDelete(ContentUris.withAppendedId(Events.CONTENT_URI, id).asSyncAdapter(account)))
-                batch.commit()
-            }
+            // enqueue: increase sequence of main event
+            val originalEventValues = androidCalendar.getEventRow(originalID, arrayOf(AndroidEvent2.COLUMN_SEQUENCE))
+            val originalSequence = originalEventValues?.getAsInteger(AndroidEvent2.COLUMN_SEQUENCE) ?: 0
+
+            batch += BatchOperation.CpoBuilder
+                .newUpdate(ContentUris.withAppendedId(Events.CONTENT_URI, originalID).asSyncAdapter(androidCalendar.account))
+                .withValue(AndroidEvent2.COLUMN_SEQUENCE, originalSequence + 1)
+                .withValue(Events.DIRTY, 1)
+
+            // completely remove deleted exception
+            batch += BatchOperation.CpoBuilder.newDelete(ContentUris.withAppendedId(Events.CONTENT_URI, id).asSyncAdapter(androidCalendar.account))
+            batch.commit()
         }
 
         // process dirty exceptions
         logger.info("Processing dirty exceptions")
-        provider.query(
-                Events.CONTENT_URI.asSyncAdapter(account),
-                arrayOf(Events._ID, Events.ORIGINAL_ID, LocalEvent.COLUMN_SEQUENCE),
-                "${Events.CALENDAR_ID}=? AND ${Events.DIRTY} AND ${Events.ORIGINAL_ID} IS NOT NULL",
-                arrayOf(id.toString()), null)?.use { cursor ->
-            while (cursor.moveToNext()) {
-                logger.fine("Found dirty exception, increasing SEQUENCE to re-schedule")
-                val id = cursor.getLong(0)             // can't be null (by definition)
-                val originalID = cursor.getLong(1)     // can't be null (by query)
-                val sequence = if (cursor.isNull(2)) 0 else cursor.getInt(2)
+        androidCalendar.iterateEventRows(
+            arrayOf(Events._ID, Events.ORIGINAL_ID, AndroidEvent2.COLUMN_SEQUENCE),
+            "${Events.CALENDAR_ID}=? AND ${Events.DIRTY} AND ${Events.ORIGINAL_ID} IS NOT NULL",
+            arrayOf(androidCalendar.id.toString())
+        ) { values ->
+            logger.fine("Found dirty exception, increasing SEQUENCE to re-schedule")
 
-                val batch = BatchOperation(provider)
-                // original event to DIRTY
-                batch.enqueue(BatchOperation.CpoBuilder
-                        .newUpdate(ContentUris.withAppendedId(Events.CONTENT_URI, originalID).asSyncAdapter(account))
-                        .withValue(Events.DIRTY, 1))
-                // increase SEQUENCE and set DIRTY to 0
-                batch.enqueue(BatchOperation.CpoBuilder
-                        .newUpdate(ContentUris.withAppendedId(Events.CONTENT_URI, id).asSyncAdapter(account))
-                        .withValue(LocalEvent.COLUMN_SEQUENCE, sequence + 1)
-                        .withValue(Events.DIRTY, 0))
-                batch.commit()
-            }
+            val id = values.getAsLong(Events._ID)                   // can't be null (by definition)
+            val originalID = values.getAsLong(Events.ORIGINAL_ID)   // can't be null (by query)
+            val sequence = values.getAsInteger(AndroidEvent2.COLUMN_SEQUENCE) ?: 0
+
+            val batch = CalendarBatchOperation(androidCalendar.client)
+
+            // enqueue: set original event to DIRTY
+            batch += BatchOperation.CpoBuilder
+                .newUpdate(androidCalendar.eventUri(originalID))
+                .withValue(Events.DIRTY, 1)
+
+            // enqueue: increase exception SEQUENCE and set DIRTY to 0
+            batch += BatchOperation.CpoBuilder
+                .newUpdate(androidCalendar.eventUri(id))
+                .withValue(AndroidEvent2.COLUMN_SEQUENCE, sequence + 1)
+                .withValue(Events.DIRTY, 0)
+
+            batch.commit()
         }
     }
 
@@ -215,33 +214,23 @@ class LocalCalendar private constructor(
      * @return number of affected events
      */
     fun deleteDirtyEventsWithoutInstances() {
-        provider.query(
-            Events.CONTENT_URI.asSyncAdapter(account),
+        // Iterate dirty main events without exceptions
+        androidCalendar.iterateEventRows(
             arrayOf(Events._ID),
-            "${Events.DIRTY} AND NOT ${Events.DELETED} AND ${Events.ORIGINAL_ID} IS NULL",    // Get dirty main events (and no exception events)
-            null, null
-        )?.use { cursor ->
-            while (cursor.moveToNext()) {
-                val eventID = cursor.getLong(0)
+            "${Events.DIRTY} AND NOT ${Events.DELETED} AND ${Events.ORIGINAL_ID} IS NULL",
+            null
+        ) { values ->
+            val eventId = values.getAsLong(Events._ID)
 
-                // get number of instances
-                val numEventInstances = LocalEvent.numInstances(provider, account, eventID)
+            // get number of instances
+            val numEventInstances = androidCalendar.numInstances(eventId)
 
-                // delete event if there are no instances
-                if (numEventInstances == 0) {
-                    logger.info("Marking event #$eventID without instances as deleted")
-                    LocalEvent.markAsDeleted(provider, account, eventID)
-                }
+            // delete event if there are no instances
+            if (numEventInstances == 0) {
+                logger.fine("Marking event #$eventId without instances as deleted")
+                androidCalendar.updateEventRow(eventId, contentValuesOf(Events.DELETED to 1))
             }
         }
     }
 
-
-    object Factory: AndroidCalendarFactory<LocalCalendar> {
-
-        override fun newInstance(account: Account, provider: ContentProviderClient, id: Long) =
-            LocalCalendar(account, provider, id)
-
-    }
-
 }

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalCalendarStore.kt

@@ -6,11 +6,13 @@ package at.bitfire.davdroid.resource
 
 import android.accounts.Account
 import android.content.ContentProviderClient
-import android.content.ContentUris
 import android.content.ContentValues
 import android.content.Context
 import android.provider.CalendarContract
+import android.provider.CalendarContract.Attendees
 import android.provider.CalendarContract.Calendars
+import android.provider.CalendarContract.Events
+import android.provider.CalendarContract.Reminders
 import androidx.core.content.contentValuesOf
 import at.bitfire.davdroid.Constants
 import at.bitfire.davdroid.R
@@ -18,10 +20,9 @@ import at.bitfire.davdroid.db.Collection
 import at.bitfire.davdroid.repository.DavServiceRepository
 import at.bitfire.davdroid.settings.AccountSettings
 import at.bitfire.davdroid.util.DavUtils.lastSegment
-import at.bitfire.ical4android.AndroidCalendar
-import at.bitfire.ical4android.AndroidCalendar.Companion.calendarBaseValues
 import at.bitfire.ical4android.util.DateUtils
 import at.bitfire.ical4android.util.MiscUtils.asSyncAdapter
+import at.bitfire.synctools.storage.calendar.AndroidCalendarProvider
 import dagger.hilt.android.qualifiers.ApplicationContext
 import java.util.logging.Level
 import java.util.logging.Logger
@@ -30,6 +31,7 @@ import javax.inject.Inject
 class LocalCalendarStore @Inject constructor(
     @ApplicationContext private val context: Context,
     private val accountSettingsFactory: AccountSettings.Factory,
+    private val localCalendarFactory: LocalCalendar.Factory,
     private val logger: Logger,
     private val serviceRepository: DavServiceRepository
 ): LocalDataStore<LocalCalendar> {
@@ -37,10 +39,16 @@ class LocalCalendarStore @Inject constructor(
     override val authority: String
         get() = CalendarContract.AUTHORITY
 
-    override fun acquireContentProvider() =
+    override fun acquireContentProvider(throwOnMissingPermissions: Boolean) = try {
         context.contentResolver.acquireContentProviderClient(authority)
+    } catch (e: SecurityException) {
+        if (throwOnMissingPermissions)
+            throw e
+        else
+            /* return */ null
+    }
 
-    override fun create(provider: ContentProviderClient, fromCollection: Collection): LocalCalendar? {
+    override fun create(client: ContentProviderClient, fromCollection: Collection): LocalCalendar? {
         val service = serviceRepository.getBlocking(fromCollection.serviceId) ?: throw IllegalArgumentException("Couldn't fetch DB service from collection")
         val account = Account(service.accountName, context.getString(R.string.account_type))
 
@@ -69,26 +77,49 @@ class LocalCalendarStore @Inject constructor(
         }
 
         logger.log(Level.INFO, "Adding local calendar", values)
-        val uri = AndroidCalendar.create(account, provider, values)
-        return AndroidCalendar.findByID(account, provider, LocalCalendar.Factory, ContentUris.parseId(uri))
+        val provider = AndroidCalendarProvider(account, client)
+        return localCalendarFactory.create(provider.createAndGetCalendar(values))
     }
 
-    override fun getAll(account: Account, provider: ContentProviderClient) =
-        AndroidCalendar.find(account, provider, LocalCalendar.Factory, "${Calendars.SYNC_EVENTS}!=0", null)
+    override fun getAll(account: Account, client: ContentProviderClient) =
+        AndroidCalendarProvider(account, client)
+            .findCalendars("${Calendars.SYNC_EVENTS}!=0", null)
+            .map { localCalendarFactory.create(it) }
 
-    override fun update(provider: ContentProviderClient, localCollection: LocalCalendar, fromCollection: Collection) {
-        val accountSettings = accountSettingsFactory.create(localCollection.account)
+    override fun update(client: ContentProviderClient, localCollection: LocalCalendar, fromCollection: Collection) {
+        val accountSettings = accountSettingsFactory.create(localCollection.androidCalendar.account)
         val values = valuesFromCollectionInfo(fromCollection, withColor = accountSettings.getManageCalendarColors())
 
         logger.log(Level.FINE, "Updating local calendar ${fromCollection.url}", values)
-        localCollection.update(values)
+        val androidCalendar = localCollection.androidCalendar
+        val provider = AndroidCalendarProvider(androidCalendar.account, client)
+        provider.updateCalendar(androidCalendar.id, values)
     }
 
     private fun valuesFromCollectionInfo(info: Collection, withColor: Boolean): ContentValues {
-        val values = ContentValues()
-        values.put(Calendars._SYNC_ID, info.id)
-        values.put(Calendars.CALENDAR_DISPLAY_NAME,
-            if (info.displayName.isNullOrBlank()) info.url.lastSegment else info.displayName)
+        val values = contentValuesOf(
+            Calendars._SYNC_ID to info.id,
+            Calendars.CALENDAR_DISPLAY_NAME to
+                    if (info.displayName.isNullOrBlank()) info.url.lastSegment else info.displayName,
+
+            Calendars.ALLOWED_AVAILABILITY to arrayOf(
+                Events.AVAILABILITY_BUSY,
+                Events.AVAILABILITY_FREE
+            ).joinToString(",") { it.toString() },
+
+            Calendars.ALLOWED_ATTENDEE_TYPES to arrayOf(
+                Attendees.TYPE_NONE,
+                Attendees.TYPE_OPTIONAL,
+                Attendees.TYPE_REQUIRED,
+                Attendees.TYPE_RESOURCE
+            ).joinToString(",") { it.toString() },
+
+            Calendars.ALLOWED_REMINDERS to arrayOf(
+                Reminders.METHOD_DEFAULT,
+                Reminders.METHOD_ALERT,
+                Reminders.METHOD_EMAIL
+            ).joinToString(",") { it.toString() },
+        )
 
         if (withColor && info.color != null)
             values.put(Calendars.CALENDAR_COLOR, info.color)
@@ -104,9 +135,6 @@ class LocalCalendarStore @Inject constructor(
             values.put(Calendars.CALENDAR_TIME_ZONE, DateUtils.findAndroidTimezoneID(tzId))
         }
 
-        // add base values for Calendars
-        values.putAll(calendarBaseValues)
-
         return values
     }
 
@@ -120,7 +148,7 @@ class LocalCalendarStore @Inject constructor(
 
     override fun delete(localCollection: LocalCalendar) {
         logger.log(Level.INFO, "Deleting local calendar", localCollection)
-        localCollection.delete()
+        localCollection.androidCalendar.delete()
     }
 
-}
+}

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalCollection.kt

@@ -4,8 +4,6 @@
 
 package at.bitfire.davdroid.resource
 
-import at.bitfire.davdroid.db.SyncState
-
 interface LocalCollection<out T: LocalResource<*>> {
 
     /** a tag that uniquely identifies the collection (DAVx5-wide) */
@@ -50,10 +48,8 @@ interface LocalCollection<out T: LocalResource<*>> {
      */
     fun findByName(name: String): T?
 
-
     /**
-     * Sets the [LocalEvent.COLUMN_FLAGS] value for entries which are not dirty ([Events.DIRTY] is 0)
-     * and have an [Events.ORIGINAL_ID] of null.
+     * Updates the flags value for entries which are not dirty.
      *
      * @param flags    value of flags to set (for instance, [LocalResource.FLAG_REMOTELY_PRESENT]])
      *
@@ -62,8 +58,7 @@ interface LocalCollection<out T: LocalResource<*>> {
     fun markNotDirty(flags: Int): Int
 
     /**
-     * Removes entries which are not dirty ([Events.DIRTY] is 0 and an [Events.ORIGINAL_ID] is null) with
-     * a given flag combination.
+     * Removes entries which are not dirty with a given flag combination.
      *
      * @param flags    exact flags value to remove entries with (for instance, if this is [LocalResource.FLAG_REMOTELY_PRESENT]],
      *                 all entries with exactly this flag will be removed)
@@ -78,4 +73,4 @@ interface LocalCollection<out T: LocalResource<*>> {
      */
     fun forgetETags()
 
-}
+}

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalContact.kt

@@ -10,31 +10,26 @@ import android.provider.ContactsContract
 import android.provider.ContactsContract.CommonDataKinds.GroupMembership
 import android.provider.ContactsContract.RawContacts.Data
 import androidx.core.content.contentValuesOf
-import at.bitfire.davdroid.BuildConfig
 import at.bitfire.davdroid.resource.contactrow.CachedGroupMembershipHandler
 import at.bitfire.davdroid.resource.contactrow.GroupMembershipBuilder
 import at.bitfire.davdroid.resource.contactrow.GroupMembershipHandler
 import at.bitfire.davdroid.resource.contactrow.UnknownPropertiesBuilder
 import at.bitfire.davdroid.resource.contactrow.UnknownPropertiesHandler
+import at.bitfire.synctools.storage.BatchOperation
+import at.bitfire.synctools.storage.ContactsBatchOperation
 import at.bitfire.vcard4android.AndroidAddressBook
 import at.bitfire.vcard4android.AndroidContact
 import at.bitfire.vcard4android.AndroidContactFactory
-import at.bitfire.vcard4android.BatchOperation
 import at.bitfire.vcard4android.CachedGroupMembership
 import at.bitfire.vcard4android.Contact
-import ezvcard.Ezvcard
 import java.io.FileNotFoundException
+import java.util.Optional
 import java.util.UUID
 import kotlin.jvm.optionals.getOrNull
 
 class LocalContact: AndroidContact, LocalAddress {
 
     companion object {
-
-        init {
-            Contact.productID = "+//IDN bitfire.at//DAVx5/${BuildConfig.VERSION_NAME} ez-vcard/" + Ezvcard.VERSION
-        }
-
         const val COLUMN_FLAGS = ContactsContract.RawContacts.SYNC4
         const val COLUMN_HASHCODE = ContactsContract.RawContacts.SYNC3
     }
@@ -45,9 +40,8 @@ class LocalContact: AndroidContact, LocalAddress {
     internal val cachedGroupMemberships = HashSet<Long>()
     internal val groupMemberships = HashSet<Long>()
 
-    override var scheduleTag: String?
+    override val scheduleTag: String?
         get() = null
-        set(_) = throw NotImplementedError()
 
     override var flags: Int = 0
 
@@ -95,13 +89,13 @@ class LocalContact: AndroidContact, LocalAddress {
         _contact = null
     }
 
-    override fun clearDirty(fileName: String?, eTag: String?, scheduleTag: String?) {
+    override fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String?) {
         if (scheduleTag != null)
             throw IllegalArgumentException("Contacts must not have a Schedule-Tag")
 
         val values = ContentValues(4)
-        if (fileName != null)
-            values.put(COLUMN_FILENAME, fileName)
+        if (fileName.isPresent)
+            values.put(COLUMN_FILENAME, fileName.get())
         values.put(COLUMN_ETAG, eTag)
         values.put(ContactsContract.RawContacts.DIRTY, 0)
 
@@ -110,21 +104,25 @@ class LocalContact: AndroidContact, LocalAddress {
 
         addressBook.provider!!.update(rawContactSyncURI(), values, null, null)
 
-        if (fileName != null)
-            this.fileName = fileName
+        if (fileName.isPresent)
+            this.fileName = fileName.get()
         this.eTag = eTag
     }
 
-    override fun resetDeleted() {
-        val values = contentValuesOf(ContactsContract.Groups.DELETED to 0)
-        addressBook.provider!!.update(rawContactSyncURI(), values, null, null)
-    }
-
     fun resetDirty() {
         val values = contentValuesOf(ContactsContract.RawContacts.DIRTY to 0)
         addressBook.provider!!.update(rawContactSyncURI(), values, null, null)
     }
 
+    override fun update(data: Contact, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int) {
+        this.fileName = fileName
+        this.eTag = eTag
+        this.flags = flags
+
+        // processes this.{fileName, eTag, flags} and resets DIRTY flag
+        update(data)
+    }
+
     override fun updateFlags(flags: Int) {
         val values = contentValuesOf(COLUMN_FLAGS to flags)
         addressBook.provider!!.update(rawContactSyncURI(), values, null, null)
@@ -132,31 +130,39 @@ class LocalContact: AndroidContact, LocalAddress {
         this.flags = flags
     }
 
+    override fun deleteLocal() {
+        delete()
+    }
 
-    fun addToGroup(batch: BatchOperation, groupID: Long) {
-        batch.enqueue(BatchOperation.CpoBuilder
-                .newInsert(dataSyncURI())
-                .withValue(GroupMembership.MIMETYPE, GroupMembership.CONTENT_ITEM_TYPE)
-                .withValue(GroupMembership.RAW_CONTACT_ID, id)
-                .withValue(GroupMembership.GROUP_ROW_ID, groupID))
+    override fun resetDeleted() {
+        val values = contentValuesOf(ContactsContract.Groups.DELETED to 0)
+        addressBook.provider!!.update(rawContactSyncURI(), values, null, null)
+    }
+
+
+    fun addToGroup(batch: ContactsBatchOperation, groupID: Long) {
+        batch += BatchOperation.CpoBuilder
+            .newInsert(dataSyncURI())
+            .withValue(GroupMembership.MIMETYPE, GroupMembership.CONTENT_ITEM_TYPE)
+            .withValue(GroupMembership.RAW_CONTACT_ID, id)
+            .withValue(GroupMembership.GROUP_ROW_ID, groupID)
         groupMemberships += groupID
 
-        batch.enqueue(BatchOperation.CpoBuilder
-                .newInsert(dataSyncURI())
-                .withValue(CachedGroupMembership.MIMETYPE, CachedGroupMembership.CONTENT_ITEM_TYPE)
-                .withValue(CachedGroupMembership.RAW_CONTACT_ID, id)
-                .withValue(CachedGroupMembership.GROUP_ID, groupID)
-        )
+        batch += BatchOperation.CpoBuilder
+            .newInsert(dataSyncURI())
+            .withValue(CachedGroupMembership.MIMETYPE, CachedGroupMembership.CONTENT_ITEM_TYPE)
+            .withValue(CachedGroupMembership.RAW_CONTACT_ID, id)
+            .withValue(CachedGroupMembership.GROUP_ID, groupID)
         cachedGroupMemberships += groupID
     }
 
     fun removeGroupMemberships(batch: BatchOperation) {
-        batch.enqueue(BatchOperation.CpoBuilder
-                .newDelete(dataSyncURI())
-                .withSelection(
-                        "${Data.RAW_CONTACT_ID}=? AND ${Data.MIMETYPE} IN (?,?)",
-                        arrayOf(id.toString(), GroupMembership.CONTENT_ITEM_TYPE, CachedGroupMembership.CONTENT_ITEM_TYPE)
-                ))
+        batch += BatchOperation.CpoBuilder
+            .newDelete(dataSyncURI())
+            .withSelection(
+                "${Data.RAW_CONTACT_ID}=? AND ${Data.MIMETYPE} IN (?,?)",
+                arrayOf(id.toString(), GroupMembership.CONTENT_ITEM_TYPE, CachedGroupMembership.CONTENT_ITEM_TYPE)
+            )
         groupMemberships.clear()
         cachedGroupMemberships.clear()
     }

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalDataStore.kt

@@ -25,41 +25,44 @@ interface LocalDataStore<T: LocalCollection<*>> {
      *
      * **The caller is responsible for closing the content provider client!**
      *
-     * @return the content provider client, or `null` if the content provider could not be acquired
+     * @param throwOnMissingPermissions If `true`, the function will throw [SecurityException] if permissions are not granted.
+     *
+     * @return the content provider client, or `null` if the content provider could not be acquired (or permissions are not
+     * granted and [throwOnMissingPermissions] is `false`)
      *
      * @throws SecurityException on missing permissions
      */
-    fun acquireContentProvider(): ContentProviderClient?
+    fun acquireContentProvider(throwOnMissingPermissions: Boolean = false): ContentProviderClient?
 
     /**
      * Creates a new local collection from the given (remote) collection info.
      *
-     * @param provider       the content provider client
+     * @param client        the content provider client
      * @param fromCollection collection info
      *
      * @return the new local collection, or `null` if creation failed
      */
-    fun create(provider: ContentProviderClient, fromCollection: Collection): T?
+    fun create(client: ContentProviderClient, fromCollection: Collection): T?
 
     /**
      * Returns all local collections of the data store, including those which don't have a corresponding remote
      * [Collection] entry.
      *
      * @param account  the account that the data store is associated with
-     * @param provider the content provider client
+     * @param client   the content provider client
      *
      * @return a list of all local collections
      */
-    fun getAll(account: Account, provider: ContentProviderClient): List<T>
+    fun getAll(account: Account, client: ContentProviderClient): List<T>
 
     /**
      * Updates the local collection with the data from the given (remote) collection info.
      *
-     * @param provider        the content provider client
+     * @param client          the content provider client
      * @param localCollection the local collection to update
      * @param fromCollection  collection info
      */
-    fun update(provider: ContentProviderClient, localCollection: T, fromCollection: Collection)
+    fun update(client: ContentProviderClient, localCollection: T, fromCollection: Collection)
 
     /**
      * Deletes the local collection.

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalEvent.kt

@@ -4,195 +4,109 @@
 
 package at.bitfire.davdroid.resource
 
-import android.accounts.Account
-import android.content.ContentProviderClient
-import android.content.ContentUris
-import android.content.ContentValues
-import android.provider.CalendarContract
 import android.provider.CalendarContract.Events
 import androidx.core.content.contentValuesOf
-import at.bitfire.davdroid.BuildConfig
-import at.bitfire.davdroid.resource.LocalEvent.Companion.numInstances
-import at.bitfire.ical4android.AndroidCalendar
-import at.bitfire.ical4android.AndroidEvent
-import at.bitfire.ical4android.AndroidEventFactory
-import at.bitfire.ical4android.BatchOperation
 import at.bitfire.ical4android.Event
-import at.bitfire.ical4android.ICalendar
-import at.bitfire.ical4android.ical4jVersion
-import at.bitfire.ical4android.util.MiscUtils.asSyncAdapter
-import net.fortuna.ical4j.model.property.ProdId
+import at.bitfire.ical4android.LegacyAndroidCalendar
+import at.bitfire.synctools.mapping.calendar.LegacyAndroidEventBuilder2
+import at.bitfire.synctools.storage.LocalStorageException
+import at.bitfire.synctools.storage.calendar.AndroidEvent2
+import at.bitfire.synctools.storage.calendar.AndroidRecurringCalendar
+import java.util.Optional
 import java.util.UUID
 
-class LocalEvent: AndroidEvent, LocalResource<Event> {
+class LocalEvent(
+    val recurringCalendar: AndroidRecurringCalendar,
+    val androidEvent: AndroidEvent2
+) : LocalResource<Event> {
 
-    companion object {
-        init {
-            ICalendar.prodId = ProdId("DAVx5/${BuildConfig.VERSION_NAME} ical4j/" + ical4jVersion)
-        }
+    override val id: Long
+        get() = androidEvent.id
 
-        const val COLUMN_ETAG = Events.SYNC_DATA1
-        const val COLUMN_FLAGS = Events.SYNC_DATA2
-        const val COLUMN_SEQUENCE = Events.SYNC_DATA3
-        const val COLUMN_SCHEDULE_TAG = Events.SYNC_DATA4
+    override val fileName: String?
+        get() = androidEvent.syncId
 
-        /**
-         * Marks the event as deleted
-         * @param eventID
-         */
-        fun markAsDeleted(provider: ContentProviderClient, account: Account, eventID: Long) {
-            provider.update(
-                ContentUris.withAppendedId(
-                    Events.CONTENT_URI,
-                    eventID
-                ).asSyncAdapter(account),
-                contentValuesOf(Events.DELETED to 1),
-                null, null
-            )
-        }
+    override val eTag: String?
+        get() = androidEvent.eTag
+
+    override val scheduleTag: String?
+        get() = androidEvent.scheduleTag
+
+    override val flags: Int
+        get() = androidEvent.flags
 
 
-        /**
-         * Finds the amount of direct instances this event has (without exceptions); used by [numInstances]
-         * to find the number of instances of exceptions.
-         *
-         * The number of returned instances may vary with the Android version.
-         *
-         * @return number of direct event instances (not counting instances of exceptions); *null* if
-         * the number can't be determined or if the event has no last date (recurring event without last instance)
-         */
-        fun numDirectInstances(provider: ContentProviderClient, account: Account, eventID: Long): Int? {
-            // query event to get first and last instance
-            var first: Long? = null
-            var last: Long? = null
-            provider.query(
-                ContentUris.withAppendedId(
-                    Events.CONTENT_URI,
-                    eventID
-                ),
-                arrayOf(Events.DTSTART, Events.LAST_DATE), null, null, null
-            )?.use { cursor ->
-                cursor.moveToNext()
-                if (!cursor.isNull(0))
-                    first = cursor.getLong(0)
-                if (!cursor.isNull(1))
-                    last = cursor.getLong(1)
-            }
-            // if this event doesn't have a last occurence, it's endless and always has instances
-            if (first == null || last == null)
-                return null
-
-            /* We can't use Long.MIN_VALUE and Long.MAX_VALUE because Android generates the instances
-             on the fly and it doesn't accept those values. So we use the first/last actual occurence
-             of the event (calculated by Android). */
-            val instancesUri = CalendarContract.Instances.CONTENT_URI.asSyncAdapter(account)
-                .buildUpon()
-                .appendPath(first.toString())       // begin timestamp
-                .appendPath(last.toString())        // end timestamp
-                .build()
-
-            var numInstances = 0
-            provider.query(
-                instancesUri, null,
-                "${CalendarContract.Instances.EVENT_ID}=?", arrayOf(eventID.toString()),
-                null
-            )?.use { cursor ->
-                numInstances += cursor.count
-            }
-            return numInstances
-        }
-
-        /**
-         * Finds the total number of instances this event has (including instances of exceptions)
-         *
-         * The number of returned instances may vary with the Android version.
-         *
-         * @return number of direct event instances (not counting instances of exceptions); *null* if
-         * the number can't be determined or if the event has no last date (recurring event without last instance)
-         */
-        fun numInstances(provider: ContentProviderClient, account: Account, eventID: Long): Int? {
-            // num instances of the main event
-            var numInstances = numDirectInstances(provider, account, eventID) ?: return null
-
-            // add the number of instances of every main event's exception
-            provider.query(
-                Events.CONTENT_URI,
-                arrayOf(Events._ID),
-                "${Events.ORIGINAL_ID}=?", // get exception events of the main event
-                arrayOf("$eventID"), null
-            )?.use { exceptionsEventCursor ->
-                while (exceptionsEventCursor.moveToNext()) {
-                    val exceptionEventID = exceptionsEventCursor.getLong(0)
-                    val exceptionInstances = numDirectInstances(provider, account, exceptionEventID)
-
-                    if (exceptionInstances == null)
-                        // number of instances of exception can't be determined; so the total number of instances is also unclear
-                        return null
-
-                    numInstances += exceptionInstances
-                }
-            }
-            return numInstances
-        }
-
+    override fun update(data: Event, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int) {
+        val eventAndExceptions = LegacyAndroidEventBuilder2(
+            calendar = androidEvent.calendar,
+            event = data,
+            id = id,
+            syncId = fileName,
+            eTag = eTag,
+            scheduleTag = scheduleTag,
+            flags = flags
+        ).build()
+        recurringCalendar.updateEventAndExceptions(id, eventAndExceptions)
     }
 
-    override var fileName: String? = null
-        private set
 
-    override var eTag: String? = null
-    override var scheduleTag: String? = null
+    private var _event: Event? = null
+    /**
+     * Retrieves the event from the content provider and converts it to a legacy data object.
+     *
+     * Caches the result: the content provider is only queried at the first call and then
+     * this method always returns the same object.
+     *
+     * @throws LocalStorageException    if there is no local event with the ID from [androidEvent]
+     */
+    @Synchronized
+    fun getCachedEvent(): Event {
+        _event?.let { return it }
 
-    override var flags: Int = 0
-        private set
+        val legacyCalendar = LegacyAndroidCalendar(androidEvent.calendar)
+        val event = legacyCalendar.getEvent(androidEvent.id)
+            ?: throw LocalStorageException("Event ${androidEvent.id} not found")
 
-    var weAreOrganizer = false
-        private set
-
-
-    constructor(calendar: AndroidCalendar<*>, event: Event, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int): super(calendar, event) {
-        this.fileName = fileName
-        this.eTag = eTag
-        this.scheduleTag = scheduleTag
-        this.flags = flags
+        _event = event
+        return event
     }
 
-    private constructor(calendar: AndroidCalendar<*>, values: ContentValues): super(calendar, values) {
-        fileName = values.getAsString(Events._SYNC_ID)
-        eTag = values.getAsString(COLUMN_ETAG)
-        scheduleTag = values.getAsString(COLUMN_SCHEDULE_TAG)
-        flags = values.getAsInteger(COLUMN_FLAGS) ?: 0
+    /**
+     * Generates the [Event] that should actually be uploaded:
+     *
+     * 1. Takes the [getCachedEvent].
+     * 2. Calculates the new SEQUENCE.
+     *
+     * _Note: This method currently modifies the object returned by [getCachedEvent], but
+     * this may change in the future._
+     *
+     * @return data object that should be used for uploading
+     */
+    fun eventToUpload(): Event {
+        val event = getCachedEvent()
+
+        val nonGroupScheduled = event.attendees.isEmpty()
+        val weAreOrganizer = event.isOrganizer == true
+
+        // Increase sequence (event.sequence null/non-null behavior is defined by the Event, see KDoc of event.sequence):
+        // - If it's null, the event has just been created in the database, so we can start with SEQUENCE:0 (default).
+        // - If it's non-null, the event already exists on the server, so increase by one.
+        val sequence = event.sequence
+        if (sequence != null && (nonGroupScheduled || weAreOrganizer))
+            event.sequence = sequence + 1
+
+        return event
     }
 
-    override fun populateEvent(row: ContentValues, groupScheduled: Boolean) {
-        val event = requireNotNull(event)
-        event.sequence = row.getAsInteger(COLUMN_SEQUENCE)
-
-        val isOrganizer = row.getAsInteger(Events.IS_ORGANIZER)
-        weAreOrganizer = isOrganizer != null && isOrganizer != 0
-
-        super.populateEvent(row, groupScheduled)
-    }
-
-    override fun buildEvent(recurrence: Event?, builder: BatchOperation.CpoBuilder) {
-        val event = requireNotNull(event)
-
-        val buildException = recurrence != null
-        val eventToBuild = recurrence ?: event
-
-        builder .withValue(COLUMN_SEQUENCE, eventToBuild.sequence)
-                .withValue(Events.DIRTY, 0)
-                .withValue(Events.DELETED, 0)
-                .withValue(COLUMN_FLAGS, flags)
-
-        if (buildException)
-            builder .withValue(Events.ORIGINAL_SYNC_ID, fileName)
-        else
-            builder .withValue(Events._SYNC_ID, fileName)
-                    .withValue(COLUMN_ETAG, eTag)
-                    .withValue(COLUMN_SCHEDULE_TAG, scheduleTag)
-
-        super.buildEvent(recurrence, builder)
+    /**
+     * Updates the SEQUENCE of the event in the content provider.
+     *
+     * @param sequence  new sequence value
+     */
+    fun updateSequence(sequence: Int?) {
+        androidEvent.update(contentValuesOf(
+            AndroidEvent2.COLUMN_SEQUENCE to sequence
+        ))
     }
 
 
@@ -204,25 +118,25 @@ class LocalEvent: AndroidEvent, LocalResource<Event> {
      */
     override fun prepareForUpload(): String {
         // make sure that UID is set
-        val uid: String = event!!.uid ?: run {
+        val uid: String = getCachedEvent().uid ?: run {
             // generate new UID
             val newUid = UUID.randomUUID().toString()
 
-            // update in calendar provider
+            // persist to calendar provider
             val values = contentValuesOf(Events.UID_2445 to newUid)
-            calendar.provider.update(eventSyncURI(), values, null, null)
+            androidEvent.update(values)
 
-            // update this event
-            event?.uid = newUid
+            // update in cached event data object
+            getCachedEvent().uid = newUid
 
             newUid
         }
 
         val uidIsGoodFilename = uid.all { char ->
             // see RFC 2396 2.2
-            char.isLetterOrDigit() || arrayOf(          // allow letters and digits
-                ';',':','@','&','=','+','$',',',        // allow reserved characters except '/' and '?'
-                '-','_','.','!','~','*','\'','(',')'    // allow unreserved characters
+            char.isLetterOrDigit() || arrayOf(                  // allow letters and digits
+                ';', ':', '@', '&', '=', '+', '$', ',',         // allow reserved characters except '/' and '?'
+                '-', '_', '.', '!', '~', '*', '\'', '(', ')'    // allow unreserved characters
             ).contains(char)
         }
         return if (uidIsGoodFilename)
@@ -231,39 +145,31 @@ class LocalEvent: AndroidEvent, LocalResource<Event> {
             "${UUID.randomUUID()}.ics"      // UID would be dangerous as file name, use random UUID instead
     }
 
-
-    override fun clearDirty(fileName: String?, eTag: String?, scheduleTag: String?) {
-        val values = ContentValues(5)
-        if (fileName != null)
-            values.put(Events._SYNC_ID, fileName)
-        values.put(COLUMN_ETAG, eTag)
-        values.put(COLUMN_SCHEDULE_TAG, scheduleTag)
-        values.put(COLUMN_SEQUENCE, event!!.sequence)
-        values.put(Events.DIRTY, 0)
-        calendar.provider.update(eventSyncURI(), values, null, null)
-
-        if (fileName != null)
-            this.fileName = fileName
-        this.eTag = eTag
-        this.scheduleTag = scheduleTag
+    override fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String?) {
+        val values = contentValuesOf(
+            Events.DIRTY to 0,
+            AndroidEvent2.COLUMN_ETAG to eTag,
+            AndroidEvent2.COLUMN_SCHEDULE_TAG to scheduleTag
+        )
+        if (fileName.isPresent)
+            values.put(Events._SYNC_ID, fileName.get())
+        androidEvent.update(values)
     }
 
     override fun updateFlags(flags: Int) {
-        val values = contentValuesOf(COLUMN_FLAGS to flags)
-        calendar.provider.update(eventSyncURI(), values, null, null)
+        androidEvent.update(contentValuesOf(
+            AndroidEvent2.COLUMN_FLAGS to flags
+        ))
+    }
 
-        this.flags = flags
+    override fun deleteLocal() {
+        recurringCalendar.deleteEventAndExceptions(id)
     }
 
     override fun resetDeleted() {
-        val values = contentValuesOf(Events.DELETED to 0)
-        calendar.provider.update(eventSyncURI(), values, null, null)
+        androidEvent.update(contentValuesOf(
+            Events.DELETED to 0
+        ))
     }
 
-    object Factory: AndroidEventFactory<LocalEvent> {
-        override fun fromProvider(calendar: AndroidCalendar<*>, values: ContentValues) =
-                LocalEvent(calendar, values)
-    }
-
-}
-
+}

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalGroup.kt

@@ -14,15 +14,18 @@ import android.provider.ContactsContract.Groups
 import android.provider.ContactsContract.RawContacts
 import android.provider.ContactsContract.RawContacts.Data
 import androidx.core.content.contentValuesOf
+import at.bitfire.davdroid.resource.LocalGroup.Companion.COLUMN_PENDING_MEMBERS
 import at.bitfire.davdroid.util.trimToNull
+import at.bitfire.synctools.storage.BatchOperation
+import at.bitfire.synctools.storage.ContactsBatchOperation
 import at.bitfire.vcard4android.AndroidAddressBook
 import at.bitfire.vcard4android.AndroidContact
 import at.bitfire.vcard4android.AndroidGroup
 import at.bitfire.vcard4android.AndroidGroupFactory
-import at.bitfire.vcard4android.BatchOperation
 import at.bitfire.vcard4android.CachedGroupMembership
 import at.bitfire.vcard4android.Contact
 import java.util.LinkedList
+import java.util.Optional
 import java.util.UUID
 import java.util.logging.Logger
 import kotlin.jvm.optionals.getOrNull
@@ -53,7 +56,7 @@ class LocalGroup: AndroidGroup, LocalAddress {
             addressBook.allGroups { group ->
                 val groupId = group.id!!
                 val pendingMemberUids = group.pendingMemberships.toMutableSet()
-                val batch = BatchOperation(addressBook.provider!!)
+                val batch = ContactsBatchOperation(addressBook.provider!!)
 
                 // required for workaround for Android 7 which sets DIRTY flag when only meta-data is changed
                 val changeContactIDs = HashSet<Long>()
@@ -109,7 +112,7 @@ class LocalGroup: AndroidGroup, LocalAddress {
 
     override var scheduleTag: String?
         get() = null
-        set(value) = throw NotImplementedError()
+        set(_) = throw NotImplementedError()
 
     override var flags: Int = 0
 
@@ -157,40 +160,40 @@ class LocalGroup: AndroidGroup, LocalAddress {
         return "$uid.vcf"
     }
 
-    override fun clearDirty(fileName: String?, eTag: String?, scheduleTag: String?) {
+    override fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String?) {
         if (scheduleTag != null)
             throw IllegalArgumentException("Contact groups must not have a Schedule-Tag")
         val id = requireNotNull(id)
 
         val values = ContentValues(3)
-        if (fileName != null)
-            values.put(COLUMN_FILENAME, fileName)
+        if (fileName.isPresent)
+            values.put(COLUMN_FILENAME, fileName.get())
         values.putNull(COLUMN_ETAG)     // don't save changed ETag but null, so that the group is downloaded again, so that pendingMembers is updated
         values.put(Groups.DIRTY, 0)
         update(values)
 
-        if (fileName != null)
-            this.fileName = fileName
+        if (fileName.isPresent)
+            this.fileName = fileName.get()
         this.eTag = null
 
         // update cached group memberships
-        val batch = BatchOperation(addressBook.provider!!)
+        val batch = ContactsBatchOperation(addressBook.provider!!)
 
         // delete old cached group memberships
-        batch.enqueue(BatchOperation.CpoBuilder
-                .newDelete(addressBook.syncAdapterURI(ContactsContract.Data.CONTENT_URI))
-                .withSelection(
-                        CachedGroupMembership.MIMETYPE + "=? AND " + CachedGroupMembership.GROUP_ID + "=?",
-                        arrayOf(CachedGroupMembership.CONTENT_ITEM_TYPE, id.toString())
-                ))
+        batch += BatchOperation.CpoBuilder
+            .newDelete(addressBook.syncAdapterURI(ContactsContract.Data.CONTENT_URI))
+            .withSelection(
+                CachedGroupMembership.MIMETYPE + "=? AND " + CachedGroupMembership.GROUP_ID + "=?",
+                arrayOf(CachedGroupMembership.CONTENT_ITEM_TYPE, id.toString())
+            )
 
         // insert updated cached group memberships
         for (member in getMembers())
-            batch.enqueue(BatchOperation.CpoBuilder
-                    .newInsert(addressBook.syncAdapterURI(ContactsContract.Data.CONTENT_URI))
-                    .withValue(CachedGroupMembership.MIMETYPE, CachedGroupMembership.CONTENT_ITEM_TYPE)
-                    .withValue(CachedGroupMembership.RAW_CONTACT_ID, member)
-                    .withValue(CachedGroupMembership.GROUP_ID, id))
+            batch += BatchOperation.CpoBuilder
+                .newInsert(addressBook.syncAdapterURI(ContactsContract.Data.CONTENT_URI))
+                .withValue(CachedGroupMembership.MIMETYPE, CachedGroupMembership.CONTENT_ITEM_TYPE)
+                .withValue(CachedGroupMembership.RAW_CONTACT_ID, member)
+                .withValue(CachedGroupMembership.GROUP_ID, id)
 
         batch.commit()
     }
@@ -199,19 +202,23 @@ class LocalGroup: AndroidGroup, LocalAddress {
      * Marks all members of the current group as dirty.
      */
     fun markMembersDirty() {
-        val batch = BatchOperation(addressBook.provider!!)
+        val batch = ContactsBatchOperation(addressBook.provider!!)
 
         for (member in getMembers())
-            batch.enqueue(BatchOperation.CpoBuilder
-                    .newUpdate(addressBook.syncAdapterURI(ContentUris.withAppendedId(RawContacts.CONTENT_URI, member)))
-                    .withValue(RawContacts.DIRTY, 1))
+            batch += BatchOperation.CpoBuilder
+                .newUpdate(addressBook.syncAdapterURI(ContentUris.withAppendedId(RawContacts.CONTENT_URI, member)))
+                .withValue(RawContacts.DIRTY, 1)
 
         batch.commit()
     }
 
-    override fun resetDeleted() {
-        val values = contentValuesOf(Groups.DELETED to 0)
-        addressBook.provider!!.update(groupSyncUri(), values, null, null)
+    override fun update(data: Contact, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int) {
+        this.fileName = fileName
+        this.eTag = eTag
+        this.scheduleTag = scheduleTag
+
+        // processes this.{fileName, eTag, flags} and resets DIRTY flag
+        update(data)
     }
 
     override fun updateFlags(flags: Int) {
@@ -221,6 +228,15 @@ class LocalGroup: AndroidGroup, LocalAddress {
         this.flags = flags
     }
 
+    override fun deleteLocal() {
+        delete()
+    }
+
+    override fun resetDeleted() {
+        val values = contentValuesOf(Groups.DELETED to 0)
+        addressBook.provider!!.update(groupSyncUri(), values, null, null)
+    }
+
 
     // helpers
 

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalJtxCollection.kt

@@ -6,7 +6,6 @@ package at.bitfire.davdroid.resource
 
 import android.accounts.Account
 import android.content.ContentProviderClient
-import at.bitfire.davdroid.db.SyncState
 import at.bitfire.ical4android.JtxCollection
 import at.bitfire.ical4android.JtxCollectionFactory
 import at.bitfire.ical4android.JtxICalObject

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalJtxCollectionStore.kt

@@ -37,8 +37,14 @@ class LocalJtxCollectionStore @Inject constructor(
     override val authority: String
         get() = JtxContract.AUTHORITY
 
-    override fun acquireContentProvider() =
-        context.contentResolver.acquireContentProviderClient(JtxContract.AUTHORITY)
+    override fun acquireContentProvider(throwOnMissingPermissions: Boolean) = try {
+        context.contentResolver.acquireContentProviderClient(authority)
+    } catch (e: SecurityException) {
+        if (throwOnMissingPermissions)
+            throw e
+        else
+            /* return */ null
+    }
 
     override fun create(provider: ContentProviderClient, fromCollection: Collection): LocalJtxCollection? {
         val service = serviceDao.get(fromCollection.serviceId) ?: throw IllegalArgumentException("Couldn't fetch DB service from collection")

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalJtxICalObject.kt

@@ -9,6 +9,8 @@ import at.bitfire.ical4android.JtxCollection
 import at.bitfire.ical4android.JtxICalObject
 import at.bitfire.ical4android.JtxICalObjectFactory
 import at.techbee.jtx.JtxContract
+import java.util.Optional
+import kotlin.jvm.optionals.getOrNull
 
 class LocalJtxICalObject(
     collection: JtxCollection<*>,
@@ -48,6 +50,24 @@ class LocalJtxICalObject(
 
     }
 
+    override fun update(data: JtxICalObject, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int) {
+        this.fileName = fileName
+        this.eTag = eTag
+        this.scheduleTag = scheduleTag
+        this.flags = flags
+
+        // processes this.{fileName, eTag, scheduleTag, flags} and resets DIRTY flag
+        update(data)
+    }
+
+    override fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String?) {
+        clearDirty(fileName.getOrNull(), eTag, scheduleTag)
+    }
+
+    override fun deleteLocal() {
+        delete()
+    }
+
     override fun resetDeleted() {
         throw NotImplementedError()
     }

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalResource.kt

@@ -4,8 +4,12 @@
 
 package at.bitfire.davdroid.resource
 
-import android.net.Uri
+import at.bitfire.davdroid.resource.LocalResource.Companion.FLAG_REMOTELY_PRESENT
+import java.util.Optional
 
+/**
+ * Defines operations that are used by SyncManager for all sync data types.
+ */
 interface LocalResource<in TData: Any> {
 
     companion object {
@@ -32,10 +36,10 @@ interface LocalResource<in TData: Any> {
     val fileName: String?
 
     /** remote ETag for the resource */
-    var eTag: String?
+    val eTag: String?
 
     /** remote Schedule-Tag for the resource */
-    var scheduleTag: String?
+    val scheduleTag: String?
 
     /** bitfield of flags; currently either [FLAG_REMOTELY_PRESENT] or 0 */
     val flags: Int
@@ -48,47 +52,41 @@ interface LocalResource<in TData: Any> {
      *   saved to the content provider. The sync manager is responsible for saving the file name that
      *   was actually used.
      *
-     * @return new file name of the resource (like "<uid>.vcf")
+     * @return suggestion for new file name of the resource (like "<uid>.vcf")
      */
     fun prepareForUpload(): String
 
     /**
-     * Unsets the /dirty/ field of the resource. Typically used after successfully uploading a
-     * locally modified resource.
+     * Unsets the _dirty_ field of the resource and updates other sync-related fields in the content provider.
+     * Does not affect `this` object itself (which is immutable).
      *
-     * @param fileName If this argument is not *null*, [LocalResource.fileName] will be set to its value.
-     * @param eTag ETag of the uploaded resource as returned by the server (null if the server didn't return one)
-     * @param scheduleTag CalDAV Schedule-Tag of the uploaded resource as returned by the server (null if not applicable or if the server didn't return one)
+     * @param fileName      If this optional argument is present, [LocalResource.fileName] will be set to its value.
+     * @param eTag          ETag of the uploaded resource as returned by the server (null if the server didn't return one)
+     * @param scheduleTag   CalDAV only: `Schedule-Tag` of the uploaded resource as returned by the server
+     *                      (null if not applicable or if the server didn't return one)
      */
-    fun clearDirty(fileName: String?, eTag: String?, scheduleTag: String? = null)
+    fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String? = null)
 
     /**
-     * Sets (local) flags of the resource. At the moment, the only allowed values are
-     * 0 and [FLAG_REMOTELY_PRESENT].
+     * Sets (local) flags of the resource in the content provider.
+     * Does not affect `this` object itself (which is immutable).
+     *
+     * At the moment, the only allowed values are 0 and [FLAG_REMOTELY_PRESENT].
      */
     fun updateFlags(flags: Int)
 
-
-    /**
-     * Adds the data object to the content provider and ensures that the dirty flag is clear.
-     *
-     * @return content URI of the created row (e.g. event URI)
-     */
-    fun add(): Uri
-
     /**
      * Updates the data object in the content provider and ensures that the dirty flag is clear.
+     * Does not affect `this` or the [data] object (which are both immutable).
      *
      * @return content URI of the updated row (e.g. event URI)
      */
-    fun update(data: TData): Uri
+    fun update(data: TData, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int)
 
     /**
      * Deletes the data object from the content provider.
-     *
-     * @return number of affected rows
      */
-    fun delete(): Int
+    fun deleteLocal()
 
     /**
      * Undoes deletion of the data object from the content provider.

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalTask.kt

@@ -6,12 +6,13 @@ package at.bitfire.davdroid.resource
 
 import android.content.ContentValues
 import androidx.core.content.contentValuesOf
-import at.bitfire.ical4android.BatchOperation
 import at.bitfire.ical4android.DmfsTask
 import at.bitfire.ical4android.DmfsTaskFactory
 import at.bitfire.ical4android.DmfsTaskList
 import at.bitfire.ical4android.Task
+import at.bitfire.synctools.storage.BatchOperation
 import org.dmfs.tasks.contract.TaskContract.Tasks
+import java.util.Optional
 import java.util.UUID
 
 class LocalTask: DmfsTask, LocalResource<Task> {
@@ -76,23 +77,33 @@ class LocalTask: DmfsTask, LocalResource<Task> {
         return "$uid.ics"
     }
 
-    override fun clearDirty(fileName: String?, eTag: String?, scheduleTag: String?) {
+    override fun clearDirty(fileName: Optional<String>, eTag: String?, scheduleTag: String?) {
         if (scheduleTag != null)
             logger.fine("Schedule-Tag for tasks not supported yet, won't save")
 
         val values = ContentValues(4)
-        if (fileName != null)
-            values.put(Tasks._SYNC_ID, fileName)
+        if (fileName.isPresent)
+            values.put(Tasks._SYNC_ID, fileName.get())
         values.put(COLUMN_ETAG, eTag)
         values.put(Tasks.SYNC_VERSION, task!!.sequence)
         values.put(Tasks._DIRTY, 0)
         taskList.provider.update(taskSyncURI(), values, null, null)
 
-        if (fileName != null)
-            this.fileName = fileName
+        if (fileName.isPresent)
+            this.fileName = fileName.get()
         this.eTag = eTag
     }
 
+    override fun update(data: Task, fileName: String?, eTag: String?, scheduleTag: String?, flags: Int) {
+        this.fileName = fileName
+        this.eTag = eTag
+        this.scheduleTag = scheduleTag
+        this.flags = flags
+
+        // processes this.{fileName, eTag, scheduleTag, flags} and resets DIRTY flag
+        update(data)
+    }
+
     override fun updateFlags(flags: Int) {
         if (id != null) {
             val values = contentValuesOf(COLUMN_FLAGS to flags)
@@ -102,6 +113,10 @@ class LocalTask: DmfsTask, LocalResource<Task> {
         this.flags = flags
     }
 
+    override fun deleteLocal() {
+        delete()
+    }
+
     override fun resetDeleted() {
         throw NotImplementedError()
     }
@@ -111,4 +126,4 @@ class LocalTask: DmfsTask, LocalResource<Task> {
         override fun fromProvider(taskList: DmfsTaskList<*>, values: ContentValues) =
                 LocalTask(taskList, values)
     }
-}
+}

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalTaskList.kt

@@ -8,7 +8,6 @@ import android.accounts.Account
 import android.content.ContentProviderClient
 import android.content.ContentValues
 import androidx.core.content.contentValuesOf
-import at.bitfire.davdroid.db.SyncState
 import at.bitfire.ical4android.DmfsTaskList
 import at.bitfire.ical4android.DmfsTaskListFactory
 import at.bitfire.ical4android.TaskProvider
@@ -110,7 +109,7 @@ class LocalTaskList private constructor(
                     arrayOf(id.toString(), flags.toString()))
 
     override fun forgetETags() {
-        val values = contentValuesOf(LocalEvent.COLUMN_ETAG to null)
+        val values = contentValuesOf(LocalTask.COLUMN_ETAG to null)
         provider.update(tasksSyncUri(), values, "${Tasks.LIST_ID}=?",
                 arrayOf(id.toString()))
     }

app/src/main/kotlin/at/bitfire/davdroid/resource/LocalTaskListStore.kt

@@ -47,8 +47,14 @@ class LocalTaskListStore @AssistedInject constructor(
     override val authority: String
         get() = providerName.authority
 
-    override fun acquireContentProvider() =
+    override fun acquireContentProvider(throwOnMissingPermissions: Boolean) = try {
         context.contentResolver.acquireContentProviderClient(authority)
+    } catch (e: SecurityException) {
+        if (throwOnMissingPermissions)
+            throw e
+        else
+            /* return */ null
+    }
 
     override fun create(provider: ContentProviderClient, fromCollection: Collection): LocalTaskList? {
         val service = serviceDao.get(fromCollection.serviceId) ?: throw IllegalArgumentException("Couldn't fetch DB service from collection")

app/src/main/kotlin/at/bitfire/davdroid/resource/SyncState.kt

@@ -2,21 +2,21 @@
  * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
  */
 
-package at.bitfire.davdroid.db
+package at.bitfire.davdroid.resource
 
 import at.bitfire.dav4jvm.property.webdav.SyncToken
 import org.json.JSONException
 import org.json.JSONObject
 
 data class SyncState(
-        val type: Type,
-        val value: String,
+    val type: Type,
+    val value: String,
 
-        /**
-         * Whether this sync state occurred during an initial sync as described
-         * in RFC 6578, which means the initial sync is not complete yet.
-         */
-        var initialSync: Boolean? = null
+    /**
+     * Whether this sync state occurred during an initial sync as described
+     * in RFC 6578, which means the initial sync is not complete yet.
+     */
+    var initialSync: Boolean? = null
 ) {
 
     companion object {

app/src/main/kotlin/at/bitfire/davdroid/resource/contactrow/GroupMembershipBuilder.kt

@@ -7,7 +7,7 @@ package at.bitfire.davdroid.resource.contactrow
 import android.net.Uri
 import android.provider.ContactsContract.CommonDataKinds.GroupMembership
 import at.bitfire.davdroid.resource.LocalAddressBook
-import at.bitfire.vcard4android.BatchOperation
+import at.bitfire.synctools.storage.BatchOperation
 import at.bitfire.vcard4android.Contact
 import at.bitfire.vcard4android.GroupMethod
 import at.bitfire.vcard4android.contactrow.DataRowBuilder

app/src/main/kotlin/at/bitfire/davdroid/resource/contactrow/UnknownPropertiesBuilder.kt

@@ -5,7 +5,7 @@
 package at.bitfire.davdroid.resource.contactrow
 
 import android.net.Uri
-import at.bitfire.vcard4android.BatchOperation
+import at.bitfire.synctools.storage.BatchOperation
 import at.bitfire.vcard4android.Contact
 import at.bitfire.vcard4android.contactrow.DataRowBuilder
 import java.util.LinkedList

app/src/main/kotlin/at/bitfire/davdroid/resource/workaround/Android7DirtyVerifier.kt

@@ -9,7 +9,8 @@ import android.os.Build
 import at.bitfire.davdroid.resource.LocalAddressBook
 import at.bitfire.davdroid.resource.LocalContact
 import at.bitfire.davdroid.resource.LocalContact.Companion.COLUMN_HASHCODE
-import at.bitfire.vcard4android.BatchOperation
+import at.bitfire.synctools.storage.BatchOperation
+import at.bitfire.synctools.storage.ContactsBatchOperation
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
@@ -129,12 +130,12 @@ class Android7DirtyVerifier @Inject constructor(
         addressBook.provider!!.update(contact.rawContactSyncURI(), values, null, null)
     }
 
-    override fun updateHashCode(contact: LocalContact, batch: BatchOperation) {
+    override fun updateHashCode(contact: LocalContact, batch: ContactsBatchOperation) {
         val hashCode = contactDataHashCode(contact)
 
-        batch.enqueue(BatchOperation.CpoBuilder
+        batch += BatchOperation.CpoBuilder
             .newUpdate(contact.rawContactSyncURI())
-            .withValue(COLUMN_HASHCODE, hashCode))
+            .withValue(COLUMN_HASHCODE, hashCode)
     }
 
 

app/src/main/kotlin/at/bitfire/davdroid/resource/workaround/ContactDirtyVerifier.kt

@@ -7,7 +7,7 @@ package at.bitfire.davdroid.resource.workaround
 import android.content.ContentValues
 import at.bitfire.davdroid.resource.LocalAddressBook
 import at.bitfire.davdroid.resource.LocalContact
-import at.bitfire.vcard4android.BatchOperation
+import at.bitfire.synctools.storage.ContactsBatchOperation
 
 /**
  * Only required for [Android7DirtyVerifier]. If that class is removed because the minimum SDK is raised to Android 8,
@@ -49,6 +49,6 @@ interface ContactDirtyVerifier {
     /**
       Sets the [LocalContact.COLUMN_HASHCODE] field of the contact to the hash code of the contact data in a content provider batch operation.
      */
-    fun updateHashCode(contact: LocalContact, batch: BatchOperation)
+    fun updateHashCode(contact: LocalContact, batch: ContactsBatchOperation)
 
 }

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/CollectionListRefresher.kt

@@ -1,421 +0,0 @@
-/*
- * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
- */
-
-package at.bitfire.davdroid.servicedetection
-
-import at.bitfire.dav4jvm.DavResource
-import at.bitfire.dav4jvm.Property
-import at.bitfire.dav4jvm.Response
-import at.bitfire.dav4jvm.UrlUtils
-import at.bitfire.dav4jvm.exception.HttpException
-import at.bitfire.dav4jvm.property.caldav.CalendarColor
-import at.bitfire.dav4jvm.property.caldav.CalendarDescription
-import at.bitfire.dav4jvm.property.caldav.CalendarHomeSet
-import at.bitfire.dav4jvm.property.caldav.CalendarProxyReadFor
-import at.bitfire.dav4jvm.property.caldav.CalendarProxyWriteFor
-import at.bitfire.dav4jvm.property.caldav.CalendarTimezone
-import at.bitfire.dav4jvm.property.caldav.CalendarTimezoneId
-import at.bitfire.dav4jvm.property.caldav.Source
-import at.bitfire.dav4jvm.property.caldav.SupportedCalendarComponentSet
-import at.bitfire.dav4jvm.property.carddav.AddressbookDescription
-import at.bitfire.dav4jvm.property.carddav.AddressbookHomeSet
-import at.bitfire.dav4jvm.property.push.PushTransports
-import at.bitfire.dav4jvm.property.push.Topic
-import at.bitfire.dav4jvm.property.webdav.CurrentUserPrivilegeSet
-import at.bitfire.dav4jvm.property.webdav.DisplayName
-import at.bitfire.dav4jvm.property.webdav.GroupMembership
-import at.bitfire.dav4jvm.property.webdav.HrefListProperty
-import at.bitfire.dav4jvm.property.webdav.Owner
-import at.bitfire.dav4jvm.property.webdav.ResourceType
-import at.bitfire.davdroid.db.AppDatabase
-import at.bitfire.davdroid.db.Collection
-import at.bitfire.davdroid.db.HomeSet
-import at.bitfire.davdroid.db.Principal
-import at.bitfire.davdroid.db.Service
-import at.bitfire.davdroid.repository.DavCollectionRepository
-import at.bitfire.davdroid.repository.DavHomeSetRepository
-import at.bitfire.davdroid.settings.Settings
-import at.bitfire.davdroid.settings.SettingsManager
-import at.bitfire.davdroid.util.DavUtils.parent
-import dagger.assisted.Assisted
-import dagger.assisted.AssistedFactory
-import dagger.assisted.AssistedInject
-import okhttp3.HttpUrl
-import okhttp3.OkHttpClient
-import java.util.logging.Level
-import java.util.logging.Logger
-
-/**
- * Logic for refreshing the list of collections and home-sets and related information.
- */
-class CollectionListRefresher @AssistedInject constructor(
-    @Assisted private val service: Service,
-    @Assisted private val httpClient: OkHttpClient,
-    private val db: AppDatabase,
-    private val collectionRepository: DavCollectionRepository,
-    private val homeSetRepository: DavHomeSetRepository,
-    private val logger: Logger,
-    private val settings: SettingsManager
-) {
-
-    @AssistedFactory
-    interface Factory {
-        fun create(service: Service, httpClient: OkHttpClient): CollectionListRefresher
-    }
-
-    /**
-     * Principal properties to ask the server for.
-     */
-    private val principalProperties = arrayOf(
-        DisplayName.NAME,
-        ResourceType.NAME
-    )
-
-    /**
-     * Home-set class to use depending on the given service type.
-     */
-    private val homeSetClass: Class<out HrefListProperty> =
-        when (service.type) {
-            Service.TYPE_CARDDAV -> AddressbookHomeSet::class.java
-            Service.TYPE_CALDAV -> CalendarHomeSet::class.java
-            else -> throw IllegalArgumentException()
-        }
-
-    /**
-     * Home-set properties to ask for in a PROPFIND request to the principal URL,
-     * depending on the given service type.
-     */
-    private val homeSetProperties: Array<Property.Name> =
-        arrayOf(                        // generic WebDAV properties
-            DisplayName.NAME,
-            GroupMembership.NAME,
-            ResourceType.NAME
-        ) + when (service.type) {       // service-specific CalDAV/CardDAV properties
-                Service.TYPE_CARDDAV -> arrayOf(
-                    AddressbookHomeSet.NAME,
-                )
-                Service.TYPE_CALDAV -> arrayOf(
-                    CalendarHomeSet.NAME,
-                    CalendarProxyReadFor.NAME,
-                    CalendarProxyWriteFor.NAME
-                )
-                else -> throw IllegalArgumentException()
-            }
-
-    /**
-     * Collection properties to ask for in a PROPFIND request on a collection.
-     */
-    private val collectionProperties: Array<Property.Name> =
-        arrayOf(                        // generic WebDAV properties
-            CurrentUserPrivilegeSet.NAME,
-            DisplayName.NAME,
-            Owner.NAME,
-            ResourceType.NAME,
-            PushTransports.NAME,        // WebDAV-Push
-            Topic.NAME
-        ) + when (service.type) {       // service-specific CalDAV/CardDAV properties
-            Service.TYPE_CARDDAV -> arrayOf(
-                AddressbookDescription.NAME
-            )
-            Service.TYPE_CALDAV -> arrayOf(
-                CalendarColor.NAME,
-                CalendarDescription.NAME,
-                CalendarTimezone.NAME,
-                CalendarTimezoneId.NAME,
-                SupportedCalendarComponentSet.NAME,
-                Source.NAME
-            )
-            else -> throw IllegalArgumentException()
-        }
-
-
-
-    /**
-     * Starting at given principal URL, tries to recursively find and save all user relevant home sets.
-     *
-     * @param principalUrl              URL of principal to query (user-provided principal or current-user-principal)
-     * @param level                     Current recursion level (limited to 0, 1 or 2):
-     *   - 0: We assume found home sets belong to the current-user-principal
-     *   - 1 or 2: We assume found home sets don't directly belong to the current-user-principal
-     * @param alreadyQueriedPrincipals  The HttpUrls of principals which have been queried already, to avoid querying principals more than once.
-     * @param alreadySavedHomeSets      The HttpUrls of home sets which have been saved to database already, to avoid saving home sets
-     * more than once, which could overwrite the already set "personal" flag with `false`.
-     *
-     * @throws java.io.IOException                          on I/O errors
-     * @throws HttpException                                on HTTP errors
-     * @throws at.bitfire.dav4jvm.exception.DavException    on application-level or logical errors
-     */
-    internal fun discoverHomesets(
-        principalUrl: HttpUrl,
-        level: Int = 0,
-        alreadyQueriedPrincipals: MutableSet<HttpUrl> = mutableSetOf(),
-        alreadySavedHomeSets: MutableSet<HttpUrl> = mutableSetOf()
-    ) {
-        logger.fine("Discovering homesets of $principalUrl")
-        val relatedResources = mutableSetOf<HttpUrl>()
-
-        // Query the URL
-        val principal = DavResource(httpClient, principalUrl)
-        val personal = level == 0
-        try {
-            principal.propfind(0, *homeSetProperties) { davResponse, _ ->
-                alreadyQueriedPrincipals += davResponse.href
-
-                // If response holds home sets, save them
-                davResponse[homeSetClass]?.let { homeSets ->
-                    for (homeSetHref in homeSets.hrefs)
-                        principal.location.resolve(homeSetHref)?.let { homesetUrl ->
-                            val resolvedHomeSetUrl = UrlUtils.withTrailingSlash(homesetUrl)
-                            if (!alreadySavedHomeSets.contains(resolvedHomeSetUrl)) {
-                                homeSetRepository.insertOrUpdateByUrlBlocking(
-                                    // HomeSet is considered personal if this is the outer recursion call,
-                                    // This is because we assume the first call to query the current-user-principal
-                                    // Note: This is not be be confused with the DAV:owner attribute. Home sets can be owned by
-                                    // other principals while still being considered "personal" (belonging to the current-user-principal)
-                                    // and an owned home set need not always be personal either.
-                                    HomeSet(0, service.id, personal, resolvedHomeSetUrl)
-                                )
-                                alreadySavedHomeSets += resolvedHomeSetUrl
-                            }
-                        }
-                }
-
-                // Add related principals to be queried afterwards
-                if (personal) {
-                    val relatedResourcesTypes = listOf(
-                        // current resource is a read/write-proxy for other principals
-                        CalendarProxyReadFor::class.java,
-                        CalendarProxyWriteFor::class.java,
-                        // current resource is a member of a group (principal that can also have proxies)
-                        GroupMembership::class.java
-                    )
-                    for (type in relatedResourcesTypes)
-                        davResponse[type]?.let {
-                            for (href in it.hrefs)
-                                principal.location.resolve(href)?.let { url ->
-                                    relatedResources += url
-                                }
-                        }
-                }
-
-                // If current resource is a calendar-proxy-read/write, it's likely that its parent is a principal, too.
-                davResponse[ResourceType::class.java]?.let { resourceType ->
-                    val proxyProperties = arrayOf(
-                        ResourceType.CALENDAR_PROXY_READ,
-                        ResourceType.CALENDAR_PROXY_WRITE,
-                    )
-                    if (proxyProperties.any { resourceType.types.contains(it) })
-                        relatedResources += davResponse.href.parent()
-                }
-            }
-        } catch (e: HttpException) {
-            if (e.code/100 == 4)
-                logger.log(Level.INFO, "Ignoring Client Error 4xx while looking for ${service.type} home sets", e)
-            else
-                throw e
-        }
-
-        // query related resources
-        if (level <= 1)
-            for (resource in relatedResources)
-                if (alreadyQueriedPrincipals.contains(resource))
-                    logger.warning("$resource already queried, skipping")
-                else
-                    discoverHomesets(
-                        principalUrl = resource,
-                        level = level + 1,
-                        alreadyQueriedPrincipals = alreadyQueriedPrincipals,
-                        alreadySavedHomeSets = alreadySavedHomeSets
-                    )
-    }
-
-    /**
-     * Refreshes home-sets and their collections.
-     *
-     * Each stored home-set URL is queried (`PROPFIND`) and its collections are either saved, updated
-     * or marked as homeless - in case a collection was removed from its home-set.
-     *
-     * If a home-set URL in fact points to a collection directly, the collection will be saved with this URL,
-     * and a null value for it's home-set. Refreshing of collections without home-sets is then handled by [refreshHomelessCollections].
-     */
-    internal fun refreshHomesetsAndTheirCollections() {
-        val homesets = homeSetRepository.getByServiceBlocking(service.id).associateBy { it.url }.toMutableMap()
-        for((homeSetUrl, localHomeset) in homesets) {
-            logger.fine("Listing home set $homeSetUrl")
-
-            // To find removed collections in this homeset: create a queue from existing collections and remove every collection that
-            // is successfully rediscovered. If there are collections left, after processing is done, these are marked homeless.
-            val localHomesetCollections = db.collectionDao()
-                .getByServiceAndHomeset(service.id, localHomeset.id)
-                .associateBy { it.url }
-                .toMutableMap()
-
-            try {
-                DavResource(httpClient, homeSetUrl).propfind(1, *collectionProperties) { response, relation ->
-                    // Note: This callback may be called multiple times ([MultiResponseCallback])
-                    if (!response.isSuccess())
-                        return@propfind
-
-                    if (relation == Response.HrefRelation.SELF)
-                        // this response is about the home set itself
-                        homeSetRepository.insertOrUpdateByUrlBlocking(localHomeset.copy(
-                            displayName = response[DisplayName::class.java]?.displayName,
-                            privBind = response[CurrentUserPrivilegeSet::class.java]?.mayBind != false
-                        ))
-
-                    // in any case, check whether the response is about a usable collection
-                    var collection = Collection.fromDavResponse(response) ?: return@propfind
-                    collection = collection.copy(
-                        serviceId = service.id,
-                        homeSetId = localHomeset.id,
-                        sync = shouldPreselect(collection, homesets.values),
-                        ownerId = response[Owner::class.java]?.href  // save the principal id (collection owner)
-                            ?.let { response.href.resolve(it) }
-                            ?.let { principalUrl -> Principal.fromServiceAndUrl(service, principalUrl) }
-                            ?.let { principal -> db.principalDao().insertOrUpdate(service.id, principal) }
-                    )
-                    logger.log(Level.FINE, "Found collection", collection)
-
-                    // save or update collection if usable (ignore it otherwise)
-                    if (isUsableCollection(collection))
-                        collectionRepository.insertOrUpdateByUrlAndRememberFlags(collection)
-
-                    // Remove this collection from queue - because it was found in the home set
-                    localHomesetCollections.remove(collection.url)
-                }
-            } catch (e: HttpException) {
-                // delete home set locally if it was not accessible (40x)
-                if (e.code in arrayOf(403, 404, 410))
-                    homeSetRepository.deleteBlocking(localHomeset)
-            }
-
-            // Mark leftover (not rediscovered) collections from queue as homeless (remove association)
-            for ((_, homelessCollection) in localHomesetCollections)
-                collectionRepository.insertOrUpdateByUrlAndRememberFlags(
-                    homelessCollection.copy(homeSetId = null)
-                )
-
-        }
-    }
-
-    /**
-     * Refreshes collections which don't have a homeset.
-     *
-     * It queries each stored collection with a homeSetId of "null" and either updates or deletes (if inaccessible or unusable) them.
-     */
-    internal fun refreshHomelessCollections() {
-        val homelessCollections = db.collectionDao().getByServiceAndHomeset(service.id, null).associateBy { it.url }.toMutableMap()
-        for((url, localCollection) in homelessCollections) try {
-            DavResource(httpClient, url).propfind(0, *collectionProperties) { response, _ ->
-                if (!response.isSuccess()) {
-                    collectionRepository.delete(localCollection)
-                    return@propfind
-                }
-
-                // Save or update the collection, if usable, otherwise delete it
-                Collection.fromDavResponse(response)?.let { collection ->
-                    if (!isUsableCollection(collection))
-                        return@let
-                    collectionRepository.insertOrUpdateByUrlAndRememberFlags(collection.copy(
-                        serviceId = localCollection.serviceId,          // use same service ID as previous entry
-                        ownerId = response[Owner::class.java]?.href     // save the principal id (collection owner)
-                            ?.let { response.href.resolve(it) }
-                            ?.let { principalUrl -> Principal.fromServiceAndUrl(service, principalUrl) }
-                            ?.let { principal -> db.principalDao().insertOrUpdate(service.id, principal) }
-                    ))
-                } ?: collectionRepository.delete(localCollection)
-            }
-        } catch (e: HttpException) {
-            // delete collection locally if it was not accessible (40x)
-            if (e.code in arrayOf(403, 404, 410))
-                collectionRepository.delete(localCollection)
-            else
-                throw e
-        }
-
-    }
-
-    /**
-     * Refreshes the principals (get their current display names).
-     * Also removes principals which do not own any collections anymore.
-     */
-    internal fun refreshPrincipals() {
-        // Refresh principals (collection owner urls)
-        val principals = db.principalDao().getByService(service.id)
-        for (oldPrincipal in principals) {
-            val principalUrl = oldPrincipal.url
-            logger.fine("Querying principal $principalUrl")
-            try {
-                DavResource(httpClient, principalUrl).propfind(0, *principalProperties) { response, _ ->
-                    if (!response.isSuccess())
-                        return@propfind
-                    Principal.fromDavResponse(service.id, response)?.let { principal ->
-                        logger.fine("Got principal: $principal")
-                        db.principalDao().insertOrUpdate(service.id, principal)
-                    }
-                }
-            } catch (e: HttpException) {
-                logger.info("Principal update failed with response code ${e.code}. principalUrl=$principalUrl")
-            }
-        }
-
-        // Delete principals which don't own any collections
-        db.principalDao().getAllWithoutCollections().forEach {principal ->
-            db.principalDao().delete(principal)
-        }
-    }
-
-    /**
-     * Finds out whether given collection is usable, by checking that either
-     *  - CalDAV/CardDAV: service and collection type match, or
-     *  - WebCal: subscription source URL is not empty
-     */
-    private fun isUsableCollection(collection: Collection) =
-        (service.type == Service.TYPE_CARDDAV && collection.type == Collection.TYPE_ADDRESSBOOK) ||
-                (service.type == Service.TYPE_CALDAV && arrayOf(Collection.TYPE_CALENDAR, Collection.TYPE_WEBCAL).contains(collection.type)) ||
-                (collection.type == Collection.TYPE_WEBCAL && collection.source != null)
-
-    /**
-     * Whether to preselect the given collection for synchronisation, according to the
-     * settings [Settings.PRESELECT_COLLECTIONS] (see there for allowed values) and
-     * [Settings.PRESELECT_COLLECTIONS_EXCLUDED].
-     *
-     * A collection is considered _personal_ if it is found in one of the current-user-principal's home-sets.
-     *
-     * Before a collection is pre-selected, we check whether its URL matches the regexp in
-     * [Settings.PRESELECT_COLLECTIONS_EXCLUDED], in which case *false* is returned.
-     *
-     * @param collection    the collection to check
-     * @param homeSets      list of personal home-sets
-     * @return *true* if the collection should be preselected for synchronization; *false* otherwise
-     */
-    internal fun shouldPreselect(collection: Collection, homeSets: Iterable<HomeSet>): Boolean {
-        val shouldPreselect = settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS)
-
-        val excluded by lazy {
-            val excludedRegex = settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED)
-            if (!excludedRegex.isNullOrEmpty())
-                Regex(excludedRegex).containsMatchIn(collection.url.toString())
-            else
-                false
-        }
-
-        return when (shouldPreselect) {
-            Settings.PRESELECT_COLLECTIONS_ALL ->
-                // preselect if collection url is not excluded
-                !excluded
-
-            Settings.PRESELECT_COLLECTIONS_PERSONAL ->
-                // preselect if is personal (in a personal home-set), but not excluded
-                homeSets
-                    .filter { homeset -> homeset.personal }
-                    .map { homeset -> homeset.id }
-                    .contains(collection.homeSetId)
-                    && !excluded
-
-            else -> // don't preselect
-                false
-        }
-    }
-}

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/CollectionsWithoutHomeSetRefresher.kt

@@ -0,0 +1,73 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import at.bitfire.dav4jvm.DavResource
+import at.bitfire.dav4jvm.exception.HttpException
+import at.bitfire.dav4jvm.property.webdav.Owner
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Collection
+import at.bitfire.davdroid.db.Principal
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.repository.DavCollectionRepository
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
+import okhttp3.OkHttpClient
+
+/**
+ * Logic for refreshing the list of collections (and their related information)
+ * which do not belong to a home set.
+ */
+class CollectionsWithoutHomeSetRefresher @AssistedInject constructor(
+    @Assisted private val service: Service,
+    @Assisted private val httpClient: OkHttpClient,
+    private val db: AppDatabase,
+    private val collectionRepository: DavCollectionRepository,
+) {
+
+    @AssistedFactory
+    interface Factory {
+        fun create(service: Service, httpClient: OkHttpClient): CollectionsWithoutHomeSetRefresher
+    }
+
+    /**
+     * Refreshes collections which don't have a homeset.
+     *
+     * It queries each stored collection with a homeSetId of "null" and either updates or deletes (if inaccessible or unusable) them.
+     */
+    internal fun refreshCollectionsWithoutHomeSet() {
+        val withoutHomeSet = db.collectionDao().getByServiceAndHomeset(service.id, null).associateBy { it.url }.toMutableMap()
+        for ((url, localCollection) in withoutHomeSet) try {
+            val collectionProperties = ServiceDetectionUtils.collectionQueryProperties(service.type)
+            DavResource(httpClient, url).propfind(0, *collectionProperties) { response, _ ->
+                if (!response.isSuccess()) {
+                    collectionRepository.delete(localCollection)
+                    return@propfind
+                }
+
+                // Save or update the collection, if usable, otherwise delete it
+                Collection.fromDavResponse(response)?.let { collection ->
+                    if (!ServiceDetectionUtils.isUsableCollection(service, collection))
+                        return@let
+                    collectionRepository.insertOrUpdateByUrlRememberSync(collection.copy(
+                        serviceId = localCollection.serviceId,          // use same service ID as previous entry
+                        ownerId = response[Owner::class.java]?.href     // save the principal id (collection owner)
+                            ?.let { response.href.resolve(it) }
+                            ?.let { principalUrl -> Principal.fromServiceAndUrl(service, principalUrl) }
+                            ?.let { principal -> db.principalDao().insertOrUpdate(service.id, principal) }
+                    ))
+                } ?: collectionRepository.delete(localCollection)
+            }
+        } catch (e: HttpException) {
+            // delete collection locally if it was not accessible (40x)
+            if (e.code in arrayOf(403, 404, 410))
+                collectionRepository.delete(localCollection)
+            else
+                throw e
+        }
+    }
+
+}

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/DavResourceFinder.kt

@@ -21,16 +21,16 @@ import at.bitfire.dav4jvm.property.caldav.CalendarUserAddressSet
 import at.bitfire.dav4jvm.property.caldav.SupportedCalendarComponentSet
 import at.bitfire.dav4jvm.property.carddav.AddressbookDescription
 import at.bitfire.dav4jvm.property.carddav.AddressbookHomeSet
+import at.bitfire.dav4jvm.property.common.HrefListProperty
 import at.bitfire.dav4jvm.property.webdav.CurrentUserPrincipal
 import at.bitfire.dav4jvm.property.webdav.CurrentUserPrivilegeSet
 import at.bitfire.dav4jvm.property.webdav.DisplayName
-import at.bitfire.dav4jvm.property.webdav.HrefListProperty
 import at.bitfire.dav4jvm.property.webdav.ResourceType
 import at.bitfire.davdroid.db.Collection
-import at.bitfire.davdroid.db.Credentials
 import at.bitfire.davdroid.log.StringHandler
 import at.bitfire.davdroid.network.DnsRecordResolver
 import at.bitfire.davdroid.network.HttpClient
+import at.bitfire.davdroid.settings.Credentials
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory
 import dagger.assisted.AssistedInject
@@ -88,7 +88,7 @@ class DavResourceFinder @AssistedInject constructor(
             if (credentials != null)
                 authenticate(
                     host = null,
-                    credentials = credentials
+                    getCredentials = { credentials }
                 )
             }
         .build()

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/HomeSetRefresher.kt

@@ -0,0 +1,162 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import at.bitfire.dav4jvm.DavResource
+import at.bitfire.dav4jvm.Response
+import at.bitfire.dav4jvm.exception.HttpException
+import at.bitfire.dav4jvm.property.webdav.CurrentUserPrivilegeSet
+import at.bitfire.dav4jvm.property.webdav.DisplayName
+import at.bitfire.dav4jvm.property.webdav.Owner
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Collection
+import at.bitfire.davdroid.db.HomeSet
+import at.bitfire.davdroid.db.Principal
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.repository.DavCollectionRepository
+import at.bitfire.davdroid.repository.DavHomeSetRepository
+import at.bitfire.davdroid.settings.Settings
+import at.bitfire.davdroid.settings.SettingsManager
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
+import okhttp3.OkHttpClient
+import java.util.logging.Level
+import java.util.logging.Logger
+
+/**
+ * Used to update the list of synchronizable collections
+ */
+class HomeSetRefresher @AssistedInject constructor(
+    @Assisted private val service: Service,
+    @Assisted private val httpClient: OkHttpClient,
+    private val db: AppDatabase,
+    private val logger: Logger,
+    private val collectionRepository: DavCollectionRepository,
+    private val homeSetRepository: DavHomeSetRepository,
+    private val settings: SettingsManager
+) {
+
+    @AssistedFactory
+    interface Factory {
+        fun create(service: Service, httpClient: OkHttpClient): HomeSetRefresher
+    }
+
+    /**
+     * Refreshes home-sets and their collections.
+     *
+     * Each stored home-set URL is queried (`PROPFIND`) and its collections are either saved, updated
+     * or marked as "without home-set" - in case a collection was removed from its home-set.
+     *
+     * If a home-set URL in fact points to a collection directly, the collection will be saved with this URL,
+     * and a null value for it's home-set. Refreshing of collections without home-sets is then handled by [CollectionsWithoutHomeSetRefresher.refreshCollectionsWithoutHomeSet].
+     */
+    internal fun refreshHomesetsAndTheirCollections() {
+        val homesets = homeSetRepository.getByServiceBlocking(service.id).associateBy { it.url }.toMutableMap()
+        for ((homeSetUrl, localHomeset) in homesets) {
+            logger.fine("Listing home set $homeSetUrl")
+
+            // To find removed collections in this homeset: create a queue from existing collections and remove every collection that
+            // is successfully rediscovered. If there are collections left, after processing is done, these are marked as "without home-set".
+            val localHomesetCollections = db.collectionDao()
+                .getByServiceAndHomeset(service.id, localHomeset.id)
+                .associateBy { it.url }
+                .toMutableMap()
+
+            try {
+                val collectionProperties = ServiceDetectionUtils.collectionQueryProperties(service.type)
+                DavResource(httpClient, homeSetUrl).propfind(1, *collectionProperties) { response, relation ->
+                    // Note: This callback may be called multiple times ([MultiResponseCallback])
+                    if (!response.isSuccess())
+                        return@propfind
+
+                    if (relation == Response.HrefRelation.SELF)
+                    // this response is about the home set itself
+                        homeSetRepository.insertOrUpdateByUrlBlocking(
+                            localHomeset.copy(
+                                displayName = response[DisplayName::class.java]?.displayName,
+                                privBind = response[CurrentUserPrivilegeSet::class.java]?.mayBind != false
+                            )
+                        )
+
+                    // in any case, check whether the response is about a usable collection
+                    var collection = Collection.fromDavResponse(response) ?: return@propfind
+                    collection = collection.copy(
+                        serviceId = service.id,
+                        homeSetId = localHomeset.id,
+                        sync = shouldPreselect(collection, homesets.values),
+                        ownerId = response[Owner::class.java]?.href  // save the principal id (collection owner)
+                            ?.let { response.href.resolve(it) }
+                            ?.let { principalUrl -> Principal.fromServiceAndUrl(service, principalUrl) }
+                            ?.let { principal -> db.principalDao().insertOrUpdate(service.id, principal) }
+                    )
+                    logger.log(Level.FINE, "Found collection", collection)
+
+                    // save or update collection if usable (ignore it otherwise)
+                    if (ServiceDetectionUtils.isUsableCollection(service, collection))
+                        collectionRepository.insertOrUpdateByUrlRememberSync(collection)
+
+                    // Remove this collection from queue - because it was found in the home set
+                    localHomesetCollections.remove(collection.url)
+                }
+            } catch (e: HttpException) {
+                // delete home set locally if it was not accessible (40x)
+                if (e.code in arrayOf(403, 404, 410))
+                    homeSetRepository.deleteBlocking(localHomeset)
+            }
+
+            // Mark leftover (not rediscovered) collections from queue as "without home-set" (remove association)
+            for ((_, collection) in localHomesetCollections)
+                collectionRepository.insertOrUpdateByUrlRememberSync(
+                    collection.copy(homeSetId = null)
+                )
+
+        }
+    }
+
+    /**
+     * Whether to preselect the given collection for synchronisation, according to the
+     * settings [Settings.PRESELECT_COLLECTIONS] (see there for allowed values) and
+     * [Settings.PRESELECT_COLLECTIONS_EXCLUDED].
+     *
+     * A collection is considered _personal_ if it is found in one of the current-user-principal's home-sets.
+     *
+     * Before a collection is pre-selected, we check whether its URL matches the regexp in
+     * [Settings.PRESELECT_COLLECTIONS_EXCLUDED], in which case *false* is returned.
+     *
+     * @param collection    the collection to check
+     * @param homeSets      list of personal home-sets
+     * @return *true* if the collection should be preselected for synchronization; *false* otherwise
+     */
+    internal fun shouldPreselect(collection: Collection, homeSets: Iterable<HomeSet>): Boolean {
+        val shouldPreselect = settings.getIntOrNull(Settings.PRESELECT_COLLECTIONS)
+
+        val excluded by lazy {
+            val excludedRegex = settings.getString(Settings.PRESELECT_COLLECTIONS_EXCLUDED)
+            if (!excludedRegex.isNullOrEmpty())
+                Regex(excludedRegex).containsMatchIn(collection.url.toString())
+            else
+                false
+        }
+
+        return when (shouldPreselect) {
+            Settings.PRESELECT_COLLECTIONS_ALL ->
+                // preselect if collection url is not excluded
+                !excluded
+
+            Settings.PRESELECT_COLLECTIONS_PERSONAL ->
+                // preselect if is personal (in a personal home-set), but not excluded
+                homeSets
+                    .filter { homeset -> homeset.personal }
+                    .map { homeset -> homeset.id }
+                    .contains(collection.homeSetId)
+                        && !excluded
+
+            else -> // don't preselect
+                false
+        }
+    }
+
+}

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/PrincipalsRefresher.kt

@@ -0,0 +1,73 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import at.bitfire.dav4jvm.DavResource
+import at.bitfire.dav4jvm.exception.HttpException
+import at.bitfire.dav4jvm.property.webdav.DisplayName
+import at.bitfire.dav4jvm.property.webdav.ResourceType
+import at.bitfire.davdroid.db.AppDatabase
+import at.bitfire.davdroid.db.Principal
+import at.bitfire.davdroid.db.Service
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
+import okhttp3.OkHttpClient
+import java.util.logging.Logger
+
+/**
+ * Used to update the principals (their current display names) and delete those without collections.
+ */
+class PrincipalsRefresher @AssistedInject constructor(
+    @Assisted private val service: Service,
+    @Assisted private val httpClient: OkHttpClient,
+    private val db: AppDatabase,
+    private val logger: Logger
+) {
+
+    @AssistedFactory
+    interface Factory {
+        fun create(service: Service, httpClient: OkHttpClient): PrincipalsRefresher
+    }
+
+    /**
+     * Principal properties to ask the server for.
+     */
+    private val principalProperties = arrayOf(
+        DisplayName.NAME,
+        ResourceType.NAME
+    )
+
+    /**
+     * Refreshes the principals (get their current display names).
+     * Also removes principals which do not own any collections anymore.
+     */
+    fun refreshPrincipals() {
+        // Refresh principals (collection owner urls)
+        val principals = db.principalDao().getByService(service.id)
+        for (oldPrincipal in principals) {
+            val principalUrl = oldPrincipal.url
+            logger.fine("Querying principal $principalUrl")
+            try {
+                DavResource(httpClient, principalUrl).propfind(0, *principalProperties) { response, _ ->
+                    if (!response.isSuccess())
+                        return@propfind
+                    Principal.fromDavResponse(service.id, response)?.let { principal ->
+                        logger.fine("Got principal: $principal")
+                        db.principalDao().insertOrUpdate(service.id, principal)
+                    }
+                }
+            } catch (e: HttpException) {
+                logger.info("Principal update failed with response code ${e.code}. principalUrl=$principalUrl")
+            }
+        }
+
+        // Delete principals which don't own any collections
+        db.principalDao().getAllWithoutCollections().forEach { principal ->
+            db.principalDao().delete(principal)
+        }
+    }
+
+}

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/RefreshCollectionsWorker.kt

@@ -62,11 +62,14 @@ import java.util.logging.Logger
 class RefreshCollectionsWorker @AssistedInject constructor(
     @Assisted appContext: Context,
     @Assisted workerParams: WorkerParameters,
-    private val collectionListRefresherFactory: CollectionListRefresher.Factory,
+    private val collectionsWithoutHomeSetRefresherFactory: CollectionsWithoutHomeSetRefresher.Factory,
+    private val homeSetRefresherFactory: HomeSetRefresher.Factory,
     private val httpClientBuilder: HttpClient.Builder,
     private val logger: Logger,
     private val notificationRegistry: NotificationRegistry,
+    private val principalsRefresherFactory: PrincipalsRefresher.Factory,
     private val pushRegistrationManager: PushRegistrationManager,
+    private val serviceRefresherFactory: ServiceRefresher.Factory,
     serviceRepository: DavServiceRepository
 ): CoroutineWorker(appContext, workerParams) {
 
@@ -156,22 +159,25 @@ class RefreshCollectionsWorker @AssistedInject constructor(
                 .use { httpClient ->
                     runInterruptible {
                         val httpClient = httpClient.okHttpClient
-                        val refresher = collectionListRefresherFactory.create(service, httpClient)
+                        val refresher = collectionsWithoutHomeSetRefresherFactory.create(service, httpClient)
 
                         // refresh home set list (from principal url)
                         service.principal?.let { principalUrl ->
                             logger.fine("Querying principal $principalUrl for home sets")
-                            refresher.discoverHomesets(principalUrl)
+                            val serviceRefresher = serviceRefresherFactory.create(service, httpClient)
+                            serviceRefresher.discoverHomesets(principalUrl)
                         }
 
                         // refresh home sets and their member collections
-                        refresher.refreshHomesetsAndTheirCollections()
+                        homeSetRefresherFactory.create(service, httpClient)
+                            .refreshHomesetsAndTheirCollections()
 
                         // also refresh collections without a home set
-                        refresher.refreshHomelessCollections()
+                        refresher.refreshCollectionsWithoutHomeSet()
 
                         // Lastly, refresh the principals (collection owners)
-                        refresher.refreshPrincipals()
+                        val principalsRefresher = principalsRefresherFactory.create(service, httpClient)
+                        principalsRefresher.refreshPrincipals()
                     }
                 }
 

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/ServiceDetectionUtils.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import at.bitfire.dav4jvm.Property
+import at.bitfire.dav4jvm.property.caldav.CalendarColor
+import at.bitfire.dav4jvm.property.caldav.CalendarDescription
+import at.bitfire.dav4jvm.property.caldav.CalendarTimezone
+import at.bitfire.dav4jvm.property.caldav.CalendarTimezoneId
+import at.bitfire.dav4jvm.property.caldav.Source
+import at.bitfire.dav4jvm.property.caldav.SupportedCalendarComponentSet
+import at.bitfire.dav4jvm.property.carddav.AddressbookDescription
+import at.bitfire.dav4jvm.property.push.PushTransports
+import at.bitfire.dav4jvm.property.push.Topic
+import at.bitfire.dav4jvm.property.webdav.CurrentUserPrivilegeSet
+import at.bitfire.dav4jvm.property.webdav.DisplayName
+import at.bitfire.dav4jvm.property.webdav.Owner
+import at.bitfire.dav4jvm.property.webdav.ResourceType
+import at.bitfire.davdroid.db.Collection
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.db.ServiceType
+
+object ServiceDetectionUtils {
+
+    /**
+     * WebDAV properties to ask for in a PROPFIND request on a collection.
+     */
+    fun collectionQueryProperties(@ServiceType serviceType: String): Array<Property.Name> =
+        arrayOf(                        // generic WebDAV properties
+            CurrentUserPrivilegeSet.NAME,
+            DisplayName.NAME,
+            Owner.NAME,
+            ResourceType.NAME,
+            PushTransports.NAME,        // WebDAV-Push
+            Topic.NAME
+        ) + when (serviceType) {       // service-specific CalDAV/CardDAV properties
+            Service.TYPE_CARDDAV -> arrayOf(
+                AddressbookDescription.NAME
+            )
+
+            Service.TYPE_CALDAV -> arrayOf(
+                CalendarColor.NAME,
+                CalendarDescription.NAME,
+                CalendarTimezone.NAME,
+                CalendarTimezoneId.NAME,
+                SupportedCalendarComponentSet.NAME,
+                Source.NAME
+            )
+
+            else -> throw IllegalArgumentException()
+        }
+
+    /**
+     * Finds out whether given collection is usable for synchronization, by checking that either
+     *
+     *  - CalDAV/CardDAV: service and collection type match, or
+     *  - WebCal: subscription source URL is not empty.
+     */
+    fun isUsableCollection(service: Service, collection: Collection) =
+        (service.type == Service.TYPE_CARDDAV && collection.type == Collection.TYPE_ADDRESSBOOK) ||
+                (service.type == Service.TYPE_CALDAV && arrayOf(Collection.TYPE_CALENDAR, Collection.TYPE_WEBCAL).contains(collection.type)) ||
+                (collection.type == Collection.TYPE_WEBCAL && collection.source != null)
+
+}

app/src/main/kotlin/at/bitfire/davdroid/servicedetection/ServiceRefresher.kt

@@ -0,0 +1,178 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.servicedetection
+
+import at.bitfire.dav4jvm.DavResource
+import at.bitfire.dav4jvm.Property
+import at.bitfire.dav4jvm.UrlUtils
+import at.bitfire.dav4jvm.exception.HttpException
+import at.bitfire.dav4jvm.property.caldav.CalendarHomeSet
+import at.bitfire.dav4jvm.property.caldav.CalendarProxyReadFor
+import at.bitfire.dav4jvm.property.caldav.CalendarProxyWriteFor
+import at.bitfire.dav4jvm.property.carddav.AddressbookHomeSet
+import at.bitfire.dav4jvm.property.common.HrefListProperty
+import at.bitfire.dav4jvm.property.webdav.DisplayName
+import at.bitfire.dav4jvm.property.webdav.GroupMembership
+import at.bitfire.dav4jvm.property.webdav.ResourceType
+import at.bitfire.davdroid.db.HomeSet
+import at.bitfire.davdroid.db.Service
+import at.bitfire.davdroid.repository.DavHomeSetRepository
+import at.bitfire.davdroid.util.DavUtils.parent
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
+import okhttp3.HttpUrl
+import okhttp3.OkHttpClient
+import java.util.logging.Level
+import java.util.logging.Logger
+
+/**
+ * ServiceRefresher is used to discover and save home sets of a given service.
+ */
+class ServiceRefresher @AssistedInject constructor(
+    @Assisted private val service: Service,
+    @Assisted private val httpClient: OkHttpClient,
+    private val logger: Logger,
+    private val homeSetRepository: DavHomeSetRepository
+) {
+
+    @AssistedFactory
+    interface Factory {
+        fun create(service: Service, httpClient: OkHttpClient): ServiceRefresher
+    }
+
+    /**
+     * Home-set class to use depending on the given service type.
+     */
+    private val homeSetClass: Class<out HrefListProperty> =
+        when (service.type) {
+            Service.TYPE_CARDDAV -> AddressbookHomeSet::class.java
+            Service.TYPE_CALDAV -> CalendarHomeSet::class.java
+            else -> throw IllegalArgumentException()
+        }
+
+    /**
+     * Home-set properties to ask for in a PROPFIND request to the principal URL,
+     * depending on the given service type.
+     */
+    private val homeSetProperties: Array<Property.Name> =
+        arrayOf(                        // generic WebDAV properties
+            DisplayName.NAME,
+            GroupMembership.NAME,
+            ResourceType.NAME
+        ) + when (service.type) {       // service-specific CalDAV/CardDAV properties
+            Service.TYPE_CARDDAV -> arrayOf(
+                AddressbookHomeSet.NAME,
+            )
+
+            Service.TYPE_CALDAV -> arrayOf(
+                CalendarHomeSet.NAME,
+                CalendarProxyReadFor.NAME,
+                CalendarProxyWriteFor.NAME
+            )
+
+            else -> throw IllegalArgumentException()
+        }
+
+    /**
+     * Starting at given principal URL, tries to recursively find and save all user relevant home sets.
+     *
+     * @param principalUrl              URL of principal to query (user-provided principal or current-user-principal)
+     * @param level                     Current recursion level (limited to 0, 1 or 2):
+     *   - 0: We assume found home sets belong to the current-user-principal
+     *   - 1 or 2: We assume found home sets don't directly belong to the current-user-principal
+     * @param alreadyQueriedPrincipals  The HttpUrls of principals which have been queried already, to avoid querying principals more than once.
+     * @param alreadySavedHomeSets      The HttpUrls of home sets which have been saved to database already, to avoid saving home sets
+     * more than once, which could overwrite the already set "personal" flag with `false`.
+     *
+     * @throws java.io.IOException                          on I/O errors
+     * @throws HttpException                                on HTTP errors
+     * @throws at.bitfire.dav4jvm.exception.DavException    on application-level or logical errors
+     */
+    internal fun discoverHomesets(
+        principalUrl: HttpUrl,
+        level: Int = 0,
+        alreadyQueriedPrincipals: MutableSet<HttpUrl> = mutableSetOf(),
+        alreadySavedHomeSets: MutableSet<HttpUrl> = mutableSetOf()
+    ) {
+        logger.fine("Discovering homesets of $principalUrl")
+        val relatedResources = mutableSetOf<HttpUrl>()
+
+        // Query the URL
+        val principal = DavResource(httpClient, principalUrl)
+        val personal = level == 0
+        try {
+            principal.propfind(0, *homeSetProperties) { davResponse, _ ->
+                alreadyQueriedPrincipals += davResponse.href
+
+                // If response holds home sets, save them
+                davResponse[homeSetClass]?.let { homeSets ->
+                    for (homeSetHref in homeSets.hrefs)
+                        principal.location.resolve(homeSetHref)?.let { homesetUrl ->
+                            val resolvedHomeSetUrl = UrlUtils.withTrailingSlash(homesetUrl)
+                            if (!alreadySavedHomeSets.contains(resolvedHomeSetUrl)) {
+                                homeSetRepository.insertOrUpdateByUrlBlocking(
+                                    // HomeSet is considered personal if this is the outer recursion call,
+                                    // This is because we assume the first call to query the current-user-principal
+                                    // Note: This is not be be confused with the DAV:owner attribute. Home sets can be owned by
+                                    // other principals while still being considered "personal" (belonging to the current-user-principal)
+                                    // and an owned home set need not always be personal either.
+                                    HomeSet(0, service.id, personal, resolvedHomeSetUrl)
+                                )
+                                alreadySavedHomeSets += resolvedHomeSetUrl
+                            }
+                        }
+                }
+
+                // Add related principals to be queried afterwards
+                if (personal) {
+                    val relatedResourcesTypes = listOf(
+                        // current resource is a read/write-proxy for other principals
+                        CalendarProxyReadFor::class.java,
+                        CalendarProxyWriteFor::class.java,
+                        // current resource is a member of a group (principal that can also have proxies)
+                        GroupMembership::class.java
+                    )
+                    for (type in relatedResourcesTypes)
+                        davResponse[type]?.let {
+                            for (href in it.hrefs)
+                                principal.location.resolve(href)?.let { url ->
+                                    relatedResources += url
+                                }
+                        }
+                }
+
+                // If current resource is a calendar-proxy-read/write, it's likely that its parent is a principal, too.
+                davResponse[ResourceType::class.java]?.let { resourceType ->
+                    val proxyProperties = arrayOf(
+                        ResourceType.CALENDAR_PROXY_READ,
+                        ResourceType.CALENDAR_PROXY_WRITE,
+                    )
+                    if (proxyProperties.any { resourceType.types.contains(it) })
+                        relatedResources += davResponse.href.parent()
+                }
+            }
+        } catch (e: HttpException) {
+            if (e.code / 100 == 4)
+                logger.log(Level.INFO, "Ignoring Client Error 4xx while looking for ${service.type} home sets", e)
+            else
+                throw e
+        }
+
+        // query related resources
+        if (level <= 1)
+            for (resource in relatedResources)
+                if (alreadyQueriedPrincipals.contains(resource))
+                    logger.warning("$resource already queried, skipping")
+                else
+                    discoverHomesets(
+                        principalUrl = resource,
+                        level = level + 1,
+                        alreadyQueriedPrincipals = alreadyQueriedPrincipals,
+                        alreadySavedHomeSets = alreadySavedHomeSets
+                    )
+    }
+
+}

app/src/main/kotlin/at/bitfire/davdroid/settings/AccountSettings.kt

@@ -11,7 +11,6 @@ import android.os.Looper
 import androidx.annotation.WorkerThread
 import androidx.core.os.bundleOf
 import at.bitfire.davdroid.R
-import at.bitfire.davdroid.db.Credentials
 import at.bitfire.davdroid.settings.AccountSettings.Companion.CREDENTIALS_LOCK
 import at.bitfire.davdroid.settings.AccountSettings.Companion.CREDENTIALS_LOCK_AT_LOGIN_AND_SETTINGS
 import at.bitfire.davdroid.settings.migration.AccountSettingsMigration
@@ -125,7 +124,13 @@ class AccountSettings @AssistedInject constructor(
         accountManager.setAndVerifyUserData(account, KEY_CERTIFICATE_ALIAS, credentials.certificateAlias)
 
         // OAuth
-        accountManager.setAndVerifyUserData(account, KEY_AUTH_STATE, credentials.authState?.jsonSerializeString())
+        credentials.authState?.let { authState ->
+            updateAuthState(authState)
+        }
+    }
+
+    fun updateAuthState(authState: AuthState) {
+        accountManager.setAndVerifyUserData(account, KEY_AUTH_STATE, authState.jsonSerializeString())
     }
 
     /**
@@ -172,7 +177,7 @@ class AccountSettings @AssistedInject constructor(
             SyncDataType.EVENTS -> KEY_SYNC_INTERVAL_CALENDARS
             SyncDataType.TASKS -> KEY_SYNC_INTERVAL_TASKS
         }
-        val newValue = if (seconds == null) SYNC_INTERVAL_MANUALLY else seconds
+        val newValue = seconds ?: SYNC_INTERVAL_MANUALLY
         accountManager.setAndVerifyUserData(account, key, newValue.toString())
 
         automaticSyncManager.updateAutomaticSync(account, dataType)
@@ -349,7 +354,12 @@ class AccountSettings @AssistedInject constructor(
 
     companion object {
 
-        const val CURRENT_VERSION = 20
+        /**
+         * Current (usually the newest) account settings version. It's used to
+         * determine whether a migration ([AccountSettingsMigration])
+         * should be performed.
+         */
+        const val CURRENT_VERSION = 21
         const val KEY_SETTINGS_VERSION = "version"
 
         const val KEY_SYNC_INTERVAL_ADDRESSBOOKS = "sync_interval_addressbooks"

app/src/main/kotlin/at/bitfire/davdroid/settings/Credentials.kt

@@ -2,16 +2,26 @@
  * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
  */
 
-package at.bitfire.davdroid.db
+package at.bitfire.davdroid.settings
 
 import net.openid.appauth.AuthState
 
+/**
+ * Represents credentials that are used to authenticate against a CalDAV/CardDAV/WebDAV server.
+ *
+ * Note: [authState] can change from request to request, so make sure that you have an up-to-date
+ * copy when using it.
+ */
 data class Credentials(
+    /** username for Basic / Digest auth */
     val username: String? = null,
+    /** password for Basic / Digest auth */
     val password: CharArray? = null,
 
+    /** alias of an client certificate that is present on the system */
     val certificateAlias: String? = null,
 
+    /** OAuth authorization state */
     val authState: AuthState? = null
 ) {
 
@@ -26,7 +36,7 @@ data class Credentials(
         if (certificateAlias != null)
             s += "certificateAlias=$certificateAlias"
 
-        if (authState != null)
+        if (authState != null)      // contains sensitive information (refresh token, access token)
             s += "authState=${authState.jsonSerializeString()}"
 
         return "Credentials(" + s.joinToString(", ") + ")"

app/src/main/kotlin/at/bitfire/davdroid/settings/Settings.kt

@@ -5,6 +5,7 @@
 package at.bitfire.davdroid.settings
 
 import androidx.appcompat.app.AppCompatDelegate
+import at.bitfire.davdroid.settings.Settings.PRESELECT_COLLECTIONS_EXCLUDED
 
 object Settings {
 
@@ -60,5 +61,9 @@ object Settings {
 
     /** whether all address books are forced to be read-only */
     const val FORCE_READ_ONLY_ADDRESSBOOKS = "force_read_only_addressbooks"
+
+
+    /** max. number of accounts */
+    const val MAX_ACCOUNTS = "max_accounts"
     
-}
+}

app/src/main/kotlin/at/bitfire/davdroid/settings/migration/AccountSettingsMigration.kt

@@ -10,7 +10,8 @@ import at.bitfire.davdroid.settings.AccountSettings
 interface AccountSettingsMigration {
 
     /**
-     * Migrate the account settings from the old version to the new version.
+     * Migrate the account settings from the old version to the new version which
+     * is set in [AccountSettings.CURRENT_VERSION].
      *
      * **The new (target) version number is registered in the Hilt module as [Int] key of the multi-binding of [AccountSettings].**
      *

app/src/main/kotlin/at/bitfire/davdroid/settings/migration/AccountSettingsMigration10.kt

@@ -8,10 +8,11 @@ import android.accounts.Account
 import android.content.Context
 import android.content.pm.PackageManager
 import android.provider.CalendarContract
+import android.provider.CalendarContract.Calendars
+import android.provider.CalendarContract.Reminders
 import androidx.core.content.ContextCompat
 import androidx.core.content.contentValuesOf
 import at.bitfire.davdroid.resource.LocalTask
-import at.bitfire.ical4android.AndroidCalendar
 import at.bitfire.ical4android.TaskProvider
 import at.techbee.jtx.JtxContract.asSyncAdapter
 import dagger.Binds
@@ -45,8 +46,14 @@ class AccountSettingsMigration10 @Inject constructor(
         if (ContextCompat.checkSelfPermission(context, android.Manifest.permission.WRITE_CALENDAR) == PackageManager.PERMISSION_GRANTED)
             context.contentResolver.acquireContentProviderClient(CalendarContract.AUTHORITY)?.use { provider ->
                 provider.update(
-                    CalendarContract.Calendars.CONTENT_URI.asSyncAdapter(account),
-                    AndroidCalendar.calendarBaseValues, null, null)
+                    Calendars.CONTENT_URI.asSyncAdapter(account),
+                    contentValuesOf(
+                        Calendars.ALLOWED_REMINDERS to arrayOf(
+                            Reminders.METHOD_DEFAULT,
+                            Reminders.METHOD_ALERT,
+                            Reminders.METHOD_EMAIL
+                        ).joinToString(",") { it.toString() }
+                    ), null, null)
             }
     }
 

app/src/main/kotlin/at/bitfire/davdroid/settings/migration/AccountSettingsMigration12.kt

@@ -12,8 +12,8 @@ import android.provider.CalendarContract
 import android.util.Base64
 import androidx.core.content.ContextCompat
 import androidx.core.content.contentValuesOf
-import at.bitfire.ical4android.AndroidEvent
 import at.bitfire.ical4android.UnknownProperty
+import at.bitfire.synctools.storage.calendar.AndroidEvent2
 import at.techbee.jtx.JtxContract.asSyncAdapter
 import dagger.Binds
 import dagger.Module
@@ -69,7 +69,7 @@ class AccountSettingsMigration12 @Inject constructor(
                                     val property = UnknownProperty.fromJsonString(rawValue)
                                     if (property is Url) {  // rewrite to MIMETYPE_URL
                                         val newValues = contentValuesOf(
-                                            CalendarContract.ExtendedProperties.NAME to AndroidEvent.EXTNAME_URL,
+                                            CalendarContract.ExtendedProperties.NAME to AndroidEvent2.EXTNAME_URL,
                                             CalendarContract.ExtendedProperties.VALUE to property.value
                                         )
                                         provider.update(uri, newValues, null, null)
@@ -77,7 +77,7 @@ class AccountSettingsMigration12 @Inject constructor(
                                 } catch (e: Exception) {
                                     logger.log(
                                         Level.WARNING,
-                                        "Couldn't rewrite URL from unknown property to ${AndroidEvent.EXTNAME_URL}",
+                                        "Couldn't rewrite URL from unknown property to ${AndroidEvent2.EXTNAME_URL}",
                                         e
                                     )
                                 }

app/src/main/kotlin/at/bitfire/davdroid/settings/migration/AccountSettingsMigration20.kt

@@ -7,7 +7,7 @@ package at.bitfire.davdroid.settings.migration
 import android.accounts.Account
 import android.accounts.AccountManager
 import android.content.Context
-import android.provider.CalendarContract.Calendars
+import android.provider.CalendarContract
 import androidx.annotation.OpenForTesting
 import androidx.core.content.contentValuesOf
 import at.bitfire.davdroid.db.Service
@@ -18,6 +18,7 @@ import at.bitfire.davdroid.resource.LocalCalendarStore
 import at.bitfire.davdroid.resource.LocalTaskList
 import at.bitfire.davdroid.sync.TasksAppManager
 import at.bitfire.ical4android.JtxCollection
+import at.bitfire.synctools.storage.calendar.AndroidCalendarProvider
 import at.techbee.jtx.JtxContract
 import dagger.Binds
 import dagger.Module
@@ -64,12 +65,7 @@ class AccountSettingsMigration20 @Inject constructor(
 
     @OpenForTesting
     internal fun migrateAddressBooks(account: Account, cardDavServiceId: Long) {
-        try {
-            addressBookStore.acquireContentProvider()
-        } catch (_: SecurityException) {
-            // no contacts permission
-            null
-        }?.use { provider ->
+        addressBookStore.acquireContentProvider()?.use { provider ->
             for (addressBook in addressBookStore.getAll(account, provider)) {
                 val url = accountManager.getUserData(addressBook.addressBookAccount, ADDRESS_BOOK_USER_DATA_URL) ?: continue
                 val collection = collectionRepository.getByServiceAndUrl(cardDavServiceId, url) ?: continue
@@ -80,35 +76,25 @@ class AccountSettingsMigration20 @Inject constructor(
 
     @OpenForTesting
     internal fun migrateCalendars(account: Account, calDavServiceId: Long) {
-        try {
-            calendarStore.acquireContentProvider()
-        } catch (_: SecurityException) {
-            // no contacts permission
-            null
-        }?.use { provider ->
-            for (calendar in calendarStore.getAll(account, provider))
-                provider.query(calendar.calendarSyncURI(), arrayOf(Calendars.NAME), null, null, null)?.use { cursor ->
-                    if (cursor.moveToFirst())
-                        cursor.getString(0)?.let { url ->
-                            collectionRepository.getByServiceAndUrl(calDavServiceId, url)?.let { collection ->
-                                calendar.update(contentValuesOf(
-                                    Calendars._SYNC_ID to collection.id
-                                ))
-                            }
-                        }
+        calendarStore.acquireContentProvider()?.use { client ->
+            val calendarProvider = AndroidCalendarProvider(account, client)
+            // for each calendar, assign _SYNC_ID := ID if collection (identified by NAME field = URL)
+            for (calendar in calendarProvider.findCalendars()) {
+                val url = calendar.name ?: continue
+                collectionRepository.getByServiceAndUrl(calDavServiceId, url)?.let { collection ->
+                    calendar.update(contentValuesOf(
+                        CalendarContract.Calendars._SYNC_ID to collection.id
+                    ))
                 }
+
+            }
         }
     }
 
     @OpenForTesting
     internal fun migrateTaskLists(account: Account, calDavServiceId: Long) {
         val taskListStore = tasksAppManager.getDataStore() ?: /* no tasks app */ return
-        try {
-            taskListStore.acquireContentProvider()
-        } catch (_: SecurityException) {
-            // no tasks permission
-            null
-        }?.use { provider ->
+        taskListStore.acquireContentProvider()?.use { provider ->
             for (taskList in taskListStore.getAll(account, provider)) {
                 when (taskList) {
                     is LocalTaskList -> {       // tasks.org, OpenTasks

app/src/main/kotlin/at/bitfire/davdroid/settings/migration/AccountSettingsMigration21.kt

@@ -0,0 +1,76 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.settings.migration
+
+import android.accounts.Account
+import android.accounts.AccountManager
+import android.content.Context
+import android.os.Build
+import android.os.Bundle
+import android.provider.CalendarContract
+import android.provider.ContactsContract
+import at.bitfire.davdroid.R
+import at.bitfire.davdroid.sync.adapter.SyncFrameworkIntegration
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.android.qualifiers.ApplicationContext
+import dagger.hilt.components.SingletonComponent
+import dagger.multibindings.IntKey
+import dagger.multibindings.IntoMap
+import java.util.logging.Logger
+import javax.inject.Inject
+
+/**
+ * On Android 14+ the pending sync state of the Sync Adapter Framework is not handled correctly.
+ * As a workaround we cancel incoming sync requests (clears pending flag) after enqueuing our own
+ * sync worker (work manager). With version 4.5.3 we started cancelling pending syncs for DAVx5
+ * accounts, but forgot to do that for address book accounts. With version 4.5.4 we also cancel
+ * those, but only when contact data of an address book has been edited.
+ *
+ * This migration cancels (once only) any possibly still wrongly pending address book and calendar
+ * (+tasks) account syncs.
+ */
+class AccountSettingsMigration21 @Inject constructor(
+    @ApplicationContext private val context: Context,
+    private val syncFrameworkIntegration: SyncFrameworkIntegration,
+    private val logger: Logger
+): AccountSettingsMigration {
+
+    private val accountManager = AccountManager.get(context)
+
+    private val calendarAccountType = context.getString(R.string.account_type)
+    private val addressBookAccountType = context.getString(R.string.account_type_address_book)
+
+    override fun migrate(account: Account) {
+        if (Build.VERSION.SDK_INT >= 34) {
+            // Cancel any (after an update) possibly forever pending calendar (+tasks) account syncs
+            cancelSyncs(calendarAccountType, CalendarContract.AUTHORITY)
+
+            // Cancel any (after an update) possibly forever pending address book account syncs
+            cancelSyncs(addressBookAccountType, ContactsContract.AUTHORITY)
+        }
+    }
+
+    /**
+     * Cancels any (possibly forever pending) syncs for the accounts of given account type for all
+     * authorities.
+     */
+    private fun cancelSyncs(accountType: String, authority: String) {
+        accountManager.getAccountsByType(accountType).forEach { account ->
+            logger.info("Android 14+: Canceling all (possibly forever pending) syncs for $account")
+            syncFrameworkIntegration.cancelSync(account, authority, Bundle())
+        }
+    }
+
+    @Module
+    @InstallIn(SingletonComponent::class)
+    abstract class AccountSettingsMigrationModule {
+        @Binds @IntoMap
+        @IntKey(21)
+        abstract fun provide(impl: AccountSettingsMigration21): AccountSettingsMigration
+    }
+
+}