From fffe38a2b0af85e7a4d56ae4d8c024bb5d3e035e Mon Sep 17 00:00:00 2001
From: Gordon Messmer <gmessmer@redhat.com>
Date: Sat, 14 Mar 2026 20:23:31 -0700
Subject: [PATCH] common: Report the age of the configuration

This change will allow applications to determine if their data
is older than the flatpak configuration, to aid cache invalidation.
---
 common/flatpak-installation.c      | 35 ++++++++++++++++++++++++
 common/flatpak-installation.h      |  1 +
 doc/reference/flatpak-sections.txt |  1 +
 tests/testlibrary.c                | 44 ++++++++++++++++++++++++++++++
 4 files changed, 81 insertions(+)

diff --git a/common/flatpak-installation.c b/common/flatpak-installation.c
index 94f7a93e..378a7faa 100644
--- a/common/flatpak-installation.c
+++ b/common/flatpak-installation.c
@@ -2675,6 +2675,41 @@ flatpak_installation_create_monitor (FlatpakInstallation *self,
                               cancellable, error);
 }
 
+/**
+ * flatpak_installation_get_timestamp:
+ * @self: a #FlatpakInstallation
+ *
+ * Gets the modification time of the installation, based on the file monitored by
+ * flatpak_installation_create_monitor(). This can be used to detect when
+ * applications or runtimes have been installed, uninstalled, or updated, or when
+ * remotes have been added, removed, or modified, to aid cache invalidation.
+ *
+ * Returns: the modification time (seconds since the Unix epoch) of the
+ *   installation configuration, or %G_MAXUINT64 if unavailable
+ *
+ * Since: 1.18.0
+ */
+guint64
+flatpak_installation_get_timestamp (FlatpakInstallation *self)
+{
+  g_autoptr(FlatpakDir) dir = NULL;
+  g_autoptr(GFile) changed_file = NULL;
+  g_autoptr(GFileInfo) info = NULL;
+
+  dir = flatpak_installation_get_dir_maybe_no_repo (self);
+  changed_file = flatpak_dir_get_changed_path (dir);
+
+  info = g_file_query_info (changed_file,
+                            G_FILE_ATTRIBUTE_TIME_MODIFIED,
+                            G_FILE_QUERY_INFO_NONE,
+                            NULL,
+                            NULL);
+  if (info == NULL)
+    return G_MAXUINT64;
+
+  return g_file_info_get_attribute_uint64 (info, G_FILE_ATTRIBUTE_TIME_MODIFIED);
+}
+
 
 /**
  * flatpak_installation_list_remote_related_refs_sync:
diff --git a/common/flatpak-installation.h b/common/flatpak-installation.h
index 5d679d69..74a70a65 100644
--- a/common/flatpak-installation.h
+++ b/common/flatpak-installation.h
@@ -236,6 +236,7 @@ FLATPAK_EXTERN gboolean             flatpak_installation_launch_full (FlatpakIns
 FLATPAK_EXTERN GFileMonitor        *flatpak_installation_create_monitor (FlatpakInstallation *self,
                                                                          GCancellable        *cancellable,
                                                                          GError             **error);
+FLATPAK_EXTERN guint64              flatpak_installation_get_timestamp (FlatpakInstallation *self);
 FLATPAK_EXTERN GPtrArray           *flatpak_installation_list_installed_refs (FlatpakInstallation *self,
                                                                               GCancellable        *cancellable,
                                                                               GError             **error);
diff --git a/doc/reference/flatpak-sections.txt b/doc/reference/flatpak-sections.txt
index 81cfa7c4..1589a708 100644
--- a/doc/reference/flatpak-sections.txt
+++ b/doc/reference/flatpak-sections.txt
@@ -10,6 +10,7 @@ flatpak_installation_new_for_path
 flatpak_installation_get_is_user
 flatpak_installation_get_path
 flatpak_installation_create_monitor
+flatpak_installation_get_timestamp
 flatpak_installation_install
 flatpak_installation_install_full
 flatpak_installation_update
diff --git a/tests/testlibrary.c b/tests/testlibrary.c
index e4c3dcb6..65a4afc8 100644
--- a/tests/testlibrary.c
+++ b/tests/testlibrary.c
@@ -546,6 +546,49 @@ test_list_remotes (void)
   g_assert_cmpuint (remotes2->len, ==, 0);
 }
 
+static void
+test_timestamp (void)
+{
+  g_autoptr(FlatpakInstallation) inst = NULL;
+  g_autoptr(GError) error = NULL;
+  g_autoptr(FlatpakRemote) remote = NULL;
+  guint64 mtime1, mtime2, mtime3;
+
+  inst = flatpak_installation_new_user (NULL, &error);
+  g_assert_no_error (error);
+
+  /* Get initial modification time */
+  mtime1 = flatpak_installation_get_timestamp (inst);
+  g_assert_cmpuint (mtime1, <, G_MAXUINT64);
+
+  /* Wait at least 1 second */
+  sleep (1);
+
+  /* Modification time should stay the same when nothing changes */
+  mtime2 = flatpak_installation_get_timestamp (inst);
+  g_assert_cmpuint (mtime2, ==, mtime1);
+
+  /* Modifying a remote should update the modification time */
+  remote = flatpak_installation_get_remote_by_name (inst, repo_name, NULL, &error);
+  g_assert_no_error (error);
+  g_assert_nonnull (remote);
+
+  flatpak_remote_set_disabled (remote, TRUE);
+  flatpak_installation_modify_remote (inst, remote, NULL, &error);
+  g_assert_no_error (error);
+
+  /* Need to drop caches to see the new modification time */
+  flatpak_installation_drop_caches (inst, NULL, NULL);
+
+  mtime3 = flatpak_installation_get_timestamp (inst);
+  g_assert_cmpuint (mtime3, >, mtime2);
+
+  /* Restore the remote state */
+  flatpak_remote_set_disabled (remote, FALSE);
+  flatpak_installation_modify_remote (inst, remote, NULL, &error);
+  g_assert_no_error (error);
+}
+
 static void
 test_remote_by_name (void)
 {
@@ -5088,6 +5131,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/library/arches", test_arches);
   g_test_add_func ("/library/ref", test_ref);
   g_test_add_func ("/library/list-remotes", test_list_remotes);
+  g_test_add_func ("/library/timestamp", test_timestamp);
   g_test_add_func ("/library/remote-by-name", test_remote_by_name);
   g_test_add_func ("/library/remote", test_remote);
   g_test_add_func ("/library/remote-new", test_remote_new);