feat(indexeddb): Add support for key backup v1

crates/matrix-sdk-indexeddb/src/cryptostore.rs

@@ -65,6 +65,11 @@ mod KEYS {
     pub const STORE_CIPHER: &str = "store_cipher";
     pub const ACCOUNT: &str = "account";
     pub const PRIVATE_IDENTITY: &str = "private_identity";
+
+    // BACKUP v1
+    pub const BACKUP_KEYS: &str = "backup_keys";
+    pub const BACKUP_KEY_V1: &str = "backup_key_v1";
+    pub const RECOVERY_KEY_V1: &str = "recovery_key_v1";
 }
 
 /// An in-memory only store that will forget all the E2EE key once it's dropped.
@@ -159,6 +164,8 @@ impl IndexeddbStore {
                 db.create_object_store(KEYS::OUTGOING_SECRET_REQUESTS)?;
                 db.create_object_store(KEYS::UNSENT_SECRET_REQUESTS)?;
                 db.create_object_store(KEYS::SECRET_REQUESTS_BY_INFO)?;
+
+                db.create_object_store(KEYS::BACKUP_KEYS)?;
             }
             Ok(())
         }));
@@ -270,6 +277,7 @@ impl IndexeddbStore {
     async fn save_changes(&self, changes: Changes) -> Result<()> {
         let mut stores: Vec<&str> = [
             (changes.account.is_some() || changes.private_identity.is_some(), KEYS::CORE),
+            (changes.recovery_key.is_some() || changes.backup_version.is_some(), KEYS::BACKUP_KEYS),
             (!changes.sessions.is_empty(), KEYS::SESSION),
             (
                 !changes.devices.new.is_empty()
@@ -311,6 +319,9 @@ impl IndexeddbStore {
         let private_identity_pickle =
             if let Some(i) = changes.private_identity { Some(i.pickle().await?) } else { None };
 
+        let recovery_key_pickle = changes.recovery_key;
+        let backup_version = changes.backup_version;
+
         if let Some(a) = &account_pickle {
             tx.object_store(KEYS::CORE)?
                 .put_key_val(&JsValue::from_str(KEYS::ACCOUNT), &self.serialize_value(&a)?)?;
@@ -323,6 +334,17 @@ impl IndexeddbStore {
             )?;
         }
 
+        if let Some(a) = &recovery_key_pickle {
+            tx.object_store(KEYS::BACKUP_KEYS)?
+                .put_key_val(&JsValue::from_str(KEYS::RECOVERY_KEY_V1), &self.serialize_value(&a)?)?;
+        }
+
+        if let Some(a) = &backup_version {
+            tx.object_store(KEYS::BACKUP_KEYS)?
+                .put_key_val(&JsValue::from_str(KEYS::BACKUP_KEY_V1), &self.serialize_value(&a)?)?;
+        }
+
+
         if !changes.sessions.is_empty() {
             let sessions = tx.object_store(KEYS::SESSION)?;
 
@@ -834,6 +856,34 @@ impl IndexeddbStore {
 
         tx.await.into_result().map_err(|e| e.into())
     }
+
+    async fn load_backup_keys(&self) -> Result<BackupKeys> {
+        let key = {
+            let tx = self
+                .inner
+                .transaction_on_one_with_mode(
+                    KEYS::BACKUP_KEYS,
+                    IdbTransactionMode::Readonly,
+                )?;
+            let store = tx.object_store(KEYS::BACKUP_KEYS)?;
+
+            let backup_version = store
+                .get(&JsValue::from_str(KEYS::BACKUP_KEY_V1))?
+                .await?
+                .map(|i| self.deserialize_value(i))
+                .transpose()?;
+
+            let recovery_key = store
+                .get(&JsValue::from_str(KEYS::RECOVERY_KEY_V1))?
+                .await?
+                .map(|i| self.deserialize_value(i))
+                .transpose()?;
+
+            BackupKeys { backup_version, recovery_key }
+        };
+
+        Ok(key)
+    }
 }
 
 #[async_trait(?Send)]
@@ -924,9 +974,8 @@ impl CryptoStore for IndexeddbStore {
         self.users_for_key_query()
     }
 
-    #[allow(clippy::todo)]
     async fn load_backup_keys(&self) -> Result<BackupKeys, CryptoStoreError> {
-        todo!()
+        self.load_backup_keys().await.map_err(|e| e.into())
     }
 
     async fn update_tracked_user(