Ensure the sync is started when receiving a Push, to ensure that the encryption loop is running.

Fixes notification with endecrypted content (#1178)

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/sync/StartSyncReason.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.sync
+
+import io.element.android.libraries.matrix.api.core.EventId
+import io.element.android.libraries.matrix.api.core.RoomId
+
+sealed interface StartSyncReason {
+    data object AppInForeground : StartSyncReason
+    data class Notification(val roomId: RoomId, val eventId: EventId) : StartSyncReason
+}

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/sync/SyncService.kt

@@ -22,12 +22,12 @@ interface SyncService {
     /**
      * Tries to start the sync. If already syncing it has no effect.
      */
-    suspend fun startSync(): Result<Unit>
+    suspend fun startSync(reason: StartSyncReason): Result<Unit>
 
     /**
      * Tries to stop the sync. If service is not syncing it has no effect.
      */
-    suspend fun stopSync(): Result<Unit>
+    suspend fun stopSync(reason: StartSyncReason): Result<Unit>
 
     /**
      * Flow of [SyncState]. Will be updated as soon as the current [SyncState] changes.

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/sync/RustSyncService.kt

@@ -16,6 +16,7 @@
 
 package io.element.android.libraries.matrix.impl.sync
 
+import io.element.android.libraries.matrix.api.sync.StartSyncReason
 import io.element.android.libraries.matrix.api.sync.SyncService
 import io.element.android.libraries.matrix.api.sync.SyncState
 import kotlinx.coroutines.CoroutineScope
@@ -25,6 +26,8 @@ import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import org.matrix.rustcomponents.sdk.SyncServiceInterface
 import org.matrix.rustcomponents.sdk.SyncServiceState
 import timber.log.Timber
@@ -33,19 +36,36 @@ class RustSyncService(
     private val innerSyncService: SyncServiceInterface,
     sessionCoroutineScope: CoroutineScope
 ) : SyncService {
+    private val mutex = Mutex()
+    private val startSyncReasonSet = mutableSetOf<StartSyncReason>()
 
-    override suspend fun startSync() = runCatching {
-        Timber.i("Start sync")
-        innerSyncService.start()
-    }.onFailure {
-        Timber.d("Start sync failed: $it")
+    override suspend fun startSync(reason: StartSyncReason): Result<Unit> {
+        return mutex.withLock {
+            startSyncReasonSet.add(reason)
+            runCatching {
+                Timber.d("Start sync")
+                innerSyncService.start()
+            }.onFailure {
+                Timber.e("Start sync failed: $it")
+            }
+        }
     }
 
-    override suspend fun stopSync() = runCatching {
-        Timber.i("Stop sync")
-        innerSyncService.stop()
-    }.onFailure {
-        Timber.d("Stop sync failed: $it")
+    override suspend fun stopSync(reason: StartSyncReason): Result<Unit> {
+        return mutex.withLock {
+            startSyncReasonSet.remove(reason)
+            if (startSyncReasonSet.isEmpty()) {
+                runCatching {
+                    Timber.d("Stop sync")
+                    innerSyncService.stop()
+                }.onFailure {
+                    Timber.e("Stop sync failed: $it")
+                }
+            } else {
+                Timber.d("Stop sync skipped, still $startSyncReasonSet")
+                Result.success(Unit)
+            }
+        }
     }
 
     override val syncState: StateFlow<SyncState> =

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/sync/FakeSyncService.kt

@@ -16,6 +16,7 @@
 
 package io.element.android.libraries.matrix.test.sync
 
+import io.element.android.libraries.matrix.api.sync.StartSyncReason
 import io.element.android.libraries.matrix.api.sync.SyncService
 import io.element.android.libraries.matrix.api.sync.SyncState
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -29,12 +30,12 @@ class FakeSyncService : SyncService {
         syncStateFlow.value = SyncState.Error
     }
 
-    override suspend fun startSync(): Result<Unit> {
+    override suspend fun startSync(reason: StartSyncReason): Result<Unit> {
         syncStateFlow.value = SyncState.Running
         return Result.success(Unit)
     }
 
-    override suspend fun stopSync(): Result<Unit> {
+    override suspend fun stopSync(reason: StartSyncReason): Result<Unit> {
         syncStateFlow.value = SyncState.Terminated
         return Result.success(Unit)
     }