Merge pull request #7901 from element-hq/feature/bma/mainThreadBlocking

Avoid blocking the main thread in several places

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

@@ -118,6 +118,7 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.buffer
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.mapNotNull
@@ -320,7 +321,7 @@ class RustMatrixClient(
         override fun onUpdate(profile: UserProfile) {
             val matrixUser = profile.map()
             _userProfile.tryEmit(matrixUser)
-            sessionCoroutineScope.launch {
+            sessionCoroutineScope.launch(sessionDispatcher) {
                 storeUserProfile(matrixUser)
             }
         }
@@ -1013,6 +1014,8 @@ class RustMatrixClient(
                     searchBackfillService.cancelPeriodicSearchBackfill()
                 }
             }
+            // Checking the pending work is a blocking call, do not do it on the main thread
+            .flowOn(sessionDispatcher)
             .launchIn(sessionCoroutineScope)
     }
 }

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/room/JoinedRustRoom.kt

@@ -158,6 +158,7 @@ class JoinedRustRoom(
         inner = innerRoom.threadListService(),
         contentMapper = TimelineEventContentMapper(),
         roomCoroutineScope = roomCoroutineScope,
+        roomDispatcher = roomDispatcher,
     )
 
     override val syncUpdateFlow = flow {

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/room/threads/RustThreadsListService.kt

@@ -17,10 +17,12 @@ import io.element.android.libraries.matrix.api.room.threads.ThreadsListService
 import io.element.android.libraries.matrix.impl.timeline.item.event.TimelineEventContentMapper
 import io.element.android.libraries.matrix.impl.timeline.item.event.map
 import io.element.android.libraries.matrix.impl.util.mxCallbackFlow
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.onStart
@@ -33,6 +35,7 @@ import org.matrix.rustcomponents.sdk.ThreadListService as InnerThreadListService
 class RustThreadsListService(
     private val inner: InnerThreadListService,
     private val roomCoroutineScope: CoroutineScope,
+    private val roomDispatcher: CoroutineDispatcher,
     private val contentMapper: TimelineEventContentMapper = TimelineEventContentMapper(),
 ) : ThreadsListService {
     private var itemSubscriptionJob: Job? = null
@@ -63,6 +66,8 @@ class RustThreadsListService(
                 updated.apply(diff, contentMapper)
                 items.value = updated
             }
+            // Fetching and mapping the items can be costly, do not do it on the main thread
+            .flowOn(roomDispatcher)
             .launchIn(roomCoroutineScope)
     }
 

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClientFactoryTest.kt

@@ -33,7 +33,9 @@ import io.element.android.services.analytics.test.FakeAnalyticsService
 import io.element.android.services.toolbox.test.systemclock.FakeSystemClock
 import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.testCoroutineDispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.runCurrent
 import kotlinx.coroutines.test.runTest
 import org.junit.Test
 import org.matrix.rustcomponents.sdk.Client
@@ -41,6 +43,7 @@ import org.matrix.rustcomponents.sdk.ClientDelegate
 import java.io.File
 import org.matrix.rustcomponents.sdk.SyncService as ClientSyncService
 
+@OptIn(ExperimentalCoroutinesApi::class)
 class RustMatrixClientFactoryTest {
     @Test
     fun test() = runTest {
@@ -51,6 +54,7 @@ class RustMatrixClientFactoryTest {
         val result = sut.create(aSessionData())
 
         assertThat(result.sessionId).isEqualTo(SessionId("@alice:server.org"))
+        runCurrent()
         // 2 workers are scheduled: one for the search backfill and one for the vacuum
         scheduleWorkersLambda.assertions().isCalledExactly(2)
         result.destroy()

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/room/threads/RustThreadsListServiceTest.kt

@@ -18,6 +18,7 @@ import io.element.android.libraries.matrix.test.A_TIMESTAMP
 import io.element.android.libraries.matrix.test.A_USER_ID
 import io.element.android.tests.testutils.lambda.lambdaRecorder
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.runCurrent
 import kotlinx.coroutines.test.runTest
@@ -122,6 +123,7 @@ class RustThreadsListServiceTest {
     ) = RustThreadsListService(
         inner = inner,
         roomCoroutineScope = backgroundScope,
+        roomDispatcher = StandardTestDispatcher(testScheduler),
     )
 
     private fun aRustThreadListUpdate() = ThreadListUpdate.Append(