Timeline : let FocusOnEvent be cancellable and refactor a bit focus states.

changelog.d/2876.misc

@@ -0,0 +1 @@
+Allow cancelling jump to event in timeline.

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineEvents.kt

@@ -23,6 +23,7 @@ sealed interface TimelineEvents {
     data class OnScrollFinished(val firstIndex: Int) : TimelineEvents
     data class FocusOnEvent(val eventId: EventId) : TimelineEvents
     data object ClearFocusRequestState : TimelineEvents
+    data object OnFocusEventRender : TimelineEvents
     data object JumpToLive : TimelineEvents
 
     /**

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenter.kt

@@ -76,9 +76,6 @@ class TimelinePresenter @AssistedInject constructor(
     @Composable
     override fun present(): TimelineState {
         val localScope = rememberCoroutineScope()
-        val focusedEventId: MutableState<EventId?> = rememberSaveable {
-            mutableStateOf(null)
-        }
         val focusRequestState: MutableState<FocusRequestState> = remember {
             mutableStateOf(FocusRequestState.None)
         }
@@ -139,23 +136,16 @@ class TimelinePresenter @AssistedInject constructor(
                     navigator.onEditPollClick(event.pollStartId)
                 }
                 is TimelineEvents.FocusOnEvent -> localScope.launch {
-                    focusedEventId.value = event.eventId
                     if (timelineItemIndexer.isKnown(event.eventId)) {
                         val index = timelineItemIndexer.indexOf(event.eventId)
-                        focusRequestState.value = FocusRequestState.Cached(index)
+                        focusRequestState.value = FocusRequestState.Success(eventId = event.eventId, index = index)
                     } else {
-                        focusRequestState.value = FocusRequestState.Fetching
-                        timelineController.focusOnEvent(event.eventId)
-                            .fold(
-                                onSuccess = {
-                                    focusRequestState.value = FocusRequestState.Fetched
-                                },
-                                onFailure = {
-                                    focusRequestState.value = FocusRequestState.Failure(it)
-                                }
-                            )
+                        focusRequestState.value = FocusRequestState.Loading(eventId = event.eventId)
                     }
                 }
+                is TimelineEvents.OnFocusEventRender -> {
+                    focusRequestState.value = focusRequestState.value.onFocusEventRender()
+                }
                 is TimelineEvents.ClearFocusRequestState -> {
                     focusRequestState.value = FocusRequestState.None
                 }
@@ -165,16 +155,33 @@ class TimelinePresenter @AssistedInject constructor(
             }
         }
 
+        LaunchedEffect(focusRequestState.value) {
+            val currentFocusRequestState = focusRequestState.value
+            if (currentFocusRequestState is FocusRequestState.Loading) {
+                val eventId = currentFocusRequestState.eventId
+                timelineController.focusOnEvent(eventId)
+                    .fold(
+                        onSuccess = {
+                            focusRequestState.value = FocusRequestState.Success(eventId = eventId)
+                        },
+                        onFailure = {
+                            focusRequestState.value = FocusRequestState.Failure(throwable = it)
+                        }
+                    )
+            }
+        }
+
         LaunchedEffect(timelineItems.size) {
             computeNewItemState(timelineItems, prevMostRecentItemId, newEventState)
         }
 
-        LaunchedEffect(timelineItems.size, focusRequestState.value, focusedEventId.value) {
-            val currentFocusedEventId = focusedEventId.value
-            if (focusRequestState.value is FocusRequestState.Fetched && currentFocusedEventId != null) {
-                if (timelineItemIndexer.isKnown(currentFocusedEventId)) {
-                    val index = timelineItemIndexer.indexOf(currentFocusedEventId)
-                    focusRequestState.value = FocusRequestState.Cached(index)
+        LaunchedEffect(timelineItems.size, focusRequestState.value) {
+            val currentFocusRequestState = focusRequestState.value
+            if (currentFocusRequestState is FocusRequestState.Success && !currentFocusRequestState.isIndexed) {
+                val eventId = currentFocusRequestState.eventId
+                if (timelineItemIndexer.isKnown(eventId)) {
+                    val index = timelineItemIndexer.indexOf(eventId)
+                    focusRequestState.value = FocusRequestState.Success(eventId = eventId, index = index)
                 }
             }
         }
@@ -208,7 +215,6 @@ class TimelinePresenter @AssistedInject constructor(
             renderReadReceipts = renderReadReceipts,
             newEventState = newEventState.value,
             isLive = isLive,
-            focusedEventId = focusedEventId.value,
             focusRequestState = focusRequestState.value,
             eventSink = { handleEvents(it) }
         )
@@ -278,3 +284,10 @@ class TimelinePresenter @AssistedInject constructor(
         return null
     }
 }
+
+private fun FocusRequestState.onFocusEventRender(): FocusRequestState {
+    return when (this) {
+        is FocusRequestState.Success -> copy(rendered = true)
+        else -> this
+    }
+}

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineState.kt

@@ -29,20 +29,36 @@ data class TimelineState(
     val renderReadReceipts: Boolean,
     val newEventState: NewEventState,
     val isLive: Boolean,
-    val focusedEventId: EventId?,
     val focusRequestState: FocusRequestState,
     val eventSink: (TimelineEvents) -> Unit,
 ) {
     val hasAnyEvent = timelineItems.any { it is TimelineItem.Event }
+    val focusedEventId = focusRequestState.eventId()
 }
 
 @Immutable
 sealed interface FocusRequestState {
     data object None : FocusRequestState
-    data class Cached(val index: Int) : FocusRequestState
-    data object Fetching : FocusRequestState
-    data object Fetched : FocusRequestState
+    data class Loading(val eventId: EventId) : FocusRequestState
+    data class Success(
+        val eventId: EventId,
+        val index: Int = -1,
+        // This is used to know if the event has been rendered yet.
+        val rendered: Boolean = false,
+    ) : FocusRequestState {
+        val isIndexed
+            get() = index != -1
+    }
+
     data class Failure(val throwable: Throwable) : FocusRequestState
+
+    fun eventId(): EventId? {
+        return when (this) {
+            is Loading -> eventId
+            is Success -> eventId
+            else -> null
+        }
+    }
 }
 
 @Immutable

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineStateProvider.kt

@@ -51,16 +51,23 @@ fun aTimelineState(
     focusedEventIndex: Int = -1,
     isLive: Boolean = true,
     eventSink: (TimelineEvents) -> Unit = {},
-) = TimelineState(
-    timelineItems = timelineItems,
-    timelineRoomInfo = timelineRoomInfo,
-    renderReadReceipts = renderReadReceipts,
-    newEventState = NewEventState.None,
-    isLive = isLive,
-    focusedEventId = timelineItems.filterIsInstance<TimelineItem.Event>().getOrNull(focusedEventIndex)?.eventId,
-    focusRequestState = FocusRequestState.None,
-    eventSink = eventSink,
-)
+): TimelineState {
+    val focusedEventId = timelineItems.filterIsInstance<TimelineItem.Event>().getOrNull(focusedEventIndex)?.eventId
+    val focusRequestState = if (focusedEventId != null) {
+        FocusRequestState.Success(focusedEventId, focusedEventIndex)
+    } else {
+        FocusRequestState.None
+    }
+    return TimelineState(
+        timelineItems = timelineItems,
+        timelineRoomInfo = timelineRoomInfo,
+        renderReadReceipts = renderReadReceipts,
+        newEventState = NewEventState.None,
+        isLive = isLive,
+        focusRequestState = focusRequestState,
+        eventSink = eventSink,
+    )
+}
 
 internal fun aTimelineItemList(content: TimelineItemEventContent): ImmutableList<TimelineItem> {
     return persistentListOf(

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineView.kt

@@ -100,6 +100,14 @@ fun TimelineView(
         state.eventSink(TimelineEvents.OnScrollFinished(firstVisibleIndex))
     }
 
+    fun onFocusEventRender() {
+        state.eventSink(TimelineEvents.OnFocusEventRender)
+    }
+
+    fun onJumpToLive() {
+        state.eventSink(TimelineEvents.JumpToLive)
+    }
+
     val context = LocalContext.current
     val lazyListState = rememberLazyListState()
     // Disable reverse layout when TalkBack is enabled to avoid incorrect ordering issues seen in the current Compose UI version
@@ -167,8 +175,8 @@ fun TimelineView(
                 isLive = state.isLive,
                 focusRequestState = state.focusRequestState,
                 onScrollFinishAt = ::onScrollFinishAt,
-                onClearFocusRequestState = ::clearFocusRequestState,
-                onJumpToLive = { state.eventSink(TimelineEvents.JumpToLive) },
+                onJumpToLive = ::onJumpToLive,
+                onFocusEventRender = ::onFocusEventRender,
             )
         }
     }
@@ -182,9 +190,9 @@ private fun BoxScope.TimelineScrollHelper(
     isLive: Boolean,
     forceJumpToBottomVisibility: Boolean,
     focusRequestState: FocusRequestState,
-    onClearFocusRequestState: () -> Unit,
     onScrollFinishAt: (Int) -> Unit,
     onJumpToLive: () -> Unit,
+    onFocusEventRender: () -> Unit,
 ) {
     val coroutineScope = rememberCoroutineScope()
     val isScrollFinished by remember { derivedStateOf { !lazyListState.isScrollInProgress } }
@@ -212,15 +220,15 @@ private fun BoxScope.TimelineScrollHelper(
         }
     }
 
-    val latestOnClearFocusRequestState by rememberUpdatedState(onClearFocusRequestState)
+    val latestOnFocusEventRender by rememberUpdatedState(onFocusEventRender)
     LaunchedEffect(focusRequestState) {
-        if (focusRequestState is FocusRequestState.Cached) {
+        if (focusRequestState is FocusRequestState.Success && focusRequestState.isIndexed) {
             if (abs(lazyListState.firstVisibleItemIndex - focusRequestState.index) < 10) {
                 lazyListState.animateScrollToItem(focusRequestState.index)
             } else {
                 lazyListState.scrollToItem(focusRequestState.index)
             }
-            latestOnClearFocusRequestState()
+            latestOnFocusEventRender()
         }
     }
 
@@ -243,8 +251,8 @@ private fun BoxScope.TimelineScrollHelper(
         // Use inverse of canAutoScroll otherwise we might briefly see the before the scroll animation is triggered
         isVisible = !canAutoScroll || forceJumpToBottomVisibility || !isLive,
         modifier = Modifier
-                .align(Alignment.BottomEnd)
-                .padding(end = 24.dp, bottom = 12.dp),
+            .align(Alignment.BottomEnd)
+            .padding(end = 24.dp, bottom = 12.dp),
         onClick = { jumpToBottom() },
     )
 }
@@ -271,8 +279,8 @@ private fun JumpToBottomButton(
         ) {
             Icon(
                 modifier = Modifier
-                        .size(24.dp)
-                        .rotate(90f),
+                    .size(24.dp)
+                    .rotate(90f),
                 imageVector = CompoundIcons.ArrowRight(),
                 contentDescription = stringResource(id = CommonStrings.a11y_jump_to_bottom)
             )

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/focus/FocusRequestStateProvider.kt

@@ -24,7 +24,9 @@ import io.element.android.libraries.matrix.api.room.errors.FocusEventException
 open class FocusRequestStateProvider : PreviewParameterProvider<FocusRequestState> {
     override val values: Sequence<FocusRequestState>
         get() = sequenceOf(
-            FocusRequestState.Fetching,
+            FocusRequestState.Loading(
+                eventId = EventId("\$anEventId"),
+            ),
             FocusRequestState.Failure(
                 FocusEventException.EventNotFound(
                     eventId = EventId("\$anEventId"),

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/focus/FocusRequestStateView.kt

@@ -49,7 +49,7 @@ fun FocusRequestStateView(
                 modifier = modifier,
             )
         }
-        FocusRequestState.Fetching -> {
+        is FocusRequestState.Loading -> {
             ProgressDialog(
                 modifier = modifier,
                 properties = DialogProperties(dismissOnBackPress = true, dismissOnClickOutside = true),

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenterTest.kt

@@ -495,11 +495,11 @@ private const val FAKE_UNIQUE_ID_2 = "FAKE_UNIQUE_ID_2"
             initialState.eventSink.invoke(TimelineEvents.FocusOnEvent(AN_EVENT_ID))
             awaitItem().also { state ->
                 assertThat(state.focusedEventId).isEqualTo(AN_EVENT_ID)
-                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Fetching)
+                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Loading(AN_EVENT_ID))
             }
             skipItems(2)
             awaitItem().also { state ->
-                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Fetched)
+                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Success(AN_EVENT_ID))
                 assertThat(state.timelineItems).isNotEmpty()
             }
             initialState.eventSink.invoke(TimelineEvents.JumpToLive)
@@ -539,7 +539,7 @@ private const val FAKE_UNIQUE_ID_2 = "FAKE_UNIQUE_ID_2"
             initialState.eventSink.invoke(TimelineEvents.FocusOnEvent(AN_EVENT_ID))
             awaitItem().also { state ->
                 assertThat(state.focusedEventId).isEqualTo(AN_EVENT_ID)
-                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Cached(0))
+                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Success(AN_EVENT_ID, 0))
             }
         }
     }
@@ -562,7 +562,7 @@ private const val FAKE_UNIQUE_ID_2 = "FAKE_UNIQUE_ID_2"
             initialState.eventSink(TimelineEvents.FocusOnEvent(AN_EVENT_ID))
             awaitItem().also { state ->
                 assertThat(state.focusedEventId).isEqualTo(AN_EVENT_ID)
-                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Fetching)
+                assertThat(state.focusRequestState).isEqualTo(FocusRequestState.Loading(AN_EVENT_ID))
             }
             awaitItem().also { state ->
                 assertThat(state.focusRequestState).isInstanceOf(FocusRequestState.Failure::class.java)

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

@@ -87,6 +87,7 @@ import org.matrix.rustcomponents.sdk.use
 import timber.log.Timber
 import uniffi.matrix_sdk.RoomPowerLevelChanges
 import java.io.File
+import kotlin.coroutines.cancellation.CancellationException
 import org.matrix.rustcomponents.sdk.Room as InnerRoom
 import org.matrix.rustcomponents.sdk.Timeline as InnerTimeline
 
@@ -183,6 +184,10 @@ class RustMatrixRoom(
             }
         }.mapFailure {
             it.toFocusEventException()
+        }.onFailure {
+            if (it is CancellationException) {
+                throw it
+            }
         }
     }