Timeline : reactivate loaders and get off the main thread

app/build.gradle

@@ -58,7 +58,7 @@ android {
 
 dependencies {
 
-    def epoxy_version = "3.0.0"
+    def epoxy_version = "3.3.0"
     def arrow_version = "0.8.2"
     def coroutines_version = "1.0.1"
     def markwon_version = '3.0.0-SNAPSHOT'
@@ -77,9 +77,6 @@ dependencies {
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
     implementation 'androidx.core:core-ktx:1.0.1'
 
-    // Paging
-    implementation 'androidx.paging:paging-runtime:2.0.0'
-
     implementation 'com.jakewharton.threetenabp:threetenabp:1.1.1'
     implementation 'com.jakewharton.timber:timber:4.7.1'
     implementation 'com.facebook.stetho:stetho:1.5.0'

app/src/main/java/im/vector/riotredesign/Riot.kt

@@ -19,6 +19,8 @@ package im.vector.riotredesign
 import android.app.Application
 import android.content.Context
 import androidx.multidex.MultiDex
+import com.airbnb.epoxy.EpoxyAsyncUtil
+import com.airbnb.epoxy.EpoxyController
 import com.facebook.stetho.Stetho
 import com.github.piasy.biv.BigImageViewer
 import com.github.piasy.biv.loader.glide.GlideImageLoader
@@ -41,6 +43,8 @@ class Riot : Application() {
         }
         AndroidThreeTen.init(this)
         BigImageViewer.initialize(GlideImageLoader.with(applicationContext))
+        EpoxyController.defaultDiffingHandler = EpoxyAsyncUtil.getAsyncBackgroundHandler()
+        EpoxyController.defaultModelBuildingHandler = EpoxyAsyncUtil.getAsyncBackgroundHandler()
         val appModule = AppModule(applicationContext).definition
         val homeModule = HomeModule().definition
         startKoin(listOf(appModule, homeModule), logger = EmptyLogger())

app/src/main/java/im/vector/riotredesign/features/home/room/detail/RoomDetailActions.kt

@@ -16,6 +16,7 @@
 
 package im.vector.riotredesign.features.home.room.detail
 
+import im.vector.matrix.android.api.session.room.timeline.Timeline
 import im.vector.matrix.android.api.session.room.timeline.TimelineEvent
 
 sealed class RoomDetailActions {
@@ -23,6 +24,6 @@ sealed class RoomDetailActions {
     data class SendMessage(val text: String) : RoomDetailActions()
     object IsDisplayed : RoomDetailActions()
     data class EventDisplayed(val event: TimelineEvent) : RoomDetailActions()
-    object LoadMore: RoomDetailActions()
+    data class LoadMore(val direction: Timeline.Direction) : RoomDetailActions()
 
 }

app/src/main/java/im/vector/riotredesign/features/home/room/detail/RoomDetailFragment.kt

@@ -25,6 +25,7 @@ import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.airbnb.epoxy.EpoxyVisibilityTracker
 import com.airbnb.mvrx.fragmentViewModel
+import im.vector.matrix.android.api.session.room.timeline.Timeline
 import im.vector.matrix.android.api.session.room.timeline.TimelineEvent
 import im.vector.riotredesign.R
 import im.vector.riotredesign.core.epoxy.LayoutManagerStateRestorer
@@ -110,9 +111,14 @@ class RoomDetailFragment : RiotFragment(), TimelineEventController.Callback {
             it.dispatchTo(stateRestorer)
             it.dispatchTo(scrollOnNewMessageCallback)
         }
-        recyclerView.addOnScrollListener(object : EndlessRecyclerViewScrollListener(layoutManager, EndlessRecyclerViewScrollListener.LoadOnScrollDirection.BOTTOM) {
+        recyclerView.addOnScrollListener(object : EndlessRecyclerViewScrollListener(layoutManager, Timeline.Direction.BACKWARDS) {
-            override fun onLoadMore(page: Int, totalItemsCount: Int) {
+            override fun onLoadMore() {
-                roomDetailViewModel.process(RoomDetailActions.LoadMore)
+                roomDetailViewModel.process(RoomDetailActions.LoadMore(Timeline.Direction.BACKWARDS))
+            }
+        })
+        recyclerView.addOnScrollListener(object : EndlessRecyclerViewScrollListener(layoutManager, Timeline.Direction.FORWARDS) {
+            override fun onLoadMore() {
+                roomDetailViewModel.process(RoomDetailActions.LoadMore(Timeline.Direction.FORWARDS))
             }
         })
         recyclerView.setController(timelineEventController)

app/src/main/java/im/vector/riotredesign/features/home/room/detail/RoomDetailViewModel.kt

@@ -22,12 +22,12 @@ import com.jakewharton.rxrelay2.BehaviorRelay
 import im.vector.matrix.android.api.MatrixCallback
 import im.vector.matrix.android.api.session.Session
 import im.vector.matrix.android.api.session.events.model.Event
-import im.vector.matrix.android.api.session.room.timeline.Timeline
 import im.vector.matrix.rx.rx
 import im.vector.riotredesign.core.platform.RiotViewModel
 import im.vector.riotredesign.features.home.room.VisibleRoomStore
 import io.reactivex.rxkotlin.subscribeBy
 import org.koin.android.ext.android.get
+import timber.log.Timber
 import java.util.concurrent.TimeUnit
 
 class RoomDetailViewModel(initialState: RoomDetailViewState,
@@ -64,7 +64,7 @@ class RoomDetailViewModel(initialState: RoomDetailViewState,
             is RoomDetailActions.SendMessage    -> handleSendMessage(action)
             is RoomDetailActions.IsDisplayed    -> handleIsDisplayed()
             is RoomDetailActions.EventDisplayed -> handleEventDisplayed(action)
-            is RoomDetailActions.LoadMore       -> timeline.paginate(Timeline.Direction.BACKWARDS, 50)
+            is RoomDetailActions.LoadMore       -> handleLoadMore(action)
         }
     }
 
@@ -82,6 +82,10 @@ class RoomDetailViewModel(initialState: RoomDetailViewState,
         visibleRoomHolder.post(roomId)
     }
 
+    private fun handleLoadMore(action: RoomDetailActions.LoadMore) {
+        timeline.paginate(action.direction, 50)
+    }
+
     private fun observeDisplayedEvents() {
         // We are buffering scroll events for one second
         // and keep the most recent one to set the read receipt on.
@@ -100,13 +104,14 @@ class RoomDetailViewModel(initialState: RoomDetailViewState,
     private fun observeRoomSummary() {
         room.rx().liveRoomSummary()
                 .execute { async ->
+                    Timber.v("Room summary updated: $async")
                     copy(asyncRoomSummary = async)
                 }
     }
 
     override fun onCleared() {
-        super.onCleared()
         timeline.dispose()
+        super.onCleared()
     }
 
 }

app/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/TimelineEventController.kt

@@ -16,19 +16,21 @@
 
 package im.vector.riotredesign.features.home.room.detail.timeline
 
+import android.os.Handler
 import android.view.View
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListUpdateCallback
 import androidx.recyclerview.widget.RecyclerView
-import com.airbnb.epoxy.EpoxyAsyncUtil
 import com.airbnb.epoxy.EpoxyController
 import com.airbnb.epoxy.EpoxyModel
 import com.airbnb.epoxy.VisibilityState
 import im.vector.matrix.android.api.session.room.timeline.Timeline
 import im.vector.matrix.android.api.session.room.timeline.TimelineEvent
+import im.vector.riotredesign.core.epoxy.LoadingItemModel_
 import im.vector.riotredesign.core.epoxy.RiotEpoxyModel
 import im.vector.riotredesign.core.extensions.localDateTime
 import im.vector.riotredesign.features.home.room.detail.timeline.factory.TimelineItemFactory
+import im.vector.riotredesign.features.home.room.detail.timeline.helper.TimelineAsyncHelper
 import im.vector.riotredesign.features.home.room.detail.timeline.helper.TimelineDateFormatter
 import im.vector.riotredesign.features.home.room.detail.timeline.helper.TimelineEventDiffUtilCallback
 import im.vector.riotredesign.features.home.room.detail.timeline.helper.TimelineMediaSizeProvider
@@ -37,20 +39,16 @@ import im.vector.riotredesign.features.media.MediaContentRenderer
 
 class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
                               private val timelineItemFactory: TimelineItemFactory,
-                              private val timelineMediaSizeProvider: TimelineMediaSizeProvider
+                              private val timelineMediaSizeProvider: TimelineMediaSizeProvider,
-) : EpoxyController(
+                              private val backgroundHandler: Handler = TimelineAsyncHelper.getBackgroundHandler()
-        EpoxyAsyncUtil.getAsyncBackgroundHandler(),
+) : EpoxyController(backgroundHandler, backgroundHandler), Timeline.Listener {
-        EpoxyAsyncUtil.getAsyncBackgroundHandler()
-), Timeline.Listener {
 
     private val modelCache = arrayListOf<List<EpoxyModel<*>>>()
     private var currentSnapshot: List<TimelineEvent> = emptyList()
 
-    override fun onUpdated(snapshot: List<TimelineEvent>) {
-        submitSnapshot(snapshot)
-    }
-
     private val listUpdateCallback = object : ListUpdateCallback {
+
+        @Synchronized
         override fun onChanged(position: Int, count: Int, payload: Any?) {
             (position until (position + count)).forEach {
                 modelCache[it] = emptyList()
@@ -62,7 +60,8 @@ class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
             //no-op
         }
 
-        override fun onInserted(position: Int, count: Int) {
+        @Synchronized
+        override fun onInserted(position: Int, count: Int) = synchronized(modelCache) {
             if (modelCache.isNotEmpty() && position == modelCache.size) {
                 modelCache[position - 1] = emptyList()
             }
@@ -78,10 +77,6 @@ class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
 
     }
 
-    private var isLoadingForward: Boolean = false
-    private var isLoadingBackward: Boolean = false
-    private var hasReachedEnd: Boolean = true
-
     private var timeline: Timeline? = null
     var callback: Callback? = null
 
@@ -89,7 +84,6 @@ class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
         if (this.timeline != timeline) {
             this.timeline = timeline
             this.timeline?.listener = this
-            submitSnapshot(timeline?.snapshot() ?: emptyList())
         }
     }
 
@@ -99,9 +93,25 @@ class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
     }
 
     override fun buildModels() {
+        LoadingItemModel_()
+                .id("forward_loading_item")
+                .addWhen(Timeline.Direction.FORWARDS)
+
         add(getModels())
+
+        LoadingItemModel_()
+                .id("backward_loading_item")
+                .addWhen(Timeline.Direction.BACKWARDS)
     }
 
+    private fun LoadingItemModel_.addWhen(direction: Timeline.Direction) {
+        val shouldAdd = timeline?.let {
+            it.hasMoreToLoad(direction) || !it.hasReachedEnd(direction)
+        } ?: false
+        addIf(shouldAdd, this@TimelineEventController)
+    }
+
+    @Synchronized
     private fun getModels(): List<EpoxyModel<*>> {
         (0 until modelCache.size).forEach { position ->
             if (modelCache[position].isEmpty()) {
@@ -133,8 +143,14 @@ class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
         return epoxyModels
     }
 
+    // Timeline.LISTENER ***************************************************************************
+
+    override fun onUpdated(snapshot: List<TimelineEvent>) {
+        submitSnapshot(snapshot)
+    }
+
     private fun submitSnapshot(newSnapshot: List<TimelineEvent>) {
-        EpoxyAsyncUtil.getAsyncBackgroundHandler().post {
+        backgroundHandler.post {
             val diffCallback = TimelineEventDiffUtilCallback(currentSnapshot, newSnapshot)
             currentSnapshot = newSnapshot
             val diffResult = DiffUtil.calculateDiff(diffCallback)
@@ -142,6 +158,7 @@ class TimelineEventController(private val dateFormatter: TimelineDateFormatter,
         }
     }
 
+
     interface Callback {
         fun onEventVisible(event: TimelineEvent)
         fun onUrlClicked(url: String)

app/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/helper/EndlessRecyclerViewScrollListener.java

@@ -19,26 +19,24 @@ package im.vector.riotredesign.features.home.room.detail.timeline.helper;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
+import im.vector.matrix.android.api.session.room.timeline.Timeline;
 
-// Todo rework that, it has been copy/paste at the moment
 public abstract class EndlessRecyclerViewScrollListener extends RecyclerView.OnScrollListener {
     // Sets the starting page index
     private static final int startingPageIndex = 0;
     // The minimum amount of items to have below your current scroll position
     // before loading more.
-    private int visibleThreshold = 30;
+    private int visibleThreshold = 50;
-    // The current offset index of data you have loaded
-    private int currentPage = 0;
     // The total number of items in the dataset after the last load
     private int previousTotalItemCount = 0;
     // True if we are still waiting for the last set of data to load.
     private boolean loading = true;
     private LinearLayoutManager mLayoutManager;
-    private LoadOnScrollDirection mDirection;
+    private Timeline.Direction mDirection;
 
-    public EndlessRecyclerViewScrollListener(LinearLayoutManager layoutManager, LoadOnScrollDirection direction) {
+    public EndlessRecyclerViewScrollListener(LinearLayoutManager layoutManager, Timeline.Direction direction) {
         this.mLayoutManager = layoutManager;
-        mDirection = direction;
+        this.mDirection = direction;
     }
 
 
@@ -55,11 +53,10 @@ public abstract class EndlessRecyclerViewScrollListener extends RecyclerView.OnS
         firstVisibleItemPosition = mLayoutManager.findFirstVisibleItemPosition();
 
         switch (mDirection) {
-            case BOTTOM:
+            case BACKWARDS:
                 // If the total item count is zero and the previous isn't, assume the
                 // list is invalidated and should be reset back to initial state
                 if (totalItemCount < previousTotalItemCount) {
-                    this.currentPage = startingPageIndex;
                     this.previousTotalItemCount = totalItemCount;
                     if (totalItemCount == 0) {
                         this.loading = true;
@@ -78,16 +75,14 @@ public abstract class EndlessRecyclerViewScrollListener extends RecyclerView.OnS
                 // If we do need to reload some more data, we execute onLoadMore to fetch the data.
                 // threshold should reflect how many total columns there are too
                 if (!loading && (lastVisibleItemPosition + visibleThreshold) > totalItemCount) {
-                    currentPage++;
+                    onLoadMore();
-                    onLoadMore(currentPage, totalItemCount);
                     loading = true;
                 }
                 break;
-            case TOP:
+            case FORWARDS:
                 // If the total item count is zero and the previous isn't, assume the
                 // list is invalidated and should be reset back to initial state
                 if (totalItemCount < previousTotalItemCount) {
-                    this.currentPage = startingPageIndex;
                     this.previousTotalItemCount = totalItemCount;
                     if (totalItemCount == 0) {
                         this.loading = true;
@@ -106,42 +101,14 @@ public abstract class EndlessRecyclerViewScrollListener extends RecyclerView.OnS
                 // If we do need to reload some more data, we execute onLoadMore to fetch the data.
                 // threshold should reflect how many total columns there are too
                 if (!loading && firstVisibleItemPosition < visibleThreshold) {
-                    currentPage++;
+                    onLoadMore();
-                    onLoadMore(currentPage, totalItemCount);
                     loading = true;
                 }
                 break;
         }
     }
 
-    private int getLastVisibleItem(int[] lastVisibleItemPositions) {
-        int maxSize = 0;
-        for (int i = 0; i < lastVisibleItemPositions.length; i++) {
-            if (i == 0) {
-                maxSize = lastVisibleItemPositions[i];
-            } else if (lastVisibleItemPositions[i] > maxSize) {
-                maxSize = lastVisibleItemPositions[i];
-            }
-        }
-        return maxSize;
-    }
-
-    private int getFirstVisibleItem(int[] firstVisibleItemPositions) {
-        int maxSize = 0;
-        for (int i = 0; i < firstVisibleItemPositions.length; i++) {
-            if (i == 0) {
-                maxSize = firstVisibleItemPositions[i];
-            } else if (firstVisibleItemPositions[i] > maxSize) {
-                maxSize = firstVisibleItemPositions[i];
-            }
-        }
-        return maxSize;
-    }
-
     // Defines the process for actually loading more data based on page
-    public abstract void onLoadMore(int page, int totalItemsCount);
+    public abstract void onLoadMore();
 
-    public enum LoadOnScrollDirection {
-        TOP, BOTTOM
-    }
 }

app/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/helper/TimelineAsyncHelper.kt

@@ -0,0 +1,47 @@
+/*
+ *
+ *  * Copyright 2019 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 im.vector.riotredesign.features.home.room.detail.timeline.helper
+
+import android.os.Handler
+import android.os.HandlerThread
+
+private const val THREAD_NAME = "Timeline_Building_Thread"
+
+object TimelineAsyncHelper {
+
+    private var backgroundHandlerThread: HandlerThread? = null
+    private var backgroundHandler: Handler? = null
+
+    fun getBackgroundHandler(): Handler {
+        if (backgroundHandler != null) {
+            backgroundHandler?.removeCallbacksAndMessages(null)
+        }
+        if (backgroundHandlerThread != null) {
+            backgroundHandlerThread?.quit()
+        }
+        val handlerThread = HandlerThread(THREAD_NAME)
+                .also {
+                    backgroundHandlerThread = it
+                    it.start()
+                }
+        val looper = handlerThread.looper
+        return Handler(looper).also { backgroundHandler = it }
+    }
+
+}

matrix-sdk-android/build.gradle

@@ -76,9 +76,6 @@ dependencies {
     implementation 'com.github.Zhuinden:realm-monarchy:0.5.1'
     kapt 'dk.ilios:realmfieldnameshelper:1.1.1'
 
-    // Paging
-    implementation 'androidx.paging:paging-runtime:2.0.0'
-
     // Work
     implementation "android.arch.work:work-runtime-ktx:1.0.0-beta02"
 

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/session/room/timeline/ChunkEntityTest.kt

@@ -134,13 +134,13 @@ internal class ChunkEntityTest : InstrumentedTest {
             val chunk2: ChunkEntity = realm.createObject()
             val eventsForChunk1 = createFakeListOfEvents(30)
             val eventsForChunk2 = eventsForChunk1 + createFakeListOfEvents(10)
-            chunk1.isLast = true
+            chunk1.isLastForward = true
-            chunk2.isLast = false
+            chunk2.isLastForward = false
             chunk1.addAll("roomId", eventsForChunk1, PaginationDirection.FORWARDS)
             chunk2.addAll("roomId", eventsForChunk2, PaginationDirection.BACKWARDS)
             chunk1.merge("roomId", chunk2, PaginationDirection.BACKWARDS)
             chunk1.events.size shouldEqual 40
-            chunk1.isLast.shouldBeTrue()
+            chunk1.isLastForward.shouldBeTrue()
         }
     }
 

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/session/room/timeline/FakeGetContextOfEventTask.kt

@@ -25,7 +25,7 @@ import kotlin.random.Random
 
 internal class FakeGetContextOfEventTask(private val tokenChunkEventPersistor: TokenChunkEventPersistor) : GetContextOfEventTask {
 
-    override fun execute(params: GetContextOfEventTask.Params): Try<TokenChunkEvent> {
+    override fun execute(params: GetContextOfEventTask.Params): Try<TokenChunkEventPersistor.Result> {
         val fakeEvents = RoomDataHelper.createFakeListOfEvents(30)
         val tokenChunkEvent = FakeTokenChunkEvent(
                 Random.nextLong(System.currentTimeMillis()).toString(),
@@ -33,7 +33,6 @@ internal class FakeGetContextOfEventTask(private val tokenChunkEventPersistor: T
                 fakeEvents
         )
         return tokenChunkEventPersistor.insertInDb(tokenChunkEvent, params.roomId, PaginationDirection.BACKWARDS)
-                .map { tokenChunkEvent }
     }
 
 

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/session/room/timeline/FakePaginationTask.kt

@@ -18,17 +18,15 @@ package im.vector.matrix.android.session.room.timeline
 
 import arrow.core.Try
 import im.vector.matrix.android.internal.session.room.timeline.PaginationTask
-import im.vector.matrix.android.internal.session.room.timeline.TokenChunkEvent
 import im.vector.matrix.android.internal.session.room.timeline.TokenChunkEventPersistor
 import kotlin.random.Random
 
 internal class FakePaginationTask(private val tokenChunkEventPersistor: TokenChunkEventPersistor) : PaginationTask {
 
-    override fun execute(params: PaginationTask.Params): Try<TokenChunkEvent> {
+    override fun execute(params: PaginationTask.Params): Try<TokenChunkEventPersistor.Result> {
         val fakeEvents = RoomDataHelper.createFakeListOfEvents(30)
         val tokenChunkEvent = FakeTokenChunkEvent(params.from, Random.nextLong(System.currentTimeMillis()).toString(), fakeEvents)
         return tokenChunkEventPersistor.insertInDb(tokenChunkEvent, params.roomId, params.direction)
-                .map { tokenChunkEvent }
     }
 
 }

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/session/room/timeline/RoomDataHelper.kt

@@ -48,7 +48,7 @@ object RoomDataHelper {
             val chunkEntity = realm.createObject<ChunkEntity>().apply {
                 nextToken = null
                 prevToken = Random.nextLong(System.currentTimeMillis()).toString()
-                isLast = true
+                isLastForward = true
             }
             chunkEntity.addAll("roomId", eventList, PaginationDirection.FORWARDS)
             roomEntity.addOrUpdate(chunkEntity)

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/timeline/Timeline.kt

@@ -22,6 +22,8 @@ interface Timeline {
 
     var listener: Timeline.Listener?
 
+    fun hasMoreToLoad(direction: Direction): Boolean
+    fun hasReachedEnd(direction: Direction): Boolean
     fun size(): Int
     fun snapshot(): List<TimelineEvent>
     fun paginate(direction: Direction, count: Int)
@@ -44,14 +46,6 @@ interface Timeline {
          * These events come from a back pagination.
          */
         BACKWARDS("b");
-
-        fun reversed(): Direction {
-            return when (this) {
-                FORWARDS  -> BACKWARDS
-                BACKWARDS -> FORWARDS
-            }
-        }
-
     }
 
 

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/util/CancelableBag.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2019 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 im.vector.matrix.android.api.util
+
+class CancelableBag : Cancelable {
+
+    private val cancelableList = ArrayList<Cancelable>()
+
+    fun add(cancelable: Cancelable) {
+        cancelableList.add(cancelable)
+    }
+
+    override fun cancel() {
+        cancelableList.forEach { it.cancel() }
+    }
+
+}
+
+fun Cancelable.addTo(cancelables: CancelableBag) {
+    cancelables.add(this)
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/RealmLiveEntityObserver.kt

@@ -43,7 +43,6 @@ internal abstract class RealmLiveEntityObserver<T : RealmObject>(protected val m
                 queryResults.addChangeListener { t, changeSet ->
                     onChanged(t, changeSet)
                 }
-                processInitialResults(queryResults)
                 results = AtomicReference(queryResults)
             }
         }
@@ -61,7 +60,7 @@ internal abstract class RealmLiveEntityObserver<T : RealmObject>(protected val m
         return isStarted.get()
     }
 
-    protected open fun onChanged(realmResults: RealmResults<T>, changeSet: OrderedCollectionChangeSet) {
+    private fun onChanged(realmResults: RealmResults<T>, changeSet: OrderedCollectionChangeSet) {
         val insertionIndexes = changeSet.insertions
         val updateIndexes = changeSet.changes
         val deletionIndexes = changeSet.deletions
@@ -71,12 +70,6 @@ internal abstract class RealmLiveEntityObserver<T : RealmObject>(protected val m
         processChanges(inserted, updated, deleted)
     }
 
-    protected open fun processInitialResults(results: RealmResults<T>) {
+    protected abstract fun processChanges(inserted: List<T>, updated: List<T>, deleted: List<T>)
-        // no-op
-    }
-
-    protected open fun processChanges(inserted: List<T>, updated: List<T>, deleted: List<T>) {
-        //no-op
-    }
 
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/helper/ChunkEntityHelper.kt

@@ -27,18 +27,18 @@ import im.vector.matrix.android.internal.database.query.fastContains
 import im.vector.matrix.android.internal.session.room.timeline.PaginationDirection
 import io.realm.Sort
 
-internal fun ChunkEntity.deleteOnCascade() {
-    assertIsManaged()
-    this.events.deleteAllFromRealm()
-    this.deleteFromRealm()
-}
-
 // By default if a chunk is empty we consider it unlinked
 internal fun ChunkEntity.isUnlinked(): Boolean {
     assertIsManaged()
     return events.where().equalTo(EventEntityFields.IS_UNLINKED, false).findAll().isEmpty()
 }
 
+internal fun ChunkEntity.deleteOnCascade() {
+    assertIsManaged()
+    this.events.deleteAllFromRealm()
+    this.deleteFromRealm()
+}
+
 internal fun ChunkEntity.merge(roomId: String,
                                chunkToMerge: ChunkEntity,
                                direction: PaginationDirection) {
@@ -53,10 +53,11 @@ internal fun ChunkEntity.merge(roomId: String,
     val eventsToMerge: List<EventEntity>
     if (direction == PaginationDirection.FORWARDS) {
         this.nextToken = chunkToMerge.nextToken
-        this.isLast = chunkToMerge.isLast
+        this.isLastForward = chunkToMerge.isLastForward
         eventsToMerge = chunkToMerge.events.reversed()
     } else {
         this.prevToken = chunkToMerge.prevToken
+        this.isLastBackward = chunkToMerge.isLastBackward
         eventsToMerge = chunkToMerge.events
     }
     eventsToMerge.forEach {

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/model/ChunkEntity.kt

@@ -23,8 +23,9 @@ import io.realm.annotations.LinkingObjects
 
 internal open class ChunkEntity(var prevToken: String? = null,
                                 var nextToken: String? = null,
-                                var isLast: Boolean = false,
+                                var events: RealmList<EventEntity> = RealmList(),
-                                var events: RealmList<EventEntity> = RealmList()
+                                var isLastForward: Boolean = false,
+                                var isLastBackward: Boolean = false
 ) : RealmObject() {
 
     @LinkingObjects("chunks")

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/query/ChunkEntityQueries.kt

@@ -43,7 +43,7 @@ internal fun ChunkEntity.Companion.find(realm: Realm, roomId: String, prevToken:
 
 internal fun ChunkEntity.Companion.findLastLiveChunkFromRoom(realm: Realm, roomId: String): ChunkEntity? {
     return where(realm, roomId)
-            .equalTo(ChunkEntityFields.IS_LAST, true)
+            .equalTo(ChunkEntityFields.IS_LAST_FORWARD, true)
             .findFirst()
 }
 

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/DefaultGetContextOfEventTask.kt

@@ -17,12 +17,12 @@
 package im.vector.matrix.android.internal.session.room.timeline
 
 import arrow.core.Try
-import im.vector.matrix.android.internal.task.Task
 import im.vector.matrix.android.internal.network.executeRequest
 import im.vector.matrix.android.internal.session.room.RoomAPI
+import im.vector.matrix.android.internal.task.Task
 import im.vector.matrix.android.internal.util.FilterUtil
 
-internal interface GetContextOfEventTask : Task<GetContextOfEventTask.Params, TokenChunkEvent> {
+internal interface GetContextOfEventTask : Task<GetContextOfEventTask.Params, TokenChunkEventPersistor.Result> {
 
     data class Params(
             val roomId: String,
@@ -35,12 +35,12 @@ internal class DefaultGetContextOfEventTask(private val roomAPI: RoomAPI,
                                             private val tokenChunkEventPersistor: TokenChunkEventPersistor
 ) : GetContextOfEventTask {
 
-    override fun execute(params: GetContextOfEventTask.Params): Try<EventContextResponse> {
+    override fun execute(params: GetContextOfEventTask.Params): Try<TokenChunkEventPersistor.Result> {
         val filter = FilterUtil.createRoomEventFilter(true)?.toJSONString()
         return executeRequest<EventContextResponse> {
             apiCall = roomAPI.getContextOfEvent(params.roomId, params.eventId, 0, filter)
         }.flatMap { response ->
-            tokenChunkEventPersistor.insertInDb(response, params.roomId, PaginationDirection.BACKWARDS).map { response }
+            tokenChunkEventPersistor.insertInDb(response, params.roomId, PaginationDirection.BACKWARDS)
         }
     }
 

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/DefaultPaginationTask.kt

@@ -23,7 +23,7 @@ import im.vector.matrix.android.internal.task.Task
 import im.vector.matrix.android.internal.util.FilterUtil
 
 
-internal interface PaginationTask : Task<PaginationTask.Params, Boolean> {
+internal interface PaginationTask : Task<PaginationTask.Params, TokenChunkEventPersistor.Result> {
 
     data class Params(
             val roomId: String,
@@ -38,7 +38,7 @@ internal class DefaultPaginationTask(private val roomAPI: RoomAPI,
                                      private val tokenChunkEventPersistor: TokenChunkEventPersistor
 ) : PaginationTask {
 
-    override fun execute(params: PaginationTask.Params): Try<Boolean> {
+    override fun execute(params: PaginationTask.Params): Try<TokenChunkEventPersistor.Result> {
         val filter = FilterUtil.createRoomEventFilter(true)?.toJSONString()
         return executeRequest<PaginationResponse> {
             apiCall = roomAPI.getRoomMessagesFrom(params.roomId, params.from, params.direction.value, params.limit, filter)

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/DefaultTimeline.kt

@@ -18,10 +18,15 @@
 
 package im.vector.matrix.android.internal.session.room.timeline
 
-import androidx.annotation.UiThread
+import android.os.Handler
+import android.os.HandlerThread
 import im.vector.matrix.android.api.MatrixCallback
+import im.vector.matrix.android.api.session.events.model.EventType
 import im.vector.matrix.android.api.session.room.timeline.Timeline
 import im.vector.matrix.android.api.session.room.timeline.TimelineEvent
+import im.vector.matrix.android.api.util.CancelableBag
+import im.vector.matrix.android.api.util.addTo
+import im.vector.matrix.android.internal.database.model.ChunkEntity
 import im.vector.matrix.android.internal.database.model.ChunkEntityFields
 import im.vector.matrix.android.internal.database.model.EventEntity
 import im.vector.matrix.android.internal.database.model.EventEntityFields
@@ -29,18 +34,16 @@ import im.vector.matrix.android.internal.database.query.where
 import im.vector.matrix.android.internal.task.TaskExecutor
 import im.vector.matrix.android.internal.task.configureWith
 import im.vector.matrix.android.internal.util.PagingRequestHelper
-import io.realm.OrderedCollectionChangeSet
+import io.realm.*
-import io.realm.OrderedRealmCollectionChangeListener
-import io.realm.Realm
-import io.realm.RealmConfiguration
-import io.realm.RealmQuery
-import io.realm.RealmResults
-import io.realm.Sort
 import java.util.*
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicReference
 import kotlin.collections.ArrayList
 
 
-private const val INITIAL_LOAD_SIZE = 30
+private const val INITIAL_LOAD_SIZE = 20
+private const val THREAD_NAME = "TIMELINE_DB_THREAD"
 
 internal class DefaultTimeline(
         private val roomId: String,
@@ -54,16 +57,24 @@ internal class DefaultTimeline(
 ) : Timeline {
 
     override var listener: Timeline.Listener? = null
+        set(value) {
+            field = value
+            listener?.onUpdated(snapshot())
+        }
 
-    private lateinit var realm: Realm
+    private val isStarted = AtomicBoolean(false)
+    private val handlerThread = AtomicReference<HandlerThread>()
+    private val handler = AtomicReference<Handler>()
+    private val realm = AtomicReference<Realm>()
+
+    private val cancelableBag = CancelableBag()
     private lateinit var liveEvents: RealmResults<EventEntity>
     private var prevDisplayIndex: Int = 0
     private var nextDisplayIndex: Int = 0
     private val isLive = initialEventId == null
     private val builtEvents = Collections.synchronizedList<TimelineEvent>(ArrayList())
 
-
+    private val eventsChangeListener = OrderedRealmCollectionChangeListener<RealmResults<EventEntity>> { _, changeSet ->
-    private val changeListener = OrderedRealmCollectionChangeListener<RealmResults<EventEntity>> { _, changeSet ->
         if (changeSet.state == OrderedCollectionChangeSet.State.INITIAL) {
             handleInitialLoad()
         } else {
@@ -78,32 +89,48 @@ internal class DefaultTimeline(
         }
     }
 
-    @UiThread
     override fun paginate(direction: Timeline.Direction, count: Int) {
-        if (direction == Timeline.Direction.FORWARDS && isLive) {
+        handler.get()?.post {
-            return
+            if (!hasMoreToLoadLive(direction) && hasReachedEndLive(direction)) {
+                return@post
             }
             val startDisplayIndex = if (direction == Timeline.Direction.BACKWARDS) prevDisplayIndex else nextDisplayIndex
-        val hasBuiltCountItems = insertFromLiveResults(startDisplayIndex, direction, count.toLong())
+            val builtCountItems = insertFromLiveResults(startDisplayIndex, direction, count.toLong())
-        if (hasBuiltCountItems.not()) {
+            if (builtCountItems < count) {
-            val token = getToken(direction) ?: return
+                val limit = count - builtCountItems
-            helper.runIfNotRunning(direction.toRequestType()) {
+                val token = getTokenLive(direction) ?: return@post
-                executePaginationTask(it, token, direction.toPaginationDirection(), 30)
+                helper.runIfNotRunning(direction.toRequestType()) { executePaginationTask(it, token, direction, limit) }
             }
         }
     }
 
-    @UiThread
     override fun start() {
-        realm = Realm.getInstance(realmConfiguration)
+        if (isStarted.compareAndSet(false, true)) {
-        liveEvents = buildQuery(initialEventId).findAllAsync()
+            val handlerThread = HandlerThread(THREAD_NAME)
-        liveEvents.addChangeListener(changeListener)
+            handlerThread.start()
+            val handler = Handler(handlerThread.looper)
+            this.handlerThread.set(handlerThread)
+            this.handler.set(handler)
+            handler.post {
+                val realm = Realm.getInstance(realmConfiguration)
+                this.realm.set(realm)
+                liveEvents = buildEventQuery(realm).findAllAsync()
+                liveEvents.addChangeListener(eventsChangeListener)
+            }
+        }
+
     }
 
-    @UiThread
     override fun dispose() {
+        if (isStarted.compareAndSet(true, false)) {
+            handler.get()?.post {
+                cancelableBag.cancel()
                 liveEvents.removeAllChangeListeners()
-        realm.close()
+                realm.getAndSet(null)?.close()
+                handler.set(null)
+                handlerThread.getAndSet(null)?.quit()
+            }
+        }
     }
 
     override fun snapshot(): List<TimelineEvent> = synchronized(builtEvents) {
@@ -114,6 +141,21 @@ internal class DefaultTimeline(
         return builtEvents.size
     }
 
+    override fun hasReachedEnd(direction: Timeline.Direction): Boolean {
+        return handler.get()?.postAndWait {
+            hasReachedEndLive(direction)
+        } ?: false
+    }
+
+    override fun hasMoreToLoad(direction: Timeline.Direction): Boolean {
+        return handler.get()?.postAndWait {
+            hasMoreToLoadLive(direction)
+        } ?: false
+    }
+
+    /**
+     * This has to be called on TimelineThread as it access realm live results
+     */
     private fun handleInitialLoad() = synchronized(builtEvents) {
         val initialDisplayIndex = if (isLive) {
             liveEvents.firstOrNull()?.displayIndex
@@ -138,19 +180,22 @@ internal class DefaultTimeline(
 
     private fun executePaginationTask(requestCallback: PagingRequestHelper.Request.Callback,
                                       from: String,
-                                      direction: PaginationDirection,
+                                      direction: Timeline.Direction,
                                       limit: Int) {
 
         val params = PaginationTask.Params(roomId = roomId,
                 from = from,
-                                           direction = direction,
+                direction = direction.toPaginationDirection(),
                 limit = limit)
 
         paginationTask.configureWith(params)
                 .enableRetry()
-                .dispatchTo(object : MatrixCallback<Boolean> {
+                .dispatchTo(object : MatrixCallback<TokenChunkEventPersistor.Result> {
-                    override fun onSuccess(data: Boolean) {
+                    override fun onSuccess(data: TokenChunkEventPersistor.Result) {
                         requestCallback.recordSuccess()
+                        if (data == TokenChunkEventPersistor.Result.SHOULD_FETCH_MORE) {
+                            paginate(direction, limit)
+                        }
                     }
 
                     override fun onFailure(failure: Throwable) {
@@ -158,26 +203,63 @@ internal class DefaultTimeline(
                     }
                 })
                 .executeBy(taskExecutor)
+                .addTo(cancelableBag)
     }
 
-    private fun getToken(direction: Timeline.Direction): String? {
+    /**
-        val chunkEntity = liveEvents.firstOrNull()?.chunk?.firstOrNull() ?: return null
+     * This has to be called on TimelineThread as it access realm live results
+     */
+    private fun getTokenLive(direction: Timeline.Direction): String? {
+        val chunkEntity = getLiveChunk() ?: return null
         return if (direction == Timeline.Direction.BACKWARDS) chunkEntity.prevToken else chunkEntity.nextToken
     }
 
     /**
-     * This has to be called on MonarchyThread as it access realm live results
+     * This has to be called on TimelineThread as it access realm live results
-     * @return true if count items has been added
+     */
+    private fun hasReachedEndLive(direction: Timeline.Direction): Boolean {
+        val liveChunk = getLiveChunk() ?: return false
+        return if (direction == Timeline.Direction.FORWARDS) {
+            liveChunk.isLastForward
+        } else {
+            liveChunk.isLastBackward || liveEvents.lastOrNull()?.type == EventType.STATE_ROOM_CREATE
+        }
+    }
+
+    /**
+     * This has to be called on TimelineThread as it access realm live results
+     */
+    private fun hasMoreToLoadLive(direction: Timeline.Direction): Boolean {
+        if (liveEvents.isEmpty()) {
+            return true
+        }
+        return if (direction == Timeline.Direction.FORWARDS) {
+            builtEvents.firstOrNull()?.displayIndex != liveEvents.firstOrNull()?.displayIndex
+        } else {
+            builtEvents.lastOrNull()?.displayIndex != liveEvents.lastOrNull()?.displayIndex
+        }
+    }
+
+    /**
+     * This has to be called on TimelineThread as it access realm live results
+     */
+    private fun getLiveChunk(): ChunkEntity? {
+        return liveEvents.firstOrNull()?.chunk?.firstOrNull()
+    }
+
+    /**
+     * This has to be called on TimelineThread as it access realm live results
+     * @return number of items who have been added
      */
     private fun insertFromLiveResults(startDisplayIndex: Int,
                                       direction: Timeline.Direction,
-                                      count: Long): Boolean = synchronized(builtEvents) {
+                                      count: Long): Int = synchronized(builtEvents) {
         if (count < 1) {
             throw java.lang.IllegalStateException("You should provide a count superior to 0")
         }
         val offsetResults = getOffsetResults(startDisplayIndex, direction, count)
         if (offsetResults.isEmpty()) {
-            return false
+            return 0
         }
         val offsetIndex = offsetResults.last()!!.displayIndex
         if (direction == Timeline.Direction.BACKWARDS) {
@@ -191,9 +273,12 @@ internal class DefaultTimeline(
             builtEvents.add(position, timelineEvent)
         }
         listener?.onUpdated(snapshot())
-        return offsetResults.size.toLong() == count
+        return offsetResults.size
     }
 
+    /**
+     * This has to be called on TimelineThread as it access realm live results
+     */
     private fun getOffsetResults(startDisplayIndex: Int,
                                  direction: Timeline.Direction,
                                  count: Long): RealmResults<EventEntity> {
@@ -210,21 +295,33 @@ internal class DefaultTimeline(
         return offsetQuery.limit(count).findAll()
     }
 
-    private fun buildQuery(eventId: String?): RealmQuery<EventEntity> {
+    private fun buildEventQuery(realm: Realm): RealmQuery<EventEntity> {
-        val query = if (eventId == null) {
+        val query = if (initialEventId == null) {
             EventEntity
                     .where(realm, roomId = roomId, linkFilterMode = EventEntity.LinkFilterMode.LINKED_ONLY)
-                    .equalTo("${EventEntityFields.CHUNK}.${ChunkEntityFields.IS_LAST}", true)
+                    .equalTo("${EventEntityFields.CHUNK}.${ChunkEntityFields.IS_LAST_FORWARD}", true)
         } else {
             EventEntity
                     .where(realm, roomId = roomId, linkFilterMode = EventEntity.LinkFilterMode.BOTH)
-                    .`in`("${EventEntityFields.CHUNK}.${ChunkEntityFields.EVENTS.EVENT_ID}", arrayOf(eventId))
+                    .`in`("${EventEntityFields.CHUNK}.${ChunkEntityFields.EVENTS.EVENT_ID}", arrayOf(initialEventId))
         }
         query.sort(EventEntityFields.DISPLAY_INDEX, Sort.DESCENDING)
         return query
 
     }
 
+    private fun <T> Handler.postAndWait(runnable: () -> T): T {
+        val lock = CountDownLatch(1)
+        val atomicReference = AtomicReference<T>()
+        post {
+            val result = runnable()
+            atomicReference.set(result)
+            lock.countDown()
+        }
+        lock.await()
+        return atomicReference.get()
+    }
+
     private fun Timeline.Direction.toRequestType(): PagingRequestHelper.RequestType {
         return if (this == Timeline.Direction.BACKWARDS) PagingRequestHelper.RequestType.BEFORE else PagingRequestHelper.RequestType.AFTER
     }
@@ -233,4 +330,5 @@ internal class DefaultTimeline(
     private fun Timeline.Direction.toPaginationDirection(): PaginationDirection {
         return if (this == Timeline.Direction.BACKWARDS) PaginationDirection.BACKWARDS else PaginationDirection.FORWARDS
     }
+
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/DefaultTimelineService.kt

@@ -16,12 +16,9 @@
 
 package im.vector.matrix.android.internal.session.room.timeline
 
-import androidx.paging.PagedList
 import com.zhuinden.monarchy.Monarchy
 import im.vector.matrix.android.api.session.room.timeline.Timeline
-import im.vector.matrix.android.api.session.room.timeline.TimelineEventInterceptor
 import im.vector.matrix.android.api.session.room.timeline.TimelineService
-import im.vector.matrix.android.internal.database.model.ChunkEntityFields
 import im.vector.matrix.android.internal.database.model.EventEntity
 import im.vector.matrix.android.internal.database.model.EventEntityFields
 import im.vector.matrix.android.internal.database.query.where
@@ -29,12 +26,7 @@ import im.vector.matrix.android.internal.task.TaskExecutor
 import im.vector.matrix.android.internal.task.configureWith
 import im.vector.matrix.android.internal.util.PagingRequestHelper
 import im.vector.matrix.android.internal.util.tryTransactionAsync
-import io.realm.Realm
-import io.realm.RealmQuery
-import io.realm.Sort
 
-private const val PAGE_SIZE = 100
-private const val PREFETCH_DISTANCE = 30
 private const val EVENT_NOT_FOUND_INDEX = -1
 
 internal class DefaultTimelineService(private val roomId: String,
@@ -46,8 +38,6 @@ internal class DefaultTimelineService(private val roomId: String,
                                       private val helper: PagingRequestHelper
 ) : TimelineService {
 
-    private val eventInterceptors = ArrayList<TimelineEventInterceptor>()
-
     override fun createTimeline(eventId: String?): Timeline {
         return DefaultTimeline(roomId, eventId, monarchy.realmConfiguration, taskExecutor, contextOfEventTask, timelineEventFactory, paginationTask, helper)
     }
@@ -73,15 +63,6 @@ internal class DefaultTimelineService(private val roomId: String,
         contextOfEventTask.configureWith(params).executeBy(taskExecutor)
     }
 
-    private fun buildPagedListConfig(): PagedList.Config {
-        return PagedList.Config.Builder()
-                .setEnablePlaceholders(false)
-                .setPageSize(PAGE_SIZE)
-                .setInitialLoadSizeHint(2 * PAGE_SIZE)
-                .setPrefetchDistance(PREFETCH_DISTANCE)
-                .build()
-    }
-
     private fun clearUnlinkedEvents() {
         monarchy.tryTransactionAsync { realm ->
             val unlinkedEvents = EventEntity
@@ -101,18 +82,5 @@ internal class DefaultTimelineService(private val roomId: String,
         return displayIndex
     }
 
-    private fun buildDataSourceFactoryQuery(realm: Realm, eventId: String?): RealmQuery<EventEntity> {
-        val query = if (eventId == null) {
-            EventEntity
-                    .where(realm, roomId = roomId, linkFilterMode = EventEntity.LinkFilterMode.LINKED_ONLY)
-                    .equalTo("${EventEntityFields.CHUNK}.${ChunkEntityFields.IS_LAST}", true)
-        } else {
-            EventEntity
-                    .where(realm, roomId = roomId, linkFilterMode = EventEntity.LinkFilterMode.BOTH)
-                    .`in`("${EventEntityFields.CHUNK}.${ChunkEntityFields.EVENTS.EVENT_ID}", arrayOf(eventId))
-        }
-        return query.sort(EventEntityFields.DISPLAY_INDEX, Sort.DESCENDING)
-    }
-
 
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/TimelineBoundaryCallback.kt

@@ -95,8 +95,8 @@ internal class TimelineBoundaryCallback(private val roomId: String,
 
         paginationTask.configureWith(params)
                 .enableRetry()
-                .dispatchTo(object : MatrixCallback<Boolean> {
+                .dispatchTo(object : MatrixCallback<TokenChunkEventPersistor.Result> {
-                    override fun onSuccess(data: Boolean) {
+                    override fun onSuccess(data: TokenChunkEventPersistor.Result) {
                         requestCallback.recordSuccess()
                     }
 

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/TokenChunkEventPersistor.kt

@@ -36,13 +36,15 @@ import io.realm.kotlin.createObject
 
 internal class TokenChunkEventPersistor(private val monarchy: Monarchy) {
 
+    enum class Result {
+        SHOULD_FETCH_MORE,
+        SUCCESS
+    }
+
     fun insertInDb(receivedChunk: TokenChunkEvent,
                    roomId: String,
-                   direction: PaginationDirection): Try<Boolean> {
+                   direction: PaginationDirection): Try<Result> {
 
-        if (receivedChunk.events.isEmpty() && receivedChunk.stateEvents.isEmpty()) {
-            return Try.just(false)
-        }
         return monarchy
                 .tryTransactionSync { realm ->
                     val roomEntity = RoomEntity.where(realm, roomId).findFirst()
@@ -71,7 +73,9 @@ internal class TokenChunkEventPersistor(private val monarchy: Monarchy) {
                         nextChunk?.apply { this.prevToken = prevToken }
                         ?: ChunkEntity.create(realm, prevToken, nextToken)
                     }
-
+                    if (receivedChunk.events.isEmpty() && receivedChunk.end == receivedChunk.start) {
+                        currentChunk.isLastBackward = true
+                    } else {
                         currentChunk.addAll(roomId, receivedChunk.events, direction, isUnlinked = currentChunk.isUnlinked())
 
                         // Then we merge chunks if needed
@@ -91,7 +95,14 @@ internal class TokenChunkEventPersistor(private val monarchy: Monarchy) {
                         roomEntity.addOrUpdate(currentChunk)
                         roomEntity.addStateEvents(receivedChunk.stateEvents, isUnlinked = currentChunk.isUnlinked())
                     }
-                .map { true }
+                }
+                .map {
+                    if (receivedChunk.events.isEmpty() && receivedChunk.stateEvents.isEmpty() && receivedChunk.start != receivedChunk.end) {
+                        Result.SHOULD_FETCH_MORE
+                    } else {
+                        Result.SUCCESS
+                    }
+                }
     }
 
     private fun handleMerge(roomEntity: RoomEntity,

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/sync/RoomSyncHandler.kt

@@ -51,7 +51,6 @@ internal class RoomSyncHandler(private val monarchy: Monarchy,
         data class INVITED(val data: Map<String, InvitedRoomSync>) : HandlingStrategy()
         data class LEFT(val data: Map<String, RoomSync>) : HandlingStrategy()
     }
-
     fun handle(roomsSyncResponse: RoomsSyncResponse) {
         monarchy.runTransactionSync { realm ->
             handleRoomSync(realm, RoomSyncHandler.HandlingStrategy.JOINED(roomsSyncResponse.join))
@@ -164,8 +163,8 @@ internal class RoomSyncHandler(private val monarchy: Monarchy,
             realm.createObject<ChunkEntity>().apply { this.prevToken = prevToken }
         }
 
-        lastChunk?.isLast = false
+        lastChunk?.isLastForward = false
-        chunkEntity.isLast = true
+        chunkEntity.isLastForward = true
         chunkEntity.addAll(roomId, eventList, PaginationDirection.FORWARDS, stateIndexOffset)
         return chunkEntity
     }