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

96 lines
3.9 KiB
Kotlin

/*
* 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.internal.session.room.timeline
import im.vector.matrix.android.internal.database.model.ReadMarkerEntity
import im.vector.matrix.android.internal.database.model.TimelineEventEntity
import im.vector.matrix.android.internal.database.model.TimelineEventEntityFields
import im.vector.matrix.android.internal.database.query.where
import io.realm.Realm
import io.realm.RealmObjectChangeListener
import io.realm.RealmResults
/**
* This class is responsible for handling the read marker for hidden events.
* When an hidden event has read marker, we want to transfer it on the first older displayed event.
* It has to be used in [DefaultTimeline] and we should call the [start] and [dispose] methods to properly handle realm subscription.
*/
internal class TimelineHiddenReadMarker constructor(private val roomId: String) {
interface Delegate {
fun rebuildEvent(eventId: String, hasReadMarker: Boolean): Boolean
fun onReadMarkerUpdated()
}
private var previousDisplayedEventId: String? = null
private var readMarkerEntity: ReadMarkerEntity? = null
private lateinit var liveEvents: RealmResults<TimelineEventEntity>
private lateinit var delegate: Delegate
private val readMarkerListener = RealmObjectChangeListener<ReadMarkerEntity> { readMarker, _ ->
var hasChange = false
previousDisplayedEventId?.also {
hasChange = delegate.rebuildEvent(it, false)
previousDisplayedEventId = null
}
val isEventHidden = liveEvents.where().equalTo(TimelineEventEntityFields.EVENT_ID, readMarker.eventId).findFirst() == null
if (isEventHidden) {
val hiddenEvent = readMarker.timelineEvent?.firstOrNull()
?: return@RealmObjectChangeListener
val displayIndex = hiddenEvent.root?.displayIndex
if (displayIndex != null) {
// Then we are looking for the first displayable event after the hidden one
val firstDisplayedEvent = liveEvents.where()
.lessThanOrEqualTo(TimelineEventEntityFields.ROOT.DISPLAY_INDEX, displayIndex)
.findFirst()
// If we find one, we should rebuild this one with marker
if (firstDisplayedEvent != null) {
previousDisplayedEventId = firstDisplayedEvent.eventId
hasChange = delegate.rebuildEvent(firstDisplayedEvent.eventId, true)
}
}
}
if (hasChange) delegate.onReadMarkerUpdated()
}
/**
* Start the realm query subscription. Has to be called on an HandlerThread
*/
fun start(realm: Realm, liveEvents: RealmResults<TimelineEventEntity>, delegate: Delegate) {
this.liveEvents = liveEvents
this.delegate = delegate
// We are looking for read receipts set on hidden events.
// We only accept those with a timelineEvent (so coming from pagination/sync).
readMarkerEntity = ReadMarkerEntity.where(realm, roomId = roomId)
.findFirstAsync()
.also { it.addChangeListener(readMarkerListener) }
}
/**
* Dispose the realm query subscription. Has to be called on an HandlerThread
*/
fun dispose() {
this.readMarkerEntity?.removeAllChangeListeners()
}
}