Hide verbose state events from the timeline (#2225)

changelog.d/2216.bugfix

@@ -0,0 +1 @@
+Hide verbose state events from the timeline

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/timeline/item/event/EventContent.kt

@@ -85,7 +85,11 @@ data class ProfileChangeContent(
 data class StateContent(
     val stateKey: String,
     val content: OtherState
-) : EventContent
+) : EventContent {
+    fun isVisibleInTimeline(): Boolean {
+        return content.isVisibleInTimeline()
+    }
+}
 
 data class FailedToParseMessageLikeContent(
     val eventType: String,

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/timeline/item/event/OtherState.kt

@@ -41,4 +41,30 @@ sealed interface OtherState {
     data object SpaceChild : OtherState
     data object SpaceParent : OtherState
     data class Custom(val eventType: String) : OtherState
+
+    fun isVisibleInTimeline() = when (this) {
+        // Visible
+        is RoomAvatar,
+        is RoomName,
+        is RoomTopic,
+        is RoomThirdPartyInvite,
+        is RoomCreate,
+        is RoomEncryption,
+        is Custom -> true
+        // Hidden
+        is RoomAliases,
+        is RoomCanonicalAlias,
+        is RoomGuestAccess,
+        is RoomHistoryVisibility,
+        is RoomJoinRules,
+        is RoomPinnedEvents,
+        is RoomPowerLevels,
+        is RoomServerAcl,
+        is RoomTombstone,
+        is SpaceChild,
+        is SpaceParent,
+        is PolicyRuleRoom,
+        is PolicyRuleServer,
+        is PolicyRuleUser -> false
+    }
 }

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

@@ -27,6 +27,7 @@ import io.element.android.libraries.matrix.impl.timeline.item.event.EventMessage
 import io.element.android.libraries.matrix.impl.timeline.item.event.EventTimelineItemMapper
 import io.element.android.libraries.matrix.impl.timeline.item.event.TimelineEventContentMapper
 import io.element.android.libraries.matrix.impl.timeline.item.virtual.VirtualTimelineItemMapper
+import io.element.android.libraries.matrix.impl.timeline.postprocessor.FilterHiddenStateEventsProcessor
 import io.element.android.libraries.matrix.impl.timeline.postprocessor.TimelineEncryptedHistoryPostProcessor
 import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.CoroutineDispatcher
@@ -82,6 +83,8 @@ class RustMatrixTimeline(
         dispatcher = dispatcher,
     )
 
+    private val filterHiddenStateEventsProcessor = FilterHiddenStateEventsProcessor()
+
     private val timelineItemFactory = MatrixTimelineItemMapper(
         fetchDetailsForEvent = this::fetchDetailsForEvent,
         roomCoroutineScope = roomCoroutineScope,
@@ -101,9 +104,9 @@ class RustMatrixTimeline(
     override val paginationState: StateFlow<MatrixTimeline.PaginationState> = _paginationState.asStateFlow()
 
     @OptIn(ExperimentalCoroutinesApi::class)
-    override val timelineItems: Flow<List<MatrixTimelineItem>> = _timelineItems.mapLatest { items ->
+    override val timelineItems: Flow<List<MatrixTimelineItem>> = _timelineItems
-        encryptedHistoryPostProcessor.process(items)
+        .mapLatest { items -> encryptedHistoryPostProcessor.process(items) }
-    }
+        .mapLatest { items -> filterHiddenStateEventsProcessor.process(items) }
 
     init {
         Timber.d("Initialize timeline for room ${matrixRoom.roomId}")

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/timeline/postprocessor/FilterHiddenStateEventsProcessor.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2024 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.impl.timeline.postprocessor
+
+import io.element.android.libraries.matrix.api.timeline.MatrixTimelineItem
+import io.element.android.libraries.matrix.api.timeline.item.event.StateContent
+
+/**
+ * This class is used to filter out 'hidden' state events from the timeline.
+ */
+class FilterHiddenStateEventsProcessor {
+    fun process(items: List<MatrixTimelineItem>): List<MatrixTimelineItem> {
+        return items.filter { item ->
+            when (item) {
+                is MatrixTimelineItem.Event -> {
+                    when (val content = item.event.content) {
+                        // If it's a state event, make sure it's visible
+                        is StateContent -> content.isVisibleInTimeline()
+                        // We can display any other event
+                        else -> true
+                    }
+                }
+                is MatrixTimelineItem.Virtual -> true
+                is MatrixTimelineItem.Other -> true
+            }
+        }
+    }
+}

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/timeline/postprocessor/FilterHiddenStateEventsProcessorTest.kt

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2024 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.impl.timeline.postprocessor
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.matrix.api.timeline.MatrixTimelineItem
+import io.element.android.libraries.matrix.api.timeline.item.event.OtherState
+import io.element.android.libraries.matrix.api.timeline.item.event.StateContent
+import io.element.android.libraries.matrix.api.timeline.item.virtual.VirtualTimelineItem
+import io.element.android.libraries.matrix.test.timeline.anEventTimelineItem
+import org.junit.Test
+
+class FilterHiddenStateEventsProcessorTest {
+    @Test
+    fun test() {
+        val items = listOf(
+            // These are visible because they're not state events
+            MatrixTimelineItem.Other,
+            MatrixTimelineItem.Virtual("virtual", VirtualTimelineItem.ReadMarker),
+            MatrixTimelineItem.Event("event", anEventTimelineItem()),
+            // These are visible state events
+            MatrixTimelineItem.Event("m.room.avatar", anEventTimelineItem(content = StateContent("", OtherState.RoomAvatar("")))),
+            MatrixTimelineItem.Event("m.room.create", anEventTimelineItem(content = StateContent("", OtherState.RoomCreate))),
+            MatrixTimelineItem.Event("m.room.encrypted", anEventTimelineItem(content = StateContent("", OtherState.RoomEncryption))),
+            MatrixTimelineItem.Event("m.room.name", anEventTimelineItem(content = StateContent("", OtherState.RoomName("")))),
+            MatrixTimelineItem.Event("m.room.third_party_invite", anEventTimelineItem(content = StateContent("", OtherState.RoomThirdPartyInvite("")))),
+            MatrixTimelineItem.Event("m.room.topic", anEventTimelineItem(content = StateContent("", OtherState.RoomTopic("")))),
+            MatrixTimelineItem.Event("m.room.custom", anEventTimelineItem(content = StateContent("", OtherState.Custom("")))),
+            // These ones are hidden
+            MatrixTimelineItem.Event("m.room.aliases", anEventTimelineItem(content = StateContent("", OtherState.RoomAliases))),
+            MatrixTimelineItem.Event("m.room.canonical_alias", anEventTimelineItem(content = StateContent("", OtherState.RoomCanonicalAlias))),
+            MatrixTimelineItem.Event("m.room.guest_access", anEventTimelineItem(content = StateContent("", OtherState.RoomGuestAccess))),
+            MatrixTimelineItem.Event("m.room.history_visibility", anEventTimelineItem(content = StateContent("", OtherState.RoomHistoryVisibility))),
+            MatrixTimelineItem.Event("m.room.join_rules", anEventTimelineItem(content = StateContent("", OtherState.RoomJoinRules))),
+            MatrixTimelineItem.Event("m.room.pinned_events", anEventTimelineItem(content = StateContent("", OtherState.RoomPinnedEvents))),
+            MatrixTimelineItem.Event("m.room.power_levels", anEventTimelineItem(content = StateContent("", OtherState.RoomPowerLevels))),
+            MatrixTimelineItem.Event("m.room.server_acl", anEventTimelineItem(content = StateContent("", OtherState.RoomServerAcl))),
+            MatrixTimelineItem.Event("m.room.tombstone", anEventTimelineItem(content = StateContent("", OtherState.RoomTombstone))),
+            MatrixTimelineItem.Event("m.space.child", anEventTimelineItem(content = StateContent("", OtherState.SpaceChild))),
+            MatrixTimelineItem.Event("m.space.parent", anEventTimelineItem(content = StateContent("", OtherState.SpaceParent))),
+            MatrixTimelineItem.Event("m.room.policy.rule.room", anEventTimelineItem(content = StateContent("", OtherState.PolicyRuleRoom))),
+            MatrixTimelineItem.Event("m.room.policy.rule.server", anEventTimelineItem(content = StateContent("", OtherState.PolicyRuleServer))),
+            MatrixTimelineItem.Event("m.room.policy.rule.user", anEventTimelineItem(content = StateContent("", OtherState.PolicyRuleUser))),
+        )
+
+        val expected = listOf(
+            MatrixTimelineItem.Other,
+            MatrixTimelineItem.Virtual("virtual", VirtualTimelineItem.ReadMarker),
+            MatrixTimelineItem.Event("event", anEventTimelineItem()),
+            MatrixTimelineItem.Event("m.room.avatar", anEventTimelineItem(content = StateContent("", OtherState.RoomAvatar("")))),
+            MatrixTimelineItem.Event("m.room.create", anEventTimelineItem(content = StateContent("", OtherState.RoomCreate))),
+            MatrixTimelineItem.Event("m.room.encrypted", anEventTimelineItem(content = StateContent("", OtherState.RoomEncryption))),
+            MatrixTimelineItem.Event("m.room.name", anEventTimelineItem(content = StateContent("", OtherState.RoomName("")))),
+            MatrixTimelineItem.Event("m.room.third_party_invite", anEventTimelineItem(content = StateContent("", OtherState.RoomThirdPartyInvite("")))),
+            MatrixTimelineItem.Event("m.room.topic", anEventTimelineItem(content = StateContent("", OtherState.RoomTopic("")))),
+            MatrixTimelineItem.Event("m.room.custom", anEventTimelineItem(content = StateContent("", OtherState.Custom("")))),
+        )
+
+        val processor = FilterHiddenStateEventsProcessor()
+
+        assertThat(processor.process(items)).isEqualTo(expected)
+    }
+}