From 9a592e9c7e905c9ce64ebaccea41f347088aedb4 Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoitm@matrix.org>
Date: Wed, 3 Jun 2020 01:13:02 +0200
Subject: [PATCH] Create IsUselessResolver object

---
 .../android/api/session/events/model/Event.kt |  2 +
 .../internal/database/mapper/EventMapper.kt   |  6 +--
 .../database/mapper/IsUselessResolver.kt      | 37 +++++++++++++++++++
 3 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/IsUselessResolver.kt

diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/events/model/Event.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/events/model/Event.kt
index d3780ebe60..ddf016b015 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/events/model/Event.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/events/model/Event.kt
@@ -162,6 +162,8 @@ data class Event(
      */
     fun isRedactedBySameUser() = senderId == unsignedData?.redactedEvent?.senderId
 
+    fun resolvedPrevContent(): Content? = prevContent ?: unsignedData?.prevContent
+
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
         if (javaClass != other?.javaClass) return false
diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/EventMapper.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/EventMapper.kt
index 6c90a67161..e28de760fd 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/EventMapper.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/EventMapper.kt
@@ -19,7 +19,6 @@ package im.vector.matrix.android.internal.database.mapper
 import com.squareup.moshi.JsonDataException
 import im.vector.matrix.android.api.session.crypto.MXCryptoError
 import im.vector.matrix.android.api.session.events.model.Event
-import im.vector.matrix.android.api.session.events.model.EventType
 import im.vector.matrix.android.api.session.events.model.UnsignedData
 import im.vector.matrix.android.api.session.room.send.SendState
 import im.vector.matrix.android.internal.crypto.algorithms.olm.OlmDecryptionResult
@@ -37,9 +36,8 @@ internal object EventMapper {
         eventEntity.eventId = event.eventId ?: "$$roomId-${System.currentTimeMillis()}-${event.hashCode()}"
         eventEntity.roomId = event.roomId ?: roomId
         eventEntity.content = ContentMapper.map(event.content)
-        val resolvedPrevContent = event.prevContent ?: event.unsignedData?.prevContent
-        eventEntity.prevContent = ContentMapper.map(resolvedPrevContent)
-        eventEntity.isUseless = event.type == EventType.STATE_ROOM_MEMBER && eventEntity.content == eventEntity.prevContent
+        eventEntity.prevContent = ContentMapper.map(event.resolvedPrevContent())
+        eventEntity.isUseless = IsUselessResolver.isUseless(event)
         eventEntity.stateKey = event.stateKey
         eventEntity.type = event.type
         eventEntity.sender = event.senderId
diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/IsUselessResolver.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/IsUselessResolver.kt
new file mode 100644
index 0000000000..eb149467b0
--- /dev/null
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/database/mapper/IsUselessResolver.kt
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2020 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.database.mapper
+
+import im.vector.matrix.android.api.session.events.model.Event
+import im.vector.matrix.android.api.session.events.model.EventType
+import im.vector.matrix.android.api.session.events.model.toContent
+
+internal object IsUselessResolver {
+
+    /**
+     * @return true if the event is useless
+     */
+    fun isUseless(event: Event): Boolean {
+        return when (event.type) {
+            EventType.STATE_ROOM_MEMBER -> {
+                // Call toContent(), to filter out null value
+                event.content?.toContent() == event.resolvedPrevContent()?.toContent()
+            }
+            else                        -> false
+        }
+    }
+}