From 243ce23055ee06982238dda5fe0b6c8f8cc2cb92 Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoit@matrix.org>
Date: Wed, 29 Jan 2025 10:35:52 +0100
Subject: [PATCH] Protect access to member timeline with a Mutex and clean the
 code.

---
 .../impl/datasource/MediaTimeline.kt          | 22 +++++++++----------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/datasource/MediaTimeline.kt b/libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/datasource/MediaTimeline.kt
index 5b26b50d62..6dc4136193 100644
--- a/libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/datasource/MediaTimeline.kt
+++ b/libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/datasource/MediaTimeline.kt
@@ -18,6 +18,8 @@ import io.element.android.libraries.mediaviewer.impl.model.GroupedMediaItems
 import io.element.android.libraries.mediaviewer.impl.model.MediaItem
 import io.element.android.libraries.mediaviewer.impl.model.hasEvent
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import javax.inject.Inject
 
 interface MediaTimeline {
@@ -37,19 +39,15 @@ class LiveMediaTimeline @Inject constructor(
     private val room: MatrixRoom,
 ) : MediaTimeline {
     private var timeline: Timeline? = null
-    override suspend fun getTimeline(): Result<Timeline> {
-        return if (timeline == null) {
-            room.mediaTimeline(null).fold(
-                {
-                    timeline = it
-                    Result.success(it)
-                },
-                {
-                    Result.failure(it)
-                },
-            )
+    private val mutex = Mutex()
+
+    override suspend fun getTimeline(): Result<Timeline> = mutex.withLock {
+        val currentTimeline = timeline
+        if (currentTimeline == null) {
+            room.mediaTimeline(null)
+                .onSuccess { timeline = it }
         } else {
-            Result.success(timeline!!)
+            Result.success(currentTimeline)
         }
     }