Don't leak MediaFileHandle when downloading voice messages (#1748)

Uses the new `MediaFile.persist()` [API](https://github.com/matrix-org/matrix-rust-sdk/pull/2789) to cache voice messages.
This allows to close the `MediaFile` handle after use and keeping the file.
Also disables rust sdk caching for voice messages as we'll use the app's cache dir for that purpose.

Fixes: https://github.com/vector-im/element-meta/issues/2175

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/voicemessages/timeline/VoiceMessageMediaRepo.kt

@@ -24,7 +24,6 @@ import io.element.android.libraries.di.CacheDirectory
 import io.element.android.libraries.di.RoomScope
 import io.element.android.libraries.matrix.api.media.MatrixMediaLoader
 import io.element.android.libraries.matrix.api.media.MediaSource
-import io.element.android.libraries.matrix.api.media.toFile
 import java.io.File
 
 /**
@@ -90,14 +89,15 @@ class DefaultVoiceMessageMediaRepo @AssistedInject constructor(
             source = mediaSource,
             mimeType = mimeType,
             body = body,
+            useCache = false,
         ).mapCatching {
-            val dest = cachedFile.apply { parentFile?.mkdirs() }
-            // TODO By not closing the MediaFile we're leaking the rust file handle here.
-            // Not that big of a deal but better to avoid it someday.
-            if (it.toFile().renameTo(dest)) {
-                dest
-            } else {
-                error("Failed to move file to cache.")
+            it.use { mediaFile ->
+                val dest = cachedFile.apply { parentFile?.mkdirs() }
+                if (mediaFile.persist(dest.path)) {
+                    dest
+                } else {
+                    error("Failed to move file to cache.")
+                }
             }
         }
     }

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/media/MatrixMediaLoader.kt

@@ -35,7 +35,13 @@ interface MatrixMediaLoader {
      * @param source to fetch the data for.
      * @param mimeType: optional mime type.
      * @param body: optional body which will be used to name the file.
+     * @param useCache: if true, the rust sdk will cache the media in its store.
      * @return a [Result] of [MediaFile]
      */
-    suspend fun downloadMediaFile(source: MediaSource, mimeType: String?, body: String?): Result<MediaFile>
+    suspend fun downloadMediaFile(
+        source: MediaSource,
+        mimeType: String?,
+        body: String?,
+        useCache: Boolean = true,
+    ): Result<MediaFile>
 }

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/media/MediaFile.kt

@@ -21,10 +21,16 @@ import java.io.File
 
 /**
  * A wrapper around a media file on the disk.
- * When closed the file will be removed from the disk.
+ * When closed the file will be removed from the disk unless [persist] has been used.
  */
 interface MediaFile : Closeable {
     fun path(): String
+
+    /**
+     * Persists the temp file to the given path. The file will be moved to
+     * the given path and won't be deleted anymore when closing the handle.
+     */
+    fun persist(path: String): Boolean
 }
 
 fun MediaFile.toFile(): File {

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/media/RustMediaFile.kt

@@ -25,6 +25,10 @@ class RustMediaFile(private val inner: MediaFileHandle) : MediaFile {
         return inner.path()
     }
 
+    override fun persist(path: String): Boolean {
+        return inner.persist(path)
+    }
+
     override fun close() {
         inner.close()
     }

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/media/RustMediaLoader.kt

@@ -71,7 +71,12 @@ class RustMediaLoader(
             }
         }
 
-    override suspend fun downloadMediaFile(source: MediaSource, mimeType: String?, body: String?): Result<MediaFile> =
+    override suspend fun downloadMediaFile(
+        source: MediaSource,
+        mimeType: String?,
+        body: String?,
+        useCache: Boolean,
+    ): Result<MediaFile> =
         withContext(mediaDispatcher) {
             runCatching {
                 source.toRustMediaSource().use { mediaSource ->
@@ -79,7 +84,7 @@ class RustMediaLoader(
                         mediaSource = mediaSource,
                         body = body,
                         mimeType = mimeType ?: MimeTypes.OctetStream,
-                        useCache = true,
+                        useCache = useCache,
                         tempDir = cacheDirectory.path,
                     )
                     RustMediaFile(mediaFile)

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/media/FakeMediaFile.kt

@@ -17,11 +17,16 @@
 package io.element.android.libraries.matrix.test.media
 
 import io.element.android.libraries.matrix.api.media.MediaFile
+import java.io.File
 
 class FakeMediaFile(private val path: String) : MediaFile {
     override fun path(): String {
         return path
     }
 
+    override fun persist(path: String): Boolean {
+        return File(path()).renameTo(File(path))
+    }
+
     override fun close() = Unit
 }

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/media/FakeMediaLoader.kt

@@ -42,7 +42,12 @@ class FakeMediaLoader : MatrixMediaLoader {
         }
     }
 
-    override suspend fun downloadMediaFile(source: MediaSource, mimeType: String?, body: String?): Result<MediaFile> = simulateLongTask {
+    override suspend fun downloadMediaFile(
+        source: MediaSource,
+        mimeType: String?,
+        body: String?,
+        useCache: Boolean,
+    ): Result<MediaFile> = simulateLongTask {
         if (shouldFail) {
             Result.failure(RuntimeException())
         } else {