Merge pull request #126 from stoyicker:cap_concurrent_remove_tasks

PiperOrigin-RevId: 463792127
(cherry picked from commit 7f08ab72)

RELEASENOTES.md

@@ -9,6 +9,9 @@
     *   Use `SingleThreadExecutor` for releasing `AudioTrack` instances to avoid
         OutOfMemory errors when releasing multiple players at the same time
         ([#10057](https://github.com/google/ExoPlayer/issues/10057)).
+    *   Limit parallel download removals to 1 to avoid excessive thread creation
+        ([#10458](https://github.com/google/ExoPlayer/issues/10458)).
+*   Metadata:
     *   `MetadataRenderer` can now be configured to render metadata as soon as
         they are available. Create an instance with
         `MetadataRenderer(MetadataOutput, Looper, MetadataDecoderFactory,

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/offline/DownloadManager.java

@@ -709,6 +709,7 @@ public final class DownloadManager {
     private int maxParallelDownloads;
     private int minRetryCount;
     private int activeDownloadTaskCount;
+    private boolean hasActiveRemoveTask;
 
     public InternalHandler(
         HandlerThread thread,
@@ -1060,6 +1061,10 @@ public final class DownloadManager {
         return;
       }
 
+      if (hasActiveRemoveTask) {
+        return;
+      }
+
       // We can start a remove task.
       Downloader downloader = downloaderFactory.createDownloader(download.request);
       activeTask =
@@ -1071,6 +1076,7 @@ public final class DownloadManager {
               minRetryCount,
               /* internalHandler= */ this);
       activeTasks.put(download.request.id, activeTask);
+      hasActiveRemoveTask = true;
       activeTask.start();
     }
 
@@ -1100,7 +1106,9 @@ public final class DownloadManager {
       activeTasks.remove(downloadId);
 
       boolean isRemove = task.isRemove;
-      if (!isRemove && --activeDownloadTaskCount == 0) {
+      if (isRemove) {
+        hasActiveRemoveTask = false;
+      } else if (--activeDownloadTaskCount == 0) {
         removeMessages(MSG_UPDATE_PROGRESS);
       }
 

libraries/exoplayer/src/test/java/androidx/media3/exoplayer/offline/DownloadManagerTest.java

@@ -284,14 +284,14 @@ public class DownloadManagerTest {
     postRemoveAllRequest();
     // Both downloads should be removed.
     FakeDownloader downloader2 = getDownloaderAt(2);
-    FakeDownloader downloader3 = getDownloaderAt(3);
     downloader2.assertId(ID1);
-    downloader3.assertId(ID2);
     downloader2.assertRemoveStarted();
-    downloader3.assertRemoveStarted();
     downloader2.finish();
-    downloader3.finish();
     assertRemoved(ID1);
+    FakeDownloader downloader3 = getDownloaderAt(3);
+    downloader3.assertId(ID2);
+    downloader3.assertRemoveStarted();
+    downloader3.finish();
     assertRemoved(ID2);
 
     downloadManagerListener.blockUntilIdleAndThrowAnyFailure();
@@ -713,6 +713,36 @@ public class DownloadManagerTest {
     assertEqualIgnoringUpdateTime(mergedDownload, expectedDownload);
   }
 
+  @Test
+  public void removeRequests_runSequentially() throws Throwable {
+    // Trigger two remove requests.
+    postDownloadRequest(ID1);
+    getDownloaderAt(0).finish();
+    postDownloadRequest(ID2);
+    getDownloaderAt(1).finish();
+    postRemoveRequest(ID1);
+    postRemoveRequest(ID2);
+
+    // Assert first remove request is executing, second one is queued.
+    assertRemoving(ID1);
+    assertQueued(ID2);
+    FakeDownloader downloader2 = getDownloaderAt(2);
+    downloader2.assertId(ID1);
+    downloader2.assertRemoveStarted();
+    downloader2.finish();
+    assertRemoved(ID1);
+
+    // Assert second one is running after first one finished
+    assertRemoving(ID2);
+    FakeDownloader downloader3 = getDownloaderAt(3);
+    downloader3.assertId(ID2);
+    downloader3.assertRemoveStarted();
+    downloader3.finish();
+    assertRemoved(ID2);
+
+    downloadManagerListener.blockUntilIdleAndThrowAnyFailure();
+  }
+
   private void setupDownloadManager(int maxParallelDownloads) throws Exception {
     if (downloadManager != null) {
       releaseDownloadManager();