commit 7b3c8ddea7d6e725d0a1b64fdeae35f940836974
author Evan Rosky <erosky@google.com> Thu Aug 17 09:02:16 2023 -0700
committer Evan Rosky <erosky@google.com> Fri Aug 18 07:51:17 2023 +0000
tree 5b40da3a804f39cfc17183048c0bb620086839f8
parent df13d6f717ac4bc64a989e913a02f23ba78e53d9

Only set SYNC flag if >1 track

While technically it's true that a transition is sync
if another is running in the same track, tracks already
imply sync between their constituents, so it's redundant.
The player also interprets SYNC as "stop everything
immediately" which isn't actually useful unless there are
multiple active tracks.

So, only set the sync flag when there are >1 tracks.

Bug: 296242449
Test: atest TransitionTests#testNoSyncFlagIfOneTrack
Change-Id: I61d97542825627beba4dbfa77f1cff0cf1e86ab8

services/core/java/com/android/server/wm/TransitionController.java

diff --git a/services/core/java/com/android/server/wm/TransitionController.java b/services/core/java/com/android/server/wm/TransitionController.java
index 48cca32..5b466a0 100644
--- a/services/core/java/com/android/server/wm/TransitionController.java
+++ b/services/core/java/com/android/server/wm/TransitionController.java
@@ -1124,14 +1124,15 @@
                         + "track #%d", transition.getSyncId(), track);
             }
         }
-        if (sync) {
+        transition.mAnimationTrack = track;
+        info.setTrack(track);
+        mTrackCount = Math.max(mTrackCount, track + 1);
+        if (sync && mTrackCount > 1) {
+            // If there are >1 tracks, mark as sync so that all tracks finish.
             info.setFlags(info.getFlags() | TransitionInfo.FLAG_SYNC);
             ProtoLog.v(ProtoLogGroup.WM_DEBUG_WINDOW_TRANSITIONS, "Marking #%d animation as SYNC.",
                     transition.getSyncId());
         }
-        transition.mAnimationTrack = track;
-        info.setTrack(track);
-        mTrackCount = Math.max(mTrackCount, track + 1);
     }
 
     void updateAnimatingState(SurfaceControl.Transaction t) {

services/tests/wmtests/src/com/android/server/wm/TransitionTests.java

diff --git a/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java b/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java
index b4f1176..d7cd9f2 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TransitionTests.java
@@ -39,6 +39,7 @@
 import static android.window.TransitionInfo.FLAG_IS_WALLPAPER;
 import static android.window.TransitionInfo.FLAG_MOVED_TO_TOP;
 import static android.window.TransitionInfo.FLAG_SHOW_WALLPAPER;
+import static android.window.TransitionInfo.FLAG_SYNC;
 import static android.window.TransitionInfo.FLAG_TRANSLUCENT;
 import static android.window.TransitionInfo.isIndependent;
 
@@ -2384,6 +2385,37 @@
         assertFalse(controller.isCollecting());
     }
 
+    @Test
+    public void testNoSyncFlagIfOneTrack() {
+        final TransitionController controller = mAtm.getTransitionController();
+        final TestTransitionPlayer player = registerTestTransitionPlayer();
+
+        mSyncEngine = createTestBLASTSyncEngine();
+        controller.setSyncEngine(mSyncEngine);
+
+        final Transition transitA = createTestTransition(TRANSIT_OPEN, controller);
+        final Transition transitB = createTestTransition(TRANSIT_OPEN, controller);
+        final Transition transitC = createTestTransition(TRANSIT_OPEN, controller);
+
+        controller.startCollectOrQueue(transitA, (deferred) -> {});
+        controller.startCollectOrQueue(transitB, (deferred) -> {});
+        controller.startCollectOrQueue(transitC, (deferred) -> {});
+
+        // Verify that, as-long as there is <= 1 track, we won't get a SYNC flag
+        transitA.start();
+        transitA.setAllReady();
+        mSyncEngine.tryFinishForTest(transitA.getSyncId());
+        assertTrue((player.mLastReady.getFlags() & FLAG_SYNC) == 0);
+        transitB.start();
+        transitB.setAllReady();
+        mSyncEngine.tryFinishForTest(transitB.getSyncId());
+        assertTrue((player.mLastReady.getFlags() & FLAG_SYNC) == 0);
+        transitC.start();
+        transitC.setAllReady();
+        mSyncEngine.tryFinishForTest(transitC.getSyncId());
+        assertTrue((player.mLastReady.getFlags() & FLAG_SYNC) == 0);
+    }
+
     private static void makeTaskOrganized(Task... tasks) {
         final ITaskOrganizer organizer = mock(ITaskOrganizer.class);
         for (Task t : tasks) {