commit ed6794ece553f42e9f17099e9eaf7f62966f3ac6
author Tiger Huang <tigerhuang@google.com> Tue May 07 20:07:59 2019 +0800
committer Tiger Huang <tigerhuang@google.com> Mon May 13 20:38:32 2019 +0800
tree d2e637bf2f9080fe7580f7a9ca8a25112c84eefd
parent 4d5b76d33b32daa197fee18a91371aa461448153

Fix a bug about the z-order of layers caused by merging transactions

Each WindowContainer has its own pending transaction. These transactions
may be merged to the global one within WindowContainer.prepareSurfaces()
in a hierarchy-based order, not in a time-based order. It may cause
that a later surface operation overwritten by an earlier surface
operation. For example, atokenA.setLayer(t1, 0) was called earlier, and
then atokenA.setLayer(t2, 1) was called later. However, the layer of
atokenA might eventually be 0 because t1 could be merged into the
global transaction later.

This CL uses a single transaction per display to solve this problem.

Fix: 120282809
Test: atest SurfaceAnimatorTest
Test: Manual test with the steps in the issue.
Change-Id: Idca57d01d8be884369510642c2d9345b6ee4e3b1

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

diff --git a/services/core/java/com/android/server/wm/AppWindowToken.java b/services/core/java/com/android/server/wm/AppWindowToken.java
index fd90f03..ecbecba 100644
--- a/services/core/java/com/android/server/wm/AppWindowToken.java
+++ b/services/core/java/com/android/server/wm/AppWindowToken.java
@@ -2005,7 +2005,7 @@
         }
         layoutLetterbox(winHint);
         if (mLetterbox != null && mLetterbox.needsApplySurfaceChanges()) {
-            mLetterbox.applySurfaceChanges(mPendingTransaction);
+            mLetterbox.applySurfaceChanges(getPendingTransaction());
         }
     }
 
@@ -3059,13 +3059,13 @@
 
         if (mSurfaceControl != null) {
             if (show && !mLastSurfaceShowing) {
-                mPendingTransaction.show(mSurfaceControl);
+                getPendingTransaction().show(mSurfaceControl);
             } else if (!show && mLastSurfaceShowing) {
-                mPendingTransaction.hide(mSurfaceControl);
+                getPendingTransaction().hide(mSurfaceControl);
             }
         }
         if (mThumbnail != null) {
-            mThumbnail.setShowing(mPendingTransaction, show);
+            mThumbnail.setShowing(getPendingTransaction(), show);
         }
         mLastSurfaceShowing = show;
         super.prepareSurfaces();
@@ -3225,8 +3225,8 @@
 
     private void updateColorTransform() {
         if (mSurfaceControl != null && mLastAppSaturationInfo != null) {
-            mPendingTransaction.setColorTransform(mSurfaceControl, mLastAppSaturationInfo.mMatrix,
-                    mLastAppSaturationInfo.mTranslation);
+            getPendingTransaction().setColorTransform(mSurfaceControl,
+                    mLastAppSaturationInfo.mMatrix, mLastAppSaturationInfo.mTranslation);
             mWmService.scheduleAnimationLocked();
         }
     }