Merge "[Magnifier-86] Fix deadlock causing ANR" into qt-dev

core/java/android/widget/Magnifier.java

@@ -136,6 +136,8 @@ public final class Magnifier {
     // Lock to synchronize between the UI thread and the thread that handles pixel copy results.
     // Only sync mWindow writes from UI thread with mWindow reads from sPixelCopyHandlerThread.
     private final Object mLock = new Object();
+    // The lock used to synchronize the UI and render threads when a #dismiss is performed.
+    private final Object mDestroyLock = new Object();
 
     /**
      * Initializes a magnifier.
@@ -275,7 +277,7 @@ public final class Magnifier {
                             mWindowElevation, mWindowCornerRadius,
                             mOverlay != null ? mOverlay : new ColorDrawable(Color.TRANSPARENT),
                             Handler.getMain() /* draw the magnifier on the UI thread */, mLock,
-                            mCallback);
+                            mDestroyLock, mCallback);
                 }
             }
             performPixelCopy(startX, startY, true /* update window position */);
@@ -304,9 +306,11 @@ public final class Magnifier {
      */
     public void dismiss() {
         if (mWindow != null) {
-            synchronized (mLock) {
-                mWindow.destroy();
-                mWindow = null;
+            synchronized (mDestroyLock) {
+                synchronized (mLock) {
+                    mWindow.destroy();
+                    mWindow = null;
+                }
             }
             mPrevShowSourceCoords.x = NONEXISTENT_PREVIOUS_CONFIG_VALUE;
             mPrevShowSourceCoords.y = NONEXISTENT_PREVIOUS_CONFIG_VALUE;
@@ -835,7 +839,7 @@ public final class Magnifier {
         // is performed on the UI thread and a frame callback on the render thread.
         // When both mLock and mDestroyLock need to be held at the same time,
         // mDestroyLock should be acquired before mLock in order to avoid deadlocks.
-        private final Object mDestroyLock = new Object();
+        private final Object mDestroyLock;
 
         // The current content of the magnifier. It is mBitmap + mOverlay, only used for testing.
         private Bitmap mCurrentContent;
@@ -843,10 +847,12 @@ public final class Magnifier {
         InternalPopupWindow(final Context context, final Display display,
                 final SurfaceControl parentSurfaceControl, final int width, final int height,
                 final float elevation, final float cornerRadius, final Drawable overlay,
-                final Handler handler, final Object lock, final Callback callback) {
+                final Handler handler, final Object lock, final Object destroyLock,
+                final Callback callback) {
             mDisplay = display;
             mOverlay = overlay;
             mLock = lock;
+            mDestroyLock = destroyLock;
             mCallback = callback;
 
             mContentWidth = width;