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Commit eb30074f authored by Kean Mariotti's avatar Kean Mariotti
Browse files

Revert "viewcapture: guarantee happens-before relationship" 

This reverts commit 762ac978.

Turns out the issue was concurrent onDraw calls from multiple
UI threads instead. Mitigation in follow up CL.

Bug: 375005884
Flag: EXEMPT minor revert
Test: n/a
Change-Id: Ida113470ddfb27bce7f41ec9e6614a254ff9ca1c
parent 8bc864a4

viewcapturelib/src/com/android/app/viewcapture/ViewCapture.java

+4 −12
Original line number Diff line number Diff line
@@ -311,12 +311,8 @@ public abstract class ViewCapture { 
            captureViewTree(mRoot, mViewPropertyRef);

            ViewPropertyRef captured = mViewPropertyRef.next;

            if (captured != null) {

                captured.callback = mCaptureCallback;

                captured.elapsedRealtimeNanos = SystemClock.elapsedRealtimeNanos();



                // Main thread writes volatile field:

                // guarantee that variable changes prior the field write are visible to bg thread

                captured.volatileCallback = mCaptureCallback;



                mBgExecutor.execute(captured);

            }

            mIsFirstFrame = false;
@@ -556,11 +552,9 @@ public abstract class ViewCapture { 


        public ViewPropertyRef next;



        public Consumer<ViewPropertyRef> callback = null;

        public long elapsedRealtimeNanos = 0;



        // Volatile field to establish happens-before relationship between main and bg threads

        // (see JSR-133: Java Memory Model and Thread Specification)

        public volatile Consumer<ViewPropertyRef> volatileCallback = null;



        public void transferFrom(View in) {

            view = in;
@@ -657,10 +651,8 @@ public abstract class ViewCapture { 


        @Override

        public void run() {

            // Bg thread reads volatile field:

            // guarantee that variable changes in main thread prior the field write are visible

            Consumer<ViewPropertyRef> oldCallback = volatileCallback;

            volatileCallback = null;

            Consumer<ViewPropertyRef> oldCallback = callback;

            callback = null;

            if (oldCallback != null) {

                oldCallback.accept(this);

            }