Merge "DO NOT MERGE: ViewRootImpl: Add P2P sync primitive" into sc-v2-dev (eba32bb2) · Commits · e / os / android_frameworks_base

core/java/android/view/ViewRootImpl.java

+42 −0

Original line number	Diff line number	Diff line
		@@ -208,6 +208,7 @@ import java.io.PrintWriter;
		import java.io.StringWriter;
		import java.lang.ref.WeakReference;
		import java.util.ArrayList;
		import java.util.function.Consumer;
		import java.util.HashSet;
		import java.util.LinkedList;
		import java.util.List;
		@@ -757,6 +758,8 @@ public final class ViewRootImpl implements ViewParent,
		*/
		private boolean mNextDrawUseBlastSync = false;

		private Consumer<SurfaceControl.Transaction> mBLASTDrawConsumer;

		/**
		* Wait for the blast sync transaction complete callback before drawing and queuing up more
		* frames. This will prevent out of order buffers submissions when WM has requested to
		@@ -3351,6 +3354,9 @@ public final class ViewRootImpl implements ViewParent,
		}

		boolean cancelDraw = mAttachInfo.mTreeObserver.dispatchOnPreDraw() \|\| !isViewVisible;
		if (mBLASTDrawConsumer != null) {
		mNextDrawUseBlastSync = true;
		}

		if (!cancelDraw) {
		if (mPendingTransitions != null && mPendingTransitions.size() > 0) {
		@@ -4049,6 +4055,8 @@ public final class ViewRootImpl implements ViewParent,
		*/
		private HardwareRenderer.FrameCompleteCallback createFrameCompleteCallback(Handler handler,
		boolean reportNextDraw, ArrayList<Runnable> commitCallbacks) {
		final Consumer<SurfaceControl.Transaction> blastSyncConsumer = mBLASTDrawConsumer;
		mBLASTDrawConsumer = null;
		return frameNr -> {
		if (DEBUG_BLAST) {
		Log.d(mTag, "Received frameCompleteCallback frameNum=" + frameNr);
		@@ -4061,6 +4069,9 @@ public final class ViewRootImpl implements ViewParent,
		// is only true when the UI thread is paused. Therefore, no one should be
		// modifying this object until the next vsync.
		mSurfaceChangedTransaction.merge(mRtBLASTSyncTransaction);
		if (blastSyncConsumer != null) {
		blastSyncConsumer.accept(mSurfaceChangedTransaction);
		}
		}

		if (reportNextDraw) {
		@@ -10550,4 +10561,35 @@ public final class ViewRootImpl implements ViewParent,
		listener.onBufferTransformHintChanged(hint);
		}
		}

		/**
		* Redirect the next draw of this ViewRoot (from the UI thread perspective)
		* to the passed in consumer. This can be used to create P2P synchronization
		* between ViewRoot's however it comes with many caveats.
		*
		* 1. You MUST consume the transaction, by either applying it immediately or
		* merging it in to another transaction. The threading model doesn't
		* allow you to hold in the passed transaction.
		* 2. If you merge it in to another transaction, this ViewRootImpl will be
		* paused until you finally apply that transaction and it receives
		* the callback from SF. If you lose track of the transaction you will
		* ANR the app.
		* 3. Only one person can consume the transaction at a time, if you already
		* have a pending consumer for this frame, the function will return false
		* 4. Someone else may have requested to consume the next frame, in which case
		* this function will return false and you will not receive a callback.
		* 5. This function does not trigger drawing so even if it returns true you
		* may not receive a callback unless there is some other UI thread work
		* to trigger drawing. If it returns true, and a draw occurs, the callback
		* will be called (Though again watch out for the null transaction case!)
		* 6. This function must be called on the UI thread. The consumer will likewise
		* be called on the UI thread.
		*/
		public boolean consumeNextDraw(Consumer<SurfaceControl.Transaction> consume) {
		if (mBLASTDrawConsumer != null) {
		return false;
		}
		mBLASTDrawConsumer = consume;
		return true;
		}
		}