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Commit a93fcc9e authored by Robert Carr's avatar Robert Carr
Browse files

ViewRootImpl: Fix issue with early draw report in seamless rotation 

When we receive RELAYOUT_RES_BLAST_SYNC from the WindowManager, we
trigger reportNextDraw, incrementing the pending draw count by one.
At the moment we unfortunately do this after dispatching callbacks
to SurfaceView. In the span of these callbacks, SurfaceView may
increment and decrement pending draw count, once it reaches zero
we will notify the WM of draw early, terminating the sync operation
without ever waiting for the ViewRootImpl to draw. By processing
RELAYOUT_RES_BLAST_SYNC before emitting the SurfaceView callbacks
we can avoid this issue.

Bug: 191921061
Test: Existing tests pass
Change-Id: I2f1096c9cdc79b89413c3f0bfd9b3054ef45f2d2
parent 74c65d26

core/java/android/view/ViewRootImpl.java

+22 −14
Original line number Diff line number Diff line
@@ -2771,6 +2771,7 @@ public final class ViewRootImpl implements ViewParent, 
                mView.onSystemBarAppearanceChanged(mDispatchedSystemBarAppearance);

            }

        }

        final boolean wasReportNextDraw = mReportNextDraw;



        if (mFirst || windowShouldResize || viewVisibilityChanged || params != null

                || mForceNextWindowRelayout) {
@@ -2817,6 +2818,16 @@ public final class ViewRootImpl implements ViewParent, 
                final boolean dockedResizing = (relayoutResult

                        & WindowManagerGlobal.RELAYOUT_RES_DRAG_RESIZING_DOCKED) != 0;

                final boolean dragResizing = freeformResizing || dockedResizing;

                if ((relayoutResult & WindowManagerGlobal.RELAYOUT_RES_BLAST_SYNC) != 0) {

                    if (DEBUG_BLAST) {

                        Log.d(mTag, "Relayout called with blastSync");

                    }

                    reportNextDraw();

                    if (isHardwareEnabled()) {

                        mNextDrawUseBlastSync = true;

                    }

                }



                if (mSurfaceControl.isValid()) {

                    updateOpacity(mWindowAttributes, dragResizing);

                }
@@ -3035,7 +3046,16 @@ public final class ViewRootImpl implements ViewParent, 
                }

            }



            if (!mStopped || mReportNextDraw) {

            // TODO: In the CL "ViewRootImpl: Fix issue with early draw report in

            // seamless rotation". We moved processing of RELAYOUT_RES_BLAST_SYNC

            // earlier in the function, potentially triggering a call to

            // reportNextDraw(). That same CL changed this and the next reference

            // to wasReportNextDraw, such that this logic would remain undisturbed

            // (it continues to operate as if the code was never moved). This was

            // done to achieve a more hermetic fix for S, but it's entirely

            // possible that checking the most recent value is actually more

            // correct here.

            if (!mStopped || wasReportNextDraw) {

                boolean focusChangedDueToTouchMode = ensureTouchModeLocally(

                        (relayoutResult&WindowManagerGlobal.RELAYOUT_RES_IN_TOUCH_MODE) != 0);

                if (focusChangedDueToTouchMode || mWidth != host.getMeasuredWidth()
@@ -3105,7 +3125,7 @@ public final class ViewRootImpl implements ViewParent, 
            prepareSurfaces();

        }



        final boolean didLayout = layoutRequested && (!mStopped || mReportNextDraw);

        final boolean didLayout = layoutRequested && (!mStopped || wasReportNextDraw);

        boolean triggerGlobalLayoutListener = didLayout

                || mAttachInfo.mRecomputeGlobalAttributes;

        if (didLayout) {
@@ -3261,21 +3281,10 @@ public final class ViewRootImpl implements ViewParent, 


        mImeFocusController.onTraversal(hasWindowFocus, mWindowAttributes);



        final boolean wasReportNextDraw = mReportNextDraw;



        // Remember if we must report the next draw.

        if ((relayoutResult & WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) {

            reportNextDraw();

        }

        if ((relayoutResult & WindowManagerGlobal.RELAYOUT_RES_BLAST_SYNC) != 0) {

            if (DEBUG_BLAST) {

                Log.d(mTag, "Relayout called with blastSync");

            }

            reportNextDraw();

            if (isHardwareEnabled()) {

                mNextDrawUseBlastSync = true;

            }

        }



        boolean cancelDraw = mAttachInfo.mTreeObserver.dispatchOnPreDraw() || !isViewVisible;
@@ -3286,7 +3295,6 @@ public final class ViewRootImpl implements ViewParent, 
                }

                mPendingTransitions.clear();

            }



            performDraw();

        } else {

            if (isViewVisible) {