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Commit 80615b00 authored by Adam Powell's avatar Adam Powell
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Fix bug 4080407 - Browser stuck after scrolling- page stops responding 

Account for gaps in touch queue sequence numbering when we flush out
canceled events from webcore's queue. Add a 2-second timeout to auto-flush
old events when a new gesture begins.

Change-Id: I764a7fcd673b3afb629055b001e9346f5b959dba
parent 0837fde9

core/java/android/webkit/WebView.java

+59 −0
Original line number Diff line number Diff line
@@ -6019,6 +6019,7 @@ public class WebView extends AbsoluteLayout 
        if (shouldForwardTouchEvent()) {

            if (removeEvents) {

                mWebViewCore.removeMessages(EventHub.TOUCH_EVENT);

                mTouchEventQueue.ignoreCurrentlyMissingEvents();

            }

            TouchEventData ted = new TouchEventData();

            ted.mIds = new int[1];
@@ -7157,11 +7158,15 @@ public class WebView extends AbsoluteLayout 
    private class TouchEventQueue {

        private long mNextTouchSequence = Long.MIN_VALUE + 1;

        private long mLastHandledTouchSequence = Long.MIN_VALUE;

        private long mIgnoreUntilSequence = Long.MIN_VALUE;

        private QueuedTouch mTouchEventQueue;

        private QueuedTouch mQueuedTouchRecycleBin;

        private int mQueuedTouchRecycleCount;

        private static final int MAX_RECYCLED_QUEUED_TOUCH = 15;



        // milliseconds until we abandon hope of getting all of a previous gesture

        private static final int QUEUED_GESTURE_TIMEOUT = 2000;



        private QueuedTouch obtainQueuedTouch() {

            if (mQueuedTouchRecycleBin != null) {

                QueuedTouch result = mQueuedTouchRecycleBin;
@@ -7172,6 +7177,13 @@ public class WebView extends AbsoluteLayout 
            return new QueuedTouch();

        }



        /**

         * Allow events with any currently missing sequence numbers to be skipped in processing.

         */

        public void ignoreCurrentlyMissingEvents() {

            mIgnoreUntilSequence = mNextTouchSequence;

        }



        private void recycleQueuedTouch(QueuedTouch qd) {

            if (mQueuedTouchRecycleCount < MAX_RECYCLED_QUEUED_TOUCH) {

                qd.mNext = mQueuedTouchRecycleBin;
@@ -7187,6 +7199,7 @@ public class WebView extends AbsoluteLayout 
        public void reset() {

            mNextTouchSequence = Long.MIN_VALUE + 1;

            mLastHandledTouchSequence = Long.MIN_VALUE;

            mIgnoreUntilSequence = Long.MIN_VALUE;

            while (mTouchEventQueue != null) {

                QueuedTouch recycleMe = mTouchEventQueue;

                mTouchEventQueue = mTouchEventQueue.mNext;
@@ -7213,6 +7226,15 @@ public class WebView extends AbsoluteLayout 
         * @param ted Touch data to be processed in order.

         */

        public void enqueueTouchEvent(TouchEventData ted) {

            if (ted.mSequence < mLastHandledTouchSequence) {

                // Stale event and we already moved on; drop it. (Should not be common.)

                Log.w(LOGTAG, "Stale touch event " + MotionEvent.actionToString(ted.mAction) +

                        " received from webcore; ignoring");

                return;

            }



            dropStaleGestures(ted.mMotionEvent, ted.mSequence);



            if (mLastHandledTouchSequence + 1 == ted.mSequence) {

                handleQueuedTouchEventData(ted);
@@ -7245,6 +7267,9 @@ public class WebView extends AbsoluteLayout 
         */

        public void enqueueTouchEvent(MotionEvent ev) {

            final long sequence = nextTouchSequence();



            dropStaleGestures(ev, sequence);



            if (mLastHandledTouchSequence + 1 == sequence) {

                handleQueuedMotionEvent(ev);
@@ -7266,6 +7291,40 @@ public class WebView extends AbsoluteLayout 
            }

        }



        private void dropStaleGestures(MotionEvent ev, long sequence) {

            if (ev != null && ev.getAction() == MotionEvent.ACTION_DOWN &&

                    mTouchEventQueue != null) {

                long eventTime = ev.getEventTime();

                long nextQueueTime = mTouchEventQueue.mTed != null ?

                        mTouchEventQueue.mTed.mMotionEvent.getEventTime() :

                        mTouchEventQueue.mEvent.getEventTime();

                if (eventTime > nextQueueTime + QUEUED_GESTURE_TIMEOUT) {

                    Log.w(LOGTAG, "Got ACTION_DOWN but still waiting on stale event. " +

                            "Ignoring previous queued events.");

                    QueuedTouch qd = mTouchEventQueue;

                    while (qd != null && qd.mSequence < sequence) {

                        QueuedTouch recycleMe = qd;

                        qd = qd.mNext;

                        recycleQueuedTouch(recycleMe);

                    }

                    mTouchEventQueue = qd;

                    mLastHandledTouchSequence = sequence - 1;

                }

            }



            if (mIgnoreUntilSequence > mLastHandledTouchSequence) {

                QueuedTouch qd = mTouchEventQueue;

                while (qd != null && qd.mSequence < mIgnoreUntilSequence &&

                        qd.mSequence < sequence) {

                    mLastHandledTouchSequence = qd.mSequence;

                    QueuedTouch recycleMe = qd;

                    qd = qd.mNext;

                    recycleQueuedTouch(recycleMe);

                }

                mTouchEventQueue = qd;

            }

        }



        private void handleQueuedTouch(QueuedTouch qt) {

            if (qt.mTed != null) {

                handleQueuedTouchEventData(qt.mTed);