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Commit b0163c6d authored by Glenn Kasten's avatar Glenn Kasten Committed by android-build-merger
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AudioTrack::flush() will no longer flush later data 

automerge: 20f51b1e

* commit '20f51b1e':
  AudioTrack::flush() will no longer flush later data
parents 2d1f309c 20f51b1e

media/libmedia/AudioTrackShared.cpp

+22 −5
Original line number Diff line number Diff line
@@ -348,7 +348,13 @@ size_t ClientProxy::getFramesFilled() { 


void AudioTrackClientProxy::flush()

{

    mCblk->u.mStreaming.mFlush++;

    // This works for mFrameCountP2 <= 2^30

    size_t increment = mFrameCountP2 << 1;

    size_t mask = increment - 1;

    audio_track_cblk_t* cblk = mCblk;

    int32_t newFlush = (cblk->u.mStreaming.mRear & mask) |

                        ((cblk->u.mStreaming.mFlush & ~mask) + increment);

    android_atomic_release_store(newFlush, &cblk->u.mStreaming.mFlush);

}



bool AudioTrackClientProxy::clearStreamEndDone() {
@@ -536,17 +542,27 @@ status_t ServerProxy::obtainBuffer(Buffer* buffer, bool ackFlush) 
        rear = android_atomic_acquire_load(&cblk->u.mStreaming.mRear);

        front = cblk->u.mStreaming.mFront;

        if (flush != mFlush) {

            mFlush = flush;

            // effectively obtain then release whatever is in the buffer

            android_atomic_release_store(rear, &cblk->u.mStreaming.mFront);

            if (front != rear) {

            size_t mask = (mFrameCountP2 << 1) - 1;

            int32_t newFront = (front & ~mask) | (flush & mask);

            ssize_t filled = rear - newFront;

            // Rather than shutting down on a corrupt flush, just treat it as a full flush

            if (!(0 <= filled && (size_t) filled <= mFrameCount)) {

                ALOGE("mFlush %#x -> %#x, front %#x, rear %#x, mask %#x, newFront %#x, filled %d=%#x",

                        mFlush, flush, front, rear, mask, newFront, filled, filled);

                newFront = rear;

            }

            mFlush = flush;

            android_atomic_release_store(newFront, &cblk->u.mStreaming.mFront);

            // There is no danger from a false positive, so err on the side of caution

            if (true /*front != newFront*/) {

                int32_t old = android_atomic_or(CBLK_FUTEX_WAKE, &cblk->mFutex);

                if (!(old & CBLK_FUTEX_WAKE)) {

                    (void) syscall(__NR_futex, &cblk->mFutex,

                            mClientInServer ? FUTEX_WAKE_PRIVATE : FUTEX_WAKE, 1);

                }

            }

            front = rear;

            front = newFront;

        }

    } else {

        front = android_atomic_acquire_load(&cblk->u.mStreaming.mFront);
@@ -668,6 +684,7 @@ size_t AudioTrackServerProxy::framesReady() 


    int32_t flush = cblk->u.mStreaming.mFlush;

    if (flush != mFlush) {

        // FIXME should return an accurate value, but over-estimate is better than under-estimate

        return mFrameCount;

    }

    // the acquire might not be necessary since not doing a subsequent read