AudioTrack::flush() will no longer flush later data
Bug: 17832076
Change-Id: I4915d782acb8077923e419406b0dcea5b6aab961
diff --git a/media/libmedia/AudioTrackShared.cpp b/media/libmedia/AudioTrackShared.cpp
index eec025e..561cb24 100644
--- a/media/libmedia/AudioTrackShared.cpp
+++ b/media/libmedia/AudioTrackShared.cpp
@@ -348,7 +348,13 @@
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 @@
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 @@
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