New control block for AudioTrack and AudioRecord
Main differences between old and new control block:
- removes the mutex, which was a potential source of priority inversion
- circular indices into shared buffer, which is now always a power-of-2 size
Change-Id: I4e9b7fa99858b488ac98a441fa70e31dbba1b865
diff --git a/media/libmedia/AudioTrackShared.cpp b/media/libmedia/AudioTrackShared.cpp
index 13d47c9..f034164 100644
--- a/media/libmedia/AudioTrackShared.cpp
+++ b/media/libmedia/AudioTrackShared.cpp
@@ -19,178 +19,664 @@
#include <private/media/AudioTrackShared.h>
#include <utils/Log.h>
+extern "C" {
+#include "../private/bionic_futex.h"
+}
namespace android {
audio_track_cblk_t::audio_track_cblk_t()
- : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
- userBase(0), serverBase(0), frameCount_(0),
- loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), mVolumeLR(0x10001000),
- mSampleRate(0), mSendLevel(0), flags(0)
+ : server(0), frameCount_(0), mFutex(0), mMinimum(0),
+ mVolumeLR(0x10001000), mSampleRate(0), mSendLevel(0), mName(0), flags(0)
+{
+ memset(&u, 0, sizeof(u));
+}
+
+// ---------------------------------------------------------------------------
+
+Proxy::Proxy(audio_track_cblk_t* cblk, void *buffers, size_t frameCount, size_t frameSize,
+ bool isOut, bool clientInServer)
+ : mCblk(cblk), mBuffers(buffers), mFrameCount(frameCount), mFrameSize(frameSize),
+ mFrameCountP2(roundup(frameCount)), mIsOut(isOut), mClientInServer(clientInServer),
+ mIsShutdown(false)
{
}
-uint32_t audio_track_cblk_t::stepUser(size_t stepCount, size_t frameCount, bool isOut)
+// ---------------------------------------------------------------------------
+
+ClientProxy::ClientProxy(audio_track_cblk_t* cblk, void *buffers, size_t frameCount,
+ size_t frameSize, bool isOut, bool clientInServer)
+ : Proxy(cblk, buffers, frameCount, frameSize, isOut, clientInServer), mEpoch(0)
{
- ALOGV("stepuser %08x %08x %d", user, server, stepCount);
-
- uint32_t u = user;
- u += stepCount;
- // Ensure that user is never ahead of server for AudioRecord
- if (isOut) {
- // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
- if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
- bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
- }
- } else if (u > server) {
- ALOGW("stepUser occurred after track reset");
- u = server;
- }
-
- if (u >= frameCount) {
- // common case, user didn't just wrap
- if (u - frameCount >= userBase ) {
- userBase += frameCount;
- }
- } else if (u >= userBase + frameCount) {
- // user just wrapped
- userBase += frameCount;
- }
-
- user = u;
-
- // Clear flow control error condition as new data has been written/read to/from buffer.
- if (flags & CBLK_UNDERRUN) {
- android_atomic_and(~CBLK_UNDERRUN, &flags);
- }
-
- return u;
}
-bool audio_track_cblk_t::stepServer(size_t stepCount, size_t frameCount, bool isOut)
+const struct timespec ClientProxy::kForever = {INT_MAX /*tv_sec*/, 0 /*tv_nsec*/};
+const struct timespec ClientProxy::kNonBlocking = {0 /*tv_sec*/, 0 /*tv_nsec*/};
+
+#define MEASURE_NS 10000000 // attempt to provide accurate timeouts if requested >= MEASURE_NS
+
+// To facilitate quicker recovery from server failure, this value limits the timeout per each futex
+// wait. However it does not protect infinite timeouts. If defined to be zero, there is no limit.
+// FIXME May not be compatible with audio tunneling requirements where timeout should be in the
+// order of minutes.
+#define MAX_SEC 5
+
+status_t ClientProxy::obtainBuffer(Buffer* buffer, const struct timespec *requested,
+ struct timespec *elapsed)
{
- ALOGV("stepserver %08x %08x %d", user, server, stepCount);
-
- if (!tryLock()) {
- ALOGW("stepServer() could not lock cblk");
- return false;
+ if (buffer == NULL || buffer->mFrameCount == 0) {
+ ALOGE("%s BAD_VALUE", __func__);
+ return BAD_VALUE;
}
+ struct timespec total; // total elapsed time spent waiting
+ total.tv_sec = 0;
+ total.tv_nsec = 0;
+ bool measure = elapsed != NULL; // whether to measure total elapsed time spent waiting
- uint32_t s = server;
- bool flushed = (s == user);
-
- s += stepCount;
- if (isOut) {
- // Mark that we have read the first buffer so that next time stepUser() is called
- // we switch to normal obtainBuffer() timeout period
- if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
- bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
- }
- // It is possible that we receive a flush()
- // while the mixer is processing a block: in this case,
- // stepServer() is called After the flush() has reset u & s and
- // we have s > u
- if (flushed) {
- ALOGW("stepServer occurred after track reset");
- s = user;
- }
- }
-
- if (s >= loopEnd) {
- ALOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
- s = loopStart;
- if (--loopCount == 0) {
- loopEnd = UINT_MAX;
- loopStart = UINT_MAX;
- }
- }
-
- if (s >= frameCount) {
- // common case, server didn't just wrap
- if (s - frameCount >= serverBase ) {
- serverBase += frameCount;
- }
- } else if (s >= serverBase + frameCount) {
- // server just wrapped
- serverBase += frameCount;
- }
-
- server = s;
-
- if (!(flags & CBLK_INVALID)) {
- cv.signal();
- }
- lock.unlock();
- return true;
-}
-
-void* audio_track_cblk_t::buffer(void *buffers, size_t frameSize, uint32_t offset) const
-{
- return (int8_t *)buffers + (offset - userBase) * frameSize;
-}
-
-uint32_t audio_track_cblk_t::framesAvailable(size_t frameCount, bool isOut)
-{
- Mutex::Autolock _l(lock);
- return framesAvailable_l(frameCount, isOut);
-}
-
-uint32_t audio_track_cblk_t::framesAvailable_l(size_t frameCount, bool isOut)
-{
- uint32_t u = user;
- uint32_t s = server;
-
- if (isOut) {
- uint32_t limit = (s < loopStart) ? s : loopStart;
- return limit + frameCount - u;
+ status_t status;
+ enum {
+ TIMEOUT_ZERO, // requested == NULL || *requested == 0
+ TIMEOUT_INFINITE, // *requested == infinity
+ TIMEOUT_FINITE, // 0 < *requested < infinity
+ TIMEOUT_CONTINUE, // additional chances after TIMEOUT_FINITE
+ } timeout;
+ if (requested == NULL) {
+ timeout = TIMEOUT_ZERO;
+ } else if (requested->tv_sec == 0 && requested->tv_nsec == 0) {
+ timeout = TIMEOUT_ZERO;
+ } else if (requested->tv_sec == INT_MAX) {
+ timeout = TIMEOUT_INFINITE;
} else {
- return frameCount + u - s;
+ timeout = TIMEOUT_FINITE;
+ if (requested->tv_sec > 0 || requested->tv_nsec >= MEASURE_NS) {
+ measure = true;
+ }
}
-}
-
-uint32_t audio_track_cblk_t::framesReady(bool isOut)
-{
- uint32_t u = user;
- uint32_t s = server;
-
- if (isOut) {
- if (u < loopEnd) {
- return u - s;
+ struct timespec before;
+ bool beforeIsValid = false;
+ audio_track_cblk_t* cblk = mCblk;
+ bool ignoreInitialPendingInterrupt = true;
+ // check for shared memory corruption
+ if (mIsShutdown) {
+ status = NO_INIT;
+ goto end;
+ }
+ for (;;) {
+ int32_t flags = android_atomic_and(~CBLK_INTERRUPT, &cblk->flags);
+ // check for track invalidation by server, or server death detection
+ if (flags & CBLK_INVALID) {
+ ALOGV("Track invalidated");
+ status = DEAD_OBJECT;
+ goto end;
+ }
+ // check for obtainBuffer interrupted by client
+ if (!ignoreInitialPendingInterrupt && (flags & CBLK_INTERRUPT)) {
+ ALOGV("obtainBuffer() interrupted by client");
+ status = -EINTR;
+ goto end;
+ }
+ ignoreInitialPendingInterrupt = false;
+ // compute number of frames available to write (AudioTrack) or read (AudioRecord)
+ int32_t front;
+ int32_t rear;
+ if (mIsOut) {
+ // The barrier following the read of mFront is probably redundant.
+ // We're about to perform a conditional branch based on 'filled',
+ // which will force the processor to observe the read of mFront
+ // prior to allowing data writes starting at mRaw.
+ // However, the processor may support speculative execution,
+ // and be unable to undo speculative writes into shared memory.
+ // The barrier will prevent such speculative execution.
+ front = android_atomic_acquire_load(&cblk->u.mStreaming.mFront);
+ rear = cblk->u.mStreaming.mRear;
} else {
- // do not block on mutex shared with client on AudioFlinger side
- if (!tryLock()) {
- ALOGW("framesReady() could not lock cblk");
- return 0;
+ // On the other hand, this barrier is required.
+ rear = android_atomic_acquire_load(&cblk->u.mStreaming.mRear);
+ front = cblk->u.mStreaming.mFront;
+ }
+ ssize_t filled = rear - front;
+ // pipe should not be overfull
+ if (!(0 <= filled && (size_t) filled <= mFrameCount)) {
+ ALOGE("Shared memory control block is corrupt (filled=%d); shutting down", filled);
+ mIsShutdown = true;
+ status = NO_INIT;
+ goto end;
+ }
+ // don't allow filling pipe beyond the nominal size
+ size_t avail = mIsOut ? mFrameCount - filled : filled;
+ if (avail > 0) {
+ // 'avail' may be non-contiguous, so return only the first contiguous chunk
+ size_t part1;
+ if (mIsOut) {
+ rear &= mFrameCountP2 - 1;
+ part1 = mFrameCountP2 - rear;
+ } else {
+ front &= mFrameCountP2 - 1;
+ part1 = mFrameCountP2 - front;
}
- uint32_t frames = UINT_MAX;
- if (loopCount >= 0) {
- frames = (loopEnd - loopStart)*loopCount + u - s;
+ if (part1 > avail) {
+ part1 = avail;
}
- lock.unlock();
- return frames;
+ if (part1 > buffer->mFrameCount) {
+ part1 = buffer->mFrameCount;
+ }
+ buffer->mFrameCount = part1;
+ buffer->mRaw = part1 > 0 ?
+ &((char *) mBuffers)[(mIsOut ? rear : front) * mFrameSize] : NULL;
+ buffer->mNonContig = avail - part1;
+ // mUnreleased = part1;
+ status = NO_ERROR;
+ break;
+ }
+ struct timespec remaining;
+ const struct timespec *ts;
+ switch (timeout) {
+ case TIMEOUT_ZERO:
+ status = WOULD_BLOCK;
+ goto end;
+ case TIMEOUT_INFINITE:
+ ts = NULL;
+ break;
+ case TIMEOUT_FINITE:
+ timeout = TIMEOUT_CONTINUE;
+ if (MAX_SEC == 0) {
+ ts = requested;
+ break;
+ }
+ // fall through
+ case TIMEOUT_CONTINUE:
+ // FIXME we do not retry if requested < 10ms? needs documentation on this state machine
+ if (!measure || requested->tv_sec < total.tv_sec ||
+ (requested->tv_sec == total.tv_sec && requested->tv_nsec <= total.tv_nsec)) {
+ status = TIMED_OUT;
+ goto end;
+ }
+ remaining.tv_sec = requested->tv_sec - total.tv_sec;
+ if ((remaining.tv_nsec = requested->tv_nsec - total.tv_nsec) < 0) {
+ remaining.tv_nsec += 1000000000;
+ remaining.tv_sec++;
+ }
+ if (0 < MAX_SEC && MAX_SEC < remaining.tv_sec) {
+ remaining.tv_sec = MAX_SEC;
+ remaining.tv_nsec = 0;
+ }
+ ts = &remaining;
+ break;
+ default:
+ LOG_FATAL("%s timeout=%d", timeout);
+ ts = NULL;
+ break;
+ }
+ int32_t old = android_atomic_dec(&cblk->mFutex);
+ if (old <= 0) {
+ int rc;
+ if (measure && !beforeIsValid) {
+ clock_gettime(CLOCK_MONOTONIC, &before);
+ beforeIsValid = true;
+ }
+ int ret = __futex_syscall4(&cblk->mFutex,
+ mClientInServer ? FUTEX_WAIT_PRIVATE : FUTEX_WAIT, old - 1, ts);
+ // update total elapsed time spent waiting
+ if (measure) {
+ struct timespec after;
+ clock_gettime(CLOCK_MONOTONIC, &after);
+ total.tv_sec += after.tv_sec - before.tv_sec;
+ long deltaNs = after.tv_nsec - before.tv_nsec;
+ if (deltaNs < 0) {
+ deltaNs += 1000000000;
+ total.tv_sec--;
+ }
+ if ((total.tv_nsec += deltaNs) >= 1000000000) {
+ total.tv_nsec -= 1000000000;
+ total.tv_sec++;
+ }
+ before = after;
+ beforeIsValid = true;
+ }
+ switch (ret) {
+ case 0: // normal wakeup by server, or by binderDied()
+ case -EWOULDBLOCK: // benign race condition with server
+ case -EINTR: // wait was interrupted by signal or other spurious wakeup
+ case -ETIMEDOUT: // time-out expired
+ break;
+ default:
+ ALOGE("%s unexpected error %d", __func__, ret);
+ status = -ret;
+ goto end;
+ }
+ }
+ }
+
+end:
+ if (status != NO_ERROR) {
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ }
+ if (elapsed != NULL) {
+ *elapsed = total;
+ }
+ if (requested == NULL) {
+ requested = &kNonBlocking;
+ }
+ if (measure) {
+ ALOGV("requested %d.%03d elapsed %d.%03d", requested->tv_sec, requested->tv_nsec / 1000000,
+ total.tv_sec, total.tv_nsec / 1000000);
+ }
+ return status;
+}
+
+void ClientProxy::releaseBuffer(Buffer* buffer)
+{
+ size_t stepCount = buffer->mFrameCount;
+ // FIXME
+ // check mUnreleased
+ // verify that stepCount <= frameCount returned by the last obtainBuffer()
+ // verify stepCount not > total frame count of pipe
+ if (stepCount == 0) {
+ return;
+ }
+ audio_track_cblk_t* cblk = mCblk;
+ // Both of these barriers are required
+ if (mIsOut) {
+ int32_t rear = cblk->u.mStreaming.mRear;
+ android_atomic_release_store(stepCount + rear, &cblk->u.mStreaming.mRear);
+ } else {
+ int32_t front = cblk->u.mStreaming.mFront;
+ android_atomic_release_store(stepCount + front, &cblk->u.mStreaming.mFront);
+ }
+}
+
+void ClientProxy::binderDied()
+{
+ audio_track_cblk_t* cblk = mCblk;
+ if (!(android_atomic_or(CBLK_INVALID, &cblk->flags) & CBLK_INVALID)) {
+ // it seems that a FUTEX_WAKE_PRIVATE will not wake a FUTEX_WAIT, even within same process
+ (void) __futex_syscall3(&cblk->mFutex, mClientInServer ? FUTEX_WAKE_PRIVATE : FUTEX_WAKE,
+ 1);
+ }
+}
+
+void ClientProxy::interrupt()
+{
+ audio_track_cblk_t* cblk = mCblk;
+ if (!(android_atomic_or(CBLK_INTERRUPT, &cblk->flags) & CBLK_INTERRUPT)) {
+ (void) __futex_syscall3(&cblk->mFutex, mClientInServer ? FUTEX_WAKE_PRIVATE : FUTEX_WAKE,
+ 1);
+ }
+}
+
+size_t ClientProxy::getMisalignment()
+{
+ audio_track_cblk_t* cblk = mCblk;
+ return (mFrameCountP2 - (mIsOut ? cblk->u.mStreaming.mRear : cblk->u.mStreaming.mFront)) &
+ (mFrameCountP2 - 1);
+}
+
+// ---------------------------------------------------------------------------
+
+void AudioTrackClientProxy::flush()
+{
+ mCblk->u.mStreaming.mFlush++;
+}
+
+// ---------------------------------------------------------------------------
+
+StaticAudioTrackClientProxy::StaticAudioTrackClientProxy(audio_track_cblk_t* cblk, void *buffers,
+ size_t frameCount, size_t frameSize)
+ : AudioTrackClientProxy(cblk, buffers, frameCount, frameSize),
+ mMutator(&cblk->u.mStatic.mSingleStateQueue), mBufferPosition(0)
+{
+}
+
+void StaticAudioTrackClientProxy::flush()
+{
+ LOG_FATAL("static flush");
+}
+
+void StaticAudioTrackClientProxy::setLoop(size_t loopStart, size_t loopEnd, int loopCount)
+{
+ StaticAudioTrackState newState;
+ newState.mLoopStart = loopStart;
+ newState.mLoopEnd = loopEnd;
+ newState.mLoopCount = loopCount;
+ mBufferPosition = loopStart;
+ (void) mMutator.push(newState);
+}
+
+size_t StaticAudioTrackClientProxy::getBufferPosition()
+{
+ size_t bufferPosition;
+ if (mMutator.ack()) {
+ bufferPosition = mCblk->u.mStatic.mBufferPosition;
+ if (bufferPosition > mFrameCount) {
+ bufferPosition = mFrameCount;
}
} else {
- return s - u;
+ bufferPosition = mBufferPosition;
}
+ return bufferPosition;
}
-bool audio_track_cblk_t::tryLock()
+// ---------------------------------------------------------------------------
+
+ServerProxy::ServerProxy(audio_track_cblk_t* cblk, void *buffers, size_t frameCount,
+ size_t frameSize, bool isOut, bool clientInServer)
+ : Proxy(cblk, buffers, frameCount, frameSize, isOut, clientInServer), mUnreleased(0),
+ mAvailToClient(0), mFlush(0), mDeferWake(false)
{
- // the code below simulates lock-with-timeout
- // we MUST do this to protect the AudioFlinger server
- // as this lock is shared with the client.
- status_t err;
-
- err = lock.tryLock();
- if (err == -EBUSY) { // just wait a bit
- usleep(1000);
- err = lock.tryLock();
- }
- if (err != NO_ERROR) {
- // probably, the client just died.
- return false;
- }
- return true;
}
+status_t ServerProxy::obtainBuffer(Buffer* buffer)
+{
+ if (mIsShutdown) {
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ mUnreleased = 0;
+ return NO_INIT;
+ }
+ audio_track_cblk_t* cblk = mCblk;
+ // compute number of frames available to write (AudioTrack) or read (AudioRecord),
+ // or use previous cached value from framesReady(), with added barrier if it omits.
+ int32_t front;
+ int32_t rear;
+ // See notes on barriers at ClientProxy::obtainBuffer()
+ if (mIsOut) {
+ int32_t flush = cblk->u.mStreaming.mFlush;
+ rear = android_atomic_acquire_load(&cblk->u.mStreaming.mRear);
+ if (flush != mFlush) {
+ front = rear;
+ mFlush = flush;
+ } else {
+ front = cblk->u.mStreaming.mFront;
+ }
+ } else {
+ front = android_atomic_acquire_load(&cblk->u.mStreaming.mFront);
+ rear = cblk->u.mStreaming.mRear;
+ }
+ ssize_t filled = rear - front;
+ // pipe should not already be overfull
+ if (!(0 <= filled && (size_t) filled <= mFrameCount)) {
+ ALOGE("Shared memory control block is corrupt (filled=%d); shutting down", filled);
+ mIsShutdown = true;
+ }
+ if (mIsShutdown) {
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ mUnreleased = 0;
+ return NO_INIT;
+ }
+ // don't allow filling pipe beyond the nominal size
+ size_t availToServer;
+ if (mIsOut) {
+ availToServer = filled;
+ mAvailToClient = mFrameCount - filled;
+ } else {
+ availToServer = mFrameCount - filled;
+ mAvailToClient = filled;
+ }
+ // 'availToServer' may be non-contiguous, so return only the first contiguous chunk
+ size_t part1;
+ if (mIsOut) {
+ front &= mFrameCountP2 - 1;
+ part1 = mFrameCountP2 - front;
+ } else {
+ rear &= mFrameCountP2 - 1;
+ part1 = mFrameCountP2 - rear;
+ }
+ if (part1 > availToServer) {
+ part1 = availToServer;
+ }
+ size_t ask = buffer->mFrameCount;
+ if (part1 > ask) {
+ part1 = ask;
+ }
+ // is assignment redundant in some cases?
+ buffer->mFrameCount = part1;
+ buffer->mRaw = part1 > 0 ?
+ &((char *) mBuffers)[(mIsOut ? front : rear) * mFrameSize] : NULL;
+ buffer->mNonContig = availToServer - part1;
+ mUnreleased = part1;
+ // optimization to avoid waking up the client too early
+ // FIXME need to test for recording
+ mDeferWake = part1 < ask && availToServer >= ask;
+ return part1 > 0 ? NO_ERROR : WOULD_BLOCK;
+}
+
+void ServerProxy::releaseBuffer(Buffer* buffer)
+{
+ if (mIsShutdown) {
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ return;
+ }
+ size_t stepCount = buffer->mFrameCount;
+ LOG_ALWAYS_FATAL_IF(stepCount > mUnreleased);
+ if (stepCount == 0) {
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ return;
+ }
+ mUnreleased -= stepCount;
+ audio_track_cblk_t* cblk = mCblk;
+ if (mIsOut) {
+ int32_t front = cblk->u.mStreaming.mFront;
+ android_atomic_release_store(stepCount + front, &cblk->u.mStreaming.mFront);
+ } else {
+ int32_t rear = cblk->u.mStreaming.mRear;
+ android_atomic_release_store(stepCount + rear, &cblk->u.mStreaming.mRear);
+ }
+
+ mCblk->server += stepCount;
+
+ size_t half = mFrameCount / 2;
+ if (half == 0) {
+ half = 1;
+ }
+ size_t minimum = cblk->mMinimum;
+ if (minimum == 0) {
+ minimum = mIsOut ? half : 1;
+ } else if (minimum > half) {
+ minimum = half;
+ }
+ if (!mDeferWake && mAvailToClient + stepCount >= minimum) {
+ ALOGV("mAvailToClient=%u stepCount=%u minimum=%u", mAvailToClient, stepCount, minimum);
+ // could client be sleeping, or not need this increment and counter overflows?
+ int32_t old = android_atomic_inc(&cblk->mFutex);
+ if (old == -1) {
+ (void) __futex_syscall3(&cblk->mFutex,
+ mClientInServer ? FUTEX_WAKE_PRIVATE : FUTEX_WAKE, 1);
+ }
+ }
+
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+}
+
+// ---------------------------------------------------------------------------
+
+size_t AudioTrackServerProxy::framesReady()
+{
+ LOG_ALWAYS_FATAL_IF(!mIsOut);
+
+ if (mIsShutdown) {
+ return 0;
+ }
+ audio_track_cblk_t* cblk = mCblk;
+ // the acquire might not be necessary since not doing a subsequent read
+ int32_t rear = android_atomic_acquire_load(&cblk->u.mStreaming.mRear);
+ ssize_t filled = rear - cblk->u.mStreaming.mFront;
+ // pipe should not already be overfull
+ if (!(0 <= filled && (size_t) filled <= mFrameCount)) {
+ ALOGE("Shared memory control block is corrupt (filled=%d); shutting down", filled);
+ mIsShutdown = true;
+ return 0;
+ }
+ // cache this value for later use by obtainBuffer(), with added barrier
+ // and racy if called by normal mixer thread
+ // ignores flush(), so framesReady() may report a larger mFrameCount than obtainBuffer()
+ return filled;
+}
+
+// ---------------------------------------------------------------------------
+
+StaticAudioTrackServerProxy::StaticAudioTrackServerProxy(audio_track_cblk_t* cblk, void *buffers,
+ size_t frameCount, size_t frameSize)
+ : AudioTrackServerProxy(cblk, buffers, frameCount, frameSize),
+ mObserver(&cblk->u.mStatic.mSingleStateQueue), mPosition(0),
+ mEnd(frameCount), mFramesReadyIsCalledByMultipleThreads(false)
+{
+ mState.mLoopStart = 0;
+ mState.mLoopEnd = 0;
+ mState.mLoopCount = 0;
+}
+
+void StaticAudioTrackServerProxy::framesReadyIsCalledByMultipleThreads()
+{
+ mFramesReadyIsCalledByMultipleThreads = true;
+}
+
+size_t StaticAudioTrackServerProxy::framesReady()
+{
+ // FIXME
+ // This is racy if called by normal mixer thread,
+ // as we're reading 2 independent variables without a lock.
+ // Can't call mObserver.poll(), as we might be called from wrong thread.
+ // If looping is enabled, should return a higher number (since includes non-contiguous).
+ size_t position = mPosition;
+ if (!mFramesReadyIsCalledByMultipleThreads) {
+ ssize_t positionOrStatus = pollPosition();
+ if (positionOrStatus >= 0) {
+ position = (size_t) positionOrStatus;
+ }
+ }
+ size_t end = mEnd;
+ return position < end ? end - position : 0;
+}
+
+ssize_t StaticAudioTrackServerProxy::pollPosition()
+{
+ size_t position = mPosition;
+ StaticAudioTrackState state;
+ if (mObserver.poll(state)) {
+ bool valid = false;
+ size_t loopStart = state.mLoopStart;
+ size_t loopEnd = state.mLoopEnd;
+ if (state.mLoopCount == 0) {
+ if (loopStart > mFrameCount) {
+ loopStart = mFrameCount;
+ }
+ // ignore loopEnd
+ mPosition = position = loopStart;
+ mEnd = mFrameCount;
+ mState.mLoopCount = 0;
+ valid = true;
+ } else {
+ if (loopStart < loopEnd && loopEnd <= mFrameCount &&
+ loopEnd - loopStart >= MIN_LOOP) {
+ if (!(loopStart <= position && position < loopEnd)) {
+ mPosition = position = loopStart;
+ }
+ mEnd = loopEnd;
+ mState = state;
+ valid = true;
+ }
+ }
+ if (!valid) {
+ ALOGE("%s client pushed an invalid state, shutting down", __func__);
+ mIsShutdown = true;
+ return (ssize_t) NO_INIT;
+ }
+ mCblk->u.mStatic.mBufferPosition = position;
+ }
+ return (ssize_t) position;
+}
+
+status_t StaticAudioTrackServerProxy::obtainBuffer(Buffer* buffer)
+{
+ if (mIsShutdown) {
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ mUnreleased = 0;
+ return NO_INIT;
+ }
+ ssize_t positionOrStatus = pollPosition();
+ if (positionOrStatus < 0) {
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ mUnreleased = 0;
+ return (status_t) positionOrStatus;
+ }
+ size_t position = (size_t) positionOrStatus;
+ size_t avail;
+ if (position < mEnd) {
+ avail = mEnd - position;
+ size_t wanted = buffer->mFrameCount;
+ if (avail < wanted) {
+ buffer->mFrameCount = avail;
+ } else {
+ avail = wanted;
+ }
+ buffer->mRaw = &((char *) mBuffers)[position * mFrameSize];
+ } else {
+ avail = 0;
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ }
+ buffer->mNonContig = 0; // FIXME should be > 0 for looping
+ mUnreleased = avail;
+ return NO_ERROR;
+}
+
+void StaticAudioTrackServerProxy::releaseBuffer(Buffer* buffer)
+{
+ size_t stepCount = buffer->mFrameCount;
+ LOG_ALWAYS_FATAL_IF(stepCount > mUnreleased);
+ if (stepCount == 0) {
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+ return;
+ }
+ mUnreleased -= stepCount;
+ audio_track_cblk_t* cblk = mCblk;
+ size_t position = mPosition;
+ size_t newPosition = position + stepCount;
+ int32_t setFlags = 0;
+ if (!(position <= newPosition && newPosition <= mFrameCount)) {
+ ALOGW("%s newPosition %u outside [%u, %u]", __func__, newPosition, position, mFrameCount);
+ newPosition = mFrameCount;
+ } else if (mState.mLoopCount != 0 && newPosition == mState.mLoopEnd) {
+ if (mState.mLoopCount == -1 || --mState.mLoopCount != 0) {
+ newPosition = mState.mLoopStart;
+ setFlags = CBLK_LOOP_CYCLE;
+ } else {
+ mEnd = mFrameCount; // this is what allows playback to continue after the loop
+ setFlags = CBLK_LOOP_FINAL;
+ }
+ }
+ if (newPosition == mFrameCount) {
+ setFlags |= CBLK_BUFFER_END;
+ }
+ mPosition = newPosition;
+
+ cblk->server += stepCount;
+ cblk->u.mStatic.mBufferPosition = newPosition;
+ if (setFlags != 0) {
+ (void) android_atomic_or(setFlags, &cblk->flags);
+ // this would be a good place to wake a futex
+ }
+
+ buffer->mFrameCount = 0;
+ buffer->mRaw = NULL;
+ buffer->mNonContig = 0;
+}
+
+// ---------------------------------------------------------------------------
+
} // namespace android