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t/samples/android-framework/android-5.1.1_r38/AudioTrackShared.cpp  view on Meta::CPAN

// ---------------------------------------------------------------------------

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)
{
}

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)
{
    LOG_ALWAYS_FATAL_IF(buffer == NULL || buffer->mFrameCount == 0);
    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

    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 {
        timeout = TIMEOUT_FINITE;
        if (requested->tv_sec > 0 || requested->tv_nsec >= MEASURE_NS) {
            measure = true;
        }
    }
    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->mFlags);
        // 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 {
            // 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)) {
            if (mIsOut) {
                ALOGE("Shared memory control block is corrupt (filled=%zd, mFrameCount=%zu); "
                        "shutting down", filled, mFrameCount);
                mIsShutdown = true;
                status = NO_INIT;
                goto end;
            }
            // for input, sync up on overrun
            filled = 0;
            cblk->u.mStreaming.mFront = rear;
            (void) android_atomic_or(CBLK_OVERRUN, &cblk->mFlags);
        }
        // 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;
            }
            if (part1 > avail) {
                part1 = avail;
            }
            if (part1 > buffer->mFrameCount) {
                part1 = buffer->mFrameCount;

t/samples/android-framework/android-5.1.1_r38/AudioTrackShared.cpp  view on Meta::CPAN

    } else {
        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=%zd); shutting down", filled);
        return 0;
    }
    return (size_t)filled;
}

// ---------------------------------------------------------------------------

void AudioTrackClientProxy::flush()
{
    // 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() {
    return (android_atomic_and(~CBLK_STREAM_END_DONE, &mCblk->mFlags) & CBLK_STREAM_END_DONE) != 0;
}

bool AudioTrackClientProxy::getStreamEndDone() const {
    return (mCblk->mFlags & CBLK_STREAM_END_DONE) != 0;
}

status_t AudioTrackClientProxy::waitStreamEndDone(const struct timespec *requested)
{
    struct timespec total;          // total elapsed time spent waiting
    total.tv_sec = 0;
    total.tv_nsec = 0;
    audio_track_cblk_t* cblk = mCblk;
    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 {
        timeout = TIMEOUT_FINITE;
    }
    for (;;) {
        int32_t flags = android_atomic_and(~(CBLK_INTERRUPT|CBLK_STREAM_END_DONE), &cblk->mFlags);
        // check for track invalidation by server, or server death detection
        if (flags & CBLK_INVALID) {
            ALOGV("Track invalidated");
            status = DEAD_OBJECT;
            goto end;
        }
        if (flags & CBLK_STREAM_END_DONE) {
            ALOGV("stream end received");
            status = NO_ERROR;
            goto end;
        }
        // check for obtainBuffer interrupted by client
        // check for obtainBuffer interrupted by client
        if (flags & CBLK_INTERRUPT) {
            ALOGV("waitStreamEndDone() interrupted by client");
            status = -EINTR;
            goto end;
        }
        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 (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_ALWAYS_FATAL("waitStreamEndDone() timeout=%d", timeout);
            ts = NULL;
            break;
        }
        int32_t old = android_atomic_and(~CBLK_FUTEX_WAKE, &cblk->mFutex);
        if (!(old & CBLK_FUTEX_WAKE)) {
            errno = 0;
            (void) syscall(__NR_futex, &cblk->mFutex,
                    mClientInServer ? FUTEX_WAIT_PRIVATE : FUTEX_WAIT, old & ~CBLK_FUTEX_WAKE, ts);
            switch (errno) {