services/audioflinger/Tracks.cpp

/*
**
** Copyright 2012, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**     http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/


#define LOG_TAG "AudioFlinger"
//#define LOG_NDEBUG 0

#include "Configuration.h"
#include <linux/futex.h>
#include <math.h>
#include <sys/syscall.h>
#include <utils/Log.h>

#include <private/media/AudioTrackShared.h>

#include "AudioFlinger.h"
#include "ServiceUtilities.h"

#include <media/nbaio/Pipe.h>
#include <media/nbaio/PipeReader.h>
#include <media/RecordBufferConverter.h>
#include <audio_utils/minifloat.h>

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

// Note: the following macro is used for extremely verbose logging message.  In
// order to run with ALOG_ASSERT turned on, we need to have LOG_NDEBUG set to
// 0; but one side effect of this is to turn all LOGV's as well.  Some messages
// are so verbose that we want to suppress them even when we have ALOG_ASSERT
// turned on.  Do not uncomment the #def below unless you really know what you
// are doing and want to see all of the extremely verbose messages.
//#define VERY_VERY_VERBOSE_LOGGING
#ifdef VERY_VERY_VERBOSE_LOGGING
#define ALOGVV ALOGV
#else
#define ALOGVV(a...) do { } while(0)
#endif

// TODO move to a common header  (Also shared with AudioTrack.cpp)
#define NANOS_PER_SECOND    1000000000
#define TIME_TO_NANOS(time) ((uint64_t)(time).tv_sec * NANOS_PER_SECOND + (time).tv_nsec)

namespace android {

// ----------------------------------------------------------------------------
//      TrackBase
// ----------------------------------------------------------------------------

static volatile int32_t nextTrackId = 55;

// TrackBase constructor must be called with AudioFlinger::mLock held
AudioFlinger::ThreadBase::TrackBase::TrackBase(
            ThreadBase *thread,
            const sp<Client>& client,
            uint32_t sampleRate,
            audio_format_t format,
            audio_channel_mask_t channelMask,
            size_t frameCount,
            void *buffer,
            audio_session_t sessionId,
            uid_t clientUid,
            bool isOut,
            alloc_type alloc,
            track_type type,
            audio_port_handle_t portId)
    :   RefBase(),
        mThread(thread),
        mClient(client),
        mCblk(NULL),
        // mBuffer
        mState(IDLE),
        mSampleRate(sampleRate),
        mFormat(format),
        mChannelMask(channelMask),
        mChannelCount(isOut ?
                audio_channel_count_from_out_mask(channelMask) :
                audio_channel_count_from_in_mask(channelMask)),
        mFrameSize(audio_has_proportional_frames(format) ?
                mChannelCount * audio_bytes_per_sample(format) : sizeof(int8_t)),
        mFrameCount(frameCount),
        mSessionId(sessionId),
        mIsOut(isOut),
        mId(android_atomic_inc(&nextTrackId)),
        mTerminated(false),
        mType(type),
        mThreadIoHandle(thread->id()),
        mPortId(portId),
        mIsInvalid(false)
{
    const uid_t callingUid = IPCThreadState::self()->getCallingUid();
    if (!isTrustedCallingUid(callingUid) || clientUid == AUDIO_UID_INVALID) {
        ALOGW_IF(clientUid != AUDIO_UID_INVALID && clientUid != callingUid,
                "%s uid %d tried to pass itself off as %d", __FUNCTION__, callingUid, clientUid);
        clientUid = callingUid;
    }
    // clientUid contains the uid of the app that is responsible for this track, so we can blame
    // battery usage on it.
    mUid = clientUid;

    // ALOGD("Creating track with %d buffers @ %d bytes", bufferCount, bufferSize);

    size_t bufferSize = buffer == NULL ? roundup(frameCount) : frameCount;
    // check overflow when computing bufferSize due to multiplication by mFrameSize.
    if (bufferSize < frameCount  // roundup rounds down for values above UINT_MAX / 2
            || mFrameSize == 0   // format needs to be correct
            || bufferSize > SIZE_MAX / mFrameSize) {
        android_errorWriteLog(0x534e4554, "34749571");
        return;
    }
    bufferSize *= mFrameSize;

    size_t size = sizeof(audio_track_cblk_t);
    if (buffer == NULL && alloc == ALLOC_CBLK) {
        // check overflow when computing allocation size for streaming tracks.
        if (size > SIZE_MAX - bufferSize) {
            android_errorWriteLog(0x534e4554, "34749571");
            return;
        }
        size += bufferSize;
    }

    if (client != 0) {
        mCblkMemory = client->heap()->allocate(size);
        if (mCblkMemory == 0 ||
                (mCblk = static_cast<audio_track_cblk_t *>(mCblkMemory->pointer())) == NULL) {
            ALOGE("not enough memory for AudioTrack size=%zu", size);
            client->heap()->dump("AudioTrack");
            mCblkMemory.clear();
            return;
        }
    } else {
        mCblk = (audio_track_cblk_t *) malloc(size);
        if (mCblk == NULL) {
            ALOGE("not enough memory for AudioTrack size=%zu", size);
            return;
        }
    }

    // construct the shared structure in-place.
    if (mCblk != NULL) {
        new(mCblk) audio_track_cblk_t();
        switch (alloc) {
        case ALLOC_READONLY: {
            const sp<MemoryDealer> roHeap(thread->readOnlyHeap());
            if (roHeap == 0 ||
                    (mBufferMemory = roHeap->allocate(bufferSize)) == 0 ||
                    (mBuffer = mBufferMemory->pointer()) == NULL) {
                ALOGE("not enough memory for read-only buffer size=%zu", bufferSize);
                if (roHeap != 0) {
                    roHeap->dump("buffer");
                }
                mCblkMemory.clear();
                mBufferMemory.clear();
                return;
            }
            memset(mBuffer, 0, bufferSize);
            } break;
        case ALLOC_PIPE:
            mBufferMemory = thread->pipeMemory();
            // mBuffer is the virtual address as seen from current process (mediaserver),
            // and should normally be coming from mBufferMemory->pointer().
            // However in this case the TrackBase does not reference the buffer directly.
            // It should references the buffer via the pipe.
            // Therefore, to detect incorrect usage of the buffer, we set mBuffer to NULL.
            mBuffer = NULL;
            break;
        case ALLOC_CBLK:
            // clear all buffers
            if (buffer == NULL) {
                mBuffer = (char*)mCblk + sizeof(audio_track_cblk_t);
                memset(mBuffer, 0, bufferSize);
            } else {
                mBuffer = buffer;
#if 0
                mCblk->mFlags = CBLK_FORCEREADY;    // FIXME hack, need to fix the track ready logic
#endif
            }
            break;
        case ALLOC_LOCAL:
            mBuffer = calloc(1, bufferSize);
            break;
        case ALLOC_NONE:
            mBuffer = buffer;
            break;
        }

#ifdef TEE_SINK
        if (mTeeSinkTrackEnabled) {
            NBAIO_Format pipeFormat = Format_from_SR_C(mSampleRate, mChannelCount, mFormat);
            if (Format_isValid(pipeFormat)) {
                Pipe *pipe = new Pipe(mTeeSinkTrackFrames, pipeFormat);
                size_t numCounterOffers = 0;
                const NBAIO_Format offers[1] = {pipeFormat};
                ssize_t index = pipe->negotiate(offers, 1, NULL, numCounterOffers);
                ALOG_ASSERT(index == 0);
                PipeReader *pipeReader = new PipeReader(*pipe);
                numCounterOffers = 0;
                index = pipeReader->negotiate(offers, 1, NULL, numCounterOffers);
                ALOG_ASSERT(index == 0);
                mTeeSink = pipe;
                mTeeSource = pipeReader;
            }
        }
#endif

    }
}

status_t AudioFlinger::ThreadBase::TrackBase::initCheck() const
{
    status_t status;
    if (mType == TYPE_OUTPUT || mType == TYPE_PATCH) {
        status = cblk() != NULL ? NO_ERROR : NO_MEMORY;
    } else {
        status = getCblk() != 0 ? NO_ERROR : NO_MEMORY;
    }
    return status;
}

AudioFlinger::ThreadBase::TrackBase::~TrackBase()
{
#ifdef TEE_SINK
    dumpTee(-1, mTeeSource, mId, 'T');
#endif
    // delete the proxy before deleting the shared memory it refers to, to avoid dangling reference
    mServerProxy.clear();
    if (mCblk != NULL) {
        mCblk->~audio_track_cblk_t();   // destroy our shared-structure.
        if (mClient == 0) {
            free(mCblk);
        }
    }
    mCblkMemory.clear();    // free the shared memory before releasing the heap it belongs to
    if (mClient != 0) {
        // Client destructor must run with AudioFlinger client mutex locked
        Mutex::Autolock _l(mClient->audioFlinger()->mClientLock);
        // If the client's reference count drops to zero, the associated destructor
        // must run with AudioFlinger lock held. Thus the explicit clear() rather than
        // relying on the automatic clear() at end of scope.
        mClient.clear();
    }
    // flush the binder command buffer
    IPCThreadState::self()->flushCommands();
}

// AudioBufferProvider interface
// getNextBuffer() = 0;
// This implementation of releaseBuffer() is used by Track and RecordTrack
void AudioFlinger::ThreadBase::TrackBase::releaseBuffer(AudioBufferProvider::Buffer* buffer)
{
#ifdef TEE_SINK
    if (mTeeSink != 0) {
        (void) mTeeSink->write(buffer->raw, buffer->frameCount);
    }
#endif

    ServerProxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    buf.mRaw = buffer->raw;
    buffer->frameCount = 0;
    buffer->raw = NULL;
    mServerProxy->releaseBuffer(&buf);
}

status_t AudioFlinger::ThreadBase::TrackBase::setSyncEvent(const sp<SyncEvent>& event)
{
    mSyncEvents.add(event);
    return NO_ERROR;
}

// ----------------------------------------------------------------------------
//      Playback
// ----------------------------------------------------------------------------

AudioFlinger::TrackHandle::TrackHandle(const sp<AudioFlinger::PlaybackThread::Track>& track)
    : BnAudioTrack(),
      mTrack(track)
{
}

AudioFlinger::TrackHandle::~TrackHandle() {
    // just stop the track on deletion, associated resources
    // will be freed from the main thread once all pending buffers have
    // been played. Unless it's not in the active track list, in which
    // case we free everything now...
    mTrack->destroy();
}

sp<IMemory> AudioFlinger::TrackHandle::getCblk() const {
    return mTrack->getCblk();
}

status_t AudioFlinger::TrackHandle::start() {
    return mTrack->start();
}

void AudioFlinger::TrackHandle::stop() {
    mTrack->stop();
}

void AudioFlinger::TrackHandle::flush() {
    mTrack->flush();
}

void AudioFlinger::TrackHandle::pause() {
    mTrack->pause();
}

status_t AudioFlinger::TrackHandle::attachAuxEffect(int EffectId)
{
    return mTrack->attachAuxEffect(EffectId);
}

status_t AudioFlinger::TrackHandle::setParameters(const String8& keyValuePairs) {
    return mTrack->setParameters(keyValuePairs);
}

VolumeShaper::Status AudioFlinger::TrackHandle::applyVolumeShaper(
        const sp<VolumeShaper::Configuration>& configuration,
        const sp<VolumeShaper::Operation>& operation) {
    return mTrack->applyVolumeShaper(configuration, operation);
}

sp<VolumeShaper::State> AudioFlinger::TrackHandle::getVolumeShaperState(int id) {
    return mTrack->getVolumeShaperState(id);
}

status_t AudioFlinger::TrackHandle::getTimestamp(AudioTimestamp& timestamp)
{
    return mTrack->getTimestamp(timestamp);
}


void AudioFlinger::TrackHandle::signal()
{
    return mTrack->signal();
}

status_t AudioFlinger::TrackHandle::onTransact(
    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
{
    return BnAudioTrack::onTransact(code, data, reply, flags);
}

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

// Track constructor must be called with AudioFlinger::mLock and ThreadBase::mLock held
AudioFlinger::PlaybackThread::Track::Track(
            PlaybackThread *thread,
            const sp<Client>& client,
            audio_stream_type_t streamType,
            uint32_t sampleRate,
            audio_format_t format,
            audio_channel_mask_t channelMask,
            size_t frameCount,
            void *buffer,
            const sp<IMemory>& sharedBuffer,
            audio_session_t sessionId,
            uid_t uid,
            audio_output_flags_t flags,
            track_type type,
            audio_port_handle_t portId)
    :   TrackBase(thread, client, sampleRate, format, channelMask, frameCount,
                  (sharedBuffer != 0) ? sharedBuffer->pointer() : buffer,
                  sessionId, uid, true /*isOut*/,
                  (type == TYPE_PATCH) ? ( buffer == NULL ? ALLOC_LOCAL : ALLOC_NONE) : ALLOC_CBLK,
                  type, portId),
    mFillingUpStatus(FS_INVALID),
    // mRetryCount initialized later when needed
    mSharedBuffer(sharedBuffer),
    mStreamType(streamType),
    mName(-1),  // see note below
    mMainBuffer(thread->mixBuffer()),
    mAuxBuffer(NULL),
    mAuxEffectId(0), mHasVolumeController(false),
    mPresentationCompleteFrames(0),
    mFrameMap(16 /* sink-frame-to-track-frame map memory */),
    mVolumeHandler(new VolumeHandler(sampleRate)),
    // mSinkTimestamp
    mFastIndex(-1),
    mCachedVolume(1.0),
    mResumeToStopping(false),
    mFlushHwPending(false),
    mFlags(flags)
{
    // client == 0 implies sharedBuffer == 0
    ALOG_ASSERT(!(client == 0 && sharedBuffer != 0));

    ALOGV_IF(sharedBuffer != 0, "sharedBuffer: %p, size: %zu", sharedBuffer->pointer(),
            sharedBuffer->size());

    if (mCblk == NULL) {
        return;
    }

    if (sharedBuffer == 0) {
        mAudioTrackServerProxy = new AudioTrackServerProxy(mCblk, mBuffer, frameCount,
                mFrameSize, !isExternalTrack(), sampleRate);
    } else {
        mAudioTrackServerProxy = new StaticAudioTrackServerProxy(mCblk, mBuffer, frameCount,
                mFrameSize);
    }
    mServerProxy = mAudioTrackServerProxy;

    mName = thread->getTrackName_l(channelMask, format, sessionId, uid);
    if (mName < 0) {
        ALOGE("no more track names available");
        return;
    }
    // only allocate a fast track index if we were able to allocate a normal track name
    if (flags & AUDIO_OUTPUT_FLAG_FAST) {
        // FIXME: Not calling framesReadyIsCalledByMultipleThreads() exposes a potential
        // race with setSyncEvent(). However, if we call it, we cannot properly start
        // static fast tracks (SoundPool) immediately after stopping.
        //mAudioTrackServerProxy->framesReadyIsCalledByMultipleThreads();
        ALOG_ASSERT(thread->mFastTrackAvailMask != 0);
        int i = __builtin_ctz(thread->mFastTrackAvailMask);
        ALOG_ASSERT(0 < i && i < (int)FastMixerState::sMaxFastTracks);
        // FIXME This is too eager.  We allocate a fast track index before the
        //       fast track becomes active.  Since fast tracks are a scarce resource,
        //       this means we are potentially denying other more important fast tracks from
        //       being created.  It would be better to allocate the index dynamically.
        mFastIndex = i;
        thread->mFastTrackAvailMask &= ~(1 << i);
    }
}

AudioFlinger::PlaybackThread::Track::~Track()
{
    ALOGV("PlaybackThread::Track destructor");

    // The destructor would clear mSharedBuffer,
    // but it will not push the decremented reference count,
    // leaving the client's IMemory dangling indefinitely.
    // This prevents that leak.
    if (mSharedBuffer != 0) {
        mSharedBuffer.clear();
    }
}

status_t AudioFlinger::PlaybackThread::Track::initCheck() const
{
    status_t status = TrackBase::initCheck();
    if (status == NO_ERROR && mName < 0) {
        status = NO_MEMORY;
    }
    return status;
}

void AudioFlinger::PlaybackThread::Track::destroy()
{
    // NOTE: destroyTrack_l() can remove a strong reference to this Track
    // by removing it from mTracks vector, so there is a risk that this Tracks's
    // destructor is called. As the destructor needs to lock mLock,
    // we must acquire a strong reference on this Track before locking mLock
    // here so that the destructor is called only when exiting this function.
    // On the other hand, as long as Track::destroy() is only called by
    // TrackHandle destructor, the TrackHandle still holds a strong ref on
    // this Track with its member mTrack.
    sp<Track> keep(this);
    { // scope for mLock
        bool wasActive = false;
        sp<ThreadBase> thread = mThread.promote();
        if (thread != 0) {
            Mutex::Autolock _l(thread->mLock);
            PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
            wasActive = playbackThread->destroyTrack_l(this);
        }
        if (isExternalTrack() && !wasActive) {
            AudioSystem::releaseOutput(mThreadIoHandle, mStreamType, mSessionId);
        }
    }
}

/*static*/ void AudioFlinger::PlaybackThread::Track::appendDumpHeader(String8& result)
{
    result.append("    Name Active Client Type      Fmt Chn mask Session fCount S F SRate  "
                  "L dB  R dB  VS dB    Server Main buf  Aux buf Flags UndFrmCnt  Flushed\n");
}

void AudioFlinger::PlaybackThread::Track::dump(char* buffer, size_t size, bool active)
{
    gain_minifloat_packed_t vlr = mAudioTrackServerProxy->getVolumeLR();
    if (isFastTrack()) {
        sprintf(buffer, "    F %2d", mFastIndex);
    } else if (mName >= AudioMixer::TRACK0) {
        sprintf(buffer, "    %4d", mName - AudioMixer::TRACK0);
    } else {
        sprintf(buffer, "    none");
    }
    track_state state = mState;
    char stateChar;
    if (isTerminated()) {
        stateChar = 'T';
    } else {
        switch (state) {
        case IDLE:
            stateChar = 'I';
            break;
        case STOPPING_1:
            stateChar = 's';
            break;
        case STOPPING_2:
            stateChar = '5';
            break;
        case STOPPED:
            stateChar = 'S';
            break;
        case RESUMING:
            stateChar = 'R';
            break;
        case ACTIVE:
            stateChar = 'A';
            break;
        case PAUSING:
            stateChar = 'p';
            break;
        case PAUSED:
            stateChar = 'P';
            break;
        case FLUSHED:
            stateChar = 'F';
            break;
        default:
            stateChar = '?';
            break;
        }
    }
    char nowInUnderrun;
    switch (mObservedUnderruns.mBitFields.mMostRecent) {
    case UNDERRUN_FULL:
        nowInUnderrun = ' ';
        break;
    case UNDERRUN_PARTIAL:
        nowInUnderrun = '<';
        break;
    case UNDERRUN_EMPTY:
        nowInUnderrun = '*';
        break;
    default:
        nowInUnderrun = '?';
        break;
    }

    std::pair<float /* volume */, bool /* active */> vsVolume = mVolumeHandler->getLastVolume();
    snprintf(&buffer[8], size - 8, " %6s %6u %4u %08X %08X %7u %6zu %1c %1d %5u "
                                   "%5.2g %5.2g %5.2g%c  "
                                   "%08X %08zX %08zX 0x%03X %9u%c %7u\n",
            active ? "yes" : "no",
            (mClient == 0) ? getpid_cached : mClient->pid(),
            mStreamType,
            mFormat,
            mChannelMask,
            mSessionId,
            mFrameCount,
            stateChar,
            mFillingUpStatus,
            mAudioTrackServerProxy->getSampleRate(),
            20.0 * log10(float_from_gain(gain_minifloat_unpack_left(vlr))),
            20.0 * log10(float_from_gain(gain_minifloat_unpack_right(vlr))),
            20.0 * log10(vsVolume.first), // VolumeShaper(s) total volume
            vsVolume.second ? 'A' : ' ',  // if any VolumeShapers active
            mCblk->mServer,
            (size_t)mMainBuffer, // use %zX as %p appends 0x
            (size_t)mAuxBuffer,  // use %zX as %p appends 0x
            mCblk->mFlags,
            mAudioTrackServerProxy->getUnderrunFrames(),
            nowInUnderrun,
            (unsigned)mAudioTrackServerProxy->framesFlushed() % 10000000); // 7 digits
}

uint32_t AudioFlinger::PlaybackThread::Track::sampleRate() const {
    return mAudioTrackServerProxy->getSampleRate();
}

// AudioBufferProvider interface
status_t AudioFlinger::PlaybackThread::Track::getNextBuffer(
        AudioBufferProvider::Buffer* buffer)
{
    ServerProxy::Buffer buf;
    size_t desiredFrames = buffer->frameCount;
    buf.mFrameCount = desiredFrames;
    status_t status = mServerProxy->obtainBuffer(&buf);
    buffer->frameCount = buf.mFrameCount;
    buffer->raw = buf.mRaw;
    if (buf.mFrameCount == 0 && !isStopping() && !isStopped() && !isPaused()) {
        ALOGV("underrun,  framesReady(%zu) < framesDesired(%zd), state: %d",
                buf.mFrameCount, desiredFrames, mState);
        mAudioTrackServerProxy->tallyUnderrunFrames(desiredFrames);
    } else {
        mAudioTrackServerProxy->tallyUnderrunFrames(0);
    }

    return status;
}

// releaseBuffer() is not overridden

// ExtendedAudioBufferProvider interface

// framesReady() may return an approximation of the number of frames if called
// from a different thread than the one calling Proxy->obtainBuffer() and
// Proxy->releaseBuffer(). Also note there is no mutual exclusion in the
// AudioTrackServerProxy so be especially careful calling with FastTracks.
size_t AudioFlinger::PlaybackThread::Track::framesReady() const {
    if (mSharedBuffer != 0 && (isStopped() || isStopping())) {
        // Static tracks return zero frames immediately upon stopping (for FastTracks).
        // The remainder of the buffer is not drained.
        return 0;
    }
    return mAudioTrackServerProxy->framesReady();
}

int64_t AudioFlinger::PlaybackThread::Track::framesReleased() const
{
    return mAudioTrackServerProxy->framesReleased();
}

void AudioFlinger::PlaybackThread::Track::onTimestamp(const ExtendedTimestamp &timestamp)
{
    // This call comes from a FastTrack and should be kept lockless.
    // The server side frames are already translated to client frames.
    mAudioTrackServerProxy->setTimestamp(timestamp);

    // We do not set drained here, as FastTrack timestamp may not go to very last frame.
}

// Don't call for fast tracks; the framesReady() could result in priority inversion
bool AudioFlinger::PlaybackThread::Track::isReady() const {
    if (mFillingUpStatus != FS_FILLING || isStopped() || isPausing()) {
        return true;
    }

    if (isStopping()) {
        if (framesReady() > 0) {
            mFillingUpStatus = FS_FILLED;
        }
        return true;
    }

    if (framesReady() >= mServerProxy->getBufferSizeInFrames() ||
            (mCblk->mFlags & CBLK_FORCEREADY)) {
        mFillingUpStatus = FS_FILLED;
        android_atomic_and(~CBLK_FORCEREADY, &mCblk->mFlags);
        return true;
    }
    return false;
}

status_t AudioFlinger::PlaybackThread::Track::start(AudioSystem::sync_event_t event __unused,
                                                    audio_session_t triggerSession __unused)
{
    status_t status = NO_ERROR;
    ALOGV("start(%d), calling pid %d session %d",
            mName, IPCThreadState::self()->getCallingPid(), mSessionId);

    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        if (isOffloaded()) {
            Mutex::Autolock _laf(thread->mAudioFlinger->mLock);
            Mutex::Autolock _lth(thread->mLock);
            sp<EffectChain> ec = thread->getEffectChain_l(mSessionId);
            if (thread->mAudioFlinger->isNonOffloadableGlobalEffectEnabled_l() ||
                    (ec != 0 && ec->isNonOffloadableEnabled())) {
                invalidate();
                return PERMISSION_DENIED;
            }
        }
        Mutex::Autolock _lth(thread->mLock);
        track_state state = mState;
        // here the track could be either new, or restarted
        // in both cases "unstop" the track

        // initial state-stopping. next state-pausing.
        // What if resume is called ?

        if (state == PAUSED || state == PAUSING) {
            if (mResumeToStopping) {
                // happened we need to resume to STOPPING_1
                mState = TrackBase::STOPPING_1;
                ALOGV("PAUSED => STOPPING_1 (%d) on thread %p", mName, this);
            } else {
                mState = TrackBase::RESUMING;
                ALOGV("PAUSED => RESUMING (%d) on thread %p", mName, this);
            }
        } else {
            mState = TrackBase::ACTIVE;
            ALOGV("? => ACTIVE (%d) on thread %p", mName, this);
        }

        // states to reset position info for non-offloaded/direct tracks
        if (!isOffloaded() && !isDirect()
                && (state == IDLE || state == STOPPED || state == FLUSHED)) {
            mFrameMap.reset();
        }
        PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
        if (isFastTrack()) {
            // refresh fast track underruns on start because that field is never cleared
            // by the fast mixer; furthermore, the same track can be recycled, i.e. start
            // after stop.
            mObservedUnderruns = playbackThread->getFastTrackUnderruns(mFastIndex);
        }
        status = playbackThread->addTrack_l(this);
        if (status == INVALID_OPERATION || status == PERMISSION_DENIED) {
            triggerEvents(AudioSystem::SYNC_EVENT_PRESENTATION_COMPLETE);
            //  restore previous state if start was rejected by policy manager
            if (status == PERMISSION_DENIED) {
                mState = state;
            }
        }
        // track was already in the active list, not a problem
        if (status == ALREADY_EXISTS) {
            status = NO_ERROR;
        } else {
            // Acknowledge any pending flush(), so that subsequent new data isn't discarded.
            // It is usually unsafe to access the server proxy from a binder thread.
            // But in this case we know the mixer thread (whether normal mixer or fast mixer)
            // isn't looking at this track yet:  we still hold the normal mixer thread lock,
            // and for fast tracks the track is not yet in the fast mixer thread's active set.
            // For static tracks, this is used to acknowledge change in position or loop.
            ServerProxy::Buffer buffer;
            buffer.mFrameCount = 1;
            (void) mAudioTrackServerProxy->obtainBuffer(&buffer, true /*ackFlush*/);
        }
    } else {
        status = BAD_VALUE;
    }
    return status;
}

void AudioFlinger::PlaybackThread::Track::stop()
{
    ALOGV("stop(%d), calling pid %d", mName, IPCThreadState::self()->getCallingPid());
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        Mutex::Autolock _l(thread->mLock);
        track_state state = mState;
        if (state == RESUMING || state == ACTIVE || state == PAUSING || state == PAUSED) {
            // If the track is not active (PAUSED and buffers full), flush buffers
            PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
            if (playbackThread->mActiveTracks.indexOf(this) < 0) {
                reset();
                mState = STOPPED;
            } else if (!isFastTrack() && !isOffloaded() && !isDirect()) {
                mState = STOPPED;
            } else {
                // For fast tracks prepareTracks_l() will set state to STOPPING_2
                // presentation is complete
                // For an offloaded track this starts a drain and state will
                // move to STOPPING_2 when drain completes and then STOPPED
                mState = STOPPING_1;
                if (isOffloaded()) {
                    mRetryCount = PlaybackThread::kMaxTrackStopRetriesOffload;
                }
            }
            playbackThread->broadcast_l();
            ALOGV("not stopping/stopped => stopping/stopped (%d) on thread %p", mName,
                    playbackThread);
        }
    }
}

void AudioFlinger::PlaybackThread::Track::pause()
{
    ALOGV("pause(%d), calling pid %d", mName, IPCThreadState::self()->getCallingPid());
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        Mutex::Autolock _l(thread->mLock);
        PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
        switch (mState) {
        case STOPPING_1:
        case STOPPING_2:
            if (!isOffloaded()) {
                /* nothing to do if track is not offloaded */
                break;
            }

            // Offloaded track was draining, we need to carry on draining when resumed
            mResumeToStopping = true;
            // fall through...
        case ACTIVE:
        case RESUMING:
            mState = PAUSING;
            ALOGV("ACTIVE/RESUMING => PAUSING (%d) on thread %p", mName, thread.get());
            playbackThread->broadcast_l();
            break;

        default:
            break;
        }
    }
}

void AudioFlinger::PlaybackThread::Track::flush()
{
    ALOGV("flush(%d)", mName);
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        Mutex::Autolock _l(thread->mLock);
        PlaybackThread *playbackThread = (PlaybackThread *)thread.get();

        // Flush the ring buffer now if the track is not active in the PlaybackThread.
        // Otherwise the flush would not be done until the track is resumed.
        // Requires FastTrack removal be BLOCK_UNTIL_ACKED
        if (playbackThread->mActiveTracks.indexOf(this) < 0) {
            (void)mServerProxy->flushBufferIfNeeded();
        }

        if (isOffloaded()) {
            // If offloaded we allow flush during any state except terminated
            // and keep the track active to avoid problems if user is seeking
            // rapidly and underlying hardware has a significant delay handling
            // a pause
            if (isTerminated()) {
                return;
            }

            ALOGV("flush: offload flush");
            reset();

            if (mState == STOPPING_1 || mState == STOPPING_2) {
                ALOGV("flushed in STOPPING_1 or 2 state, change state to ACTIVE");
                mState = ACTIVE;
            }

            mFlushHwPending = true;
            mResumeToStopping = false;
        } else {
            if (mState != STOPPING_1 && mState != STOPPING_2 && mState != STOPPED &&
                    mState != PAUSED && mState != PAUSING && mState != IDLE && mState != FLUSHED) {
                return;
            }
            // No point remaining in PAUSED state after a flush => go to
            // FLUSHED state
            mState = FLUSHED;
            // do not reset the track if it is still in the process of being stopped or paused.
            // this will be done by prepareTracks_l() when the track is stopped.
            // prepareTracks_l() will see mState == FLUSHED, then
            // remove from active track list, reset(), and trigger presentation complete
            if (isDirect()) {
                mFlushHwPending = true;
            }
            if (playbackThread->mActiveTracks.indexOf(this) < 0) {
                reset();
            }
        }
        // Prevent flush being lost if the track is flushed and then resumed
        // before mixer thread can run. This is important when offloading
        // because the hardware buffer could hold a large amount of audio
        playbackThread->broadcast_l();
    }
}

// must be called with thread lock held
void AudioFlinger::PlaybackThread::Track::flushAck()
{
    if (!isOffloaded() && !isDirect())
        return;

    // Clear the client ring buffer so that the app can prime the buffer while paused.
    // Otherwise it might not get cleared until playback is resumed and obtainBuffer() is called.
    mServerProxy->flushBufferIfNeeded();

    mFlushHwPending = false;
}

void AudioFlinger::PlaybackThread::Track::reset()
{
    // Do not reset twice to avoid discarding data written just after a flush and before
    // the audioflinger thread detects the track is stopped.
    if (!mResetDone) {
        // Force underrun condition to avoid false underrun callback until first data is
        // written to buffer
        android_atomic_and(~CBLK_FORCEREADY, &mCblk->mFlags);
        mFillingUpStatus = FS_FILLING;
        mResetDone = true;
        if (mState == FLUSHED) {
            mState = IDLE;
        }
    }
}

status_t AudioFlinger::PlaybackThread::Track::setParameters(const String8& keyValuePairs)
{
    sp<ThreadBase> thread = mThread.promote();
    if (thread == 0) {
        ALOGE("thread is dead");
        return FAILED_TRANSACTION;
    } else if ((thread->type() == ThreadBase::DIRECT) ||
                    (thread->type() == ThreadBase::OFFLOAD)) {
        return thread->setParameters(keyValuePairs);
    } else {
        return PERMISSION_DENIED;
    }
}

VolumeShaper::Status AudioFlinger::PlaybackThread::Track::applyVolumeShaper(
        const sp<VolumeShaper::Configuration>& configuration,
        const sp<VolumeShaper::Operation>& operation)
{
    sp<VolumeShaper::Configuration> newConfiguration;

    if (isOffloadedOrDirect()) {
        const VolumeShaper::Configuration::OptionFlag optionFlag
            = configuration->getOptionFlags();
        if ((optionFlag & VolumeShaper::Configuration::OPTION_FLAG_CLOCK_TIME) == 0) {
            ALOGW("%s tracks do not support frame counted VolumeShaper,"
                    " using clock time instead", isOffloaded() ? "Offload" : "Direct");
            newConfiguration = new VolumeShaper::Configuration(*configuration);
            newConfiguration->setOptionFlags(
                VolumeShaper::Configuration::OptionFlag(optionFlag
                        | VolumeShaper::Configuration::OPTION_FLAG_CLOCK_TIME));
        }
    }

    VolumeShaper::Status status = mVolumeHandler->applyVolumeShaper(
            (newConfiguration.get() != nullptr ? newConfiguration : configuration), operation);

    if (isOffloadedOrDirect()) {
        // Signal thread to fetch new volume.
        sp<ThreadBase> thread = mThread.promote();
        if (thread != 0) {
             Mutex::Autolock _l(thread->mLock);
            thread->broadcast_l();
        }
    }
    return status;
}

sp<VolumeShaper::State> AudioFlinger::PlaybackThread::Track::getVolumeShaperState(int id)
{
    // Note: We don't check if Thread exists.

    // mVolumeHandler is thread safe.
    return mVolumeHandler->getVolumeShaperState(id);
}

status_t AudioFlinger::PlaybackThread::Track::getTimestamp(AudioTimestamp& timestamp)
{
    if (!isOffloaded() && !isDirect()) {
        return INVALID_OPERATION; // normal tracks handled through SSQ
    }
    sp<ThreadBase> thread = mThread.promote();
    if (thread == 0) {
        return INVALID_OPERATION;
    }

    Mutex::Autolock _l(thread->mLock);
    PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
    return playbackThread->getTimestamp_l(timestamp);
}

status_t AudioFlinger::PlaybackThread::Track::attachAuxEffect(int EffectId)
{
    status_t status = DEAD_OBJECT;
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        PlaybackThread *playbackThread = (PlaybackThread *)thread.get();
        sp<AudioFlinger> af = mClient->audioFlinger();

        Mutex::Autolock _l(af->mLock);

        sp<PlaybackThread> srcThread = af->getEffectThread_l(AUDIO_SESSION_OUTPUT_MIX, EffectId);

        if (EffectId != 0 && srcThread != 0 && playbackThread != srcThread.get()) {
            Mutex::Autolock _dl(playbackThread->mLock);
            Mutex::Autolock _sl(srcThread->mLock);
            sp<EffectChain> chain = srcThread->getEffectChain_l(AUDIO_SESSION_OUTPUT_MIX);
            if (chain == 0) {
                return INVALID_OPERATION;
            }

            sp<EffectModule> effect = chain->getEffectFromId_l(EffectId);
            if (effect == 0) {
                return INVALID_OPERATION;
            }
            srcThread->removeEffect_l(effect);
            status = playbackThread->addEffect_l(effect);
            if (status != NO_ERROR) {
                srcThread->addEffect_l(effect);
                return INVALID_OPERATION;
            }
            // removeEffect_l() has stopped the effect if it was active so it must be restarted
            if (effect->state() == EffectModule::ACTIVE ||
                    effect->state() == EffectModule::STOPPING) {
                effect->start();
            }

            sp<EffectChain> dstChain = effect->chain().promote();
            if (dstChain == 0) {
                srcThread->addEffect_l(effect);
                return INVALID_OPERATION;
            }
            AudioSystem::unregisterEffect(effect->id());
            AudioSystem::registerEffect(&effect->desc(),
                                        srcThread->id(),
                                        dstChain->strategy(),
                                        AUDIO_SESSION_OUTPUT_MIX,
                                        effect->id());
            AudioSystem::setEffectEnabled(effect->id(), effect->isEnabled());
        }
        status = playbackThread->attachAuxEffect(this, EffectId);
    }
    return status;
}

void AudioFlinger::PlaybackThread::Track::setAuxBuffer(int EffectId, int32_t *buffer)
{
    mAuxEffectId = EffectId;
    mAuxBuffer = buffer;
}

bool AudioFlinger::PlaybackThread::Track::presentationComplete(
        int64_t framesWritten, size_t audioHalFrames)
{
    // TODO: improve this based on FrameMap if it exists, to ensure full drain.
    // This assists in proper timestamp computation as well as wakelock management.

    // a track is considered presented when the total number of frames written to audio HAL
    // corresponds to the number of frames written when presentationComplete() is called for the
    // first time (mPresentationCompleteFrames == 0) plus the buffer filling status at that time.
    // For an offloaded track the HAL+h/w delay is variable so a HAL drain() is used
    // to detect when all frames have been played. In this case framesWritten isn't
    // useful because it doesn't always reflect whether there is data in the h/w
    // buffers, particularly if a track has been paused and resumed during draining
    ALOGV("presentationComplete() mPresentationCompleteFrames %lld framesWritten %lld",
            (long long)mPresentationCompleteFrames, (long long)framesWritten);
    if (mPresentationCompleteFrames == 0) {
        mPresentationCompleteFrames = framesWritten + audioHalFrames;
        ALOGV("presentationComplete() reset: mPresentationCompleteFrames %lld audioHalFrames %zu",
                (long long)mPresentationCompleteFrames, audioHalFrames);
    }

    bool complete;
    if (isOffloaded()) {
        complete = true;
    } else if (isDirect() || isFastTrack()) { // these do not go through linear map
        complete = framesWritten >= (int64_t) mPresentationCompleteFrames;
    } else {  // Normal tracks, OutputTracks, and PatchTracks
        complete = framesWritten >= (int64_t) mPresentationCompleteFrames
                && mAudioTrackServerProxy->isDrained();
    }

    if (complete) {
        triggerEvents(AudioSystem::SYNC_EVENT_PRESENTATION_COMPLETE);
        mAudioTrackServerProxy->setStreamEndDone();
        return true;
    }
    return false;
}

void AudioFlinger::PlaybackThread::Track::triggerEvents(AudioSystem::sync_event_t type)
{
    for (size_t i = 0; i < mSyncEvents.size(); i++) {
        if (mSyncEvents[i]->type() == type) {
            mSyncEvents[i]->trigger();
            mSyncEvents.removeAt(i);
            i--;
        }
    }
}

// implement VolumeBufferProvider interface

gain_minifloat_packed_t AudioFlinger::PlaybackThread::Track::getVolumeLR()
{
    // called by FastMixer, so not allowed to take any locks, block, or do I/O including logs
    ALOG_ASSERT(isFastTrack() && (mCblk != NULL));
    gain_minifloat_packed_t vlr = mAudioTrackServerProxy->getVolumeLR();
    float vl = float_from_gain(gain_minifloat_unpack_left(vlr));
    float vr = float_from_gain(gain_minifloat_unpack_right(vlr));
    // track volumes come from shared memory, so can't be trusted and must be clamped
    if (vl > GAIN_FLOAT_UNITY) {
        vl = GAIN_FLOAT_UNITY;
    }
    if (vr > GAIN_FLOAT_UNITY) {
        vr = GAIN_FLOAT_UNITY;
    }
    // now apply the cached master volume and stream type volume;
    // this is trusted but lacks any synchronization or barrier so may be stale
    float v = mCachedVolume;
    vl *= v;
    vr *= v;
    // re-combine into packed minifloat
    vlr = gain_minifloat_pack(gain_from_float(vl), gain_from_float(vr));
    // FIXME look at mute, pause, and stop flags
    return vlr;
}

status_t AudioFlinger::PlaybackThread::Track::setSyncEvent(const sp<SyncEvent>& event)
{
    if (isTerminated() || mState == PAUSED ||
            ((framesReady() == 0) && ((mSharedBuffer != 0) ||
                                      (mState == STOPPED)))) {
        ALOGW("Track::setSyncEvent() in invalid state %d on session %d %s mode, framesReady %zu",
              mState, mSessionId, (mSharedBuffer != 0) ? "static" : "stream", framesReady());
        event->cancel();
        return INVALID_OPERATION;
    }
    (void) TrackBase::setSyncEvent(event);
    return NO_ERROR;
}

void AudioFlinger::PlaybackThread::Track::invalidate()
{
    TrackBase::invalidate();
    signalClientFlag(CBLK_INVALID);
}

void AudioFlinger::PlaybackThread::Track::disable()
{
    signalClientFlag(CBLK_DISABLED);
}

void AudioFlinger::PlaybackThread::Track::signalClientFlag(int32_t flag)
{
    // FIXME should use proxy, and needs work
    audio_track_cblk_t* cblk = mCblk;
    android_atomic_or(flag, &cblk->mFlags);
    android_atomic_release_store(0x40000000, &cblk->mFutex);
    // client is not in server, so FUTEX_WAKE is needed instead of FUTEX_WAKE_PRIVATE
    (void) syscall(__NR_futex, &cblk->mFutex, FUTEX_WAKE, INT_MAX);
}

void AudioFlinger::PlaybackThread::Track::signal()
{
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        PlaybackThread *t = (PlaybackThread *)thread.get();
        Mutex::Autolock _l(t->mLock);
        t->broadcast_l();
    }
}

//To be called with thread lock held
bool AudioFlinger::PlaybackThread::Track::isResumePending() {

    if (mState == RESUMING)
        return true;
    /* Resume is pending if track was stopping before pause was called */
    if (mState == STOPPING_1 &&
        mResumeToStopping)
        return true;

    return false;
}

//To be called with thread lock held
void AudioFlinger::PlaybackThread::Track::resumeAck() {


    if (mState == RESUMING)
        mState = ACTIVE;

    // Other possibility of  pending resume is stopping_1 state
    // Do not update the state from stopping as this prevents
    // drain being called.
    if (mState == STOPPING_1) {
        mResumeToStopping = false;
    }
}

//To be called with thread lock held
void AudioFlinger::PlaybackThread::Track::updateTrackFrameInfo(
        int64_t trackFramesReleased, int64_t sinkFramesWritten,
        const ExtendedTimestamp &timeStamp) {
    //update frame map
    mFrameMap.push(trackFramesReleased, sinkFramesWritten);

    // adjust server times and set drained state.
    //
    // Our timestamps are only updated when the track is on the Thread active list.
    // We need to ensure that tracks are not removed before full drain.
    ExtendedTimestamp local = timeStamp;
    bool checked = false;
    for (int i = ExtendedTimestamp::LOCATION_MAX - 1;
            i >= ExtendedTimestamp::LOCATION_SERVER; --i) {
        // Lookup the track frame corresponding to the sink frame position.
        if (local.mTimeNs[i] > 0) {
            local.mPosition[i] = mFrameMap.findX(local.mPosition[i]);
            // check drain state from the latest stage in the pipeline.
            if (!checked && i <= ExtendedTimestamp::LOCATION_KERNEL) {
                mAudioTrackServerProxy->setDrained(
                        local.mPosition[i] >= mAudioTrackServerProxy->framesReleased());
                checked = true;
            }
        }
    }
    if (!checked) { // no server info, assume drained.
        mAudioTrackServerProxy->setDrained(true);
    }
    // Set correction for flushed frames that are not accounted for in released.
    local.mFlushed = mAudioTrackServerProxy->framesFlushed();
    mServerProxy->setTimestamp(local);
}

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

AudioFlinger::PlaybackThread::OutputTrack::OutputTrack(
            PlaybackThread *playbackThread,
            DuplicatingThread *sourceThread,
            uint32_t sampleRate,
            audio_format_t format,
            audio_channel_mask_t channelMask,
            size_t frameCount,
            uid_t uid)
    :   Track(playbackThread, NULL, AUDIO_STREAM_PATCH,
              sampleRate, format, channelMask, frameCount,
              NULL, 0, AUDIO_SESSION_NONE, uid, AUDIO_OUTPUT_FLAG_NONE,
              TYPE_OUTPUT),
    mActive(false), mSourceThread(sourceThread)
{

    if (mCblk != NULL) {
        mOutBuffer.frameCount = 0;
        playbackThread->mTracks.add(this);
        ALOGV("OutputTrack constructor mCblk %p, mBuffer %p, "
                "frameCount %zu, mChannelMask 0x%08x",
                mCblk, mBuffer,
                frameCount, mChannelMask);
        // since client and server are in the same process,
        // the buffer has the same virtual address on both sides
        mClientProxy = new AudioTrackClientProxy(mCblk, mBuffer, mFrameCount, mFrameSize,
                true /*clientInServer*/);
        mClientProxy->setVolumeLR(GAIN_MINIFLOAT_PACKED_UNITY);
        mClientProxy->setSendLevel(0.0);
        mClientProxy->setSampleRate(sampleRate);
    } else {
        ALOGW("Error creating output track on thread %p", playbackThread);
    }
}

AudioFlinger::PlaybackThread::OutputTrack::~OutputTrack()
{
    clearBufferQueue();
    // superclass destructor will now delete the server proxy and shared memory both refer to
}

status_t AudioFlinger::PlaybackThread::OutputTrack::start(AudioSystem::sync_event_t event,
                                                          audio_session_t triggerSession)
{
    status_t status = Track::start(event, triggerSession);
    if (status != NO_ERROR) {
        return status;
    }

    mActive = true;
    mRetryCount = 127;
    return status;
}

void AudioFlinger::PlaybackThread::OutputTrack::stop()
{
    Track::stop();
    clearBufferQueue();
    mOutBuffer.frameCount = 0;
    mActive = false;
}

bool AudioFlinger::PlaybackThread::OutputTrack::write(void* data, uint32_t frames)
{
    Buffer *pInBuffer;
    Buffer inBuffer;
    bool outputBufferFull = false;
    inBuffer.frameCount = frames;
    inBuffer.raw = data;

    uint32_t waitTimeLeftMs = mSourceThread->waitTimeMs();

    if (!mActive && frames != 0) {
        (void) start();
    }

    while (waitTimeLeftMs) {
        // First write pending buffers, then new data
        if (mBufferQueue.size()) {
            pInBuffer = mBufferQueue.itemAt(0);
        } else {
            pInBuffer = &inBuffer;
        }

        if (pInBuffer->frameCount == 0) {
            break;
        }

        if (mOutBuffer.frameCount == 0) {
            mOutBuffer.frameCount = pInBuffer->frameCount;
            nsecs_t startTime = systemTime();
            status_t status = obtainBuffer(&mOutBuffer, waitTimeLeftMs);
            if (status != NO_ERROR && status != NOT_ENOUGH_DATA) {
                ALOGV("OutputTrack::write() %p thread %p no more output buffers; status %d", this,
                        mThread.unsafe_get(), status);
                outputBufferFull = true;
                break;
            }
            uint32_t waitTimeMs = (uint32_t)ns2ms(systemTime() - startTime);
            if (waitTimeLeftMs >= waitTimeMs) {
                waitTimeLeftMs -= waitTimeMs;
            } else {
                waitTimeLeftMs = 0;
            }
            if (status == NOT_ENOUGH_DATA) {
                restartIfDisabled();
                continue;
            }
        }

        uint32_t outFrames = pInBuffer->frameCount > mOutBuffer.frameCount ? mOutBuffer.frameCount :
                pInBuffer->frameCount;
        memcpy(mOutBuffer.raw, pInBuffer->raw, outFrames * mFrameSize);
        Proxy::Buffer buf;
        buf.mFrameCount = outFrames;
        buf.mRaw = NULL;
        mClientProxy->releaseBuffer(&buf);
        restartIfDisabled();
        pInBuffer->frameCount -= outFrames;
        pInBuffer->raw = (int8_t *)pInBuffer->raw + outFrames * mFrameSize;
        mOutBuffer.frameCount -= outFrames;
        mOutBuffer.raw = (int8_t *)mOutBuffer.raw + outFrames * mFrameSize;

        if (pInBuffer->frameCount == 0) {
            if (mBufferQueue.size()) {
                mBufferQueue.removeAt(0);
                free(pInBuffer->mBuffer);
                if (pInBuffer != &inBuffer) {
                    delete pInBuffer;
                }
                ALOGV("OutputTrack::write() %p thread %p released overflow buffer %zu", this,
                        mThread.unsafe_get(), mBufferQueue.size());
            } else {
                break;
            }
        }
    }

    // If we could not write all frames, allocate a buffer and queue it for next time.
    if (inBuffer.frameCount) {
        sp<ThreadBase> thread = mThread.promote();
        if (thread != 0 && !thread->standby()) {
            if (mBufferQueue.size() < kMaxOverFlowBuffers) {
                pInBuffer = new Buffer;
                pInBuffer->mBuffer = malloc(inBuffer.frameCount * mFrameSize);
                pInBuffer->frameCount = inBuffer.frameCount;
                pInBuffer->raw = pInBuffer->mBuffer;
                memcpy(pInBuffer->raw, inBuffer.raw, inBuffer.frameCount * mFrameSize);
                mBufferQueue.add(pInBuffer);
                ALOGV("OutputTrack::write() %p thread %p adding overflow buffer %zu", this,
                        mThread.unsafe_get(), mBufferQueue.size());
            } else {
                ALOGW("OutputTrack::write() %p thread %p no more overflow buffers",
                        mThread.unsafe_get(), this);
            }
        }
    }

    // Calling write() with a 0 length buffer means that no more data will be written:
    // We rely on stop() to set the appropriate flags to allow the remaining frames to play out.
    if (frames == 0 && mBufferQueue.size() == 0 && mActive) {
        stop();
    }

    return outputBufferFull;
}

status_t AudioFlinger::PlaybackThread::OutputTrack::obtainBuffer(
        AudioBufferProvider::Buffer* buffer, uint32_t waitTimeMs)
{
    ClientProxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    struct timespec timeout;
    timeout.tv_sec = waitTimeMs / 1000;
    timeout.tv_nsec = (int) (waitTimeMs % 1000) * 1000000;
    status_t status = mClientProxy->obtainBuffer(&buf, &timeout);
    buffer->frameCount = buf.mFrameCount;
    buffer->raw = buf.mRaw;
    return status;
}

void AudioFlinger::PlaybackThread::OutputTrack::clearBufferQueue()
{
    size_t size = mBufferQueue.size();

    for (size_t i = 0; i < size; i++) {
        Buffer *pBuffer = mBufferQueue.itemAt(i);
        free(pBuffer->mBuffer);
        delete pBuffer;
    }
    mBufferQueue.clear();
}

void AudioFlinger::PlaybackThread::OutputTrack::restartIfDisabled()
{
    int32_t flags = android_atomic_and(~CBLK_DISABLED, &mCblk->mFlags);
    if (mActive && (flags & CBLK_DISABLED)) {
        start();
    }
}

AudioFlinger::PlaybackThread::PatchTrack::PatchTrack(PlaybackThread *playbackThread,
                                                     audio_stream_type_t streamType,
                                                     uint32_t sampleRate,
                                                     audio_channel_mask_t channelMask,
                                                     audio_format_t format,
                                                     size_t frameCount,
                                                     void *buffer,
                                                     audio_output_flags_t flags)
    :   Track(playbackThread, NULL, streamType,
              sampleRate, format, channelMask, frameCount,
              buffer, 0, AUDIO_SESSION_NONE, getuid(), flags, TYPE_PATCH),
              mProxy(new ClientProxy(mCblk, mBuffer, frameCount, mFrameSize, true, true))
{
    uint64_t mixBufferNs = ((uint64_t)2 * playbackThread->frameCount() * 1000000000) /
                                                                    playbackThread->sampleRate();
    mPeerTimeout.tv_sec = mixBufferNs / 1000000000;
    mPeerTimeout.tv_nsec = (int) (mixBufferNs % 1000000000);

    ALOGV("PatchTrack %p sampleRate %d mPeerTimeout %d.%03d sec",
                                      this, sampleRate,
                                      (int)mPeerTimeout.tv_sec,
                                      (int)(mPeerTimeout.tv_nsec / 1000000));
}

AudioFlinger::PlaybackThread::PatchTrack::~PatchTrack()
{
}

status_t AudioFlinger::PlaybackThread::PatchTrack::start(AudioSystem::sync_event_t event,
                                                          audio_session_t triggerSession)
{
    status_t status = Track::start(event, triggerSession);
    if (status != NO_ERROR) {
        return status;
    }
    android_atomic_and(~CBLK_DISABLED, &mCblk->mFlags);
    return status;
}

// AudioBufferProvider interface
status_t AudioFlinger::PlaybackThread::PatchTrack::getNextBuffer(
        AudioBufferProvider::Buffer* buffer)
{
    ALOG_ASSERT(mPeerProxy != 0, "PatchTrack::getNextBuffer() called without peer proxy");
    Proxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    status_t status = mPeerProxy->obtainBuffer(&buf, &mPeerTimeout);
    ALOGV_IF(status != NO_ERROR, "PatchTrack() %p getNextBuffer status %d", this, status);
    buffer->frameCount = buf.mFrameCount;
    if (buf.mFrameCount == 0) {
        return WOULD_BLOCK;
    }
    status = Track::getNextBuffer(buffer);
    return status;
}

void AudioFlinger::PlaybackThread::PatchTrack::releaseBuffer(AudioBufferProvider::Buffer* buffer)
{
    ALOG_ASSERT(mPeerProxy != 0, "PatchTrack::releaseBuffer() called without peer proxy");
    Proxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    buf.mRaw = buffer->raw;
    mPeerProxy->releaseBuffer(&buf);
    TrackBase::releaseBuffer(buffer);
}

status_t AudioFlinger::PlaybackThread::PatchTrack::obtainBuffer(Proxy::Buffer* buffer,
                                                                const struct timespec *timeOut)
{
    status_t status = NO_ERROR;
    static const int32_t kMaxTries = 5;
    int32_t tryCounter = kMaxTries;
    do {
        if (status == NOT_ENOUGH_DATA) {
            restartIfDisabled();
        }
        status = mProxy->obtainBuffer(buffer, timeOut);
    } while ((status == NOT_ENOUGH_DATA) && (tryCounter-- > 0));
    return status;
}

void AudioFlinger::PlaybackThread::PatchTrack::releaseBuffer(Proxy::Buffer* buffer)
{
    mProxy->releaseBuffer(buffer);
    restartIfDisabled();
    android_atomic_or(CBLK_FORCEREADY, &mCblk->mFlags);
}

void AudioFlinger::PlaybackThread::PatchTrack::restartIfDisabled()
{
    if (android_atomic_and(~CBLK_DISABLED, &mCblk->mFlags) & CBLK_DISABLED) {
        ALOGW("PatchTrack::releaseBuffer() disabled due to previous underrun, restarting");
        start();
    }
}

// ----------------------------------------------------------------------------
//      Record
// ----------------------------------------------------------------------------

AudioFlinger::RecordHandle::RecordHandle(
        const sp<AudioFlinger::RecordThread::RecordTrack>& recordTrack)
    : BnAudioRecord(),
    mRecordTrack(recordTrack)
{
}

AudioFlinger::RecordHandle::~RecordHandle() {
    stop_nonvirtual();
    mRecordTrack->destroy();
}

status_t AudioFlinger::RecordHandle::start(int /*AudioSystem::sync_event_t*/ event,
        audio_session_t triggerSession) {
    ALOGV("RecordHandle::start()");
    return mRecordTrack->start((AudioSystem::sync_event_t)event, triggerSession);
}

void AudioFlinger::RecordHandle::stop() {
    stop_nonvirtual();
}

void AudioFlinger::RecordHandle::stop_nonvirtual() {
    ALOGV("RecordHandle::stop()");
    mRecordTrack->stop();
}

status_t AudioFlinger::RecordHandle::onTransact(
    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
{
    return BnAudioRecord::onTransact(code, data, reply, flags);
}

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

// RecordTrack constructor must be called with AudioFlinger::mLock and ThreadBase::mLock held
AudioFlinger::RecordThread::RecordTrack::RecordTrack(
            RecordThread *thread,
            const sp<Client>& client,
            uint32_t sampleRate,
            audio_format_t format,
            audio_channel_mask_t channelMask,
            size_t frameCount,
            void *buffer,
            audio_session_t sessionId,
            uid_t uid,
            audio_input_flags_t flags,
            track_type type,
            audio_port_handle_t portId)
    :   TrackBase(thread, client, sampleRate, format,
                  channelMask, frameCount, buffer, sessionId, uid, false /*isOut*/,
                  (type == TYPE_DEFAULT) ?
                          ((flags & AUDIO_INPUT_FLAG_FAST) ? ALLOC_PIPE : ALLOC_CBLK) :
                          ((buffer == NULL) ? ALLOC_LOCAL : ALLOC_NONE),
                  type, portId),
        mOverflow(false),
        mFramesToDrop(0),
        mResamplerBufferProvider(NULL), // initialize in case of early constructor exit
        mRecordBufferConverter(NULL),
        mFlags(flags)
{
    if (mCblk == NULL) {
        return;
    }

    mRecordBufferConverter = new RecordBufferConverter(
            thread->mChannelMask, thread->mFormat, thread->mSampleRate,
            channelMask, format, sampleRate);
    // Check if the RecordBufferConverter construction was successful.
    // If not, don't continue with construction.
    //
    // NOTE: It would be extremely rare that the record track cannot be created
    // for the current device, but a pending or future device change would make
    // the record track configuration valid.
    if (mRecordBufferConverter->initCheck() != NO_ERROR) {
        ALOGE("RecordTrack unable to create record buffer converter");
        return;
    }

    mServerProxy = new AudioRecordServerProxy(mCblk, mBuffer, frameCount,
            mFrameSize, !isExternalTrack());

    mResamplerBufferProvider = new ResamplerBufferProvider(this);

    if (flags & AUDIO_INPUT_FLAG_FAST) {
        ALOG_ASSERT(thread->mFastTrackAvail);
        thread->mFastTrackAvail = false;
    }
}

AudioFlinger::RecordThread::RecordTrack::~RecordTrack()
{
    ALOGV("%s", __func__);
    delete mRecordBufferConverter;
    delete mResamplerBufferProvider;
}

status_t AudioFlinger::RecordThread::RecordTrack::initCheck() const
{
    status_t status = TrackBase::initCheck();
    if (status == NO_ERROR && mServerProxy == 0) {
        status = BAD_VALUE;
    }
    return status;
}

// AudioBufferProvider interface
status_t AudioFlinger::RecordThread::RecordTrack::getNextBuffer(AudioBufferProvider::Buffer* buffer)
{
    ServerProxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    status_t status = mServerProxy->obtainBuffer(&buf);
    buffer->frameCount = buf.mFrameCount;
    buffer->raw = buf.mRaw;
    if (buf.mFrameCount == 0) {
        // FIXME also wake futex so that overrun is noticed more quickly
        (void) android_atomic_or(CBLK_OVERRUN, &mCblk->mFlags);
    }
    return status;
}

status_t AudioFlinger::RecordThread::RecordTrack::start(AudioSystem::sync_event_t event,
                                                        audio_session_t triggerSession)
{
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        RecordThread *recordThread = (RecordThread *)thread.get();
        return recordThread->start(this, event, triggerSession);
    } else {
        return BAD_VALUE;
    }
}

void AudioFlinger::RecordThread::RecordTrack::stop()
{
    sp<ThreadBase> thread = mThread.promote();
    if (thread != 0) {
        RecordThread *recordThread = (RecordThread *)thread.get();
        if (recordThread->stop(this) && isExternalTrack()) {
            AudioSystem::stopInput(mThreadIoHandle, mSessionId);
        }
    }
}

void AudioFlinger::RecordThread::RecordTrack::destroy()
{
    // see comments at AudioFlinger::PlaybackThread::Track::destroy()
    sp<RecordTrack> keep(this);
    {
        if (isExternalTrack()) {
            if (mState == ACTIVE || mState == RESUMING) {
                AudioSystem::stopInput(mThreadIoHandle, mSessionId);
            }
            AudioSystem::releaseInput(mThreadIoHandle, mSessionId);
        }
        sp<ThreadBase> thread = mThread.promote();
        if (thread != 0) {
            Mutex::Autolock _l(thread->mLock);
            RecordThread *recordThread = (RecordThread *) thread.get();
            recordThread->destroyTrack_l(this);
        }
    }
}

void AudioFlinger::RecordThread::RecordTrack::invalidate()
{
    TrackBase::invalidate();
    // FIXME should use proxy, and needs work
    audio_track_cblk_t* cblk = mCblk;
    android_atomic_or(CBLK_INVALID, &cblk->mFlags);
    android_atomic_release_store(0x40000000, &cblk->mFutex);
    // client is not in server, so FUTEX_WAKE is needed instead of FUTEX_WAKE_PRIVATE
    (void) syscall(__NR_futex, &cblk->mFutex, FUTEX_WAKE, INT_MAX);
}


/*static*/ void AudioFlinger::RecordThread::RecordTrack::appendDumpHeader(String8& result)
{
    result.append("    Active Client Fmt Chn mask Session S   Server fCount SRate\n");
}

void AudioFlinger::RecordThread::RecordTrack::dump(char* buffer, size_t size, bool active)
{
    snprintf(buffer, size, "    %6s %6u %3u %08X %7u %1d %08X %6zu %5u\n",
            active ? "yes" : "no",
            (mClient == 0) ? getpid_cached : mClient->pid(),
            mFormat,
            mChannelMask,
            mSessionId,
            mState,
            mCblk->mServer,
            mFrameCount,
            mSampleRate);

}

void AudioFlinger::RecordThread::RecordTrack::handleSyncStartEvent(const sp<SyncEvent>& event)
{
    if (event == mSyncStartEvent) {
        ssize_t framesToDrop = 0;
        sp<ThreadBase> threadBase = mThread.promote();
        if (threadBase != 0) {
            // TODO: use actual buffer filling status instead of 2 buffers when info is available
            // from audio HAL
            framesToDrop = threadBase->mFrameCount * 2;
        }
        mFramesToDrop = framesToDrop;
    }
}

void AudioFlinger::RecordThread::RecordTrack::clearSyncStartEvent()
{
    if (mSyncStartEvent != 0) {
        mSyncStartEvent->cancel();
        mSyncStartEvent.clear();
    }
    mFramesToDrop = 0;
}

void AudioFlinger::RecordThread::RecordTrack::updateTrackFrameInfo(
        int64_t trackFramesReleased, int64_t sourceFramesRead,
        uint32_t halSampleRate, const ExtendedTimestamp &timestamp)
{
    ExtendedTimestamp local = timestamp;

    // Convert HAL frames to server-side track frames at track sample rate.
    // We use trackFramesReleased and sourceFramesRead as an anchor point.
    for (int i = ExtendedTimestamp::LOCATION_SERVER; i < ExtendedTimestamp::LOCATION_MAX; ++i) {
        if (local.mTimeNs[i] != 0) {
            const int64_t relativeServerFrames = local.mPosition[i] - sourceFramesRead;
            const int64_t relativeTrackFrames = relativeServerFrames
                    * mSampleRate / halSampleRate; // TODO: potential computation overflow
            local.mPosition[i] = relativeTrackFrames + trackFramesReleased;
        }
    }
    mServerProxy->setTimestamp(local);
}

AudioFlinger::RecordThread::PatchRecord::PatchRecord(RecordThread *recordThread,
                                                     uint32_t sampleRate,
                                                     audio_channel_mask_t channelMask,
                                                     audio_format_t format,
                                                     size_t frameCount,
                                                     void *buffer,
                                                     audio_input_flags_t flags)
    :   RecordTrack(recordThread, NULL, sampleRate, format, channelMask, frameCount,
                buffer, AUDIO_SESSION_NONE, getuid(), flags, TYPE_PATCH),
                mProxy(new ClientProxy(mCblk, mBuffer, frameCount, mFrameSize, false, true))
{
    uint64_t mixBufferNs = ((uint64_t)2 * recordThread->frameCount() * 1000000000) /
                                                                recordThread->sampleRate();
    mPeerTimeout.tv_sec = mixBufferNs / 1000000000;
    mPeerTimeout.tv_nsec = (int) (mixBufferNs % 1000000000);

    ALOGV("PatchRecord %p sampleRate %d mPeerTimeout %d.%03d sec",
                                      this, sampleRate,
                                      (int)mPeerTimeout.tv_sec,
                                      (int)(mPeerTimeout.tv_nsec / 1000000));
}

AudioFlinger::RecordThread::PatchRecord::~PatchRecord()
{
}

// AudioBufferProvider interface
status_t AudioFlinger::RecordThread::PatchRecord::getNextBuffer(
                                                  AudioBufferProvider::Buffer* buffer)
{
    ALOG_ASSERT(mPeerProxy != 0, "PatchRecord::getNextBuffer() called without peer proxy");
    Proxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    status_t status = mPeerProxy->obtainBuffer(&buf, &mPeerTimeout);
    ALOGV_IF(status != NO_ERROR,
             "PatchRecord() %p mPeerProxy->obtainBuffer status %d", this, status);
    buffer->frameCount = buf.mFrameCount;
    if (buf.mFrameCount == 0) {
        return WOULD_BLOCK;
    }
    status = RecordTrack::getNextBuffer(buffer);
    return status;
}

void AudioFlinger::RecordThread::PatchRecord::releaseBuffer(AudioBufferProvider::Buffer* buffer)
{
    ALOG_ASSERT(mPeerProxy != 0, "PatchRecord::releaseBuffer() called without peer proxy");
    Proxy::Buffer buf;
    buf.mFrameCount = buffer->frameCount;
    buf.mRaw = buffer->raw;
    mPeerProxy->releaseBuffer(&buf);
    TrackBase::releaseBuffer(buffer);
}

status_t AudioFlinger::RecordThread::PatchRecord::obtainBuffer(Proxy::Buffer* buffer,
                                                               const struct timespec *timeOut)
{
    return mProxy->obtainBuffer(buffer, timeOut);
}

void AudioFlinger::RecordThread::PatchRecord::releaseBuffer(Proxy::Buffer* buffer)
{
    mProxy->releaseBuffer(buffer);
}



AudioFlinger::MmapThread::MmapTrack::MmapTrack(ThreadBase *thread,
        uint32_t sampleRate,
        audio_format_t format,
        audio_channel_mask_t channelMask,
        audio_session_t sessionId,
        uid_t uid,
        audio_port_handle_t portId)
    :   TrackBase(thread, NULL, sampleRate, format,
                  channelMask, 0, NULL, sessionId, uid, false,
                  ALLOC_NONE,
                  TYPE_DEFAULT, portId)
{
}

AudioFlinger::MmapThread::MmapTrack::~MmapTrack()
{
}

status_t AudioFlinger::MmapThread::MmapTrack::initCheck() const
{
    return NO_ERROR;
}

status_t AudioFlinger::MmapThread::MmapTrack::start(AudioSystem::sync_event_t event __unused,
                                                        audio_session_t triggerSession __unused)
{
    return NO_ERROR;
}

void AudioFlinger::MmapThread::MmapTrack::stop()
{
}

// AudioBufferProvider interface
status_t AudioFlinger::MmapThread::MmapTrack::getNextBuffer(AudioBufferProvider::Buffer* buffer)
{
    buffer->frameCount = 0;
    buffer->raw = nullptr;
    return INVALID_OPERATION;
}

// ExtendedAudioBufferProvider interface
size_t AudioFlinger::MmapThread::MmapTrack::framesReady() const {
    return 0;
}

int64_t AudioFlinger::MmapThread::MmapTrack::framesReleased() const
{
    return 0;
}

void AudioFlinger::MmapThread::MmapTrack::onTimestamp(const ExtendedTimestamp &timestamp __unused)
{
}

/*static*/ void AudioFlinger::MmapThread::MmapTrack::appendDumpHeader(String8& result)
{
    result.append("    Client Fmt Chn mask  SRate\n");
}

void AudioFlinger::MmapThread::MmapTrack::dump(char* buffer, size_t size)
{
    snprintf(buffer, size, "            %6u %3u    %08X %5u\n",
            mUid,
            mFormat,
            mChannelMask,
            mSampleRate);

}

} // namespace android