AudioTrack.cpp revision 4f9b0c54011eb8fd2ccfb393c2dcd51cd07800e0 
1/* frameworks/base/media/libmedia/AudioTrack.cpp
2**
3** Copyright 2007, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18
19//#define LOG_NDEBUG 0
20#define LOG_TAG "AudioTrack"
21
22#include <stdint.h>
23#include <sys/types.h>
24#include <limits.h>
25
26#include <sched.h>
27#include <sys/resource.h>
28
29#include <private/media/AudioTrackShared.h>
30
31#include <media/AudioSystem.h>
32#include <media/AudioTrack.h>
33
34#include <utils/Log.h>
35#include <binder/Parcel.h>
36#include <binder/IPCThreadState.h>
37#include <utils/Timers.h>
38#include <utils/Atomic.h>
39
40#include <cutils/bitops.h>
41#include <cutils/compiler.h>
42
43#include <system/audio.h>
44#include <system/audio_policy.h>
45
46#include <audio_utils/primitives.h>
47
48namespace android {
49// ---------------------------------------------------------------------------
50
51// static
52status_t AudioTrack::getMinFrameCount(
53        int* frameCount,
54        audio_stream_type_t streamType,
55        uint32_t sampleRate)
56{
57    int afSampleRate;
58    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
59        return NO_INIT;
60    }
61    int afFrameCount;
62    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
63        return NO_INIT;
64    }
65    uint32_t afLatency;
66    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
67        return NO_INIT;
68    }
69
70    // Ensure that buffer depth covers at least audio hardware latency
71    uint32_t minBufCount = afLatency / ((1000 * afFrameCount) / afSampleRate);
72    if (minBufCount < 2) minBufCount = 2;
73
74    *frameCount = (sampleRate == 0) ? afFrameCount * minBufCount :
75              afFrameCount * minBufCount * sampleRate / afSampleRate;
76    return NO_ERROR;
77}
78
79// ---------------------------------------------------------------------------
80
81AudioTrack::AudioTrack()
82    : mStatus(NO_INIT),
83      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
84{
85}
86
87AudioTrack::AudioTrack(
88        audio_stream_type_t streamType,
89        uint32_t sampleRate,
90        audio_format_t format,
91        int channelMask,
92        int frameCount,
93        uint32_t flags,
94        callback_t cbf,
95        void* user,
96        int notificationFrames,
97        int sessionId)
98    : mStatus(NO_INIT),
99      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
100{
101    mStatus = set(streamType, sampleRate, format, channelMask,
102            frameCount, flags, cbf, user, notificationFrames,
103            0, false, sessionId);
104}
105
106AudioTrack::AudioTrack(
107        int streamType,
108        uint32_t sampleRate,
109        int format,
110        int channelMask,
111        int frameCount,
112        uint32_t flags,
113        callback_t cbf,
114        void* user,
115        int notificationFrames,
116        int sessionId)
117    : mStatus(NO_INIT),
118      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
119{
120    mStatus = set((audio_stream_type_t)streamType, sampleRate, (audio_format_t)format, channelMask,
121            frameCount, flags, cbf, user, notificationFrames,
122            0, false, sessionId);
123}
124
125AudioTrack::AudioTrack(
126        audio_stream_type_t streamType,
127        uint32_t sampleRate,
128        audio_format_t format,
129        int channelMask,
130        const sp<IMemory>& sharedBuffer,
131        uint32_t flags,
132        callback_t cbf,
133        void* user,
134        int notificationFrames,
135        int sessionId)
136    : mStatus(NO_INIT),
137      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
138{
139    mStatus = set(streamType, sampleRate, format, channelMask,
140            0, flags, cbf, user, notificationFrames,
141            sharedBuffer, false, sessionId);
142}
143
144AudioTrack::~AudioTrack()
145{
146    ALOGV_IF(mSharedBuffer != 0, "Destructor sharedBuffer: %p", mSharedBuffer->pointer());
147
148    if (mStatus == NO_ERROR) {
149        // Make sure that callback function exits in the case where
150        // it is looping on buffer full condition in obtainBuffer().
151        // Otherwise the callback thread will never exit.
152        stop();
153        if (mAudioTrackThread != 0) {
154            mAudioTrackThread->requestExitAndWait();
155            mAudioTrackThread.clear();
156        }
157        mAudioTrack.clear();
158        IPCThreadState::self()->flushCommands();
159        AudioSystem::releaseAudioSessionId(mSessionId);
160    }
161}
162
163status_t AudioTrack::set(
164        audio_stream_type_t streamType,
165        uint32_t sampleRate,
166        audio_format_t format,
167        int channelMask,
168        int frameCount,
169        uint32_t flags,
170        callback_t cbf,
171        void* user,
172        int notificationFrames,
173        const sp<IMemory>& sharedBuffer,
174        bool threadCanCallJava,
175        int sessionId)
176{
177
178    ALOGV_IF(sharedBuffer != 0, "sharedBuffer: %p, size: %d", sharedBuffer->pointer(), sharedBuffer->size());
179
180    AutoMutex lock(mLock);
181    if (mAudioTrack != 0) {
182        ALOGE("Track already in use");
183        return INVALID_OPERATION;
184    }
185
186    int afSampleRate;
187    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
188        return NO_INIT;
189    }
190    uint32_t afLatency;
191    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
192        return NO_INIT;
193    }
194
195    // handle default values first.
196    if (streamType == AUDIO_STREAM_DEFAULT) {
197        streamType = AUDIO_STREAM_MUSIC;
198    }
199    if (sampleRate == 0) {
200        sampleRate = afSampleRate;
201    }
202    // these below should probably come from the audioFlinger too...
203    if (format == AUDIO_FORMAT_DEFAULT) {
204        format = AUDIO_FORMAT_PCM_16_BIT;
205    }
206    if (channelMask == 0) {
207        channelMask = AUDIO_CHANNEL_OUT_STEREO;
208    }
209
210    // validate parameters
211    if (!audio_is_valid_format(format)) {
212        ALOGE("Invalid format");
213        return BAD_VALUE;
214    }
215
216    // force direct flag if format is not linear PCM
217    if (!audio_is_linear_pcm(format)) {
218        flags |= AUDIO_POLICY_OUTPUT_FLAG_DIRECT;
219    }
220
221    if (!audio_is_output_channel(channelMask)) {
222        ALOGE("Invalid channel mask");
223        return BAD_VALUE;
224    }
225    uint32_t channelCount = popcount(channelMask);
226
227    audio_io_handle_t output = AudioSystem::getOutput(
228                                    streamType,
229                                    sampleRate, format, channelMask,
230                                    (audio_policy_output_flags_t)flags);
231
232    if (output == 0) {
233        ALOGE("Could not get audio output for stream type %d", streamType);
234        return BAD_VALUE;
235    }
236
237    mVolume[LEFT] = 1.0f;
238    mVolume[RIGHT] = 1.0f;
239    mSendLevel = 0.0f;
240    mFrameCount = frameCount;
241    mNotificationFramesReq = notificationFrames;
242    mSessionId = sessionId;
243    mAuxEffectId = 0;
244
245    // create the IAudioTrack
246    status_t status = createTrack_l(streamType,
247                                  sampleRate,
248                                  format,
249                                  (uint32_t)channelMask,
250                                  frameCount,
251                                  flags,
252                                  sharedBuffer,
253                                  output,
254                                  true);
255
256    if (status != NO_ERROR) {
257        return status;
258    }
259
260    if (cbf != NULL) {
261        mAudioTrackThread = new AudioTrackThread(*this, threadCanCallJava);
262    }
263
264    mStatus = NO_ERROR;
265
266    mStreamType = streamType;
267    mFormat = format;
268    mChannelMask = (uint32_t)channelMask;
269    mChannelCount = channelCount;
270    mSharedBuffer = sharedBuffer;
271    mMuted = false;
272    mActive = false;
273    mCbf = cbf;
274    mUserData = user;
275    mLoopCount = 0;
276    mMarkerPosition = 0;
277    mMarkerReached = false;
278    mNewPosition = 0;
279    mUpdatePeriod = 0;
280    mFlushed = false;
281    mFlags = flags;
282    AudioSystem::acquireAudioSessionId(mSessionId);
283    mRestoreStatus = NO_ERROR;
284    return NO_ERROR;
285}
286
287status_t AudioTrack::initCheck() const
288{
289    return mStatus;
290}
291
292// -------------------------------------------------------------------------
293
294uint32_t AudioTrack::latency() const
295{
296    return mLatency;
297}
298
299audio_stream_type_t AudioTrack::streamType() const
300{
301    return mStreamType;
302}
303
304audio_format_t AudioTrack::format() const
305{
306    return mFormat;
307}
308
309int AudioTrack::channelCount() const
310{
311    return mChannelCount;
312}
313
314uint32_t AudioTrack::frameCount() const
315{
316    return mCblk->frameCount;
317}
318
319size_t AudioTrack::frameSize() const
320{
321    if (audio_is_linear_pcm(mFormat)) {
322        return channelCount()*audio_bytes_per_sample(mFormat);
323    } else {
324        return sizeof(uint8_t);
325    }
326}
327
328sp<IMemory>& AudioTrack::sharedBuffer()
329{
330    return mSharedBuffer;
331}
332
333// -------------------------------------------------------------------------
334
335void AudioTrack::start()
336{
337    sp<AudioTrackThread> t = mAudioTrackThread;
338    status_t status = NO_ERROR;
339
340    ALOGV("start %p", this);
341    if (t != 0) {
342        if (t->exitPending()) {
343            if (t->requestExitAndWait() == WOULD_BLOCK) {
344                ALOGE("AudioTrack::start called from thread");
345                return;
346            }
347        }
348     }
349
350    AutoMutex lock(mLock);
351    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
352    // while we are accessing the cblk
353    sp <IAudioTrack> audioTrack = mAudioTrack;
354    sp <IMemory> iMem = mCblkMemory;
355    audio_track_cblk_t* cblk = mCblk;
356
357    if (!mActive) {
358        mFlushed = false;
359        mActive = true;
360        mNewPosition = cblk->server + mUpdatePeriod;
361        cblk->lock.lock();
362        cblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
363        cblk->waitTimeMs = 0;
364        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
365        if (t != 0) {
366            t->run("AudioTrackThread", ANDROID_PRIORITY_AUDIO);
367        } else {
368            mPreviousPriority = getpriority(PRIO_PROCESS, 0);
369            mPreviousSchedulingGroup = androidGetThreadSchedulingGroup(0);
370            androidSetThreadPriority(0, ANDROID_PRIORITY_AUDIO);
371        }
372
373        ALOGV("start %p before lock cblk %p", this, mCblk);
374        if (!(cblk->flags & CBLK_INVALID_MSK)) {
375            cblk->lock.unlock();
376            status = mAudioTrack->start();
377            cblk->lock.lock();
378            if (status == DEAD_OBJECT) {
379                android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
380            }
381        }
382        if (cblk->flags & CBLK_INVALID_MSK) {
383            status = restoreTrack_l(cblk, true);
384        }
385        cblk->lock.unlock();
386        if (status != NO_ERROR) {
387            ALOGV("start() failed");
388            mActive = false;
389            if (t != 0) {
390                t->requestExit();
391            } else {
392                setpriority(PRIO_PROCESS, 0, mPreviousPriority);
393                androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
394            }
395        }
396    }
397
398}
399
400void AudioTrack::stop()
401{
402    sp<AudioTrackThread> t = mAudioTrackThread;
403
404    ALOGV("stop %p", this);
405
406    AutoMutex lock(mLock);
407    if (mActive) {
408        mActive = false;
409        mCblk->cv.signal();
410        mAudioTrack->stop();
411        // Cancel loops (If we are in the middle of a loop, playback
412        // would not stop until loopCount reaches 0).
413        setLoop_l(0, 0, 0);
414        // the playback head position will reset to 0, so if a marker is set, we need
415        // to activate it again
416        mMarkerReached = false;
417        // Force flush if a shared buffer is used otherwise audioflinger
418        // will not stop before end of buffer is reached.
419        if (mSharedBuffer != 0) {
420            flush_l();
421        }
422        if (t != 0) {
423            t->requestExit();
424        } else {
425            setpriority(PRIO_PROCESS, 0, mPreviousPriority);
426            androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
427        }
428    }
429
430}
431
432bool AudioTrack::stopped() const
433{
434    AutoMutex lock(mLock);
435    return stopped_l();
436}
437
438void AudioTrack::flush()
439{
440    AutoMutex lock(mLock);
441    flush_l();
442}
443
444// must be called with mLock held
445void AudioTrack::flush_l()
446{
447    ALOGV("flush");
448
449    // clear playback marker and periodic update counter
450    mMarkerPosition = 0;
451    mMarkerReached = false;
452    mUpdatePeriod = 0;
453
454    if (!mActive) {
455        mFlushed = true;
456        mAudioTrack->flush();
457        // Release AudioTrack callback thread in case it was waiting for new buffers
458        // in AudioTrack::obtainBuffer()
459        mCblk->cv.signal();
460    }
461}
462
463void AudioTrack::pause()
464{
465    ALOGV("pause");
466    AutoMutex lock(mLock);
467    if (mActive) {
468        mActive = false;
469        mAudioTrack->pause();
470    }
471}
472
473void AudioTrack::mute(bool e)
474{
475    mAudioTrack->mute(e);
476    mMuted = e;
477}
478
479bool AudioTrack::muted() const
480{
481    return mMuted;
482}
483
484status_t AudioTrack::setVolume(float left, float right)
485{
486    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
487        return BAD_VALUE;
488    }
489
490    AutoMutex lock(mLock);
491    mVolume[LEFT] = left;
492    mVolume[RIGHT] = right;
493
494    mCblk->setVolumeLR((uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000));
495
496    return NO_ERROR;
497}
498
499void AudioTrack::getVolume(float* left, float* right) const
500{
501    if (left != NULL) {
502        *left  = mVolume[LEFT];
503    }
504    if (right != NULL) {
505        *right = mVolume[RIGHT];
506    }
507}
508
509status_t AudioTrack::setAuxEffectSendLevel(float level)
510{
511    ALOGV("setAuxEffectSendLevel(%f)", level);
512    if (level < 0.0f || level > 1.0f) {
513        return BAD_VALUE;
514    }
515    AutoMutex lock(mLock);
516
517    mSendLevel = level;
518
519    mCblk->setSendLevel(level);
520
521    return NO_ERROR;
522}
523
524void AudioTrack::getAuxEffectSendLevel(float* level) const
525{
526    if (level != NULL) {
527        *level  = mSendLevel;
528    }
529}
530
531status_t AudioTrack::setSampleRate(int rate)
532{
533    int afSamplingRate;
534
535    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
536        return NO_INIT;
537    }
538    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
539    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
540
541    AutoMutex lock(mLock);
542    mCblk->sampleRate = rate;
543    return NO_ERROR;
544}
545
546uint32_t AudioTrack::getSampleRate() const
547{
548    AutoMutex lock(mLock);
549    return mCblk->sampleRate;
550}
551
552status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
553{
554    AutoMutex lock(mLock);
555    return setLoop_l(loopStart, loopEnd, loopCount);
556}
557
558// must be called with mLock held
559status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
560{
561    audio_track_cblk_t* cblk = mCblk;
562
563    Mutex::Autolock _l(cblk->lock);
564
565    if (loopCount == 0) {
566        cblk->loopStart = UINT_MAX;
567        cblk->loopEnd = UINT_MAX;
568        cblk->loopCount = 0;
569        mLoopCount = 0;
570        return NO_ERROR;
571    }
572
573    if (loopStart >= loopEnd ||
574        loopEnd - loopStart > cblk->frameCount ||
575        cblk->server > loopStart) {
576        ALOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
577        return BAD_VALUE;
578    }
579
580    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
581        ALOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
582            loopStart, loopEnd, cblk->frameCount);
583        return BAD_VALUE;
584    }
585
586    cblk->loopStart = loopStart;
587    cblk->loopEnd = loopEnd;
588    cblk->loopCount = loopCount;
589    mLoopCount = loopCount;
590
591    return NO_ERROR;
592}
593
594status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount) const
595{
596    AutoMutex lock(mLock);
597    if (loopStart != NULL) {
598        *loopStart = mCblk->loopStart;
599    }
600    if (loopEnd != NULL) {
601        *loopEnd = mCblk->loopEnd;
602    }
603    if (loopCount != NULL) {
604        if (mCblk->loopCount < 0) {
605            *loopCount = -1;
606        } else {
607            *loopCount = mCblk->loopCount;
608        }
609    }
610
611    return NO_ERROR;
612}
613
614status_t AudioTrack::setMarkerPosition(uint32_t marker)
615{
616    if (mCbf == NULL) return INVALID_OPERATION;
617
618    mMarkerPosition = marker;
619    mMarkerReached = false;
620
621    return NO_ERROR;
622}
623
624status_t AudioTrack::getMarkerPosition(uint32_t *marker) const
625{
626    if (marker == NULL) return BAD_VALUE;
627
628    *marker = mMarkerPosition;
629
630    return NO_ERROR;
631}
632
633status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
634{
635    if (mCbf == NULL) return INVALID_OPERATION;
636
637    uint32_t curPosition;
638    getPosition(&curPosition);
639    mNewPosition = curPosition + updatePeriod;
640    mUpdatePeriod = updatePeriod;
641
642    return NO_ERROR;
643}
644
645status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod) const
646{
647    if (updatePeriod == NULL) return BAD_VALUE;
648
649    *updatePeriod = mUpdatePeriod;
650
651    return NO_ERROR;
652}
653
654status_t AudioTrack::setPosition(uint32_t position)
655{
656    AutoMutex lock(mLock);
657
658    if (!stopped_l()) return INVALID_OPERATION;
659
660    Mutex::Autolock _l(mCblk->lock);
661
662    if (position > mCblk->user) return BAD_VALUE;
663
664    mCblk->server = position;
665    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
666
667    return NO_ERROR;
668}
669
670status_t AudioTrack::getPosition(uint32_t *position)
671{
672    if (position == NULL) return BAD_VALUE;
673    AutoMutex lock(mLock);
674    *position = mFlushed ? 0 : mCblk->server;
675
676    return NO_ERROR;
677}
678
679status_t AudioTrack::reload()
680{
681    AutoMutex lock(mLock);
682
683    if (!stopped_l()) return INVALID_OPERATION;
684
685    flush_l();
686
687    mCblk->stepUser(mCblk->frameCount);
688
689    return NO_ERROR;
690}
691
692audio_io_handle_t AudioTrack::getOutput()
693{
694    AutoMutex lock(mLock);
695    return getOutput_l();
696}
697
698// must be called with mLock held
699audio_io_handle_t AudioTrack::getOutput_l()
700{
701    return AudioSystem::getOutput(mStreamType,
702            mCblk->sampleRate, mFormat, mChannelMask, (audio_policy_output_flags_t)mFlags);
703}
704
705int AudioTrack::getSessionId() const
706{
707    return mSessionId;
708}
709
710status_t AudioTrack::attachAuxEffect(int effectId)
711{
712    ALOGV("attachAuxEffect(%d)", effectId);
713    status_t status = mAudioTrack->attachAuxEffect(effectId);
714    if (status == NO_ERROR) {
715        mAuxEffectId = effectId;
716    }
717    return status;
718}
719
720// -------------------------------------------------------------------------
721
722// must be called with mLock held
723status_t AudioTrack::createTrack_l(
724        audio_stream_type_t streamType,
725        uint32_t sampleRate,
726        audio_format_t format,
727        uint32_t channelMask,
728        int frameCount,
729        uint32_t flags,
730        const sp<IMemory>& sharedBuffer,
731        audio_io_handle_t output,
732        bool enforceFrameCount)
733{
734    status_t status;
735    const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
736    if (audioFlinger == 0) {
737       ALOGE("Could not get audioflinger");
738       return NO_INIT;
739    }
740
741    int afSampleRate;
742    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
743        return NO_INIT;
744    }
745    int afFrameCount;
746    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
747        return NO_INIT;
748    }
749    uint32_t afLatency;
750    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
751        return NO_INIT;
752    }
753
754    mNotificationFramesAct = mNotificationFramesReq;
755    if (!audio_is_linear_pcm(format)) {
756        if (sharedBuffer != 0) {
757            frameCount = sharedBuffer->size();
758        }
759    } else {
760        // Ensure that buffer depth covers at least audio hardware latency
761        uint32_t minBufCount = afLatency / ((1000 * afFrameCount)/afSampleRate);
762        if (minBufCount < 2) minBufCount = 2;
763
764        int minFrameCount = (afFrameCount*sampleRate*minBufCount)/afSampleRate;
765
766        if (sharedBuffer == 0) {
767            if (frameCount == 0) {
768                frameCount = minFrameCount;
769            }
770            if (mNotificationFramesAct == 0) {
771                mNotificationFramesAct = frameCount/2;
772            }
773            // Make sure that application is notified with sufficient margin
774            // before underrun
775            if (mNotificationFramesAct > (uint32_t)frameCount/2) {
776                mNotificationFramesAct = frameCount/2;
777            }
778            if (frameCount < minFrameCount) {
779                if (enforceFrameCount) {
780                    ALOGE("Invalid buffer size: minFrameCount %d, frameCount %d", minFrameCount, frameCount);
781                    return BAD_VALUE;
782                } else {
783                    frameCount = minFrameCount;
784                }
785            }
786        } else {
787            // Ensure that buffer alignment matches channelcount
788            int channelCount = popcount(channelMask);
789            if (((uint32_t)sharedBuffer->pointer() & (channelCount | 1)) != 0) {
790                ALOGE("Invalid buffer alignement: address %p, channelCount %d", sharedBuffer->pointer(), channelCount);
791                return BAD_VALUE;
792            }
793            frameCount = sharedBuffer->size()/channelCount/sizeof(int16_t);
794        }
795    }
796
797    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
798                                                      streamType,
799                                                      sampleRate,
800                                                      format,
801                                                      channelMask,
802                                                      frameCount,
803                                                      ((uint16_t)flags) << 16,
804                                                      sharedBuffer,
805                                                      output,
806                                                      &mSessionId,
807                                                      &status);
808
809    if (track == 0) {
810        ALOGE("AudioFlinger could not create track, status: %d", status);
811        return status;
812    }
813    sp<IMemory> cblk = track->getCblk();
814    if (cblk == 0) {
815        ALOGE("Could not get control block");
816        return NO_INIT;
817    }
818    mAudioTrack = track;
819    mCblkMemory = cblk;
820    mCblk = static_cast<audio_track_cblk_t*>(cblk->pointer());
821    android_atomic_or(CBLK_DIRECTION_OUT, &mCblk->flags);
822    if (sharedBuffer == 0) {
823        mCblk->buffers = (char*)mCblk + sizeof(audio_track_cblk_t);
824    } else {
825        mCblk->buffers = sharedBuffer->pointer();
826         // Force buffer full condition as data is already present in shared memory
827        mCblk->stepUser(mCblk->frameCount);
828    }
829
830    mCblk->setVolumeLR((uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000));
831    mCblk->setSendLevel(mSendLevel);
832    mAudioTrack->attachAuxEffect(mAuxEffectId);
833    mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
834    mCblk->waitTimeMs = 0;
835    mRemainingFrames = mNotificationFramesAct;
836    mLatency = afLatency + (1000*mCblk->frameCount) / sampleRate;
837    return NO_ERROR;
838}
839
840status_t AudioTrack::obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
841{
842    AutoMutex lock(mLock);
843    bool active;
844    status_t result = NO_ERROR;
845    audio_track_cblk_t* cblk = mCblk;
846    uint32_t framesReq = audioBuffer->frameCount;
847    uint32_t waitTimeMs = (waitCount < 0) ? cblk->bufferTimeoutMs : WAIT_PERIOD_MS;
848
849    audioBuffer->frameCount  = 0;
850    audioBuffer->size = 0;
851
852    uint32_t framesAvail = cblk->framesAvailable();
853
854    cblk->lock.lock();
855    if (cblk->flags & CBLK_INVALID_MSK) {
856        goto create_new_track;
857    }
858    cblk->lock.unlock();
859
860    if (framesAvail == 0) {
861        cblk->lock.lock();
862        goto start_loop_here;
863        while (framesAvail == 0) {
864            active = mActive;
865            if (CC_UNLIKELY(!active)) {
866                ALOGV("Not active and NO_MORE_BUFFERS");
867                cblk->lock.unlock();
868                return NO_MORE_BUFFERS;
869            }
870            if (CC_UNLIKELY(!waitCount)) {
871                cblk->lock.unlock();
872                return WOULD_BLOCK;
873            }
874            if (!(cblk->flags & CBLK_INVALID_MSK)) {
875                mLock.unlock();
876                result = cblk->cv.waitRelative(cblk->lock, milliseconds(waitTimeMs));
877                cblk->lock.unlock();
878                mLock.lock();
879                if (!mActive) {
880                    return status_t(STOPPED);
881                }
882                cblk->lock.lock();
883            }
884
885            if (cblk->flags & CBLK_INVALID_MSK) {
886                goto create_new_track;
887            }
888            if (CC_UNLIKELY(result != NO_ERROR)) {
889                cblk->waitTimeMs += waitTimeMs;
890                if (cblk->waitTimeMs >= cblk->bufferTimeoutMs) {
891                    // timing out when a loop has been set and we have already written upto loop end
892                    // is a normal condition: no need to wake AudioFlinger up.
893                    if (cblk->user < cblk->loopEnd) {
894                        ALOGW(   "obtainBuffer timed out (is the CPU pegged?) %p "
895                                "user=%08x, server=%08x", this, cblk->user, cblk->server);
896                        //unlock cblk mutex before calling mAudioTrack->start() (see issue #1617140)
897                        cblk->lock.unlock();
898                        result = mAudioTrack->start();
899                        cblk->lock.lock();
900                        if (result == DEAD_OBJECT) {
901                            android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
902create_new_track:
903                            result = restoreTrack_l(cblk, false);
904                        }
905                        if (result != NO_ERROR) {
906                            ALOGW("obtainBuffer create Track error %d", result);
907                            cblk->lock.unlock();
908                            return result;
909                        }
910                    }
911                    cblk->waitTimeMs = 0;
912                }
913
914                if (--waitCount == 0) {
915                    cblk->lock.unlock();
916                    return TIMED_OUT;
917                }
918            }
919            // read the server count again
920        start_loop_here:
921            framesAvail = cblk->framesAvailable_l();
922        }
923        cblk->lock.unlock();
924    }
925
926    // restart track if it was disabled by audioflinger due to previous underrun
927    if (mActive && (cblk->flags & CBLK_DISABLED_MSK)) {
928        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
929        ALOGW("obtainBuffer() track %p disabled, restarting", this);
930        mAudioTrack->start();
931    }
932
933    cblk->waitTimeMs = 0;
934
935    if (framesReq > framesAvail) {
936        framesReq = framesAvail;
937    }
938
939    uint32_t u = cblk->user;
940    uint32_t bufferEnd = cblk->userBase + cblk->frameCount;
941
942    if (u + framesReq > bufferEnd) {
943        framesReq = bufferEnd - u;
944    }
945
946    audioBuffer->flags = mMuted ? Buffer::MUTE : 0;
947    audioBuffer->channelCount = mChannelCount;
948    audioBuffer->frameCount = framesReq;
949    audioBuffer->size = framesReq * cblk->frameSize;
950    if (audio_is_linear_pcm(mFormat)) {
951        audioBuffer->format = AUDIO_FORMAT_PCM_16_BIT;
952    } else {
953        audioBuffer->format = mFormat;
954    }
955    audioBuffer->raw = (int8_t *)cblk->buffer(u);
956    active = mActive;
957    return active ? status_t(NO_ERROR) : status_t(STOPPED);
958}
959
960void AudioTrack::releaseBuffer(Buffer* audioBuffer)
961{
962    AutoMutex lock(mLock);
963    mCblk->stepUser(audioBuffer->frameCount);
964}
965
966// -------------------------------------------------------------------------
967
968ssize_t AudioTrack::write(const void* buffer, size_t userSize)
969{
970
971    if (mSharedBuffer != 0) return INVALID_OPERATION;
972
973    if (ssize_t(userSize) < 0) {
974        // sanity-check. user is most-likely passing an error code.
975        ALOGE("AudioTrack::write(buffer=%p, size=%u (%d)",
976                buffer, userSize, userSize);
977        return BAD_VALUE;
978    }
979
980    ALOGV("write %p: %d bytes, mActive=%d", this, userSize, mActive);
981
982    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
983    // while we are accessing the cblk
984    mLock.lock();
985    sp <IAudioTrack> audioTrack = mAudioTrack;
986    sp <IMemory> iMem = mCblkMemory;
987    mLock.unlock();
988
989    ssize_t written = 0;
990    const int8_t *src = (const int8_t *)buffer;
991    Buffer audioBuffer;
992    size_t frameSz = frameSize();
993
994    do {
995        audioBuffer.frameCount = userSize/frameSz;
996
997        // Calling obtainBuffer() with a negative wait count causes
998        // an (almost) infinite wait time.
999        status_t err = obtainBuffer(&audioBuffer, -1);
1000        if (err < 0) {
1001            // out of buffers, return #bytes written
1002            if (err == status_t(NO_MORE_BUFFERS))
1003                break;
1004            return ssize_t(err);
1005        }
1006
1007        size_t toWrite;
1008
1009        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1010            // Divide capacity by 2 to take expansion into account
1011            toWrite = audioBuffer.size>>1;
1012            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) src, toWrite);
1013        } else {
1014            toWrite = audioBuffer.size;
1015            memcpy(audioBuffer.i8, src, toWrite);
1016            src += toWrite;
1017        }
1018        userSize -= toWrite;
1019        written += toWrite;
1020
1021        releaseBuffer(&audioBuffer);
1022    } while (userSize >= frameSz);
1023
1024    return written;
1025}
1026
1027// -------------------------------------------------------------------------
1028
1029bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1030{
1031    Buffer audioBuffer;
1032    uint32_t frames;
1033    size_t writtenSize;
1034
1035    mLock.lock();
1036    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1037    // while we are accessing the cblk
1038    sp <IAudioTrack> audioTrack = mAudioTrack;
1039    sp <IMemory> iMem = mCblkMemory;
1040    audio_track_cblk_t* cblk = mCblk;
1041    bool active = mActive;
1042    mLock.unlock();
1043
1044    // Manage underrun callback
1045    if (active && (cblk->framesAvailable() == cblk->frameCount)) {
1046        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1047        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1048            mCbf(EVENT_UNDERRUN, mUserData, 0);
1049            if (cblk->server == cblk->frameCount) {
1050                mCbf(EVENT_BUFFER_END, mUserData, 0);
1051            }
1052            if (mSharedBuffer != 0) return false;
1053        }
1054    }
1055
1056    // Manage loop end callback
1057    while (mLoopCount > cblk->loopCount) {
1058        int loopCount = -1;
1059        mLoopCount--;
1060        if (mLoopCount >= 0) loopCount = mLoopCount;
1061
1062        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1063    }
1064
1065    // Manage marker callback
1066    if (!mMarkerReached && (mMarkerPosition > 0)) {
1067        if (cblk->server >= mMarkerPosition) {
1068            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1069            mMarkerReached = true;
1070        }
1071    }
1072
1073    // Manage new position callback
1074    if (mUpdatePeriod > 0) {
1075        while (cblk->server >= mNewPosition) {
1076            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1077            mNewPosition += mUpdatePeriod;
1078        }
1079    }
1080
1081    // If Shared buffer is used, no data is requested from client.
1082    if (mSharedBuffer != 0) {
1083        frames = 0;
1084    } else {
1085        frames = mRemainingFrames;
1086    }
1087
1088    int32_t waitCount = -1;
1089    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1090        waitCount = 1;
1091    }
1092
1093    do {
1094
1095        audioBuffer.frameCount = frames;
1096
1097        // Calling obtainBuffer() with a wait count of 1
1098        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1099        // stuck here not being able to handle timed events (position, markers, loops).
1100        status_t err = obtainBuffer(&audioBuffer, waitCount);
1101        if (err < NO_ERROR) {
1102            if (err != TIMED_OUT) {
1103                ALOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1104                return false;
1105            }
1106            break;
1107        }
1108        if (err == status_t(STOPPED)) return false;
1109
1110        // Divide buffer size by 2 to take into account the expansion
1111        // due to 8 to 16 bit conversion: the callback must fill only half
1112        // of the destination buffer
1113        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1114            audioBuffer.size >>= 1;
1115        }
1116
1117        size_t reqSize = audioBuffer.size;
1118        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1119        writtenSize = audioBuffer.size;
1120
1121        // Sanity check on returned size
1122        if (ssize_t(writtenSize) <= 0) {
1123            // The callback is done filling buffers
1124            // Keep this thread going to handle timed events and
1125            // still try to get more data in intervals of WAIT_PERIOD_MS
1126            // but don't just loop and block the CPU, so wait
1127            usleep(WAIT_PERIOD_MS*1000);
1128            break;
1129        }
1130        if (writtenSize > reqSize) writtenSize = reqSize;
1131
1132        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1133            // 8 to 16 bit conversion, note that source and destination are the same address
1134            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) audioBuffer.i8, writtenSize);
1135            writtenSize <<= 1;
1136        }
1137
1138        audioBuffer.size = writtenSize;
1139        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1140        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
1141        // 16 bit.
1142        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1143
1144        frames -= audioBuffer.frameCount;
1145
1146        releaseBuffer(&audioBuffer);
1147    }
1148    while (frames);
1149
1150    if (frames == 0) {
1151        mRemainingFrames = mNotificationFramesAct;
1152    } else {
1153        mRemainingFrames = frames;
1154    }
1155    return true;
1156}
1157
1158// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1159// the IAudioTrack and IMemory in case they are recreated here.
1160// If the IAudioTrack is successfully restored, the cblk pointer is updated
1161status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1162{
1163    status_t result;
1164
1165    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1166        ALOGW("dead IAudioTrack, creating a new one from %s TID %d",
1167             fromStart ? "start()" : "obtainBuffer()", gettid());
1168
1169        // signal old cblk condition so that other threads waiting for available buffers stop
1170        // waiting now
1171        cblk->cv.broadcast();
1172        cblk->lock.unlock();
1173
1174        // refresh the audio configuration cache in this process to make sure we get new
1175        // output parameters in getOutput_l() and createTrack_l()
1176        AudioSystem::clearAudioConfigCache();
1177
1178        // if the new IAudioTrack is created, createTrack_l() will modify the
1179        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1180        // It will also delete the strong references on previous IAudioTrack and IMemory
1181        result = createTrack_l(mStreamType,
1182                               cblk->sampleRate,
1183                               mFormat,
1184                               mChannelMask,
1185                               mFrameCount,
1186                               mFlags,
1187                               mSharedBuffer,
1188                               getOutput_l(),
1189                               false);
1190
1191        if (result == NO_ERROR) {
1192            uint32_t user = cblk->user;
1193            uint32_t server = cblk->server;
1194            // restore write index and set other indexes to reflect empty buffer status
1195            mCblk->user = user;
1196            mCblk->server = user;
1197            mCblk->userBase = user;
1198            mCblk->serverBase = user;
1199            // restore loop: this is not guaranteed to succeed if new frame count is not
1200            // compatible with loop length
1201            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1202            if (!fromStart) {
1203                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1204                // Make sure that a client relying on callback events indicating underrun or
1205                // the actual amount of audio frames played (e.g SoundPool) receives them.
1206                if (mSharedBuffer == 0) {
1207                    uint32_t frames = 0;
1208                    if (user > server) {
1209                        frames = ((user - server) > mCblk->frameCount) ?
1210                                mCblk->frameCount : (user - server);
1211                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1212                    }
1213                    // restart playback even if buffer is not completely filled.
1214                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1215                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1216                    // the client
1217                    mCblk->stepUser(frames);
1218                }
1219            }
1220            if (mActive) {
1221                result = mAudioTrack->start();
1222                ALOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1223            }
1224            if (fromStart && result == NO_ERROR) {
1225                mNewPosition = mCblk->server + mUpdatePeriod;
1226            }
1227        }
1228        if (result != NO_ERROR) {
1229            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1230            ALOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1231        }
1232        mRestoreStatus = result;
1233        // signal old cblk condition for other threads waiting for restore completion
1234        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1235        cblk->cv.broadcast();
1236    } else {
1237        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1238            ALOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1239            mLock.unlock();
1240            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1241            if (result == NO_ERROR) {
1242                result = mRestoreStatus;
1243            }
1244            cblk->lock.unlock();
1245            mLock.lock();
1246        } else {
1247            ALOGW("dead IAudioTrack, already restored TID %d", gettid());
1248            result = mRestoreStatus;
1249            cblk->lock.unlock();
1250        }
1251    }
1252    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1253         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1254
1255    if (result == NO_ERROR) {
1256        // from now on we switch to the newly created cblk
1257        cblk = mCblk;
1258    }
1259    cblk->lock.lock();
1260
1261    ALOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1262
1263    return result;
1264}
1265
1266status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1267{
1268
1269    const size_t SIZE = 256;
1270    char buffer[SIZE];
1271    String8 result;
1272
1273    result.append(" AudioTrack::dump\n");
1274    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1275    result.append(buffer);
1276    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1277    result.append(buffer);
1278    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1279    result.append(buffer);
1280    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1281    result.append(buffer);
1282    ::write(fd, result.string(), result.size());
1283    return NO_ERROR;
1284}
1285
1286// =========================================================================
1287
1288AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1289    : Thread(bCanCallJava), mReceiver(receiver)
1290{
1291}
1292
1293bool AudioTrack::AudioTrackThread::threadLoop()
1294{
1295    return mReceiver.processAudioBuffer(this);
1296}
1297
1298status_t AudioTrack::AudioTrackThread::readyToRun()
1299{
1300    return NO_ERROR;
1301}
1302
1303void AudioTrack::AudioTrackThread::onFirstRef()
1304{
1305}
1306
1307// =========================================================================
1308
1309
1310audio_track_cblk_t::audio_track_cblk_t()
1311    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1312    userBase(0), serverBase(0), buffers(NULL), frameCount(0),
1313    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), mVolumeLR(0x10001000),
1314    mSendLevel(0), flags(0)
1315{
1316}
1317
1318uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1319{
1320    uint32_t u = user;
1321
1322    u += frameCount;
1323    // Ensure that user is never ahead of server for AudioRecord
1324    if (flags & CBLK_DIRECTION_MSK) {
1325        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1326        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1327            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1328        }
1329    } else if (u > server) {
1330        ALOGW("stepServer occurred after track reset");
1331        u = server;
1332    }
1333
1334    if (u >= userBase + this->frameCount) {
1335        userBase += this->frameCount;
1336    }
1337
1338    user = u;
1339
1340    // Clear flow control error condition as new data has been written/read to/from buffer.
1341    if (flags & CBLK_UNDERRUN_MSK) {
1342        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1343    }
1344
1345    return u;
1346}
1347
1348bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1349{
1350    if (!tryLock()) {
1351        ALOGW("stepServer() could not lock cblk");
1352        return false;
1353    }
1354
1355    uint32_t s = server;
1356
1357    s += frameCount;
1358    if (flags & CBLK_DIRECTION_MSK) {
1359        // Mark that we have read the first buffer so that next time stepUser() is called
1360        // we switch to normal obtainBuffer() timeout period
1361        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1362            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1363        }
1364        // It is possible that we receive a flush()
1365        // while the mixer is processing a block: in this case,
1366        // stepServer() is called After the flush() has reset u & s and
1367        // we have s > u
1368        if (s > user) {
1369            ALOGW("stepServer occurred after track reset");
1370            s = user;
1371        }
1372    }
1373
1374    if (s >= loopEnd) {
1375        ALOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1376        s = loopStart;
1377        if (--loopCount == 0) {
1378            loopEnd = UINT_MAX;
1379            loopStart = UINT_MAX;
1380        }
1381    }
1382    if (s >= serverBase + this->frameCount) {
1383        serverBase += this->frameCount;
1384    }
1385
1386    server = s;
1387
1388    if (!(flags & CBLK_INVALID_MSK)) {
1389        cv.signal();
1390    }
1391    lock.unlock();
1392    return true;
1393}
1394
1395void* audio_track_cblk_t::buffer(uint32_t offset) const
1396{
1397    return (int8_t *)buffers + (offset - userBase) * frameSize;
1398}
1399
1400uint32_t audio_track_cblk_t::framesAvailable()
1401{
1402    Mutex::Autolock _l(lock);
1403    return framesAvailable_l();
1404}
1405
1406uint32_t audio_track_cblk_t::framesAvailable_l()
1407{
1408    uint32_t u = user;
1409    uint32_t s = server;
1410
1411    if (flags & CBLK_DIRECTION_MSK) {
1412        uint32_t limit = (s < loopStart) ? s : loopStart;
1413        return limit + frameCount - u;
1414    } else {
1415        return frameCount + u - s;
1416    }
1417}
1418
1419uint32_t audio_track_cblk_t::framesReady()
1420{
1421    uint32_t u = user;
1422    uint32_t s = server;
1423
1424    if (flags & CBLK_DIRECTION_MSK) {
1425        if (u < loopEnd) {
1426            return u - s;
1427        } else {
1428            // do not block on mutex shared with client on AudioFlinger side
1429            if (!tryLock()) {
1430                ALOGW("framesReady() could not lock cblk");
1431                return 0;
1432            }
1433            uint32_t frames = UINT_MAX;
1434            if (loopCount >= 0) {
1435                frames = (loopEnd - loopStart)*loopCount + u - s;
1436            }
1437            lock.unlock();
1438            return frames;
1439        }
1440    } else {
1441        return s - u;
1442    }
1443}
1444
1445bool audio_track_cblk_t::tryLock()
1446{
1447    // the code below simulates lock-with-timeout
1448    // we MUST do this to protect the AudioFlinger server
1449    // as this lock is shared with the client.
1450    status_t err;
1451
1452    err = lock.tryLock();
1453    if (err == -EBUSY) { // just wait a bit
1454        usleep(1000);
1455        err = lock.tryLock();
1456    }
1457    if (err != NO_ERROR) {
1458        // probably, the client just died.
1459        return false;
1460    }
1461    return true;
1462}
1463
1464// -------------------------------------------------------------------------
1465
1466}; // namespace android
1467