AudioTrack.cpp revision 9a2aaf927e56a4b4acab23ef16b3f133a9f48a63 
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
46namespace android {
47// ---------------------------------------------------------------------------
48
49// static
50status_t AudioTrack::getMinFrameCount(
51        int* frameCount,
52        int streamType,
53        uint32_t sampleRate)
54{
55    int afSampleRate;
56    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
57        return NO_INIT;
58    }
59    int afFrameCount;
60    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
61        return NO_INIT;
62    }
63    uint32_t afLatency;
64    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
65        return NO_INIT;
66    }
67
68    // Ensure that buffer depth covers at least audio hardware latency
69    uint32_t minBufCount = afLatency / ((1000 * afFrameCount) / afSampleRate);
70    if (minBufCount < 2) minBufCount = 2;
71
72    *frameCount = (sampleRate == 0) ? afFrameCount * minBufCount :
73              afFrameCount * minBufCount * sampleRate / afSampleRate;
74    return NO_ERROR;
75}
76
77// ---------------------------------------------------------------------------
78
79AudioTrack::AudioTrack()
80    : mStatus(NO_INIT),
81      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
82{
83}
84
85AudioTrack::AudioTrack(
86        int streamType,
87        uint32_t sampleRate,
88        int format,
89        int channelMask,
90        int frameCount,
91        uint32_t flags,
92        callback_t cbf,
93        void* user,
94        int notificationFrames,
95        int sessionId)
96    : mStatus(NO_INIT),
97      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
98{
99    mStatus = set(streamType, sampleRate, format, channelMask,
100            frameCount, flags, cbf, user, notificationFrames,
101            0, false, sessionId);
102}
103
104AudioTrack::AudioTrack(
105        int streamType,
106        uint32_t sampleRate,
107        int format,
108        int channelMask,
109        const sp<IMemory>& sharedBuffer,
110        uint32_t flags,
111        callback_t cbf,
112        void* user,
113        int notificationFrames,
114        int sessionId)
115    : mStatus(NO_INIT),
116      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
117{
118    mStatus = set(streamType, sampleRate, format, channelMask,
119            0, flags, cbf, user, notificationFrames,
120            sharedBuffer, false, sessionId);
121}
122
123AudioTrack::~AudioTrack()
124{
125    ALOGV_IF(mSharedBuffer != 0, "Destructor sharedBuffer: %p", mSharedBuffer->pointer());
126
127    if (mStatus == NO_ERROR) {
128        // Make sure that callback function exits in the case where
129        // it is looping on buffer full condition in obtainBuffer().
130        // Otherwise the callback thread will never exit.
131        stop();
132        if (mAudioTrackThread != 0) {
133            mAudioTrackThread->requestExitAndWait();
134            mAudioTrackThread.clear();
135        }
136        mAudioTrack.clear();
137        IPCThreadState::self()->flushCommands();
138        AudioSystem::releaseAudioSessionId(mSessionId);
139    }
140}
141
142status_t AudioTrack::set(
143        int streamType,
144        uint32_t sampleRate,
145        int format,
146        int channelMask,
147        int frameCount,
148        uint32_t flags,
149        callback_t cbf,
150        void* user,
151        int notificationFrames,
152        const sp<IMemory>& sharedBuffer,
153        bool threadCanCallJava,
154        int sessionId)
155{
156
157    ALOGV_IF(sharedBuffer != 0, "sharedBuffer: %p, size: %d", sharedBuffer->pointer(), sharedBuffer->size());
158
159    AutoMutex lock(mLock);
160    if (mAudioTrack != 0) {
161        LOGE("Track already in use");
162        return INVALID_OPERATION;
163    }
164
165    int afSampleRate;
166    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
167        return NO_INIT;
168    }
169    uint32_t afLatency;
170    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
171        return NO_INIT;
172    }
173
174    // handle default values first.
175    if (streamType == AUDIO_STREAM_DEFAULT) {
176        streamType = AUDIO_STREAM_MUSIC;
177    }
178    if (sampleRate == 0) {
179        sampleRate = afSampleRate;
180    }
181    // these below should probably come from the audioFlinger too...
182    if (format == 0) {
183        format = AUDIO_FORMAT_PCM_16_BIT;
184    }
185    if (channelMask == 0) {
186        channelMask = AUDIO_CHANNEL_OUT_STEREO;
187    }
188
189    // validate parameters
190    if (!audio_is_valid_format(format)) {
191        LOGE("Invalid format");
192        return BAD_VALUE;
193    }
194
195    // force direct flag if format is not linear PCM
196    if (!audio_is_linear_pcm(format)) {
197        flags |= AUDIO_POLICY_OUTPUT_FLAG_DIRECT;
198    }
199
200    if (!audio_is_output_channel(channelMask)) {
201        LOGE("Invalid channel mask");
202        return BAD_VALUE;
203    }
204    uint32_t channelCount = popcount(channelMask);
205
206    audio_io_handle_t output = AudioSystem::getOutput(
207                                    (audio_stream_type_t)streamType,
208                                    sampleRate,format, channelMask,
209                                    (audio_policy_output_flags_t)flags);
210
211    if (output == 0) {
212        LOGE("Could not get audio output for stream type %d", streamType);
213        return BAD_VALUE;
214    }
215
216    mVolume[LEFT] = 1.0f;
217    mVolume[RIGHT] = 1.0f;
218    mSendLevel = 0;
219    mFrameCount = frameCount;
220    mNotificationFramesReq = notificationFrames;
221    mSessionId = sessionId;
222    mAuxEffectId = 0;
223
224    // create the IAudioTrack
225    status_t status = createTrack_l(streamType,
226                                  sampleRate,
227                                  (uint32_t)format,
228                                  (uint32_t)channelMask,
229                                  frameCount,
230                                  flags,
231                                  sharedBuffer,
232                                  output,
233                                  true);
234
235    if (status != NO_ERROR) {
236        return status;
237    }
238
239    if (cbf != 0) {
240        mAudioTrackThread = new AudioTrackThread(*this, threadCanCallJava);
241        if (mAudioTrackThread == 0) {
242          LOGE("Could not create callback thread");
243          return NO_INIT;
244        }
245    }
246
247    mStatus = NO_ERROR;
248
249    mStreamType = streamType;
250    mFormat = (uint32_t)format;
251    mChannelMask = (uint32_t)channelMask;
252    mChannelCount = channelCount;
253    mSharedBuffer = sharedBuffer;
254    mMuted = false;
255    mActive = false;
256    mCbf = cbf;
257    mUserData = user;
258    mLoopCount = 0;
259    mMarkerPosition = 0;
260    mMarkerReached = false;
261    mNewPosition = 0;
262    mUpdatePeriod = 0;
263    mFlushed = false;
264    mFlags = flags;
265    AudioSystem::acquireAudioSessionId(mSessionId);
266    mRestoreStatus = NO_ERROR;
267    return NO_ERROR;
268}
269
270status_t AudioTrack::initCheck() const
271{
272    return mStatus;
273}
274
275// -------------------------------------------------------------------------
276
277uint32_t AudioTrack::latency() const
278{
279    return mLatency;
280}
281
282int AudioTrack::streamType() const
283{
284    return mStreamType;
285}
286
287int AudioTrack::format() const
288{
289    return mFormat;
290}
291
292int AudioTrack::channelCount() const
293{
294    return mChannelCount;
295}
296
297uint32_t AudioTrack::frameCount() const
298{
299    return mCblk->frameCount;
300}
301
302int AudioTrack::frameSize() const
303{
304    if (audio_is_linear_pcm(mFormat)) {
305        return channelCount()*audio_bytes_per_sample(mFormat);
306    } else {
307        return sizeof(uint8_t);
308    }
309}
310
311sp<IMemory>& AudioTrack::sharedBuffer()
312{
313    return mSharedBuffer;
314}
315
316// -------------------------------------------------------------------------
317
318void AudioTrack::start()
319{
320    sp<AudioTrackThread> t = mAudioTrackThread;
321    status_t status = NO_ERROR;
322
323    ALOGV("start %p", this);
324    if (t != 0) {
325        if (t->exitPending()) {
326            if (t->requestExitAndWait() == WOULD_BLOCK) {
327                LOGE("AudioTrack::start called from thread");
328                return;
329            }
330        }
331        t->mLock.lock();
332     }
333
334    AutoMutex lock(mLock);
335    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
336    // while we are accessing the cblk
337    sp <IAudioTrack> audioTrack = mAudioTrack;
338    sp <IMemory> iMem = mCblkMemory;
339    audio_track_cblk_t* cblk = mCblk;
340
341    if (!mActive) {
342        mFlushed = false;
343        mActive = true;
344        mNewPosition = cblk->server + mUpdatePeriod;
345        cblk->lock.lock();
346        cblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
347        cblk->waitTimeMs = 0;
348        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
349        if (t != 0) {
350            t->run("AudioTrackThread", ANDROID_PRIORITY_AUDIO);
351        } else {
352            mPreviousPriority = getpriority(PRIO_PROCESS, 0);
353            mPreviousSchedulingGroup = androidGetThreadSchedulingGroup(0);
354            androidSetThreadPriority(0, ANDROID_PRIORITY_AUDIO);
355        }
356
357        ALOGV("start %p before lock cblk %p", this, mCblk);
358        if (!(cblk->flags & CBLK_INVALID_MSK)) {
359            cblk->lock.unlock();
360            status = mAudioTrack->start();
361            cblk->lock.lock();
362            if (status == DEAD_OBJECT) {
363                android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
364            }
365        }
366        if (cblk->flags & CBLK_INVALID_MSK) {
367            status = restoreTrack_l(cblk, true);
368        }
369        cblk->lock.unlock();
370        if (status != NO_ERROR) {
371            ALOGV("start() failed");
372            mActive = false;
373            if (t != 0) {
374                t->requestExit();
375            } else {
376                setpriority(PRIO_PROCESS, 0, mPreviousPriority);
377                androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
378            }
379        }
380    }
381
382    if (t != 0) {
383        t->mLock.unlock();
384    }
385}
386
387void AudioTrack::stop()
388{
389    sp<AudioTrackThread> t = mAudioTrackThread;
390
391    ALOGV("stop %p", this);
392    if (t != 0) {
393        t->mLock.lock();
394    }
395
396    AutoMutex lock(mLock);
397    if (mActive) {
398        mActive = false;
399        mCblk->cv.signal();
400        mAudioTrack->stop();
401        // Cancel loops (If we are in the middle of a loop, playback
402        // would not stop until loopCount reaches 0).
403        setLoop_l(0, 0, 0);
404        // the playback head position will reset to 0, so if a marker is set, we need
405        // to activate it again
406        mMarkerReached = false;
407        // Force flush if a shared buffer is used otherwise audioflinger
408        // will not stop before end of buffer is reached.
409        if (mSharedBuffer != 0) {
410            flush_l();
411        }
412        if (t != 0) {
413            t->requestExit();
414        } else {
415            setpriority(PRIO_PROCESS, 0, mPreviousPriority);
416            androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
417        }
418    }
419
420    if (t != 0) {
421        t->mLock.unlock();
422    }
423}
424
425bool AudioTrack::stopped() const
426{
427    AutoMutex lock(mLock);
428    return stopped_l();
429}
430
431void AudioTrack::flush()
432{
433    AutoMutex lock(mLock);
434    flush_l();
435}
436
437// must be called with mLock held
438void AudioTrack::flush_l()
439{
440    ALOGV("flush");
441
442    // clear playback marker and periodic update counter
443    mMarkerPosition = 0;
444    mMarkerReached = false;
445    mUpdatePeriod = 0;
446
447    if (!mActive) {
448        mFlushed = true;
449        mAudioTrack->flush();
450        // Release AudioTrack callback thread in case it was waiting for new buffers
451        // in AudioTrack::obtainBuffer()
452        mCblk->cv.signal();
453    }
454}
455
456void AudioTrack::pause()
457{
458    ALOGV("pause");
459    AutoMutex lock(mLock);
460    if (mActive) {
461        mActive = false;
462        mAudioTrack->pause();
463    }
464}
465
466void AudioTrack::mute(bool e)
467{
468    mAudioTrack->mute(e);
469    mMuted = e;
470}
471
472bool AudioTrack::muted() const
473{
474    return mMuted;
475}
476
477status_t AudioTrack::setVolume(float left, float right)
478{
479    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
480        return BAD_VALUE;
481    }
482
483    AutoMutex lock(mLock);
484    mVolume[LEFT] = left;
485    mVolume[RIGHT] = right;
486
487    // write must be atomic
488    mCblk->volumeLR = (uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000);
489
490    return NO_ERROR;
491}
492
493void AudioTrack::getVolume(float* left, float* right)
494{
495    if (left != NULL) {
496        *left  = mVolume[LEFT];
497    }
498    if (right != NULL) {
499        *right = mVolume[RIGHT];
500    }
501}
502
503status_t AudioTrack::setAuxEffectSendLevel(float level)
504{
505    ALOGV("setAuxEffectSendLevel(%f)", level);
506    if (level > 1.0f) {
507        return BAD_VALUE;
508    }
509    AutoMutex lock(mLock);
510
511    mSendLevel = level;
512
513    mCblk->sendLevel = uint16_t(level * 0x1000);
514
515    return NO_ERROR;
516}
517
518void AudioTrack::getAuxEffectSendLevel(float* level)
519{
520    if (level != NULL) {
521        *level  = mSendLevel;
522    }
523}
524
525status_t AudioTrack::setSampleRate(int rate)
526{
527    int afSamplingRate;
528
529    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
530        return NO_INIT;
531    }
532    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
533    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
534
535    AutoMutex lock(mLock);
536    mCblk->sampleRate = rate;
537    return NO_ERROR;
538}
539
540uint32_t AudioTrack::getSampleRate()
541{
542    AutoMutex lock(mLock);
543    return mCblk->sampleRate;
544}
545
546status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
547{
548    AutoMutex lock(mLock);
549    return setLoop_l(loopStart, loopEnd, loopCount);
550}
551
552// must be called with mLock held
553status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
554{
555    audio_track_cblk_t* cblk = mCblk;
556
557    Mutex::Autolock _l(cblk->lock);
558
559    if (loopCount == 0) {
560        cblk->loopStart = UINT_MAX;
561        cblk->loopEnd = UINT_MAX;
562        cblk->loopCount = 0;
563        mLoopCount = 0;
564        return NO_ERROR;
565    }
566
567    if (loopStart >= loopEnd ||
568        loopEnd - loopStart > cblk->frameCount ||
569        cblk->server > loopStart) {
570        LOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
571        return BAD_VALUE;
572    }
573
574    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
575        LOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
576            loopStart, loopEnd, cblk->frameCount);
577        return BAD_VALUE;
578    }
579
580    cblk->loopStart = loopStart;
581    cblk->loopEnd = loopEnd;
582    cblk->loopCount = loopCount;
583    mLoopCount = loopCount;
584
585    return NO_ERROR;
586}
587
588status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount)
589{
590    AutoMutex lock(mLock);
591    if (loopStart != 0) {
592        *loopStart = mCblk->loopStart;
593    }
594    if (loopEnd != 0) {
595        *loopEnd = mCblk->loopEnd;
596    }
597    if (loopCount != 0) {
598        if (mCblk->loopCount < 0) {
599            *loopCount = -1;
600        } else {
601            *loopCount = mCblk->loopCount;
602        }
603    }
604
605    return NO_ERROR;
606}
607
608status_t AudioTrack::setMarkerPosition(uint32_t marker)
609{
610    if (mCbf == 0) return INVALID_OPERATION;
611
612    mMarkerPosition = marker;
613    mMarkerReached = false;
614
615    return NO_ERROR;
616}
617
618status_t AudioTrack::getMarkerPosition(uint32_t *marker)
619{
620    if (marker == 0) return BAD_VALUE;
621
622    *marker = mMarkerPosition;
623
624    return NO_ERROR;
625}
626
627status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
628{
629    if (mCbf == 0) return INVALID_OPERATION;
630
631    uint32_t curPosition;
632    getPosition(&curPosition);
633    mNewPosition = curPosition + updatePeriod;
634    mUpdatePeriod = updatePeriod;
635
636    return NO_ERROR;
637}
638
639status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod)
640{
641    if (updatePeriod == 0) return BAD_VALUE;
642
643    *updatePeriod = mUpdatePeriod;
644
645    return NO_ERROR;
646}
647
648status_t AudioTrack::setPosition(uint32_t position)
649{
650    AutoMutex lock(mLock);
651
652    if (!stopped_l()) return INVALID_OPERATION;
653
654    Mutex::Autolock _l(mCblk->lock);
655
656    if (position > mCblk->user) return BAD_VALUE;
657
658    mCblk->server = position;
659    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
660
661    return NO_ERROR;
662}
663
664status_t AudioTrack::getPosition(uint32_t *position)
665{
666    if (position == 0) return BAD_VALUE;
667    AutoMutex lock(mLock);
668    *position = mFlushed ? 0 : mCblk->server;
669
670    return NO_ERROR;
671}
672
673status_t AudioTrack::reload()
674{
675    AutoMutex lock(mLock);
676
677    if (!stopped_l()) return INVALID_OPERATION;
678
679    flush_l();
680
681    mCblk->stepUser(mCblk->frameCount);
682
683    return NO_ERROR;
684}
685
686audio_io_handle_t AudioTrack::getOutput()
687{
688    AutoMutex lock(mLock);
689    return getOutput_l();
690}
691
692// must be called with mLock held
693audio_io_handle_t AudioTrack::getOutput_l()
694{
695    return AudioSystem::getOutput((audio_stream_type_t)mStreamType,
696            mCblk->sampleRate, mFormat, mChannelMask, (audio_policy_output_flags_t)mFlags);
697}
698
699int AudioTrack::getSessionId()
700{
701    return mSessionId;
702}
703
704status_t AudioTrack::attachAuxEffect(int effectId)
705{
706    ALOGV("attachAuxEffect(%d)", effectId);
707    status_t status = mAudioTrack->attachAuxEffect(effectId);
708    if (status == NO_ERROR) {
709        mAuxEffectId = effectId;
710    }
711    return status;
712}
713
714// -------------------------------------------------------------------------
715
716// must be called with mLock held
717status_t AudioTrack::createTrack_l(
718        int streamType,
719        uint32_t sampleRate,
720        uint32_t format,
721        uint32_t channelMask,
722        int frameCount,
723        uint32_t flags,
724        const sp<IMemory>& sharedBuffer,
725        audio_io_handle_t output,
726        bool enforceFrameCount)
727{
728    status_t status;
729    const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
730    if (audioFlinger == 0) {
731       LOGE("Could not get audioflinger");
732       return NO_INIT;
733    }
734
735    int afSampleRate;
736    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
737        return NO_INIT;
738    }
739    int afFrameCount;
740    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
741        return NO_INIT;
742    }
743    uint32_t afLatency;
744    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
745        return NO_INIT;
746    }
747
748    mNotificationFramesAct = mNotificationFramesReq;
749    if (!audio_is_linear_pcm(format)) {
750        if (sharedBuffer != 0) {
751            frameCount = sharedBuffer->size();
752        }
753    } else {
754        // Ensure that buffer depth covers at least audio hardware latency
755        uint32_t minBufCount = afLatency / ((1000 * afFrameCount)/afSampleRate);
756        if (minBufCount < 2) minBufCount = 2;
757
758        int minFrameCount = (afFrameCount*sampleRate*minBufCount)/afSampleRate;
759
760        if (sharedBuffer == 0) {
761            if (frameCount == 0) {
762                frameCount = minFrameCount;
763            }
764            if (mNotificationFramesAct == 0) {
765                mNotificationFramesAct = frameCount/2;
766            }
767            // Make sure that application is notified with sufficient margin
768            // before underrun
769            if (mNotificationFramesAct > (uint32_t)frameCount/2) {
770                mNotificationFramesAct = frameCount/2;
771            }
772            if (frameCount < minFrameCount) {
773                if (enforceFrameCount) {
774                    LOGE("Invalid buffer size: minFrameCount %d, frameCount %d", minFrameCount, frameCount);
775                    return BAD_VALUE;
776                } else {
777                    frameCount = minFrameCount;
778                }
779            }
780        } else {
781            // Ensure that buffer alignment matches channelcount
782            int channelCount = popcount(channelMask);
783            if (((uint32_t)sharedBuffer->pointer() & (channelCount | 1)) != 0) {
784                LOGE("Invalid buffer alignement: address %p, channelCount %d", sharedBuffer->pointer(), channelCount);
785                return BAD_VALUE;
786            }
787            frameCount = sharedBuffer->size()/channelCount/sizeof(int16_t);
788        }
789    }
790
791    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
792                                                      streamType,
793                                                      sampleRate,
794                                                      format,
795                                                      channelMask,
796                                                      frameCount,
797                                                      ((uint16_t)flags) << 16,
798                                                      sharedBuffer,
799                                                      output,
800                                                      &mSessionId,
801                                                      &status);
802
803    if (track == 0) {
804        LOGE("AudioFlinger could not create track, status: %d", status);
805        return status;
806    }
807    sp<IMemory> cblk = track->getCblk();
808    if (cblk == 0) {
809        LOGE("Could not get control block");
810        return NO_INIT;
811    }
812    mAudioTrack = track;
813    mCblkMemory = cblk;
814    mCblk = static_cast<audio_track_cblk_t*>(cblk->pointer());
815    android_atomic_or(CBLK_DIRECTION_OUT, &mCblk->flags);
816    if (sharedBuffer == 0) {
817        mCblk->buffers = (char*)mCblk + sizeof(audio_track_cblk_t);
818    } else {
819        mCblk->buffers = sharedBuffer->pointer();
820         // Force buffer full condition as data is already present in shared memory
821        mCblk->stepUser(mCblk->frameCount);
822    }
823
824    mCblk->volumeLR = (uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000);
825    mCblk->sendLevel = uint16_t(mSendLevel * 0x1000);
826    mAudioTrack->attachAuxEffect(mAuxEffectId);
827    mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
828    mCblk->waitTimeMs = 0;
829    mRemainingFrames = mNotificationFramesAct;
830    mLatency = afLatency + (1000*mCblk->frameCount) / sampleRate;
831    return NO_ERROR;
832}
833
834status_t AudioTrack::obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
835{
836    AutoMutex lock(mLock);
837    bool active;
838    status_t result = NO_ERROR;
839    audio_track_cblk_t* cblk = mCblk;
840    uint32_t framesReq = audioBuffer->frameCount;
841    uint32_t waitTimeMs = (waitCount < 0) ? cblk->bufferTimeoutMs : WAIT_PERIOD_MS;
842
843    audioBuffer->frameCount  = 0;
844    audioBuffer->size = 0;
845
846    uint32_t framesAvail = cblk->framesAvailable();
847
848    cblk->lock.lock();
849    if (cblk->flags & CBLK_INVALID_MSK) {
850        goto create_new_track;
851    }
852    cblk->lock.unlock();
853
854    if (framesAvail == 0) {
855        cblk->lock.lock();
856        goto start_loop_here;
857        while (framesAvail == 0) {
858            active = mActive;
859            if (CC_UNLIKELY(!active)) {
860                ALOGV("Not active and NO_MORE_BUFFERS");
861                cblk->lock.unlock();
862                return NO_MORE_BUFFERS;
863            }
864            if (CC_UNLIKELY(!waitCount)) {
865                cblk->lock.unlock();
866                return WOULD_BLOCK;
867            }
868            if (!(cblk->flags & CBLK_INVALID_MSK)) {
869                mLock.unlock();
870                result = cblk->cv.waitRelative(cblk->lock, milliseconds(waitTimeMs));
871                cblk->lock.unlock();
872                mLock.lock();
873                if (!mActive) {
874                    return status_t(STOPPED);
875                }
876                cblk->lock.lock();
877            }
878
879            if (cblk->flags & CBLK_INVALID_MSK) {
880                goto create_new_track;
881            }
882            if (CC_UNLIKELY(result != NO_ERROR)) {
883                cblk->waitTimeMs += waitTimeMs;
884                if (cblk->waitTimeMs >= cblk->bufferTimeoutMs) {
885                    // timing out when a loop has been set and we have already written upto loop end
886                    // is a normal condition: no need to wake AudioFlinger up.
887                    if (cblk->user < cblk->loopEnd) {
888                        LOGW(   "obtainBuffer timed out (is the CPU pegged?) %p "
889                                "user=%08x, server=%08x", this, cblk->user, cblk->server);
890                        //unlock cblk mutex before calling mAudioTrack->start() (see issue #1617140)
891                        cblk->lock.unlock();
892                        result = mAudioTrack->start();
893                        cblk->lock.lock();
894                        if (result == DEAD_OBJECT) {
895                            android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
896create_new_track:
897                            result = restoreTrack_l(cblk, false);
898                        }
899                        if (result != NO_ERROR) {
900                            LOGW("obtainBuffer create Track error %d", result);
901                            cblk->lock.unlock();
902                            return result;
903                        }
904                    }
905                    cblk->waitTimeMs = 0;
906                }
907
908                if (--waitCount == 0) {
909                    cblk->lock.unlock();
910                    return TIMED_OUT;
911                }
912            }
913            // read the server count again
914        start_loop_here:
915            framesAvail = cblk->framesAvailable_l();
916        }
917        cblk->lock.unlock();
918    }
919
920    // restart track if it was disabled by audioflinger due to previous underrun
921    if (mActive && (cblk->flags & CBLK_DISABLED_MSK)) {
922        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
923        LOGW("obtainBuffer() track %p disabled, restarting", this);
924        mAudioTrack->start();
925    }
926
927    cblk->waitTimeMs = 0;
928
929    if (framesReq > framesAvail) {
930        framesReq = framesAvail;
931    }
932
933    uint32_t u = cblk->user;
934    uint32_t bufferEnd = cblk->userBase + cblk->frameCount;
935
936    if (u + framesReq > bufferEnd) {
937        framesReq = bufferEnd - u;
938    }
939
940    audioBuffer->flags = mMuted ? Buffer::MUTE : 0;
941    audioBuffer->channelCount = mChannelCount;
942    audioBuffer->frameCount = framesReq;
943    audioBuffer->size = framesReq * cblk->frameSize;
944    if (audio_is_linear_pcm(mFormat)) {
945        audioBuffer->format = AUDIO_FORMAT_PCM_16_BIT;
946    } else {
947        audioBuffer->format = mFormat;
948    }
949    audioBuffer->raw = (int8_t *)cblk->buffer(u);
950    active = mActive;
951    return active ? status_t(NO_ERROR) : status_t(STOPPED);
952}
953
954void AudioTrack::releaseBuffer(Buffer* audioBuffer)
955{
956    AutoMutex lock(mLock);
957    mCblk->stepUser(audioBuffer->frameCount);
958}
959
960// -------------------------------------------------------------------------
961
962ssize_t AudioTrack::write(const void* buffer, size_t userSize)
963{
964
965    if (mSharedBuffer != 0) return INVALID_OPERATION;
966
967    if (ssize_t(userSize) < 0) {
968        // sanity-check. user is most-likely passing an error code.
969        LOGE("AudioTrack::write(buffer=%p, size=%u (%d)",
970                buffer, userSize, userSize);
971        return BAD_VALUE;
972    }
973
974    ALOGV("write %p: %d bytes, mActive=%d", this, userSize, mActive);
975
976    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
977    // while we are accessing the cblk
978    mLock.lock();
979    sp <IAudioTrack> audioTrack = mAudioTrack;
980    sp <IMemory> iMem = mCblkMemory;
981    mLock.unlock();
982
983    ssize_t written = 0;
984    const int8_t *src = (const int8_t *)buffer;
985    Buffer audioBuffer;
986    size_t frameSz = (size_t)frameSize();
987
988    do {
989        audioBuffer.frameCount = userSize/frameSz;
990
991        // Calling obtainBuffer() with a negative wait count causes
992        // an (almost) infinite wait time.
993        status_t err = obtainBuffer(&audioBuffer, -1);
994        if (err < 0) {
995            // out of buffers, return #bytes written
996            if (err == status_t(NO_MORE_BUFFERS))
997                break;
998            return ssize_t(err);
999        }
1000
1001        size_t toWrite;
1002
1003        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1004            // Divide capacity by 2 to take expansion into account
1005            toWrite = audioBuffer.size>>1;
1006            // 8 to 16 bit conversion
1007            int count = toWrite;
1008            int16_t *dst = (int16_t *)(audioBuffer.i8);
1009            while(count--) {
1010                *dst++ = (int16_t)(*src++^0x80) << 8;
1011            }
1012        } else {
1013            toWrite = audioBuffer.size;
1014            memcpy(audioBuffer.i8, src, toWrite);
1015            src += toWrite;
1016        }
1017        userSize -= toWrite;
1018        written += toWrite;
1019
1020        releaseBuffer(&audioBuffer);
1021    } while (userSize >= frameSz);
1022
1023    return written;
1024}
1025
1026// -------------------------------------------------------------------------
1027
1028bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1029{
1030    Buffer audioBuffer;
1031    uint32_t frames;
1032    size_t writtenSize;
1033
1034    mLock.lock();
1035    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1036    // while we are accessing the cblk
1037    sp <IAudioTrack> audioTrack = mAudioTrack;
1038    sp <IMemory> iMem = mCblkMemory;
1039    audio_track_cblk_t* cblk = mCblk;
1040    bool active = mActive;
1041    mLock.unlock();
1042
1043    // Manage underrun callback
1044    if (active && (cblk->framesAvailable() == cblk->frameCount)) {
1045        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1046        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1047            mCbf(EVENT_UNDERRUN, mUserData, 0);
1048            if (cblk->server == cblk->frameCount) {
1049                mCbf(EVENT_BUFFER_END, mUserData, 0);
1050            }
1051            if (mSharedBuffer != 0) return false;
1052        }
1053    }
1054
1055    // Manage loop end callback
1056    while (mLoopCount > cblk->loopCount) {
1057        int loopCount = -1;
1058        mLoopCount--;
1059        if (mLoopCount >= 0) loopCount = mLoopCount;
1060
1061        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1062    }
1063
1064    // Manage marker callback
1065    if (!mMarkerReached && (mMarkerPosition > 0)) {
1066        if (cblk->server >= mMarkerPosition) {
1067            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1068            mMarkerReached = true;
1069        }
1070    }
1071
1072    // Manage new position callback
1073    if (mUpdatePeriod > 0) {
1074        while (cblk->server >= mNewPosition) {
1075            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1076            mNewPosition += mUpdatePeriod;
1077        }
1078    }
1079
1080    // If Shared buffer is used, no data is requested from client.
1081    if (mSharedBuffer != 0) {
1082        frames = 0;
1083    } else {
1084        frames = mRemainingFrames;
1085    }
1086
1087    int32_t waitCount = -1;
1088    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1089        waitCount = 1;
1090    }
1091
1092    do {
1093
1094        audioBuffer.frameCount = frames;
1095
1096        // Calling obtainBuffer() with a wait count of 1
1097        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1098        // stuck here not being able to handle timed events (position, markers, loops).
1099        status_t err = obtainBuffer(&audioBuffer, waitCount);
1100        if (err < NO_ERROR) {
1101            if (err != TIMED_OUT) {
1102                LOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1103                return false;
1104            }
1105            break;
1106        }
1107        if (err == status_t(STOPPED)) return false;
1108
1109        // Divide buffer size by 2 to take into account the expansion
1110        // due to 8 to 16 bit conversion: the callback must fill only half
1111        // of the destination buffer
1112        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1113            audioBuffer.size >>= 1;
1114        }
1115
1116        size_t reqSize = audioBuffer.size;
1117        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1118        writtenSize = audioBuffer.size;
1119
1120        // Sanity check on returned size
1121        if (ssize_t(writtenSize) <= 0) {
1122            // The callback is done filling buffers
1123            // Keep this thread going to handle timed events and
1124            // still try to get more data in intervals of WAIT_PERIOD_MS
1125            // but don't just loop and block the CPU, so wait
1126            usleep(WAIT_PERIOD_MS*1000);
1127            break;
1128        }
1129        if (writtenSize > reqSize) writtenSize = reqSize;
1130
1131        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1132            // 8 to 16 bit conversion
1133            const int8_t *src = audioBuffer.i8 + writtenSize-1;
1134            int count = writtenSize;
1135            int16_t *dst = audioBuffer.i16 + writtenSize-1;
1136            while(count--) {
1137                *dst-- = (int16_t)(*src--^0x80) << 8;
1138            }
1139            writtenSize <<= 1;
1140        }
1141
1142        audioBuffer.size = writtenSize;
1143        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1144        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sampel size of
1145        // 16 bit.
1146        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1147
1148        frames -= audioBuffer.frameCount;
1149
1150        releaseBuffer(&audioBuffer);
1151    }
1152    while (frames);
1153
1154    if (frames == 0) {
1155        mRemainingFrames = mNotificationFramesAct;
1156    } else {
1157        mRemainingFrames = frames;
1158    }
1159    return true;
1160}
1161
1162// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1163// the IAudioTrack and IMemory in case they are recreated here.
1164// If the IAudioTrack is successfully restored, the cblk pointer is updated
1165status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1166{
1167    status_t result;
1168
1169    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1170        LOGW("dead IAudioTrack, creating a new one from %s TID %d",
1171             fromStart ? "start()" : "obtainBuffer()", gettid());
1172
1173        // signal old cblk condition so that other threads waiting for available buffers stop
1174        // waiting now
1175        cblk->cv.broadcast();
1176        cblk->lock.unlock();
1177
1178        // refresh the audio configuration cache in this process to make sure we get new
1179        // output parameters in getOutput_l() and createTrack_l()
1180        AudioSystem::clearAudioConfigCache();
1181
1182        // if the new IAudioTrack is created, createTrack_l() will modify the
1183        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1184        // It will also delete the strong references on previous IAudioTrack and IMemory
1185        result = createTrack_l(mStreamType,
1186                               cblk->sampleRate,
1187                               mFormat,
1188                               mChannelMask,
1189                               mFrameCount,
1190                               mFlags,
1191                               mSharedBuffer,
1192                               getOutput_l(),
1193                               false);
1194
1195        if (result == NO_ERROR) {
1196            uint32_t user = cblk->user;
1197            uint32_t server = cblk->server;
1198            // restore write index and set other indexes to reflect empty buffer status
1199            mCblk->user = user;
1200            mCblk->server = user;
1201            mCblk->userBase = user;
1202            mCblk->serverBase = user;
1203            // restore loop: this is not guaranteed to succeed if new frame count is not
1204            // compatible with loop length
1205            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1206            if (!fromStart) {
1207                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1208                // Make sure that a client relying on callback events indicating underrun or
1209                // the actual amount of audio frames played (e.g SoundPool) receives them.
1210                if (mSharedBuffer == 0) {
1211                    uint32_t frames = 0;
1212                    if (user > server) {
1213                        frames = ((user - server) > mCblk->frameCount) ?
1214                                mCblk->frameCount : (user - server);
1215                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1216                    }
1217                    // restart playback even if buffer is not completely filled.
1218                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1219                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1220                    // the client
1221                    mCblk->stepUser(frames);
1222                }
1223            }
1224            if (mActive) {
1225                result = mAudioTrack->start();
1226                LOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1227            }
1228            if (fromStart && result == NO_ERROR) {
1229                mNewPosition = mCblk->server + mUpdatePeriod;
1230            }
1231        }
1232        if (result != NO_ERROR) {
1233            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1234            LOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1235        }
1236        mRestoreStatus = result;
1237        // signal old cblk condition for other threads waiting for restore completion
1238        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1239        cblk->cv.broadcast();
1240    } else {
1241        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1242            LOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1243            mLock.unlock();
1244            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1245            if (result == NO_ERROR) {
1246                result = mRestoreStatus;
1247            }
1248            cblk->lock.unlock();
1249            mLock.lock();
1250        } else {
1251            LOGW("dead IAudioTrack, already restored TID %d", gettid());
1252            result = mRestoreStatus;
1253            cblk->lock.unlock();
1254        }
1255    }
1256    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1257         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1258
1259    if (result == NO_ERROR) {
1260        // from now on we switch to the newly created cblk
1261        cblk = mCblk;
1262    }
1263    cblk->lock.lock();
1264
1265    LOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1266
1267    return result;
1268}
1269
1270status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1271{
1272
1273    const size_t SIZE = 256;
1274    char buffer[SIZE];
1275    String8 result;
1276
1277    result.append(" AudioTrack::dump\n");
1278    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1279    result.append(buffer);
1280    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1281    result.append(buffer);
1282    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1283    result.append(buffer);
1284    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1285    result.append(buffer);
1286    ::write(fd, result.string(), result.size());
1287    return NO_ERROR;
1288}
1289
1290// =========================================================================
1291
1292AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1293    : Thread(bCanCallJava), mReceiver(receiver)
1294{
1295}
1296
1297bool AudioTrack::AudioTrackThread::threadLoop()
1298{
1299    return mReceiver.processAudioBuffer(this);
1300}
1301
1302status_t AudioTrack::AudioTrackThread::readyToRun()
1303{
1304    return NO_ERROR;
1305}
1306
1307void AudioTrack::AudioTrackThread::onFirstRef()
1308{
1309}
1310
1311// =========================================================================
1312
1313
1314audio_track_cblk_t::audio_track_cblk_t()
1315    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1316    userBase(0), serverBase(0), buffers(0), frameCount(0),
1317    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), volumeLR(0),
1318    sendLevel(0), flags(0)
1319{
1320}
1321
1322uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1323{
1324    uint32_t u = user;
1325
1326    u += frameCount;
1327    // Ensure that user is never ahead of server for AudioRecord
1328    if (flags & CBLK_DIRECTION_MSK) {
1329        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1330        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1331            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1332        }
1333    } else if (u > server) {
1334        LOGW("stepServer occurred after track reset");
1335        u = server;
1336    }
1337
1338    if (u >= userBase + this->frameCount) {
1339        userBase += this->frameCount;
1340    }
1341
1342    user = u;
1343
1344    // Clear flow control error condition as new data has been written/read to/from buffer.
1345    if (flags & CBLK_UNDERRUN_MSK) {
1346        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1347    }
1348
1349    return u;
1350}
1351
1352bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1353{
1354    if (!tryLock()) {
1355        LOGW("stepServer() could not lock cblk");
1356        return false;
1357    }
1358
1359    uint32_t s = server;
1360
1361    s += frameCount;
1362    if (flags & CBLK_DIRECTION_MSK) {
1363        // Mark that we have read the first buffer so that next time stepUser() is called
1364        // we switch to normal obtainBuffer() timeout period
1365        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1366            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1367        }
1368        // It is possible that we receive a flush()
1369        // while the mixer is processing a block: in this case,
1370        // stepServer() is called After the flush() has reset u & s and
1371        // we have s > u
1372        if (s > user) {
1373            LOGW("stepServer occurred after track reset");
1374            s = user;
1375        }
1376    }
1377
1378    if (s >= loopEnd) {
1379        LOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1380        s = loopStart;
1381        if (--loopCount == 0) {
1382            loopEnd = UINT_MAX;
1383            loopStart = UINT_MAX;
1384        }
1385    }
1386    if (s >= serverBase + this->frameCount) {
1387        serverBase += this->frameCount;
1388    }
1389
1390    server = s;
1391
1392    if (!(flags & CBLK_INVALID_MSK)) {
1393        cv.signal();
1394    }
1395    lock.unlock();
1396    return true;
1397}
1398
1399void* audio_track_cblk_t::buffer(uint32_t offset) const
1400{
1401    return (int8_t *)buffers + (offset - userBase) * frameSize;
1402}
1403
1404uint32_t audio_track_cblk_t::framesAvailable()
1405{
1406    Mutex::Autolock _l(lock);
1407    return framesAvailable_l();
1408}
1409
1410uint32_t audio_track_cblk_t::framesAvailable_l()
1411{
1412    uint32_t u = user;
1413    uint32_t s = server;
1414
1415    if (flags & CBLK_DIRECTION_MSK) {
1416        uint32_t limit = (s < loopStart) ? s : loopStart;
1417        return limit + frameCount - u;
1418    } else {
1419        return frameCount + u - s;
1420    }
1421}
1422
1423uint32_t audio_track_cblk_t::framesReady()
1424{
1425    uint32_t u = user;
1426    uint32_t s = server;
1427
1428    if (flags & CBLK_DIRECTION_MSK) {
1429        if (u < loopEnd) {
1430            return u - s;
1431        } else {
1432            // do not block on mutex shared with client on AudioFlinger side
1433            if (!tryLock()) {
1434                LOGW("framesReady() could not lock cblk");
1435                return 0;
1436            }
1437            uint32_t frames = UINT_MAX;
1438            if (loopCount >= 0) {
1439                frames = (loopEnd - loopStart)*loopCount + u - s;
1440            }
1441            lock.unlock();
1442            return frames;
1443        }
1444    } else {
1445        return s - u;
1446    }
1447}
1448
1449bool audio_track_cblk_t::tryLock()
1450{
1451    // the code below simulates lock-with-timeout
1452    // we MUST do this to protect the AudioFlinger server
1453    // as this lock is shared with the client.
1454    status_t err;
1455
1456    err = lock.tryLock();
1457    if (err == -EBUSY) { // just wait a bit
1458        usleep(1000);
1459        err = lock.tryLock();
1460    }
1461    if (err != NO_ERROR) {
1462        // probably, the client just died.
1463        return false;
1464    }
1465    return true;
1466}
1467
1468// -------------------------------------------------------------------------
1469
1470}; // namespace android
1471