AudioTrack.cpp revision e1c3962e268ffc12bfd1bd9ea84da1f135f36960 
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        audio_format_t 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        audio_format_t 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        audio_format_t 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 == AUDIO_FORMAT_DEFAULT) {
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                                  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 = format;
251    mChannelMask = (uint32_t)channelMask;
252    mChannelCount = channelCount;
253    mSharedBuffer = sharedBuffer;
254    mMuted = false;
255    mActive = 0;
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
287audio_format_t 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 == 0) {
342        mFlushed = false;
343        mActive = 1;
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 = 0;
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 == 1) {
398        mActive = 0;
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    return !mActive;
428}
429
430void AudioTrack::flush()
431{
432    AutoMutex lock(mLock);
433    flush_l();
434}
435
436// must be called with mLock held
437void AudioTrack::flush_l()
438{
439    ALOGV("flush");
440
441    // clear playback marker and periodic update counter
442    mMarkerPosition = 0;
443    mMarkerReached = false;
444    mUpdatePeriod = 0;
445
446    if (!mActive) {
447        mFlushed = true;
448        mAudioTrack->flush();
449        // Release AudioTrack callback thread in case it was waiting for new buffers
450        // in AudioTrack::obtainBuffer()
451        mCblk->cv.signal();
452    }
453}
454
455void AudioTrack::pause()
456{
457    ALOGV("pause");
458    AutoMutex lock(mLock);
459    if (mActive == 1) {
460        mActive = 0;
461        mAudioTrack->pause();
462    }
463}
464
465void AudioTrack::mute(bool e)
466{
467    mAudioTrack->mute(e);
468    mMuted = e;
469}
470
471bool AudioTrack::muted() const
472{
473    return mMuted;
474}
475
476status_t AudioTrack::setVolume(float left, float right)
477{
478    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
479        return BAD_VALUE;
480    }
481
482    AutoMutex lock(mLock);
483    mVolume[LEFT] = left;
484    mVolume[RIGHT] = right;
485
486    // write must be atomic
487    mCblk->volumeLR = (uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000);
488
489    return NO_ERROR;
490}
491
492void AudioTrack::getVolume(float* left, float* right)
493{
494    if (left != NULL) {
495        *left  = mVolume[LEFT];
496    }
497    if (right != NULL) {
498        *right = mVolume[RIGHT];
499    }
500}
501
502status_t AudioTrack::setAuxEffectSendLevel(float level)
503{
504    ALOGV("setAuxEffectSendLevel(%f)", level);
505    if (level > 1.0f) {
506        return BAD_VALUE;
507    }
508    AutoMutex lock(mLock);
509
510    mSendLevel = level;
511
512    mCblk->sendLevel = uint16_t(level * 0x1000);
513
514    return NO_ERROR;
515}
516
517void AudioTrack::getAuxEffectSendLevel(float* level)
518{
519    if (level != NULL) {
520        *level  = mSendLevel;
521    }
522}
523
524status_t AudioTrack::setSampleRate(int rate)
525{
526    int afSamplingRate;
527
528    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
529        return NO_INIT;
530    }
531    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
532    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
533
534    AutoMutex lock(mLock);
535    mCblk->sampleRate = rate;
536    return NO_ERROR;
537}
538
539uint32_t AudioTrack::getSampleRate()
540{
541    AutoMutex lock(mLock);
542    return mCblk->sampleRate;
543}
544
545status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
546{
547    AutoMutex lock(mLock);
548    return setLoop_l(loopStart, loopEnd, loopCount);
549}
550
551// must be called with mLock held
552status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
553{
554    audio_track_cblk_t* cblk = mCblk;
555
556    Mutex::Autolock _l(cblk->lock);
557
558    if (loopCount == 0) {
559        cblk->loopStart = UINT_MAX;
560        cblk->loopEnd = UINT_MAX;
561        cblk->loopCount = 0;
562        mLoopCount = 0;
563        return NO_ERROR;
564    }
565
566    if (loopStart >= loopEnd ||
567        loopEnd - loopStart > cblk->frameCount ||
568        cblk->server > loopStart) {
569        LOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
570        return BAD_VALUE;
571    }
572
573    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
574        LOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
575            loopStart, loopEnd, cblk->frameCount);
576        return BAD_VALUE;
577    }
578
579    cblk->loopStart = loopStart;
580    cblk->loopEnd = loopEnd;
581    cblk->loopCount = loopCount;
582    mLoopCount = loopCount;
583
584    return NO_ERROR;
585}
586
587status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount)
588{
589    AutoMutex lock(mLock);
590    if (loopStart != 0) {
591        *loopStart = mCblk->loopStart;
592    }
593    if (loopEnd != 0) {
594        *loopEnd = mCblk->loopEnd;
595    }
596    if (loopCount != 0) {
597        if (mCblk->loopCount < 0) {
598            *loopCount = -1;
599        } else {
600            *loopCount = mCblk->loopCount;
601        }
602    }
603
604    return NO_ERROR;
605}
606
607status_t AudioTrack::setMarkerPosition(uint32_t marker)
608{
609    if (mCbf == 0) return INVALID_OPERATION;
610
611    mMarkerPosition = marker;
612    mMarkerReached = false;
613
614    return NO_ERROR;
615}
616
617status_t AudioTrack::getMarkerPosition(uint32_t *marker)
618{
619    if (marker == 0) return BAD_VALUE;
620
621    *marker = mMarkerPosition;
622
623    return NO_ERROR;
624}
625
626status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
627{
628    if (mCbf == 0) return INVALID_OPERATION;
629
630    uint32_t curPosition;
631    getPosition(&curPosition);
632    mNewPosition = curPosition + updatePeriod;
633    mUpdatePeriod = updatePeriod;
634
635    return NO_ERROR;
636}
637
638status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod)
639{
640    if (updatePeriod == 0) return BAD_VALUE;
641
642    *updatePeriod = mUpdatePeriod;
643
644    return NO_ERROR;
645}
646
647status_t AudioTrack::setPosition(uint32_t position)
648{
649    AutoMutex lock(mLock);
650    Mutex::Autolock _l(mCblk->lock);
651
652    if (!stopped()) return INVALID_OPERATION;
653
654    if (position > mCblk->user) return BAD_VALUE;
655
656    mCblk->server = position;
657    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
658
659    return NO_ERROR;
660}
661
662status_t AudioTrack::getPosition(uint32_t *position)
663{
664    if (position == 0) return BAD_VALUE;
665    AutoMutex lock(mLock);
666    *position = mFlushed ? 0 : mCblk->server;
667
668    return NO_ERROR;
669}
670
671status_t AudioTrack::reload()
672{
673    AutoMutex lock(mLock);
674
675    if (!stopped()) return INVALID_OPERATION;
676
677    flush_l();
678
679    mCblk->stepUser(mCblk->frameCount);
680
681    return NO_ERROR;
682}
683
684audio_io_handle_t AudioTrack::getOutput()
685{
686    AutoMutex lock(mLock);
687    return getOutput_l();
688}
689
690// must be called with mLock held
691audio_io_handle_t AudioTrack::getOutput_l()
692{
693    return AudioSystem::getOutput((audio_stream_type_t)mStreamType,
694            mCblk->sampleRate, mFormat, mChannelMask, (audio_policy_output_flags_t)mFlags);
695}
696
697int AudioTrack::getSessionId()
698{
699    return mSessionId;
700}
701
702status_t AudioTrack::attachAuxEffect(int effectId)
703{
704    ALOGV("attachAuxEffect(%d)", effectId);
705    status_t status = mAudioTrack->attachAuxEffect(effectId);
706    if (status == NO_ERROR) {
707        mAuxEffectId = effectId;
708    }
709    return status;
710}
711
712// -------------------------------------------------------------------------
713
714// must be called with mLock held
715status_t AudioTrack::createTrack_l(
716        int streamType,
717        uint32_t sampleRate,
718        audio_format_t format,
719        uint32_t channelMask,
720        int frameCount,
721        uint32_t flags,
722        const sp<IMemory>& sharedBuffer,
723        audio_io_handle_t output,
724        bool enforceFrameCount)
725{
726    status_t status;
727    const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
728    if (audioFlinger == 0) {
729       LOGE("Could not get audioflinger");
730       return NO_INIT;
731    }
732
733    int afSampleRate;
734    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
735        return NO_INIT;
736    }
737    int afFrameCount;
738    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
739        return NO_INIT;
740    }
741    uint32_t afLatency;
742    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
743        return NO_INIT;
744    }
745
746    mNotificationFramesAct = mNotificationFramesReq;
747    if (!audio_is_linear_pcm(format)) {
748        if (sharedBuffer != 0) {
749            frameCount = sharedBuffer->size();
750        }
751    } else {
752        // Ensure that buffer depth covers at least audio hardware latency
753        uint32_t minBufCount = afLatency / ((1000 * afFrameCount)/afSampleRate);
754        if (minBufCount < 2) minBufCount = 2;
755
756        int minFrameCount = (afFrameCount*sampleRate*minBufCount)/afSampleRate;
757
758        if (sharedBuffer == 0) {
759            if (frameCount == 0) {
760                frameCount = minFrameCount;
761            }
762            if (mNotificationFramesAct == 0) {
763                mNotificationFramesAct = frameCount/2;
764            }
765            // Make sure that application is notified with sufficient margin
766            // before underrun
767            if (mNotificationFramesAct > (uint32_t)frameCount/2) {
768                mNotificationFramesAct = frameCount/2;
769            }
770            if (frameCount < minFrameCount) {
771                if (enforceFrameCount) {
772                    LOGE("Invalid buffer size: minFrameCount %d, frameCount %d", minFrameCount, frameCount);
773                    return BAD_VALUE;
774                } else {
775                    frameCount = minFrameCount;
776                }
777            }
778        } else {
779            // Ensure that buffer alignment matches channelcount
780            int channelCount = popcount(channelMask);
781            if (((uint32_t)sharedBuffer->pointer() & (channelCount | 1)) != 0) {
782                LOGE("Invalid buffer alignement: address %p, channelCount %d", sharedBuffer->pointer(), channelCount);
783                return BAD_VALUE;
784            }
785            frameCount = sharedBuffer->size()/channelCount/sizeof(int16_t);
786        }
787    }
788
789    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
790                                                      streamType,
791                                                      sampleRate,
792                                                      format,
793                                                      channelMask,
794                                                      frameCount,
795                                                      ((uint16_t)flags) << 16,
796                                                      sharedBuffer,
797                                                      output,
798                                                      &mSessionId,
799                                                      &status);
800
801    if (track == 0) {
802        LOGE("AudioFlinger could not create track, status: %d", status);
803        return status;
804    }
805    sp<IMemory> cblk = track->getCblk();
806    if (cblk == 0) {
807        LOGE("Could not get control block");
808        return NO_INIT;
809    }
810    mAudioTrack = track;
811    mCblkMemory = cblk;
812    mCblk = static_cast<audio_track_cblk_t*>(cblk->pointer());
813    android_atomic_or(CBLK_DIRECTION_OUT, &mCblk->flags);
814    if (sharedBuffer == 0) {
815        mCblk->buffers = (char*)mCblk + sizeof(audio_track_cblk_t);
816    } else {
817        mCblk->buffers = sharedBuffer->pointer();
818         // Force buffer full condition as data is already present in shared memory
819        mCblk->stepUser(mCblk->frameCount);
820    }
821
822    mCblk->volumeLR = (uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000);
823    mCblk->sendLevel = uint16_t(mSendLevel * 0x1000);
824    mAudioTrack->attachAuxEffect(mAuxEffectId);
825    mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
826    mCblk->waitTimeMs = 0;
827    mRemainingFrames = mNotificationFramesAct;
828    mLatency = afLatency + (1000*mCblk->frameCount) / sampleRate;
829    return NO_ERROR;
830}
831
832status_t AudioTrack::obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
833{
834    AutoMutex lock(mLock);
835    int active;
836    status_t result = NO_ERROR;
837    audio_track_cblk_t* cblk = mCblk;
838    uint32_t framesReq = audioBuffer->frameCount;
839    uint32_t waitTimeMs = (waitCount < 0) ? cblk->bufferTimeoutMs : WAIT_PERIOD_MS;
840
841    audioBuffer->frameCount  = 0;
842    audioBuffer->size = 0;
843
844    uint32_t framesAvail = cblk->framesAvailable();
845
846    cblk->lock.lock();
847    if (cblk->flags & CBLK_INVALID_MSK) {
848        goto create_new_track;
849    }
850    cblk->lock.unlock();
851
852    if (framesAvail == 0) {
853        cblk->lock.lock();
854        goto start_loop_here;
855        while (framesAvail == 0) {
856            active = mActive;
857            if (CC_UNLIKELY(!active)) {
858                ALOGV("Not active and NO_MORE_BUFFERS");
859                cblk->lock.unlock();
860                return NO_MORE_BUFFERS;
861            }
862            if (CC_UNLIKELY(!waitCount)) {
863                cblk->lock.unlock();
864                return WOULD_BLOCK;
865            }
866            if (!(cblk->flags & CBLK_INVALID_MSK)) {
867                mLock.unlock();
868                result = cblk->cv.waitRelative(cblk->lock, milliseconds(waitTimeMs));
869                cblk->lock.unlock();
870                mLock.lock();
871                if (mActive == 0) {
872                    return status_t(STOPPED);
873                }
874                cblk->lock.lock();
875            }
876
877            if (cblk->flags & CBLK_INVALID_MSK) {
878                goto create_new_track;
879            }
880            if (CC_UNLIKELY(result != NO_ERROR)) {
881                cblk->waitTimeMs += waitTimeMs;
882                if (cblk->waitTimeMs >= cblk->bufferTimeoutMs) {
883                    // timing out when a loop has been set and we have already written upto loop end
884                    // is a normal condition: no need to wake AudioFlinger up.
885                    if (cblk->user < cblk->loopEnd) {
886                        LOGW(   "obtainBuffer timed out (is the CPU pegged?) %p "
887                                "user=%08x, server=%08x", this, cblk->user, cblk->server);
888                        //unlock cblk mutex before calling mAudioTrack->start() (see issue #1617140)
889                        cblk->lock.unlock();
890                        result = mAudioTrack->start();
891                        cblk->lock.lock();
892                        if (result == DEAD_OBJECT) {
893                            android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
894create_new_track:
895                            result = restoreTrack_l(cblk, false);
896                        }
897                        if (result != NO_ERROR) {
898                            LOGW("obtainBuffer create Track error %d", result);
899                            cblk->lock.unlock();
900                            return result;
901                        }
902                    }
903                    cblk->waitTimeMs = 0;
904                }
905
906                if (--waitCount == 0) {
907                    cblk->lock.unlock();
908                    return TIMED_OUT;
909                }
910            }
911            // read the server count again
912        start_loop_here:
913            framesAvail = cblk->framesAvailable_l();
914        }
915        cblk->lock.unlock();
916    }
917
918    // restart track if it was disabled by audioflinger due to previous underrun
919    if (mActive && (cblk->flags & CBLK_DISABLED_MSK)) {
920        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
921        LOGW("obtainBuffer() track %p disabled, restarting", this);
922        mAudioTrack->start();
923    }
924
925    cblk->waitTimeMs = 0;
926
927    if (framesReq > framesAvail) {
928        framesReq = framesAvail;
929    }
930
931    uint32_t u = cblk->user;
932    uint32_t bufferEnd = cblk->userBase + cblk->frameCount;
933
934    if (u + framesReq > bufferEnd) {
935        framesReq = bufferEnd - u;
936    }
937
938    audioBuffer->flags = mMuted ? Buffer::MUTE : 0;
939    audioBuffer->channelCount = mChannelCount;
940    audioBuffer->frameCount = framesReq;
941    audioBuffer->size = framesReq * cblk->frameSize;
942    if (audio_is_linear_pcm(mFormat)) {
943        audioBuffer->format = AUDIO_FORMAT_PCM_16_BIT;
944    } else {
945        audioBuffer->format = mFormat;
946    }
947    audioBuffer->raw = (int8_t *)cblk->buffer(u);
948    active = mActive;
949    return active ? status_t(NO_ERROR) : status_t(STOPPED);
950}
951
952void AudioTrack::releaseBuffer(Buffer* audioBuffer)
953{
954    AutoMutex lock(mLock);
955    mCblk->stepUser(audioBuffer->frameCount);
956}
957
958// -------------------------------------------------------------------------
959
960ssize_t AudioTrack::write(const void* buffer, size_t userSize)
961{
962
963    if (mSharedBuffer != 0) return INVALID_OPERATION;
964
965    if (ssize_t(userSize) < 0) {
966        // sanity-check. user is most-likely passing an error code.
967        LOGE("AudioTrack::write(buffer=%p, size=%u (%d)",
968                buffer, userSize, userSize);
969        return BAD_VALUE;
970    }
971
972    ALOGV("write %p: %d bytes, mActive=%d", this, userSize, mActive);
973
974    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
975    // while we are accessing the cblk
976    mLock.lock();
977    sp <IAudioTrack> audioTrack = mAudioTrack;
978    sp <IMemory> iMem = mCblkMemory;
979    mLock.unlock();
980
981    ssize_t written = 0;
982    const int8_t *src = (const int8_t *)buffer;
983    Buffer audioBuffer;
984    size_t frameSz = (size_t)frameSize();
985
986    do {
987        audioBuffer.frameCount = userSize/frameSz;
988
989        // Calling obtainBuffer() with a negative wait count causes
990        // an (almost) infinite wait time.
991        status_t err = obtainBuffer(&audioBuffer, -1);
992        if (err < 0) {
993            // out of buffers, return #bytes written
994            if (err == status_t(NO_MORE_BUFFERS))
995                break;
996            return ssize_t(err);
997        }
998
999        size_t toWrite;
1000
1001        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1002            // Divide capacity by 2 to take expansion into account
1003            toWrite = audioBuffer.size>>1;
1004            // 8 to 16 bit conversion
1005            int count = toWrite;
1006            int16_t *dst = (int16_t *)(audioBuffer.i8);
1007            while(count--) {
1008                *dst++ = (int16_t)(*src++^0x80) << 8;
1009            }
1010        } else {
1011            toWrite = audioBuffer.size;
1012            memcpy(audioBuffer.i8, src, toWrite);
1013            src += toWrite;
1014        }
1015        userSize -= toWrite;
1016        written += toWrite;
1017
1018        releaseBuffer(&audioBuffer);
1019    } while (userSize >= frameSz);
1020
1021    return written;
1022}
1023
1024// -------------------------------------------------------------------------
1025
1026bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1027{
1028    Buffer audioBuffer;
1029    uint32_t frames;
1030    size_t writtenSize;
1031
1032    mLock.lock();
1033    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1034    // while we are accessing the cblk
1035    sp <IAudioTrack> audioTrack = mAudioTrack;
1036    sp <IMemory> iMem = mCblkMemory;
1037    audio_track_cblk_t* cblk = mCblk;
1038    mLock.unlock();
1039
1040    // Manage underrun callback
1041    if (mActive && (cblk->framesAvailable() == cblk->frameCount)) {
1042        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1043        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1044            mCbf(EVENT_UNDERRUN, mUserData, 0);
1045            if (cblk->server == cblk->frameCount) {
1046                mCbf(EVENT_BUFFER_END, mUserData, 0);
1047            }
1048            if (mSharedBuffer != 0) return false;
1049        }
1050    }
1051
1052    // Manage loop end callback
1053    while (mLoopCount > cblk->loopCount) {
1054        int loopCount = -1;
1055        mLoopCount--;
1056        if (mLoopCount >= 0) loopCount = mLoopCount;
1057
1058        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1059    }
1060
1061    // Manage marker callback
1062    if (!mMarkerReached && (mMarkerPosition > 0)) {
1063        if (cblk->server >= mMarkerPosition) {
1064            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1065            mMarkerReached = true;
1066        }
1067    }
1068
1069    // Manage new position callback
1070    if (mUpdatePeriod > 0) {
1071        while (cblk->server >= mNewPosition) {
1072            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1073            mNewPosition += mUpdatePeriod;
1074        }
1075    }
1076
1077    // If Shared buffer is used, no data is requested from client.
1078    if (mSharedBuffer != 0) {
1079        frames = 0;
1080    } else {
1081        frames = mRemainingFrames;
1082    }
1083
1084    int32_t waitCount = -1;
1085    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1086        waitCount = 1;
1087    }
1088
1089    do {
1090
1091        audioBuffer.frameCount = frames;
1092
1093        // Calling obtainBuffer() with a wait count of 1
1094        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1095        // stuck here not being able to handle timed events (position, markers, loops).
1096        status_t err = obtainBuffer(&audioBuffer, waitCount);
1097        if (err < NO_ERROR) {
1098            if (err != TIMED_OUT) {
1099                LOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1100                return false;
1101            }
1102            break;
1103        }
1104        if (err == status_t(STOPPED)) return false;
1105
1106        // Divide buffer size by 2 to take into account the expansion
1107        // due to 8 to 16 bit conversion: the callback must fill only half
1108        // of the destination buffer
1109        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1110            audioBuffer.size >>= 1;
1111        }
1112
1113        size_t reqSize = audioBuffer.size;
1114        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1115        writtenSize = audioBuffer.size;
1116
1117        // Sanity check on returned size
1118        if (ssize_t(writtenSize) <= 0) {
1119            // The callback is done filling buffers
1120            // Keep this thread going to handle timed events and
1121            // still try to get more data in intervals of WAIT_PERIOD_MS
1122            // but don't just loop and block the CPU, so wait
1123            usleep(WAIT_PERIOD_MS*1000);
1124            break;
1125        }
1126        if (writtenSize > reqSize) writtenSize = reqSize;
1127
1128        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1129            // 8 to 16 bit conversion
1130            const int8_t *src = audioBuffer.i8 + writtenSize-1;
1131            int count = writtenSize;
1132            int16_t *dst = audioBuffer.i16 + writtenSize-1;
1133            while(count--) {
1134                *dst-- = (int16_t)(*src--^0x80) << 8;
1135            }
1136            writtenSize <<= 1;
1137        }
1138
1139        audioBuffer.size = writtenSize;
1140        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1141        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sampel size of
1142        // 16 bit.
1143        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1144
1145        frames -= audioBuffer.frameCount;
1146
1147        releaseBuffer(&audioBuffer);
1148    }
1149    while (frames);
1150
1151    if (frames == 0) {
1152        mRemainingFrames = mNotificationFramesAct;
1153    } else {
1154        mRemainingFrames = frames;
1155    }
1156    return true;
1157}
1158
1159// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1160// the IAudioTrack and IMemory in case they are recreated here.
1161// If the IAudioTrack is successfully restored, the cblk pointer is updated
1162status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1163{
1164    status_t result;
1165
1166    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1167        LOGW("dead IAudioTrack, creating a new one from %s TID %d",
1168             fromStart ? "start()" : "obtainBuffer()", gettid());
1169
1170        // signal old cblk condition so that other threads waiting for available buffers stop
1171        // waiting now
1172        cblk->cv.broadcast();
1173        cblk->lock.unlock();
1174
1175        // refresh the audio configuration cache in this process to make sure we get new
1176        // output parameters in getOutput_l() and createTrack_l()
1177        AudioSystem::clearAudioConfigCache();
1178
1179        // if the new IAudioTrack is created, createTrack_l() will modify the
1180        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1181        // It will also delete the strong references on previous IAudioTrack and IMemory
1182        result = createTrack_l(mStreamType,
1183                               cblk->sampleRate,
1184                               mFormat,
1185                               mChannelMask,
1186                               mFrameCount,
1187                               mFlags,
1188                               mSharedBuffer,
1189                               getOutput_l(),
1190                               false);
1191
1192        if (result == NO_ERROR) {
1193            uint32_t user = cblk->user;
1194            uint32_t server = cblk->server;
1195            // restore write index and set other indexes to reflect empty buffer status
1196            mCblk->user = user;
1197            mCblk->server = user;
1198            mCblk->userBase = user;
1199            mCblk->serverBase = user;
1200            // restore loop: this is not guaranteed to succeed if new frame count is not
1201            // compatible with loop length
1202            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1203            if (!fromStart) {
1204                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1205                // Make sure that a client relying on callback events indicating underrun or
1206                // the actual amount of audio frames played (e.g SoundPool) receives them.
1207                if (mSharedBuffer == 0) {
1208                    uint32_t frames = 0;
1209                    if (user > server) {
1210                        frames = ((user - server) > mCblk->frameCount) ?
1211                                mCblk->frameCount : (user - server);
1212                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1213                    }
1214                    // restart playback even if buffer is not completely filled.
1215                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1216                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1217                    // the client
1218                    mCblk->stepUser(frames);
1219                }
1220            }
1221            if (mActive) {
1222                result = mAudioTrack->start();
1223                LOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1224            }
1225            if (fromStart && result == NO_ERROR) {
1226                mNewPosition = mCblk->server + mUpdatePeriod;
1227            }
1228        }
1229        if (result != NO_ERROR) {
1230            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1231            LOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1232        }
1233        mRestoreStatus = result;
1234        // signal old cblk condition for other threads waiting for restore completion
1235        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1236        cblk->cv.broadcast();
1237    } else {
1238        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1239            LOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1240            mLock.unlock();
1241            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1242            if (result == NO_ERROR) {
1243                result = mRestoreStatus;
1244            }
1245            cblk->lock.unlock();
1246            mLock.lock();
1247        } else {
1248            LOGW("dead IAudioTrack, already restored TID %d", gettid());
1249            result = mRestoreStatus;
1250            cblk->lock.unlock();
1251        }
1252    }
1253    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1254         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1255
1256    if (result == NO_ERROR) {
1257        // from now on we switch to the newly created cblk
1258        cblk = mCblk;
1259    }
1260    cblk->lock.lock();
1261
1262    LOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1263
1264    return result;
1265}
1266
1267status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1268{
1269
1270    const size_t SIZE = 256;
1271    char buffer[SIZE];
1272    String8 result;
1273
1274    result.append(" AudioTrack::dump\n");
1275    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1276    result.append(buffer);
1277    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1278    result.append(buffer);
1279    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1280    result.append(buffer);
1281    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1282    result.append(buffer);
1283    ::write(fd, result.string(), result.size());
1284    return NO_ERROR;
1285}
1286
1287// =========================================================================
1288
1289AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1290    : Thread(bCanCallJava), mReceiver(receiver)
1291{
1292}
1293
1294bool AudioTrack::AudioTrackThread::threadLoop()
1295{
1296    return mReceiver.processAudioBuffer(this);
1297}
1298
1299status_t AudioTrack::AudioTrackThread::readyToRun()
1300{
1301    return NO_ERROR;
1302}
1303
1304void AudioTrack::AudioTrackThread::onFirstRef()
1305{
1306}
1307
1308// =========================================================================
1309
1310
1311audio_track_cblk_t::audio_track_cblk_t()
1312    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1313    userBase(0), serverBase(0), buffers(0), frameCount(0),
1314    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), volumeLR(0),
1315    sendLevel(0), flags(0)
1316{
1317}
1318
1319uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1320{
1321    uint32_t u = user;
1322
1323    u += frameCount;
1324    // Ensure that user is never ahead of server for AudioRecord
1325    if (flags & CBLK_DIRECTION_MSK) {
1326        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1327        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1328            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1329        }
1330    } else if (u > server) {
1331        LOGW("stepServer occurred after track reset");
1332        u = server;
1333    }
1334
1335    if (u >= userBase + this->frameCount) {
1336        userBase += this->frameCount;
1337    }
1338
1339    user = u;
1340
1341    // Clear flow control error condition as new data has been written/read to/from buffer.
1342    if (flags & CBLK_UNDERRUN_MSK) {
1343        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1344    }
1345
1346    return u;
1347}
1348
1349bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1350{
1351    if (!tryLock()) {
1352        LOGW("stepServer() could not lock cblk");
1353        return false;
1354    }
1355
1356    uint32_t s = server;
1357
1358    s += frameCount;
1359    if (flags & CBLK_DIRECTION_MSK) {
1360        // Mark that we have read the first buffer so that next time stepUser() is called
1361        // we switch to normal obtainBuffer() timeout period
1362        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1363            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1364        }
1365        // It is possible that we receive a flush()
1366        // while the mixer is processing a block: in this case,
1367        // stepServer() is called After the flush() has reset u & s and
1368        // we have s > u
1369        if (s > user) {
1370            LOGW("stepServer occurred after track reset");
1371            s = user;
1372        }
1373    }
1374
1375    if (s >= loopEnd) {
1376        LOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1377        s = loopStart;
1378        if (--loopCount == 0) {
1379            loopEnd = UINT_MAX;
1380            loopStart = UINT_MAX;
1381        }
1382    }
1383    if (s >= serverBase + this->frameCount) {
1384        serverBase += this->frameCount;
1385    }
1386
1387    server = s;
1388
1389    if (!(flags & CBLK_INVALID_MSK)) {
1390        cv.signal();
1391    }
1392    lock.unlock();
1393    return true;
1394}
1395
1396void* audio_track_cblk_t::buffer(uint32_t offset) const
1397{
1398    return (int8_t *)buffers + (offset - userBase) * frameSize;
1399}
1400
1401uint32_t audio_track_cblk_t::framesAvailable()
1402{
1403    Mutex::Autolock _l(lock);
1404    return framesAvailable_l();
1405}
1406
1407uint32_t audio_track_cblk_t::framesAvailable_l()
1408{
1409    uint32_t u = user;
1410    uint32_t s = server;
1411
1412    if (flags & CBLK_DIRECTION_MSK) {
1413        uint32_t limit = (s < loopStart) ? s : loopStart;
1414        return limit + frameCount - u;
1415    } else {
1416        return frameCount + u - s;
1417    }
1418}
1419
1420uint32_t audio_track_cblk_t::framesReady()
1421{
1422    uint32_t u = user;
1423    uint32_t s = server;
1424
1425    if (flags & CBLK_DIRECTION_MSK) {
1426        if (u < loopEnd) {
1427            return u - s;
1428        } else {
1429            // do not block on mutex shared with client on AudioFlinger side
1430            if (!tryLock()) {
1431                LOGW("framesReady() could not lock cblk");
1432                return 0;
1433            }
1434            uint32_t frames = UINT_MAX;
1435            if (loopCount >= 0) {
1436                frames = (loopEnd - loopStart)*loopCount + u - s;
1437            }
1438            lock.unlock();
1439            return frames;
1440        }
1441    } else {
1442        return s - u;
1443    }
1444}
1445
1446bool audio_track_cblk_t::tryLock()
1447{
1448    // the code below simulates lock-with-timeout
1449    // we MUST do this to protect the AudioFlinger server
1450    // as this lock is shared with the client.
1451    status_t err;
1452
1453    err = lock.tryLock();
1454    if (err == -EBUSY) { // just wait a bit
1455        usleep(1000);
1456        err = lock.tryLock();
1457    }
1458    if (err != NO_ERROR) {
1459        // probably, the client just died.
1460        return false;
1461    }
1462    return true;
1463}
1464
1465// -------------------------------------------------------------------------
1466
1467}; // namespace android
1468