AudioTrack.cpp revision 511754b5839fd9b09fc56b89ae007fbc39084a33 
1/* frameworks/base/media/libmedia/AudioTrack.cpp
2**
3** Copyright 2007, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18
19//#define LOG_NDEBUG 0
20#define LOG_TAG "AudioTrack"
21
22#include <stdint.h>
23#include <sys/types.h>
24#include <limits.h>
25
26#include <sched.h>
27#include <sys/resource.h>
28
29#include <private/media/AudioTrackShared.h>
30
31#include <media/AudioSystem.h>
32#include <media/AudioTrack.h>
33
34#include <utils/Log.h>
35#include <binder/Parcel.h>
36#include <binder/IPCThreadState.h>
37#include <utils/Timers.h>
38#include <utils/Atomic.h>
39
40#include <cutils/bitops.h>
41#include <cutils/compiler.h>
42
43#include <system/audio.h>
44#include <system/audio_policy.h>
45
46#include <audio_utils/primitives.h>
47
48namespace android {
49// ---------------------------------------------------------------------------
50
51// static
52status_t AudioTrack::getMinFrameCount(
53        int* frameCount,
54        audio_stream_type_t streamType,
55        uint32_t sampleRate)
56{
57    int afSampleRate;
58    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
59        return NO_INIT;
60    }
61    int afFrameCount;
62    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
63        return NO_INIT;
64    }
65    uint32_t afLatency;
66    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
67        return NO_INIT;
68    }
69
70    // Ensure that buffer depth covers at least audio hardware latency
71    uint32_t minBufCount = afLatency / ((1000 * afFrameCount) / afSampleRate);
72    if (minBufCount < 2) minBufCount = 2;
73
74    *frameCount = (sampleRate == 0) ? afFrameCount * minBufCount :
75              afFrameCount * minBufCount * sampleRate / afSampleRate;
76    return NO_ERROR;
77}
78
79// ---------------------------------------------------------------------------
80
81AudioTrack::AudioTrack()
82    : mStatus(NO_INIT),
83      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
84{
85}
86
87AudioTrack::AudioTrack(
88        audio_stream_type_t streamType,
89        uint32_t sampleRate,
90        audio_format_t format,
91        int channelMask,
92        int frameCount,
93        uint32_t flags,
94        callback_t cbf,
95        void* user,
96        int notificationFrames,
97        int sessionId)
98    : mStatus(NO_INIT),
99      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
100{
101    mStatus = set(streamType, sampleRate, format, channelMask,
102            frameCount, flags, cbf, user, notificationFrames,
103            0, false, sessionId);
104}
105
106AudioTrack::AudioTrack(
107        audio_stream_type_t streamType,
108        uint32_t sampleRate,
109        audio_format_t format,
110        int channelMask,
111        const sp<IMemory>& sharedBuffer,
112        uint32_t flags,
113        callback_t cbf,
114        void* user,
115        int notificationFrames,
116        int sessionId)
117    : mStatus(NO_INIT),
118      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
119{
120    mStatus = set(streamType, sampleRate, format, channelMask,
121            0, flags, cbf, user, notificationFrames,
122            sharedBuffer, false, sessionId);
123}
124
125AudioTrack::~AudioTrack()
126{
127    ALOGV_IF(mSharedBuffer != 0, "Destructor sharedBuffer: %p", mSharedBuffer->pointer());
128
129    if (mStatus == NO_ERROR) {
130        // Make sure that callback function exits in the case where
131        // it is looping on buffer full condition in obtainBuffer().
132        // Otherwise the callback thread will never exit.
133        stop();
134        if (mAudioTrackThread != 0) {
135            mAudioTrackThread->requestExitAndWait();
136            mAudioTrackThread.clear();
137        }
138        mAudioTrack.clear();
139        IPCThreadState::self()->flushCommands();
140        AudioSystem::releaseAudioSessionId(mSessionId);
141    }
142}
143
144status_t AudioTrack::set(
145        audio_stream_type_t streamType,
146        uint32_t sampleRate,
147        audio_format_t format,
148        int channelMask,
149        int frameCount,
150        uint32_t flags,
151        callback_t cbf,
152        void* user,
153        int notificationFrames,
154        const sp<IMemory>& sharedBuffer,
155        bool threadCanCallJava,
156        int sessionId)
157{
158
159    ALOGV_IF(sharedBuffer != 0, "sharedBuffer: %p, size: %d", sharedBuffer->pointer(), sharedBuffer->size());
160
161    AutoMutex lock(mLock);
162    if (mAudioTrack != 0) {
163        ALOGE("Track already in use");
164        return INVALID_OPERATION;
165    }
166
167    int afSampleRate;
168    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
169        return NO_INIT;
170    }
171    uint32_t afLatency;
172    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
173        return NO_INIT;
174    }
175
176    // handle default values first.
177    if (streamType == AUDIO_STREAM_DEFAULT) {
178        streamType = AUDIO_STREAM_MUSIC;
179    }
180    if (sampleRate == 0) {
181        sampleRate = afSampleRate;
182    }
183    // these below should probably come from the audioFlinger too...
184    if (format == AUDIO_FORMAT_DEFAULT) {
185        format = AUDIO_FORMAT_PCM_16_BIT;
186    }
187    if (channelMask == 0) {
188        channelMask = AUDIO_CHANNEL_OUT_STEREO;
189    }
190
191    // validate parameters
192    if (!audio_is_valid_format(format)) {
193        ALOGE("Invalid format");
194        return BAD_VALUE;
195    }
196
197    // force direct flag if format is not linear PCM
198    if (!audio_is_linear_pcm(format)) {
199        flags |= AUDIO_POLICY_OUTPUT_FLAG_DIRECT;
200    }
201
202    if (!audio_is_output_channel(channelMask)) {
203        ALOGE("Invalid channel mask");
204        return BAD_VALUE;
205    }
206    uint32_t channelCount = popcount(channelMask);
207
208    audio_io_handle_t output = AudioSystem::getOutput(
209                                    streamType,
210                                    sampleRate, format, channelMask,
211                                    (audio_policy_output_flags_t)flags);
212
213    if (output == 0) {
214        ALOGE("Could not get audio output for stream type %d", streamType);
215        return BAD_VALUE;
216    }
217
218    mVolume[LEFT] = 1.0f;
219    mVolume[RIGHT] = 1.0f;
220    mSendLevel = 0.0f;
221    mFrameCount = frameCount;
222    mNotificationFramesReq = notificationFrames;
223    mSessionId = sessionId;
224    mAuxEffectId = 0;
225
226    // create the IAudioTrack
227    status_t status = createTrack_l(streamType,
228                                  sampleRate,
229                                  format,
230                                  (uint32_t)channelMask,
231                                  frameCount,
232                                  flags,
233                                  sharedBuffer,
234                                  output,
235                                  true);
236
237    if (status != NO_ERROR) {
238        return status;
239    }
240
241    if (cbf != 0) {
242        mAudioTrackThread = new AudioTrackThread(*this, threadCanCallJava);
243    }
244
245    mStatus = NO_ERROR;
246
247    mStreamType = streamType;
248    mFormat = format;
249    mChannelMask = (uint32_t)channelMask;
250    mChannelCount = channelCount;
251    mSharedBuffer = sharedBuffer;
252    mMuted = false;
253    mActive = false;
254    mCbf = cbf;
255    mUserData = user;
256    mLoopCount = 0;
257    mMarkerPosition = 0;
258    mMarkerReached = false;
259    mNewPosition = 0;
260    mUpdatePeriod = 0;
261    mFlushed = false;
262    mFlags = flags;
263    AudioSystem::acquireAudioSessionId(mSessionId);
264    mRestoreStatus = NO_ERROR;
265    return NO_ERROR;
266}
267
268status_t AudioTrack::initCheck() const
269{
270    return mStatus;
271}
272
273// -------------------------------------------------------------------------
274
275uint32_t AudioTrack::latency() const
276{
277    return mLatency;
278}
279
280audio_stream_type_t AudioTrack::streamType() const
281{
282    return mStreamType;
283}
284
285audio_format_t AudioTrack::format() const
286{
287    return mFormat;
288}
289
290int AudioTrack::channelCount() const
291{
292    return mChannelCount;
293}
294
295uint32_t AudioTrack::frameCount() const
296{
297    return mCblk->frameCount;
298}
299
300size_t AudioTrack::frameSize() const
301{
302    if (audio_is_linear_pcm(mFormat)) {
303        return channelCount()*audio_bytes_per_sample(mFormat);
304    } else {
305        return sizeof(uint8_t);
306    }
307}
308
309sp<IMemory>& AudioTrack::sharedBuffer()
310{
311    return mSharedBuffer;
312}
313
314// -------------------------------------------------------------------------
315
316void AudioTrack::start()
317{
318    sp<AudioTrackThread> t = mAudioTrackThread;
319    status_t status = NO_ERROR;
320
321    ALOGV("start %p", this);
322    if (t != 0) {
323        if (t->exitPending()) {
324            if (t->requestExitAndWait() == WOULD_BLOCK) {
325                ALOGE("AudioTrack::start called from thread");
326                return;
327            }
328        }
329        t->mLock.lock();
330     }
331
332    AutoMutex lock(mLock);
333    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
334    // while we are accessing the cblk
335    sp <IAudioTrack> audioTrack = mAudioTrack;
336    sp <IMemory> iMem = mCblkMemory;
337    audio_track_cblk_t* cblk = mCblk;
338
339    if (!mActive) {
340        mFlushed = false;
341        mActive = true;
342        mNewPosition = cblk->server + mUpdatePeriod;
343        cblk->lock.lock();
344        cblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
345        cblk->waitTimeMs = 0;
346        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
347        if (t != 0) {
348            t->run("AudioTrackThread", ANDROID_PRIORITY_AUDIO);
349        } else {
350            mPreviousPriority = getpriority(PRIO_PROCESS, 0);
351            mPreviousSchedulingGroup = androidGetThreadSchedulingGroup(0);
352            androidSetThreadPriority(0, ANDROID_PRIORITY_AUDIO);
353        }
354
355        ALOGV("start %p before lock cblk %p", this, mCblk);
356        if (!(cblk->flags & CBLK_INVALID_MSK)) {
357            cblk->lock.unlock();
358            status = mAudioTrack->start();
359            cblk->lock.lock();
360            if (status == DEAD_OBJECT) {
361                android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
362            }
363        }
364        if (cblk->flags & CBLK_INVALID_MSK) {
365            status = restoreTrack_l(cblk, true);
366        }
367        cblk->lock.unlock();
368        if (status != NO_ERROR) {
369            ALOGV("start() failed");
370            mActive = false;
371            if (t != 0) {
372                t->requestExit();
373            } else {
374                setpriority(PRIO_PROCESS, 0, mPreviousPriority);
375                androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
376            }
377        }
378    }
379
380    if (t != 0) {
381        t->mLock.unlock();
382    }
383}
384
385void AudioTrack::stop()
386{
387    sp<AudioTrackThread> t = mAudioTrackThread;
388
389    ALOGV("stop %p", this);
390    if (t != 0) {
391        t->mLock.lock();
392    }
393
394    AutoMutex lock(mLock);
395    if (mActive) {
396        mActive = false;
397        mCblk->cv.signal();
398        mAudioTrack->stop();
399        // Cancel loops (If we are in the middle of a loop, playback
400        // would not stop until loopCount reaches 0).
401        setLoop_l(0, 0, 0);
402        // the playback head position will reset to 0, so if a marker is set, we need
403        // to activate it again
404        mMarkerReached = false;
405        // Force flush if a shared buffer is used otherwise audioflinger
406        // will not stop before end of buffer is reached.
407        if (mSharedBuffer != 0) {
408            flush_l();
409        }
410        if (t != 0) {
411            t->requestExit();
412        } else {
413            setpriority(PRIO_PROCESS, 0, mPreviousPriority);
414            androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
415        }
416    }
417
418    if (t != 0) {
419        t->mLock.unlock();
420    }
421}
422
423bool AudioTrack::stopped() const
424{
425    AutoMutex lock(mLock);
426    return stopped_l();
427}
428
429void AudioTrack::flush()
430{
431    AutoMutex lock(mLock);
432    flush_l();
433}
434
435// must be called with mLock held
436void AudioTrack::flush_l()
437{
438    ALOGV("flush");
439
440    // clear playback marker and periodic update counter
441    mMarkerPosition = 0;
442    mMarkerReached = false;
443    mUpdatePeriod = 0;
444
445    if (!mActive) {
446        mFlushed = true;
447        mAudioTrack->flush();
448        // Release AudioTrack callback thread in case it was waiting for new buffers
449        // in AudioTrack::obtainBuffer()
450        mCblk->cv.signal();
451    }
452}
453
454void AudioTrack::pause()
455{
456    ALOGV("pause");
457    AutoMutex lock(mLock);
458    if (mActive) {
459        mActive = false;
460        mAudioTrack->pause();
461    }
462}
463
464void AudioTrack::mute(bool e)
465{
466    mAudioTrack->mute(e);
467    mMuted = e;
468}
469
470bool AudioTrack::muted() const
471{
472    return mMuted;
473}
474
475status_t AudioTrack::setVolume(float left, float right)
476{
477    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
478        return BAD_VALUE;
479    }
480
481    AutoMutex lock(mLock);
482    mVolume[LEFT] = left;
483    mVolume[RIGHT] = right;
484
485    // write must be atomic
486    mCblk->volumeLR = (uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000);
487
488    return NO_ERROR;
489}
490
491void AudioTrack::getVolume(float* left, float* right)
492{
493    if (left != NULL) {
494        *left  = mVolume[LEFT];
495    }
496    if (right != NULL) {
497        *right = mVolume[RIGHT];
498    }
499}
500
501status_t AudioTrack::setAuxEffectSendLevel(float level)
502{
503    ALOGV("setAuxEffectSendLevel(%f)", level);
504    if (level < 0.0f || level > 1.0f) {
505        return BAD_VALUE;
506    }
507    AutoMutex lock(mLock);
508
509    mSendLevel = level;
510
511    mCblk->setSendLevel(level);
512
513    return NO_ERROR;
514}
515
516void AudioTrack::getAuxEffectSendLevel(float* level)
517{
518    if (level != NULL) {
519        *level  = mSendLevel;
520    }
521}
522
523status_t AudioTrack::setSampleRate(int rate)
524{
525    int afSamplingRate;
526
527    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
528        return NO_INIT;
529    }
530    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
531    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
532
533    AutoMutex lock(mLock);
534    mCblk->sampleRate = rate;
535    return NO_ERROR;
536}
537
538uint32_t AudioTrack::getSampleRate()
539{
540    AutoMutex lock(mLock);
541    return mCblk->sampleRate;
542}
543
544status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
545{
546    AutoMutex lock(mLock);
547    return setLoop_l(loopStart, loopEnd, loopCount);
548}
549
550// must be called with mLock held
551status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
552{
553    audio_track_cblk_t* cblk = mCblk;
554
555    Mutex::Autolock _l(cblk->lock);
556
557    if (loopCount == 0) {
558        cblk->loopStart = UINT_MAX;
559        cblk->loopEnd = UINT_MAX;
560        cblk->loopCount = 0;
561        mLoopCount = 0;
562        return NO_ERROR;
563    }
564
565    if (loopStart >= loopEnd ||
566        loopEnd - loopStart > cblk->frameCount ||
567        cblk->server > loopStart) {
568        ALOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
569        return BAD_VALUE;
570    }
571
572    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
573        ALOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
574            loopStart, loopEnd, cblk->frameCount);
575        return BAD_VALUE;
576    }
577
578    cblk->loopStart = loopStart;
579    cblk->loopEnd = loopEnd;
580    cblk->loopCount = loopCount;
581    mLoopCount = loopCount;
582
583    return NO_ERROR;
584}
585
586status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount)
587{
588    AutoMutex lock(mLock);
589    if (loopStart != 0) {
590        *loopStart = mCblk->loopStart;
591    }
592    if (loopEnd != 0) {
593        *loopEnd = mCblk->loopEnd;
594    }
595    if (loopCount != 0) {
596        if (mCblk->loopCount < 0) {
597            *loopCount = -1;
598        } else {
599            *loopCount = mCblk->loopCount;
600        }
601    }
602
603    return NO_ERROR;
604}
605
606status_t AudioTrack::setMarkerPosition(uint32_t marker)
607{
608    if (mCbf == 0) return INVALID_OPERATION;
609
610    mMarkerPosition = marker;
611    mMarkerReached = false;
612
613    return NO_ERROR;
614}
615
616status_t AudioTrack::getMarkerPosition(uint32_t *marker)
617{
618    if (marker == 0) return BAD_VALUE;
619
620    *marker = mMarkerPosition;
621
622    return NO_ERROR;
623}
624
625status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
626{
627    if (mCbf == 0) return INVALID_OPERATION;
628
629    uint32_t curPosition;
630    getPosition(&curPosition);
631    mNewPosition = curPosition + updatePeriod;
632    mUpdatePeriod = updatePeriod;
633
634    return NO_ERROR;
635}
636
637status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod)
638{
639    if (updatePeriod == 0) return BAD_VALUE;
640
641    *updatePeriod = mUpdatePeriod;
642
643    return NO_ERROR;
644}
645
646status_t AudioTrack::setPosition(uint32_t position)
647{
648    AutoMutex lock(mLock);
649
650    if (!stopped_l()) return INVALID_OPERATION;
651
652    Mutex::Autolock _l(mCblk->lock);
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_l()) 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(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        audio_stream_type_t 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       ALOGE("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                    ALOGE("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                ALOGE("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        ALOGE("AudioFlinger could not create track, status: %d", status);
803        return status;
804    }
805    sp<IMemory> cblk = track->getCblk();
806    if (cblk == 0) {
807        ALOGE("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->setSendLevel(mSendLevel);
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    bool 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) {
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                        ALOGW(   "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                            ALOGW("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        ALOGW("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        ALOGE("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 = 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            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) src, toWrite);
1005        } else {
1006            toWrite = audioBuffer.size;
1007            memcpy(audioBuffer.i8, src, toWrite);
1008            src += toWrite;
1009        }
1010        userSize -= toWrite;
1011        written += toWrite;
1012
1013        releaseBuffer(&audioBuffer);
1014    } while (userSize >= frameSz);
1015
1016    return written;
1017}
1018
1019// -------------------------------------------------------------------------
1020
1021bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1022{
1023    Buffer audioBuffer;
1024    uint32_t frames;
1025    size_t writtenSize;
1026
1027    mLock.lock();
1028    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1029    // while we are accessing the cblk
1030    sp <IAudioTrack> audioTrack = mAudioTrack;
1031    sp <IMemory> iMem = mCblkMemory;
1032    audio_track_cblk_t* cblk = mCblk;
1033    bool active = mActive;
1034    mLock.unlock();
1035
1036    // Manage underrun callback
1037    if (active && (cblk->framesAvailable() == cblk->frameCount)) {
1038        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1039        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1040            mCbf(EVENT_UNDERRUN, mUserData, 0);
1041            if (cblk->server == cblk->frameCount) {
1042                mCbf(EVENT_BUFFER_END, mUserData, 0);
1043            }
1044            if (mSharedBuffer != 0) return false;
1045        }
1046    }
1047
1048    // Manage loop end callback
1049    while (mLoopCount > cblk->loopCount) {
1050        int loopCount = -1;
1051        mLoopCount--;
1052        if (mLoopCount >= 0) loopCount = mLoopCount;
1053
1054        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1055    }
1056
1057    // Manage marker callback
1058    if (!mMarkerReached && (mMarkerPosition > 0)) {
1059        if (cblk->server >= mMarkerPosition) {
1060            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1061            mMarkerReached = true;
1062        }
1063    }
1064
1065    // Manage new position callback
1066    if (mUpdatePeriod > 0) {
1067        while (cblk->server >= mNewPosition) {
1068            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1069            mNewPosition += mUpdatePeriod;
1070        }
1071    }
1072
1073    // If Shared buffer is used, no data is requested from client.
1074    if (mSharedBuffer != 0) {
1075        frames = 0;
1076    } else {
1077        frames = mRemainingFrames;
1078    }
1079
1080    int32_t waitCount = -1;
1081    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1082        waitCount = 1;
1083    }
1084
1085    do {
1086
1087        audioBuffer.frameCount = frames;
1088
1089        // Calling obtainBuffer() with a wait count of 1
1090        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1091        // stuck here not being able to handle timed events (position, markers, loops).
1092        status_t err = obtainBuffer(&audioBuffer, waitCount);
1093        if (err < NO_ERROR) {
1094            if (err != TIMED_OUT) {
1095                ALOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1096                return false;
1097            }
1098            break;
1099        }
1100        if (err == status_t(STOPPED)) return false;
1101
1102        // Divide buffer size by 2 to take into account the expansion
1103        // due to 8 to 16 bit conversion: the callback must fill only half
1104        // of the destination buffer
1105        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1106            audioBuffer.size >>= 1;
1107        }
1108
1109        size_t reqSize = audioBuffer.size;
1110        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1111        writtenSize = audioBuffer.size;
1112
1113        // Sanity check on returned size
1114        if (ssize_t(writtenSize) <= 0) {
1115            // The callback is done filling buffers
1116            // Keep this thread going to handle timed events and
1117            // still try to get more data in intervals of WAIT_PERIOD_MS
1118            // but don't just loop and block the CPU, so wait
1119            usleep(WAIT_PERIOD_MS*1000);
1120            break;
1121        }
1122        if (writtenSize > reqSize) writtenSize = reqSize;
1123
1124        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1125            // 8 to 16 bit conversion, note that source and destination are the same address
1126            memcpy_to_i16_from_u8(audioBuffer.i16, (const uint8_t *) audioBuffer.i8, writtenSize);
1127            writtenSize <<= 1;
1128        }
1129
1130        audioBuffer.size = writtenSize;
1131        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1132        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
1133        // 16 bit.
1134        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1135
1136        frames -= audioBuffer.frameCount;
1137
1138        releaseBuffer(&audioBuffer);
1139    }
1140    while (frames);
1141
1142    if (frames == 0) {
1143        mRemainingFrames = mNotificationFramesAct;
1144    } else {
1145        mRemainingFrames = frames;
1146    }
1147    return true;
1148}
1149
1150// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1151// the IAudioTrack and IMemory in case they are recreated here.
1152// If the IAudioTrack is successfully restored, the cblk pointer is updated
1153status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1154{
1155    status_t result;
1156
1157    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1158        ALOGW("dead IAudioTrack, creating a new one from %s TID %d",
1159             fromStart ? "start()" : "obtainBuffer()", gettid());
1160
1161        // signal old cblk condition so that other threads waiting for available buffers stop
1162        // waiting now
1163        cblk->cv.broadcast();
1164        cblk->lock.unlock();
1165
1166        // refresh the audio configuration cache in this process to make sure we get new
1167        // output parameters in getOutput_l() and createTrack_l()
1168        AudioSystem::clearAudioConfigCache();
1169
1170        // if the new IAudioTrack is created, createTrack_l() will modify the
1171        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1172        // It will also delete the strong references on previous IAudioTrack and IMemory
1173        result = createTrack_l(mStreamType,
1174                               cblk->sampleRate,
1175                               mFormat,
1176                               mChannelMask,
1177                               mFrameCount,
1178                               mFlags,
1179                               mSharedBuffer,
1180                               getOutput_l(),
1181                               false);
1182
1183        if (result == NO_ERROR) {
1184            uint32_t user = cblk->user;
1185            uint32_t server = cblk->server;
1186            // restore write index and set other indexes to reflect empty buffer status
1187            mCblk->user = user;
1188            mCblk->server = user;
1189            mCblk->userBase = user;
1190            mCblk->serverBase = user;
1191            // restore loop: this is not guaranteed to succeed if new frame count is not
1192            // compatible with loop length
1193            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1194            if (!fromStart) {
1195                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1196                // Make sure that a client relying on callback events indicating underrun or
1197                // the actual amount of audio frames played (e.g SoundPool) receives them.
1198                if (mSharedBuffer == 0) {
1199                    uint32_t frames = 0;
1200                    if (user > server) {
1201                        frames = ((user - server) > mCblk->frameCount) ?
1202                                mCblk->frameCount : (user - server);
1203                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1204                    }
1205                    // restart playback even if buffer is not completely filled.
1206                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1207                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1208                    // the client
1209                    mCblk->stepUser(frames);
1210                }
1211            }
1212            if (mActive) {
1213                result = mAudioTrack->start();
1214                ALOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1215            }
1216            if (fromStart && result == NO_ERROR) {
1217                mNewPosition = mCblk->server + mUpdatePeriod;
1218            }
1219        }
1220        if (result != NO_ERROR) {
1221            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1222            ALOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1223        }
1224        mRestoreStatus = result;
1225        // signal old cblk condition for other threads waiting for restore completion
1226        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1227        cblk->cv.broadcast();
1228    } else {
1229        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1230            ALOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1231            mLock.unlock();
1232            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1233            if (result == NO_ERROR) {
1234                result = mRestoreStatus;
1235            }
1236            cblk->lock.unlock();
1237            mLock.lock();
1238        } else {
1239            ALOGW("dead IAudioTrack, already restored TID %d", gettid());
1240            result = mRestoreStatus;
1241            cblk->lock.unlock();
1242        }
1243    }
1244    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1245         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1246
1247    if (result == NO_ERROR) {
1248        // from now on we switch to the newly created cblk
1249        cblk = mCblk;
1250    }
1251    cblk->lock.lock();
1252
1253    ALOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1254
1255    return result;
1256}
1257
1258status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1259{
1260
1261    const size_t SIZE = 256;
1262    char buffer[SIZE];
1263    String8 result;
1264
1265    result.append(" AudioTrack::dump\n");
1266    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1267    result.append(buffer);
1268    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1269    result.append(buffer);
1270    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1271    result.append(buffer);
1272    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1273    result.append(buffer);
1274    ::write(fd, result.string(), result.size());
1275    return NO_ERROR;
1276}
1277
1278// =========================================================================
1279
1280AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1281    : Thread(bCanCallJava), mReceiver(receiver)
1282{
1283}
1284
1285bool AudioTrack::AudioTrackThread::threadLoop()
1286{
1287    return mReceiver.processAudioBuffer(this);
1288}
1289
1290status_t AudioTrack::AudioTrackThread::readyToRun()
1291{
1292    return NO_ERROR;
1293}
1294
1295void AudioTrack::AudioTrackThread::onFirstRef()
1296{
1297}
1298
1299// =========================================================================
1300
1301
1302audio_track_cblk_t::audio_track_cblk_t()
1303    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1304    userBase(0), serverBase(0), buffers(0), frameCount(0),
1305    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), volumeLR(0),
1306    mSendLevel(0), flags(0)
1307{
1308}
1309
1310uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1311{
1312    uint32_t u = user;
1313
1314    u += frameCount;
1315    // Ensure that user is never ahead of server for AudioRecord
1316    if (flags & CBLK_DIRECTION_MSK) {
1317        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1318        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1319            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1320        }
1321    } else if (u > server) {
1322        ALOGW("stepServer occurred after track reset");
1323        u = server;
1324    }
1325
1326    if (u >= userBase + this->frameCount) {
1327        userBase += this->frameCount;
1328    }
1329
1330    user = u;
1331
1332    // Clear flow control error condition as new data has been written/read to/from buffer.
1333    if (flags & CBLK_UNDERRUN_MSK) {
1334        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1335    }
1336
1337    return u;
1338}
1339
1340bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1341{
1342    if (!tryLock()) {
1343        ALOGW("stepServer() could not lock cblk");
1344        return false;
1345    }
1346
1347    uint32_t s = server;
1348
1349    s += frameCount;
1350    if (flags & CBLK_DIRECTION_MSK) {
1351        // Mark that we have read the first buffer so that next time stepUser() is called
1352        // we switch to normal obtainBuffer() timeout period
1353        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1354            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1355        }
1356        // It is possible that we receive a flush()
1357        // while the mixer is processing a block: in this case,
1358        // stepServer() is called After the flush() has reset u & s and
1359        // we have s > u
1360        if (s > user) {
1361            ALOGW("stepServer occurred after track reset");
1362            s = user;
1363        }
1364    }
1365
1366    if (s >= loopEnd) {
1367        ALOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1368        s = loopStart;
1369        if (--loopCount == 0) {
1370            loopEnd = UINT_MAX;
1371            loopStart = UINT_MAX;
1372        }
1373    }
1374    if (s >= serverBase + this->frameCount) {
1375        serverBase += this->frameCount;
1376    }
1377
1378    server = s;
1379
1380    if (!(flags & CBLK_INVALID_MSK)) {
1381        cv.signal();
1382    }
1383    lock.unlock();
1384    return true;
1385}
1386
1387void* audio_track_cblk_t::buffer(uint32_t offset) const
1388{
1389    return (int8_t *)buffers + (offset - userBase) * frameSize;
1390}
1391
1392uint32_t audio_track_cblk_t::framesAvailable()
1393{
1394    Mutex::Autolock _l(lock);
1395    return framesAvailable_l();
1396}
1397
1398uint32_t audio_track_cblk_t::framesAvailable_l()
1399{
1400    uint32_t u = user;
1401    uint32_t s = server;
1402
1403    if (flags & CBLK_DIRECTION_MSK) {
1404        uint32_t limit = (s < loopStart) ? s : loopStart;
1405        return limit + frameCount - u;
1406    } else {
1407        return frameCount + u - s;
1408    }
1409}
1410
1411uint32_t audio_track_cblk_t::framesReady()
1412{
1413    uint32_t u = user;
1414    uint32_t s = server;
1415
1416    if (flags & CBLK_DIRECTION_MSK) {
1417        if (u < loopEnd) {
1418            return u - s;
1419        } else {
1420            // do not block on mutex shared with client on AudioFlinger side
1421            if (!tryLock()) {
1422                ALOGW("framesReady() could not lock cblk");
1423                return 0;
1424            }
1425            uint32_t frames = UINT_MAX;
1426            if (loopCount >= 0) {
1427                frames = (loopEnd - loopStart)*loopCount + u - s;
1428            }
1429            lock.unlock();
1430            return frames;
1431        }
1432    } else {
1433        return s - u;
1434    }
1435}
1436
1437bool audio_track_cblk_t::tryLock()
1438{
1439    // the code below simulates lock-with-timeout
1440    // we MUST do this to protect the AudioFlinger server
1441    // as this lock is shared with the client.
1442    status_t err;
1443
1444    err = lock.tryLock();
1445    if (err == -EBUSY) { // just wait a bit
1446        usleep(1000);
1447        err = lock.tryLock();
1448    }
1449    if (err != NO_ERROR) {
1450        // probably, the client just died.
1451        return false;
1452    }
1453    return true;
1454}
1455
1456// -------------------------------------------------------------------------
1457
1458}; // namespace android
1459