AudioTrack.cpp revision 2eda60a8485cfe70a60e72156beffdc470ecb093 
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
42#include <system/audio.h>
43#include <system/audio_policy.h>
44
45#define LIKELY( exp )       (__builtin_expect( (exp) != 0, true  ))
46#define UNLIKELY( exp )     (__builtin_expect( (exp) != 0, false ))
47
48namespace android {
49// ---------------------------------------------------------------------------
50
51// static
52status_t AudioTrack::getMinFrameCount(
53        int* frameCount,
54        int 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        int streamType,
89        uint32_t sampleRate,
90        int format,
91        int channelMask,
92        int frameCount,
93        uint32_t flags,
94        callback_t cbf,
95        void* user,
96        int notificationFrames,
97        int sessionId)
98    : mStatus(NO_INIT),
99      mPreviousPriority(ANDROID_PRIORITY_NORMAL), mPreviousSchedulingGroup(ANDROID_TGROUP_DEFAULT)
100{
101    mStatus = set(streamType, sampleRate, format, channelMask,
102            frameCount, flags, cbf, user, notificationFrames,
103            0, false, sessionId);
104}
105
106AudioTrack::AudioTrack(
107        int streamType,
108        uint32_t sampleRate,
109        int format,
110        int channelMask,
111        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        int streamType,
146        uint32_t sampleRate,
147        int 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        LOGE("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 == 0) {
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        LOGE("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        LOGE("Invalid channel mask");
204        return BAD_VALUE;
205    }
206    uint32_t channelCount = popcount(channelMask);
207
208    audio_io_handle_t output = AudioSystem::getOutput(
209                                    (audio_stream_type_t)streamType,
210                                    sampleRate,format, channelMask,
211                                    (audio_policy_output_flags_t)flags);
212
213    if (output == 0) {
214        LOGE("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;
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                                  (uint32_t)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        if (mAudioTrackThread == 0) {
244          LOGE("Could not create callback thread");
245          return NO_INIT;
246        }
247    }
248
249    mStatus = NO_ERROR;
250
251    mStreamType = streamType;
252    mFormat = (uint32_t)format;
253    mChannelMask = (uint32_t)channelMask;
254    mChannelCount = channelCount;
255    mSharedBuffer = sharedBuffer;
256    mMuted = false;
257    mActive = 0;
258    mCbf = cbf;
259    mUserData = user;
260    mLoopCount = 0;
261    mMarkerPosition = 0;
262    mMarkerReached = false;
263    mNewPosition = 0;
264    mUpdatePeriod = 0;
265    mFlushed = false;
266    mFlags = flags;
267    AudioSystem::acquireAudioSessionId(mSessionId);
268    mRestoreStatus = NO_ERROR;
269    return NO_ERROR;
270}
271
272status_t AudioTrack::initCheck() const
273{
274    return mStatus;
275}
276
277// -------------------------------------------------------------------------
278
279uint32_t AudioTrack::latency() const
280{
281    return mLatency;
282}
283
284int AudioTrack::streamType() const
285{
286    return mStreamType;
287}
288
289int AudioTrack::format() const
290{
291    return mFormat;
292}
293
294int AudioTrack::channelCount() const
295{
296    return mChannelCount;
297}
298
299uint32_t AudioTrack::frameCount() const
300{
301    return mCblk->frameCount;
302}
303
304int AudioTrack::frameSize() const
305{
306    if (audio_is_linear_pcm(mFormat)) {
307        return channelCount()*audio_bytes_per_sample(mFormat);
308    } else {
309        return sizeof(uint8_t);
310    }
311}
312
313sp<IMemory>& AudioTrack::sharedBuffer()
314{
315    return mSharedBuffer;
316}
317
318// -------------------------------------------------------------------------
319
320void AudioTrack::start()
321{
322    sp<AudioTrackThread> t = mAudioTrackThread;
323    status_t status = NO_ERROR;
324
325    ALOGV("start %p", this);
326    if (t != 0) {
327        if (t->exitPending()) {
328            if (t->requestExitAndWait() == WOULD_BLOCK) {
329                LOGE("AudioTrack::start called from thread");
330                return;
331            }
332        }
333        t->mLock.lock();
334     }
335
336    AutoMutex lock(mLock);
337    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
338    // while we are accessing the cblk
339    sp <IAudioTrack> audioTrack = mAudioTrack;
340    sp <IMemory> iMem = mCblkMemory;
341    audio_track_cblk_t* cblk = mCblk;
342
343    if (mActive == 0) {
344        mFlushed = false;
345        mActive = 1;
346        mNewPosition = cblk->server + mUpdatePeriod;
347        cblk->lock.lock();
348        cblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
349        cblk->waitTimeMs = 0;
350        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
351        if (t != 0) {
352            t->run("AudioTrackThread", ANDROID_PRIORITY_AUDIO);
353        } else {
354            mPreviousPriority = getpriority(PRIO_PROCESS, 0);
355            mPreviousSchedulingGroup = androidGetThreadSchedulingGroup(0);
356            androidSetThreadPriority(0, ANDROID_PRIORITY_AUDIO);
357        }
358
359        ALOGV("start %p before lock cblk %p", this, mCblk);
360        if (!(cblk->flags & CBLK_INVALID_MSK)) {
361            cblk->lock.unlock();
362            status = mAudioTrack->start();
363            cblk->lock.lock();
364            if (status == DEAD_OBJECT) {
365                android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
366            }
367        }
368        if (cblk->flags & CBLK_INVALID_MSK) {
369            status = restoreTrack_l(cblk, true);
370        }
371        cblk->lock.unlock();
372        if (status != NO_ERROR) {
373            ALOGV("start() failed");
374            mActive = 0;
375            if (t != 0) {
376                t->requestExit();
377            } else {
378                setpriority(PRIO_PROCESS, 0, mPreviousPriority);
379                androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
380            }
381        }
382    }
383
384    if (t != 0) {
385        t->mLock.unlock();
386    }
387}
388
389void AudioTrack::stop()
390{
391    sp<AudioTrackThread> t = mAudioTrackThread;
392
393    ALOGV("stop %p", this);
394    if (t != 0) {
395        t->mLock.lock();
396    }
397
398    AutoMutex lock(mLock);
399    if (mActive == 1) {
400        mActive = 0;
401        mCblk->cv.signal();
402        mAudioTrack->stop();
403        // Cancel loops (If we are in the middle of a loop, playback
404        // would not stop until loopCount reaches 0).
405        setLoop_l(0, 0, 0);
406        // the playback head position will reset to 0, so if a marker is set, we need
407        // to activate it again
408        mMarkerReached = false;
409        // Force flush if a shared buffer is used otherwise audioflinger
410        // will not stop before end of buffer is reached.
411        if (mSharedBuffer != 0) {
412            flush_l();
413        }
414        if (t != 0) {
415            t->requestExit();
416        } else {
417            setpriority(PRIO_PROCESS, 0, mPreviousPriority);
418            androidSetThreadSchedulingGroup(0, mPreviousSchedulingGroup);
419        }
420    }
421
422    if (t != 0) {
423        t->mLock.unlock();
424    }
425}
426
427bool AudioTrack::stopped() const
428{
429    return !mActive;
430}
431
432void AudioTrack::flush()
433{
434    AutoMutex lock(mLock);
435    flush_l();
436}
437
438// must be called with mLock held
439void AudioTrack::flush_l()
440{
441    ALOGV("flush");
442
443    // clear playback marker and periodic update counter
444    mMarkerPosition = 0;
445    mMarkerReached = false;
446    mUpdatePeriod = 0;
447
448    if (!mActive) {
449        mFlushed = true;
450        mAudioTrack->flush();
451        // Release AudioTrack callback thread in case it was waiting for new buffers
452        // in AudioTrack::obtainBuffer()
453        mCblk->cv.signal();
454    }
455}
456
457void AudioTrack::pause()
458{
459    ALOGV("pause");
460    AutoMutex lock(mLock);
461    if (mActive == 1) {
462        mActive = 0;
463        mAudioTrack->pause();
464    }
465}
466
467void AudioTrack::mute(bool e)
468{
469    mAudioTrack->mute(e);
470    mMuted = e;
471}
472
473bool AudioTrack::muted() const
474{
475    return mMuted;
476}
477
478status_t AudioTrack::setVolume(float left, float right)
479{
480    if (left < 0.0f || left > 1.0f || right < 0.0f || right > 1.0f) {
481        return BAD_VALUE;
482    }
483
484    AutoMutex lock(mLock);
485    mVolume[LEFT] = left;
486    mVolume[RIGHT] = right;
487
488    // write must be atomic
489    mCblk->volumeLR = (uint32_t(uint16_t(right * 0x1000)) << 16) | uint16_t(left * 0x1000);
490
491    return NO_ERROR;
492}
493
494void AudioTrack::getVolume(float* left, float* right)
495{
496    if (left != NULL) {
497        *left  = mVolume[LEFT];
498    }
499    if (right != NULL) {
500        *right = mVolume[RIGHT];
501    }
502}
503
504status_t AudioTrack::setAuxEffectSendLevel(float level)
505{
506    ALOGV("setAuxEffectSendLevel(%f)", level);
507    if (level > 1.0f) {
508        return BAD_VALUE;
509    }
510    AutoMutex lock(mLock);
511
512    mSendLevel = level;
513
514    mCblk->sendLevel = uint16_t(level * 0x1000);
515
516    return NO_ERROR;
517}
518
519void AudioTrack::getAuxEffectSendLevel(float* level)
520{
521    if (level != NULL) {
522        *level  = mSendLevel;
523    }
524}
525
526status_t AudioTrack::setSampleRate(int rate)
527{
528    int afSamplingRate;
529
530    if (AudioSystem::getOutputSamplingRate(&afSamplingRate, mStreamType) != NO_ERROR) {
531        return NO_INIT;
532    }
533    // Resampler implementation limits input sampling rate to 2 x output sampling rate.
534    if (rate <= 0 || rate > afSamplingRate*2 ) return BAD_VALUE;
535
536    AutoMutex lock(mLock);
537    mCblk->sampleRate = rate;
538    return NO_ERROR;
539}
540
541uint32_t AudioTrack::getSampleRate()
542{
543    AutoMutex lock(mLock);
544    return mCblk->sampleRate;
545}
546
547status_t AudioTrack::setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount)
548{
549    AutoMutex lock(mLock);
550    return setLoop_l(loopStart, loopEnd, loopCount);
551}
552
553// must be called with mLock held
554status_t AudioTrack::setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount)
555{
556    audio_track_cblk_t* cblk = mCblk;
557
558    Mutex::Autolock _l(cblk->lock);
559
560    if (loopCount == 0) {
561        cblk->loopStart = UINT_MAX;
562        cblk->loopEnd = UINT_MAX;
563        cblk->loopCount = 0;
564        mLoopCount = 0;
565        return NO_ERROR;
566    }
567
568    if (loopStart >= loopEnd ||
569        loopEnd - loopStart > cblk->frameCount ||
570        cblk->server > loopStart) {
571        LOGE("setLoop invalid value: loopStart %d, loopEnd %d, loopCount %d, framecount %d, user %d", loopStart, loopEnd, loopCount, cblk->frameCount, cblk->user);
572        return BAD_VALUE;
573    }
574
575    if ((mSharedBuffer != 0) && (loopEnd > cblk->frameCount)) {
576        LOGE("setLoop invalid value: loop markers beyond data: loopStart %d, loopEnd %d, framecount %d",
577            loopStart, loopEnd, cblk->frameCount);
578        return BAD_VALUE;
579    }
580
581    cblk->loopStart = loopStart;
582    cblk->loopEnd = loopEnd;
583    cblk->loopCount = loopCount;
584    mLoopCount = loopCount;
585
586    return NO_ERROR;
587}
588
589status_t AudioTrack::getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount)
590{
591    AutoMutex lock(mLock);
592    if (loopStart != 0) {
593        *loopStart = mCblk->loopStart;
594    }
595    if (loopEnd != 0) {
596        *loopEnd = mCblk->loopEnd;
597    }
598    if (loopCount != 0) {
599        if (mCblk->loopCount < 0) {
600            *loopCount = -1;
601        } else {
602            *loopCount = mCblk->loopCount;
603        }
604    }
605
606    return NO_ERROR;
607}
608
609status_t AudioTrack::setMarkerPosition(uint32_t marker)
610{
611    if (mCbf == 0) return INVALID_OPERATION;
612
613    mMarkerPosition = marker;
614    mMarkerReached = false;
615
616    return NO_ERROR;
617}
618
619status_t AudioTrack::getMarkerPosition(uint32_t *marker)
620{
621    if (marker == 0) return BAD_VALUE;
622
623    *marker = mMarkerPosition;
624
625    return NO_ERROR;
626}
627
628status_t AudioTrack::setPositionUpdatePeriod(uint32_t updatePeriod)
629{
630    if (mCbf == 0) return INVALID_OPERATION;
631
632    uint32_t curPosition;
633    getPosition(&curPosition);
634    mNewPosition = curPosition + updatePeriod;
635    mUpdatePeriod = updatePeriod;
636
637    return NO_ERROR;
638}
639
640status_t AudioTrack::getPositionUpdatePeriod(uint32_t *updatePeriod)
641{
642    if (updatePeriod == 0) return BAD_VALUE;
643
644    *updatePeriod = mUpdatePeriod;
645
646    return NO_ERROR;
647}
648
649status_t AudioTrack::setPosition(uint32_t position)
650{
651    AutoMutex lock(mLock);
652    Mutex::Autolock _l(mCblk->lock);
653
654    if (!stopped()) return INVALID_OPERATION;
655
656    if (position > mCblk->user) return BAD_VALUE;
657
658    mCblk->server = position;
659    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
660
661    return NO_ERROR;
662}
663
664status_t AudioTrack::getPosition(uint32_t *position)
665{
666    if (position == 0) return BAD_VALUE;
667    AutoMutex lock(mLock);
668    *position = mFlushed ? 0 : mCblk->server;
669
670    return NO_ERROR;
671}
672
673status_t AudioTrack::reload()
674{
675    AutoMutex lock(mLock);
676
677    if (!stopped()) return INVALID_OPERATION;
678
679    flush_l();
680
681    mCblk->stepUser(mCblk->frameCount);
682
683    return NO_ERROR;
684}
685
686audio_io_handle_t AudioTrack::getOutput()
687{
688    AutoMutex lock(mLock);
689    return getOutput_l();
690}
691
692// must be called with mLock held
693audio_io_handle_t AudioTrack::getOutput_l()
694{
695    return AudioSystem::getOutput((audio_stream_type_t)mStreamType,
696            mCblk->sampleRate, mFormat, mChannelMask, (audio_policy_output_flags_t)mFlags);
697}
698
699int AudioTrack::getSessionId()
700{
701    return mSessionId;
702}
703
704status_t AudioTrack::attachAuxEffect(int effectId)
705{
706    ALOGV("attachAuxEffect(%d)", effectId);
707    status_t status = mAudioTrack->attachAuxEffect(effectId);
708    if (status == NO_ERROR) {
709        mAuxEffectId = effectId;
710    }
711    return status;
712}
713
714// -------------------------------------------------------------------------
715
716// must be called with mLock held
717status_t AudioTrack::createTrack_l(
718        int streamType,
719        uint32_t sampleRate,
720        uint32_t format,
721        uint32_t channelMask,
722        int frameCount,
723        uint32_t flags,
724        const sp<IMemory>& sharedBuffer,
725        audio_io_handle_t output,
726        bool enforceFrameCount)
727{
728    status_t status;
729    const sp<IAudioFlinger>& audioFlinger = AudioSystem::get_audio_flinger();
730    if (audioFlinger == 0) {
731       LOGE("Could not get audioflinger");
732       return NO_INIT;
733    }
734
735    int afSampleRate;
736    if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
737        return NO_INIT;
738    }
739    int afFrameCount;
740    if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
741        return NO_INIT;
742    }
743    uint32_t afLatency;
744    if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
745        return NO_INIT;
746    }
747
748    mNotificationFramesAct = mNotificationFramesReq;
749    if (!audio_is_linear_pcm(format)) {
750        if (sharedBuffer != 0) {
751            frameCount = sharedBuffer->size();
752        }
753    } else {
754        // Ensure that buffer depth covers at least audio hardware latency
755        uint32_t minBufCount = afLatency / ((1000 * afFrameCount)/afSampleRate);
756        if (minBufCount < 2) minBufCount = 2;
757
758        int minFrameCount = (afFrameCount*sampleRate*minBufCount)/afSampleRate;
759
760        if (sharedBuffer == 0) {
761            if (frameCount == 0) {
762                frameCount = minFrameCount;
763            }
764            if (mNotificationFramesAct == 0) {
765                mNotificationFramesAct = frameCount/2;
766            }
767            // Make sure that application is notified with sufficient margin
768            // before underrun
769            if (mNotificationFramesAct > (uint32_t)frameCount/2) {
770                mNotificationFramesAct = frameCount/2;
771            }
772            if (frameCount < minFrameCount) {
773                if (enforceFrameCount) {
774                    LOGE("Invalid buffer size: minFrameCount %d, frameCount %d", minFrameCount, frameCount);
775                    return BAD_VALUE;
776                } else {
777                    frameCount = minFrameCount;
778                }
779            }
780        } else {
781            // Ensure that buffer alignment matches channelcount
782            int channelCount = popcount(channelMask);
783            if (((uint32_t)sharedBuffer->pointer() & (channelCount | 1)) != 0) {
784                LOGE("Invalid buffer alignement: address %p, channelCount %d", sharedBuffer->pointer(), channelCount);
785                return BAD_VALUE;
786            }
787            frameCount = sharedBuffer->size()/channelCount/sizeof(int16_t);
788        }
789    }
790
791    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
792                                                      streamType,
793                                                      sampleRate,
794                                                      format,
795                                                      channelMask,
796                                                      frameCount,
797                                                      ((uint16_t)flags) << 16,
798                                                      sharedBuffer,
799                                                      output,
800                                                      &mSessionId,
801                                                      &status);
802
803    if (track == 0) {
804        LOGE("AudioFlinger could not create track, status: %d", status);
805        return status;
806    }
807    sp<IMemory> cblk = track->getCblk();
808    if (cblk == 0) {
809        LOGE("Could not get control block");
810        return NO_INIT;
811    }
812    mAudioTrack = track;
813    mCblkMemory = cblk;
814    mCblk = static_cast<audio_track_cblk_t*>(cblk->pointer());
815    android_atomic_or(CBLK_DIRECTION_OUT, &mCblk->flags);
816    if (sharedBuffer == 0) {
817        mCblk->buffers = (char*)mCblk + sizeof(audio_track_cblk_t);
818    } else {
819        mCblk->buffers = sharedBuffer->pointer();
820         // Force buffer full condition as data is already present in shared memory
821        mCblk->stepUser(mCblk->frameCount);
822    }
823
824    mCblk->volumeLR = (uint32_t(uint16_t(mVolume[RIGHT] * 0x1000)) << 16) | uint16_t(mVolume[LEFT] * 0x1000);
825    mCblk->sendLevel = uint16_t(mSendLevel * 0x1000);
826    mAudioTrack->attachAuxEffect(mAuxEffectId);
827    mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
828    mCblk->waitTimeMs = 0;
829    mRemainingFrames = mNotificationFramesAct;
830    mLatency = afLatency + (1000*mCblk->frameCount) / sampleRate;
831    return NO_ERROR;
832}
833
834status_t AudioTrack::obtainBuffer(Buffer* audioBuffer, int32_t waitCount)
835{
836    AutoMutex lock(mLock);
837    int active;
838    status_t result = NO_ERROR;
839    audio_track_cblk_t* cblk = mCblk;
840    uint32_t framesReq = audioBuffer->frameCount;
841    uint32_t waitTimeMs = (waitCount < 0) ? cblk->bufferTimeoutMs : WAIT_PERIOD_MS;
842
843    audioBuffer->frameCount  = 0;
844    audioBuffer->size = 0;
845
846    uint32_t framesAvail = cblk->framesAvailable();
847
848    cblk->lock.lock();
849    if (cblk->flags & CBLK_INVALID_MSK) {
850        goto create_new_track;
851    }
852    cblk->lock.unlock();
853
854    if (framesAvail == 0) {
855        cblk->lock.lock();
856        goto start_loop_here;
857        while (framesAvail == 0) {
858            active = mActive;
859            if (UNLIKELY(!active)) {
860                ALOGV("Not active and NO_MORE_BUFFERS");
861                cblk->lock.unlock();
862                return NO_MORE_BUFFERS;
863            }
864            if (UNLIKELY(!waitCount)) {
865                cblk->lock.unlock();
866                return WOULD_BLOCK;
867            }
868            if (!(cblk->flags & CBLK_INVALID_MSK)) {
869                mLock.unlock();
870                result = cblk->cv.waitRelative(cblk->lock, milliseconds(waitTimeMs));
871                cblk->lock.unlock();
872                mLock.lock();
873                if (mActive == 0) {
874                    return status_t(STOPPED);
875                }
876                cblk->lock.lock();
877            }
878
879            if (cblk->flags & CBLK_INVALID_MSK) {
880                goto create_new_track;
881            }
882            if (__builtin_expect(result!=NO_ERROR, false)) {
883                cblk->waitTimeMs += waitTimeMs;
884                if (cblk->waitTimeMs >= cblk->bufferTimeoutMs) {
885                    // timing out when a loop has been set and we have already written upto loop end
886                    // is a normal condition: no need to wake AudioFlinger up.
887                    if (cblk->user < cblk->loopEnd) {
888                        LOGW(   "obtainBuffer timed out (is the CPU pegged?) %p "
889                                "user=%08x, server=%08x", this, cblk->user, cblk->server);
890                        //unlock cblk mutex before calling mAudioTrack->start() (see issue #1617140)
891                        cblk->lock.unlock();
892                        result = mAudioTrack->start();
893                        cblk->lock.lock();
894                        if (result == DEAD_OBJECT) {
895                            android_atomic_or(CBLK_INVALID_ON, &cblk->flags);
896create_new_track:
897                            result = restoreTrack_l(cblk, false);
898                        }
899                        if (result != NO_ERROR) {
900                            LOGW("obtainBuffer create Track error %d", result);
901                            cblk->lock.unlock();
902                            return result;
903                        }
904                    }
905                    cblk->waitTimeMs = 0;
906                }
907
908                if (--waitCount == 0) {
909                    cblk->lock.unlock();
910                    return TIMED_OUT;
911                }
912            }
913            // read the server count again
914        start_loop_here:
915            framesAvail = cblk->framesAvailable_l();
916        }
917        cblk->lock.unlock();
918    }
919
920    // restart track if it was disabled by audioflinger due to previous underrun
921    if (mActive && (cblk->flags & CBLK_DISABLED_MSK)) {
922        android_atomic_and(~CBLK_DISABLED_ON, &cblk->flags);
923        LOGW("obtainBuffer() track %p disabled, restarting", this);
924        mAudioTrack->start();
925    }
926
927    cblk->waitTimeMs = 0;
928
929    if (framesReq > framesAvail) {
930        framesReq = framesAvail;
931    }
932
933    uint32_t u = cblk->user;
934    uint32_t bufferEnd = cblk->userBase + cblk->frameCount;
935
936    if (u + framesReq > bufferEnd) {
937        framesReq = bufferEnd - u;
938    }
939
940    audioBuffer->flags = mMuted ? Buffer::MUTE : 0;
941    audioBuffer->channelCount = mChannelCount;
942    audioBuffer->frameCount = framesReq;
943    audioBuffer->size = framesReq * cblk->frameSize;
944    if (audio_is_linear_pcm(mFormat)) {
945        audioBuffer->format = AUDIO_FORMAT_PCM_16_BIT;
946    } else {
947        audioBuffer->format = mFormat;
948    }
949    audioBuffer->raw = (int8_t *)cblk->buffer(u);
950    active = mActive;
951    return active ? status_t(NO_ERROR) : status_t(STOPPED);
952}
953
954void AudioTrack::releaseBuffer(Buffer* audioBuffer)
955{
956    AutoMutex lock(mLock);
957    mCblk->stepUser(audioBuffer->frameCount);
958}
959
960// -------------------------------------------------------------------------
961
962ssize_t AudioTrack::write(const void* buffer, size_t userSize)
963{
964
965    if (mSharedBuffer != 0) return INVALID_OPERATION;
966
967    if (ssize_t(userSize) < 0) {
968        // sanity-check. user is most-likely passing an error code.
969        LOGE("AudioTrack::write(buffer=%p, size=%u (%d)",
970                buffer, userSize, userSize);
971        return BAD_VALUE;
972    }
973
974    ALOGV("write %p: %d bytes, mActive=%d", this, userSize, mActive);
975
976    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
977    // while we are accessing the cblk
978    mLock.lock();
979    sp <IAudioTrack> audioTrack = mAudioTrack;
980    sp <IMemory> iMem = mCblkMemory;
981    mLock.unlock();
982
983    ssize_t written = 0;
984    const int8_t *src = (const int8_t *)buffer;
985    Buffer audioBuffer;
986    size_t frameSz = (size_t)frameSize();
987
988    do {
989        audioBuffer.frameCount = userSize/frameSz;
990
991        // Calling obtainBuffer() with a negative wait count causes
992        // an (almost) infinite wait time.
993        status_t err = obtainBuffer(&audioBuffer, -1);
994        if (err < 0) {
995            // out of buffers, return #bytes written
996            if (err == status_t(NO_MORE_BUFFERS))
997                break;
998            return ssize_t(err);
999        }
1000
1001        size_t toWrite;
1002
1003        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1004            // Divide capacity by 2 to take expansion into account
1005            toWrite = audioBuffer.size>>1;
1006            // 8 to 16 bit conversion
1007            int count = toWrite;
1008            int16_t *dst = (int16_t *)(audioBuffer.i8);
1009            while(count--) {
1010                *dst++ = (int16_t)(*src++^0x80) << 8;
1011            }
1012        } else {
1013            toWrite = audioBuffer.size;
1014            memcpy(audioBuffer.i8, src, toWrite);
1015            src += toWrite;
1016        }
1017        userSize -= toWrite;
1018        written += toWrite;
1019
1020        releaseBuffer(&audioBuffer);
1021    } while (userSize >= frameSz);
1022
1023    return written;
1024}
1025
1026// -------------------------------------------------------------------------
1027
1028bool AudioTrack::processAudioBuffer(const sp<AudioTrackThread>& thread)
1029{
1030    Buffer audioBuffer;
1031    uint32_t frames;
1032    size_t writtenSize;
1033
1034    mLock.lock();
1035    // acquire a strong reference on the IMemory and IAudioTrack so that they cannot be destroyed
1036    // while we are accessing the cblk
1037    sp <IAudioTrack> audioTrack = mAudioTrack;
1038    sp <IMemory> iMem = mCblkMemory;
1039    audio_track_cblk_t* cblk = mCblk;
1040    mLock.unlock();
1041
1042    // Manage underrun callback
1043    if (mActive && (cblk->framesAvailable() == cblk->frameCount)) {
1044        ALOGV("Underrun user: %x, server: %x, flags %04x", cblk->user, cblk->server, cblk->flags);
1045        if (!(android_atomic_or(CBLK_UNDERRUN_ON, &cblk->flags) & CBLK_UNDERRUN_MSK)) {
1046            mCbf(EVENT_UNDERRUN, mUserData, 0);
1047            if (cblk->server == cblk->frameCount) {
1048                mCbf(EVENT_BUFFER_END, mUserData, 0);
1049            }
1050            if (mSharedBuffer != 0) return false;
1051        }
1052    }
1053
1054    // Manage loop end callback
1055    while (mLoopCount > cblk->loopCount) {
1056        int loopCount = -1;
1057        mLoopCount--;
1058        if (mLoopCount >= 0) loopCount = mLoopCount;
1059
1060        mCbf(EVENT_LOOP_END, mUserData, (void *)&loopCount);
1061    }
1062
1063    // Manage marker callback
1064    if (!mMarkerReached && (mMarkerPosition > 0)) {
1065        if (cblk->server >= mMarkerPosition) {
1066            mCbf(EVENT_MARKER, mUserData, (void *)&mMarkerPosition);
1067            mMarkerReached = true;
1068        }
1069    }
1070
1071    // Manage new position callback
1072    if (mUpdatePeriod > 0) {
1073        while (cblk->server >= mNewPosition) {
1074            mCbf(EVENT_NEW_POS, mUserData, (void *)&mNewPosition);
1075            mNewPosition += mUpdatePeriod;
1076        }
1077    }
1078
1079    // If Shared buffer is used, no data is requested from client.
1080    if (mSharedBuffer != 0) {
1081        frames = 0;
1082    } else {
1083        frames = mRemainingFrames;
1084    }
1085
1086    int32_t waitCount = -1;
1087    if (mUpdatePeriod || (!mMarkerReached && mMarkerPosition) || mLoopCount) {
1088        waitCount = 1;
1089    }
1090
1091    do {
1092
1093        audioBuffer.frameCount = frames;
1094
1095        // Calling obtainBuffer() with a wait count of 1
1096        // limits wait time to WAIT_PERIOD_MS. This prevents from being
1097        // stuck here not being able to handle timed events (position, markers, loops).
1098        status_t err = obtainBuffer(&audioBuffer, waitCount);
1099        if (err < NO_ERROR) {
1100            if (err != TIMED_OUT) {
1101                LOGE_IF(err != status_t(NO_MORE_BUFFERS), "Error obtaining an audio buffer, giving up.");
1102                return false;
1103            }
1104            break;
1105        }
1106        if (err == status_t(STOPPED)) return false;
1107
1108        // Divide buffer size by 2 to take into account the expansion
1109        // due to 8 to 16 bit conversion: the callback must fill only half
1110        // of the destination buffer
1111        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1112            audioBuffer.size >>= 1;
1113        }
1114
1115        size_t reqSize = audioBuffer.size;
1116        mCbf(EVENT_MORE_DATA, mUserData, &audioBuffer);
1117        writtenSize = audioBuffer.size;
1118
1119        // Sanity check on returned size
1120        if (ssize_t(writtenSize) <= 0) {
1121            // The callback is done filling buffers
1122            // Keep this thread going to handle timed events and
1123            // still try to get more data in intervals of WAIT_PERIOD_MS
1124            // but don't just loop and block the CPU, so wait
1125            usleep(WAIT_PERIOD_MS*1000);
1126            break;
1127        }
1128        if (writtenSize > reqSize) writtenSize = reqSize;
1129
1130        if (mFormat == AUDIO_FORMAT_PCM_8_BIT && !(mFlags & AUDIO_POLICY_OUTPUT_FLAG_DIRECT)) {
1131            // 8 to 16 bit conversion
1132            const int8_t *src = audioBuffer.i8 + writtenSize-1;
1133            int count = writtenSize;
1134            int16_t *dst = audioBuffer.i16 + writtenSize-1;
1135            while(count--) {
1136                *dst-- = (int16_t)(*src--^0x80) << 8;
1137            }
1138            writtenSize <<= 1;
1139        }
1140
1141        audioBuffer.size = writtenSize;
1142        // NOTE: mCblk->frameSize is not equal to AudioTrack::frameSize() for
1143        // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sampel size of
1144        // 16 bit.
1145        audioBuffer.frameCount = writtenSize/mCblk->frameSize;
1146
1147        frames -= audioBuffer.frameCount;
1148
1149        releaseBuffer(&audioBuffer);
1150    }
1151    while (frames);
1152
1153    if (frames == 0) {
1154        mRemainingFrames = mNotificationFramesAct;
1155    } else {
1156        mRemainingFrames = frames;
1157    }
1158    return true;
1159}
1160
1161// must be called with mLock and cblk.lock held. Callers must also hold strong references on
1162// the IAudioTrack and IMemory in case they are recreated here.
1163// If the IAudioTrack is successfully restored, the cblk pointer is updated
1164status_t AudioTrack::restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart)
1165{
1166    status_t result;
1167
1168    if (!(android_atomic_or(CBLK_RESTORING_ON, &cblk->flags) & CBLK_RESTORING_MSK)) {
1169        LOGW("dead IAudioTrack, creating a new one from %s TID %d",
1170             fromStart ? "start()" : "obtainBuffer()", gettid());
1171
1172        // signal old cblk condition so that other threads waiting for available buffers stop
1173        // waiting now
1174        cblk->cv.broadcast();
1175        cblk->lock.unlock();
1176
1177        // refresh the audio configuration cache in this process to make sure we get new
1178        // output parameters in getOutput_l() and createTrack_l()
1179        AudioSystem::clearAudioConfigCache();
1180
1181        // if the new IAudioTrack is created, createTrack_l() will modify the
1182        // following member variables: mAudioTrack, mCblkMemory and mCblk.
1183        // It will also delete the strong references on previous IAudioTrack and IMemory
1184        result = createTrack_l(mStreamType,
1185                               cblk->sampleRate,
1186                               mFormat,
1187                               mChannelMask,
1188                               mFrameCount,
1189                               mFlags,
1190                               mSharedBuffer,
1191                               getOutput_l(),
1192                               false);
1193
1194        if (result == NO_ERROR) {
1195            uint32_t user = cblk->user;
1196            uint32_t server = cblk->server;
1197            // restore write index and set other indexes to reflect empty buffer status
1198            mCblk->user = user;
1199            mCblk->server = user;
1200            mCblk->userBase = user;
1201            mCblk->serverBase = user;
1202            // restore loop: this is not guaranteed to succeed if new frame count is not
1203            // compatible with loop length
1204            setLoop_l(cblk->loopStart, cblk->loopEnd, cblk->loopCount);
1205            if (!fromStart) {
1206                mCblk->bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1207                // Make sure that a client relying on callback events indicating underrun or
1208                // the actual amount of audio frames played (e.g SoundPool) receives them.
1209                if (mSharedBuffer == 0) {
1210                    uint32_t frames = 0;
1211                    if (user > server) {
1212                        frames = ((user - server) > mCblk->frameCount) ?
1213                                mCblk->frameCount : (user - server);
1214                        memset(mCblk->buffers, 0, frames * mCblk->frameSize);
1215                    }
1216                    // restart playback even if buffer is not completely filled.
1217                    android_atomic_or(CBLK_FORCEREADY_ON, &mCblk->flags);
1218                    // stepUser() clears CBLK_UNDERRUN_ON flag enabling underrun callbacks to
1219                    // the client
1220                    mCblk->stepUser(frames);
1221                }
1222            }
1223            if (mActive) {
1224                result = mAudioTrack->start();
1225                LOGW_IF(result != NO_ERROR, "restoreTrack_l() start() failed status %d", result);
1226            }
1227            if (fromStart && result == NO_ERROR) {
1228                mNewPosition = mCblk->server + mUpdatePeriod;
1229            }
1230        }
1231        if (result != NO_ERROR) {
1232            android_atomic_and(~CBLK_RESTORING_ON, &cblk->flags);
1233            LOGW_IF(result != NO_ERROR, "restoreTrack_l() failed status %d", result);
1234        }
1235        mRestoreStatus = result;
1236        // signal old cblk condition for other threads waiting for restore completion
1237        android_atomic_or(CBLK_RESTORED_ON, &cblk->flags);
1238        cblk->cv.broadcast();
1239    } else {
1240        if (!(cblk->flags & CBLK_RESTORED_MSK)) {
1241            LOGW("dead IAudioTrack, waiting for a new one TID %d", gettid());
1242            mLock.unlock();
1243            result = cblk->cv.waitRelative(cblk->lock, milliseconds(RESTORE_TIMEOUT_MS));
1244            if (result == NO_ERROR) {
1245                result = mRestoreStatus;
1246            }
1247            cblk->lock.unlock();
1248            mLock.lock();
1249        } else {
1250            LOGW("dead IAudioTrack, already restored TID %d", gettid());
1251            result = mRestoreStatus;
1252            cblk->lock.unlock();
1253        }
1254    }
1255    ALOGV("restoreTrack_l() status %d mActive %d cblk %p, old cblk %p flags %08x old flags %08x",
1256         result, mActive, mCblk, cblk, mCblk->flags, cblk->flags);
1257
1258    if (result == NO_ERROR) {
1259        // from now on we switch to the newly created cblk
1260        cblk = mCblk;
1261    }
1262    cblk->lock.lock();
1263
1264    LOGW_IF(result != NO_ERROR, "restoreTrack_l() error %d TID %d", result, gettid());
1265
1266    return result;
1267}
1268
1269status_t AudioTrack::dump(int fd, const Vector<String16>& args) const
1270{
1271
1272    const size_t SIZE = 256;
1273    char buffer[SIZE];
1274    String8 result;
1275
1276    result.append(" AudioTrack::dump\n");
1277    snprintf(buffer, 255, "  stream type(%d), left - right volume(%f, %f)\n", mStreamType, mVolume[0], mVolume[1]);
1278    result.append(buffer);
1279    snprintf(buffer, 255, "  format(%d), channel count(%d), frame count(%d)\n", mFormat, mChannelCount, mCblk->frameCount);
1280    result.append(buffer);
1281    snprintf(buffer, 255, "  sample rate(%d), status(%d), muted(%d)\n", (mCblk == 0) ? 0 : mCblk->sampleRate, mStatus, mMuted);
1282    result.append(buffer);
1283    snprintf(buffer, 255, "  active(%d), latency (%d)\n", mActive, mLatency);
1284    result.append(buffer);
1285    ::write(fd, result.string(), result.size());
1286    return NO_ERROR;
1287}
1288
1289// =========================================================================
1290
1291AudioTrack::AudioTrackThread::AudioTrackThread(AudioTrack& receiver, bool bCanCallJava)
1292    : Thread(bCanCallJava), mReceiver(receiver)
1293{
1294}
1295
1296bool AudioTrack::AudioTrackThread::threadLoop()
1297{
1298    return mReceiver.processAudioBuffer(this);
1299}
1300
1301status_t AudioTrack::AudioTrackThread::readyToRun()
1302{
1303    return NO_ERROR;
1304}
1305
1306void AudioTrack::AudioTrackThread::onFirstRef()
1307{
1308}
1309
1310// =========================================================================
1311
1312
1313audio_track_cblk_t::audio_track_cblk_t()
1314    : lock(Mutex::SHARED), cv(Condition::SHARED), user(0), server(0),
1315    userBase(0), serverBase(0), buffers(0), frameCount(0),
1316    loopStart(UINT_MAX), loopEnd(UINT_MAX), loopCount(0), volumeLR(0),
1317    sendLevel(0), flags(0)
1318{
1319}
1320
1321uint32_t audio_track_cblk_t::stepUser(uint32_t frameCount)
1322{
1323    uint32_t u = user;
1324
1325    u += frameCount;
1326    // Ensure that user is never ahead of server for AudioRecord
1327    if (flags & CBLK_DIRECTION_MSK) {
1328        // If stepServer() has been called once, switch to normal obtainBuffer() timeout period
1329        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS-1) {
1330            bufferTimeoutMs = MAX_RUN_TIMEOUT_MS;
1331        }
1332    } else if (u > server) {
1333        LOGW("stepServer occurred after track reset");
1334        u = server;
1335    }
1336
1337    if (u >= userBase + this->frameCount) {
1338        userBase += this->frameCount;
1339    }
1340
1341    user = u;
1342
1343    // Clear flow control error condition as new data has been written/read to/from buffer.
1344    if (flags & CBLK_UNDERRUN_MSK) {
1345        android_atomic_and(~CBLK_UNDERRUN_MSK, &flags);
1346    }
1347
1348    return u;
1349}
1350
1351bool audio_track_cblk_t::stepServer(uint32_t frameCount)
1352{
1353    if (!tryLock()) {
1354        LOGW("stepServer() could not lock cblk");
1355        return false;
1356    }
1357
1358    uint32_t s = server;
1359
1360    s += frameCount;
1361    if (flags & CBLK_DIRECTION_MSK) {
1362        // Mark that we have read the first buffer so that next time stepUser() is called
1363        // we switch to normal obtainBuffer() timeout period
1364        if (bufferTimeoutMs == MAX_STARTUP_TIMEOUT_MS) {
1365            bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS - 1;
1366        }
1367        // It is possible that we receive a flush()
1368        // while the mixer is processing a block: in this case,
1369        // stepServer() is called After the flush() has reset u & s and
1370        // we have s > u
1371        if (s > user) {
1372            LOGW("stepServer occurred after track reset");
1373            s = user;
1374        }
1375    }
1376
1377    if (s >= loopEnd) {
1378        LOGW_IF(s > loopEnd, "stepServer: s %u > loopEnd %u", s, loopEnd);
1379        s = loopStart;
1380        if (--loopCount == 0) {
1381            loopEnd = UINT_MAX;
1382            loopStart = UINT_MAX;
1383        }
1384    }
1385    if (s >= serverBase + this->frameCount) {
1386        serverBase += this->frameCount;
1387    }
1388
1389    server = s;
1390
1391    if (!(flags & CBLK_INVALID_MSK)) {
1392        cv.signal();
1393    }
1394    lock.unlock();
1395    return true;
1396}
1397
1398void* audio_track_cblk_t::buffer(uint32_t offset) const
1399{
1400    return (int8_t *)buffers + (offset - userBase) * frameSize;
1401}
1402
1403uint32_t audio_track_cblk_t::framesAvailable()
1404{
1405    Mutex::Autolock _l(lock);
1406    return framesAvailable_l();
1407}
1408
1409uint32_t audio_track_cblk_t::framesAvailable_l()
1410{
1411    uint32_t u = user;
1412    uint32_t s = server;
1413
1414    if (flags & CBLK_DIRECTION_MSK) {
1415        uint32_t limit = (s < loopStart) ? s : loopStart;
1416        return limit + frameCount - u;
1417    } else {
1418        return frameCount + u - s;
1419    }
1420}
1421
1422uint32_t audio_track_cblk_t::framesReady()
1423{
1424    uint32_t u = user;
1425    uint32_t s = server;
1426
1427    if (flags & CBLK_DIRECTION_MSK) {
1428        if (u < loopEnd) {
1429            return u - s;
1430        } else {
1431            // do not block on mutex shared with client on AudioFlinger side
1432            if (!tryLock()) {
1433                LOGW("framesReady() could not lock cblk");
1434                return 0;
1435            }
1436            uint32_t frames = UINT_MAX;
1437            if (loopCount >= 0) {
1438                frames = (loopEnd - loopStart)*loopCount + u - s;
1439            }
1440            lock.unlock();
1441            return frames;
1442        }
1443    } else {
1444        return s - u;
1445    }
1446}
1447
1448bool audio_track_cblk_t::tryLock()
1449{
1450    // the code below simulates lock-with-timeout
1451    // we MUST do this to protect the AudioFlinger server
1452    // as this lock is shared with the client.
1453    status_t err;
1454
1455    err = lock.tryLock();
1456    if (err == -EBUSY) { // just wait a bit
1457        usleep(1000);
1458        err = lock.tryLock();
1459    }
1460    if (err != NO_ERROR) {
1461        // probably, the client just died.
1462        return false;
1463    }
1464    return true;
1465}
1466
1467// -------------------------------------------------------------------------
1468
1469}; // namespace android
1470
1471