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1 /*
2  * Copyright 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 //#define LOG_NDEBUG 0
18 #define LOG_TAG "Camera3-BufferManager"
19 #define ATRACE_TAG ATRACE_TAG_CAMERA
20 
21 #include <gui/ISurfaceComposer.h>
22 #include <private/gui/ComposerService.h>
23 #include <utils/Log.h>
24 #include <utils/Trace.h>
25 #include "utils/CameraTraces.h"
26 #include "Camera3BufferManager.h"
27 
28 namespace android {
29 
30 namespace camera3 {
31 
Camera3BufferManager(const sp<IGraphicBufferAlloc> & allocator)32 Camera3BufferManager::Camera3BufferManager(const sp<IGraphicBufferAlloc>& allocator) :
33         mAllocator(allocator) {
34     if (allocator == NULL) {
35         sp<ISurfaceComposer> composer(ComposerService::getComposerService());
36         mAllocator = composer->createGraphicBufferAlloc();
37         if (mAllocator == NULL) {
38             ALOGE("createGraphicBufferAlloc failed");
39         }
40     }
41 }
42 
~Camera3BufferManager()43 Camera3BufferManager::~Camera3BufferManager() {
44 }
45 
registerStream(wp<Camera3OutputStream> & stream,const StreamInfo & streamInfo)46 status_t Camera3BufferManager::registerStream(wp<Camera3OutputStream>& stream,
47         const StreamInfo& streamInfo) {
48     ATRACE_CALL();
49 
50     int streamId = streamInfo.streamId;
51     int streamSetId = streamInfo.streamSetId;
52 
53     if (streamId == CAMERA3_STREAM_ID_INVALID || streamSetId == CAMERA3_STREAM_SET_ID_INVALID) {
54         ALOGE("%s: Stream id (%d) or stream set id (%d) is invalid",
55                 __FUNCTION__, streamId, streamSetId);
56         return BAD_VALUE;
57     }
58     if (streamInfo.totalBufferCount > kMaxBufferCount || streamInfo.totalBufferCount == 0) {
59         ALOGE("%s: Stream id (%d) with stream set id (%d) total buffer count %zu is invalid",
60                 __FUNCTION__, streamId, streamSetId, streamInfo.totalBufferCount);
61         return BAD_VALUE;
62     }
63     if (!streamInfo.isConfigured) {
64         ALOGE("%s: Stream (%d) is not configured", __FUNCTION__, streamId);
65         return BAD_VALUE;
66     }
67 
68     // For Gralloc v1, try to allocate a buffer and see if it is successful, otherwise, stream
69     // buffer sharing for this newly added stream is not supported. For Gralloc v0, we don't
70     // need check this, as the buffers are not really shared between streams, the buffers are
71     // allocated for each stream individually, the allocation failure will be checked in
72     // getBufferForStream() call.
73     if (mGrallocVersion > HARDWARE_DEVICE_API_VERSION(0,1)) {
74         // TODO: To be implemented.
75 
76         // In case allocation fails, return invalid operation
77         return INVALID_OPERATION;
78     }
79 
80     Mutex::Autolock l(mLock);
81     if (mAllocator == NULL) {
82         ALOGE("%s: allocator is NULL, buffer manager is bad state.", __FUNCTION__);
83         return INVALID_OPERATION;
84     }
85 
86     // Check if this stream was registered with different stream set ID, if so, error out.
87     for (size_t i = 0; i < mStreamSetMap.size(); i++) {
88         ssize_t streamIdx = mStreamSetMap[i].streamInfoMap.indexOfKey(streamId);
89         if (streamIdx != NAME_NOT_FOUND &&
90             mStreamSetMap[i].streamInfoMap[streamIdx].streamSetId != streamInfo.streamSetId) {
91             ALOGE("%s: It is illegal to register the same stream id with different stream set",
92                     __FUNCTION__);
93             return BAD_VALUE;
94         }
95     }
96     // Check if there is an existing stream set registered; if not, create one; otherwise, add this
97     // stream info to the existing stream set entry.
98     ssize_t setIdx = mStreamSetMap.indexOfKey(streamSetId);
99     if (setIdx == NAME_NOT_FOUND) {
100         ALOGV("%s: stream set %d is not registered to stream set map yet, create it.",
101                 __FUNCTION__, streamSetId);
102         // Create stream info map, then add to mStreamsetMap.
103         StreamSet newStreamSet;
104         setIdx = mStreamSetMap.add(streamSetId, newStreamSet);
105     }
106     // Update stream set map and water mark.
107     StreamSet& currentStreamSet = mStreamSetMap.editValueAt(setIdx);
108     ssize_t streamIdx = currentStreamSet.streamInfoMap.indexOfKey(streamId);
109     if (streamIdx != NAME_NOT_FOUND) {
110         ALOGW("%s: stream %d was already registered with stream set %d",
111                 __FUNCTION__, streamId, streamSetId);
112         return OK;
113     }
114     currentStreamSet.streamInfoMap.add(streamId, streamInfo);
115     currentStreamSet.handoutBufferCountMap.add(streamId, 0);
116     currentStreamSet.attachedBufferCountMap.add(streamId, 0);
117     mStreamMap.add(streamId, stream);
118 
119     // The max allowed buffer count should be the max of buffer count of each stream inside a stream
120     // set.
121     if (streamInfo.totalBufferCount > currentStreamSet.maxAllowedBufferCount) {
122        currentStreamSet.maxAllowedBufferCount = streamInfo.totalBufferCount;
123     }
124 
125     return OK;
126 }
127 
unregisterStream(int streamId,int streamSetId)128 status_t Camera3BufferManager::unregisterStream(int streamId, int streamSetId) {
129     ATRACE_CALL();
130 
131     Mutex::Autolock l(mLock);
132     ALOGV("%s: unregister stream %d with stream set %d", __FUNCTION__,
133             streamId, streamSetId);
134     if (mAllocator == NULL) {
135         ALOGE("%s: allocator is NULL, buffer manager is bad state.", __FUNCTION__);
136         return INVALID_OPERATION;
137     }
138 
139     if (!checkIfStreamRegisteredLocked(streamId, streamSetId)){
140         ALOGE("%s: stream %d with set id %d wasn't properly registered to this buffer manager!",
141                 __FUNCTION__, streamId, streamSetId);
142         return BAD_VALUE;
143     }
144 
145     // De-list all the buffers associated with this stream first.
146     StreamSet& currentSet = mStreamSetMap.editValueFor(streamSetId);
147     BufferList& freeBufs = currentSet.freeBuffers;
148     BufferCountMap& handOutBufferCounts = currentSet.handoutBufferCountMap;
149     BufferCountMap& attachedBufferCounts = currentSet.attachedBufferCountMap;
150     InfoMap& infoMap = currentSet.streamInfoMap;
151     removeBuffersFromBufferListLocked(freeBufs, streamId);
152     handOutBufferCounts.removeItem(streamId);
153     attachedBufferCounts.removeItem(streamId);
154 
155     // Remove the stream info from info map and recalculate the buffer count water mark.
156     infoMap.removeItem(streamId);
157     currentSet.maxAllowedBufferCount = 0;
158     for (size_t i = 0; i < infoMap.size(); i++) {
159         if (infoMap[i].totalBufferCount > currentSet.maxAllowedBufferCount) {
160             currentSet.maxAllowedBufferCount = infoMap[i].totalBufferCount;
161         }
162     }
163     mStreamMap.removeItem(streamId);
164 
165     // Lazy solution: when a stream is unregistered, the streams will be reconfigured, reset
166     // the water mark and let it grow again.
167     currentSet.allocatedBufferWaterMark = 0;
168 
169     // Remove this stream set if all its streams have been removed.
170     if (freeBufs.size() == 0 && handOutBufferCounts.size() == 0 && infoMap.size() == 0) {
171         mStreamSetMap.removeItem(streamSetId);
172     }
173 
174     return OK;
175 }
176 
getBufferForStream(int streamId,int streamSetId,sp<GraphicBuffer> * gb,int * fenceFd)177 status_t Camera3BufferManager::getBufferForStream(int streamId, int streamSetId,
178         sp<GraphicBuffer>* gb, int* fenceFd) {
179     ATRACE_CALL();
180 
181     Mutex::Autolock l(mLock);
182     ALOGV("%s: get buffer for stream %d with stream set %d", __FUNCTION__,
183             streamId, streamSetId);
184     if (mAllocator == NULL) {
185         ALOGE("%s: allocator is NULL, buffer manager is bad state.", __FUNCTION__);
186         return INVALID_OPERATION;
187     }
188 
189     if (!checkIfStreamRegisteredLocked(streamId, streamSetId)) {
190         ALOGE("%s: stream %d is not registered with stream set %d yet!!!",
191                 __FUNCTION__, streamId, streamSetId);
192         return BAD_VALUE;
193     }
194 
195     StreamSet &streamSet = mStreamSetMap.editValueFor(streamSetId);
196     BufferCountMap& handOutBufferCounts = streamSet.handoutBufferCountMap;
197     size_t& bufferCount = handOutBufferCounts.editValueFor(streamId);
198     if (bufferCount >= streamSet.maxAllowedBufferCount) {
199         ALOGE("%s: bufferCount (%zu) exceeds the max allowed buffer count (%zu) of this stream set",
200                 __FUNCTION__, bufferCount, streamSet.maxAllowedBufferCount);
201         return INVALID_OPERATION;
202     }
203 
204     BufferCountMap& attachedBufferCounts = streamSet.attachedBufferCountMap;
205     size_t& attachedBufferCount = attachedBufferCounts.editValueFor(streamId);
206     if (attachedBufferCount > bufferCount) {
207         // We've already attached more buffers to this stream than we currently have
208         // outstanding, so have the stream just use an already-attached buffer
209         bufferCount++;
210         return ALREADY_EXISTS;
211     }
212     ALOGV("Stream %d set %d: Get buffer for stream: Allocate new", streamId, streamSetId);
213 
214     GraphicBufferEntry buffer =
215             getFirstBufferFromBufferListLocked(streamSet.freeBuffers, streamId);
216 
217     if (mGrallocVersion < HARDWARE_DEVICE_API_VERSION(1,0)) {
218         // Allocate one if there is no free buffer available.
219         if (buffer.graphicBuffer == nullptr) {
220             const StreamInfo& info = streamSet.streamInfoMap.valueFor(streamId);
221             status_t res = OK;
222             buffer.fenceFd = -1;
223             buffer.graphicBuffer = mAllocator->createGraphicBuffer(
224                     info.width, info.height, info.format, info.combinedUsage, &res);
225             ALOGV("%s: allocating a new graphic buffer (%dx%d, format 0x%x) %p with handle %p",
226                     __FUNCTION__, info.width, info.height, info.format,
227                     buffer.graphicBuffer.get(), buffer.graphicBuffer->handle);
228             if (res != OK) {
229                 ALOGE("%s: graphic buffer allocation failed: (error %d %s) ",
230                         __FUNCTION__, res, strerror(-res));
231                 return res;
232             }
233             ALOGV("%s: allocation done", __FUNCTION__);
234         }
235 
236         // Increase the hand-out and attached buffer counts for tracking purposes.
237         bufferCount++;
238         attachedBufferCount++;
239         // Update the water mark to be the max hand-out buffer count + 1. An additional buffer is
240         // added to reduce the chance of buffer allocation during stream steady state, especially
241         // for cases where one stream is active, the other stream may request some buffers randomly.
242         if (bufferCount + 1 > streamSet.allocatedBufferWaterMark) {
243             streamSet.allocatedBufferWaterMark = bufferCount + 1;
244         }
245         *gb = buffer.graphicBuffer;
246         *fenceFd = buffer.fenceFd;
247         ALOGV("%s: get buffer (%p) with handle (%p).",
248                 __FUNCTION__, buffer.graphicBuffer.get(), buffer.graphicBuffer->handle);
249 
250         // Proactively free buffers for other streams if the current number of allocated buffers
251         // exceeds the water mark. This only for Gralloc V1, for V2, this logic can also be handled
252         // in returnBufferForStream() if we want to free buffer more quickly.
253         // TODO: probably should find out all the inactive stream IDs, and free the firstly found
254         // buffers for them.
255         StreamId firstOtherStreamId = CAMERA3_STREAM_ID_INVALID;
256         if (streamSet.streamInfoMap.size() > 1) {
257             bool freeBufferIsAttached = false;
258             for (size_t i = 0; i < streamSet.streamInfoMap.size(); i++) {
259                 firstOtherStreamId = streamSet.streamInfoMap[i].streamId;
260                 if (firstOtherStreamId != streamId) {
261 
262                     size_t otherBufferCount  =
263                             streamSet.handoutBufferCountMap.valueFor(firstOtherStreamId);
264                     size_t otherAttachedBufferCount =
265                             streamSet.attachedBufferCountMap.valueFor(firstOtherStreamId);
266                     if (otherAttachedBufferCount > otherBufferCount) {
267                         freeBufferIsAttached = true;
268                         break;
269                     }
270                     if (hasBufferForStreamLocked(streamSet.freeBuffers, firstOtherStreamId)) {
271                         freeBufferIsAttached = false;
272                         break;
273                     }
274                 }
275                 firstOtherStreamId = CAMERA3_STREAM_ID_INVALID;
276             }
277             if (firstOtherStreamId == CAMERA3_STREAM_ID_INVALID) {
278                 return OK;
279             }
280 
281             // This will drop the reference to one free buffer, which will effectively free one
282             // buffer (from the free buffer list) for the inactive streams.
283             size_t totalAllocatedBufferCount = streamSet.freeBuffers.size();
284             for (size_t i = 0; i < streamSet.attachedBufferCountMap.size(); i++) {
285                 totalAllocatedBufferCount += streamSet.attachedBufferCountMap[i];
286             }
287             if (totalAllocatedBufferCount > streamSet.allocatedBufferWaterMark) {
288                 ALOGV("%s: free a buffer from stream %d", __FUNCTION__, firstOtherStreamId);
289                 if (freeBufferIsAttached) {
290                     ALOGV("Stream %d: Freeing buffer: detach", firstOtherStreamId);
291                     sp<Camera3OutputStream> stream =
292                             mStreamMap.valueFor(firstOtherStreamId).promote();
293                     if (stream == nullptr) {
294                         ALOGE("%s: unable to promote stream %d to detach buffer", __FUNCTION__,
295                                 firstOtherStreamId);
296                         return INVALID_OPERATION;
297                     }
298 
299                     // Detach and then drop the buffer.
300                     //
301                     // Need to unlock because the stream may also be calling
302                     // into the buffer manager in parallel to signal buffer
303                     // release, or acquire a new buffer.
304                     {
305                         mLock.unlock();
306                         sp<GraphicBuffer> buffer;
307                         stream->detachBuffer(&buffer, /*fenceFd*/ nullptr);
308                         mLock.lock();
309                     }
310                     size_t& otherAttachedBufferCount =
311                             streamSet.attachedBufferCountMap.editValueFor(firstOtherStreamId);
312                     otherAttachedBufferCount--;
313                 } else {
314                     // Droppable buffer is in the free buffer list, grab and drop
315                     getFirstBufferFromBufferListLocked(streamSet.freeBuffers, firstOtherStreamId);
316                 }
317             }
318         }
319     } else {
320         // TODO: implement this.
321         return BAD_VALUE;
322     }
323 
324     return OK;
325 }
326 
onBufferReleased(int streamId,int streamSetId)327 status_t Camera3BufferManager::onBufferReleased(int streamId, int streamSetId) {
328     ATRACE_CALL();
329     Mutex::Autolock l(mLock);
330 
331     ALOGV("Stream %d set %d: Buffer released", streamId, streamSetId);
332     if (mAllocator == NULL) {
333         ALOGE("%s: allocator is NULL, buffer manager is bad state.", __FUNCTION__);
334         return INVALID_OPERATION;
335     }
336 
337     if (!checkIfStreamRegisteredLocked(streamId, streamSetId)){
338         ALOGV("%s: signaling buffer release for an already unregistered stream "
339                 "(stream %d with set id %d)", __FUNCTION__, streamId, streamSetId);
340         return OK;
341     }
342 
343     if (mGrallocVersion < HARDWARE_DEVICE_API_VERSION(1,0)) {
344         StreamSet& streamSet = mStreamSetMap.editValueFor(streamSetId);
345         BufferCountMap& handOutBufferCounts = streamSet.handoutBufferCountMap;
346         size_t& bufferCount = handOutBufferCounts.editValueFor(streamId);
347         bufferCount--;
348         ALOGV("%s: Stream %d set %d: Buffer count now %zu", __FUNCTION__, streamId, streamSetId,
349                 bufferCount);
350     } else {
351         // TODO: implement gralloc V1 support
352         return BAD_VALUE;
353     }
354 
355     return OK;
356 }
357 
returnBufferForStream(int streamId,int streamSetId,const sp<GraphicBuffer> & buffer,int fenceFd)358 status_t Camera3BufferManager::returnBufferForStream(int streamId,
359         int streamSetId, const sp<GraphicBuffer>& buffer, int fenceFd) {
360     ATRACE_CALL();
361     Mutex::Autolock l(mLock);
362     ALOGV_IF(buffer != 0, "%s: return buffer (%p) with handle (%p) for stream %d and stream set %d",
363             __FUNCTION__, buffer.get(), buffer->handle, streamId, streamSetId);
364     if (mAllocator == NULL) {
365         ALOGE("%s: allocator is NULL, buffer manager is bad state.", __FUNCTION__);
366         return INVALID_OPERATION;
367     }
368 
369     if (!checkIfStreamRegisteredLocked(streamId, streamSetId)){
370         ALOGV("%s: returning buffer for an already unregistered stream (stream %d with set id %d),"
371                 "buffer will be dropped right away!", __FUNCTION__, streamId, streamSetId);
372         return OK;
373     }
374 
375     if (mGrallocVersion < HARDWARE_DEVICE_API_VERSION(1,0)) {
376         // Add to the freeBuffer list.
377         StreamSet& streamSet = mStreamSetMap.editValueFor(streamSetId);
378         if (buffer != 0) {
379             BufferEntry entry;
380             entry.add(streamId, GraphicBufferEntry(buffer, fenceFd));
381             status_t res = addBufferToBufferListLocked(streamSet.freeBuffers, entry);
382             if (res != OK) {
383                 ALOGE("%s: add buffer to free buffer list failed", __FUNCTION__);
384                 return res;
385             }
386         }
387 
388         // Update the handed out and attached buffer count for this buffer.
389         BufferCountMap& handOutBufferCounts = streamSet.handoutBufferCountMap;
390         size_t& bufferCount = handOutBufferCounts.editValueFor(streamId);
391         bufferCount--;
392         size_t& attachedBufferCount = streamSet.attachedBufferCountMap.editValueFor(streamId);
393         attachedBufferCount--;
394     } else {
395         // TODO: implement this.
396         return BAD_VALUE;
397     }
398 
399     return OK;
400 }
401 
dump(int fd,const Vector<String16> & args) const402 void Camera3BufferManager::dump(int fd, const Vector<String16>& args) const {
403     Mutex::Autolock l(mLock);
404 
405     (void) args;
406     String8 lines;
407     lines.appendFormat("      Total stream sets: %zu\n", mStreamSetMap.size());
408     for (size_t i = 0; i < mStreamSetMap.size(); i++) {
409         lines.appendFormat("        Stream set %d has below streams:\n", mStreamSetMap.keyAt(i));
410         for (size_t j = 0; j < mStreamSetMap[i].streamInfoMap.size(); j++) {
411             lines.appendFormat("          Stream %d\n", mStreamSetMap[i].streamInfoMap[j].streamId);
412         }
413         lines.appendFormat("          Stream set max allowed buffer count: %zu\n",
414                 mStreamSetMap[i].maxAllowedBufferCount);
415         lines.appendFormat("          Stream set buffer count water mark: %zu\n",
416                 mStreamSetMap[i].allocatedBufferWaterMark);
417         lines.appendFormat("          Handout buffer counts:\n");
418         for (size_t m = 0; m < mStreamSetMap[i].handoutBufferCountMap.size(); m++) {
419             int streamId = mStreamSetMap[i].handoutBufferCountMap.keyAt(m);
420             size_t bufferCount = mStreamSetMap[i].handoutBufferCountMap.valueAt(m);
421             lines.appendFormat("            stream id: %d, buffer count: %zu.\n",
422                     streamId, bufferCount);
423         }
424         lines.appendFormat("          Attached buffer counts:\n");
425         for (size_t m = 0; m < mStreamSetMap[i].attachedBufferCountMap.size(); m++) {
426             int streamId = mStreamSetMap[i].attachedBufferCountMap.keyAt(m);
427             size_t bufferCount = mStreamSetMap[i].attachedBufferCountMap.valueAt(m);
428             lines.appendFormat("            stream id: %d, attached buffer count: %zu.\n",
429                     streamId, bufferCount);
430         }
431 
432         lines.appendFormat("          Free buffer count: %zu\n",
433                 mStreamSetMap[i].freeBuffers.size());
434         for (auto& bufEntry : mStreamSetMap[i].freeBuffers) {
435             for (size_t m = 0; m < bufEntry.size(); m++) {
436                 const sp<GraphicBuffer>& buffer = bufEntry.valueAt(m).graphicBuffer;
437                 int streamId = bufEntry.keyAt(m);
438                 lines.appendFormat("            stream id: %d, buffer: %p, handle: %p.\n",
439                         streamId, buffer.get(), buffer->handle);
440             }
441         }
442     }
443     write(fd, lines.string(), lines.size());
444 }
445 
checkIfStreamRegisteredLocked(int streamId,int streamSetId) const446 bool Camera3BufferManager::checkIfStreamRegisteredLocked(int streamId, int streamSetId) const {
447     ssize_t setIdx = mStreamSetMap.indexOfKey(streamSetId);
448     if (setIdx == NAME_NOT_FOUND) {
449         ALOGV("%s: stream set %d is not registered to stream set map yet!",
450                 __FUNCTION__, streamSetId);
451         return false;
452     }
453 
454     ssize_t streamIdx = mStreamSetMap.valueAt(setIdx).streamInfoMap.indexOfKey(streamId);
455     if (streamIdx == NAME_NOT_FOUND) {
456         ALOGV("%s: stream %d is not registered to stream info map yet!", __FUNCTION__, streamId);
457         return false;
458     }
459 
460     size_t bufferWaterMark = mStreamSetMap[setIdx].maxAllowedBufferCount;
461     if (bufferWaterMark == 0 || bufferWaterMark > kMaxBufferCount) {
462         ALOGW("%s: stream %d with stream set %d is not registered correctly to stream set map,"
463                 " as the water mark (%zu) is wrong!",
464                 __FUNCTION__, streamId, streamSetId, bufferWaterMark);
465         return false;
466     }
467 
468     return true;
469 }
470 
addBufferToBufferListLocked(BufferList & bufList,const BufferEntry & buffer)471 status_t Camera3BufferManager::addBufferToBufferListLocked(BufferList& bufList,
472         const BufferEntry& buffer) {
473     // TODO: need add some sanity check here.
474     bufList.push_back(buffer);
475 
476     return OK;
477 }
478 
removeBuffersFromBufferListLocked(BufferList & bufferList,int streamId)479 status_t Camera3BufferManager::removeBuffersFromBufferListLocked(BufferList& bufferList,
480         int streamId) {
481     BufferList::iterator i = bufferList.begin();
482     while (i != bufferList.end()) {
483         ssize_t idx = i->indexOfKey(streamId);
484         if (idx != NAME_NOT_FOUND) {
485             ALOGV("%s: Remove a buffer for stream %d, free buffer total count: %zu",
486                     __FUNCTION__, streamId, bufferList.size());
487             i->removeItem(streamId);
488             if (i->isEmpty()) {
489                 i = bufferList.erase(i);
490             }
491         } else {
492             i++;
493         }
494     }
495 
496     return OK;
497 }
498 
hasBufferForStreamLocked(BufferList & buffers,int streamId)499 bool Camera3BufferManager::hasBufferForStreamLocked(BufferList& buffers, int streamId) {
500     BufferList::iterator i = buffers.begin();
501     while (i != buffers.end()) {
502         ssize_t idx = i->indexOfKey(streamId);
503         if (idx != NAME_NOT_FOUND) {
504             return true;
505         }
506         i++;
507     }
508 
509     return false;
510 }
511 
getFirstBufferFromBufferListLocked(BufferList & buffers,int streamId)512 Camera3BufferManager::GraphicBufferEntry Camera3BufferManager::getFirstBufferFromBufferListLocked(
513         BufferList& buffers, int streamId) {
514     // Try to get the first buffer from the free buffer list if there is one.
515     GraphicBufferEntry entry;
516     BufferList::iterator i = buffers.begin();
517     while (i != buffers.end()) {
518         ssize_t idx = i->indexOfKey(streamId);
519         if (idx != NAME_NOT_FOUND) {
520             entry = GraphicBufferEntry(i->valueAt(idx));
521             i = buffers.erase(i);
522             break;
523         } else {
524             i++;
525         }
526     }
527 
528     ALOGV_IF(entry.graphicBuffer == 0, "%s: Unable to find free buffer for stream %d",
529             __FUNCTION__, streamId);
530     return entry;
531 }
532 
533 } // namespace camera3
534 } // namespace android
535