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1 /*
2  * Copyright (C) 2009 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_TAG "MediaBufferGroup"
18 #include <utils/Log.h>
19 
20 #include <media/stagefright/foundation/ADebug.h>
21 #include <media/stagefright/MediaBuffer.h>
22 #include <media/stagefright/MediaBufferGroup.h>
23 
24 namespace android {
25 
MediaBufferGroup()26 MediaBufferGroup::MediaBufferGroup()
27     : mFirstBuffer(NULL),
28       mLastBuffer(NULL) {
29 }
30 
~MediaBufferGroup()31 MediaBufferGroup::~MediaBufferGroup() {
32     MediaBuffer *next;
33     for (MediaBuffer *buffer = mFirstBuffer; buffer != NULL;
34          buffer = next) {
35         next = buffer->nextBuffer();
36 
37         CHECK_EQ(buffer->refcount(), 0);
38 
39         buffer->setObserver(NULL);
40         buffer->release();
41     }
42 }
43 
add_buffer(MediaBuffer * buffer)44 void MediaBufferGroup::add_buffer(MediaBuffer *buffer) {
45     Mutex::Autolock autoLock(mLock);
46 
47     buffer->setObserver(this);
48 
49     if (mLastBuffer) {
50         mLastBuffer->setNextBuffer(buffer);
51     } else {
52         mFirstBuffer = buffer;
53     }
54 
55     mLastBuffer = buffer;
56 }
57 
acquire_buffer(MediaBuffer ** out)58 status_t MediaBufferGroup::acquire_buffer(MediaBuffer **out) {
59     Mutex::Autolock autoLock(mLock);
60 
61     for (;;) {
62         for (MediaBuffer *buffer = mFirstBuffer;
63              buffer != NULL; buffer = buffer->nextBuffer()) {
64             if (buffer->refcount() == 0) {
65                 buffer->add_ref();
66                 buffer->reset();
67 
68                 *out = buffer;
69                 goto exit;
70             }
71         }
72 
73         // All buffers are in use. Block until one of them is returned to us.
74         mCondition.wait(mLock);
75     }
76 
77 exit:
78     return OK;
79 }
80 
signalBufferReturned(MediaBuffer *)81 void MediaBufferGroup::signalBufferReturned(MediaBuffer *) {
82     Mutex::Autolock autoLock(mLock);
83     mCondition.signal();
84 }
85 
86 }  // namespace android
87