MediaBufferGroup.cpp revision 20111aa043c5f404472bc63b90bc5aad906b1101 
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#undef NDEBUG
21#include <assert.h>
22
23#include <media/stagefright/MediaBuffer.h>
24#include <media/stagefright/MediaBufferGroup.h>
25
26namespace android {
27
28MediaBufferGroup::MediaBufferGroup()
29    : mFirstBuffer(NULL),
30      mLastBuffer(NULL) {
31}
32
33MediaBufferGroup::~MediaBufferGroup() {
34    MediaBuffer *next;
35    for (MediaBuffer *buffer = mFirstBuffer; buffer != NULL;
36         buffer = next) {
37        next = buffer->nextBuffer();
38
39        assert(buffer->refcount() == 0);
40
41        buffer->setObserver(NULL);
42        buffer->release();
43    }
44}
45
46void MediaBufferGroup::add_buffer(MediaBuffer *buffer) {
47    Mutex::Autolock autoLock(mLock);
48
49    buffer->setObserver(this);
50
51    if (mLastBuffer) {
52        mLastBuffer->setNextBuffer(buffer);
53    } else {
54        mFirstBuffer = buffer;
55    }
56
57    mLastBuffer = buffer;
58}
59
60status_t MediaBufferGroup::acquire_buffer(MediaBuffer **out) {
61    Mutex::Autolock autoLock(mLock);
62
63    for (;;) {
64        for (MediaBuffer *buffer = mFirstBuffer;
65             buffer != NULL; buffer = buffer->nextBuffer()) {
66            if (buffer->refcount() == 0) {
67                buffer->add_ref();
68                buffer->reset();
69
70                *out = buffer;
71                goto exit;
72            }
73        }
74
75        // All buffers are in use. Block until one of them is returned to us.
76        mCondition.wait(mLock);
77    }
78
79exit:
80    return OK;
81}
82
83void MediaBufferGroup::signalBufferReturned(MediaBuffer *) {
84    Mutex::Autolock autoLock(mLock);
85    mCondition.signal();
86}
87
88}  // namespace android
89