Home | History | Annotate | Download | only in libstagefright 
      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/MediaBuffer.h>
     21 #include <media/stagefright/MediaBufferGroup.h>
     22 #include <media/stagefright/MediaDebug.h>
     23 
     24 namespace android {
     25 
     26 MediaBufferGroup::MediaBufferGroup()
     27     : mFirstBuffer(NULL),
     28       mLastBuffer(NULL) {
     29 }
     30 
     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 
     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 
     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 
     81 void MediaBufferGroup::signalBufferReturned(MediaBuffer *) {
     82     Mutex::Autolock autoLock(mLock);
     83     mCondition.signal();
     84 }
     85 
     86 }  // namespace android
     87