1/*
2 * Copyright (C) 2012 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#ifndef _MEDIA_BUFFER_PULLER_H
18#define _MEDIA_BUFFER_PULLER_H
19
20#include <utils/threads.h>
21#include <utils/Vector.h>
22
23
24namespace android {
25
26struct MediaSource;
27struct MediaBuffer;
28
29/*
30 * An object of this class can pull a list of media buffers
31 * from a MediaSource repeatedly. The user can then get the
32 * buffers from that list.
33 */
34struct MediaBufferPuller {
35public:
36    MediaBufferPuller(const sp<MediaSource>& source);
37    ~MediaBufferPuller();
38
39    // Start to build up the list of the buffers.
40    void start();
41
42    // Release the list of the available buffers, and stop
43    // pulling buffers from the MediaSource.
44    void stop();
45
46    // Get a buffer from the list. If there is no buffer available
47    // at the time this method is called, NULL is returned.
48    MediaBuffer* getBufferBlocking();
49
50    // Get a buffer from the list. If there is no buffer available
51    // at the time this method is called, it blocks waiting for
52    // a buffer to become available or until stop() is called.
53    MediaBuffer* getBufferNonBlocking();
54
55    // Add a buffer to the end of the list available media buffers
56    void putBuffer(MediaBuffer* buffer);
57
58    // Check whether the source returned an error or not.
59    bool hasMediaSourceReturnedError() const;
60
61private:
62    static int acquireThreadStart(void* arg);
63    void acquireThreadFunc();
64
65    static int releaseThreadStart(void* arg);
66    void releaseThreadFunc();
67
68    sp<MediaSource> mSource;
69    Vector<MediaBuffer*> mBuffers;
70    Vector<MediaBuffer*> mReleaseBuffers;
71
72    mutable Mutex mLock;
73    Condition mUserCond;     // for the user of this class
74    Condition mAcquireCond;  // for the acquire thread
75    Condition mReleaseCond;  // for the release thread
76
77    bool mAskToStart;      // Asks the threads to start
78    bool mAskToStop;       // Asks the threads to stop
79    bool mAcquireStopped;  // The acquire thread has stopped
80    bool mReleaseStopped;  // The release thread has stopped
81    status_t mSourceError; // Error returned by MediaSource read
82
83    // Don't call me!
84    MediaBufferPuller(const MediaBufferPuller&);
85    MediaBufferPuller& operator=(const MediaBufferPuller&);
86};
87
88}  // namespace android
89
90#endif  // _MEDIA_BUFFER_PULLER_H
91