fake_audio_consumer.h revision 7d4cd473f85ac64c3747c96c277f9e506a0d2246 
1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef MEDIA_AUDIO_FAKE_AUDIO_CONSUMER_H_
6#define MEDIA_AUDIO_FAKE_AUDIO_CONSUMER_H_
7
8#include "base/cancelable_callback.h"
9#include "base/memory/scoped_ptr.h"
10#include "base/time.h"
11#include "media/audio/audio_parameters.h"
12
13namespace base {
14class MessageLoopProxy;
15}
16
17namespace media {
18class AudioBus;
19
20// A fake audio consumer.  Using a provided message loop, FakeAudioConsumer will
21// simulate a real time consumer of audio data.
22class MEDIA_EXPORT FakeAudioConsumer {
23 public:
24  // |message_loop| is the loop on which the ReadCB provided to Start() will be
25  // executed on.  |params| is used to determine the frequency of callbacks.
26  FakeAudioConsumer(const scoped_refptr<base::MessageLoopProxy>& message_loop,
27                    const AudioParameters& params);
28  ~FakeAudioConsumer();
29
30  // Start executing |read_cb| at a regular interval.  Must be called on the
31  // message loop provided during construction.  Stop() must be called before
32  // destroying FakeAudioConsumer.
33  typedef base::Callback<void(AudioBus* audio_bus)> ReadCB;
34  void Start(const ReadCB& read_cb);
35
36  // Stop executing the ReadCB provided to Start().  Cancels any outstanding
37  // callbacks.  Safe to call multiple times.  Must be called on the message
38  // loop provided during construction.
39  void Stop();
40
41 private:
42  // Task that regularly calls |read_cb_| according to the playback rate as
43  // determined by the audio parameters given during construction.  Runs on
44  // |message_loop_|.
45  void DoRead();
46
47  scoped_refptr<base::MessageLoopProxy> message_loop_;
48  ReadCB read_cb_;
49  scoped_ptr<AudioBus> audio_bus_;
50  base::TimeDelta buffer_duration_;
51  base::TimeTicks next_read_time_;
52
53  // Used to post delayed tasks to the AudioThread that we can cancel.
54  base::CancelableClosure read_task_cb_;
55
56  DISALLOW_COPY_AND_ASSIGN(FakeAudioConsumer);
57};
58
59}  // namespace media
60
61#endif  // MEDIA_AUDIO_FAKE_AUDIO_CONSUMER_H_
62