fake_audio_consumer.h revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
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/callback_forward.h"
9#include "base/memory/ref_counted.h"
10#include "media/base/media_export.h"
11
12namespace base {
13class SingleThreadTaskRunner;
14}
15
16namespace media {
17class AudioBus;
18class AudioParameters;
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  // |worker_task_runner| is the task runner on which the ReadCB provided to
25  // Start() will be executed on.  This may or may not be the be for the same
26  // thread that invokes the Start/Stop methods.
27  // |params| is used to determine the frequency of callbacks.
28  FakeAudioConsumer(
29      const scoped_refptr<base::SingleThreadTaskRunner>& worker_task_runner,
30      const AudioParameters& params);
31  ~FakeAudioConsumer();
32
33  // Start executing |read_cb| at a regular intervals.  Stop() must be called by
34  // the same thread before destroying FakeAudioConsumer.
35  typedef base::Callback<void(AudioBus* audio_bus)> ReadCB;
36  void Start(const ReadCB& read_cb);
37
38  // Stop executing the ReadCB provided to Start().  Blocks until the worker
39  // loop is not inside a ReadCB invocation.  Safe to call multiple times.  Must
40  // be called on the same thread that called Start().
41  void Stop();
42
43 private:
44  // All state and implementation is kept within this ref-counted class because
45  // cancellation of posted tasks must happen on the worker thread some time
46  // after the call to Stop() (on the main thread) returns.
47  class Worker;
48  const scoped_refptr<Worker> worker_;
49
50  DISALLOW_COPY_AND_ASSIGN(FakeAudioConsumer);
51};
52
53}  // namespace media
54
55#endif  // MEDIA_AUDIO_FAKE_AUDIO_CONSUMER_H_
56