media/audio/fake_audio_worker.h

   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_WORKER_H_
   6 #define MEDIA_AUDIO_FAKE_AUDIO_WORKER_H_
   7
   8 #include "base/callback_forward.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "media/base/media_export.h"
  11
  12 namespace base {
  13 class SingleThreadTaskRunner;
  14 }
  15
  16 namespace media {
  17 class AudioBus;
  18 class AudioParameters;
  19
  20 // A fake audio worker.  Using a provided message loop, FakeAudioWorker will
  21 // call back the provided callback like a real audio consumer or producer would.
  22 class MEDIA_EXPORT FakeAudioWorker {
  23  public:
  24   // |worker_task_runner| is the task runner on which the closure 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   FakeAudioWorker(
  29       const scoped_refptr<base::SingleThreadTaskRunner>& worker_task_runner,
  30       const AudioParameters& params);
  31   ~FakeAudioWorker();
  32
  33   // Start executing |worker_cb| at a regular intervals.  Stop() must be called
  34   // by the same thread before destroying FakeAudioWorker.
  35   void Start(const base::Closure& worker_cb);
  36
  37   // Stop executing the closure provided to Start(). Blocks until the worker
  38   // loop is not inside a closure invocation. Safe to call multiple times.
  39   // Must be called on the same thread that called Start().
  40   void Stop();
  41
  42  private:
  43   // All state and implementation is kept within this ref-counted class because
  44   // cancellation of posted tasks must happen on the worker thread some time
  45   // after the call to Stop() (on the main thread) returns.
  46   class Worker;
  47   const scoped_refptr<Worker> worker_;
  48
  49   DISALLOW_COPY_AND_ASSIGN(FakeAudioWorker);
  50 };
  51
  52 }  // namespace media
  53
  54 #endif  // MEDIA_AUDIO_FAKE_AUDIO_WORKER_H_