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      1 // Copyright 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_CAST_CAST_ENVIRONMENT_H_
      6 #define MEDIA_CAST_CAST_ENVIRONMENT_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/memory/ref_counted.h"
     10 #include "base/memory/scoped_ptr.h"
     11 #include "base/single_thread_task_runner.h"
     12 #include "base/time/tick_clock.h"
     13 #include "base/time/time.h"
     14 #include "media/cast/logging/logging_defines.h"
     15 #include "media/cast/logging/logging_impl.h"
     16 
     17 namespace media {
     18 namespace cast {
     19 
     20 class CastEnvironment : public base::RefCountedThreadSafe<CastEnvironment> {
     21  public:
     22   // An enumeration of the cast threads.
     23   enum ThreadId {
     24     // The main thread is where the cast system is configured and where timers
     25     // and network IO is performed.
     26     MAIN,
     27     // The audio thread is where all send side audio processing is done,
     28     // primarily encoding / decoding but also re-sampling.
     29     AUDIO,
     30     // The video encoder thread is where the video processing is done.
     31     VIDEO,
     32   };
     33 
     34   CastEnvironment(
     35       scoped_ptr<base::TickClock> clock,
     36       scoped_refptr<base::SingleThreadTaskRunner> main_thread_proxy,
     37       scoped_refptr<base::SingleThreadTaskRunner> audio_thread_proxy,
     38       scoped_refptr<base::SingleThreadTaskRunner> video_thread_proxy);
     39 
     40   // These are the same methods in message_loop.h, but are guaranteed to either
     41   // get posted to the MessageLoop if it's still alive, or be deleted otherwise.
     42   // They return true iff the thread existed and the task was posted.  Note that
     43   // even if the task is posted, there's no guarantee that it will run, since
     44   // the target thread may already have a Quit message in its queue.
     45   bool PostTask(ThreadId identifier,
     46                 const tracked_objects::Location& from_here,
     47                 const base::Closure& task);
     48 
     49   bool PostDelayedTask(ThreadId identifier,
     50                        const tracked_objects::Location& from_here,
     51                        const base::Closure& task,
     52                        base::TimeDelta delay);
     53 
     54   bool CurrentlyOn(ThreadId identifier);
     55 
     56   // All of the media::cast implementation must use this TickClock.
     57   base::TickClock* Clock() const { return clock_.get(); }
     58 
     59   // Logging is not thread safe. Its methods should always be called from the
     60   // main thread.
     61   // TODO(hubbe): Logging should be a thread-safe interface.
     62   LoggingImpl* Logging() const { return logging_.get(); }
     63 
     64   scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner(
     65       ThreadId identifier) const;
     66 
     67   bool HasAudioThread() { return audio_thread_proxy_.get() ? true : false; }
     68 
     69   bool HasVideoThread() { return video_thread_proxy_.get() ? true : false; }
     70 
     71  protected:
     72   virtual ~CastEnvironment();
     73 
     74   // Subclasses may override these.
     75   scoped_refptr<base::SingleThreadTaskRunner> main_thread_proxy_;
     76   scoped_refptr<base::SingleThreadTaskRunner> audio_thread_proxy_;
     77   scoped_refptr<base::SingleThreadTaskRunner> video_thread_proxy_;
     78   scoped_ptr<base::TickClock> clock_;
     79   scoped_ptr<LoggingImpl> logging_;
     80 
     81  private:
     82   friend class base::RefCountedThreadSafe<CastEnvironment>;
     83 
     84   DISALLOW_COPY_AND_ASSIGN(CastEnvironment);
     85 };
     86 
     87 }  // namespace cast
     88 }  // namespace media
     89 
     90 #endif  // MEDIA_CAST_CAST_ENVIRONMENT_H_
     91