nsAudioAvailableEventManager.h

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 * The Original Code is Mozilla code.
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 *  Yury Delendik
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#ifndef nsAudioAvailableEventManager_h__
#define nsAudioAvailableEventManager_h__

#include "nsCOMPtr.h"
#include "nsIRunnable.h"
#include "nsBuiltinDecoder.h"
#include "nsBuiltinDecoderReader.h"

using namespace mozilla;

class nsAudioAvailableEventManager
{
public:
  nsAudioAvailableEventManager(nsBuiltinDecoder* aDecoder);
  ~nsAudioAvailableEventManager();

  // Initialize the event manager with audio metadata.  Called before
  // audio begins to get queued or events are dispatched.
  void Init(PRUint32 aChannels, PRUint32 aRate);

  // Dispatch pending MozAudioAvailable events in the queue.  Called
  // from the state machine thread.
  void DispatchPendingEvents(PRUint64 aCurrentTime);

  // Queues audio sample data and re-packages it into equal sized
  // framebuffers.  Called from the audio thread.
  void QueueWrittenAudioData(SoundDataValue* aAudioData,
                             PRUint32 aAudioDataLength,
                             PRUint64 aEndTimeSampleOffset);

  // Clears the queue of any existing events.  Called from both the state
  // machine and audio threads.
  void Clear();

  // Fires one last event for any extra samples that didn't fit in a whole
  // framebuffer. This is meant to be called only once when the audio finishes.
  // Called from the state machine thread.
  void Drain(PRUint64 aTime);

  // Sets the size of the signal buffer.
  // Called from the main and the state machine thread.
  void SetSignalBufferLength(PRUint32 aLength);

private:
  // The decoder associated with the event manager.  The event manager shares
  // the same lifetime as the decoder (the decoder holds a reference to the
  // manager).
  nsBuiltinDecoder* mDecoder;

  // The number of samples per second.
  float mSamplesPerSecond;

  // A buffer for audio data to be dispatched in DOM events.
  nsAutoArrayPtr<float> mSignalBuffer;

  // The current size of the signal buffer, may change due to DOM calls.
  PRUint32 mSignalBufferLength;

  // The size of the new signal buffer, may change due to DOM calls.
  PRUint32 mNewSignalBufferLength;

  // The position of the first available item in mSignalBuffer
  PRUint32 mSignalBufferPosition;

  // The MozAudioAvailable events to be dispatched.  This queue is shared
  // between the state machine and audio threads.
  nsTArray< nsCOMPtr<nsIRunnable> > mPendingEvents;

  // ReentrantMonitor for shared access to mPendingEvents queue or
  // buffer length.
  ReentrantMonitor mReentrantMonitor;
};

#endif