/*
* Copyright (C) 2010, Google Inc. All rights reserved.
*
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* modification, are permitted provided that the following conditions
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*
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#ifndef AudioNodeOutput_h
#define AudioNodeOutput_h
#include "platform/audio/AudioBus.h"
#include "modules/webaudio/AudioNode.h"
#include "modules/webaudio/AudioParam.h"
#include "wtf/HashSet.h"
#include "wtf/RefPtr.h"
#include "wtf/Vector.h"
namespace WebCore {
class AudioContext;
class AudioNodeInput;
// AudioNodeOutput represents a single output for an AudioNode.
// It may be connected to one or more AudioNodeInputs.
class AudioNodeOutput {
public:
// It's OK to pass 0 for numberOfChannels in which case setNumberOfChannels() must be called later on.
AudioNodeOutput(AudioNode*, unsigned numberOfChannels);
// Can be called from any thread.
AudioNode* node() const { return m_node; }
AudioContext* context() { return m_node->context(); }
// Causes our AudioNode to process if it hasn't already for this render quantum.
// It returns the bus containing the processed audio for this output, returning inPlaceBus if in-place processing was possible.
// Called from context's audio thread.
AudioBus* pull(AudioBus* inPlaceBus, size_t framesToProcess);
// bus() will contain the rendered audio after pull() is called for each rendering time quantum.
// Called from context's audio thread.
AudioBus* bus() const;
// renderingFanOutCount() is the number of AudioNodeInputs that we're connected to during rendering.
// Unlike fanOutCount() it will not change during the course of a render quantum.
unsigned renderingFanOutCount() const;
// Must be called with the context's graph lock.
void disconnectAll();
void setNumberOfChannels(unsigned);
unsigned numberOfChannels() const { return m_numberOfChannels; }
bool isChannelCountKnown() const { return numberOfChannels() > 0; }
bool isConnected() { return fanOutCount() > 0 || paramFanOutCount() > 0; }
// Disable/Enable happens when there are still JavaScript references to a node, but it has otherwise "finished" its work.
// For example, when a note has finished playing. It is kept around, because it may be played again at a later time.
// They must be called with the context's graph lock.
void disable();
void enable();
// updateRenderingState() is called in the audio thread at the start or end of the render quantum to handle any recent changes to the graph state.
// It must be called with the context's graph lock.
void updateRenderingState();
private:
AudioNode* m_node;
friend class AudioNodeInput;
friend class AudioParam;
// These are called from AudioNodeInput.
// They must be called with the context's graph lock.
void addInput(AudioNodeInput*);
void removeInput(AudioNodeInput*);
void addParam(AudioParam*);
void removeParam(AudioParam*);
// fanOutCount() is the number of AudioNodeInputs that we're connected to.
// This method should not be called in audio thread rendering code, instead renderingFanOutCount() should be used.
// It must be called with the context's graph lock.
unsigned fanOutCount();
// Similar to fanOutCount(), paramFanOutCount() is the number of AudioParams that we're connected to.
// This method should not be called in audio thread rendering code, instead renderingParamFanOutCount() should be used.
// It must be called with the context's graph lock.
unsigned paramFanOutCount();
// Must be called with the context's graph lock.
void disconnectAllInputs();
void disconnectAllParams();
// updateInternalBus() updates m_internalBus appropriately for the number of channels.
// It is called in the constructor or in the audio thread with the context's graph lock.
void updateInternalBus();
// Announce to any nodes we're connected to that we changed our channel count for its input.
// It must be called in the audio thread with the context's graph lock.
void propagateChannelCount();
// updateNumberOfChannels() is called in the audio thread at the start or end of the render quantum to pick up channel changes.
// It must be called with the context's graph lock.
void updateNumberOfChannels();
// m_numberOfChannels will only be changed in the audio thread.
// The main thread sets m_desiredNumberOfChannels which will later get picked up in the audio thread in updateNumberOfChannels().
unsigned m_numberOfChannels;
unsigned m_desiredNumberOfChannels;
// m_internalBus and m_inPlaceBus must only be changed in the audio thread with the context's graph lock (or constructor).
RefPtr<AudioBus> m_internalBus;
RefPtr<AudioBus> m_inPlaceBus;
// If m_isInPlace is true, use m_inPlaceBus as the valid AudioBus; If false, use the default m_internalBus.
bool m_isInPlace;
HashSet<AudioNodeInput*> m_inputs;
typedef HashSet<AudioNodeInput*>::iterator InputsIterator;
bool m_isEnabled;
// For the purposes of rendering, keeps track of the number of inputs and AudioParams we're connected to.
// These value should only be changed at the very start or end of the rendering quantum.
unsigned m_renderingFanOutCount;
unsigned m_renderingParamFanOutCount;
HashSet<RefPtr<AudioParam> > m_params;
typedef HashSet<RefPtr<AudioParam> >::iterator ParamsIterator;
};
} // namespace WebCore
#endif // AudioNodeOutput_h