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/*
* Copyright (C) 2010, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef AudioNodeOutput_h
#define AudioNodeOutput_h
#include "AudioBus.h"
#include "AudioNode.h"
#include <wtf/HashSet.h>
#include <wtf/OwnPtr.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;
// fanOutCount() is the number of AudioNodeInputs that we're connected to.
// This function 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();
// 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;
// It must be called with the context's graph lock.
void disconnectAllInputs();
void setNumberOfChannels(unsigned);
unsigned numberOfChannels() const { return m_numberOfChannels; }
bool isChannelCountKnown() const { return numberOfChannels() > 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;
// These are called from AudioNodeInput.
// They must be called with the context's graph lock.
void addInput(AudioNodeInput*);
void removeInput(AudioNodeInput*);
// setInternalBus() sets m_internalOutputBus appropriately for the number of channels.
// It is called in the constructor or in the audio thread with the context's graph lock.
void setInternalBus();
// 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_internalOutputBus will point to either m_monoInternalBus or m_stereoInternalBus.
// It must only be changed in the audio thread (or constructor).
AudioBus* m_internalOutputBus;
OwnPtr<AudioBus> m_monoInternalBus;
OwnPtr<AudioBus> m_stereoInternalBus;
// m_actualDestinationBus is set in pull() and will either point to one of our internal busses or to the in-place bus.
// It must only be changed in the audio thread (or constructor).
AudioBus* m_actualDestinationBus;
HashSet<AudioNodeInput*> m_inputs;
typedef HashSet<AudioNodeInput*>::iterator InputsIterator;
bool m_isEnabled;
// For the purposes of rendering, keeps track of the number of inputs we're connected to.
// This value should only be changed at the very start or end of the rendering quantum.
unsigned m_renderingFanOutCount;
};
} // namespace WebCore
#endif // AudioNodeOutput_h
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