/*
* Copyright (C) 2012, 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
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef AudioSummingJunction_h
#define AudioSummingJunction_h
#include "platform/audio/AudioBus.h"
#include "wtf/HashSet.h"
#include "wtf/Vector.h"
namespace WebCore {
class AudioContext;
class AudioNodeOutput;
// An AudioSummingJunction represents a point where zero, one, or more AudioNodeOutputs connect.
class AudioSummingJunction {
public:
explicit AudioSummingJunction(AudioContext*);
virtual ~AudioSummingJunction();
// Can be called from any thread.
AudioContext* context() { return m_context.get(); }
// This must be called whenever we modify m_outputs.
void changedOutputs();
// This copies m_outputs to m_renderingOutputs. Please see comments for these lists below.
// This must be called when we own the context's graph lock in the audio thread at the very start or end of the render quantum.
void updateRenderingState();
// Rendering code accesses its version of the current connections here.
unsigned numberOfRenderingConnections() const { return m_renderingOutputs.size(); }
AudioNodeOutput* renderingOutput(unsigned i) { return m_renderingOutputs[i]; }
bool isConnected() const { return numberOfRenderingConnections() > 0; }
virtual bool canUpdateState() = 0;
virtual void didUpdate() = 0;
protected:
RefPtr<AudioContext> m_context;
// m_outputs contains the AudioNodeOutputs representing current connections which are not disabled.
// The rendering code should never use this directly, but instead uses m_renderingOutputs.
HashSet<AudioNodeOutput*> m_outputs;
// m_renderingOutputs is a copy of m_outputs which will never be modified during the graph rendering on the audio thread.
// This is the list which is used by the rendering code.
// Whenever m_outputs is modified, the context is told so it can later update m_renderingOutputs from m_outputs at a safe time.
// Most of the time, m_renderingOutputs is identical to m_outputs.
Vector<AudioNodeOutput*> m_renderingOutputs;
// m_renderingStateNeedUpdating keeps track if m_outputs is modified.
bool m_renderingStateNeedUpdating;
};
} // namespace WebCore
#endif // AudioSummingJunction_h