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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 ScriptProcessorNode_h
#define ScriptProcessorNode_h
#include "base/gtest_prod_util.h"
#include "modules/webaudio/AudioNode.h"
#include "platform/audio/AudioBus.h"
#include "wtf/Forward.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefPtr.h"
#include "wtf/Vector.h"
namespace blink {
class AbstractAudioContext;
class AudioBuffer;
// ScriptProcessorNode is an AudioNode which allows for arbitrary synthesis or processing directly using JavaScript.
// The API allows for a variable number of inputs and outputs, although it must have at least one input or output.
// This basic implementation supports no more than one input and output.
// The "onaudioprocess" attribute is an event listener which will get called periodically with an AudioProcessingEvent which has
// AudioBuffers for each input and output.
class ScriptProcessorHandler final : public AudioHandler {
public:
static PassRefPtr<ScriptProcessorHandler> create(AudioNode&, float sampleRate, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
~ScriptProcessorHandler() override;
// AudioHandler
void process(size_t framesToProcess) override;
void initialize() override;
size_t bufferSize() const { return m_bufferSize; }
void setChannelCount(unsigned long, ExceptionState&) override;
void setChannelCountMode(const String&, ExceptionState&) override;
virtual unsigned numberOfOutputChannels() const { return m_numberOfOutputChannels; }
private:
ScriptProcessorHandler(AudioNode&, float sampleRate, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
double tailTime() const override;
double latencyTime() const override;
void fireProcessEvent(unsigned);
// Double buffering
unsigned doubleBufferIndex() const { return m_doubleBufferIndex; }
void swapBuffers() { m_doubleBufferIndex = 1 - m_doubleBufferIndex; }
unsigned m_doubleBufferIndex;
// These Persistent don't make reference cycles including the owner
// ScriptProcessorNode.
PersistentHeapVector<Member<AudioBuffer>> m_inputBuffers;
PersistentHeapVector<Member<AudioBuffer>> m_outputBuffers;
size_t m_bufferSize;
unsigned m_bufferReadWriteIndex;
unsigned m_numberOfInputChannels;
unsigned m_numberOfOutputChannels;
RefPtr<AudioBus> m_internalInputBus;
// Synchronize process() with fireProcessEvent().
mutable Mutex m_processEventLock;
FRIEND_TEST_ALL_PREFIXES(ScriptProcessorNodeTest, BufferLifetime);
};
class ScriptProcessorNode final : public AudioNode {
DEFINE_WRAPPERTYPEINFO();
public:
// bufferSize must be one of the following values: 256, 512, 1024, 2048,
// 4096, 8192, 16384.
// This value controls how frequently the onaudioprocess event handler is
// called and how many sample-frames need to be processed each call.
// Lower numbers for bufferSize will result in a lower (better)
// latency. Higher numbers will be necessary to avoid audio breakup and
// glitches.
// The value chosen must carefully balance between latency and audio quality.
static ScriptProcessorNode* create(AbstractAudioContext&, float sampleRate, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
DEFINE_ATTRIBUTE_EVENT_LISTENER(audioprocess);
size_t bufferSize() const;
private:
ScriptProcessorNode(AbstractAudioContext&, float sampleRate, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
};
} // namespace blink
#endif // ScriptProcessorNode_h
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