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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.
*/
#pragma once
#include "ActiveDOMObject.h"
#include "AudioBus.h"
#include "AudioNode.h"
#include "EventListener.h"
#include "EventTarget.h"
#include <wtf/Forward.h>
#include <wtf/RefPtr.h>
#include <wtf/Vector.h>
namespace WebCore {
class AudioBuffer;
class AudioContext;
class AudioProcessingEvent;
// 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 ScriptProcessorNode final : public AudioNode, public ActiveDOMObject {
WTF_MAKE_ISO_ALLOCATED(ScriptProcessorNode);
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 Ref<ScriptProcessorNode> create(BaseAudioContext&, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
virtual ~ScriptProcessorNode();
const char* activeDOMObjectName() const override { return "ScriptProcessorNode"; }
// AudioNode
void process(size_t framesToProcess) override;
void initialize() override;
void uninitialize() override;
size_t bufferSize() const { return m_bufferSize; }
ExceptionOr<void> setChannelCount(unsigned) final;
ExceptionOr<void> setChannelCountMode(ChannelCountMode) final;
private:
double tailTime() const override;
double latencyTime() const override;
bool requiresTailProcessing() const final;
ScriptProcessorNode(BaseAudioContext&, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
bool virtualHasPendingActivity() const final;
void eventListenersDidChange() final;
void fireProcessEvent(unsigned bufferIndex);
RefPtr<AudioBuffer> createInputBufferForJS(AudioBuffer*) const;
RefPtr<AudioBuffer> createOutputBufferForJS(AudioBuffer&) const;
// Double buffering.
static constexpr unsigned bufferCount = 2;
unsigned bufferIndex() const { return m_bufferIndex; }
void swapBuffers() { m_bufferIndex = (m_bufferIndex + 1) % bufferCount; }
unsigned m_bufferIndex { 0 };
std::array<Lock, bufferCount> m_bufferLocks;
std::array<RefPtr<AudioBuffer>, bufferCount> m_inputBuffers;
std::array<RefPtr<AudioBuffer>, bufferCount> m_outputBuffers;
mutable RefPtr<AudioBuffer> m_cachedInputBufferForJS;
mutable RefPtr<AudioBuffer> m_cachedOutputBufferForJS;
size_t m_bufferSize;
unsigned m_bufferReadWriteIndex { 0 };
unsigned m_numberOfInputChannels;
unsigned m_numberOfOutputChannels;
RefPtr<AudioBus> m_internalInputBus;
bool m_hasAudioProcessEventListener { false };
};
} // namespace WebCore
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