111 lines
4.7 KiB
C++
111 lines
4.7 KiB
C++
/*
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* Copyright (C) 2010 Google Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of Apple Inc. ("Apple") nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef AudioDestination_h
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#define AudioDestination_h
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#include "AudioBus.h"
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#include "AudioIOCallback.h"
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#include <memory>
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#include <wtf/CompletionHandler.h>
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#include <wtf/Lock.h>
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#include <wtf/ThreadSafeRefCounted.h>
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#include <wtf/text/WTFString.h>
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namespace WebCore {
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// AudioDestination is an abstraction for audio hardware I/O.
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// The audio hardware periodically calls the AudioIOCallback render() method asking it to render/output the next render quantum of audio.
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// It optionally will pass in local/live audio input when it calls render().
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class AudioDestination : public ThreadSafeRefCounted<AudioDestination, WTF::DestructionThread::Main> {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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// Pass in (numberOfInputChannels > 0) if live/local audio input is desired.
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// Port-specific device identification information for live/local input streams can be passed in the inputDeviceId.
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WEBCORE_EXPORT static Ref<AudioDestination> create(AudioIOCallback&, const String& inputDeviceId, unsigned numberOfInputChannels, unsigned numberOfOutputChannels, float sampleRate);
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virtual ~AudioDestination() = default;
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void clearCallback();
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virtual void start(Function<void(Function<void()>&&)>&& dispatchToRenderThread, CompletionHandler<void(bool)>&& = [](bool) { }) = 0;
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virtual void stop(CompletionHandler<void(bool)>&& = [](bool) { }) = 0;
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virtual bool isPlaying() = 0;
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// Sample-rate conversion may happen in AudioDestination to the hardware sample-rate
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virtual float sampleRate() const = 0;
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WEBCORE_EXPORT static float hardwareSampleRate();
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virtual unsigned framesPerBuffer() const = 0;
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// maxChannelCount() returns the total number of output channels of the audio hardware.
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// A value of 0 indicates that the number of channels cannot be configured and
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// that only stereo (2-channel) destinations can be created.
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// The numberOfOutputChannels parameter of AudioDestination::create() is allowed to
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// be a value: 1 <= numberOfOutputChannels <= maxChannelCount(),
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// or if maxChannelCount() equals 0, then numberOfOutputChannels must be 2.
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static unsigned long maxChannelCount();
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void callRenderCallback(AudioBus* sourceBus, AudioBus* destinationBus, size_t framesToProcess, const AudioIOPosition& outputPosition);
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protected:
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explicit AudioDestination(AudioIOCallback&);
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Lock m_callbackLock;
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AudioIOCallback* m_callback WTF_GUARDED_BY_LOCK(m_callbackLock) { nullptr };
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};
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inline AudioDestination::AudioDestination(AudioIOCallback& callback)
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{
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Locker locker { m_callbackLock };
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m_callback = &callback;
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}
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inline void AudioDestination::clearCallback()
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{
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Locker locker { m_callbackLock };
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m_callback = nullptr;
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}
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inline void AudioDestination::callRenderCallback(AudioBus* sourceBus, AudioBus* destinationBus, size_t framesToProcess, const AudioIOPosition& outputPosition)
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{
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if (m_callbackLock.tryLock()) {
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Locker locker { AdoptLock, m_callbackLock };
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if (m_callback) {
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m_callback->render(sourceBus, destinationBus, framesToProcess, outputPosition);
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return;
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}
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}
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destinationBus->zero();
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}
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} // namespace WebCore
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#endif // AudioDestination_h
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