[DO NOT SUBMIT] AudioWorklet FS2: audio thread

third_party/WebKit/Source/platform/audio/AudioRenderSink.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef AudioRenderSink_h
+#define AudioRenderSink_h
+
+#include "platform/audio/AudioBus.h"
+#include "platform/audio/AudioIOCallback.h"
+#include "platform/audio/AudioSourceProvider.h"
+#include "public/platform/WebAudioDevice.h"
+#include "public/platform/WebVector.h"
+#include "wtf/Allocator.h"
+#include "wtf/Noncopyable.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+class AudioPullFIFO;
+class SecurityOrigin;
+
+// AudioRenderSink is a platform-level intermediate layer (that is not abstract)
+// between Web Audio graph and the audio stack in Chrome media. The most
+// important role of this class is to respond to the isochronous audio callback
+// from the audio thread.
+class PLATFORM_EXPORT AudioRenderSink : public WebAudioDevice::RenderCallback, public AudioSourceProvider {
+    USING_FAST_MALLOC(AudioRenderSink);
+    WTF_MAKE_NONCOPYABLE(AudioRenderSink);
+
+public:
+    AudioRenderSink(AudioIOCallback&, const String&, unsigned, unsigned, float, const PassRefPtr<SecurityOrigin>&);
+    ~AudioRenderSink() override;
+
+    static PassOwnPtr<AudioRenderSink> create(AudioIOCallback&, const String&, unsigned, unsigned, float, const PassRefPtr<SecurityOrigin>&);
+    static size_t renderQuantumSize();
+    static unsigned audioHardwareBufferSize();
+    static float audioHardwareSampleRate();
+    static unsigned audioHardwareChannelCount();
+
+    virtual void start();
+    virtual void stop();
+
+    // This implements WebAudioDevice::RenderCallback. It is the actual callback
+    // function that is called from the audio stack in an isochronous fashion.
+    //
+    // |source| is for the live input, and |destination| is the final audio
+    // buffer passed to the audio stack.
+    void render(const WebVector<float*>& source, const WebVector<float*>& destination, size_t framesToProcess) override;
+
+    // WIP: Mock-up AudioSourceProvider
+    void provideInput(AudioBus*, size_t numberOfFrames);
+
+    bool isRunning() { return m_isRunning; }
+    size_t callbackBufferSize() const { return m_callbackBufferSize; }
+    float sampleRate() const { return m_sampleRate; }
+    unsigned numberOfOutputChannels() const { return m_numberOfOutputChannels; }
+
+private:
+    bool m_isRunning;
+    size_t m_callbackBufferSize;
+    float m_sampleRate;
+    unsigned m_numberOfOutputChannels;
+
+    // Callback reference of AudioDestinationNode's render function.
+    AudioIOCallback& m_callback;
+
+    // Abstract interface to the actual chromium audio stack.
+    OwnPtr<WebAudioDevice> m_webAudioDevice;
+
+    // Containers for live input and output to the audio stack.
+    RefPtr<AudioBus> m_inputBus;
+    RefPtr<AudioBus> m_outputBus;
+
+    OwnPtr<AudioPullFIFO> m_pullFifo;
+};
+
+} // namespace blink
+
+#endif // AudioRenderSink_h