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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_DESTINATION_HANDLER_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_DESTINATION_HANDLER_H_
#include <atomic>
#include "base/notreached.h"
#include "third_party/blink/renderer/modules/webaudio/audio_node.h"
namespace blink {
// The AudioDestinationHandler (ADH) is a base class for the rendering backend
// for AudioDestinatioNode. It contains common information required for the
// rendering such as current sample frame, sample rate and maximum channel count
// of the context.
class AudioDestinationHandler : public AudioHandler {
public:
explicit AudioDestinationHandler(AudioNode&);
~AudioDestinationHandler() override;
// The method MUST NOT be invoked when rendering a graph because the
// destination node is a sink. Instead, this node gets pulled by the
// underlying renderer (audio hardware or worker thread).
void Process(uint32_t) final { NOTREACHED(); }
virtual void StartRendering() = 0;
virtual void StopRendering() = 0;
virtual void Pause() = 0;
virtual void Resume() = 0;
// The render thread needs to be changed after Worklet JS code is loaded by
// AudioWorklet. This method ensures the switching of render thread and the
// restart of the context.
virtual void RestartRendering() = 0;
// The worklet thread change can happen when a context/destination is
// suspended. In that case, we prepare the worklet operation but do not start
// running.
virtual void PrepareTaskRunnerForWorklet() = 0;
size_t CurrentSampleFrame() const {
return current_sample_frame_.load(std::memory_order_acquire);
}
double CurrentTime() const { return CurrentSampleFrame() / SampleRate(); }
virtual double SampleRate() const = 0;
virtual uint32_t MaxChannelCount() const = 0;
void ContextDestroyed() { is_execution_context_destroyed_ = true; }
bool IsExecutionContextDestroyed() const {
return is_execution_context_destroyed_;
}
protected:
void AdvanceCurrentSampleFrame(size_t number_of_frames) {
current_sample_frame_.fetch_add(number_of_frames,
std::memory_order_release);
}
private:
// The number of sample frames processed by the destination so far.
std::atomic_size_t current_sample_frame_{0};
// True if the execution context is being destroyed. If this is true, the
// destination node must avoid checking for or accessing the execution
// context.
bool is_execution_context_destroyed_ = false;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_DESTINATION_HANDLER_H_
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