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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_OFFLINE_AUDIO_DESTINATION_HANDLER_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_OFFLINE_AUDIO_DESTINATION_HANDLER_H_
#include <memory>
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/task/single_thread_task_runner.h"
#include "third_party/blink/renderer/modules/webaudio/audio_buffer.h"
#include "third_party/blink/renderer/modules/webaudio/audio_destination_node.h"
#include "third_party/blink/renderer/modules/webaudio/offline_audio_context.h"
#include "third_party/blink/renderer/platform/scheduler/public/non_main_thread.h"
namespace blink {
class BaseAudioContext;
class AudioBus;
class OfflineAudioContext;
class OfflineAudioDestinationHandler final : public AudioDestinationHandler {
public:
static scoped_refptr<OfflineAudioDestinationHandler> Create(
AudioNode&,
unsigned number_of_channels,
uint32_t frames_to_process,
float sample_rate);
~OfflineAudioDestinationHandler() override;
// AudioHandler
void Dispose() override;
void Initialize() override;
void Uninitialize() override;
// AudioNode
double TailTime() const override { return 0; }
double LatencyTime() const override { return 0; }
OfflineAudioContext* Context() const final;
// AudioDestinationHandler
void StartRendering() override;
void StopRendering() override;
void Pause() override;
void Resume() override;
uint32_t MaxChannelCount() const override;
void PrepareTaskRunnerForWorklet() override {}
void RestartRendering() override;
double SampleRate() const override { return sample_rate_; }
// This is called when rendering of the offline context is started
// which will save the rendered audio data in `render_target`. This
// allows creation of the AudioBuffer when startRendering is called
// instead of when the OfflineAudioContext is created.
void InitializeOfflineRenderThread(AudioBuffer* render_target);
unsigned NumberOfChannels() const { return number_of_channels_; }
bool RequiresTailProcessing() const final { return false; }
private:
OfflineAudioDestinationHandler(AudioNode&,
unsigned number_of_channels,
uint32_t frames_to_process,
float sample_rate);
// Set up the rendering and start. After setting the context up, it will
// eventually call `DoOfflineRendering()`.
void StartOfflineRendering();
// Suspend the rendering loop and notify the main thread to resolve the
// associated promise.
void SuspendOfflineRendering();
// Start the rendering loop.
void DoOfflineRendering();
// Finish the rendering loop and notify the main thread to resolve the
// promise with the rendered buffer.
void FinishOfflineRendering();
// Suspend/completion callbacks for the main thread.
void NotifySuspend(size_t);
void NotifyComplete();
// The offline version of render() method. If the rendering needs to be
// suspended after checking, this stops the rendering and returns true.
// Otherwise, it returns false after rendering one quantum.
bool RenderIfNotSuspended(AudioBus* source_bus,
AudioBus* destination_bus,
uint32_t number_of_frames);
// Prepares a task runner for the rendering based on the operation mode
// (i.e. non-AudioWorklet or AudioWorklet). This is called when the
// rendering restarts such as context.resume() after context.suspend().
// The only possible transition is from the non-AudioWorklet mode to the
// AudioWorklet mode. Once the AudioWorklet mode is activated, the task runner
// from AudioWorkletThread will be used until the rendering is finished.
void PrepareTaskRunnerForRendering();
// For cross-thread posting, this object uses two different targets.
// 1. rendering thread -> main thread: WeakPtr
// When the main thread starts deleting this object, a task posted with
// a WeakPtr from the rendering thread will be cancelled.
// 2. main thread -> rendering thread: scoped_refptr
// `render_thread_` is owned by this object, so it is safe to target with
// `WrapRefCounted()` instead of `GetWeakPtr()`.
base::WeakPtr<OfflineAudioDestinationHandler> GetWeakPtr() {
return weak_factory_.GetWeakPtr();
}
// This AudioHandler renders into this SharedAudioBuffer.
std::unique_ptr<SharedAudioBuffer> shared_render_target_;
// Temporary AudioBus for each render quantum.
scoped_refptr<AudioBus> render_bus_;
// These variables are for counting the number of frames for the current
// progress and the remaining frames to be processed.
size_t frames_processed_ = 0;
uint32_t frames_to_process_;
// This flag is necessary to distinguish the state of the context between
// 'created' and 'suspended'. If this flag is false and the current state
// is 'suspended', it means the context is created and have not started yet.
bool is_rendering_started_ = false;
unsigned number_of_channels_;
float sample_rate_;
// The rendering thread for the non-AudioWorklet mode. For the AudioWorklet
// node, AudioWorkletThread will drive the rendering.
std::unique_ptr<NonMainThread> render_thread_;
scoped_refptr<base::SingleThreadTaskRunner> render_thread_task_runner_;
scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
base::WeakPtrFactory<OfflineAudioDestinationHandler> weak_factory_{this};
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_OFFLINE_AUDIO_DESTINATION_HANDLER_H_
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