chromium/third_party/blink/renderer/platform/audio/push_pull_fifo.h

// Copyright 2017 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_PLATFORM_AUDIO_PUSH_PULL_FIFO_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_PUSH_PULL_FIFO_H_

#include "base/synchronization/lock.h"
#include "third_party/blink/renderer/platform/audio/audio_bus.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/functional.h"
#include "third_party/blink/renderer/platform/wtf/threading.h"

namespace blink {

// A configuration data container for PushPullFIFO unit test.
struct PushPullFIFOStateForTest { … };

// PushPullFIFO class is an intermediate audio sample storage between
// Blink-WebAudio and the renderer. The renderer's hardware callback buffer size
// varies on the platform, but the WebAudio always renders 128 frames (render
// quantum, RQ) thus FIFO is needed to handle the general case.
//
// Note that this object is concurrently accessed by two threads; WebAudio
// rendering thread (WebThread) in Blink and the audio device thread
// (AudioDeviceThread) from the media renderer. The push/pull operations touch
// most of variables in the class (index_write_, index_read_, frames_available_,
// and fifo_Bus_) so the thread safety must be handled with care.
//
// TODO(hongchan): add a unit test for multi-thread access.
class PLATFORM_EXPORT PushPullFIFO { … };

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_PUSH_PULL_FIFO_H_