chromium/media/audio/alsa/alsa_output.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// Creates an output stream based on the ALSA PCM interface.
//
// On device write failure, the stream will move itself to an invalid state.
// No more data will be pulled from the data source, or written to the device.
// All calls to public API functions will either no-op themselves, or return an
// error if possible.  Specifically, If the stream is in an error state, Open()
// will return false, and Start() will call OnError() immediately on the
// provided callback.
//
// If the stream is successfully opened, Close() must be called.  After Close
// has been called, the object should be regarded as deleted and not touched.
//
// AlsaPcmOutputStream is a single threaded class that should only be used from
// the audio thread. When modifying the code in this class, please read the
// threading assumptions at the top of the implementation.

#ifndef MEDIA_AUDIO_ALSA_ALSA_OUTPUT_H_
#define MEDIA_AUDIO_ALSA_ALSA_OUTPUT_H_

#include <alsa/asoundlib.h>
#include <stdint.h>

#include <memory>
#include <string>

#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "base/task/single_thread_task_runner.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "media/audio/audio_io.h"
#include "media/base/audio_parameters.h"

namespace media {

class AlsaWrapper;
class AudioManagerBase;
class ChannelMixer;
class SeekableBuffer;

class MEDIA_EXPORT AlsaPcmOutputStream : public AudioOutputStream { … };

MEDIA_EXPORT std::ostream& operator<<(std::ostream& os,
                                      AlsaPcmOutputStream::InternalState);

}  // namespace media

#endif  // MEDIA_AUDIO_ALSA_ALSA_OUTPUT_H_