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// Copyright (c) 2011 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 MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
#define MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread.h"
#include "base/timer.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_manager.h"
// An AudioInputController controls an AudioInputStream and records data
// from this input stream. It has an important function that it executes
// audio operations like record, pause, stop, etc. on a separate thread.
//
// All the public methods of AudioInputController are non-blocking except
// close, the actual operations are performed on the audio input controller
// thread.
//
// Here is a state diagram for the AudioInputController:
//
// .--> [ Closed / Error ] <--.
// | |
// | |
// [ Created ] ----------> [ Recording ]
// ^
// |
// *[ Empty ]
//
// * Initial state
//
namespace media {
class MEDIA_EXPORT AudioInputController
: public base::RefCountedThreadSafe<AudioInputController>,
public AudioInputStream::AudioInputCallback {
public:
// An event handler that receives events from the AudioInputController. The
// following methods are called on the audio input controller thread.
class MEDIA_EXPORT EventHandler {
public:
virtual ~EventHandler() {}
virtual void OnCreated(AudioInputController* controller) = 0;
virtual void OnRecording(AudioInputController* controller) = 0;
virtual void OnError(AudioInputController* controller, int error_code) = 0;
virtual void OnData(AudioInputController* controller, const uint8* data,
uint32 size) = 0;
};
// A synchronous writer interface used by AudioInputController for
// synchronous writing.
class SyncWriter {
public:
virtual ~SyncWriter() {}
// Notify the synchronous writer about the number of bytes in the
// soundcard which has been recorded.
virtual void UpdateRecordedBytes(uint32 bytes) = 0;
// Write certain amount of data from |data|. This method returns
// number of written bytes.
virtual uint32 Write(const void* data, uint32 size) = 0;
// Close this synchronous writer.
virtual void Close() = 0;
};
// AudioInputController::Create uses the currently registered Factory to
// create the AudioInputController. Factory is intended for testing.
class Factory {
public:
virtual AudioInputController* Create(EventHandler* event_handler,
AudioParameters params) = 0;
protected:
virtual ~Factory() {}
};
virtual ~AudioInputController();
// Factory method for creating an AudioInputController.
// If successful, an audio input controller thread is created. The audio
// device will be created on the new thread and when that is done event
// handler will receive a OnCreated() call.
static scoped_refptr<AudioInputController> Create(
EventHandler* event_handler,
const AudioParameters& params);
// Factory method for creating a low latency audio stream.
static scoped_refptr<AudioInputController> CreateLowLatency(
EventHandler* event_handler,
const AudioParameters& params,
// External synchronous reader for audio controller.
SyncWriter* sync_writer);
// Sets the factory used by the static method Create. AudioInputController
// does not take ownership of |factory|. A value of NULL results in an
// AudioInputController being created directly.
static void set_factory_for_testing(Factory* factory) { factory_ = factory; }
AudioInputStream* stream_for_testing() { return stream_; }
// Starts recording in this audio input stream.
virtual void Record();
// Closes the audio input stream and shutdown the audio input controller
// thread. This method returns only after all operations are completed. This
// input controller cannot be used after this method is called.
//
// It is safe to call this method more than once. Calls after the first one
// will have no effect.
virtual void Close();
bool LowLatencyMode() const { return sync_writer_ != NULL; }
///////////////////////////////////////////////////////////////////////////
// AudioInputCallback methods.
virtual void OnData(AudioInputStream* stream, const uint8* src, uint32 size,
uint32 hardware_delay_bytes);
virtual void OnClose(AudioInputStream* stream);
virtual void OnError(AudioInputStream* stream, int code);
protected:
// Internal state of the source.
enum State {
kEmpty,
kCreated,
kRecording,
kClosed,
kError
};
AudioInputController(EventHandler* handler, SyncWriter* sync_writer);
// The following methods are executed on the audio controller thread.
void DoCreate(const AudioParameters& params);
void DoRecord();
void DoClose();
void DoReportError(int code);
void DoReportNoDataError();
void DoResetNoDataTimer();
EventHandler* handler_;
AudioInputStream* stream_;
// |no_data_timer_| is used to call DoReportNoDataError when we stop
// receiving OnData calls without an OnClose call. This can occur when an
// audio input device is unplugged whilst recording on Windows.
// See http://crbug.com/79936 for details.
base::DelayTimer<AudioInputController> no_data_timer_;
// |state_| is written on the audio input controller thread and is read on
// the hardware audio thread. These operations need to be locked. But lock
// is not required for reading on the audio input controller thread.
State state_;
base::Lock lock_;
// The audio input controller thread that this object runs on.
base::Thread thread_;
// SyncWriter is used only in low latency mode for synchronous writing.
SyncWriter* sync_writer_;
static Factory* factory_;
DISALLOW_COPY_AND_ASSIGN(AudioInputController);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
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