Implement Linux audio capturer.

remoting/host/audio_capturer_linux.h

+// Copyright (c) 2012 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 REMOTING_HOST_AUDIO_CAPTURER_LINUX_H_
+#define REMOTING_HOST_AUDIO_CAPTURER_LINUX_H_
+
+#include "remoting/host/audio_capturer.h"
+
+#include "base/message_loop.h"
+#include "base/time.h"
+#include "base/timer.h"
+
+class FilePath;
+
+namespace remoting {
+
+class AudioCapturerLinux : public AudioCapturer,
+                           public MessageLoopForIO::Watcher {
+ public:
+  explicit AudioCapturerLinux(const FilePath& pipe_name);
+  virtual ~AudioCapturerLinux();
+
+  // AudioCapturer interface.
+  virtual bool Start(const PacketCapturedCallback& callback) OVERRIDE;
+  virtual void Stop() OVERRIDE;
+  virtual bool IsRunning() OVERRIDE;

[Wez, 2012/09/06 21:47:29]

nit: IsStarted()

[Sergey Ulanov, 2012/09/06 23:18:53]

Done

+
+  // MessageLoopForIO::Watcher interface.
+  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
+  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE;
+
+ private:
+  void StartTimer();
+  void DoCapture();
+  void Sleep();
+
+  int pipe_fd_;
+  base::RepeatingTimer<AudioCapturerLinux> timer_;
+  PacketCapturedCallback callback_;
+
+  // Time when capturing was started.
+  base::TimeTicks started_time_;
+
+  // Time of the last capture measured in samples relative to the beginning of
+  // the stream.
+  int64 last_capture_time_samples_;

[Wez, 2012/09/06 21:47:29]

Express this simply as the stream position of the latest capture, i.e. no need
to mention time since it's not a time at all.

[Sergey Ulanov, 2012/09/06 23:18:53]

Done
It is time, but measured in number of samples. It doesn't correspond to number
of samples we were actually able to read from the pipe. E.g. if we were read
less than 44100 samples on one particular second, this value is still increased
by 44100.

 

+
+  MessageLoopForIO::FileDescriptorWatcher file_descriptor_watcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioCapturerLinux);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_AUDIO_CAPTURER_LINUX_H_