Add an AudioInputController to help with audio recording.

This is similar to the existing AudioOutputController class used for playback.
Also adds a unit test which uses the new fake audio input stream, so this patch is dependant on http://codereview.chromium.org/2909015
TEST=no new user visible change to test, just some backend recording additions which are unused at the moment.
BUG=none

Review URL: http://codereview.chromium.org/2905010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@52617 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 121 insertions, 0 deletions

diff --git a/media/audio/audio_input_controller.h b/media/audio/audio_input_controller.h
new file mode 100644
index 0000000..27b3a54
--- /dev/null
+++ b/media/audio/audio_input_controller.h
@@ -0,0 +1,121 @@
+// Copyright (c) 2010 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/lock.h"
+#include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
+#include "base/thread.h"
+#include "media/audio/audio_io.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 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 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;
+  };
+
+  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,
+      AudioManager::Format format,    // Format of the stream.
+      int channels,                   // Number of channels.
+      int sample_rate,                // Sampling frequency/rate.
+      int bits_per_sample,            // Number of bits per sample.
+      int samples_per_packet);        // Size of the hardware buffer.
+
+  // Starts recording in this audio input stream.
+  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.
+  void Close();
+
+  ///////////////////////////////////////////////////////////////////////////
+  // AudioInputCallback methods.
+  virtual void OnData(AudioInputStream* stream, const uint8* src, uint32 size);
+  virtual void OnClose(AudioInputStream* stream);
+  virtual void OnError(AudioInputStream* stream, int code);
+
+ private:
+  // Internal state of the source.
+  enum State {
+    kEmpty,
+    kCreated,
+    kRecording,
+    kClosed,
+    kError
+  };
+
+  AudioInputController(EventHandler* handler);
+
+  // The following methods are executed on the audio controller thread.
+  void DoCreate(AudioManager::Format format, int channels,
+                int sample_rate, int bits_per_sample,
+                uint32 samples_per_packet);
+  void DoRecord();
+  void DoClose();
+  void DoReportError(int code);
+
+  EventHandler* handler_;
+  AudioInputStream* stream_;
+
+  // |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_;
+
+  Lock lock_;
+
+  // The audio input controller thread that this object runs on.
+  base::Thread thread_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioInputController);
+};
+
+}  // namespace media
+
+#endif  //  MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_