VideoCaptureManager opens/closes, starts/stops and enumerates video capture devices. VideoCapture...

content/browser/media_stream/video_capture_manager.h

+// 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.
+
+// VideoCaptureManager is used to open/close, start/stop as well as enumerate
+// available video capture devices. All functions are expected to be called from
+// the Browser::IO thread. VideoCaptureManager will open OS dependent instances
+// of VideoCaptureDevice. A device can only be opened once.
+
+#ifndef CONTENT_BROWSER_MEDIA_STREAM_VIDEO_CAPTURE_MANAGER_H_
+#define CONTENT_BROWSER_MEDIA_STREAM_VIDEO_CAPTURE_MANAGER_H_
+
+#include <map>
+
+#include "base/lazy_instance.h"
+#include "base/threading/thread.h"
+#include "content/browser/media_stream/media_stream_provider.h"
+#include "media/video/capture/video_capture_device.h"
+#include "media/video/capture/video_capture_types.h"
+
+namespace media_stream {
+
+// VideoCaptureManager opens/closes and start/stops video capture devices.
+class VideoCaptureManager : public MediaStreamProvider {
+ public:
+  // Calling |Start| of this id will open the first device, even though open has
+  // not been called. This is used to be able to use video capture devices
+  // before MediaStream is implemented in Chrome and WebKit.
+  enum { kStartOpenSessionId = 1 };
+
+  // Called to get a pointer to the singleton
+  static VideoCaptureManager* Get();
+
+  // Implements MediaStreamProvider.
+  virtual bool Register(MediaStreamProviderListener* listener);
+
+  virtual void Unregister();
+
+  virtual void EnumerateDevices();
+
+  virtual MediaCaptureSessionId Open(const MediaCaptureDeviceInfo& device);
+
+  virtual void Close(MediaCaptureSessionId capture_session_id);
+
+  // Functions used to start and stop media flow.
+  // Start allocates the device and no other application can use the device
+  // before Stop is called. Captured video frames will be delivered to
+  // video_capture_receiver.
+  void Start(const media::VideoCaptureParams& capture_params,
+             media::VideoCaptureDevice::EventHandler* video_capture_receiver);
+
+  // Stops capture device referenced by |capture_session_id|. No more frames
+  // will be delivered to the frame receiver, and |stopped_task| will be called.
+  void Stop(const media::VideoCaptureSessionId capture_session_id,
+            Task* stopped_task);
+
+  virtual ~VideoCaptureManager();
+
+  // Used by unit test to make sure a fake device is used instead of a real
+  // video capture device. Due to timing requirements, the function must be
+  // called before EnumerateDevices and Open.
+  void UseFakeDevice();
+  MessageLoop* GetMessageLoop();
+
+ private:
+  friend struct base::DefaultLazyInstanceTraits<VideoCaptureManager>;
+
+  VideoCaptureManager();
+
+  // Called by the public functions, executed on vc_device_thread_.
+  void OnEnumerateDevices();
+  void OnOpen(MediaCaptureSessionId capture_session_id,
+              const MediaCaptureDeviceInfo device);
+  void OnClose(MediaCaptureSessionId capture_session_id);
+  void OnStart(const media::VideoCaptureParams capture_params,
+               media::VideoCaptureDevice::EventHandler* video_capture_receiver);
+  void OnStop(const media::VideoCaptureSessionId capture_session_id,
+              Task* stopped_task);
+
+
+  // Executed on Browser::IO thread to call Listener.
+  void OnOpened(MediaCaptureSessionId capture_session_id);
+  void OnClosed(MediaCaptureSessionId capture_session_id);
+  void OnDevicesEnumerated(const MediaCaptureDevices& devices);
+  void OnError(MediaCaptureSessionId capture_session_id,
+               MediaStreamProviderError error);
+
+  // Executed on vc_device_thread_ to make sure Listener is called from
+  // Browser::IO thread.
+  void PostOnOpened(MediaCaptureSessionId capture_session_id);
+  void PostOnClosed(MediaCaptureSessionId capture_session_id);
+  void PostOnDevicesEnumerated(MediaCaptureDevices devices);
+  void PostOnError(MediaCaptureSessionId capture_session_id,
+                   MediaStreamProviderError error);
+
+  // Helpers
+  void GetAvailableDevices(media::VideoCaptureDevice::Names* device_names);
+  bool DeviceOpened(const media::VideoCaptureDevice::Name& device_name);
+  bool DeviceOpened(const MediaCaptureDeviceInfo& device_info);
+  bool IsOnCaptureDeviceThread() const;
+
+  // Thread for all calls to VideoCaptureDevice
+  base::Thread vc_device_thread_;
+
+  // Only accessed on Browser::IO thread
+  MediaStreamProviderListener* listener_;
+  MediaCaptureSessionId new_capture_session_id_;
+
+  // Only accessed from vc_device_thread_
+  // TODO(mflodman) Change map key type when changing typedef for
+  // MediaCaptureSessionId.
+  typedef std::map<int, media::VideoCaptureDevice*> VideoCaptureDevices;
+  VideoCaptureDevices devices_;
+
+  // Set to true if using fake devices for testing, false by default.
+  bool use_fake_device_;
+
+  DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
+};
+
+}  // namespace media_stream
+
+DISABLE_RUNNABLE_METHOD_REFCOUNT(media_stream::VideoCaptureManager);
+
+#endif  // CONTENT_BROWSER_MEDIA_STREAM_VIDEO_CAPTURE_MANAGER_H_