media/capture/video/video_capture_device_factory.h

// Copyright 2014 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_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_
#define MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_

#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "media/capture/video/video_capture_device.h"

namespace media {

// VideoCaptureDeviceFactory is the base class for creation of video capture
// devices in the different platforms. VCDFs are created by MediaStreamManager
// on IO thread and plugged into VideoCaptureManager, who owns and operates them
// in Device Thread (a.k.a. Audio Thread).
class CAPTURE_EXPORT VideoCaptureDeviceFactory {
 public:
  static std::unique_ptr<VideoCaptureDeviceFactory> CreateFactory(
      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);

  VideoCaptureDeviceFactory();
  virtual ~VideoCaptureDeviceFactory();

  // Creates a VideoCaptureDevice object. Returns NULL if something goes wrong.
  virtual std::unique_ptr<VideoCaptureDevice> Create(
      const VideoCaptureDevice::Name& device_name) = 0;

  // Asynchronous version of GetDeviceNames calling back to |callback|.
  virtual void EnumerateDeviceNames(
      const base::Callback<
          void(std::unique_ptr<media::VideoCaptureDevice::Names>)>& callback);

  // Gets the supported formats of a particular device attached to the system.
  // This method should be called before allocating or starting a device. In
  // case format enumeration is not supported, or there was a problem, the
  // formats array will be empty.
  virtual void GetDeviceSupportedFormats(
      const VideoCaptureDevice::Name& device,
      VideoCaptureFormats* supported_formats) = 0;

 protected:
  // Gets the names of all video capture devices connected to this computer.
  // Used by the default implementation of EnumerateDeviceNames().
  virtual void GetDeviceNames(VideoCaptureDevice::Names* device_names) = 0;

  base::ThreadChecker thread_checker_;

 private:
  static VideoCaptureDeviceFactory* CreateVideoCaptureDeviceFactory(
      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);

  DISALLOW_COPY_AND_ASSIGN(VideoCaptureDeviceFactory);
};

}  // namespace media

#endif  // MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_