media/capture/video/linux/video_capture_device_factory_linux.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.

// Implementation of a VideoCaptureDeviceFactoryLinux class.

#ifndef MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_FACTORY_LINUX_H_
#define MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_FACTORY_LINUX_H_

#include "media/capture/video/video_capture_device_factory.h"

#include <memory>
#include <string>
#include <vector>

#include "base/macros.h"
#include "base/single_thread_task_runner.h"
#include "media/capture/video/linux/v4l2_capture_device.h"
#include "media/capture/video_capture_types.h"

namespace media {

// Extension of VideoCaptureDeviceFactory to create and manipulate Linux
// devices.
class CAPTURE_EXPORT VideoCaptureDeviceFactoryLinux
    : public VideoCaptureDeviceFactory {
 public:
  class CAPTURE_EXPORT DeviceProvider {
   public:
    virtual ~DeviceProvider() {}
    virtual void GetDeviceIds(std::vector<std::string>* target_container) = 0;
    virtual std::string GetDeviceModelId(const std::string& device_id) = 0;
    virtual std::string GetDeviceDisplayName(const std::string& device_id) = 0;
    virtual VideoFacingMode GetCameraFacing(const std::string& device_id,
                                            const std::string& model_id) = 0;
    // Get the orientation of the camera. The value is the angle that the camera
    // image needs to be rotated clockwise so it shows correctly on the display
    // in its natural orientation. It should be 0, 90, 180, or 270.
    //
    // For example, suppose a device has a naturally tall screen. The
    // back-facing camera sensor is mounted in landscape. You are looking at the
    // screen. If the top side of the camera sensor is aligned with the right
    // edge of the screen in natural orientation, the value should be 90. If the
    // top side of a front-facing camera sensor is aligned with the right of the
    // screen, the value should be 270.
    virtual int GetOrientation(const std::string& device_id,
                               const std::string& model_id) = 0;
  };

  explicit VideoCaptureDeviceFactoryLinux(
      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
  ~VideoCaptureDeviceFactoryLinux() override;

  void SetV4L2EnvironmentForTesting(
      scoped_refptr<V4L2CaptureDevice> v4l2,
      std::unique_ptr<DeviceProvider> device_provider);

  std::unique_ptr<VideoCaptureDevice> CreateDevice(
      const VideoCaptureDeviceDescriptor& device_descriptor) override;
  void GetDeviceDescriptors(
      VideoCaptureDeviceDescriptors* device_descriptors) override;
  void GetSupportedFormats(
      const VideoCaptureDeviceDescriptor& device_descriptor,
      VideoCaptureFormats* supported_formats) override;

 private:
  // Simple wrapper to do HANDLE_EINTR(v4l2_->ioctl(fd, ...)).
  int DoIoctl(int fd, int request, void* argp);

  bool HasUsableFormats(int fd, uint32_t capabilities);
  std::vector<float> GetFrameRateList(int fd,
                                      uint32_t fourcc,
                                      uint32_t width,
                                      uint32_t height);
  void GetSupportedFormatsForV4L2BufferType(
      int fd,
      VideoCaptureFormats* supported_formats);

  scoped_refptr<V4L2CaptureDevice> v4l2_;
  std::unique_ptr<DeviceProvider> device_provider_;
  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
  DISALLOW_COPY_AND_ASSIGN(VideoCaptureDeviceFactoryLinux);
};

}  // namespace media
#endif  // MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_FACTORY_LINUX_H_