media/capture/video/linux/video_capture_device_factory_v4l2.h

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Implementation of a VideoCaptureDeviceFactoryV4L2 class.

#ifndef MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_FACTORY_V4L2_H_
#define MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_FACTORY_V4L2_H_

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

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

#include "base/task/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 VideoCaptureDeviceFactoryV4L2
    : 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;
  };

  explicit VideoCaptureDeviceFactoryV4L2(
      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);

  VideoCaptureDeviceFactoryV4L2(const VideoCaptureDeviceFactoryV4L2&) = delete;
  VideoCaptureDeviceFactoryV4L2& operator=(
      const VideoCaptureDeviceFactoryV4L2&) = delete;

  ~VideoCaptureDeviceFactoryV4L2() override;

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

  VideoCaptureErrorOrDevice CreateDevice(
      const VideoCaptureDeviceDescriptor& device_descriptor) override;
  void GetDevicesInfo(GetDevicesInfoCallback callback) override;

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

  VideoCaptureControlSupport GetControlSupport(int fd);
  bool GetControlSupport(int fd, int control_id);
  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_;
};

}  // namespace media
#endif  // MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_FACTORY_V4L2_H_