text: // 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.
  
  #include "media/capture/video/fake_video_capture_device_factory.h"
  
  #include "base/command_line.h"
  #include "base/strings/string_number_conversions.h"
  #include "base/strings/string_split.h"
  #include "base/strings/string_tokenizer.h"
  #include "base/strings/string_util.h"
  #include "base/strings/stringprintf.h"
  #include "build/build_config.h"
  #include "media/base/media_switches.h"
  
  namespace {
  
  // Factory has one device by default; I420. If there are more, the second device
  // is of Y16 format while the rest are I420.
  media::VideoPixelFormat GetPixelFormat(const std::string& device_id) {
    return (device_id == "/dev/video1") ? media::PIXEL_FORMAT_Y16
                                        : media::PIXEL_FORMAT_I420;
  }
  }
  
  namespace media {
  
  // Cap the frame rate command line input to reasonable values.
  static const float kFakeCaptureMinFrameRate = 5.0f;
  static const float kFakeCaptureMaxFrameRate = 60.0f;
  // Default rate if none is specified as part of the command line.
  static const float kFakeCaptureDefaultFrameRate = 20.0f;
  // Cap the device count command line input to reasonable values.
  static const int kFakeCaptureMinDeviceCount = 1;
  static const int kFakeCaptureMaxDeviceCount = 10;
  
  FakeVideoCaptureDeviceFactory::FakeVideoCaptureDeviceFactory()
      : number_of_devices_(1),
        fake_vcd_ownership_(FakeVideoCaptureDevice::BufferOwnership::OWN_BUFFERS),
        frame_rate_(kFakeCaptureDefaultFrameRate) {}
  
  std::unique_ptr<VideoCaptureDevice> FakeVideoCaptureDeviceFactory::CreateDevice(
      const VideoCaptureDeviceDescriptor& device_descriptor) {
    DCHECK(thread_checker_.CalledOnValidThread());
  
    if (!command_line_parsed_) {
      ParseCommandLine();
      command_line_parsed_ = true;
    }
  
    for (int n = 0; n < number_of_devices_; ++n) {
      std::string possible_id = base::StringPrintf("/dev/video%d", n);
      if (device_descriptor.device_id.compare(possible_id) == 0) {
        return std::unique_ptr<VideoCaptureDevice>(new FakeVideoCaptureDevice(
            fake_vcd_ownership_, frame_rate_, GetPixelFormat(possible_id)));
      }
    }
    return std::unique_ptr<VideoCaptureDevice>();
  }
  
  void FakeVideoCaptureDeviceFactory::GetDeviceDescriptors(
      VideoCaptureDeviceDescriptors* device_descriptors) {
    DCHECK(thread_checker_.CalledOnValidThread());
    DCHECK(device_descriptors->empty());
  
    if (!command_line_parsed_) {
      ParseCommandLine();
      command_line_parsed_ = true;
    }
  
    for (int n = 0; n < number_of_devices_; ++n) {
      device_descriptors->emplace_back(base::StringPrintf("fake_device_%d", n),
                                       base::StringPrintf("/dev/video%d", n),
  #if defined(OS_LINUX)
                                       VideoCaptureApi::LINUX_V4L2_SINGLE_PLANE
  #elif defined(OS_MACOSX)
                                       VideoCaptureApi::MACOSX_AVFOUNDATION
  #elif defined(OS_WIN)
                                       VideoCaptureApi::WIN_DIRECT_SHOW
  #elif defined(OS_ANDROID)
                                       VideoCaptureApi::ANDROID_API2_LEGACY
  #endif
                                       );
    }
  }
  
  void FakeVideoCaptureDeviceFactory::GetSupportedFormats(
      const VideoCaptureDeviceDescriptor& device_descriptor,
      VideoCaptureFormats* supported_formats) {
    DCHECK(thread_checker_.CalledOnValidThread());
    const gfx::Size supported_sizes[] = {
        gfx::Size(96, 96), gfx::Size(320, 240), gfx::Size(640, 480),
        gfx::Size(1280, 720), gfx::Size(1920, 1080)};
    supported_formats->clear();
    for (const auto& size : supported_sizes) {
      supported_formats->push_back(VideoCaptureFormat(
          size, frame_rate_, GetPixelFormat(device_descriptor.device_id)));
    }
  }
  
  // Optional comma delimited parameters to the command line can specify buffer
  // ownership, device count, and the fake video devices FPS.
  // Examples: "ownership=client, device-count=2, fps=60" "fps=30"
  void FakeVideoCaptureDeviceFactory::ParseCommandLine() {
    const std::string option =
        base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
            switches::kUseFakeDeviceForMediaStream);
    base::StringTokenizer option_tokenizer(option, ", ");
    option_tokenizer.set_quote_chars("\"");
  
    while (option_tokenizer.GetNext()) {
      std::vector<std::string> param =
          base::SplitString(option_tokenizer.token(), "=", base::TRIM_WHITESPACE,
                            base::SPLIT_WANT_NONEMPTY);
  
      if (param.size() != 2u) {
        LOG(WARNING) << "Forget a value '" << option << "'? Use name=value for "
                     << switches::kUseFakeDeviceForMediaStream << ".";
        return;
      }
  
      if (base::EqualsCaseInsensitiveASCII(param.front(), "ownership") &&
          base::EqualsCaseInsensitiveASCII(param.back(), "client")) {
        fake_vcd_ownership_ =
            FakeVideoCaptureDevice::BufferOwnership::CLIENT_BUFFERS;
      } else if (base::EqualsCaseInsensitiveASCII(param.front(), "fps")) {
        double fps = 0;
        if (base::StringToDouble(param.back(), &fps)) {
          frame_rate_ =
              std::max(kFakeCaptureMinFrameRate, static_cast<float>(fps));
          frame_rate_ = std::min(kFakeCaptureMaxFrameRate, frame_rate_);
        }
      } else if (base::EqualsCaseInsensitiveASCII(param.front(),
                                                  "device-count")) {
        unsigned int count = 0;
        if (base::StringToUint(param.back(), &count)) {
          number_of_devices_ = std::min(
              kFakeCaptureMaxDeviceCount,
              std::max(kFakeCaptureMinDeviceCount, static_cast<int>(count)));
        }
      }
    }
  }
  
  }  // namespace media
  