Split FakeVideoCaptureDevice into classes with single responsibility

media/capture/video/fake_video_capture_device_factory.cc

 // 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) {
+media::VideoPixelFormat GetPixelFormatFromDeviceId(
+    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),
+      delivery_mode_(
+          FakeVideoCaptureDeviceMaker::DeliveryMode::USE_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;
-  }
+  ParseCommandLine();
 
   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 FakeVideoCaptureDeviceMaker::MakeInstance(
+          GetPixelFormatFromDeviceId(possible_id), delivery_mode_, frame_rate_);
     }
   }
   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;
-  }
+  ParseCommandLine();
 
   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)));
+
+  ParseCommandLine();
+
+  const VideoPixelFormat pixel_format =
+      GetPixelFormatFromDeviceId(device_descriptor.device_id);
+  const VideoPixelStorage pixel_storage = PIXEL_STORAGE_CPU;
+  std::vector<gfx::Size> supported_sizes;
+  FakeVideoCaptureDeviceMaker::GetSupportedSizes(&supported_sizes);
+  for (const auto& supported_size : supported_sizes) {
+    supported_formats->emplace_back(supported_size, frame_rate_, pixel_format,
+                                    pixel_storage);
   }
 }
 
 // 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() {
+  if (command_line_parsed_)
+    return;
+  command_line_parsed_ = true;
+
   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;
+      delivery_mode_ =
+          FakeVideoCaptureDeviceMaker::DeliveryMode::USE_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