Video Capture Service: typemap video_capture's and media's VideoCaptureFormat

services/video_capture/public/interfaces/video_capture_format_traits.cc

+// Copyright 2016 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 "services/video_capture/public/interfaces/video_capture_format_traits.h"
+
+#include "ui/gfx/geometry/mojo/geometry.mojom.h"
+#include "ui/gfx/geometry/mojo/geometry_struct_traits.h"
+
+namespace mojo {
+
+// static
+gfx::Size StructTraits<video_capture::mojom::VideoCaptureFormatDataView,
+                       media::VideoCaptureFormat>::
+    frame_size(const media::VideoCaptureFormat& format) {
+  return gfx::Size(format.frame_size.width(), format.frame_size.height());

[dcheng, 2016/10/04 01:33:18]

Return a const gfx::Size& and return format.frame_size directly here.

[dcheng, 2016/10/04 01:34:37]

Btw, I should have elaborated in my original message: the reason it's important
to do this is because struct traits "getters" like this are actually called
twice on serialization: so generally, they should be cheap and do minimal work
and just return a "view" of the data.

[mcasas, 2016/10/04 02:46:20]

Done.

+}
+
+// static
+float StructTraits<video_capture::mojom::VideoCaptureFormatDataView,
+                   media::VideoCaptureFormat>::
+    frame_rate(const media::VideoCaptureFormat& format) {
+  return format.frame_rate;

[dcheng, 2016/10/04 01:33:18]

Re: inline vs not-inline

If it's just calling a simple getter, it's OK to inline.

If it's more complicated than that, we should not inline it. So these things are
all OK to inline (including the frame_size getter above, once it returns a const
ref to the size member directly) as well as the ones below that just cast enum
types.

[mcasas, 2016/10/04 02:46:20]

Done.

+}
+
+// static
+media::mojom::VideoFormat StructTraits<
+    video_capture::mojom::VideoCaptureFormatDataView,
+    media::VideoCaptureFormat>::pixel_format(const media::VideoCaptureFormat&
+                                                 format) {
+  return media::mojom::VideoFormat(format.pixel_format);

[dcheng, 2016/10/04 01:33:18]

Nit: use static_cast to convert between types

[mcasas, 2016/10/04 02:46:20]

Done.

+}
+
+// static
+video_capture::mojom::VideoPixelStorage StructTraits<
+    video_capture::mojom::VideoCaptureFormatDataView,
+    media::VideoCaptureFormat>::pixel_storage(const media::VideoCaptureFormat&
+                                                  format) {
+  return video_capture::mojom::VideoPixelStorage(format.pixel_storage);
+}
+
+// static
+bool StructTraits<video_capture::mojom::VideoCaptureFormatDataView,
+                  media::VideoCaptureFormat>::
+    Read(video_capture::mojom::VideoCaptureFormatDataView data,
+         media::VideoCaptureFormat* out) {
+  if (!data.ReadFrameSize(&out->frame_size))
+    return false;
+  out->frame_rate = data.frame_rate();
+
+  // Since there are static_asserts in place in
+  // media/mojo/common/media_type_converters.cc to guarantee equality of the
+  // underlying representations, we can simply static_cast to convert.
+  // TODO(mcasas): Use EnumTraits for VideoPixelFormat, https://crbug.com/651897
+  out->pixel_format =
+      static_cast<media::VideoPixelFormat>(data.pixel_format());
+  if (!data.ReadPixelStorage(&out->pixel_storage))
+    return false;
+  return true;
+}
+
+// static
+video_capture::mojom::VideoPixelStorage
+EnumTraits<video_capture::mojom::VideoPixelStorage, media::VideoPixelStorage>::
+    ToMojom(media::VideoPixelStorage video_pixel_storage) {
+  switch (video_pixel_storage) {
+    case media::PIXEL_STORAGE_CPU:
+      return video_capture::mojom::VideoPixelStorage::CPU;
+    case media::PIXEL_STORAGE_GPUMEMORYBUFFER:
+      return video_capture::mojom::VideoPixelStorage::GPUMEMORYBUFFER;
+  }
+  NOTREACHED();
+  return video_capture::mojom::VideoPixelStorage::CPU;
+}
+
+// static
+bool EnumTraits<video_capture::mojom::VideoPixelStorage,
+                media::VideoPixelStorage>::
+    FromMojom(video_capture::mojom::VideoPixelStorage input,
+              media::VideoPixelStorage* out) {
+  switch (input) {
+    case video_capture::mojom::VideoPixelStorage::CPU:
+      *out = media::PIXEL_STORAGE_CPU;
+      return true;
+    case video_capture::mojom::VideoPixelStorage::GPUMEMORYBUFFER:
+      *out = media::PIXEL_STORAGE_GPUMEMORYBUFFER;
+      return true;
+  }
+  NOTREACHED();
+  return false;
+}
+
+}  // namespace mojo