media: Create Mojo StructTraits for VideoFrame

media/mojo/interfaces/video_frame_struct_traits.h

+// Copyright 2017 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.
+
+#ifndef MEDIA_MOJO_INTERFACES_VIDEO_FRAME_STRUCT_TRAITS_H_
+#define MEDIA_MOJO_INTERFACES_VIDEO_FRAME_STRUCT_TRAITS_H_
+
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "media/base/video_frame.h"
+#include "media/mojo/common/mojo_shared_buffer_video_frame.h"
+#include "media/mojo/interfaces/media_types.mojom.h"
+#include "mojo/public/cpp/bindings/struct_traits.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<media::mojom::VideoFrameDataView,
+                    scoped_refptr<media::VideoFrame>> {
+  static bool IsNull(const scoped_refptr<media::VideoFrame>& input) {
+    return !!input;
+  }
+
+  static void SetToNull(scoped_refptr<media::VideoFrame>* input) {
+    *input = nullptr;
+  }
+
+  static media::VideoPixelFormat format(
+      const scoped_refptr<media::VideoFrame>& input) {
+    return input->format();
+  }
+
+  static gfx::Size coded_size(const scoped_refptr<media::VideoFrame>& input) {

[dcheng, 2017/06/05 20:33:02]

Nit: return non-trivial types by const ref: due to https://crbug.com/681080, we
currently call each serialization getter twice.

[sandersd (OOO until July 31), 2017/06/06 01:05:47]

This is the first time I've heard gfx::Size referred to as "non-trivial", but
done.

+    return input->coded_size();
+  }
+
+  static gfx::Rect visible_rect(const scoped_refptr<media::VideoFrame>& input) {
+    return input->visible_rect();
+  }
+
+  static gfx::Size natural_size(const scoped_refptr<media::VideoFrame>& input) {
+    return input->natural_size();
+  }
+
+  static bool end_of_stream(const scoped_refptr<media::VideoFrame>& input) {
+    return input->metadata()->IsTrue(media::VideoFrameMetadata::END_OF_STREAM);

[dcheng, 2017/06/05 20:33:01]

I'm assuming this is a cheap calculation (otherwise, we run into the
aforementioned serialization issue)

[sandersd (OOO until July 31), 2017/06/05 20:46:13]

This one should be fine.

+  }
+
+  static base::TimeDelta timestamp(

[dcheng, 2017/06/05 20:33:01]

But returning base::Time* by value is fine.

[sandersd (OOO until July 31), 2017/06/06 01:05:47]

Acknowledged.

+      const scoped_refptr<media::VideoFrame>& input) {
+    return input->timestamp();
+  }
+
+  static media::mojom::VideoFrameDataPtr data(
+      const scoped_refptr<media::VideoFrame>& input) {

[dcheng, 2017/06/05 20:33:02]

Hmm, isn't this in the .cc as well? I'm assuming this is duplicated by accident
and reviewing what's in .cc.

[sandersd (OOO until July 31), 2017/06/05 20:46:13]

Yes, it is, but they should have identical content. The version in this .h is
the one currently being used, I have not been able to get it to compile with the
.cc version yet. I'll follow up later today with my situation there to get
specific advice.

+    // EOS frames contain no data.
+    if (input->metadata()->IsTrue(media::VideoFrameMetadata::END_OF_STREAM))
+      return nullptr;
+
+    if (input->storage_type() ==
+        media::VideoFrame::STORAGE_MOJO_SHARED_BUFFER) {
+      media::MojoSharedBufferVideoFrame* mojo_frame =
+          static_cast<media::MojoSharedBufferVideoFrame*>(input.get());
+
+      // TODO(jrummell): Should this really be a writable clone?
+      mojo::ScopedSharedBufferHandle duplicated_handle =
+          mojo_frame->Handle().Clone();
+      DCHECK(duplicated_handle.is_valid());
+
+      return media::mojom::VideoFrameData::NewSharedBufferData(
+          media::mojom::SharedBufferVideoFrameData::New(
+              std::move(duplicated_handle), mojo_frame->MappedSize(),
+              mojo_frame->stride(media::VideoFrame::kYPlane),
+              mojo_frame->stride(media::VideoFrame::kUPlane),
+              mojo_frame->stride(media::VideoFrame::kVPlane),
+              mojo_frame->PlaneOffset(media::VideoFrame::kYPlane),
+              mojo_frame->PlaneOffset(media::VideoFrame::kUPlane),
+              mojo_frame->PlaneOffset(media::VideoFrame::kVPlane)));
+    }
+
+    if (input->HasTextures()) {
+      // TODO(sandersd): Friend VideoFrame so that we can access the array?
+      std::vector<gpu::MailboxHolder> mailbox_holder(
+          media::VideoFrame::kMaxPlanes);
+      for (size_t i = 0; i < media::VideoFrame::kMaxPlanes; i++)
+        mailbox_holder.push_back(input->mailbox_holder(i));
+      return media::mojom::VideoFrameData::NewMailboxData(
+          media::mojom::MailboxVideoFrameData::New(std::move(mailbox_holder)));
+    }
+
+    NOTREACHED() << "Unsupported VideoFrame conversion";
+    return nullptr;
+  }
+
+  static bool Read(media::mojom::VideoFrameDataView input,

[dcheng, 2017/06/05 20:33:02]

Ditto.

[sandersd (OOO until July 31), 2017/06/06 01:05:47]

Acknowledged.

+                   scoped_refptr<media::VideoFrame>* output) {
+    // View of the |data| member of the input media::mojom::VideoFrame.
+    media::mojom::VideoFrameDataDataView data;
+    input.GetDataDataView(&data);
+
+    DCHECK_EQ(input.end_of_stream(), data.is_null());
+    if (input.end_of_stream()) {
+      *output = media::VideoFrame::CreateEOSFrame();
+      return true;
+    }
+
+    media::VideoPixelFormat format;
+    if (!input.ReadFormat(&format))
+      return false;
+
+    gfx::Size coded_size;
+    if (!input.ReadCodedSize(&coded_size))
+      return false;
+
+    gfx::Rect visible_rect;
+    if (!input.ReadVisibleRect(&visible_rect))
+      return false;
+
+    gfx::Size natural_size;
+    if (!input.ReadNaturalSize(&natural_size))
+      return false;
+
+    base::TimeDelta timestamp;
+    if (!input.ReadTimestamp(&timestamp))
+      return false;
+
+    if (data.is_shared_buffer_data()) {
+      media::mojom::SharedBufferVideoFrameDataDataView shared_buffer_data;
+      data.GetSharedBufferDataDataView(&shared_buffer_data);
+
+      *output = media::MojoSharedBufferVideoFrame::Create(
+          format, coded_size, visible_rect, natural_size,
+          shared_buffer_data.TakeFrameData(),
+          shared_buffer_data.frame_data_size(), shared_buffer_data.y_offset(),
+          shared_buffer_data.u_offset(), shared_buffer_data.v_offset(),
+          shared_buffer_data.y_stride(), shared_buffer_data.u_stride(),
+          shared_buffer_data.v_stride(), timestamp);
+      return true;
+    }
+
+    if (data.is_mailbox_data()) {
+      media::mojom::MailboxVideoFrameDataDataView mailbox_data;
+      data.GetMailboxDataDataView(&mailbox_data);
+
+      std::vector<gpu::MailboxHolder> mailbox_holder;
+      if (!mailbox_data.ReadMailboxHolder(&mailbox_holder))
+        return false;
+
+      DCHECK_EQ(mailbox_holder.size(), media::VideoFrame::kMaxPlanes);
+      gpu::MailboxHolder mailbox_holder_array[media::VideoFrame::kMaxPlanes];
+      for (size_t i = 0; i < media::VideoFrame::kMaxPlanes; i++)
+        mailbox_holder_array[i] = mailbox_holder[i];
+
+      *output = media::VideoFrame::WrapNativeTextures(
+          format, mailbox_holder_array, media::VideoFrame::ReleaseMailboxCB(),
+          coded_size, visible_rect, natural_size, timestamp);
+      return true;
+    }
+
+    // TODO(sandersd): Switch on the union tag to avoid this ugliness?
+    NOTREACHED();
+    return false;
+  }
+};
+
+}  // namespace mojo
+
+#endif  // MEDIA_MOJO_INTERFACES_VIDEO_FRAME_STRUCT_TRAITS_H_