mus: Add support for sending IOSurface mach_ports over mojo.

BUG=643746

Review-Url: https://codereview.chromium.org/2537423004
Cr-Commit-Position: refs/heads/master@{#436161}

mojo/public/cpp/system/platform_handle.cc

@@ -4,6 +4,11 @@
 
 #include "mojo/public/cpp/system/platform_handle.h"
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+#include <mach/mach.h>
+#include "base/mac/mach_logging.h"
+#endif
+
 namespace mojo {
 
 namespace {
@@ -126,4 +131,39 @@ MojoResult UnwrapSharedMemoryHandle(ScopedSharedBufferHandle handle,
   return MOJO_RESULT_OK;
 }
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+ScopedHandle WrapMachPort(mach_port_t port) {
+  kern_return_t kr =
+      mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_SEND, 1);
+  MACH_LOG_IF(ERROR, kr != KERN_SUCCESS, kr)
+      << "MachPortAttachmentMac mach_port_mod_refs";
+  if (kr != KERN_SUCCESS)
+    return ScopedHandle();
+
+  MojoPlatformHandle platform_handle;
+  platform_handle.struct_size = sizeof(MojoPlatformHandle);
+  platform_handle.type = MOJO_PLATFORM_HANDLE_TYPE_MACH_PORT;
+  platform_handle.value = static_cast<uint64_t>(port);
+
+  MojoHandle mojo_handle;
+  MojoResult result = MojoWrapPlatformHandle(&platform_handle, &mojo_handle);
+  CHECK_EQ(result, MOJO_RESULT_OK);
+
+  return ScopedHandle(Handle(mojo_handle));
+}
+
+MojoResult UnwrapMachPort(ScopedHandle handle, mach_port_t* port) {
+  MojoPlatformHandle platform_handle;
+  platform_handle.struct_size = sizeof(MojoPlatformHandle);
+  MojoResult result =
+      MojoUnwrapPlatformHandle(handle.release().value(), &platform_handle);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  CHECK_EQ(platform_handle.type, MOJO_PLATFORM_HANDLE_TYPE_MACH_PORT);
+  *port = static_cast<mach_port_t>(platform_handle.value);
+  return MOJO_RESULT_OK;
+}
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
+
 }  // namespace mojo

mojo/public/cpp/system/platform_handle.h

@@ -76,6 +76,17 @@ UnwrapSharedMemoryHandle(ScopedSharedBufferHandle handle,
                          size_t* size,
                          bool* read_only);
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+// Wraps a mach_port_t as a Mojo handle. This takes a reference to the
+// Mach port.
+MOJO_CPP_SYSTEM_EXPORT ScopedHandle WrapMachPort(mach_port_t port);
+
+// Unwraps a mach_port_t from a Mojo handle. The caller gets ownership of the
+// Mach port.
+MOJO_CPP_SYSTEM_EXPORT MojoResult UnwrapMachPort(ScopedHandle handle,
+                                                 mach_port_t* port);
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
+
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_SYSTEM_PLATFORM_HANDLE_H_

ui/gfx/mojo/buffer_types.mojom

@@ -74,5 +74,5 @@ struct GpuMemoryBufferHandle {
   uint32 offset;
   uint32 stride;
   NativePixmapHandle? native_pixmap_handle;
-  // TODO: Add support for mach_port on mac.
+  handle? mach_port;
 };

ui/gfx/mojo/buffer_types_traits.cc

@@ -88,6 +88,18 @@ StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
 #endif
 }
 
+mojo::ScopedHandle StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
+                                gfx::GpuMemoryBufferHandle>::
+    mach_port(const gfx::GpuMemoryBufferHandle& handle) {
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  if (handle.type != gfx::IO_SURFACE_BUFFER)
+    return mojo::ScopedHandle();
+  return mojo::WrapMachPort(handle.mach_port.get());
+#else
+  return mojo::ScopedHandle();
+#endif
+}
+
 bool StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
                   gfx::GpuMemoryBufferHandle>::
     Read(gfx::mojom::GpuMemoryBufferHandleDataView data,
@@ -121,6 +133,16 @@ bool StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
   if (out->type == gfx::OZONE_NATIVE_PIXMAP &&
       !data.ReadNativePixmapHandle(&out->native_pixmap_handle))
     return false;
+#endif
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  if (out->type == gfx::IO_SURFACE_BUFFER) {
+    mach_port_t mach_port;
+    MojoResult unwrap_result =
+        mojo::UnwrapMachPort(data.TakeMachPort(), &mach_port);
+    if (unwrap_result != MOJO_RESULT_OK)
+      return false;
+    out->mach_port.reset(mach_port);
+  }
 #endif
   return true;
 }

ui/gfx/mojo/buffer_types_traits.h

@@ -269,6 +269,7 @@ struct StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
   }
   static const gfx::NativePixmapHandle& native_pixmap_handle(
       const gfx::GpuMemoryBufferHandle& handle);
+  static mojo::ScopedHandle mach_port(const gfx::GpuMemoryBufferHandle& handle);
   static bool Read(gfx::mojom::GpuMemoryBufferHandleDataView data,
                    gfx::GpuMemoryBufferHandle* handle);
 };