[mojo-edk] Expose portable API for platform handle wrapping

mojo/public/cpp/system/platform_handle.h

+// 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.
+
+// This file provides a C++ wrapping around the Mojo C API for platform handles,
+// replacing the prefix of "Mojo" with a "mojo" namespace.
+//
+// Please see "mojo/public/c/system/platform_handle.h" for complete
+// documentation of the API.
+
+#ifndef MOJO_PUBLIC_CPP_SYSTEM_PLATFORM_HANDLE_H_
+#define MOJO_PUBLIC_CPP_SYSTEM_PLATFORM_HANDLE_H_
+
+#include <stdint.h>
+
+#include "base/compiler_specific.h"
+#include "base/files/file.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/memory/shared_memory_handle.h"
+#include "base/process/process_handle.h"
+#include "mojo/public/c/system/platform_handle.h"
+#include "mojo/public/cpp/system/buffer.h"
+#include "mojo/public/cpp/system/handle.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+
+namespace mojo {
+
+#if defined(OS_POSIX)
+
+const MojoPlatformHandleType kPlatformFileHandleType =
+    MOJO_PLATFORM_HANDLE_TYPE_FILE_DESCRIPTOR;
+const base::PlatformFile kInvalidPlatformFile = -1;
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+const MojoPlatformHandleType kPlatformSharedBufferHandleType =
+    MOJO_PLATFORM_HANDLE_TYPE_MACH_PORT;
+#else
+const MojoPlatformHandleType kPlatformSharedBufferHandleType =
+    MOJO_PLATFORM_HANDLE_TYPE_FILE_DESCRIPTOR;
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
+
+#elif defined(OS_WIN)
+const MojoPlatformHandleType kPlatformFileHandleType =
+    MOJO_PLATFORM_HANDLE_TYPE_WINDOWS_HANDLE;
+const base::PlatformFile kInvalidPlatformFile = INVALID_HANDLE_VALUE;
+
+const MojoPlatformHandleType kPlatformSharedBufferHandleType =
+    MOJO_PLATFORM_HANDLE_TYPE_WINDOWS_HANDLE;
+#endif  // defined(OS_POSIX)
+
+// Wraps a PlatformFile as a Mojo handle. Takes ownership of the file object.
+ScopedHandle WrapPlatformFile(base::PlatformFile platform_file);
+
+// Unwraps a PlatformFile from a Mojo handle.
+MojoResult UnwrapPlatformFile(ScopedHandle handle, base::PlatformFile* file);
+
+// Wraps a base::SharedMemoryHandle as a Mojo handle. Takes ownership of the
+// SharedMemoryHandle. Note that |read_only| is only an indicator of whether
+// |memory_handle| only supports read-only mapping. It does NOT have any
+// influence on the access control of the shared buffer object.
+ScopedSharedBufferHandle WrapSharedMemoryHandle(
+    const base::SharedMemoryHandle& memory_handle,
+    size_t size,
+    bool read_only);
+
+// Unwraps a base::SharedMemoryHandle from a Mojo handle. The caller assumes
+// responsibility for the lifetime of the SharedMemoryHandle.
+MojoResult UnwrapSharedMemoryHandle(ScopedSharedBufferHandle handle,
+                                    base::SharedMemoryHandle* memory_handle,
+                                    size_t* size,
+                                    bool* read_only);
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_SYSTEM_PLATFORM_HANDLE_H_