Mojo: Abstract out write/writev vs send/sendmsg (for Unix domain sockets).

mojo/embedder/platform_channel_utils_posix.h

+// 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.
+
+#ifndef MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
+#define MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
+
+#include <stddef.h>
+#include <sys/types.h>  // For |ssize_t|.
+
+#include "mojo/embedder/platform_handle.h"
+#include "mojo/system/system_impl_export.h"
+
+struct iovec;  // Declared in <sys/uio.h>.
+
+namespace mojo {
+namespace embedder {
+
+// Use these to write to a socket created using |PlatformChannelPair| (or
+// equivalent). These are like |write()| and |writev()|, but handle |EINTR| and
+// never raise |SIGPIPE|. (Note: On Mac, the suppression of |SIGPIPE| is set up
+// by |PlatformChannelPair|.)
+MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelWrite(PlatformHandle h,
+                                                     const void* bytes,
+                                                     size_t num_bytes);
+MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelWritev(PlatformHandle h,
+                                                      struct iovec* iov,
+                                                      size_t num_iov);
+
+}  // namespace embedder
+}  // namespace mojo
+
+#endif  // MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_