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

mojo/embedder/platform_channel_pair.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_PAIR_H_
 #define MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/process/launch.h"
@@ skipping 27 matching lines @@
 //
 // This class provides facilities for passing the client handle to a child
 // process. The parent should call |PrepareToPassClientHandlelToChildProcess()|
 // to get the data needed to do this, spawn the child using that data, and then
 // call |ChildProcessLaunched()|. Note that on Windows this facility (will) only
 // work on Vista and later (TODO(vtl)).
 //
 // Note: |PlatformChannelPair()|, |PassClientHandleFromParentProcess()| and
 // |PrepareToPassClientHandleToChildProcess()| have platform-specific
 // implementations.
+//
+// Note: On POSIX platforms, to write to the "pipe", use
+// |PlatformChannel{Write,Writev}()| (from platform_channel_utils_posix.h)
+// instead of |write()|, |writev()|, etc. Otherwise, you have to worry about
+// platform differences in suppressing |SIGPIPE|.
 class MOJO_SYSTEM_IMPL_EXPORT PlatformChannelPair {
  public:
   PlatformChannelPair();
   ~PlatformChannelPair();
 
   ScopedPlatformHandle PassServerHandle();
 
   // For in-process use (e.g., in tests or to pass over another channel).
   ScopedPlatformHandle PassClientHandle();
 
@@ skipping 22 matching lines @@
   ScopedPlatformHandle server_handle_;
   ScopedPlatformHandle client_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformChannelPair);
 };
 
 }  // namespace embedder
 }  // namespace mojo
 
 #endif  // MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_