Factor out the shared parts of IPC channel reading.

ipc/ipc_channel.h

 // Copyright (c) 2011 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 IPC_IPC_CHANNEL_H_
 #define IPC_IPC_CHANNEL_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "ipc/ipc_channel_handle.h"
@@ skipping 76 matching lines @@
     MODE_NAMED_CLIENT = MODE_CLIENT_FLAG | MODE_NAMED_FLAG,
 #if defined(OS_POSIX)
     // An "open" named server accepts connections from ANY client.
     // The caller must then implement their own access-control based on the
     // client process' user Id.
     MODE_OPEN_NAMED_SERVER = MODE_OPEN_ACCESS_FLAG | MODE_SERVER_FLAG |
                              MODE_NAMED_FLAG
 #endif
   };
 
+  // The Hello message is internal to the Channel class.  It is sent
+  // by the peer when the channel is connected.  The message contains
+  // just the process id (pid).  The message has a special routing_id
+  // (MSG_ROUTING_NONE) and type (HELLO_MESSAGE_TYPE).
+  enum {
+    HELLO_MESSAGE_TYPE = kuint16max  // Maximum value of message type (uint16),
+                                     // to avoid conflicting with normal
+                                     // message types, which are enumeration
+                                     // constants starting from 0.
+  };
+
   // The maximum message size in bytes. Attempting to receive a message of this
   // size or bigger results in a channel error.
   static const size_t kMaximumMessageSize = 128 * 1024 * 1024;
 
   // Ammount of data to read at once from the pipe.
   static const size_t kReadBufferSize = 4 * 1024;
 
   // Initialize a Channel.
   //
   // |channel_handle| identifies the communication Channel. For POSIX, if
@@ skipping 83 matching lines @@
   // Used in Chrome by the TestSink to provide a dummy channel implementation
   // for testing. TestSink overrides the "interesting" functions in Channel so
   // no actual implementation is needed. This will cause un-overridden calls to
   // segfault. Do not use outside of test code!
   Channel() : channel_impl_(0) { }
 
  private:
   // PIMPL to which all channel calls are delegated.
   class ChannelImpl;
   ChannelImpl *channel_impl_;
-
-  // The Hello message is internal to the Channel class.  It is sent
-  // by the peer when the channel is connected.  The message contains
-  // just the process id (pid).  The message has a special routing_id
-  // (MSG_ROUTING_NONE) and type (HELLO_MESSAGE_TYPE).
-  enum {
-    HELLO_MESSAGE_TYPE = kuint16max  // Maximum value of message type (uint16),
-                                     // to avoid conflicting with normal
-                                     // message types, which are enumeration
-                                     // constants starting from 0.
-  };
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_H_