Mojo: First stab at making MessagePipes work across OS pipes.

mojo/system/message_pipe_endpoint.h

 // Copyright 2013 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_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_
 #define MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_
 
 #include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
 #include "mojo/public/system/core.h"
+#include "mojo/public/system/system_export.h"
+#include "mojo/system/message_in_transit.h"
 
 namespace mojo {
 namespace system {
 
+class Channel;
 class Waiter;
 
 // This is an interface to one of the ends of a message pipe, and is used by
 // |MessagePipe|. Its most important role is to provide a sink for messages
 // (i.e., a place where messages can be sent). It has a secondary role: When the
 // endpoint is local (i.e., in the current process), there'll be a dispatcher
 // corresponding to the endpoint. In that case, the implementation of
 // |MessagePipeEndpoint| also implements the functionality required by the
 // dispatcher, e.g., to read messages and to wait. Implementations of this class
 // are not thread-safe; instances are protected by |MesssagePipe|'s lock.
-class MessagePipeEndpoint {
+class MOJO_SYSTEM_EXPORT MessagePipeEndpoint {
  public:
   virtual ~MessagePipeEndpoint() {}
 
   // All implementations must implement these.
-  virtual void OnPeerClose() = 0;
-  virtual MojoResult EnqueueMessage(
-      const void* bytes, uint32_t num_bytes,
-      const MojoHandle* handles, uint32_t num_handles,
-      MojoWriteMessageFlags flags) = 0;
+  virtual void Close() = 0;
+  // Returns false if the endpoint should be closed and destroyed, else true.
+  virtual bool OnPeerClose() = 0;
+  // Takes ownership of |message|.
+  virtual MojoResult EnqueueMessage(MessageInTransit* message) = 0;
 
   // Implementations must override these if they represent a local endpoint,
   // i.e., one for which there's a |MessagePipeDispatcher| (and thus a handle).
-  // An implementation for a remote endpoint (for which there's no dispatcher)
+  // An implementation for a proxy endpoint (for which there's no dispatcher)
   // needs not override these methods, since they should never be called.
   //
   // These methods implement the methods of the same name in |MessagePipe|,
   // though |MessagePipe|'s implementation may have to do a little more if the
   // operation involves both endpoints.
   virtual void CancelAllWaiters();
-  virtual void Close();
   virtual MojoResult ReadMessage(void* bytes, uint32_t* num_bytes,
                                  MojoHandle* handles, uint32_t* num_handles,
                                  MojoReadMessageFlags flags);
   virtual MojoResult AddWaiter(Waiter* waiter,
                                MojoWaitFlags flags,
                                MojoResult wake_result);
   virtual void RemoveWaiter(Waiter* waiter);
 
+  // Implementations must override these if they represent a proxy endpoint. An
+  // implementation for a local endpoint needs not override these methods, since
+  // they should never be called.
+  virtual void Attach(scoped_refptr<Channel> channel,
+                      MessageInTransit::EndpointId local_id);
+  // Returns false if the endpoint should be closed and destroyed, else true.
+  virtual bool Run(MessageInTransit::EndpointId remote_id);
+
  protected:
   MessagePipeEndpoint() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MessagePipeEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_