Add a ChannelEndpointClient abstraction.

mojo/edk/system/message_pipe.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_EDK_SYSTEM_MESSAGE_PIPE_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "mojo/edk/embedder/platform_handle_vector.h"
+#include "mojo/edk/system/channel_endpoint_client.h"
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/edk/system/handle_signals_state.h"
 #include "mojo/edk/system/memory.h"
 #include "mojo/edk/system/message_in_transit.h"
 #include "mojo/edk/system/message_pipe_endpoint.h"
 #include "mojo/edk/system/system_impl_export.h"
 #include "mojo/public/c/system/message_pipe.h"
 #include "mojo/public/c/system/types.h"
 
 namespace mojo {
 namespace system {
 
 class Channel;
 class ChannelEndpoint;
 class Waiter;
 
 // |MessagePipe| is the secondary object implementing a message pipe (see the
 // explanatory comment in core.cc). It is typically owned by the dispatcher(s)
 // corresponding to the local endpoints. This class is thread-safe.
-class MOJO_SYSTEM_IMPL_EXPORT MessagePipe
-    : public base::RefCountedThreadSafe<MessagePipe> {
+class MOJO_SYSTEM_IMPL_EXPORT MessagePipe : public ChannelEndpointClient {
  public:
   // Creates a |MessagePipe| with two new |LocalMessagePipeEndpoint|s.
   static MessagePipe* CreateLocalLocal();
 
   // Creates a |MessagePipe| with a |LocalMessagePipeEndpoint| on port 0 and a
   // |ProxyMessagePipeEndpoint| on port 1. |*channel_endpoint| is set to the
   // (newly-created) |ChannelEndpoint| for the latter.
   static MessagePipe* CreateLocalProxy(
       scoped_refptr<ChannelEndpoint>* channel_endpoint);
 
@@ skipping 54 matching lines @@
   bool EndSerialize(unsigned port,
                     Channel* channel,
                     void* destination,
                     size_t* actual_size,
                     embedder::PlatformHandleVector* platform_handles);
 
   // Used by |EndSerialize()|. TODO(vtl): Remove this (merge it into
   // |EndSerialize()|).
   scoped_refptr<ChannelEndpoint> ConvertLocalToProxy(unsigned port);
 
-  // This is used by |Channel| to enqueue messages (typically to a
-  // |LocalMessagePipeEndpoint|). Unlike |WriteMessage()|, |port| is the
-  // *destination* port.
-  MojoResult EnqueueMessage(unsigned port,
-                            scoped_ptr<MessageInTransit> message);
+  // |ChannelEndpointClient| methods:
+  virtual bool OnReadMessage(unsigned port,

[yzshen1, 2014/11/18 00:28:17]

nit: I think the current style guide prefers using "override" without "virtual",
and the same for the destructor.

[viettrungluu, 2014/11/18 00:47:30]

Done.

+                             scoped_ptr<MessageInTransit> message) override;
+  virtual void OnDetachFromChannel(unsigned port) override;
 
  private:
   MessagePipe();
+  virtual ~MessagePipe();
 
-  friend class base::RefCountedThreadSafe<MessagePipe>;
-  ~MessagePipe();
-
-  // This is used internally by |WriteMessage()| and by |EnqueueMessage()|.
+  // This is used internally by |WriteMessage()| and by |OnReadMessage()|.
   // |transports| may be non-null only if it's nonempty and |message| has no
   // dispatchers attached.
-  MojoResult EnqueueMessageInternal(
-      unsigned port,
-      scoped_ptr<MessageInTransit> message,
-      std::vector<DispatcherTransport>* transports);
+  MojoResult EnqueueMessage(unsigned port,
+                            scoped_ptr<MessageInTransit> message,
+                            std::vector<DispatcherTransport>* transports);
 
-  // Helper for |EnqueueMessageInternal()|. Must be called with |lock_| held.
+  // Helper for |EnqueueMessage()|. Must be called with |lock_| held.
   MojoResult AttachTransportsNoLock(
       unsigned port,
       MessageInTransit* message,
       std::vector<DispatcherTransport>* transports);
 
-  // Used by |EnqueueMessageInternal()| to handle control messages that are
-  // actually meant for us.
+  // Used by |EnqueueMessage()| to handle control messages that are actually
+  // meant for us.
   MojoResult HandleControlMessage(unsigned port,
                                   scoped_ptr<MessageInTransit> message);
 
   base::Lock lock_;  // Protects the following members.
   scoped_ptr<MessagePipeEndpoint> endpoints_[2];
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipe);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_H_