Make IPC::SyncChannel not duplicate the underlying MessageLoop implementation...

chrome/common/ipc_channel_proxy.h

 // Copyright (c) 2006-2008 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 CHROME_COMMON_IPC_CHANNEL_PROXY_H__
 #define CHROME_COMMON_IPC_CHANNEL_PROXY_H__
 
 #include <vector>
 #include "base/lock.h"
 #include "base/ref_counted.h"
@@ skipping 94 matching lines @@
 
   // Used to intercept messages as they are received on the background thread.
   //
   // Ordinarily, messages sent to the ChannelProxy are routed to the matching
   // listener on the worker thread.  This API allows code to intercept messages
   // before they are sent to the worker thread.
   void AddFilter(MessageFilter* filter);
   void RemoveFilter(MessageFilter* filter);
 
  protected:
-  Channel::Listener* listener() const { return context_->listener(); }
-
   class Context;
   // A subclass uses this constructor if it needs to add more information
   // to the internal state.  If create_pipe_now is true, the pipe is created
   // immediately.  Otherwise it's created on the IO thread.
   ChannelProxy(const std::wstring& channel_id, Channel::Mode mode,
                MessageLoop* ipc_thread_loop, Context* context,
                bool create_pipe_now);
 
   // Used internally to hold state that is referenced on the IPC thread.
   class Context : public base::RefCountedThreadSafe<Context>,
                   public Channel::Listener {
    public:
     Context(Channel::Listener* listener, MessageFilter* filter,
             MessageLoop* ipc_thread);
     virtual ~Context() { }
+    MessageLoop* ipc_message_loop() const { return ipc_message_loop_; }
 
   protected:
     // IPC::Channel::Listener methods:
     virtual void OnMessageReceived(const Message& message);
     virtual void OnChannelConnected(int32 peer_pid);
     virtual void OnChannelError();
 
+    // Like OnMessageReceived but doesn't try the filters.
+    void OnMessageReceivedNoFilter(const Message& message);
+
     Channel::Listener* listener() const { return listener_; }
     const std::wstring& channel_id() const { return channel_id_; }
 
     // Gives the filters a chance at processing |message|.
     // Returns true if the message was processed, false otherwise.
     bool TryFilters(const Message& message);
 
+    // Like Open and Close, but called on the IPC thread.
+    virtual void OnChannelOpened();
+    virtual void OnChannelClosed();
+
+    // Called on the consumers thread when the ChannelProxy is closed.  At that
+    // point the consumer is telling us that they don't want to receive any
+    // more messages, so we honor that wish by forgetting them!
+    virtual void Clear() { listener_ = NULL; }
+
    private:
     friend class ChannelProxy;
     // Create the Channel
     void CreateChannel(const std::wstring& id, const Channel::Mode& mode);
 
     // Methods called via InvokeLater:
-    void OnOpenChannel();
-    void OnCloseChannel();
     void OnSendMessage(Message* message_ptr);
     void OnAddFilter(MessageFilter* filter);
     void OnRemoveFilter(MessageFilter* filter);
     void OnDispatchMessage(const Message& message);
     void OnDispatchConnected(int32 peer_pid);
     void OnDispatchError();
 
-    MessageLoop* ipc_message_loop() const { return ipc_message_loop_; }
-
-    // Called on the consumers thread when the ChannelProxy is closed.  At that
-    // point the consumer is telling us that they don't want to receive any
-    // more messages, so we honor that wish by forgetting them!
-    void clear() { listener_ = NULL; }
-
     MessageLoop* listener_message_loop_;
     Channel::Listener* listener_;
 
     // List of filters.  This is only accessed on the IPC thread.
     std::vector<scoped_refptr<MessageFilter>> filters_;
     MessageLoop* ipc_message_loop_;
     Channel* channel_;
     std::wstring channel_id_;
   };
 
   Context* context() { return context_; }
 
  private:
   void Init(const std::wstring& channel_id, Channel::Mode mode,
             MessageLoop* ipc_thread_loop, bool create_pipe_now);
 
   // By maintaining this indirection (ref-counted) to our internal state, we
   // can safely be destroyed while the background thread continues to do stuff
   // that involves this data.
   scoped_refptr<Context> context_;
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_IPC_CHANNEL_PROXY_H__