First patch in making destructors of refcounted objects private.

ipc/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 IPC_IPC_CHANNEL_PROXY_H__
 #define IPC_IPC_CHANNEL_PROXY_H__
 
 #include <vector>
 
 #include "base/ref_counted.h"
@@ skipping 29 matching lines @@
 // messages on this background thread instead of on their own thread, which may
 // be bogged down with other processing.  The result can be greatly improved
 // latency for messages that can be handled on a background thread.
 //
 // The consumer of IPC::ChannelProxy is responsible for allocating the Thread
 // instance where the IPC::Channel will be created and operated.
 //
 class ChannelProxy : public Message::Sender {
  public:
 
-  class MessageFilter;
-  struct MessageFilterTraits {
-    static void Destruct(MessageFilter* filter);
-  };
+  struct MessageFilterTraits;
 
   // A class that receives messages on the thread where the IPC channel is
   // running.  It can choose to prevent the default action for an IPC message.
   class MessageFilter
       : public base::RefCountedThreadSafe<MessageFilter, MessageFilterTraits> {
    public:
     virtual ~MessageFilter() {}
 
     // Called on the background thread to provide the filter with access to the
     // channel.  Called when the IPC channel is initialized or when AddFilter
@@ skipping 24 matching lines @@
     }
 
     // Called when the message filter is about to be deleted.  This gives
     // derived classes the option of controlling which thread they're deleted
     // on etc.
     virtual void OnDestruct() {
       delete this;
     }
   };
 
+  struct MessageFilterTraits {
+    static void Destruct(MessageFilter* filter) {
+      filter->OnDestruct();
+    }
+  };
+
   // Initializes a channel proxy.  The channel_id and mode parameters are
   // passed directly to the underlying IPC::Channel.  The listener is called on
   // the thread that creates the ChannelProxy.  The filter's OnMessageReceived
   // method is called on the thread where the IPC::Channel is running.  The
   // filter may be null if the consumer is not interested in handling messages
   // on the background thread.  Any message not handled by the filter will be
   // dispatched to the listener.  The given message loop indicates where the
   // IPC::Channel should be created.
   ChannelProxy(const std::string& channel_id, Channel::Mode mode,
                Channel::Listener* listener, MessageFilter* filter,
@@ skipping 43 matching lines @@
   ChannelProxy(const std::string& 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() { }
     void ClearIPCMessageLoop() { ipc_message_loop_ = NULL; }
     MessageLoop* ipc_message_loop() const { return ipc_message_loop_; }
     const std::string& channel_id() const { return channel_id_; }
 
     // Dispatches a message on the listener thread.
     void OnDispatchMessage(const Message& message);
 
    protected:
+    friend class base::RefCountedThreadSafe<Context>;

[M-A Ruel, 2009/11/05 20:31:28]

protected?

[jam, 2009/11/05 21:52:37]

yeah, because SyncContext derives from it.

+    virtual ~Context() { }
+
     // 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);
 
     // 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;
     friend class SendTask;
+
     // Create the Channel
     void CreateChannel(const std::string& id, const Channel::Mode& mode);
 
     // Methods called via InvokeLater:
     void OnSendMessage(Message* message_ptr);
     void OnAddFilter(MessageFilter* filter);
     void OnRemoveFilter(MessageFilter* filter);
     void OnDispatchConnected();
     void OnDispatchError();
 
@@ skipping 19 matching lines @@
 
   // 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  // IPC_IPC_CHANNEL_PROXY_H__