Add the ability for objects which derive from RefCountedThreadSafe to specify...

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 28 matching lines @@
 // the consumer of IPC::ChannelProxy the ability to respond to incoming
 // 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);
+  };
+
   // 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> {
+  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
     // is called if the channel is already initialized.
     virtual void OnFilterAdded(Channel* channel) {}
 
     // Called on the background thread when the filter has been removed from
     // the ChannelProxy and when the Channel is closing.  After a filter is
@@ skipping 10 matching lines @@
 
     // Called to inform the filter that the IPC channel will be destroyed.
     // OnFilterRemoved is called immediately after this.
     virtual void OnChannelClosing() {}
 
     // Return true to indicate that the message was handled, or false to let
     // the message be handled in the default way.
     virtual bool OnMessageReceived(const Message& message) {
       return false;
     }
+
+    // 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;
+    }
   };
 
   // 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.
@@ skipping 117 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__