The Tor Browser / file revision

 // 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_MESSAGE_ROUTER_H__

 #define CHROME_COMMON_MESSAGE_ROUTER_H__

 #include "base/id_map.h"

 #include "chrome/common/ipc_channel.h"

 // The MessageRouter handles all incoming messages sent to it by routing them

 // to the correct listener.  Routing is based on the Message's routing ID.

 // Since routing IDs are typically assigned asynchronously by the browser

 // process, the MessageRouter has the notion of pending IDs for listeners that

 // have not yet been assigned a routing ID.

 //

 // When a message arrives, the routing ID is used to index the set of routes to

 // find a listener.  If a listener is found, then the message is passed to it.

 // Otherwise, the message is ignored if its routing ID is not equal to

 // MSG_ROUTING_CONTROL.

 //

 // The MessageRouter supports the IPC::Message::Sender interface for outgoing

 // messages, but does not define a meaningful implementation of it.  The

 // subclass of MessageRouter is intended to provide that if appropriate.

 //

 // The MessageRouter can be used as a concrete class provided its Send method

 // is not called and it does not receive any control messages.

 class MessageRouter : public IPC::Channel::Listener,

                       public IPC::Message::Sender {

  public:

   MessageRouter() {}

   virtual ~MessageRouter() {}

   // Implemented by subclasses to handle control messages

   virtual void OnControlMessageReceived(const IPC::Message& msg);

   // IPC::Channel::Listener implementation:

   virtual void OnMessageReceived(const IPC::Message& msg);

   // Like OnMessageReceived, except it only handles routed messages.  Returns

   // true if the message was dispatched, or false if there was no listener for

   // that route id.

   virtual bool RouteMessage(const IPC::Message& msg);

   // IPC::Message::Sender implementation:

   virtual bool Send(IPC::Message* msg);

   // Called to add/remove a listener for a particular message routing ID.

   void AddRoute(int32_t routing_id, IPC::Channel::Listener* listener);

   void RemoveRoute(int32_t routing_id);

  private:

   // A list of all listeners with assigned routing IDs.

   IDMap<IPC::Channel::Listener> routes_;

   DISALLOW_EVIL_CONSTRUCTORS(MessageRouter);

 };

 #endif  // CHROME_COMMON_MESSAGE_ROUTER_H__