michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef CHROME_COMMON_MESSAGE_ROUTER_H__
michael@0: #define CHROME_COMMON_MESSAGE_ROUTER_H__
michael@0: 
michael@0: #include "base/id_map.h"
michael@0: #include "chrome/common/ipc_channel.h"
michael@0: 
michael@0: // The MessageRouter handles all incoming messages sent to it by routing them
michael@0: // to the correct listener.  Routing is based on the Message's routing ID.
michael@0: // Since routing IDs are typically assigned asynchronously by the browser
michael@0: // process, the MessageRouter has the notion of pending IDs for listeners that
michael@0: // have not yet been assigned a routing ID.
michael@0: //
michael@0: // When a message arrives, the routing ID is used to index the set of routes to
michael@0: // find a listener.  If a listener is found, then the message is passed to it.
michael@0: // Otherwise, the message is ignored if its routing ID is not equal to
michael@0: // MSG_ROUTING_CONTROL.
michael@0: //
michael@0: // The MessageRouter supports the IPC::Message::Sender interface for outgoing
michael@0: // messages, but does not define a meaningful implementation of it.  The
michael@0: // subclass of MessageRouter is intended to provide that if appropriate.
michael@0: //
michael@0: // The MessageRouter can be used as a concrete class provided its Send method
michael@0: // is not called and it does not receive any control messages.
michael@0: 
michael@0: class MessageRouter : public IPC::Channel::Listener,
michael@0:                       public IPC::Message::Sender {
michael@0:  public:
michael@0:   MessageRouter() {}
michael@0:   virtual ~MessageRouter() {}
michael@0: 
michael@0:   // Implemented by subclasses to handle control messages
michael@0:   virtual void OnControlMessageReceived(const IPC::Message& msg);
michael@0: 
michael@0:   // IPC::Channel::Listener implementation:
michael@0:   virtual void OnMessageReceived(const IPC::Message& msg);
michael@0: 
michael@0:   // Like OnMessageReceived, except it only handles routed messages.  Returns
michael@0:   // true if the message was dispatched, or false if there was no listener for
michael@0:   // that route id.
michael@0:   virtual bool RouteMessage(const IPC::Message& msg);
michael@0: 
michael@0:   // IPC::Message::Sender implementation:
michael@0:   virtual bool Send(IPC::Message* msg);
michael@0: 
michael@0:   // Called to add/remove a listener for a particular message routing ID.
michael@0:   void AddRoute(int32_t routing_id, IPC::Channel::Listener* listener);
michael@0:   void RemoveRoute(int32_t routing_id);
michael@0: 
michael@0:  private:
michael@0:   // A list of all listeners with assigned routing IDs.
michael@0:   IDMap<IPC::Channel::Listener> routes_;
michael@0: 
michael@0:   DISALLOW_EVIL_CONSTRUCTORS(MessageRouter);
michael@0: };
michael@0: 
michael@0: #endif  // CHROME_COMMON_MESSAGE_ROUTER_H__