// Copyright (c) 2012 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 CONTENT_COMMON_MESSAGE_ROUTER_H_ #define CONTENT_COMMON_MESSAGE_ROUTER_H_ #include "base/id_map.h" #include "ipc/ipc_listener.h" #include "ipc/ipc_sender.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::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. namespace content { class MessageRouter : public IPC::Listener, public IPC::Sender { public: MessageRouter(); virtual ~MessageRouter(); // Implemented by subclasses to handle control messages virtual bool OnControlMessageReceived(const IPC::Message& msg); // IPC::Listener implementation: virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE; // 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::Sender implementation: virtual bool Send(IPC::Message* msg) OVERRIDE; // Called to add/remove a listener for a particular message routing ID. void AddRoute(int32 routing_id, IPC::Listener* listener); void RemoveRoute(int32 routing_id); private: // A list of all listeners with assigned routing IDs. IDMap<IPC::Listener> routes_; DISALLOW_COPY_AND_ASSIGN(MessageRouter); }; } // namespace content #endif // CONTENT_COMMON_MESSAGE_ROUTER_H_