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- // 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 IPC_MESSAGE_ROUTER_H_
- #define IPC_MESSAGE_ROUTER_H_
- #include <stdint.h>
- #include "base/component_export.h"
- #include "base/containers/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 IPC {
- class COMPONENT_EXPORT(IPC) MessageRouter : public Listener, public Sender {
- public:
- MessageRouter();
- MessageRouter(const MessageRouter&) = delete;
- MessageRouter& operator=(const MessageRouter&) = delete;
- ~MessageRouter() override;
- // Implemented by subclasses to handle control messages
- virtual bool OnControlMessageReceived(const Message& msg);
- // Listener implementation:
- bool OnMessageReceived(const 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 Message& msg);
- // Sender implementation:
- bool Send(Message* msg) override;
- // Called to add a listener for a particular message routing ID.
- // Returns true if succeeded.
- bool AddRoute(int32_t routing_id, Listener* listener);
- // Called to remove a listener for a particular message routing ID.
- void RemoveRoute(int32_t routing_id);
- // Returns the Listener associated with |routing_id|.
- Listener* GetRoute(int32_t routing_id);
- private:
- // A list of all listeners with assigned routing IDs.
- base::IDMap<Listener*> routes_;
- };
- } // namespace IPC
- #endif // IPC_MESSAGE_ROUTER_H_
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