Source: ../../libxipc/finder_client.hh
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// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// Copyright (c) 2001-2003 International Computer Science Institute
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software")
// to deal in the Software without restriction, subject to the conditions
// listed in the XORP LICENSE file. These conditions include: you must
// preserve this copyright notice, and you cannot mention the copyright
// holders in advertising related to the Software without their permission.
// The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
// notice is a summary of the XORP LICENSE file; the license in that file is
// legally binding.
// $XORP: xorp/libxipc/finder_client.hh,v 1.12 2003/06/19 19:20:07 hodson Exp $
#ifndef __LIBXIPC_FINDER_CLIENT_HH__
#define __LIBXIPC_FINDER_CLIENT_HH__
#include <list>
#include <map>
#include <string>
#include "finder_client_base.hh"
#include "finder_messenger.hh"
#include "xrl_pf.hh"
class FinderClientOp;
class FinderClientObserver;
/**
* A one-to-many container used by the FinderClient to store
* unresolved-to-resolved Xrl mappings.
*/
struct FinderDBEntry
{
FinderDBEntry(const string& key);
FinderDBEntry(const string& key, const string& value);
inline const string& key() const { return _key; }
inline const list<string>& values() const { return _values; }
inline list<string>& values() { return _values; }
inline void clear();
protected:
string _key;
list<string> _values;
};
/**
* Interface class for FinderClient Xrl requests.
*
* The methods in this interface are implemented by the FinderClient
* to handle its XRL requests. It exists as a separate class to restrict
* the operations that the XRL interface can invoke.
*/
class FinderClientXrlCommandInterface
{
public:
virtual void uncache_xrl(const string& xrl) = 0;
virtual void uncache_xrls_from_target(const string& target) = 0;
virtual XrlCmdError dispatch_tunneled_xrl(const string& xrl) = 0;
};
/**
* @short Class that represents clients of the Finder.
*
* The FinderClient class performs communication processing with the
* Finder on behalf of XORP processes. It handles XRL registration
* and resolution requests.
*/
class FinderClient :
public FinderMessengerManager, public FinderClientXrlCommandInterface
{
public:
typedef
XorpCallback2<void, const XrlError&, const FinderDBEntry*>::RefPtr
QueryCallback;
typedef ref_ptr<FinderClientOp> Operation;
typedef list<Operation> OperationQueue;
class InstanceInfo;
typedef map<string, FinderDBEntry> ResolvedTable;
typedef map<string, string> LocalResolvedTable;
typedef vector<InstanceInfo> InstanceList;
public:
/**
* Constructor.
*/
FinderClient();
/**
* Destructor.
*/
virtual ~FinderClient();
/**
* Register an Xrl Target with the FinderClient and place request with
* Finder to perform registration. The request to the Finder is
* asynchronous and there is a delay between when the request is made
* when it is satisfied.
*
* @param instance_name a unique name to be associated with the Target.
* @param class_name the class name that the Target is an instance of.
* @param dispatcher pointer to Xrl dispatcher that can execute the
* command.
*
* @return true on success, false if @ref instance_name or @ref
* class_name are empty.
*/
bool register_xrl_target(const string& instance_name,
const string& class_name,
const XrlDispatcher* dispatcher);
/**
* Unregister Xrl Target with FinderClient and place a request with
* the Finder to remove registration. The request to the Finder is
* asynchronous and there is a delay between when the request is made
* when it is satisfied.
*
* @param instance_name unique name associated with Xrl Target.
*/
bool unregister_xrl_target(const string& instance_name);
/**
* Register an Xrl with the Finder.
*
* @param instance_name unique name associated with Xrl Target and making
* the registration.
*
* @param xrl string representation of the Xrl.
* @param pf_name protocol family name that implements Xrl.
* @param pf_args protocol family arguments to locate dispatcher for
* registered Xrl.
*
* @return true if registration request is successfully enqueued, false
* otherwise.
*/
bool register_xrl(const string& instance_name,
const string& xrl,
const string& pf_name,
const string& pf_args);
/**
* Request Finder advertise Xrls associated with an Xrl Target instance
* to other XORP Xrl targets. Until the Finder has satisfied this
* request the Xrl Target has no visibility in the Xrl universe.
*
* @param instance_name unique name associated with Xrl Target to
* be advertised.
*
* @return true on success, false if instance_name has not previously
* been registered with FinderClient.
*/
bool enable_xrls(const string& instance_name);
/**
* Request resolution of an Xrl.
*
* If the Xrl to be resolved in cache exists in the FinderClients
* cache, the callback provided as a function argument is invoked
* immediately. Otherwise the request is forwarded to the finder,
* the cache updated, and callback dispatched when the Finder
* answers the request.
*
* @param xrl Xrl to be resolved.
* @param qcb callback to be dispatched when result is availble.
*/
void query(const string& xrl,
const QueryCallback& qcb);
/**
* Attempt to resolve Xrl from cache.
*
* @param xrl Xrl to be resolved.
*
* @return pointer to cached entry on success, 0 otherwise.
*/
const FinderDBEntry* query_cache(const string& xrl) const;
/**
* Resolve Xrl that an Xrl Target associated with the FinderClient
* registered.
*
* @param incoming_xrl_command the command component of the Xrl being
* resolved.
* @param local_xrl_command the local name of the Xrl command being
* resolved.
* @return true and assign value to local_xrl_command on success, false
* on failure.
*/
bool query_self(const string& incoming_xrl_command,
string& local_xrl_command) const;
/**
* Send an Xrl for the Finder to dispatch. This is the mechanism
* that allows clients of the Finder to interrogate the Finder through
* an Xrl interface.
*
* @param x Xrl to be dispatched.
* @param cb callback to be called with dispatch result.
* @return true on success.
*/
bool forward_finder_xrl(const Xrl& x, const XrlPFSender::SendCallback& cb);
/**
* Accessor for Finder Messenger used by FinderClient instance.
*/
FinderMessengerBase* messenger();
/**
* Get list of operations pending.
*/
inline OperationQueue& todo_list() { return _todo_list; }
/**
* Get List of operations done and are repeatable.
*/
inline OperationQueue& done_list() { return _done_list; }
/**
* Notify successful completion of an operation on the todo list.
*/
void notify_done(const FinderClientOp* completed);
/**
* Notify failed completion of an operation on the todo list.
*/
void notify_failed(const FinderClientOp* completed);
/**
* Get the Xrl Commands implemented by the FinderClient.
*/
inline XrlCmdMap& commands() { return _commands; }
/**
* @return true if FinderClient has registered Xrls and is considered
* operational.
*/
inline bool ready() const { return _xrls_registered; }
/**
* @return true if a connection is established with the Finder.
*/
inline bool connected() const { return _messenger != 0; }
/**
* Attach a FinderClientObserver instance to receive event notifications.
*
* @param o pointer to observer to receive notifications.
*
* @return true on success, false if an observer is already present.
*/
bool attach_observer(FinderClientObserver* o);
/**
* Detach the FinderClientObserver instance.
*
* @param o pointer to the FinderClientObserver be removed.
*
* @return true on success, false if the FinderClientObserver
* is not the current observer.
*/
bool detach_observer(FinderClientObserver* o);
protected:
// FinderMessengerManager interface
void messenger_birth_event(FinderMessengerBase*);
void messenger_death_event(FinderMessengerBase*);
void messenger_active_event(FinderMessengerBase*);
void messenger_inactive_event(FinderMessengerBase*);
void messenger_stopped_event(FinderMessengerBase*);
bool manages(const FinderMessengerBase*) const;
protected:
// FinderClientXrlCommandInterface
void uncache_xrl(const string& xrl);
void uncache_xrls_from_target(const string& target);
XrlCmdError dispatch_tunneled_xrl(const string& xrl);
protected:
void crank();
void prepare_for_restart();
protected:
inline InstanceList::iterator find_instance(const string& instance);
inline InstanceList::const_iterator find_instance(const string& instance) const;
protected:
OperationQueue _todo_list;
OperationQueue _done_list;
ResolvedTable _rt;
LocalResolvedTable _lrt;
InstanceList _ids;
XrlCmdMap _commands;
FinderMessengerBase* _messenger;
bool _pending_result;
bool _xrls_registered;
FinderClientObserver* _observer;
};
#endif // __LIBXIPC_FINDER_CLIENT_HH__
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