// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*- // vim:set sts=4 ts=8: // Copyright (c) 2001-2006 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/policy/backend/version_filter.hh,v 1.3 2006/03/16 00:05:12 pavlin Exp $ #ifndef __POLICY_BACKEND_VERSION_FILTER_HH__ #define __POLICY_BACKEND_VERSION_FILTER_HH__ #include "policy/common/varrw.hh" #include "filter_base.hh" #include "policy_filter.hh" /** * @short Policy filters which support versioning [i.e. keep old version]. * * The idea is to create a new policy filter on each configuration. Whenever a * route is being processed, you read which filter to run. If this filter is 0, * [null pointer] then give it the last configuration. Else just run whatever * filter is returned. * * Filters should be referenced counted by routes. When reference count reaches * 0, it should be deleted. * * Why not keep filters internally here and read a filter id from route? Well * because we cannot assume when to increment and decrement the reference count. * Say it's a normal route lookup and we do the filtering, and it results to * "accepted". It doesn't imply we need to +1 the reference count. */ class VersionFilter : public FilterBase { public: /** * @param fname the variable to read/write in order to access filter. */ VersionFilter(const VarRW::Id& fname); ~VersionFilter(); /** * Configure the filter * * @param str filter configuration. */ void configure(const string& str); /** * Reset the filter. * * Filter becomes a NO-operation -- default action should * be returned everytime an acceptRoute is called. */ void reset(); /** * See if a route is accepted by the filter. * The route may be modified by the filter [through VarRW]. * * @return true if the route is accepted, false otherwise. * @param varrw the VarRW associated with the route being filtered. */ bool acceptRoute(VarRW& varrw); private: RefPf _filter; VarRW::Id _fname; }; #endif // __POLICY_BACKEND_VERSION_FILTER_HH__