// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*- // Copyright (c) 2001-2009 XORP, Inc. // // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License, Version // 2.1, June 1999 as published by the Free Software Foundation. // Redistribution and/or modification of this program under the terms of // any other version of the GNU Lesser General Public License is not // permitted. // // This program is distributed in the hope that it will be useful, but // WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For more details, // see the GNU Lesser General Public License, Version 2.1, a copy of // which can be found in the XORP LICENSE.lgpl file. // // XORP, Inc, 2953 Bunker Hill Lane, Suite 204, Santa Clara, CA 95054, USA; // http://xorp.net // $XORP: xorp/libxorp/safe_callback_obj.hh,v 1.12 2009/01/05 18:30:58 jtc Exp $ #ifndef __LIBXORP_SAFE_CALLBACK_OBJ_HH__ #define __LIBXORP_SAFE_CALLBACK_OBJ_HH__ #include <algorithm> #include <vector> struct SafeCallbackBase; /** * @short Base class for objects that are callback safe. * * Objects that wish to be callback safe should be derived from this * class. The class works in conjunction with SafeCallbackBase and * between them implement callback and callback-object tracking. When * a CallbackSafeObject is destructed it informs all the callbacks that * refer to it that this is the case and invalidates (sets to null) * the object they point to. */ class CallbackSafeObject { public: CallbackSafeObject() {} virtual ~CallbackSafeObject(); void ref_cb(SafeCallbackBase* scb); void unref_cb(SafeCallbackBase* scb); protected: // Copy operations are not supported. It's hard to know what the // correct thing to do on assignment or copy, so best bet is not // to do anything. CallbackSafeObject(const CallbackSafeObject&); // Not implemented CallbackSafeObject& operator=(const CallbackSafeObject&); // Not implemented protected: std::vector<SafeCallbackBase*> _cbs; }; /** * @short Base class for safe callbacks. * * These are object callbacks that are only dispatched if target of * callback is non-null. */ class SafeCallbackBase { public: /** * Constructor. * * Informs CallbackSafeObject that this callback operates on it. */ SafeCallbackBase(CallbackSafeObject* o); /** * Destructor. * * Informs CallbackSafeObject that is tracking callback * instances that this callback no longer exists. */ ~SafeCallbackBase(); void invalidate(); bool valid() const; protected: SafeCallbackBase(); // Not implemented SafeCallbackBase(const SafeCallbackBase&); // Not implemented SafeCallbackBase& operator=(const SafeCallbackBase&); // Not implemented CallbackSafeObject* _cso; }; // ---------------------------------------------------------------------------- // Inline CallbackSafeObject methods inline void CallbackSafeObject::ref_cb(SafeCallbackBase* scb) { _cbs.push_back(scb); } inline void CallbackSafeObject::unref_cb(SafeCallbackBase* scb) { std::vector<SafeCallbackBase*>::iterator i = find(_cbs.begin(), _cbs.end(), scb); if (i != _cbs.end()) _cbs.erase(i); } #endif // __LIBXORP_SAFE_CALLBACK_OBJ_HH__