// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*- // Copyright (c) 2001-2005 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/libxorp/safe_callback_obj.hh,v 1.5 2005/03/25 02:53:44 pavlin 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: inline CallbackSafeObject() {} virtual ~CallbackSafeObject(); inline void ref_cb(SafeCallbackBase* scb); inline 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__