src/framework/Utilities/LinkedReference/Reference.h

   1 /*
   2  * Copyright (C) 2005-2008 MaNGOS <http://getmangos.com/>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #ifndef _REFERENCE_H
  20 #define _REFERENCE_H
  21
  22 #include "Utilities/LinkedList.h"
  23
  24 //=====================================================
  25
  26 template <class TO, class FROM> class Reference : public LinkedListElement
  27 {
  28     private:
  29         TO* iRefTo;
  30         FROM* iRefFrom;
  31     protected:
  32         // Tell our refTo (target) object that we have a link
  33         virtual void targetObjectBuildLink() = 0;
  34
  35         // Tell our refTo (taget) object, that the link is cut
  36         virtual void targetObjectDestroyLink() = 0;
  37
  38         // Tell our refFrom (source) object, that the link is cut (Target destroyed)
  39         virtual void sourceObjectDestroyLink() = 0;
  40     public:
  41         Reference() { iRefTo = NULL; iRefFrom = NULL; }
  42         virtual ~Reference() {}
  43
  44         // Create new link
  45         inline void link(TO* toObj, FROM* fromObj)
  46         {
  47             assert(fromObj);                                // fromObj MUST not be NULL
  48             if(isValid())
  49                 unlink();
  50             if(toObj != NULL)
  51             {
  52                 iRefTo = toObj;
  53                 iRefFrom = fromObj;
  54                 targetObjectBuildLink();
  55             }
  56         }
  57
  58         // We don't need the reference anymore. Call comes from the refFrom object
  59         // Tell our refTo object, that the link is cut
  60         inline void unlink() { targetObjectDestroyLink(); delink(); iRefTo = NULL; iRefFrom = NULL; }
  61
  62         // Link is invalid due to destruction of referenced target object. Call comes from the refTo object
  63         // Tell our refFrom object, that the link is cut
  64         inline void invalidate()                            // the iRefFrom MUST remain!!
  65         {
  66             sourceObjectDestroyLink(); delink(); iRefTo = NULL;
  67         }
  68
  69         inline bool isValid() const                         // Only check the iRefTo
  70         {
  71             return iRefTo != NULL;
  72         }
  73
  74         Reference<TO,FROM>* next() { return((Reference<TO,FROM>*)LinkedListElement::next()); }
  75         Reference<TO,FROM>* prev() { return((Reference<TO,FROM>*)LinkedListElement::prev()); }
  76
  77         inline TO* operator ->() const { return iRefTo; }
  78         inline TO* getTarget() const { return iRefTo; }
  79
  80         inline FROM* getSource() const { return iRefFrom; }
  81 };
  82
  83 //=====================================================
  84 #endif