apt-pkg/contrib/weakptr.h

   1 /* weakptr.h - An object which supports weak pointers.
   2  *
   3  * Copyright (C) 2010 Julian Andres Klode <jak@debian.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  18  * MA 02110-1301, USA.
  19  */
  20
  21 #ifndef WEAK_POINTER_H
  22 #define WEAK_POINTER_H
  23
  24 #include <cstdlib>
  25 #include <set>
  26 /**
  27  * Class for objects providing support for weak pointers.
  28  *
  29  * This class allows for the registration of certain pointers as weak,
  30  * which will cause them to be set to NULL when the destructor of the
  31  * object is called.
  32  */
  33 class WeakPointable {
  34 private:
  35     std::set<WeakPointable**> pointers;
  36
  37 public:
  38
  39     /**
  40      * Add a new weak pointer.
  41      */
  42     inline void AddWeakPointer(WeakPointable** weakptr) {
  43        pointers.insert(weakptr);
  44     }
  45
  46     /**
  47      * Remove the weak pointer from the list of weak pointers.
  48      */
  49     inline void RemoveWeakPointer(WeakPointable **weakptr) {
  50        pointers.erase(weakptr);
  51     }
  52
  53     /**
  54      * Deconstruct the object, set all weak pointers to NULL.
  55      */
  56     ~WeakPointable() {
  57         std::set<WeakPointable**>::iterator iter = pointers.begin();
  58         while (iter != pointers.end())
  59             **(iter++) = NULL;
  60     }
  61 };
  62
  63 #endif // WEAK_POINTER_H