src/shared/Singleton.h

   1 /* Singleton.h
   2  *
   3  * Copyright (C) 2004 Wow Daemon
   4  * Copyright (C) 2005 MaNGOS <https://opensvn.csie.org/traccgi/MaNGOS/trac.cgi/>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #ifndef MANGOSSERVER_SINGLETON_H
  22 #define MANGOSSERVER_SINGLETON_H
  23
  24 #include "Errors.h"
  25
  26 /// Should be placed in the appropriate .cpp file somewhere
  27 #define initialiseSingleton( type ) \
  28 template <> type * Singleton < type > :: mSingleton = 0
  29
  30 /// To be used as a replacement for initialiseSingleton( )
  31 ///  Creates a file-scoped Singleton object, to be retrieved with getSingleton
  32 #define createFileSingleton( type ) \
  33 initialiseSingleton( type ); \
  34 type the##type
  35
  36 template < class type > class Singleton
  37 {
  38     public:
  39         /// Constructor
  40         Singleton( )
  41         {
  42                WPAssert( mSingleton == 0 );
  43             mSingleton = static_cast<type *>(this);
  44         }
  45         /// Destructor
  46         ~Singleton( )
  47         {
  48             mSingleton = 0;
  49         }
  50
  51         /// Retrieve the singleton object, if you hit this assert this singleton object doesn't exist yet
  52         static type & getSingleton( ) { WPAssert( mSingleton ); return *mSingleton; }
  53
  54         /// Retrieve a pointer to the singleton object
  55         static type * getSingletonPtr( ) { return mSingleton; }
  56
  57     protected:
  58         /// Singleton pointer, must be set to 0 prior to creating the object
  59         static type * mSingleton;
  60 };
  61 #endif