00001 // Copyright (C) 2001 Open Source Telecom Corporation. 00002 // 00003 // This program is free software; you can redistribute it and/or modify 00004 // it under the terms of the GNU General Public License as published by 00005 // the Free Software Foundation; either version 2 of the License, or 00006 // (at your option) any later version. 00007 // 00008 // This program is distributed in the hope that it will be useful, 00009 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00010 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00011 // GNU General Public License for more details. 00012 // 00013 // You should have received a copy of the GNU General Public License 00014 // along with this program; if not, write to the Free Software 00015 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 00016 // 00017 // As a special exception to the GNU General Public License, permission is 00018 // granted for additional uses of the text contained in its release 00019 // of Common C++. 00020 // 00021 // The exception is that, if you link the Common C++ library with other 00022 // files to produce an executable, this does not by itself cause the 00023 // resulting executable to be covered by the GNU General Public License. 00024 // Your use of that executable is in no way restricted on account of 00025 // linking the Common C++ library code into it. 00026 // 00027 // This exception does not however invalidate any other reasons why 00028 // the executable file might be covered by the GNU General Public License. 00029 // 00030 // This exception applies only to the code released under the 00031 // name Common C++. If you copy code from other releases into a copy of 00032 // Common C++, as the General Public License permits, the exception does 00033 // not apply to the code that you add in this way. To avoid misleading 00034 // anyone as to the status of such modified files, you must delete 00035 // this exception notice from them. 00036 // 00037 // If you write modifications of your own for Common C++, it is your choice 00038 // whether to permit this exception to apply to your modifications. 00039 // If you do not wish that, delete this exception notice. 00040 00041 namespace ost { 00042 00043 template <class T> 00044 class Instance : private RWLock 00045 { 00046 protected: 00047 static T* objPointer; 00048 unsigned objCount; 00049 bool objPurge; 00050 00051 Instance() 00052 { 00053 WriteLock(); 00054 if(objPointer) 00055 { 00056 if(objPointer->objCount) 00057 objPointer->objPurge = true; 00058 else 00059 delete objPointer; 00060 } 00061 objPointer = this; 00062 objCount = 0; 00063 objPurge = false; 00064 Unlock(); 00065 } 00066 public: 00067 static T *getInstance(void); 00068 00069 void endInstance() 00070 { 00071 --objcount; 00072 if(!objCount && objPurge) 00073 delete this; 00074 } 00075 }; 00076 00077 template <class T> 00078 T *Instance<T>::objPointer = NULL; 00079 00080 template <class T> 00081 T *Instance<T>::getInstance(void) 00082 { 00083 Instance<T> *ptr; 00084 ReadLock(); 00085 ptr = Instance<T>::objPointer; 00086 ptr->objCount++; 00087 Unlock(); 00088 return <T *>ptr; 00089 } 00090 00091 00092 };