00001 /* 00002 * IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING. By 00003 * downloading, copying, installing or using the software you agree to 00004 * this license. If you do not agree to this license, do not download, 00005 * install, copy or use the software. 00006 * 00007 * Intel Open Source License 00008 * 00009 * Copyright (c) 2004 Intel Corporation. All rights reserved. 00010 * 00011 * Redistribution and use in source and binary forms, with or without 00012 * modification, are permitted provided that the following conditions are 00013 * met: 00014 * 00015 * Redistributions of source code must retain the above copyright 00016 * notice, this list of conditions and the following disclaimer. 00017 * 00018 * Redistributions in binary form must reproduce the above copyright 00019 * notice, this list of conditions and the following disclaimer in the 00020 * documentation and/or other materials provided with the distribution. 00021 * 00022 * Neither the name of the Intel Corporation nor the names of its 00023 * contributors may be used to endorse or promote products derived from 00024 * this software without specific prior written permission. 00025 * 00026 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00027 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00028 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 00029 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE INTEL OR 00030 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00031 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00032 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00033 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00034 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00035 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 00036 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00037 */ 00038 #ifndef __SINGLETON_H__ 00039 #define __SINGLETON_H__ 00040 00041 #include "../debug/DebugUtils.h" 00042 00043 namespace oasys { 00044 00060 template<typename _Class, bool _auto_create = true> 00061 class Singleton; 00062 00063 // Autocreation of the singleton 00064 template<typename _Class> 00065 class Singleton<_Class, true> { 00066 public: 00067 static _Class* instance() { 00068 // XXX/demmer this has potential race conditions if multiple 00069 // threads try to access the singleton for the first time 00070 00071 if(instance_ == 0) { 00072 instance_ = new _Class(); 00073 } 00074 ASSERT(instance_); 00075 00076 return instance_; 00077 } 00078 00079 static _Class* create() { 00080 if (instance_) { 00081 PANIC("Singleton create() method called more than once"); 00082 } 00083 00084 instance_ = new _Class(); 00085 return instance_; 00086 } 00087 00088 static void set_instance(_Class* instance) { 00089 if (instance_) { 00090 PANIC("Singleton set_instance() called with existing object"); 00091 } 00092 instance_ = instance; 00093 } 00094 00095 protected: 00096 static _Class* instance_; 00097 }; 00098 00099 // No autocreation of the instance 00100 template<typename _Class> 00101 class Singleton<_Class, false> { 00102 public: 00103 static _Class* instance() 00104 { 00105 // XXX/demmer this has potential race conditions if multiple 00106 // threads try to access the singleton for the first time 00107 ASSERT(instance_); 00108 return instance_; 00109 } 00110 00111 static _Class* create() 00112 { 00113 if (instance_) 00114 { 00115 PANIC("Singleton create() method called more than once"); 00116 } 00117 00118 instance_ = new _Class(); 00119 return instance_; 00120 } 00121 00122 static void set_instance(_Class* instance) 00123 { 00124 if (instance_) 00125 { 00126 PANIC("Singleton set_instance() called with existing object"); 00127 } 00128 instance_ = instance; 00129 } 00130 00131 protected: 00132 static _Class* instance_; 00133 }; 00134 00145 template<typename _Class> 00146 class SingletonRef { 00147 public: 00148 _Class* operator->() { 00149 return Singleton<_Class>::instance(); 00150 } 00151 }; 00152 00153 } // namespace oasys 00154 00155 #endif // __SINGLETON_H__