libstdc++
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00001 // Nested Exception support header (nested_exception class) for -*- C++ -*- 00002 00003 // Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file bits/nested_exception.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{exception} 00028 */ 00029 00030 #ifndef _GLIBCXX_NESTED_EXCEPTION_H 00031 #define _GLIBCXX_NESTED_EXCEPTION_H 1 00032 00033 #pragma GCC visibility push(default) 00034 00035 #ifndef __GXX_EXPERIMENTAL_CXX0X__ 00036 # include <bits/c++0x_warning.h> 00037 #else 00038 00039 #include <bits/c++config.h> 00040 00041 #if !defined(_GLIBCXX_ATOMIC_BUILTINS_4) 00042 # error This platform does not support exception propagation. 00043 #endif 00044 00045 extern "C++" { 00046 00047 namespace std 00048 { 00049 /** 00050 * @addtogroup exceptions 00051 * @{ 00052 */ 00053 00054 /// Exception class with exception_ptr data member. 00055 class nested_exception 00056 { 00057 exception_ptr _M_ptr; 00058 00059 public: 00060 nested_exception() throw() : _M_ptr(current_exception()) { } 00061 00062 nested_exception(const nested_exception&) = default; 00063 00064 nested_exception& operator=(const nested_exception&) = default; 00065 00066 inline virtual ~nested_exception(); 00067 00068 void 00069 rethrow_nested() const __attribute__ ((__noreturn__)) 00070 { rethrow_exception(_M_ptr); } 00071 00072 exception_ptr 00073 nested_ptr() const 00074 { return _M_ptr; } 00075 }; 00076 00077 inline nested_exception::~nested_exception() = default; 00078 00079 template<typename _Except> 00080 struct _Nested_exception : public _Except, public nested_exception 00081 { 00082 explicit _Nested_exception(_Except&& __ex) 00083 : _Except(static_cast<_Except&&>(__ex)) 00084 { } 00085 }; 00086 00087 template<typename _Ex> 00088 struct __get_nested_helper 00089 { 00090 static const nested_exception* 00091 _S_get(const _Ex& __ex) 00092 { return dynamic_cast<const nested_exception*>(&__ex); } 00093 }; 00094 00095 template<typename _Ex> 00096 struct __get_nested_helper<_Ex*> 00097 { 00098 static const nested_exception* 00099 _S_get(const _Ex* __ex) 00100 { return dynamic_cast<const nested_exception*>(__ex); } 00101 }; 00102 00103 template<typename _Ex> 00104 inline const nested_exception* 00105 __get_nested_exception(const _Ex& __ex) 00106 { return __get_nested_helper<_Ex>::_S_get(__ex); } 00107 00108 template<typename _Ex> 00109 void 00110 __throw_with_nested(_Ex&&, const nested_exception* = 0) 00111 __attribute__ ((__noreturn__)); 00112 00113 template<typename _Ex> 00114 void 00115 __throw_with_nested(_Ex&&, ...) __attribute__ ((__noreturn__)); 00116 00117 // This function should never be called, but is needed to avoid a warning 00118 // about ambiguous base classes when instantiating throw_with_nested<_Ex>() 00119 // with a type that has an accessible nested_exception base. 00120 template<typename _Ex> 00121 inline void 00122 __throw_with_nested(_Ex&& __ex, const nested_exception* = 0) 00123 { throw __ex; } 00124 00125 template<typename _Ex> 00126 inline void 00127 __throw_with_nested(_Ex&& __ex, ...) 00128 { throw _Nested_exception<_Ex>(static_cast<_Ex&&>(__ex)); } 00129 00130 template<typename _Ex> 00131 void 00132 throw_with_nested(_Ex __ex) __attribute__ ((__noreturn__)); 00133 00134 /// If @p __ex is derived from nested_exception, @p __ex. 00135 /// Else, an implementation-defined object derived from both. 00136 template<typename _Ex> 00137 inline void 00138 throw_with_nested(_Ex __ex) 00139 { 00140 if (__get_nested_exception(__ex)) 00141 throw __ex; 00142 __throw_with_nested(static_cast<_Ex&&>(__ex), &__ex); 00143 } 00144 00145 /// If @p __ex is derived from nested_exception, @p __ex.rethrow_nested(). 00146 template<typename _Ex> 00147 inline void 00148 rethrow_if_nested(const _Ex& __ex) 00149 { 00150 if (const nested_exception* __nested = __get_nested_exception(__ex)) 00151 __nested->rethrow_nested(); 00152 } 00153 00154 /// Overload, See N2619 00155 inline void 00156 rethrow_if_nested(const nested_exception& __ex) 00157 { __ex.rethrow_nested(); } 00158 00159 // @} group exceptions 00160 } // namespace std 00161 00162 } // extern "C++" 00163 00164 #endif // __GXX_EXPERIMENTAL_CXX0X__ 00165 00166 #pragma GCC visibility pop 00167 00168 #endif // _GLIBCXX_NESTED_EXCEPTION_H