libstdc++
|
00001 // Nested Exception support header (nested_exception class) for -*- C++ -*- 00002 00003 // Copyright (C) 2009-2015 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 #if __cplusplus < 201103L 00036 # include <bits/c++0x_warning.h> 00037 #else 00038 00039 #include <bits/c++config.h> 00040 00041 #if ATOMIC_INT_LOCK_FREE < 2 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() noexcept : _M_ptr(current_exception()) { } 00061 00062 nested_exception(const nested_exception&) noexcept = default; 00063 00064 nested_exception& operator=(const nested_exception&) noexcept = default; 00065 00066 virtual ~nested_exception() noexcept; 00067 00068 [[noreturn]] 00069 void 00070 rethrow_nested() const 00071 { 00072 if (_M_ptr) 00073 rethrow_exception(_M_ptr); 00074 std::terminate(); 00075 } 00076 00077 exception_ptr 00078 nested_ptr() const noexcept 00079 { return _M_ptr; } 00080 }; 00081 00082 template<typename _Except> 00083 struct _Nested_exception : public _Except, public nested_exception 00084 { 00085 explicit _Nested_exception(const _Except& __ex) 00086 : _Except(__ex) 00087 { } 00088 00089 explicit _Nested_exception(_Except&& __ex) 00090 : _Except(static_cast<_Except&&>(__ex)) 00091 { } 00092 }; 00093 00094 template<typename _Tp, 00095 bool __with_nested = !__is_base_of(nested_exception, _Tp)> 00096 struct _Throw_with_nested_impl 00097 { 00098 template<typename _Up> 00099 static void _S_throw(_Up&& __t) 00100 { throw _Nested_exception<_Tp>{static_cast<_Up&&>(__t)}; } 00101 }; 00102 00103 template<typename _Tp> 00104 struct _Throw_with_nested_impl<_Tp, false> 00105 { 00106 template<typename _Up> 00107 static void _S_throw(_Up&& __t) 00108 { throw static_cast<_Up&&>(__t); } 00109 }; 00110 00111 template<typename _Tp, bool = __is_class(_Tp) && !__is_final(_Tp)> 00112 struct _Throw_with_nested_helper : _Throw_with_nested_impl<_Tp> 00113 { }; 00114 00115 template<typename _Tp> 00116 struct _Throw_with_nested_helper<_Tp, false> 00117 : _Throw_with_nested_impl<_Tp, false> 00118 { }; 00119 00120 template<typename _Tp> 00121 struct _Throw_with_nested_helper<_Tp&, false> 00122 : _Throw_with_nested_helper<_Tp> 00123 { }; 00124 00125 template<typename _Tp> 00126 struct _Throw_with_nested_helper<_Tp&&, false> 00127 : _Throw_with_nested_helper<_Tp> 00128 { }; 00129 00130 /// If @p __t is derived from nested_exception, throws @p __t. 00131 /// Else, throws an implementation-defined object derived from both. 00132 template<typename _Tp> 00133 [[noreturn]] 00134 inline void 00135 throw_with_nested(_Tp&& __t) 00136 { 00137 _Throw_with_nested_helper<_Tp>::_S_throw(static_cast<_Tp&&>(__t)); 00138 } 00139 00140 template<typename _Tp, bool = __is_polymorphic(_Tp)> 00141 struct _Rethrow_if_nested_impl 00142 { 00143 static void _S_rethrow(const _Tp& __t) 00144 { 00145 if (auto __tp = dynamic_cast<const nested_exception*>(&__t)) 00146 __tp->rethrow_nested(); 00147 } 00148 }; 00149 00150 template<typename _Tp> 00151 struct _Rethrow_if_nested_impl<_Tp, false> 00152 { 00153 static void _S_rethrow(const _Tp&) { } 00154 }; 00155 00156 /// If @p __ex is derived from nested_exception, @p __ex.rethrow_nested(). 00157 template<typename _Ex> 00158 inline void 00159 rethrow_if_nested(const _Ex& __ex) 00160 { 00161 _Rethrow_if_nested_impl<_Ex>::_S_rethrow(__ex); 00162 } 00163 00164 // @} group exceptions 00165 } // namespace std 00166 00167 } // extern "C++" 00168 00169 #endif // C++11 00170 00171 #pragma GCC visibility pop 00172 00173 #endif // _GLIBCXX_NESTED_EXCEPTION_H