1 // Nested Exception support header (nested_exception class) for -*- C++ -*- 2 3 // Copyright (C) 2009-2014 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library 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 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file bits/nested_exception.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{exception} 28 */ 29 30 #ifndef _GLIBCXX_NESTED_EXCEPTION_H 31 #define _GLIBCXX_NESTED_EXCEPTION_H 1 32 33 #pragma GCC visibility push(default) 34 35 #if __cplusplus < 201103L 36 # include <bits/c++0x_warning.h> 37 #else 38 39 #include <bits/c++config.h> 40 41 #if ATOMIC_INT_LOCK_FREE < 2 42 # error This platform does not support exception propagation. 43 #endif 44 45 extern "C++" { 46 47 namespace std 48 { 49 /** 50 * @addtogroup exceptions 51 * @{ 52 */ 53 54 /// Exception class with exception_ptr data member. 55 class nested_exception 56 { 57 exception_ptr _M_ptr; 58 59 public: 60 nested_exception() noexcept : _M_ptr(current_exception()) { } 61 62 nested_exception(const nested_exception&) = default; 63 64 nested_exception& operator=(const nested_exception&) = default; 65 66 virtual ~nested_exception() noexcept; 67 68 void 69 rethrow_nested() const __attribute__ ((__noreturn__)) 70 { rethrow_exception(_M_ptr); } 71 72 exception_ptr 73 nested_ptr() const 74 { return _M_ptr; } 75 }; 76 77 template<typename _Except> 78 struct _Nested_exception : public _Except, public nested_exception 79 { 80 explicit _Nested_exception(_Except&& __ex) 81 : _Except(static_cast<_Except&&>(__ex)) 82 { } 83 }; 84 85 template<typename _Ex> 86 struct __get_nested_helper 87 { 88 static const nested_exception* 89 _S_get(const _Ex& __ex) 90 { return dynamic_cast<const nested_exception*>(&__ex); } 91 }; 92 93 template<typename _Ex> 94 struct __get_nested_helper<_Ex*> 95 { 96 static const nested_exception* 97 _S_get(const _Ex* __ex) 98 { return dynamic_cast<const nested_exception*>(__ex); } 99 }; 100 101 template<typename _Ex> 102 inline const nested_exception* 103 __get_nested_exception(const _Ex& __ex) 104 { return __get_nested_helper<_Ex>::_S_get(__ex); } 105 106 template<typename _Ex> 107 void 108 __throw_with_nested(_Ex&&, const nested_exception* = 0) 109 __attribute__ ((__noreturn__)); 110 111 template<typename _Ex> 112 void 113 __throw_with_nested(_Ex&&, ...) __attribute__ ((__noreturn__)); 114 115 // This function should never be called, but is needed to avoid a warning 116 // about ambiguous base classes when instantiating throw_with_nested<_Ex>() 117 // with a type that has an accessible nested_exception base. 118 template<typename _Ex> 119 inline void 120 __throw_with_nested(_Ex&& __ex, const nested_exception*) 121 { throw __ex; } 122 123 template<typename _Ex> 124 inline void 125 __throw_with_nested(_Ex&& __ex, ...) 126 { throw _Nested_exception<_Ex>(static_cast<_Ex&&>(__ex)); } 127 128 template<typename _Ex> 129 void 130 throw_with_nested(_Ex __ex) __attribute__ ((__noreturn__)); 131 132 /// If @p __ex is derived from nested_exception, @p __ex. 133 /// Else, an implementation-defined object derived from both. 134 template<typename _Ex> 135 inline void 136 throw_with_nested(_Ex __ex) 137 { 138 if (__get_nested_exception(__ex)) 139 throw __ex; 140 __throw_with_nested(static_cast<_Ex&&>(__ex), &__ex); 141 } 142 143 /// If @p __ex is derived from nested_exception, @p __ex.rethrow_nested(). 144 template<typename _Ex> 145 inline void 146 rethrow_if_nested(const _Ex& __ex) 147 { 148 if (const nested_exception* __nested = __get_nested_exception(__ex)) 149 __nested->rethrow_nested(); 150 } 151 152 /// Overload, See N2619 153 inline void 154 rethrow_if_nested(const nested_exception& __ex) 155 { __ex.rethrow_nested(); } 156 157 // @} group exceptions 158 } // namespace std 159 160 } // extern "C++" 161 162 #endif // C++11 163 164 #pragma GCC visibility pop 165 166 #endif // _GLIBCXX_NESTED_EXCEPTION_H 167
