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// Nested Exception support header (nested_exception class) for -*- C++ -*- |
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// Copyright (C) 2009-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the |
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// terms of the GNU General Public License as published by the |
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// Free Software Foundation; either version 3, or (at your option) |
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// any later version. |
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|
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// This library is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/** @file bits/nested_exception.h |
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* This is an internal header file, included by other library headers. |
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* Do not attempt to use it directly. @headername{exception} |
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*/ |
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|
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#ifndef _GLIBCXX_NESTED_EXCEPTION_H |
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#define _GLIBCXX_NESTED_EXCEPTION_H 1 |
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|
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#pragma GCC visibility push(default) |
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|
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#if __cplusplus < 201103L |
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# include <bits/c++0x_warning.h> |
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#else |
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|
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#include <bits/c++config.h> |
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#include <bits/move.h> |
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|
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extern "C++" { |
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|
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namespace std |
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{ |
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/** |
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* @addtogroup exceptions |
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* @{ |
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*/ |
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|
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/// Exception class with exception_ptr data member. |
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class nested_exception |
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{ |
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exception_ptr _M_ptr; |
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|
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public: |
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nested_exception() noexcept : _M_ptr(current_exception()) { } |
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|
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nested_exception(const nested_exception&) noexcept = default; |
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|
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nested_exception& operator=(const nested_exception&) noexcept = default; |
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|
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virtual ~nested_exception() noexcept; |
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|
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[[noreturn]] |
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void |
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rethrow_nested() const |
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{ |
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if (_M_ptr) |
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rethrow_exception(_M_ptr); |
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std::terminate(); |
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} |
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|
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exception_ptr |
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nested_ptr() const noexcept |
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{ return _M_ptr; } |
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}; |
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|
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/// @cond undocumented |
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|
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template<typename _Except> |
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struct _Nested_exception : public _Except, public nested_exception |
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{ |
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explicit _Nested_exception(const _Except& __ex) |
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: _Except(__ex) |
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{ } |
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|
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explicit _Nested_exception(_Except&& __ex) |
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: _Except(static_cast<_Except&&>(__ex)) |
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{ } |
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}; |
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|
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// [except.nested]/8 |
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// Throw an exception of unspecified type that is publicly derived from |
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// both remove_reference_t<_Tp> and nested_exception. |
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template<typename _Tp> |
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[[noreturn]] |
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inline void |
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__throw_with_nested_impl(_Tp&& __t, true_type) |
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{ |
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using _Up = typename remove_reference<_Tp>::type; |
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throw _Nested_exception<_Up>{std::forward<_Tp>(__t)}; |
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} |
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|
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template<typename _Tp> |
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[[noreturn]] |
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inline void |
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__throw_with_nested_impl(_Tp&& __t, false_type) |
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{ throw std::forward<_Tp>(__t); } |
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|
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/// @endcond |
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|
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/// If @p __t is derived from nested_exception, throws @p __t. |
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/// Else, throws an implementation-defined object derived from both. |
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template<typename _Tp> |
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[[noreturn]] |
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inline void |
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throw_with_nested(_Tp&& __t) |
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{ |
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using _Up = typename decay<_Tp>::type; |
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using _CopyConstructible |
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= __and_<is_copy_constructible<_Up>, is_move_constructible<_Up>>; |
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static_assert(_CopyConstructible::value, |
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"throw_with_nested argument must be CopyConstructible"); |
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using __nest = __and_<is_class<_Up>, __bool_constant<!__is_final(_Up)>, |
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__not_<is_base_of<nested_exception, _Up>>>; |
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std::__throw_with_nested_impl(std::forward<_Tp>(__t), __nest{}); |
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} |
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|
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/// @cond undocumented |
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|
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// Determine if dynamic_cast<const nested_exception&> would be well-formed. |
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template<typename _Tp> |
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using __rethrow_if_nested_cond = typename enable_if< |
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__and_<is_polymorphic<_Tp>, |
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__or_<__not_<is_base_of<nested_exception, _Tp>>, |
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is_convertible<_Tp*, nested_exception*>>>::value |
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>::type; |
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|
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// Attempt dynamic_cast to nested_exception and call rethrow_nested(). |
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template<typename _Ex> |
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inline __rethrow_if_nested_cond<_Ex> |
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__rethrow_if_nested_impl(const _Ex* __ptr) |
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{ |
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if (auto __ne_ptr = dynamic_cast<const nested_exception*>(__ptr)) |
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__ne_ptr->rethrow_nested(); |
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} |
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|
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// Otherwise, no effects. |
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inline void |
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__rethrow_if_nested_impl(const void*) |
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{ } |
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|
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/// @endcond |
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|
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/// If @p __ex is derived from nested_exception, @p __ex.rethrow_nested(). |
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template<typename _Ex> |
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inline void |
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rethrow_if_nested(const _Ex& __ex) |
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{ std::__rethrow_if_nested_impl(std::__addressof(__ex)); } |
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|
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/// @} group exceptions |
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} // namespace std |
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|
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} // extern "C++" |
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|
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#endif // C++11 |
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#pragma GCC visibility pop |
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|
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#endif // _GLIBCXX_NESTED_EXCEPTION_H |
