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127 lines
4.6 KiB
C++
127 lines
4.6 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___EXPECTED_UNEXPECTED_H
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#define _LIBCPP___EXPECTED_UNEXPECTED_H
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#include <__config>
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#include <__type_traits/conjunction.h>
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#include <__type_traits/is_array.h>
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#include <__type_traits/is_const.h>
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#include <__type_traits/is_constructible.h>
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#include <__type_traits/is_nothrow_constructible.h>
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#include <__type_traits/is_object.h>
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#include <__type_traits/is_same.h>
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#include <__type_traits/is_swappable.h>
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#include <__type_traits/is_volatile.h>
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#include <__type_traits/negation.h>
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#include <__type_traits/remove_cvref.h>
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#include <__utility/forward.h>
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#include <__utility/in_place.h>
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#include <__utility/move.h>
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#include <__utility/swap.h>
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#include <initializer_list>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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#if _LIBCPP_STD_VER >= 23
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Err>
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class unexpected;
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template <class _Tp>
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struct __is_std_unexpected : false_type {};
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template <class _Err>
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struct __is_std_unexpected<unexpected<_Err>> : true_type {};
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template <class _Tp>
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using __valid_std_unexpected = _BoolConstant< //
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is_object_v<_Tp> && //
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!is_array_v<_Tp> && //
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!__is_std_unexpected<_Tp>::value && //
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!is_const_v<_Tp> && //
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!is_volatile_v<_Tp> //
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>;
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template <class _Err>
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class unexpected {
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static_assert(__valid_std_unexpected<_Err>::value,
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"[expected.un.general] states a program that instantiates std::unexpected for a non-object type, an "
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"array type, a specialization of unexpected, or a cv-qualified type is ill-formed.");
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public:
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_LIBCPP_HIDE_FROM_ABI constexpr unexpected(const unexpected&) = default;
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_LIBCPP_HIDE_FROM_ABI constexpr unexpected(unexpected&&) = default;
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template <class _Error = _Err>
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requires(!is_same_v<remove_cvref_t<_Error>, unexpected> && //
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!is_same_v<remove_cvref_t<_Error>, in_place_t> && //
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is_constructible_v<_Err, _Error>)
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_LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(_Error&& __error) //
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noexcept(is_nothrow_constructible_v<_Err, _Error>) // strengthened
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: __unex_(std::forward<_Error>(__error)) {}
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template <class... _Args>
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requires is_constructible_v<_Err, _Args...>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(in_place_t, _Args&&... __args) //
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noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened
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: __unex_(std::forward<_Args>(__args)...) {}
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template <class _Up, class... _Args>
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requires is_constructible_v<_Err, initializer_list<_Up>&, _Args...>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(in_place_t, initializer_list<_Up> __il, _Args&&... __args) //
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noexcept(is_nothrow_constructible_v<_Err, initializer_list<_Up>&, _Args...>) // strengthened
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: __unex_(__il, std::forward<_Args>(__args)...) {}
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_LIBCPP_HIDE_FROM_ABI constexpr unexpected& operator=(const unexpected&) = default;
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_LIBCPP_HIDE_FROM_ABI constexpr unexpected& operator=(unexpected&&) = default;
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_LIBCPP_HIDE_FROM_ABI constexpr const _Err& error() const& noexcept { return __unex_; }
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_LIBCPP_HIDE_FROM_ABI constexpr _Err& error() & noexcept { return __unex_; }
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_LIBCPP_HIDE_FROM_ABI constexpr const _Err&& error() const&& noexcept { return std::move(__unex_); }
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_LIBCPP_HIDE_FROM_ABI constexpr _Err&& error() && noexcept { return std::move(__unex_); }
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_LIBCPP_HIDE_FROM_ABI constexpr void swap(unexpected& __other) noexcept(is_nothrow_swappable_v<_Err>) {
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static_assert(is_swappable_v<_Err>, "unexpected::swap requires is_swappable_v<E> to be true");
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using std::swap;
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swap(__unex_, __other.__unex_);
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}
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_LIBCPP_HIDE_FROM_ABI friend constexpr void swap(unexpected& __x, unexpected& __y) noexcept(noexcept(__x.swap(__y)))
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requires is_swappable_v<_Err>
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{
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__x.swap(__y);
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}
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template <class _Err2>
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_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const unexpected& __x, const unexpected<_Err2>& __y) {
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return __x.__unex_ == __y.__unex_;
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}
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private:
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_Err __unex_;
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};
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template <class _Err>
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unexpected(_Err) -> unexpected<_Err>;
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 23
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___EXPECTED_UNEXPECTED_H
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