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Diffstat (limited to 'libcxx/include/__expected/unexpected.h')
| -rw-r--r-- | libcxx/include/__expected/unexpected.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/libcxx/include/__expected/unexpected.h b/libcxx/include/__expected/unexpected.h new file mode 100644 index 000000000000..075963a84ded --- /dev/null +++ b/libcxx/include/__expected/unexpected.h @@ -0,0 +1,122 @@ +// -*- C++ -*- +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +#ifndef _LIBCPP___EXPECTED_UNEXPECTED_H +#define _LIBCPP___EXPECTED_UNEXPECTED_H + +#include <__config> +#include <__type_traits/conjunction.h> +#include <__type_traits/is_array.h> +#include <__type_traits/is_const.h> +#include <__type_traits/is_constructible.h> +#include <__type_traits/is_nothrow_constructible.h> +#include <__type_traits/is_object.h> +#include <__type_traits/is_same.h> +#include <__type_traits/is_swappable.h> +#include <__type_traits/is_volatile.h> +#include <__type_traits/negation.h> +#include <__type_traits/remove_cvref.h> +#include <__utility/forward.h> +#include <__utility/in_place.h> +#include <__utility/move.h> +#include <__utility/swap.h> +#include <initializer_list> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +#endif + +#if _LIBCPP_STD_VER >= 23 + +_LIBCPP_BEGIN_NAMESPACE_STD + +template <class _Err> +class unexpected; + +template <class _Tp> +struct __is_std_unexpected : false_type {}; + +template <class _Err> +struct __is_std_unexpected<unexpected<_Err>> : true_type {}; + +template <class _Tp> +using __valid_std_unexpected = _BoolConstant< // + is_object_v<_Tp> && // + !is_array_v<_Tp> && // + !__is_std_unexpected<_Tp>::value && // + !is_const_v<_Tp> && // + !is_volatile_v<_Tp> // + >; + +template <class _Err> +class unexpected { + static_assert(__valid_std_unexpected<_Err>::value, + "[expected.un.general] states a program that instantiates std::unexpected for a non-object type, an " + "array type, a specialization of unexpected, or a cv-qualified type is ill-formed."); + +public: + _LIBCPP_HIDE_FROM_ABI constexpr unexpected(const unexpected&) = default; + _LIBCPP_HIDE_FROM_ABI constexpr unexpected(unexpected&&) = default; + + template <class _Error = _Err> + requires(!is_same_v<remove_cvref_t<_Error>, unexpected> && // + !is_same_v<remove_cvref_t<_Error>, in_place_t> && // + is_constructible_v<_Err, _Error>) + _LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(_Error&& __error) // + noexcept(is_nothrow_constructible_v<_Err, _Error>) // strengthened + : __unex_(std::forward<_Error>(__error)) {} + + template <class... _Args> + requires is_constructible_v<_Err, _Args...> + _LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(in_place_t, _Args&&... __args) // + noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened + : __unex_(std::forward<_Args>(__args)...) {} + + template <class _Up, class... _Args> + requires is_constructible_v<_Err, initializer_list<_Up>&, _Args...> + _LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(in_place_t, initializer_list<_Up> __il, _Args&&... __args) // + noexcept(is_nothrow_constructible_v<_Err, initializer_list<_Up>&, _Args...>) // strengthened + : __unex_(__il, std::forward<_Args>(__args)...) {} + + _LIBCPP_HIDE_FROM_ABI constexpr unexpected& operator=(const unexpected&) = default; + _LIBCPP_HIDE_FROM_ABI constexpr unexpected& operator=(unexpected&&) = default; + + _LIBCPP_HIDE_FROM_ABI constexpr const _Err& error() const& noexcept { return __unex_; } + _LIBCPP_HIDE_FROM_ABI constexpr _Err& error() & noexcept { return __unex_; } + _LIBCPP_HIDE_FROM_ABI constexpr const _Err&& error() const&& noexcept { return std::move(__unex_); } + _LIBCPP_HIDE_FROM_ABI constexpr _Err&& error() && noexcept { return std::move(__unex_); } + + _LIBCPP_HIDE_FROM_ABI constexpr void swap(unexpected& __other) noexcept(is_nothrow_swappable_v<_Err>) { + static_assert(is_swappable_v<_Err>, "unexpected::swap requires is_swappable_v<E> to be true"); + using std::swap; + swap(__unex_, __other.__unex_); + } + + _LIBCPP_HIDE_FROM_ABI friend constexpr void swap(unexpected& __x, unexpected& __y) noexcept(noexcept(__x.swap(__y))) + requires is_swappable_v<_Err> + { + __x.swap(__y); + } + + template <class _Err2> + _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const unexpected& __x, const unexpected<_Err2>& __y) { + return __x.__unex_ == __y.__unex_; + } + +private: + _Err __unex_; +}; + +template <class _Err> +unexpected(_Err) -> unexpected<_Err>; + +_LIBCPP_END_NAMESPACE_STD + +#endif // _LIBCPP_STD_VER >= 23 + +#endif // _LIBCPP___EXPECTED_UNEXPECTED_H |