1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___TUPLE_SFINAE_HELPERS_H 10 #define _LIBCPP___TUPLE_SFINAE_HELPERS_H 11 12 #include <__config> 13 #include <__fwd/tuple.h> 14 #include <__tuple/make_tuple_types.h> 15 #include <__tuple/tuple_element.h> 16 #include <__tuple/tuple_like_ext.h> 17 #include <__tuple/tuple_size.h> 18 #include <__tuple/tuple_types.h> 19 #include <__type_traits/enable_if.h> 20 #include <__type_traits/integral_constant.h> 21 #include <__type_traits/is_assignable.h> 22 #include <__type_traits/is_constructible.h> 23 #include <__type_traits/is_convertible.h> 24 #include <__type_traits/is_same.h> 25 #include <__type_traits/remove_cvref.h> 26 #include <__type_traits/remove_reference.h> 27 #include <cstddef> 28 29 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 30 # pragma GCC system_header 31 #endif 32 33 _LIBCPP_BEGIN_NAMESPACE_STD 34 35 #ifndef _LIBCPP_CXX03_LANG 36 37 template <bool ..._Preds> 38 struct __all_dummy; 39 40 template <bool ..._Pred> 41 struct __all : _IsSame<__all_dummy<_Pred...>, __all_dummy<((void)_Pred, true)...>> {}; 42 43 struct __tuple_sfinae_base { 44 template <template <class, class...> class _Trait, 45 class ..._LArgs, class ..._RArgs> 46 static auto __do_test(__tuple_types<_LArgs...>, __tuple_types<_RArgs...>) 47 -> __all<__enable_if_t<_Trait<_LArgs, _RArgs>::value, bool>{true}...>; 48 template <template <class...> class> 49 static auto __do_test(...) -> false_type; 50 51 template <class _FromArgs, class _ToArgs> 52 using __constructible = decltype(__do_test<is_constructible>(_ToArgs{}, _FromArgs{})); 53 template <class _FromArgs, class _ToArgs> 54 using __convertible = decltype(__do_test<is_convertible>(_FromArgs{}, _ToArgs{})); 55 template <class _FromArgs, class _ToArgs> 56 using __assignable = decltype(__do_test<is_assignable>(_ToArgs{}, _FromArgs{})); 57 }; 58 59 // __tuple_convertible 60 61 template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value, 62 bool = __tuple_like_ext<_Up>::value> 63 struct __tuple_convertible 64 : public false_type {}; 65 66 template <class _Tp, class _Up> 67 struct __tuple_convertible<_Tp, _Up, true, true> 68 : public __tuple_sfinae_base::__convertible< 69 typename __make_tuple_types<_Tp>::type 70 , typename __make_tuple_types<_Up>::type 71 > 72 {}; 73 74 // __tuple_constructible 75 76 template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value, 77 bool = __tuple_like_ext<_Up>::value> 78 struct __tuple_constructible 79 : public false_type {}; 80 81 template <class _Tp, class _Up> 82 struct __tuple_constructible<_Tp, _Up, true, true> 83 : public __tuple_sfinae_base::__constructible< 84 typename __make_tuple_types<_Tp>::type 85 , typename __make_tuple_types<_Up>::type 86 > 87 {}; 88 89 // __tuple_assignable 90 91 template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value, 92 bool = __tuple_like_ext<_Up>::value> 93 struct __tuple_assignable 94 : public false_type {}; 95 96 template <class _Tp, class _Up> 97 struct __tuple_assignable<_Tp, _Up, true, true> 98 : public __tuple_sfinae_base::__assignable< 99 typename __make_tuple_types<_Tp>::type 100 , typename __make_tuple_types<_Up&>::type 101 > 102 {}; 103 104 105 template <size_t _Ip, class ..._Tp> 106 struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, tuple<_Tp...> > 107 { 108 typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type; 109 }; 110 111 struct _LIBCPP_EXPORTED_FROM_ABI __check_tuple_constructor_fail { 112 113 static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_explicit_default() { return false; } 114 static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_implicit_default() { return false; } 115 template <class ...> 116 static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_explicit() { return false; } 117 template <class ...> 118 static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_implicit() { return false; } 119 template <class ...> 120 static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_assign() { return false; } 121 }; 122 #endif // !defined(_LIBCPP_CXX03_LANG) 123 124 #if _LIBCPP_STD_VER >= 17 125 126 template <bool _CanCopy, bool _CanMove> 127 struct __sfinae_ctor_base {}; 128 template <> 129 struct __sfinae_ctor_base<false, false> { 130 __sfinae_ctor_base() = default; 131 __sfinae_ctor_base(__sfinae_ctor_base const&) = delete; 132 __sfinae_ctor_base(__sfinae_ctor_base &&) = delete; 133 __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default; 134 __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default; 135 }; 136 template <> 137 struct __sfinae_ctor_base<true, false> { 138 __sfinae_ctor_base() = default; 139 __sfinae_ctor_base(__sfinae_ctor_base const&) = default; 140 __sfinae_ctor_base(__sfinae_ctor_base &&) = delete; 141 __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default; 142 __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default; 143 }; 144 template <> 145 struct __sfinae_ctor_base<false, true> { 146 __sfinae_ctor_base() = default; 147 __sfinae_ctor_base(__sfinae_ctor_base const&) = delete; 148 __sfinae_ctor_base(__sfinae_ctor_base &&) = default; 149 __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default; 150 __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default; 151 }; 152 153 template <bool _CanCopy, bool _CanMove> 154 struct __sfinae_assign_base {}; 155 template <> 156 struct __sfinae_assign_base<false, false> { 157 __sfinae_assign_base() = default; 158 __sfinae_assign_base(__sfinae_assign_base const&) = default; 159 __sfinae_assign_base(__sfinae_assign_base &&) = default; 160 __sfinae_assign_base& operator=(__sfinae_assign_base const&) = delete; 161 __sfinae_assign_base& operator=(__sfinae_assign_base&&) = delete; 162 }; 163 template <> 164 struct __sfinae_assign_base<true, false> { 165 __sfinae_assign_base() = default; 166 __sfinae_assign_base(__sfinae_assign_base const&) = default; 167 __sfinae_assign_base(__sfinae_assign_base &&) = default; 168 __sfinae_assign_base& operator=(__sfinae_assign_base const&) = default; 169 __sfinae_assign_base& operator=(__sfinae_assign_base&&) = delete; 170 }; 171 template <> 172 struct __sfinae_assign_base<false, true> { 173 __sfinae_assign_base() = default; 174 __sfinae_assign_base(__sfinae_assign_base const&) = default; 175 __sfinae_assign_base(__sfinae_assign_base &&) = default; 176 __sfinae_assign_base& operator=(__sfinae_assign_base const&) = delete; 177 __sfinae_assign_base& operator=(__sfinae_assign_base&&) = default; 178 }; 179 #endif // _LIBCPP_STD_VER >= 17 180 181 _LIBCPP_END_NAMESPACE_STD 182 183 #endif // _LIBCPP___TUPLE_SFINAE_HELPERS_H 184