xref: /freebsd/contrib/llvm-project/libcxx/include/__memory/uses_allocator_construction.h (revision 700637cbb5e582861067a11aaca4d053546871d2)
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___MEMORY_USES_ALLOCATOR_CONSTRUCTION_H
10 #define _LIBCPP___MEMORY_USES_ALLOCATOR_CONSTRUCTION_H
11 
12 #include <__config>
13 #include <__memory/construct_at.h>
14 #include <__memory/uses_allocator.h>
15 #include <__tuple/tuple_like_no_subrange.h>
16 #include <__type_traits/enable_if.h>
17 #include <__type_traits/remove_cv.h>
18 #include <__utility/declval.h>
19 #include <__utility/pair.h>
20 #include <tuple>
21 
22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23 #  pragma GCC system_header
24 #endif
25 
26 _LIBCPP_PUSH_MACROS
27 #include <__undef_macros>
28 
29 _LIBCPP_BEGIN_NAMESPACE_STD
30 
31 #if _LIBCPP_STD_VER >= 17
32 
33 template <class _Tp>
34 inline constexpr bool __is_cv_std_pair = __is_pair_v<remove_cv_t<_Tp>>;
35 
36 template <class _Tp, class = void>
37 struct __uses_allocator_construction_args;
38 
39 namespace __uses_allocator_detail {
40 
41 template <class _Ap, class _Bp>
42 void __fun(const pair<_Ap, _Bp>&);
43 
44 template <class _Tp>
45 decltype(__uses_allocator_detail::__fun(std::declval<_Tp>()), true_type()) __convertible_to_const_pair_ref_impl(int);
46 
47 template <class>
48 false_type __convertible_to_const_pair_ref_impl(...);
49 
50 template <class _Tp>
51 inline constexpr bool __convertible_to_const_pair_ref =
52     decltype(__uses_allocator_detail::__convertible_to_const_pair_ref_impl<_Tp>(0))::value;
53 
54 #  if _LIBCPP_STD_VER >= 23
55 template <class _Tp, class _Up>
56 inline constexpr bool __uses_allocator_constraints =
57     __is_cv_std_pair<_Tp> && !__pair_like_no_subrange<_Up> && !__convertible_to_const_pair_ref<_Up>;
58 #  else
59 template <class _Tp, class _Up>
60 inline constexpr bool __uses_allocator_constraints = __is_cv_std_pair<_Tp> && !__convertible_to_const_pair_ref<_Up>;
61 #  endif
62 
63 } // namespace __uses_allocator_detail
64 
65 template <class _Type, class _Alloc, class... _Args>
66 _LIBCPP_HIDE_FROM_ABI constexpr _Type __make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args);
67 
68 template <class _Pair>
69 struct __uses_allocator_construction_args<_Pair, __enable_if_t<__is_cv_std_pair<_Pair>>> {
70   template <class _Alloc, class _Tuple1, class _Tuple2>
71   static _LIBCPP_HIDE_FROM_ABI constexpr auto
72   __apply(const _Alloc& __alloc, piecewise_construct_t, _Tuple1&& __x, _Tuple2&& __y) noexcept {
73     return std::make_tuple(
74         piecewise_construct,
75         std::apply(
76             [&__alloc](auto&&... __args1) {
77               return __uses_allocator_construction_args<typename _Pair::first_type>::__apply(
78                   __alloc, std::forward<decltype(__args1)>(__args1)...);
79             },
80             std::forward<_Tuple1>(__x)),
81         std::apply(
82             [&__alloc](auto&&... __args2) {
83               return __uses_allocator_construction_args<typename _Pair::second_type>::__apply(
84                   __alloc, std::forward<decltype(__args2)>(__args2)...);
85             },
86             std::forward<_Tuple2>(__y)));
87   }
88 
89   template <class _Alloc>
90   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc) noexcept {
91     return __uses_allocator_construction_args<_Pair>::__apply(__alloc, piecewise_construct, tuple<>{}, tuple<>{});
92   }
93 
94   template <class _Alloc, class _Up, class _Vp>
95   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _Up&& __u, _Vp&& __v) noexcept {
96     return __uses_allocator_construction_args<_Pair>::__apply(
97         __alloc,
98         piecewise_construct,
99         std::forward_as_tuple(std::forward<_Up>(__u)),
100         std::forward_as_tuple(std::forward<_Vp>(__v)));
101   }
102 
103 #  if _LIBCPP_STD_VER >= 23
104   template <class _Alloc, class _Up, class _Vp>
105   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, pair<_Up, _Vp>& __pair) noexcept {
106     return __uses_allocator_construction_args<_Pair>::__apply(
107         __alloc, piecewise_construct, std::forward_as_tuple(__pair.first), std::forward_as_tuple(__pair.second));
108   }
109 #  endif
110 
111   template <class _Alloc, class _Up, class _Vp>
112   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, const pair<_Up, _Vp>& __pair) noexcept {
113     return __uses_allocator_construction_args<_Pair>::__apply(
114         __alloc, piecewise_construct, std::forward_as_tuple(__pair.first), std::forward_as_tuple(__pair.second));
115   }
116 
117   template <class _Alloc, class _Up, class _Vp>
118   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, pair<_Up, _Vp>&& __pair) noexcept {
119     return __uses_allocator_construction_args<_Pair>::__apply(
120         __alloc,
121         piecewise_construct,
122         std::forward_as_tuple(std::get<0>(std::move(__pair))),
123         std::forward_as_tuple(std::get<1>(std::move(__pair))));
124   }
125 
126 #  if _LIBCPP_STD_VER >= 23
127   template <class _Alloc, class _Up, class _Vp>
128   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, const pair<_Up, _Vp>&& __pair) noexcept {
129     return __uses_allocator_construction_args<_Pair>::__apply(
130         __alloc,
131         piecewise_construct,
132         std::forward_as_tuple(std::get<0>(std::move(__pair))),
133         std::forward_as_tuple(std::get<1>(std::move(__pair))));
134   }
135 
136   template < class _Alloc, __pair_like_no_subrange _PairLike>
137   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _PairLike&& __p) noexcept {
138     return __uses_allocator_construction_args<_Pair>::__apply(
139         __alloc,
140         piecewise_construct,
141         std::forward_as_tuple(std::get<0>(std::forward<_PairLike>(__p))),
142         std::forward_as_tuple(std::get<1>(std::forward<_PairLike>(__p))));
143   }
144 #  endif
145 
146   template <class _Alloc,
147             class _Type,
148             __enable_if_t<__uses_allocator_detail::__uses_allocator_constraints<_Pair, _Type>, int> = 0>
149   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _Type&& __value) noexcept {
150     struct __pair_constructor {
151       using _PairMutable = remove_cv_t<_Pair>;
152 
153       _LIBCPP_HIDDEN constexpr auto __do_construct(const _PairMutable& __pair) const {
154         return std::__make_obj_using_allocator<_PairMutable>(__alloc_, __pair);
155       }
156 
157       _LIBCPP_HIDDEN constexpr auto __do_construct(_PairMutable&& __pair) const {
158         return std::__make_obj_using_allocator<_PairMutable>(__alloc_, std::move(__pair));
159       }
160 
161       const _Alloc& __alloc_;
162       _Type& __value_;
163 
164       _LIBCPP_HIDDEN constexpr operator _PairMutable() const { return __do_construct(std::forward<_Type>(__value_)); }
165     };
166 
167     return std::make_tuple(__pair_constructor{__alloc, __value});
168   }
169 };
170 
171 template <class _Type>
172 struct __uses_allocator_construction_args<_Type, __enable_if_t<!__is_cv_std_pair<_Type>>> {
173   template <class _Alloc, class... _Args>
174   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _Args&&... __args) noexcept {
175     if constexpr (!uses_allocator_v<remove_cv_t<_Type>, _Alloc> && is_constructible_v<_Type, _Args...>) {
176       return std::forward_as_tuple(std::forward<_Args>(__args)...);
177     } else if constexpr (uses_allocator_v<remove_cv_t<_Type>, _Alloc> &&
178                          is_constructible_v<_Type, allocator_arg_t, const _Alloc&, _Args...>) {
179       return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(allocator_arg, __alloc, std::forward<_Args>(__args)...);
180     } else if constexpr (uses_allocator_v<remove_cv_t<_Type>, _Alloc> &&
181                          is_constructible_v<_Type, _Args..., const _Alloc&>) {
182       return std::forward_as_tuple(std::forward<_Args>(__args)..., __alloc);
183     } else {
184       static_assert(
185           sizeof(_Type) + 1 == 0, "If uses_allocator_v<Type> is true, the type has to be allocator-constructible");
186     }
187   }
188 };
189 
190 template <class _Type, class _Alloc, class... _Args>
191 _LIBCPP_HIDE_FROM_ABI constexpr _Type __make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args) {
192   return std::make_from_tuple<_Type>(
193       __uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...));
194 }
195 
196 template <class _Type, class _Alloc, class... _Args>
197 _LIBCPP_HIDE_FROM_ABI constexpr _Type*
198 __uninitialized_construct_using_allocator(_Type* __ptr, const _Alloc& __alloc, _Args&&... __args) {
199   return std::apply(
200       [&__ptr](auto&&... __xs) { return std::__construct_at(__ptr, std::forward<decltype(__xs)>(__xs)...); },
201       __uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...));
202 }
203 
204 #endif // _LIBCPP_STD_VER >= 17
205 
206 #if _LIBCPP_STD_VER >= 20
207 
208 template <class _Type, class _Alloc, class... _Args>
209 _LIBCPP_HIDE_FROM_ABI constexpr auto uses_allocator_construction_args(const _Alloc& __alloc, _Args&&... __args) noexcept
210     -> decltype(__uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...)) {
211   return /*--*/ __uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...);
212 }
213 
214 template <class _Type, class _Alloc, class... _Args>
215 _LIBCPP_HIDE_FROM_ABI constexpr auto make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args)
216     -> decltype(std::__make_obj_using_allocator<_Type>(__alloc, std::forward<_Args>(__args)...)) {
217   return /*--*/ std::__make_obj_using_allocator<_Type>(__alloc, std::forward<_Args>(__args)...);
218 }
219 
220 template <class _Type, class _Alloc, class... _Args>
221 _LIBCPP_HIDE_FROM_ABI constexpr auto
222 uninitialized_construct_using_allocator(_Type* __ptr, const _Alloc& __alloc, _Args&&... __args)
223     -> decltype(std::__uninitialized_construct_using_allocator(__ptr, __alloc, std::forward<_Args>(__args)...)) {
224   return /*--*/ std::__uninitialized_construct_using_allocator(__ptr, __alloc, std::forward<_Args>(__args)...);
225 }
226 
227 #endif // _LIBCPP_STD_VER >= 20
228 
229 _LIBCPP_END_NAMESPACE_STD
230 
231 _LIBCPP_POP_MACROS
232 
233 #endif // _LIBCPP___MEMORY_USES_ALLOCATOR_CONSTRUCTION_H
234