libcxx/include/__memory/uses_allocator_construction.h

   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/pair_like.h>
  16 #include <__type_traits/enable_if.h>
  17 #include <__type_traits/is_same.h>
  18 #include <__type_traits/remove_cv.h>
  19 #include <__utility/declval.h>
  20 #include <__utility/pair.h>
  21 #include <tuple>
  22
  23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  24 #  pragma GCC system_header
  25 #endif
  26
  27 _LIBCPP_PUSH_MACROS
  28 #include <__undef_macros>
  29
  30 _LIBCPP_BEGIN_NAMESPACE_STD
  31
  32 #if _LIBCPP_STD_VER >= 17
  33
  34 template <class _Type>
  35 inline constexpr bool __is_std_pair = false;
  36
  37 template <class _Type1, class _Type2>
  38 inline constexpr bool __is_std_pair<pair<_Type1, _Type2>> = true;
  39
  40 template <class _Tp>
  41 inline constexpr bool __is_cv_std_pair = __is_std_pair<remove_cv_t<_Tp>>;
  42
  43 template <class _Type, class _Alloc, class... _Args, __enable_if_t<!__is_cv_std_pair<_Type>, int> = 0>
  44 _LIBCPP_HIDE_FROM_ABI constexpr auto
  45 __uses_allocator_construction_args(const _Alloc& __alloc, _Args&&... __args) noexcept {
  46   if constexpr (!uses_allocator_v<remove_cv_t<_Type>, _Alloc> && is_constructible_v<_Type, _Args...>) {
  47     return std::forward_as_tuple(std::forward<_Args>(__args)...);
  48   } else if constexpr (uses_allocator_v<remove_cv_t<_Type>, _Alloc> &&
  49                        is_constructible_v<_Type, allocator_arg_t, const _Alloc&, _Args...>) {
  50     return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(allocator_arg, __alloc, std::forward<_Args>(__args)...);
  51   } else if constexpr (uses_allocator_v<remove_cv_t<_Type>, _Alloc> &&
  52                        is_constructible_v<_Type, _Args..., const _Alloc&>) {
  53     return std::forward_as_tuple(std::forward<_Args>(__args)..., __alloc);
  54   } else {
  55     static_assert(
  56         sizeof(_Type) + 1 == 0, "If uses_allocator_v<Type> is true, the type has to be allocator-constructible");
  57   }
  58 }
  59
  60 template <class _Pair, class _Alloc, class _Tuple1, class _Tuple2, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
  61 _LIBCPP_HIDE_FROM_ABI constexpr auto __uses_allocator_construction_args(
  62     const _Alloc& __alloc, piecewise_construct_t, _Tuple1&& __x, _Tuple2&& __y) noexcept {
  63   return std::make_tuple(
  64       piecewise_construct,
  65       std::apply(
  66           [&__alloc](auto&&... __args1) {
  67             return std::__uses_allocator_construction_args<typename _Pair::first_type>(
  68                 __alloc, std::forward<decltype(__args1)>(__args1)...);
  69           },
  70           std::forward<_Tuple1>(__x)),
  71       std::apply(
  72           [&__alloc](auto&&... __args2) {
  73             return std::__uses_allocator_construction_args<typename _Pair::second_type>(
  74                 __alloc, std::forward<decltype(__args2)>(__args2)...);
  75           },
  76           std::forward<_Tuple2>(__y)));
  77 }
  78
  79 template <class _Pair, class _Alloc, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
  80 _LIBCPP_HIDE_FROM_ABI constexpr auto __uses_allocator_construction_args(const _Alloc& __alloc) noexcept {
  81   return std::__uses_allocator_construction_args<_Pair>(__alloc, piecewise_construct, tuple<>{}, tuple<>{});
  82 }
  83
  84 template <class _Pair, class _Alloc, class _Up, class _Vp, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
  85 _LIBCPP_HIDE_FROM_ABI constexpr auto
  86 __uses_allocator_construction_args(const _Alloc& __alloc, _Up&& __u, _Vp&& __v) noexcept {
  87   return std::__uses_allocator_construction_args<_Pair>(
  88       __alloc,
  89       piecewise_construct,
  90       std::forward_as_tuple(std::forward<_Up>(__u)),
  91       std::forward_as_tuple(std::forward<_Vp>(__v)));
  92 }
  93
  94 #  if _LIBCPP_STD_VER >= 23
  95 template <class _Pair, class _Alloc, class _Up, class _Vp, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
  96 _LIBCPP_HIDE_FROM_ABI constexpr auto
  97 __uses_allocator_construction_args(const _Alloc& __alloc, pair<_Up, _Vp>& __pair) noexcept {
  98   return std::__uses_allocator_construction_args<_Pair>(
  99       __alloc, piecewise_construct, std::forward_as_tuple(__pair.first), std::forward_as_tuple(__pair.second));
 100 }
 101 #  endif
 102
 103 template <class _Pair, class _Alloc, class _Up, class _Vp, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
 104 _LIBCPP_HIDE_FROM_ABI constexpr auto
 105 __uses_allocator_construction_args(const _Alloc& __alloc, const pair<_Up, _Vp>& __pair) noexcept {
 106   return std::__uses_allocator_construction_args<_Pair>(
 107       __alloc, piecewise_construct, std::forward_as_tuple(__pair.first), std::forward_as_tuple(__pair.second));
 108 }
 109
 110 template <class _Pair, class _Alloc, class _Up, class _Vp, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
 111 _LIBCPP_HIDE_FROM_ABI constexpr auto
 112 __uses_allocator_construction_args(const _Alloc& __alloc, pair<_Up, _Vp>&& __pair) noexcept {
 113   return std::__uses_allocator_construction_args<_Pair>(
 114       __alloc,
 115       piecewise_construct,
 116       std::forward_as_tuple(std::get<0>(std::move(__pair))),
 117       std::forward_as_tuple(std::get<1>(std::move(__pair))));
 118 }
 119
 120 #  if _LIBCPP_STD_VER >= 23
 121 template <class _Pair, class _Alloc, class _Up, class _Vp, __enable_if_t<__is_cv_std_pair<_Pair>, int> = 0>
 122 _LIBCPP_HIDE_FROM_ABI constexpr auto
 123 __uses_allocator_construction_args(const _Alloc& __alloc, const pair<_Up, _Vp>&& __pair) noexcept {
 124   return std::__uses_allocator_construction_args<_Pair>(
 125       __alloc,
 126       piecewise_construct,
 127       std::forward_as_tuple(std::get<0>(std::move(__pair))),
 128       std::forward_as_tuple(std::get<1>(std::move(__pair))));
 129 }
 130
 131 template < class _Pair,
 132            class _Alloc,
 133            __pair_like _PairLike,
 134            __enable_if_t<__is_cv_std_pair<_Pair> && !__is_specialization_of_subrange<remove_cvref_t<_PairLike>>::value,
 135                          int> = 0>
 136 _LIBCPP_HIDE_FROM_ABI constexpr auto
 137 __uses_allocator_construction_args(const _Alloc& __alloc, _PairLike&& __p) noexcept {
 138   return std::__uses_allocator_construction_args<_Pair>(
 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 namespace __uses_allocator_detail {
 147
 148 template <class _Ap, class _Bp>
 149 void __fun(const pair<_Ap, _Bp>&);
 150
 151 template <class _Tp>
 152 decltype(__uses_allocator_detail::__fun(std::declval<_Tp>()), true_type()) __convertible_to_const_pair_ref_impl(int);
 153
 154 template <class>
 155 false_type __convertible_to_const_pair_ref_impl(...);
 156
 157 template <class _Tp>
 158 inline constexpr bool __convertible_to_const_pair_ref =
 159     decltype(__uses_allocator_detail::__convertible_to_const_pair_ref_impl<_Tp>(0))::value;
 160
 161 #  if _LIBCPP_STD_VER >= 23
 162 template <class _Tp, class _Up>
 163 inline constexpr bool __uses_allocator_constraints =
 164     __is_cv_std_pair<_Tp> &&
 165     (__is_specialization_of_subrange<remove_cvref_t<_Up>>::value ||
 166      (!__pair_like<_Up> && !__convertible_to_const_pair_ref<_Up>));
 167 #  else
 168 template <class _Tp, class _Up>
 169 inline constexpr bool __uses_allocator_constraints = __is_cv_std_pair<_Tp> && !__convertible_to_const_pair_ref<_Up>;
 170 #  endif
 171
 172 } // namespace __uses_allocator_detail
 173
 174 template < class _Pair,
 175            class _Alloc,
 176            class _Type,
 177            __enable_if_t<__uses_allocator_detail::__uses_allocator_constraints<_Pair, _Type>, int> = 0>
 178 _LIBCPP_HIDE_FROM_ABI constexpr auto
 179 __uses_allocator_construction_args(const _Alloc& __alloc, _Type&& __value) noexcept;
 180
 181 template <class _Type, class _Alloc, class... _Args>
 182 _LIBCPP_HIDE_FROM_ABI constexpr _Type __make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args);
 183
 184 template < class _Pair,
 185            class _Alloc,
 186            class _Type,
 187            __enable_if_t< __uses_allocator_detail::__uses_allocator_constraints<_Pair, _Type>, int>>
 188 _LIBCPP_HIDE_FROM_ABI constexpr auto
 189 __uses_allocator_construction_args(const _Alloc& __alloc, _Type&& __value) noexcept {
 190   struct __pair_constructor {
 191     using _PairMutable = remove_cv_t<_Pair>;
 192
 193     _LIBCPP_HIDE_FROM_ABI constexpr auto __do_construct(const _PairMutable& __pair) const {
 194       return std::__make_obj_using_allocator<_PairMutable>(__alloc_, __pair);
 195     }
 196
 197     _LIBCPP_HIDE_FROM_ABI constexpr auto __do_construct(_PairMutable&& __pair) const {
 198       return std::__make_obj_using_allocator<_PairMutable>(__alloc_, std::move(__pair));
 199     }
 200
 201     const _Alloc& __alloc_;
 202     _Type& __value_;
 203
 204     _LIBCPP_HIDE_FROM_ABI constexpr operator _PairMutable() const {
 205       return __do_construct(std::forward<_Type>(this->__value_));
 206     }
 207   };
 208
 209   return std::make_tuple(__pair_constructor{__alloc, __value});
 210 }
 211
 212 template <class _Type, class _Alloc, class... _Args>
 213 _LIBCPP_HIDE_FROM_ABI constexpr _Type __make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args) {
 214   return std::make_from_tuple<_Type>(
 215       std::__uses_allocator_construction_args<_Type>(__alloc, std::forward<_Args>(__args)...));
 216 }
 217
 218 template <class _Type, class _Alloc, class... _Args>
 219 _LIBCPP_HIDE_FROM_ABI constexpr _Type*
 220 __uninitialized_construct_using_allocator(_Type* __ptr, const _Alloc& __alloc, _Args&&... __args) {
 221   return std::apply(
 222       [&__ptr](auto&&... __xs) { return std::__construct_at(__ptr, std::forward<decltype(__xs)>(__xs)...); },
 223       std::__uses_allocator_construction_args<_Type>(__alloc, std::forward<_Args>(__args)...));
 224 }
 225
 226 #endif // _LIBCPP_STD_VER >= 17
 227
 228 #if _LIBCPP_STD_VER >= 20
 229
 230 template <class _Type, class _Alloc, class... _Args>
 231 _LIBCPP_HIDE_FROM_ABI constexpr auto uses_allocator_construction_args(const _Alloc& __alloc, _Args&&... __args) noexcept
 232     -> decltype(std::__uses_allocator_construction_args<_Type>(__alloc, std::forward<_Args>(__args)...)) {
 233   return /*--*/ std::__uses_allocator_construction_args<_Type>(__alloc, std::forward<_Args>(__args)...);
 234 }
 235
 236 template <class _Type, class _Alloc, class... _Args>
 237 _LIBCPP_HIDE_FROM_ABI constexpr auto make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args)
 238     -> decltype(std::__make_obj_using_allocator<_Type>(__alloc, std::forward<_Args>(__args)...)) {
 239   return /*--*/ std::__make_obj_using_allocator<_Type>(__alloc, std::forward<_Args>(__args)...);
 240 }
 241
 242 template <class _Type, class _Alloc, class... _Args>
 243 _LIBCPP_HIDE_FROM_ABI constexpr auto
 244 uninitialized_construct_using_allocator(_Type* __ptr, const _Alloc& __alloc, _Args&&... __args)
 245     -> decltype(std::__uninitialized_construct_using_allocator(__ptr, __alloc, std::forward<_Args>(__args)...)) {
 246   return /*--*/ std::__uninitialized_construct_using_allocator(__ptr, __alloc, std::forward<_Args>(__args)...);
 247 }
 248
 249 #endif // _LIBCPP_STD_VER >= 20
 250
 251 _LIBCPP_END_NAMESPACE_STD
 252
 253 _LIBCPP_POP_MACROS
 254
 255 #endif // _LIBCPP___MEMORY_USES_ALLOCATOR_CONSTRUCTION_H