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/tuple_like_no_subrange.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 _Tp, class = void>
  44 struct __uses_allocator_construction_args;
  45
  46 namespace __uses_allocator_detail {
  47
  48 template <class _Ap, class _Bp>
  49 void __fun(const pair<_Ap, _Bp>&);
  50
  51 template <class _Tp>
  52 decltype(__uses_allocator_detail::__fun(std::declval<_Tp>()), true_type()) __convertible_to_const_pair_ref_impl(int);
  53
  54 template <class>
  55 false_type __convertible_to_const_pair_ref_impl(...);
  56
  57 template <class _Tp>
  58 inline constexpr bool __convertible_to_const_pair_ref =
  59     decltype(__uses_allocator_detail::__convertible_to_const_pair_ref_impl<_Tp>(0))::value;
  60
  61 #  if _LIBCPP_STD_VER >= 23
  62 template <class _Tp, class _Up>
  63 inline constexpr bool __uses_allocator_constraints =
  64     __is_cv_std_pair<_Tp> && !__pair_like_no_subrange<_Up> && !__convertible_to_const_pair_ref<_Up>;
  65 #  else
  66 template <class _Tp, class _Up>
  67 inline constexpr bool __uses_allocator_constraints = __is_cv_std_pair<_Tp> && !__convertible_to_const_pair_ref<_Up>;
  68 #  endif
  69
  70 } // namespace __uses_allocator_detail
  71
  72 template <class _Type, class _Alloc, class... _Args>
  73 _LIBCPP_HIDE_FROM_ABI constexpr _Type __make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args);
  74
  75 template <class _Pair>
  76 struct __uses_allocator_construction_args<_Pair, __enable_if_t<__is_cv_std_pair<_Pair>>> {
  77   template <class _Alloc, class _Tuple1, class _Tuple2>
  78   static _LIBCPP_HIDE_FROM_ABI constexpr auto
  79   __apply(const _Alloc& __alloc, piecewise_construct_t, _Tuple1&& __x, _Tuple2&& __y) noexcept {
  80     return std::make_tuple(
  81         piecewise_construct,
  82         std::apply(
  83             [&__alloc](auto&&... __args1) {
  84               return __uses_allocator_construction_args<typename _Pair::first_type>::__apply(
  85                   __alloc, std::forward<decltype(__args1)>(__args1)...);
  86             },
  87             std::forward<_Tuple1>(__x)),
  88         std::apply(
  89             [&__alloc](auto&&... __args2) {
  90               return __uses_allocator_construction_args<typename _Pair::second_type>::__apply(
  91                   __alloc, std::forward<decltype(__args2)>(__args2)...);
  92             },
  93             std::forward<_Tuple2>(__y)));
  94   }
  95
  96   template <class _Alloc>
  97   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc) noexcept {
  98     return __uses_allocator_construction_args<_Pair>::__apply(__alloc, piecewise_construct, tuple<>{}, tuple<>{});
  99   }
 100
 101   template <class _Alloc, class _Up, class _Vp>
 102   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _Up&& __u, _Vp&& __v) noexcept {
 103     return __uses_allocator_construction_args<_Pair>::__apply(
 104         __alloc,
 105         piecewise_construct,
 106         std::forward_as_tuple(std::forward<_Up>(__u)),
 107         std::forward_as_tuple(std::forward<_Vp>(__v)));
 108   }
 109
 110 #  if _LIBCPP_STD_VER >= 23
 111   template <class _Alloc, class _Up, class _Vp>
 112   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, 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 #  endif
 117
 118   template <class _Alloc, class _Up, class _Vp>
 119   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, const pair<_Up, _Vp>& __pair) noexcept {
 120     return __uses_allocator_construction_args<_Pair>::__apply(
 121         __alloc, piecewise_construct, std::forward_as_tuple(__pair.first), std::forward_as_tuple(__pair.second));
 122   }
 123
 124   template <class _Alloc, class _Up, class _Vp>
 125   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, pair<_Up, _Vp>&& __pair) noexcept {
 126     return __uses_allocator_construction_args<_Pair>::__apply(
 127         __alloc,
 128         piecewise_construct,
 129         std::forward_as_tuple(std::get<0>(std::move(__pair))),
 130         std::forward_as_tuple(std::get<1>(std::move(__pair))));
 131   }
 132
 133 #  if _LIBCPP_STD_VER >= 23
 134   template <class _Alloc, class _Up, class _Vp>
 135   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, const pair<_Up, _Vp>&& __pair) noexcept {
 136     return __uses_allocator_construction_args<_Pair>::__apply(
 137         __alloc,
 138         piecewise_construct,
 139         std::forward_as_tuple(std::get<0>(std::move(__pair))),
 140         std::forward_as_tuple(std::get<1>(std::move(__pair))));
 141   }
 142
 143   template < class _Alloc, __pair_like_no_subrange _PairLike>
 144   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _PairLike&& __p) noexcept {
 145     return __uses_allocator_construction_args<_Pair>::__apply(
 146         __alloc,
 147         piecewise_construct,
 148         std::forward_as_tuple(std::get<0>(std::forward<_PairLike>(__p))),
 149         std::forward_as_tuple(std::get<1>(std::forward<_PairLike>(__p))));
 150   }
 151 #  endif
 152
 153   template <class _Alloc,
 154             class _Type,
 155             __enable_if_t<__uses_allocator_detail::__uses_allocator_constraints<_Pair, _Type>, int> = 0>
 156   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _Type&& __value) noexcept {
 157     struct __pair_constructor {
 158       using _PairMutable = remove_cv_t<_Pair>;
 159
 160       _LIBCPP_HIDDEN constexpr auto __do_construct(const _PairMutable& __pair) const {
 161         return std::__make_obj_using_allocator<_PairMutable>(__alloc_, __pair);
 162       }
 163
 164       _LIBCPP_HIDDEN constexpr auto __do_construct(_PairMutable&& __pair) const {
 165         return std::__make_obj_using_allocator<_PairMutable>(__alloc_, std::move(__pair));
 166       }
 167
 168       const _Alloc& __alloc_;
 169       _Type& __value_;
 170
 171       _LIBCPP_HIDDEN constexpr operator _PairMutable() const { return __do_construct(std::forward<_Type>(__value_)); }
 172     };
 173
 174     return std::make_tuple(__pair_constructor{__alloc, __value});
 175   }
 176 };
 177
 178 template <class _Type>
 179 struct __uses_allocator_construction_args<_Type, __enable_if_t<!__is_cv_std_pair<_Type>>> {
 180   template <class _Alloc, class... _Args>
 181   static _LIBCPP_HIDE_FROM_ABI constexpr auto __apply(const _Alloc& __alloc, _Args&&... __args) noexcept {
 182     if constexpr (!uses_allocator_v<remove_cv_t<_Type>, _Alloc> && is_constructible_v<_Type, _Args...>) {
 183       return std::forward_as_tuple(std::forward<_Args>(__args)...);
 184     } else if constexpr (uses_allocator_v<remove_cv_t<_Type>, _Alloc> &&
 185                          is_constructible_v<_Type, allocator_arg_t, const _Alloc&, _Args...>) {
 186       return tuple<allocator_arg_t, const _Alloc&, _Args&&...>(allocator_arg, __alloc, std::forward<_Args>(__args)...);
 187     } else if constexpr (uses_allocator_v<remove_cv_t<_Type>, _Alloc> &&
 188                          is_constructible_v<_Type, _Args..., const _Alloc&>) {
 189       return std::forward_as_tuple(std::forward<_Args>(__args)..., __alloc);
 190     } else {
 191       static_assert(
 192           sizeof(_Type) + 1 == 0, "If uses_allocator_v<Type> is true, the type has to be allocator-constructible");
 193     }
 194   }
 195 };
 196
 197 template <class _Type, class _Alloc, class... _Args>
 198 _LIBCPP_HIDE_FROM_ABI constexpr _Type __make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args) {
 199   return std::make_from_tuple<_Type>(
 200       __uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...));
 201 }
 202
 203 template <class _Type, class _Alloc, class... _Args>
 204 _LIBCPP_HIDE_FROM_ABI constexpr _Type*
 205 __uninitialized_construct_using_allocator(_Type* __ptr, const _Alloc& __alloc, _Args&&... __args) {
 206   return std::apply(
 207       [&__ptr](auto&&... __xs) { return std::__construct_at(__ptr, std::forward<decltype(__xs)>(__xs)...); },
 208       __uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...));
 209 }
 210
 211 #endif // _LIBCPP_STD_VER >= 17
 212
 213 #if _LIBCPP_STD_VER >= 20
 214
 215 template <class _Type, class _Alloc, class... _Args>
 216 _LIBCPP_HIDE_FROM_ABI constexpr auto uses_allocator_construction_args(const _Alloc& __alloc, _Args&&... __args) noexcept
 217     -> decltype(__uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...)) {
 218   return /*--*/ __uses_allocator_construction_args<_Type>::__apply(__alloc, std::forward<_Args>(__args)...);
 219 }
 220
 221 template <class _Type, class _Alloc, class... _Args>
 222 _LIBCPP_HIDE_FROM_ABI constexpr auto make_obj_using_allocator(const _Alloc& __alloc, _Args&&... __args)
 223     -> decltype(std::__make_obj_using_allocator<_Type>(__alloc, std::forward<_Args>(__args)...)) {
 224   return /*--*/ std::__make_obj_using_allocator<_Type>(__alloc, std::forward<_Args>(__args)...);
 225 }
 226
 227 template <class _Type, class _Alloc, class... _Args>
 228 _LIBCPP_HIDE_FROM_ABI constexpr auto
 229 uninitialized_construct_using_allocator(_Type* __ptr, const _Alloc& __alloc, _Args&&... __args)
 230     -> decltype(std::__uninitialized_construct_using_allocator(__ptr, __alloc, std::forward<_Args>(__args)...)) {
 231   return /*--*/ std::__uninitialized_construct_using_allocator(__ptr, __alloc, std::forward<_Args>(__args)...);
 232 }
 233
 234 #endif // _LIBCPP_STD_VER >= 20
 235
 236 _LIBCPP_END_NAMESPACE_STD
 237
 238 _LIBCPP_POP_MACROS
 239
 240 #endif // _LIBCPP___MEMORY_USES_ALLOCATOR_CONSTRUCTION_H