1 | // Uses-allocator Construction -*- C++ -*- |
2 | |
3 | // Copyright (C) 2010-2021 Free Software Foundation, Inc. |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free |
6 | // software; you can redistribute it and/or modify it under the |
7 | // terms of the GNU General Public License as published by the |
8 | // Free Software Foundation; either version 3, or (at your option) |
9 | // any later version. |
10 | |
11 | // This library is distributed in the hope that it will be useful, |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | // GNU General Public License for more details. |
15 | |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version |
18 | // 3.1, as published by the Free Software Foundation. |
19 | |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
23 | // <http://www.gnu.org/licenses/>. |
24 | |
25 | #ifndef _USES_ALLOCATOR_H |
26 | #define _USES_ALLOCATOR_H 1 |
27 | |
28 | #if __cplusplus < 201103L |
29 | # include <bits/c++0x_warning.h> |
30 | #else |
31 | |
32 | #include <type_traits> |
33 | #include <bits/move.h> |
34 | |
35 | namespace std _GLIBCXX_VISIBILITY(default) |
36 | { |
37 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
38 | /// @cond undocumented |
39 | |
40 | // This is used for std::experimental::erased_type from Library Fundamentals. |
41 | struct __erased_type { }; |
42 | |
43 | // This also supports the "type-erased allocator" protocol from the |
44 | // Library Fundamentals TS, where allocator_type is erased_type. |
45 | // The second condition will always be false for types not using the TS. |
46 | template<typename _Alloc, typename _Tp> |
47 | using __is_erased_or_convertible |
48 | = __or_<is_convertible<_Alloc, _Tp>, is_same<_Tp, __erased_type>>; |
49 | |
50 | /// [allocator.tag] |
51 | struct allocator_arg_t { explicit allocator_arg_t() = default; }; |
52 | |
53 | _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg = |
54 | allocator_arg_t(); |
55 | |
56 | template<typename _Tp, typename _Alloc, typename = __void_t<>> |
57 | struct __uses_allocator_helper |
58 | : false_type { }; |
59 | |
60 | template<typename _Tp, typename _Alloc> |
61 | struct __uses_allocator_helper<_Tp, _Alloc, |
62 | __void_t<typename _Tp::allocator_type>> |
63 | : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type |
64 | { }; |
65 | |
66 | /// [allocator.uses.trait] |
67 | template<typename _Tp, typename _Alloc> |
68 | struct uses_allocator |
69 | : __uses_allocator_helper<_Tp, _Alloc>::type |
70 | { }; |
71 | |
72 | struct __uses_alloc_base { }; |
73 | |
74 | struct __uses_alloc0 : __uses_alloc_base |
75 | { |
76 | struct _Sink { void _GLIBCXX20_CONSTEXPR operator=(const void*) { } } _M_a; |
77 | }; |
78 | |
79 | template<typename _Alloc> |
80 | struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; }; |
81 | |
82 | template<typename _Alloc> |
83 | struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; }; |
84 | |
85 | template<bool, typename _Tp, typename _Alloc, typename... _Args> |
86 | struct __uses_alloc; |
87 | |
88 | template<typename _Tp, typename _Alloc, typename... _Args> |
89 | struct __uses_alloc<true, _Tp, _Alloc, _Args...> |
90 | : conditional< |
91 | is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>::value, |
92 | __uses_alloc1<_Alloc>, |
93 | __uses_alloc2<_Alloc>>::type |
94 | { |
95 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
96 | // 2586. Wrong value category used in scoped_allocator_adaptor::construct |
97 | static_assert(__or_< |
98 | is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>, |
99 | is_constructible<_Tp, _Args..., const _Alloc&>>::value, |
100 | "construction with an allocator must be possible" |
101 | " if uses_allocator is true" ); |
102 | }; |
103 | |
104 | template<typename _Tp, typename _Alloc, typename... _Args> |
105 | struct __uses_alloc<false, _Tp, _Alloc, _Args...> |
106 | : __uses_alloc0 { }; |
107 | |
108 | template<typename _Tp, typename _Alloc, typename... _Args> |
109 | using __uses_alloc_t = |
110 | __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>; |
111 | |
112 | template<typename _Tp, typename _Alloc, typename... _Args> |
113 | _GLIBCXX20_CONSTEXPR |
114 | inline __uses_alloc_t<_Tp, _Alloc, _Args...> |
115 | __use_alloc(const _Alloc& __a) |
116 | { |
117 | __uses_alloc_t<_Tp, _Alloc, _Args...> __ret; |
118 | __ret._M_a = std::__addressof(__a); |
119 | return __ret; |
120 | } |
121 | |
122 | template<typename _Tp, typename _Alloc, typename... _Args> |
123 | void |
124 | __use_alloc(const _Alloc&&) = delete; |
125 | |
126 | #if __cplusplus > 201402L |
127 | template <typename _Tp, typename _Alloc> |
128 | inline constexpr bool uses_allocator_v = |
129 | uses_allocator<_Tp, _Alloc>::value; |
130 | #endif // C++17 |
131 | |
132 | template<template<typename...> class _Predicate, |
133 | typename _Tp, typename _Alloc, typename... _Args> |
134 | struct __is_uses_allocator_predicate |
135 | : conditional<uses_allocator<_Tp, _Alloc>::value, |
136 | __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>, |
137 | _Predicate<_Tp, _Args..., _Alloc>>, |
138 | _Predicate<_Tp, _Args...>>::type { }; |
139 | |
140 | template<typename _Tp, typename _Alloc, typename... _Args> |
141 | struct __is_uses_allocator_constructible |
142 | : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...> |
143 | { }; |
144 | |
145 | #if __cplusplus >= 201402L |
146 | template<typename _Tp, typename _Alloc, typename... _Args> |
147 | _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v = |
148 | __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; |
149 | #endif // C++14 |
150 | |
151 | template<typename _Tp, typename _Alloc, typename... _Args> |
152 | struct __is_nothrow_uses_allocator_constructible |
153 | : __is_uses_allocator_predicate<is_nothrow_constructible, |
154 | _Tp, _Alloc, _Args...> |
155 | { }; |
156 | |
157 | |
158 | #if __cplusplus >= 201402L |
159 | template<typename _Tp, typename _Alloc, typename... _Args> |
160 | _GLIBCXX17_INLINE constexpr bool |
161 | __is_nothrow_uses_allocator_constructible_v = |
162 | __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; |
163 | #endif // C++14 |
164 | |
165 | template<typename _Tp, typename... _Args> |
166 | void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr, |
167 | _Args&&... __args) |
168 | { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); } |
169 | |
170 | template<typename _Tp, typename _Alloc, typename... _Args> |
171 | void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr, |
172 | _Args&&... __args) |
173 | { |
174 | ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a, |
175 | std::forward<_Args>(__args)...); |
176 | } |
177 | |
178 | template<typename _Tp, typename _Alloc, typename... _Args> |
179 | void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr, |
180 | _Args&&... __args) |
181 | { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); } |
182 | |
183 | template<typename _Tp, typename _Alloc, typename... _Args> |
184 | void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr, |
185 | _Args&&... __args) |
186 | { |
187 | std::__uses_allocator_construct_impl( |
188 | std::__use_alloc<_Tp, _Alloc, _Args...>(__a), __ptr, |
189 | std::forward<_Args>(__args)...); |
190 | } |
191 | |
192 | /// @endcond |
193 | _GLIBCXX_END_NAMESPACE_VERSION |
194 | } // namespace std |
195 | |
196 | #endif |
197 | #endif |
198 | |