1// <bits/enable_special_members.h> -*- C++ -*-
2
3// Copyright (C) 2013-2021 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/** @file bits/enable_special_members.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly.
28 */
29
30#ifndef _ENABLE_SPECIAL_MEMBERS_H
31#define _ENABLE_SPECIAL_MEMBERS_H 1
32
33#pragma GCC system_header
34
35#include <bits/c++config.h>
36
37namespace std _GLIBCXX_VISIBILITY(default)
38{
39_GLIBCXX_BEGIN_NAMESPACE_VERSION
40/// @cond undocumented
41
42 struct _Enable_default_constructor_tag
43 {
44 explicit constexpr _Enable_default_constructor_tag() = default;
45 };
46
47/**
48 * @brief A mixin helper to conditionally enable or disable the default
49 * constructor.
50 * @sa _Enable_special_members
51 */
52template<bool _Switch, typename _Tag = void>
53 struct _Enable_default_constructor
54 {
55 constexpr _Enable_default_constructor() noexcept = default;
56 constexpr _Enable_default_constructor(_Enable_default_constructor const&)
57 noexcept = default;
58 constexpr _Enable_default_constructor(_Enable_default_constructor&&)
59 noexcept = default;
60 _Enable_default_constructor&
61 operator=(_Enable_default_constructor const&) noexcept = default;
62 _Enable_default_constructor&
63 operator=(_Enable_default_constructor&&) noexcept = default;
64
65 // Can be used in other ctors.
66 constexpr explicit
67 _Enable_default_constructor(_Enable_default_constructor_tag) { }
68 };
69
70
71/**
72 * @brief A mixin helper to conditionally enable or disable the default
73 * destructor.
74 * @sa _Enable_special_members
75 */
76template<bool _Switch, typename _Tag = void>
77 struct _Enable_destructor { };
78
79/**
80 * @brief A mixin helper to conditionally enable or disable the copy/move
81 * special members.
82 * @sa _Enable_special_members
83 */
84template<bool _Copy, bool _CopyAssignment,
85 bool _Move, bool _MoveAssignment,
86 typename _Tag = void>
87 struct _Enable_copy_move { };
88
89/**
90 * @brief A mixin helper to conditionally enable or disable the special
91 * members.
92 *
93 * The @c _Tag type parameter is to make mixin bases unique and thus avoid
94 * ambiguities.
95 */
96template<bool _Default, bool _Destructor,
97 bool _Copy, bool _CopyAssignment,
98 bool _Move, bool _MoveAssignment,
99 typename _Tag = void>
100 struct _Enable_special_members
101 : private _Enable_default_constructor<_Default, _Tag>,
102 private _Enable_destructor<_Destructor, _Tag>,
103 private _Enable_copy_move<_Copy, _CopyAssignment,
104 _Move, _MoveAssignment,
105 _Tag>
106 { };
107
108// Boilerplate follows.
109
110template<typename _Tag>
111 struct _Enable_default_constructor<false, _Tag>
112 {
113 constexpr _Enable_default_constructor() noexcept = delete;
114 constexpr _Enable_default_constructor(_Enable_default_constructor const&)
115 noexcept = default;
116 constexpr _Enable_default_constructor(_Enable_default_constructor&&)
117 noexcept = default;
118 _Enable_default_constructor&
119 operator=(_Enable_default_constructor const&) noexcept = default;
120 _Enable_default_constructor&
121 operator=(_Enable_default_constructor&&) noexcept = default;
122
123 // Can be used in other ctors.
124 constexpr explicit
125 _Enable_default_constructor(_Enable_default_constructor_tag) { }
126 };
127
128template<typename _Tag>
129 struct _Enable_destructor<false, _Tag>
130 { ~_Enable_destructor() noexcept = delete; };
131
132template<typename _Tag>
133 struct _Enable_copy_move<false, true, true, true, _Tag>
134 {
135 constexpr _Enable_copy_move() noexcept = default;
136 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
137 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
138 _Enable_copy_move&
139 operator=(_Enable_copy_move const&) noexcept = default;
140 _Enable_copy_move&
141 operator=(_Enable_copy_move&&) noexcept = default;
142 };
143
144template<typename _Tag>
145 struct _Enable_copy_move<true, false, true, true, _Tag>
146 {
147 constexpr _Enable_copy_move() noexcept = default;
148 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
149 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
150 _Enable_copy_move&
151 operator=(_Enable_copy_move const&) noexcept = delete;
152 _Enable_copy_move&
153 operator=(_Enable_copy_move&&) noexcept = default;
154 };
155
156template<typename _Tag>
157 struct _Enable_copy_move<false, false, true, true, _Tag>
158 {
159 constexpr _Enable_copy_move() noexcept = default;
160 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
161 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
162 _Enable_copy_move&
163 operator=(_Enable_copy_move const&) noexcept = delete;
164 _Enable_copy_move&
165 operator=(_Enable_copy_move&&) noexcept = default;
166 };
167
168template<typename _Tag>
169 struct _Enable_copy_move<true, true, false, true, _Tag>
170 {
171 constexpr _Enable_copy_move() noexcept = default;
172 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
173 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
174 _Enable_copy_move&
175 operator=(_Enable_copy_move const&) noexcept = default;
176 _Enable_copy_move&
177 operator=(_Enable_copy_move&&) noexcept = default;
178 };
179
180template<typename _Tag>
181 struct _Enable_copy_move<false, true, false, true, _Tag>
182 {
183 constexpr _Enable_copy_move() noexcept = default;
184 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
185 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
186 _Enable_copy_move&
187 operator=(_Enable_copy_move const&) noexcept = default;
188 _Enable_copy_move&
189 operator=(_Enable_copy_move&&) noexcept = default;
190 };
191
192template<typename _Tag>
193 struct _Enable_copy_move<true, false, false, true, _Tag>
194 {
195 constexpr _Enable_copy_move() noexcept = default;
196 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
197 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
198 _Enable_copy_move&
199 operator=(_Enable_copy_move const&) noexcept = delete;
200 _Enable_copy_move&
201 operator=(_Enable_copy_move&&) noexcept = default;
202 };
203
204template<typename _Tag>
205 struct _Enable_copy_move<false, false, false, true, _Tag>
206 {
207 constexpr _Enable_copy_move() noexcept = default;
208 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
209 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
210 _Enable_copy_move&
211 operator=(_Enable_copy_move const&) noexcept = delete;
212 _Enable_copy_move&
213 operator=(_Enable_copy_move&&) noexcept = default;
214 };
215
216template<typename _Tag>
217 struct _Enable_copy_move<true, true, true, false, _Tag>
218 {
219 constexpr _Enable_copy_move() noexcept = default;
220 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
221 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
222 _Enable_copy_move&
223 operator=(_Enable_copy_move const&) noexcept = default;
224 _Enable_copy_move&
225 operator=(_Enable_copy_move&&) noexcept = delete;
226 };
227
228template<typename _Tag>
229 struct _Enable_copy_move<false, true, true, false, _Tag>
230 {
231 constexpr _Enable_copy_move() noexcept = default;
232 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
233 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
234 _Enable_copy_move&
235 operator=(_Enable_copy_move const&) noexcept = default;
236 _Enable_copy_move&
237 operator=(_Enable_copy_move&&) noexcept = delete;
238 };
239
240template<typename _Tag>
241 struct _Enable_copy_move<true, false, true, false, _Tag>
242 {
243 constexpr _Enable_copy_move() noexcept = default;
244 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
245 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
246 _Enable_copy_move&
247 operator=(_Enable_copy_move const&) noexcept = delete;
248 _Enable_copy_move&
249 operator=(_Enable_copy_move&&) noexcept = delete;
250 };
251
252template<typename _Tag>
253 struct _Enable_copy_move<false, false, true, false, _Tag>
254 {
255 constexpr _Enable_copy_move() noexcept = default;
256 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
257 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default;
258 _Enable_copy_move&
259 operator=(_Enable_copy_move const&) noexcept = delete;
260 _Enable_copy_move&
261 operator=(_Enable_copy_move&&) noexcept = delete;
262 };
263
264template<typename _Tag>
265 struct _Enable_copy_move<true, true, false, false, _Tag>
266 {
267 constexpr _Enable_copy_move() noexcept = default;
268 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
269 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
270 _Enable_copy_move&
271 operator=(_Enable_copy_move const&) noexcept = default;
272 _Enable_copy_move&
273 operator=(_Enable_copy_move&&) noexcept = delete;
274 };
275
276template<typename _Tag>
277 struct _Enable_copy_move<false, true, false, false, _Tag>
278 {
279 constexpr _Enable_copy_move() noexcept = default;
280 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
281 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
282 _Enable_copy_move&
283 operator=(_Enable_copy_move const&) noexcept = default;
284 _Enable_copy_move&
285 operator=(_Enable_copy_move&&) noexcept = delete;
286 };
287
288template<typename _Tag>
289 struct _Enable_copy_move<true, false, false, false, _Tag>
290 {
291 constexpr _Enable_copy_move() noexcept = default;
292 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default;
293 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
294 _Enable_copy_move&
295 operator=(_Enable_copy_move const&) noexcept = delete;
296 _Enable_copy_move&
297 operator=(_Enable_copy_move&&) noexcept = delete;
298 };
299
300template<typename _Tag>
301 struct _Enable_copy_move<false, false, false, false, _Tag>
302 {
303 constexpr _Enable_copy_move() noexcept = default;
304 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete;
305 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete;
306 _Enable_copy_move&
307 operator=(_Enable_copy_move const&) noexcept = delete;
308 _Enable_copy_move&
309 operator=(_Enable_copy_move&&) noexcept = delete;
310 };
311
312/// @endcond
313_GLIBCXX_END_NAMESPACE_VERSION
314} // namespace std
315
316#endif // _ENABLE_SPECIAL_MEMBERS_H
317

source code of include/c++/11/bits/enable_special_members.h