1// <bits/enable_special_members.h> -*- C++ -*- 
2 
3// Copyright (C) 2013-2019 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 
35namespace std _GLIBCXX_VISIBILITY(default) 
36{ 
37_GLIBCXX_BEGIN_NAMESPACE_VERSION 
38 
39 struct _Enable_default_constructor_tag 
40 { 
41 explicit constexpr _Enable_default_constructor_tag() = default; 
42 }; 
43 
44/** 
45 * @brief A mixin helper to conditionally enable or disable the default 
46 * constructor. 
47 * @sa _Enable_special_members 
48 */ 
49template<bool _Switch, typename _Tag = void> 
50 struct _Enable_default_constructor 
51 { 
52 constexpr _Enable_default_constructor() noexcept = default; 
53 constexpr _Enable_default_constructor(_Enable_default_constructor const&) 
54 noexcept = default; 
55 constexpr _Enable_default_constructor(_Enable_default_constructor&&) 
56 noexcept = default; 
57 _Enable_default_constructor& 
58 operator=(_Enable_default_constructor const&) noexcept = default; 
59 _Enable_default_constructor& 
60 operator=(_Enable_default_constructor&&) noexcept = default; 
61 
62 // Can be used in other ctors. 
63 constexpr explicit 
64 _Enable_default_constructor(_Enable_default_constructor_tag) { } 
65 }; 
66 
67 
68/** 
69 * @brief A mixin helper to conditionally enable or disable the default 
70 * destructor. 
71 * @sa _Enable_special_members 
72 */ 
73template<bool _Switch, typename _Tag = void> 
74 struct _Enable_destructor { }; 
75 
76/** 
77 * @brief A mixin helper to conditionally enable or disable the copy/move 
78 * special members. 
79 * @sa _Enable_special_members 
80 */ 
81template<bool _Copy, bool _CopyAssignment, 
82 bool _Move, bool _MoveAssignment, 
83 typename _Tag = void> 
84 struct _Enable_copy_move { }; 
85 
86/** 
87 * @brief A mixin helper to conditionally enable or disable the special 
88 * members. 
89 * 
90 * The @c _Tag type parameter is to make mixin bases unique and thus avoid 
91 * ambiguities. 
92 */ 
93template<bool _Default, bool _Destructor, 
94 bool _Copy, bool _CopyAssignment, 
95 bool _Move, bool _MoveAssignment, 
96 typename _Tag = void> 
97 struct _Enable_special_members 
98 : private _Enable_default_constructor<_Default, _Tag>, 
99 private _Enable_destructor<_Destructor, _Tag>, 
100 private _Enable_copy_move<_Copy, _CopyAssignment, 
101 _Move, _MoveAssignment, 
102 _Tag> 
103 { }; 
104 
105// Boilerplate follows. 
106 
107template<typename _Tag> 
108 struct _Enable_default_constructor<false, _Tag> 
109 { 
110 constexpr _Enable_default_constructor() noexcept = delete; 
111 constexpr _Enable_default_constructor(_Enable_default_constructor const&) 
112 noexcept = default; 
113 constexpr _Enable_default_constructor(_Enable_default_constructor&&) 
114 noexcept = default; 
115 _Enable_default_constructor& 
116 operator=(_Enable_default_constructor const&) noexcept = default; 
117 _Enable_default_constructor& 
118 operator=(_Enable_default_constructor&&) noexcept = default; 
119 
120 // Can be used in other ctors. 
121 constexpr explicit 
122 _Enable_default_constructor(_Enable_default_constructor_tag) { } 
123 }; 
124 
125template<typename _Tag> 
126 struct _Enable_destructor<false, _Tag> 
127 { ~_Enable_destructor() noexcept = delete; }; 
128 
129template<typename _Tag> 
130 struct _Enable_copy_move<false, true, true, true, _Tag> 
131 { 
132 constexpr _Enable_copy_move() noexcept = default; 
133 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
134 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
135 _Enable_copy_move& 
136 operator=(_Enable_copy_move const&) noexcept = default; 
137 _Enable_copy_move& 
138 operator=(_Enable_copy_move&&) noexcept = default; 
139 }; 
140 
141template<typename _Tag> 
142 struct _Enable_copy_move<true, false, true, true, _Tag> 
143 { 
144 constexpr _Enable_copy_move() noexcept = default; 
145 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
146 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
147 _Enable_copy_move& 
148 operator=(_Enable_copy_move const&) noexcept = delete; 
149 _Enable_copy_move& 
150 operator=(_Enable_copy_move&&) noexcept = default; 
151 }; 
152 
153template<typename _Tag> 
154 struct _Enable_copy_move<false, false, true, true, _Tag> 
155 { 
156 constexpr _Enable_copy_move() noexcept = default; 
157 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
158 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
159 _Enable_copy_move& 
160 operator=(_Enable_copy_move const&) noexcept = delete; 
161 _Enable_copy_move& 
162 operator=(_Enable_copy_move&&) noexcept = default; 
163 }; 
164 
165template<typename _Tag> 
166 struct _Enable_copy_move<true, true, false, true, _Tag> 
167 { 
168 constexpr _Enable_copy_move() noexcept = default; 
169 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
170 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
171 _Enable_copy_move& 
172 operator=(_Enable_copy_move const&) noexcept = default; 
173 _Enable_copy_move& 
174 operator=(_Enable_copy_move&&) noexcept = default; 
175 }; 
176 
177template<typename _Tag> 
178 struct _Enable_copy_move<false, true, false, true, _Tag> 
179 { 
180 constexpr _Enable_copy_move() noexcept = default; 
181 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
182 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
183 _Enable_copy_move& 
184 operator=(_Enable_copy_move const&) noexcept = default; 
185 _Enable_copy_move& 
186 operator=(_Enable_copy_move&&) noexcept = default; 
187 }; 
188 
189template<typename _Tag> 
190 struct _Enable_copy_move<true, false, false, true, _Tag> 
191 { 
192 constexpr _Enable_copy_move() noexcept = default; 
193 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
194 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
195 _Enable_copy_move& 
196 operator=(_Enable_copy_move const&) noexcept = delete; 
197 _Enable_copy_move& 
198 operator=(_Enable_copy_move&&) noexcept = default; 
199 }; 
200 
201template<typename _Tag> 
202 struct _Enable_copy_move<false, false, false, true, _Tag> 
203 { 
204 constexpr _Enable_copy_move() noexcept = default; 
205 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
206 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
207 _Enable_copy_move& 
208 operator=(_Enable_copy_move const&) noexcept = delete; 
209 _Enable_copy_move& 
210 operator=(_Enable_copy_move&&) noexcept = default; 
211 }; 
212 
213template<typename _Tag> 
214 struct _Enable_copy_move<true, true, true, false, _Tag> 
215 { 
216 constexpr _Enable_copy_move() noexcept = default; 
217 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
218 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
219 _Enable_copy_move& 
220 operator=(_Enable_copy_move const&) noexcept = default; 
221 _Enable_copy_move& 
222 operator=(_Enable_copy_move&&) noexcept = delete; 
223 }; 
224 
225template<typename _Tag> 
226 struct _Enable_copy_move<false, true, true, false, _Tag> 
227 { 
228 constexpr _Enable_copy_move() noexcept = default; 
229 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
230 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
231 _Enable_copy_move& 
232 operator=(_Enable_copy_move const&) noexcept = default; 
233 _Enable_copy_move& 
234 operator=(_Enable_copy_move&&) noexcept = delete; 
235 }; 
236 
237template<typename _Tag> 
238 struct _Enable_copy_move<true, false, true, false, _Tag> 
239 { 
240 constexpr _Enable_copy_move() noexcept = default; 
241 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
242 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
243 _Enable_copy_move& 
244 operator=(_Enable_copy_move const&) noexcept = delete; 
245 _Enable_copy_move& 
246 operator=(_Enable_copy_move&&) noexcept = delete; 
247 }; 
248 
249template<typename _Tag> 
250 struct _Enable_copy_move<false, false, true, false, _Tag> 
251 { 
252 constexpr _Enable_copy_move() noexcept = default; 
253 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
254 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = default; 
255 _Enable_copy_move& 
256 operator=(_Enable_copy_move const&) noexcept = delete; 
257 _Enable_copy_move& 
258 operator=(_Enable_copy_move&&) noexcept = delete; 
259 }; 
260 
261template<typename _Tag> 
262 struct _Enable_copy_move<true, true, false, false, _Tag> 
263 { 
264 constexpr _Enable_copy_move() noexcept = default; 
265 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
266 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
267 _Enable_copy_move& 
268 operator=(_Enable_copy_move const&) noexcept = default; 
269 _Enable_copy_move& 
270 operator=(_Enable_copy_move&&) noexcept = delete; 
271 }; 
272 
273template<typename _Tag> 
274 struct _Enable_copy_move<false, true, false, false, _Tag> 
275 { 
276 constexpr _Enable_copy_move() noexcept = default; 
277 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
278 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
279 _Enable_copy_move& 
280 operator=(_Enable_copy_move const&) noexcept = default; 
281 _Enable_copy_move& 
282 operator=(_Enable_copy_move&&) noexcept = delete; 
283 }; 
284 
285template<typename _Tag> 
286 struct _Enable_copy_move<true, false, false, false, _Tag> 
287 { 
288 constexpr _Enable_copy_move() noexcept = default; 
289 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = default; 
290 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
291 _Enable_copy_move& 
292 operator=(_Enable_copy_move const&) noexcept = delete; 
293 _Enable_copy_move& 
294 operator=(_Enable_copy_move&&) noexcept = delete; 
295 }; 
296 
297template<typename _Tag> 
298 struct _Enable_copy_move<false, false, false, false, _Tag> 
299 { 
300 constexpr _Enable_copy_move() noexcept = default; 
301 constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept = delete; 
302 constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept = delete; 
303 _Enable_copy_move& 
304 operator=(_Enable_copy_move const&) noexcept = delete; 
305 _Enable_copy_move& 
306 operator=(_Enable_copy_move&&) noexcept = delete; 
307 }; 
308 
309_GLIBCXX_END_NAMESPACE_VERSION 
310} // namespace std 
311 
312#endif // _ENABLE_SPECIAL_MEMBERS_H 
313