libstdc++
enable_special_members.h
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1 // <bits/enable_special_members.h> -*- C++ -*-
2 
3 // Copyright (C) 2013-2020 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 namespace 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  */
49 template<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  */
73 template<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  */
81 template<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  */
93 template<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 
107 template<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 
125 template<typename _Tag>
126  struct _Enable_destructor<false, _Tag>
127  { ~_Enable_destructor() noexcept = delete; };
128 
129 template<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 
141 template<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 
153 template<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 
165 template<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 
177 template<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 
189 template<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 
201 template<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 
213 template<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 
225 template<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 
237 template<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 
249 template<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 
261 template<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 
273 template<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 
285 template<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 
297 template<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
std
ISO C++ entities toplevel namespace is std.
std::_Enable_default_constructor
A mixin helper to conditionally enable or disable the default constructor.
Definition: enable_special_members.h:51
std::_Enable_destructor
A mixin helper to conditionally enable or disable the default destructor.
Definition: enable_special_members.h:74
std::_Enable_copy_move
A mixin helper to conditionally enable or disable the copy/move special members.
Definition: enable_special_members.h:84
std::_Enable_special_members
A mixin helper to conditionally enable or disable the special members.
Definition: enable_special_members.h:103