libstdc++-v3/include/bits/enable_special_members.h

   1 // <bits/enable_special_members.h> -*- C++ -*-
   2
   3 // Copyright (C) 2013-2016 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 /**
  40   * @brief A mixin helper to conditionally enable or disable the default
  41   * constructor.
  42   * @sa _Enable_special_members
  43   */
  44 template<bool _Switch, typename _Tag = void>
  45   struct _Enable_default_constructor { };
  46
  47
  48 /**
  49   * @brief A mixin helper to conditionally enable or disable the default
  50   * destructor.
  51   * @sa _Enable_special_members
  52   */
  53 template<bool _Switch, typename _Tag = void>
  54   struct _Enable_destructor { };
  55
  56 /**
  57   * @brief A mixin helper to conditionally enable or disable the copy/move
  58   * special members.
  59   * @sa _Enable_special_members
  60   */
  61 template<bool _Copy, bool _CopyAssignment,
  62          bool _Move, bool _MoveAssignment,
  63          typename _Tag = void>
  64   struct _Enable_copy_move { };
  65
  66 /**
  67   * @brief A mixin helper to conditionally enable or disable the special
  68   * members.
  69   *
  70   * The @c _Tag type parameter is to make mixin bases unique and thus avoid
  71   * ambiguities.
  72   */
  73 template<bool _Default, bool _Destructor,
  74          bool _Copy, bool _CopyAssignment,
  75          bool _Move, bool _MoveAssignment,
  76          typename _Tag = void>
  77   struct _Enable_special_members
  78   : private _Enable_default_constructor<_Default, _Tag>,
  79     private _Enable_destructor<_Destructor, _Tag>,
  80     private _Enable_copy_move<_Copy, _CopyAssignment,
  81                               _Move, _MoveAssignment,
  82                               _Tag>
  83   { };
  84
  85 // Boilerplate follows.
  86
  87 template<typename _Tag>
  88   struct _Enable_default_constructor<false, _Tag>
  89   { constexpr _Enable_default_constructor() noexcept = delete; };
  90
  91 template<typename _Tag>
  92   struct _Enable_destructor<false, _Tag>
  93   { ~_Enable_destructor() noexcept = delete; };
  94
  95 template<typename _Tag>
  96   struct _Enable_copy_move<false, true, true, true, _Tag>
  97   {
  98     constexpr _Enable_copy_move() noexcept                          = default;
  99     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 100     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 101     _Enable_copy_move&
 102     operator=(_Enable_copy_move const&) noexcept                    = default;
 103     _Enable_copy_move&
 104     operator=(_Enable_copy_move&&) noexcept                         = default;
 105   };
 106
 107 template<typename _Tag>
 108   struct _Enable_copy_move<true, false, true, true, _Tag>
 109   {
 110     constexpr _Enable_copy_move() noexcept                          = default;
 111     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 112     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 113     _Enable_copy_move&
 114     operator=(_Enable_copy_move const&) noexcept                    = delete;
 115     _Enable_copy_move&
 116     operator=(_Enable_copy_move&&) noexcept                         = default;
 117   };
 118
 119 template<typename _Tag>
 120   struct _Enable_copy_move<false, false, true, true, _Tag>
 121   {
 122     constexpr _Enable_copy_move() noexcept                          = default;
 123     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 124     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 125     _Enable_copy_move&
 126     operator=(_Enable_copy_move const&) noexcept                    = delete;
 127     _Enable_copy_move&
 128     operator=(_Enable_copy_move&&) noexcept                         = default;
 129   };
 130
 131 template<typename _Tag>
 132   struct _Enable_copy_move<true, true, false, true, _Tag>
 133   {
 134     constexpr _Enable_copy_move() noexcept                          = default;
 135     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 136     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 137     _Enable_copy_move&
 138     operator=(_Enable_copy_move const&) noexcept                    = default;
 139     _Enable_copy_move&
 140     operator=(_Enable_copy_move&&) noexcept                         = default;
 141   };
 142
 143 template<typename _Tag>
 144   struct _Enable_copy_move<false, true, false, true, _Tag>
 145   {
 146     constexpr _Enable_copy_move() noexcept                          = default;
 147     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 148     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 149     _Enable_copy_move&
 150     operator=(_Enable_copy_move const&) noexcept                    = default;
 151     _Enable_copy_move&
 152     operator=(_Enable_copy_move&&) noexcept                         = default;
 153   };
 154
 155 template<typename _Tag>
 156   struct _Enable_copy_move<true, false, false, true, _Tag>
 157   {
 158     constexpr _Enable_copy_move() noexcept                          = default;
 159     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 160     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 161     _Enable_copy_move&
 162     operator=(_Enable_copy_move const&) noexcept                    = delete;
 163     _Enable_copy_move&
 164     operator=(_Enable_copy_move&&) noexcept                         = default;
 165   };
 166
 167 template<typename _Tag>
 168   struct _Enable_copy_move<false, false, false, true, _Tag>
 169   {
 170     constexpr _Enable_copy_move() noexcept                          = default;
 171     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 172     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 173     _Enable_copy_move&
 174     operator=(_Enable_copy_move const&) noexcept                    = delete;
 175     _Enable_copy_move&
 176     operator=(_Enable_copy_move&&) noexcept                         = default;
 177   };
 178
 179 template<typename _Tag>
 180   struct _Enable_copy_move<true, true, true, false, _Tag>
 181   {
 182     constexpr _Enable_copy_move() noexcept                          = default;
 183     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 184     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 185     _Enable_copy_move&
 186     operator=(_Enable_copy_move const&) noexcept                    = default;
 187     _Enable_copy_move&
 188     operator=(_Enable_copy_move&&) noexcept                         = delete;
 189   };
 190
 191 template<typename _Tag>
 192   struct _Enable_copy_move<false, true, true, false, _Tag>
 193   {
 194     constexpr _Enable_copy_move() noexcept                          = default;
 195     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 196     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 197     _Enable_copy_move&
 198     operator=(_Enable_copy_move const&) noexcept                    = default;
 199     _Enable_copy_move&
 200     operator=(_Enable_copy_move&&) noexcept                         = delete;
 201   };
 202
 203 template<typename _Tag>
 204   struct _Enable_copy_move<true, false, true, false, _Tag>
 205   {
 206     constexpr _Enable_copy_move() noexcept                          = default;
 207     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 208     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 209     _Enable_copy_move&
 210     operator=(_Enable_copy_move const&) noexcept                    = delete;
 211     _Enable_copy_move&
 212     operator=(_Enable_copy_move&&) noexcept                         = delete;
 213   };
 214
 215 template<typename _Tag>
 216   struct _Enable_copy_move<false, false, true, false, _Tag>
 217   {
 218     constexpr _Enable_copy_move() noexcept                          = default;
 219     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 220     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
 221     _Enable_copy_move&
 222     operator=(_Enable_copy_move const&) noexcept                    = delete;
 223     _Enable_copy_move&
 224     operator=(_Enable_copy_move&&) noexcept                         = delete;
 225   };
 226
 227 template<typename _Tag>
 228   struct _Enable_copy_move<true, true, false, false, _Tag>
 229   {
 230     constexpr _Enable_copy_move() noexcept                          = default;
 231     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 232     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 233     _Enable_copy_move&
 234     operator=(_Enable_copy_move const&) noexcept                    = default;
 235     _Enable_copy_move&
 236     operator=(_Enable_copy_move&&) noexcept                         = delete;
 237   };
 238
 239 template<typename _Tag>
 240   struct _Enable_copy_move<false, true, false, false, _Tag>
 241   {
 242     constexpr _Enable_copy_move() noexcept                          = default;
 243     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 244     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 245     _Enable_copy_move&
 246     operator=(_Enable_copy_move const&) noexcept                    = default;
 247     _Enable_copy_move&
 248     operator=(_Enable_copy_move&&) noexcept                         = delete;
 249   };
 250
 251 template<typename _Tag>
 252   struct _Enable_copy_move<true, false, false, false, _Tag>
 253   {
 254     constexpr _Enable_copy_move() noexcept                          = default;
 255     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
 256     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 257     _Enable_copy_move&
 258     operator=(_Enable_copy_move const&) noexcept                    = delete;
 259     _Enable_copy_move&
 260     operator=(_Enable_copy_move&&) noexcept                         = delete;
 261   };
 262
 263 template<typename _Tag>
 264   struct _Enable_copy_move<false, false, false, false, _Tag>
 265   {
 266     constexpr _Enable_copy_move() noexcept                          = default;
 267     constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
 268     constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
 269     _Enable_copy_move&
 270     operator=(_Enable_copy_move const&) noexcept                    = delete;
 271     _Enable_copy_move&
 272     operator=(_Enable_copy_move&&) noexcept                         = delete;
 273   };
 274
 275 _GLIBCXX_END_NAMESPACE_VERSION
 276 } // namespace std
 277
 278 #endif // _ENABLE_SPECIAL_MEMBERS_H