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

   1 // unique_ptr implementation -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009, 2010 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 unique_ptr.h
  26  *  This is an internal header file, included by other library headers.
  27  *  You should not attempt to use it directly.
  28  */
  29
  30 #ifndef _UNIQUE_PTR_H
  31 #define _UNIQUE_PTR_H 1
  32
  33 #include <bits/c++config.h>
  34 #include <debug/debug.h>
  35 #include <type_traits>
  36 #include <utility>
  37 #include <tuple>
  38
  39 _GLIBCXX_BEGIN_NAMESPACE(std)
  40
  41   /**
  42    * @addtogroup pointer_abstractions
  43    * @{
  44    */
  45
  46   /// Primary template, default_delete.
  47   template<typename _Tp>
  48     struct default_delete
  49       {
  50         default_delete() { }
  51
  52         template<typename _Up>
  53           default_delete(const default_delete<_Up>&) { }
  54
  55         void
  56         operator()(_Tp* __ptr) const
  57         {
  58           static_assert(sizeof(_Tp)>0,
  59                         "can't delete pointer to incomplete type");
  60           delete __ptr;
  61         }
  62     };
  63
  64   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  65   // DR 740 - omit specialization for array objects with a compile time length
  66   /// Specialization, default_delete.
  67   template<typename _Tp>
  68     struct default_delete<_Tp[]>
  69     {
  70       void
  71       operator()(_Tp* __ptr) const
  72       {
  73         static_assert(sizeof(_Tp)>0,
  74                       "can't delete pointer to incomplete type");
  75         delete [] __ptr;
  76       }
  77     };
  78
  79   /// 20.7.12.2 unique_ptr for single objects.
  80   template <typename _Tp, typename _Tp_Deleter = default_delete<_Tp> >
  81     class unique_ptr
  82     {
  83       typedef std::tuple<_Tp*, _Tp_Deleter>  __tuple_type;
  84       typedef _Tp* unique_ptr::*             __unspecified_pointer_type;
  85
  86     public:
  87       typedef _Tp*               pointer;
  88       typedef _Tp                element_type;
  89       typedef _Tp_Deleter        deleter_type;
  90
  91       // Constructors.
  92       unique_ptr()
  93       : _M_t(pointer(), deleter_type())
  94       { static_assert(!std::is_pointer<deleter_type>::value,
  95                       "constructed with null function pointer deleter"); }
  96
  97       explicit
  98       unique_ptr(pointer __p)
  99       : _M_t(__p, deleter_type())
 100       { static_assert(!std::is_pointer<deleter_type>::value,
 101                      "constructed with null function pointer deleter"); }
 102
 103       unique_ptr(pointer __p,
 104           typename std::conditional<std::is_reference<deleter_type>::value,
 105             deleter_type, const deleter_type&>::type __d)
 106       : _M_t(__p, __d) { }
 107
 108       unique_ptr(pointer __p,
 109           typename std::remove_reference<deleter_type>::type&& __d)
 110       : _M_t(std::move(__p), std::move(__d))
 111       { static_assert(!std::is_reference<deleter_type>::value,
 112                       "rvalue deleter bound to reference"); }
 113
 114       // Move constructors.
 115       unique_ptr(unique_ptr&& __u)
 116       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 117
 118       template<typename _Up, typename _Up_Deleter>
 119         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 120         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 121         { }
 122
 123       // Destructor.
 124       ~unique_ptr() { reset(); }
 125
 126       // Assignment.
 127       unique_ptr&
 128       operator=(unique_ptr&& __u)
 129       {
 130         reset(__u.release());
 131         get_deleter() = std::move(__u.get_deleter());
 132         return *this;
 133       }
 134
 135       template<typename _Up, typename _Up_Deleter>
 136         unique_ptr&
 137         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 138         {
 139           reset(__u.release());
 140           get_deleter() = std::move(__u.get_deleter());
 141           return *this;
 142         }
 143
 144       unique_ptr&
 145       operator=(__unspecified_pointer_type)
 146       {
 147         reset();
 148         return *this;
 149       }
 150
 151       // Observers.
 152       typename std::add_lvalue_reference<element_type>::type
 153       operator*() const
 154       {
 155         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 156         return *get();
 157       }
 158
 159       pointer
 160       operator->() const
 161       {
 162         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 163         return get();
 164       }
 165
 166       pointer
 167       get() const
 168       { return std::get<0>(_M_t); }
 169
 170       typename std::add_lvalue_reference<deleter_type>::type
 171       get_deleter()
 172       { return std::get<1>(_M_t); }
 173
 174       typename std::add_lvalue_reference<
 175           typename std::add_const<deleter_type>::type
 176               >::type
 177       get_deleter() const
 178       { return std::get<1>(_M_t); }
 179
 180       explicit operator bool() const
 181       { return get() == 0 ? false : true; }
 182
 183       // Modifiers.
 184       pointer
 185       release()
 186       {
 187         pointer __p = get();
 188         std::get<0>(_M_t) = 0;
 189         return __p;
 190       }
 191
 192       void
 193       reset(pointer __p = pointer())
 194       {
 195         if (__p != get())
 196           {
 197             get_deleter()(get());
 198             std::get<0>(_M_t) = __p;
 199           }
 200       }
 201
 202       void
 203       swap(unique_ptr& __u)
 204       {
 205         using std::swap;
 206         swap(_M_t, __u._M_t);
 207       }
 208
 209       // Disable copy from lvalue.
 210       unique_ptr(const unique_ptr&) = delete;
 211       unique_ptr& operator=(const unique_ptr&) = delete;
 212
 213     private:
 214       __tuple_type _M_t;
 215   };
 216
 217   /// 20.7.12.3 unique_ptr for array objects with a runtime length
 218   // [unique.ptr.runtime]
 219   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 220   // DR 740 - omit specialization for array objects with a compile time length
 221   template<typename _Tp, typename _Tp_Deleter>
 222     class unique_ptr<_Tp[], _Tp_Deleter>
 223     {
 224       typedef std::tuple<_Tp*, _Tp_Deleter>  __tuple_type;
 225       typedef _Tp* unique_ptr::*             __unspecified_pointer_type;
 226
 227     public:
 228       typedef _Tp*               pointer;
 229       typedef _Tp                element_type;
 230       typedef _Tp_Deleter        deleter_type;
 231
 232       // Constructors.
 233       unique_ptr()
 234       : _M_t(pointer(), deleter_type())
 235       { static_assert(!std::is_pointer<deleter_type>::value,
 236                       "constructed with null function pointer deleter"); }
 237
 238       explicit
 239       unique_ptr(pointer __p)
 240       : _M_t(__p, deleter_type())
 241       { static_assert(!std::is_pointer<deleter_type>::value,
 242                       "constructed with null function pointer deleter"); }
 243
 244       unique_ptr(pointer __p,
 245           typename std::conditional<std::is_reference<deleter_type>::value,
 246               deleter_type, const deleter_type&>::type __d)
 247       : _M_t(__p, __d) { }
 248
 249       unique_ptr(pointer __p,
 250                  typename std::remove_reference<deleter_type>::type && __d)
 251       : _M_t(std::move(__p), std::move(__d))
 252       { static_assert(!std::is_reference<deleter_type>::value,
 253                       "rvalue deleter bound to reference"); }
 254
 255       // Move constructors.
 256       unique_ptr(unique_ptr&& __u)
 257       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 258
 259       template<typename _Up, typename _Up_Deleter>
 260         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 261         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 262         { }
 263
 264       // Destructor.
 265       ~unique_ptr() { reset(); }
 266
 267       // Assignment.
 268       unique_ptr&
 269       operator=(unique_ptr&& __u)
 270       {
 271         reset(__u.release());
 272         get_deleter() = std::move(__u.get_deleter());
 273         return *this;
 274       }
 275
 276       template<typename _Up, typename _Up_Deleter>
 277         unique_ptr&
 278         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 279         {
 280           reset(__u.release());
 281           get_deleter() = std::move(__u.get_deleter());
 282           return *this;
 283         }
 284
 285       unique_ptr&
 286       operator=(__unspecified_pointer_type)
 287       {
 288         reset();
 289         return *this;
 290       }
 291
 292       // Observers.
 293       typename std::add_lvalue_reference<element_type>::type
 294       operator[](size_t __i) const
 295       {
 296         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 297         return get()[__i];
 298       }
 299
 300       pointer
 301       get() const
 302       { return std::get<0>(_M_t); }
 303
 304       typename std::add_lvalue_reference<deleter_type>::type
 305       get_deleter()
 306       { return std::get<1>(_M_t); }
 307
 308       typename std::add_lvalue_reference<
 309           typename std::add_const<deleter_type>::type
 310               >::type
 311       get_deleter() const
 312       { return std::get<1>(_M_t); }
 313
 314       explicit operator bool() const
 315       { return get() == 0 ? false : true; }
 316
 317       // Modifiers.
 318       pointer
 319       release()
 320       {
 321         pointer __p = get();
 322         std::get<0>(_M_t) = 0;
 323         return __p;
 324       }
 325
 326       void
 327       reset(pointer __p = pointer())
 328       {
 329         if (__p != get())
 330         {
 331           get_deleter()(get());
 332           std::get<0>(_M_t) = __p;
 333         }
 334       }
 335
 336       // DR 821.
 337       template<typename _Up>
 338         void reset(_Up) = delete;
 339
 340       void
 341       swap(unique_ptr& __u)
 342       {
 343         using std::swap;
 344         swap(_M_t, __u._M_t);
 345       }
 346
 347       // Disable copy from lvalue.
 348       unique_ptr(const unique_ptr&) = delete;
 349       unique_ptr& operator=(const unique_ptr&) = delete;
 350
 351       // Disable construction from convertible pointer types.
 352       // (N2315 - 20.6.5.3.1)
 353       template<typename _Up>
 354         unique_ptr(_Up*, typename
 355                    std::conditional<std::is_reference<deleter_type>::value,
 356                    deleter_type, const deleter_type&>::type,
 357                    typename std::enable_if<std::is_convertible<_Up*,
 358                    pointer>::value>::type* = 0) = delete;
 359
 360       template<typename _Up>
 361         unique_ptr(_Up*, typename std::remove_reference<deleter_type>::type&&,
 362                    typename std::enable_if<std::is_convertible<_Up*,
 363                    pointer>::value>::type* = 0) = delete;
 364
 365       template<typename _Up>
 366         explicit
 367         unique_ptr(_Up*, typename std::enable_if<std::is_convertible<_Up*,
 368                    pointer>::value>::type* = 0) = delete;
 369
 370     private:
 371       __tuple_type _M_t;
 372   };
 373
 374   template<typename _Tp, typename _Tp_Deleter>
 375     inline void
 376     swap(unique_ptr<_Tp, _Tp_Deleter>& __x,
 377          unique_ptr<_Tp, _Tp_Deleter>& __y)
 378     { __x.swap(__y); }
 379
 380   template<typename _Tp, typename _Tp_Deleter,
 381            typename _Up, typename _Up_Deleter>
 382     inline bool
 383     operator==(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 384                const unique_ptr<_Up, _Up_Deleter>& __y)
 385     { return __x.get() == __y.get(); }
 386
 387   template<typename _Tp, typename _Tp_Deleter,
 388            typename _Up, typename _Up_Deleter>
 389     inline bool
 390     operator!=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 391                const unique_ptr<_Up, _Up_Deleter>& __y)
 392     { return !(__x.get() == __y.get()); }
 393
 394   template<typename _Tp, typename _Tp_Deleter,
 395            typename _Up, typename _Up_Deleter>
 396     inline bool
 397     operator<(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 398               const unique_ptr<_Up, _Up_Deleter>& __y)
 399     { return __x.get() < __y.get(); }
 400
 401   template<typename _Tp, typename _Tp_Deleter,
 402            typename _Up, typename _Up_Deleter>
 403     inline bool
 404     operator<=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 405                const unique_ptr<_Up, _Up_Deleter>& __y)
 406     { return !(__y.get() < __x.get()); }
 407
 408   template<typename _Tp, typename _Tp_Deleter,
 409            typename _Up, typename _Up_Deleter>
 410     inline bool
 411     operator>(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 412               const unique_ptr<_Up, _Up_Deleter>& __y)
 413     { return __y.get() < __x.get(); }
 414
 415   template<typename _Tp, typename _Tp_Deleter,
 416            typename _Up, typename _Up_Deleter>
 417     inline bool
 418     operator>=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 419                const unique_ptr<_Up, _Up_Deleter>& __y)
 420     { return !(__x.get() < __y.get()); }
 421
 422   // @} group pointer_abstractions
 423
 424 _GLIBCXX_END_NAMESPACE
 425
 426 #endif /* _UNIQUE_PTR_H */