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() != pointer());
 156         return *get();
 157       }
 158
 159       pointer
 160       operator->() const
 161       {
 162         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 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() == pointer() ? false : true; }
 182
 183       // Modifiers.
 184       pointer
 185       release()
 186       {
 187         pointer __p = get();
 188         std::get<0>(_M_t) = pointer();
 189         return __p;
 190       }
 191
 192       void
 193       reset(pointer __p = pointer())
 194       {
 195         using std::swap;
 196         swap(std::get<0>(_M_t), __p);
 197         if (__p != pointer())
 198           get_deleter()(__p);
 199       }
 200
 201       void
 202       swap(unique_ptr& __u)
 203       {
 204         using std::swap;
 205         swap(_M_t, __u._M_t);
 206       }
 207
 208       // Disable copy from lvalue.
 209       unique_ptr(const unique_ptr&) = delete;
 210       unique_ptr& operator=(const unique_ptr&) = delete;
 211
 212     private:
 213       __tuple_type _M_t;
 214   };
 215
 216   /// 20.7.12.3 unique_ptr for array objects with a runtime length
 217   // [unique.ptr.runtime]
 218   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 219   // DR 740 - omit specialization for array objects with a compile time length
 220   template<typename _Tp, typename _Tp_Deleter>
 221     class unique_ptr<_Tp[], _Tp_Deleter>
 222     {
 223       typedef std::tuple<_Tp*, _Tp_Deleter>  __tuple_type;
 224       typedef _Tp* unique_ptr::*             __unspecified_pointer_type;
 225
 226     public:
 227       typedef _Tp*               pointer;
 228       typedef _Tp                element_type;
 229       typedef _Tp_Deleter        deleter_type;
 230
 231       // Constructors.
 232       unique_ptr()
 233       : _M_t(pointer(), deleter_type())
 234       { static_assert(!std::is_pointer<deleter_type>::value,
 235                       "constructed with null function pointer deleter"); }
 236
 237       explicit
 238       unique_ptr(pointer __p)
 239       : _M_t(__p, deleter_type())
 240       { static_assert(!std::is_pointer<deleter_type>::value,
 241                       "constructed with null function pointer deleter"); }
 242
 243       unique_ptr(pointer __p,
 244           typename std::conditional<std::is_reference<deleter_type>::value,
 245               deleter_type, const deleter_type&>::type __d)
 246       : _M_t(__p, __d) { }
 247
 248       unique_ptr(pointer __p,
 249                  typename std::remove_reference<deleter_type>::type && __d)
 250       : _M_t(std::move(__p), std::move(__d))
 251       { static_assert(!std::is_reference<deleter_type>::value,
 252                       "rvalue deleter bound to reference"); }
 253
 254       // Move constructors.
 255       unique_ptr(unique_ptr&& __u)
 256       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 257
 258       template<typename _Up, typename _Up_Deleter>
 259         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 260         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 261         { }
 262
 263       // Destructor.
 264       ~unique_ptr() { reset(); }
 265
 266       // Assignment.
 267       unique_ptr&
 268       operator=(unique_ptr&& __u)
 269       {
 270         reset(__u.release());
 271         get_deleter() = std::move(__u.get_deleter());
 272         return *this;
 273       }
 274
 275       template<typename _Up, typename _Up_Deleter>
 276         unique_ptr&
 277         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 278         {
 279           reset(__u.release());
 280           get_deleter() = std::move(__u.get_deleter());
 281           return *this;
 282         }
 283
 284       unique_ptr&
 285       operator=(__unspecified_pointer_type)
 286       {
 287         reset();
 288         return *this;
 289       }
 290
 291       // Observers.
 292       typename std::add_lvalue_reference<element_type>::type
 293       operator[](size_t __i) const
 294       {
 295         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 296         return get()[__i];
 297       }
 298
 299       pointer
 300       get() const
 301       { return std::get<0>(_M_t); }
 302
 303       typename std::add_lvalue_reference<deleter_type>::type
 304       get_deleter()
 305       { return std::get<1>(_M_t); }
 306
 307       typename std::add_lvalue_reference<
 308           typename std::add_const<deleter_type>::type
 309               >::type
 310       get_deleter() const
 311       { return std::get<1>(_M_t); }
 312
 313       explicit operator bool() const
 314       { return get() == pointer() ? false : true; }
 315
 316       // Modifiers.
 317       pointer
 318       release()
 319       {
 320         pointer __p = get();
 321         std::get<0>(_M_t) = pointer();
 322         return __p;
 323       }
 324
 325       void
 326       reset(pointer __p = pointer())
 327       {
 328         using std::swap;
 329         swap(std::get<0>(_M_t), __p);
 330         if (__p != pointer())
 331           get_deleter()(__p);
 332       }
 333
 334       // DR 821.
 335       template<typename _Up>
 336         void reset(_Up) = delete;
 337
 338       void
 339       swap(unique_ptr& __u)
 340       {
 341         using std::swap;
 342         swap(_M_t, __u._M_t);
 343       }
 344
 345       // Disable copy from lvalue.
 346       unique_ptr(const unique_ptr&) = delete;
 347       unique_ptr& operator=(const unique_ptr&) = delete;
 348
 349       // Disable construction from convertible pointer types.
 350       // (N2315 - 20.6.5.3.1)
 351       template<typename _Up>
 352         unique_ptr(_Up*, typename
 353                    std::conditional<std::is_reference<deleter_type>::value,
 354                    deleter_type, const deleter_type&>::type,
 355                    typename std::enable_if<std::is_convertible<_Up*,
 356                    pointer>::value>::type* = 0) = delete;
 357
 358       template<typename _Up>
 359         unique_ptr(_Up*, typename std::remove_reference<deleter_type>::type&&,
 360                    typename std::enable_if<std::is_convertible<_Up*,
 361                    pointer>::value>::type* = 0) = delete;
 362
 363       template<typename _Up>
 364         explicit
 365         unique_ptr(_Up*, typename std::enable_if<std::is_convertible<_Up*,
 366                    pointer>::value>::type* = 0) = delete;
 367
 368     private:
 369       __tuple_type _M_t;
 370   };
 371
 372   template<typename _Tp, typename _Tp_Deleter>
 373     inline void
 374     swap(unique_ptr<_Tp, _Tp_Deleter>& __x,
 375          unique_ptr<_Tp, _Tp_Deleter>& __y)
 376     { __x.swap(__y); }
 377
 378   template<typename _Tp, typename _Tp_Deleter,
 379            typename _Up, typename _Up_Deleter>
 380     inline bool
 381     operator==(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 382                const unique_ptr<_Up, _Up_Deleter>& __y)
 383     { return __x.get() == __y.get(); }
 384
 385   template<typename _Tp, typename _Tp_Deleter,
 386            typename _Up, typename _Up_Deleter>
 387     inline bool
 388     operator!=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 389                const unique_ptr<_Up, _Up_Deleter>& __y)
 390     { return !(__x.get() == __y.get()); }
 391
 392   template<typename _Tp, typename _Tp_Deleter,
 393            typename _Up, typename _Up_Deleter>
 394     inline bool
 395     operator<(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 396               const unique_ptr<_Up, _Up_Deleter>& __y)
 397     { return __x.get() < __y.get(); }
 398
 399   template<typename _Tp, typename _Tp_Deleter,
 400            typename _Up, typename _Up_Deleter>
 401     inline bool
 402     operator<=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 403                const unique_ptr<_Up, _Up_Deleter>& __y)
 404     { return !(__y.get() < __x.get()); }
 405
 406   template<typename _Tp, typename _Tp_Deleter,
 407            typename _Up, typename _Up_Deleter>
 408     inline bool
 409     operator>(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 410               const unique_ptr<_Up, _Up_Deleter>& __y)
 411     { return __y.get() < __x.get(); }
 412
 413   template<typename _Tp, typename _Tp_Deleter,
 414            typename _Up, typename _Up_Deleter>
 415     inline bool
 416     operator>=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 417                const unique_ptr<_Up, _Up_Deleter>& __y)
 418     { return !(__x.get() < __y.get()); }
 419
 420   // @} group pointer_abstractions
 421
 422 _GLIBCXX_END_NAMESPACE
 423
 424 #endif /* _UNIQUE_PTR_H */