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

   1 // unique_ptr implementation -*- C++ -*-
   2
   3 // Copyright (C) 2008 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 2, 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 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  19 // Boston, MA 02110-1301, USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /** @file unique_ptr.h
  31  *  This is an internal header file, included by other library headers.
  32  *  You should not attempt to use it directly.
  33  */
  34
  35 #ifndef _UNIQUE_PTR_H
  36 #define _UNIQUE_PTR_H 1
  37
  38 #ifndef __GXX_EXPERIMENTAL_CXX0X__
  39 # include <c++0x_warning.h>
  40 #endif
  41
  42 #include <bits/c++config.h>
  43 #include <debug/debug.h>
  44 #include <type_traits>
  45 #include <utility>
  46 #include <tuple>
  47
  48 _GLIBCXX_BEGIN_NAMESPACE(std)
  49
  50   /// Primary template, default_delete.
  51   template<typename _Tp>
  52     struct default_delete
  53       {
  54         default_delete() { }
  55
  56         template<typename _Up>
  57           default_delete(const default_delete<_Up>&) { }
  58
  59         void
  60         operator()(_Tp* __ptr) const
  61         {
  62           static_assert(sizeof(_Tp)>0,
  63                         "can't delete pointer to incomplete type");
  64           delete __ptr;
  65         }
  66     };
  67
  68   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  69   // DR 740 - omit specialization for array objects with a compile time length
  70   /// Specialization, default_delete.
  71   template<typename _Tp>
  72     struct default_delete<_Tp[]>
  73     {
  74       void
  75       operator()(_Tp* __ptr) const
  76       {
  77         static_assert(sizeof(_Tp)>0,
  78                       "can't delete pointer to incomplete type");
  79         delete [] __ptr;
  80       }
  81     };
  82
  83   /// 20.6.11.2 unique_ptr for single objects.
  84   template <typename _Tp, typename _Tp_Deleter = default_delete<_Tp> >
  85     class unique_ptr
  86     {
  87       typedef _Tp* pointer;
  88       typedef unique_ptr<_Tp, _Tp_Deleter> __this_type;
  89       typedef std::tuple<pointer, _Tp_Deleter> __tuple_type;
  90       typedef __tuple_type __this_type::* __unspecified_bool_type;
  91       typedef pointer __this_type::* __unspecified_pointer_type;
  92
  93     public:
  94       typedef _Tp         element_type;
  95       typedef _Tp_Deleter deleter_type;
  96
  97       // constructors
  98       unique_ptr()
  99       : _M_t(pointer(), deleter_type())
 100       { static_assert(!std::is_pointer<deleter_type>::value,
 101                       "constructed with null function pointer deleter"); }
 102
 103       explicit
 104       unique_ptr(pointer __p)
 105       : _M_t(__p, deleter_type())
 106       { static_assert(!std::is_pointer<deleter_type>::value,
 107                      "constructed with null function pointer deleter"); }
 108
 109       unique_ptr(pointer __p,
 110           typename std::conditional<std::is_reference<deleter_type>::value,
 111             deleter_type, const deleter_type&>::type __d)
 112       : _M_t(__p, __d) { }
 113
 114       unique_ptr(pointer __p,
 115           typename std::remove_reference<deleter_type>::type&& __d)
 116       : _M_t(std::move(__p), std::move(__d))
 117       { static_assert(!std::is_reference<deleter_type>::value,
 118                       "rvalue deleter bound to reference"); }
 119
 120       // move constructors
 121       unique_ptr(unique_ptr && __u)
 122       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 123
 124       template<typename _Up, typename _Up_Deleter>
 125         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 126         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 127         { }
 128
 129       // destructor
 130       ~unique_ptr() { reset(); }
 131
 132       // assignment
 133       unique_ptr&
 134       operator=(unique_ptr&& __u)
 135       {
 136         reset(__u.release());
 137         get_deleter() = std::move(__u.get_deleter());
 138         return *this;
 139       }
 140
 141       template<typename _Up, typename _Up_Deleter>
 142         unique_ptr&
 143         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 144         {
 145           reset(__u.release());
 146           get_deleter() = std::move(__u.get_deleter());
 147           return *this;
 148         }
 149
 150       unique_ptr&
 151       operator=(__unspecified_pointer_type)
 152       {
 153         reset();
 154         return *this;
 155       }
 156
 157       // observers
 158       typename std::add_lvalue_reference<element_type>::type operator*() const
 159       {
 160         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 161         return *get();
 162       }
 163
 164       pointer
 165       operator->() const
 166       {
 167         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 168         return get();
 169       }
 170
 171       pointer
 172       get() const
 173       { return std::get<0>(_M_t); }
 174
 175       typename std::add_lvalue_reference<deleter_type>::type
 176       get_deleter()
 177       { return std::get<1>(_M_t); }
 178
 179       typename std::add_lvalue_reference<
 180           typename std::add_const<deleter_type>::type
 181               >::type
 182       get_deleter() const
 183       { return std::get<1>(_M_t); }
 184
 185       operator __unspecified_bool_type () const
 186       { return get() == 0 ? 0 : &__this_type::_M_t; }
 187
 188       // modifiers
 189       pointer
 190       release()
 191       {
 192         pointer __p = get();
 193         std::get<0>(_M_t) = 0;
 194         return __p;
 195       }
 196
 197       void
 198       reset(pointer __p = 0)
 199       {
 200         if (__p != get())
 201           {
 202             get_deleter()(get());
 203             std::get<0>(_M_t) = __p;
 204           }
 205       }
 206
 207       void
 208       swap(unique_ptr&& __u)
 209       { using std::swap;
 210         swap(_M_t, __u._M_t);
 211       }
 212
 213     private:
 214       // disable copy from lvalue
 215       unique_ptr(const unique_ptr&);
 216
 217       template<typename _Up, typename _Up_Deleter>
 218         unique_ptr(const unique_ptr<_Up, _Up_Deleter>&);
 219
 220       // disable assignment from lvalue
 221       unique_ptr& operator=(const unique_ptr&);
 222
 223       template<typename _Up, typename _Up_Deleter>
 224         unique_ptr& operator=(const unique_ptr<_Up, _Up_Deleter>&);
 225
 226     private:
 227       __tuple_type _M_t;
 228   };
 229
 230   /// 20.6.11.3 unique_ptr for array objects with a runtime length
 231   // [unique.ptr.runtime]
 232   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 233   // DR 740 - omit specialization for array objects with a compile time length
 234   template<typename _Tp, typename _Tp_Deleter>
 235     class unique_ptr<_Tp[], _Tp_Deleter>
 236     {
 237       typedef _Tp* pointer;
 238       typedef unique_ptr<_Tp[], _Tp_Deleter> __this_type;
 239       typedef std::tuple<pointer, _Tp_Deleter> __tuple_type;
 240       typedef __tuple_type __this_type::* __unspecified_bool_type;
 241       typedef pointer __this_type::* __unspecified_pointer_type;
 242     public:
 243       typedef _Tp         element_type;
 244       typedef _Tp_Deleter deleter_type;
 245
 246       // constructors
 247       unique_ptr()
 248       : _M_t(pointer(), deleter_type())
 249       { static_assert(!std::is_pointer<deleter_type>::value,
 250                       "constructed with null function pointer deleter"); }
 251
 252       explicit
 253       unique_ptr(pointer __p)
 254       : _M_t(__p, deleter_type())
 255       { static_assert(!std::is_pointer<deleter_type>::value,
 256                       "constructed with null function pointer deleter"); }
 257
 258       unique_ptr(pointer __p,
 259           typename std::conditional<std::is_reference<deleter_type>::value,
 260               deleter_type, const deleter_type&>::type __d)
 261       : _M_t(__p, __d) { }
 262
 263       unique_ptr(pointer __p,
 264                  typename std::remove_reference<deleter_type>::type && __d)
 265       : _M_t(std::move(__p), std::move(__d))
 266       { static_assert(!std::is_reference<deleter_type>::value,
 267                       "rvalue deleter bound to reference"); }
 268
 269       // move constructors
 270       unique_ptr(unique_ptr&& __u)
 271       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 272
 273       template<typename _Up, typename _Up_Deleter>
 274         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 275         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 276         { }
 277
 278       // destructor
 279       ~unique_ptr() { reset(); }
 280
 281       // assignment
 282       unique_ptr&
 283       operator=(unique_ptr&& __u)
 284       {
 285         reset(__u.release());
 286         get_deleter() = std::move(__u.get_deleter());
 287         return *this;
 288       }
 289
 290       template<typename _Up, typename _Up_Deleter>
 291         unique_ptr&
 292         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 293         {
 294           reset(__u.release());
 295           get_deleter() = std::move(__u.get_deleter());
 296           return *this;
 297         }
 298
 299       unique_ptr&
 300       operator=(__unspecified_pointer_type)
 301       {
 302         reset();
 303         return *this;
 304       }
 305
 306       // observers
 307       typename std::add_lvalue_reference<element_type>::type
 308       operator[](size_t __i) const
 309       {
 310         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 311         return get()[__i];
 312       }
 313
 314       pointer
 315       get() const
 316       { return std::get<0>(_M_t); }
 317
 318       typename std::add_lvalue_reference<deleter_type>::type
 319       get_deleter()
 320       { return std::get<1>(_M_t); }
 321
 322       typename std::add_lvalue_reference<
 323           typename std::add_const<deleter_type>::type
 324               >::type
 325       get_deleter() const
 326       { return std::get<1>(_M_t); }
 327
 328       operator __unspecified_bool_type () const
 329       { return get() == 0 ? 0 : &__this_type::_M_t; }
 330
 331       // modifiers
 332       pointer
 333       release()
 334       {
 335         pointer __p = get();
 336         std::get<0>(_M_t) = 0;
 337         return __p;
 338       }
 339
 340       void
 341       reset(pointer __p = 0)
 342       {
 343         if (__p != get())
 344         {
 345           get_deleter()(get());
 346           std::get<0>(_M_t) = __p;
 347         }
 348       }
 349
 350       void
 351       swap(unique_ptr&& __u)
 352       {
 353         using std::swap;
 354         swap(_M_t, __u._M_t);
 355       }
 356
 357     private:
 358       // disable copy from lvalue
 359       unique_ptr(const unique_ptr&);
 360       unique_ptr& operator=(const unique_ptr&);
 361
 362       // disable construction from convertible pointer types
 363       // (N2315 - 20.6.5.3.1)
 364       template<typename _Up> unique_ptr(_Up*,
 365         typename std::conditional<std::is_reference<deleter_type>::value,
 366           deleter_type, const deleter_type&>::type,
 367             typename std::enable_if<std::is_convertible<_Up*,
 368                 pointer>::value>::type* = 0);
 369
 370       template<typename _Up> unique_ptr(_Up*,
 371         typename std::remove_reference<deleter_type>::type&&,
 372           typename std::enable_if<std::is_convertible<_Up*,
 373               pointer>::value>::type* = 0);
 374
 375       template<typename _Up> explicit unique_ptr(_Up*,
 376         typename std::enable_if<std::is_convertible<_Up*,
 377             pointer>::value>::type* = 0);
 378
 379       // disable reset with convertible pointer types (N2315 - 20.6.5.3.3)
 380       template<typename _Up>
 381         typename std::enable_if<std::is_convertible<_Up*,
 382           pointer>::value>::type reset(_Up*);
 383
 384     private:
 385       __tuple_type _M_t;
 386   };
 387
 388   template<typename _Tp, typename _Tp_Deleter>
 389     inline void
 390     swap(unique_ptr<_Tp, _Tp_Deleter>& __x,
 391          unique_ptr<_Tp, _Tp_Deleter>& __y)
 392     { __x.swap(__y); }
 393
 394   template<typename _Tp, typename _Tp_Deleter>
 395     inline void
 396     swap(unique_ptr<_Tp, _Tp_Deleter>&& __x,
 397          unique_ptr<_Tp, _Tp_Deleter>& __y)
 398     { __x.swap(__y); }
 399
 400   template<typename _Tp, typename _Tp_Deleter>
 401     inline void
 402     swap(unique_ptr<_Tp, _Tp_Deleter>& __x,
 403          unique_ptr<_Tp, _Tp_Deleter>&& __y)
 404     { __x.swap(__y); }
 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 __x.get() == __y.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   template<typename _Tp, typename _Tp_Deleter,
 421            typename _Up, typename _Up_Deleter>
 422     inline bool
 423     operator<(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 424               const unique_ptr<_Up, _Up_Deleter>& __y)
 425     { return __x.get() < __y.get(); }
 426
 427   template<typename _Tp, typename _Tp_Deleter,
 428            typename _Up, typename _Up_Deleter>
 429     inline bool
 430     operator<=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 431                const unique_ptr<_Up, _Up_Deleter>& __y)
 432     { return !(__y.get() < __x.get()); }
 433
 434   template<typename _Tp, typename _Tp_Deleter,
 435            typename _Up, typename _Up_Deleter>
 436     inline bool
 437     operator>(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 438               const unique_ptr<_Up, _Up_Deleter>& __y)
 439     { return __y.get() < __x.get(); }
 440
 441   template<typename _Tp, typename _Tp_Deleter,
 442            typename _Up, typename _Up_Deleter>
 443     inline bool
 444     operator>=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 445                const unique_ptr<_Up, _Up_Deleter>& __y)
 446     { return !(__x.get() < __y.get()); }
 447
 448 _GLIBCXX_END_NAMESPACE
 449
 450 #endif /* _UNIQUE_PTR_H */