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       constexpr default_delete() { }
  51
  52       template<typename _Up, typename = typename
  53                std::enable_if<std::is_convertible<_Up*, _Tp*>::value>::type>
  54         default_delete(const default_delete<_Up>&) { }
  55
  56       void
  57       operator()(_Tp* __ptr) const
  58       {
  59         static_assert(sizeof(_Tp)>0,
  60                       "can't delete pointer to incomplete type");
  61         delete __ptr;
  62       }
  63     };
  64
  65   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  66   // DR 740 - omit specialization for array objects with a compile time length
  67   /// Specialization, default_delete.
  68   template<typename _Tp>
  69     struct default_delete<_Tp[]>
  70     {
  71       constexpr default_delete() { }
  72
  73       void
  74       operator()(_Tp* __ptr) const
  75       {
  76         static_assert(sizeof(_Tp)>0,
  77                       "can't delete pointer to incomplete type");
  78         delete [] __ptr;
  79       }
  80     };
  81
  82   /// 20.7.12.2 unique_ptr for single objects.
  83   template <typename _Tp, typename _Dp = default_delete<_Tp> >
  84     class unique_ptr
  85     {
  86       // use SFINAE to determine whether _Del::pointer exists
  87       class _Pointer
  88       {
  89         template<typename _Up>
  90           static typename _Up::pointer __test(typename _Up::pointer*);
  91
  92         template<typename _Up>
  93           static _Tp* __test(...);
  94
  95         typedef typename remove_reference<_Dp>::type _Del;
  96
  97       public:
  98         typedef decltype( __test<_Del>(0)) type;
  99       };
 100
 101       typedef std::tuple<_Tp*, _Dp>     __tuple_type;
 102       __tuple_type                      _M_t;
 103
 104     public:
 105       typedef typename _Pointer::type   pointer;
 106       typedef _Tp                       element_type;
 107       typedef _Dp                       deleter_type;
 108
 109       static_assert(!std::is_pointer<deleter_type>::value,
 110                     "constructed with null function pointer deleter");
 111
 112       // Constructors.
 113       constexpr unique_ptr()
 114       : _M_t()
 115       { }
 116
 117       explicit
 118       unique_ptr(pointer __p)
 119       : _M_t(__p, deleter_type())
 120       { static_assert(!std::is_pointer<deleter_type>::value,
 121                      "constructed with null function pointer deleter"); }
 122
 123       unique_ptr(pointer __p,
 124           typename std::conditional<std::is_reference<deleter_type>::value,
 125             deleter_type, const deleter_type&>::type __d)
 126       : _M_t(__p, __d) { }
 127
 128       unique_ptr(pointer __p,
 129           typename std::remove_reference<deleter_type>::type&& __d)
 130       : _M_t(std::move(__p), std::move(__d))
 131       { static_assert(!std::is_reference<deleter_type>::value,
 132                       "rvalue deleter bound to reference"); }
 133
 134       constexpr unique_ptr(nullptr_t)
 135       : _M_t(pointer(), deleter_type())
 136       { }
 137
 138       // Move constructors.
 139       unique_ptr(unique_ptr&& __u)
 140       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 141
 142       template<typename _Up, typename _Ep, typename = typename
 143         std::enable_if
 144           <std::is_convertible<typename unique_ptr<_Up, _Ep>::pointer,
 145                                pointer>::value
 146            && !std::is_array<_Up>::value
 147            && ((std::is_reference<_Dp>::value
 148                 && std::is_same<_Ep, _Dp>::value)
 149                || (!std::is_reference<_Dp>::value
 150                    && std::is_convertible<_Ep, _Dp>::value))>
 151              ::type>
 152         unique_ptr(unique_ptr<_Up, _Ep>&& __u)
 153         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 154         { }
 155
 156 #if _GLIBCXX_DEPRECATED
 157       template<typename _Up, typename = typename
 158         std::enable_if<std::is_convertible<_Up*, _Tp*>::value
 159                        && std::is_same<_Dp,
 160                                        default_delete<_Tp>>::value>::type>
 161         unique_ptr(auto_ptr<_Up>&& __u)
 162         : _M_t(__u.release(), deleter_type()) { }
 163 #endif
 164
 165       // Destructor.
 166       ~unique_ptr() { reset(); }
 167
 168       // Assignment.
 169       unique_ptr&
 170       operator=(unique_ptr&& __u)
 171       {
 172         reset(__u.release());
 173         get_deleter() = std::move(__u.get_deleter());
 174         return *this;
 175       }
 176
 177       template<typename _Up, typename _Ep, typename = typename
 178         std::enable_if
 179           <std::is_convertible<typename unique_ptr<_Up, _Ep>::pointer,
 180                                pointer>::value
 181            && !std::is_array<_Up>::value>::type>
 182         unique_ptr&
 183         operator=(unique_ptr<_Up, _Ep>&& __u)
 184         {
 185           reset(__u.release());
 186           get_deleter() = std::move(__u.get_deleter());
 187           return *this;
 188         }
 189
 190       unique_ptr&
 191       operator=(nullptr_t)
 192       {
 193         reset();
 194         return *this;
 195       }
 196
 197       // Observers.
 198       typename std::add_lvalue_reference<element_type>::type
 199       operator*() const
 200       {
 201         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 202         return *get();
 203       }
 204
 205       pointer
 206       operator->() const
 207       {
 208         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 209         return get();
 210       }
 211
 212       pointer
 213       get() const
 214       { return std::get<0>(_M_t); }
 215
 216       deleter_type&
 217       get_deleter()
 218       { return std::get<1>(_M_t); }
 219
 220       const deleter_type&
 221       get_deleter() const
 222       { return std::get<1>(_M_t); }
 223
 224       explicit operator bool() const
 225       { return get() == pointer() ? false : true; }
 226
 227       // Modifiers.
 228       pointer
 229       release()
 230       {
 231         pointer __p = get();
 232         std::get<0>(_M_t) = pointer();
 233         return __p;
 234       }
 235
 236       void
 237       reset(pointer __p = pointer())
 238       {
 239         using std::swap;
 240         swap(std::get<0>(_M_t), __p);
 241         if (__p != pointer())
 242           get_deleter()(__p);
 243       }
 244
 245       void
 246       swap(unique_ptr& __u)
 247       {
 248         using std::swap;
 249         swap(_M_t, __u._M_t);
 250       }
 251
 252       // Disable copy from lvalue.
 253       unique_ptr(const unique_ptr&) = delete;
 254       unique_ptr& operator=(const unique_ptr&) = delete;
 255   };
 256
 257   /// 20.7.12.3 unique_ptr for array objects with a runtime length
 258   // [unique.ptr.runtime]
 259   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 260   // DR 740 - omit specialization for array objects with a compile time length
 261   template<typename _Tp, typename _Dp>
 262     class unique_ptr<_Tp[], _Dp>
 263     {
 264       typedef std::tuple<_Tp*, _Dp>     __tuple_type;
 265       __tuple_type                      _M_t;
 266
 267     public:
 268       typedef _Tp*                      pointer;
 269       typedef _Tp                       element_type;
 270       typedef _Dp                       deleter_type;
 271
 272       static_assert(!std::is_pointer<deleter_type>::value,
 273                     "constructed with null function pointer deleter");
 274
 275       // Constructors.
 276       constexpr unique_ptr()
 277       : _M_t(pointer(), deleter_type())
 278       { }
 279
 280       explicit
 281       unique_ptr(pointer __p)
 282       : _M_t(__p, deleter_type())
 283       { }
 284
 285       unique_ptr(pointer __p,
 286           typename std::conditional<std::is_reference<deleter_type>::value,
 287               deleter_type, const deleter_type&>::type __d)
 288       : _M_t(__p, __d) { }
 289
 290       unique_ptr(pointer __p,
 291                  typename std::remove_reference<deleter_type>::type && __d)
 292       : _M_t(std::move(__p), std::move(__d))
 293       { static_assert(!std::is_reference<deleter_type>::value,
 294                       "rvalue deleter bound to reference"); }
 295
 296       /* TODO: use delegating constructor */
 297       constexpr unique_ptr(nullptr_t)
 298       : _M_t(pointer(), deleter_type())
 299       { }
 300
 301       // Move constructors.
 302       unique_ptr(unique_ptr&& __u)
 303       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 304
 305       template<typename _Up, typename _Ep>
 306         unique_ptr(unique_ptr<_Up, _Ep>&& __u)
 307         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 308         { }
 309
 310       // Destructor.
 311       ~unique_ptr() { reset(); }
 312
 313       // Assignment.
 314       unique_ptr&
 315       operator=(unique_ptr&& __u)
 316       {
 317         reset(__u.release());
 318         get_deleter() = std::move(__u.get_deleter());
 319         return *this;
 320       }
 321
 322       template<typename _Up, typename _Ep>
 323         unique_ptr&
 324         operator=(unique_ptr<_Up, _Ep>&& __u)
 325         {
 326           reset(__u.release());
 327           get_deleter() = std::move(__u.get_deleter());
 328           return *this;
 329         }
 330
 331       unique_ptr&
 332       operator=(nullptr_t)
 333       {
 334         reset();
 335         return *this;
 336       }
 337
 338       // Observers.
 339       typename std::add_lvalue_reference<element_type>::type
 340       operator[](size_t __i) const
 341       {
 342         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 343         return get()[__i];
 344       }
 345
 346       pointer
 347       get() const
 348       { return std::get<0>(_M_t); }
 349
 350       deleter_type&
 351       get_deleter()
 352       { return std::get<1>(_M_t); }
 353
 354       const deleter_type&
 355       get_deleter() const
 356       { return std::get<1>(_M_t); }
 357
 358       explicit operator bool() const
 359       { return get() == pointer() ? false : true; }
 360
 361       // Modifiers.
 362       pointer
 363       release()
 364       {
 365         pointer __p = get();
 366         std::get<0>(_M_t) = pointer();
 367         return __p;
 368       }
 369
 370       void
 371       reset(pointer __p = pointer())
 372       {
 373         using std::swap;
 374         swap(std::get<0>(_M_t), __p);
 375         if (__p != nullptr)
 376           get_deleter()(__p);
 377       }
 378
 379       void
 380       reset(nullptr_t)
 381       {
 382         pointer __p = get();
 383         std::get<0>(_M_t) = pointer();
 384         if (__p != nullptr)
 385           get_deleter()(__p);
 386       }
 387
 388       // DR 821.
 389       template<typename _Up>
 390         void reset(_Up) = delete;
 391
 392       void
 393       swap(unique_ptr& __u)
 394       {
 395         using std::swap;
 396         swap(_M_t, __u._M_t);
 397       }
 398
 399       // Disable copy from lvalue.
 400       unique_ptr(const unique_ptr&) = delete;
 401       unique_ptr& operator=(const unique_ptr&) = delete;
 402
 403       // Disable construction from convertible pointer types.
 404       // (N2315 - 20.6.5.3.1)
 405       template<typename _Up>
 406         unique_ptr(_Up*, typename
 407                    std::conditional<std::is_reference<deleter_type>::value,
 408                    deleter_type, const deleter_type&>::type,
 409                    typename std::enable_if<std::is_convertible<_Up*,
 410                    pointer>::value>::type* = 0) = delete;
 411
 412       template<typename _Up>
 413         unique_ptr(_Up*, typename std::remove_reference<deleter_type>::type&&,
 414                    typename std::enable_if<std::is_convertible<_Up*,
 415                    pointer>::value>::type* = 0) = delete;
 416
 417       template<typename _Up>
 418         explicit
 419         unique_ptr(_Up*, typename std::enable_if<std::is_convertible<_Up*,
 420                    pointer>::value>::type* = 0) = delete;
 421   };
 422
 423   template<typename _Tp, typename _Dp>
 424     inline void
 425     swap(unique_ptr<_Tp, _Dp>& __x,
 426          unique_ptr<_Tp, _Dp>& __y)
 427     { __x.swap(__y); }
 428
 429   template<typename _Tp, typename _Dp,
 430            typename _Up, typename _Ep>
 431     inline bool
 432     operator==(const unique_ptr<_Tp, _Dp>& __x,
 433                const unique_ptr<_Up, _Ep>& __y)
 434     { return __x.get() == __y.get(); }
 435
 436   template<typename _Tp, typename _Dp>
 437     inline bool
 438     operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
 439     { return __x.get() == nullptr; }
 440
 441   template<typename _Tp, typename _Dp>
 442     inline bool
 443     operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __y)
 444     { return nullptr == __y.get(); }
 445
 446   template<typename _Tp, typename _Dp,
 447            typename _Up, typename _Ep>
 448     inline bool
 449     operator!=(const unique_ptr<_Tp, _Dp>& __x,
 450                const unique_ptr<_Up, _Ep>& __y)
 451     { return !(__x.get() == __y.get()); }
 452
 453   template<typename _Tp, typename _Dp>
 454     inline bool
 455     operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
 456     { return __x.get() != nullptr; }
 457
 458   template<typename _Tp, typename _Dp>
 459     inline bool
 460     operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __y)
 461     { return nullptr != __y.get(); }
 462
 463   template<typename _Tp, typename _Dp,
 464            typename _Up, typename _Ep>
 465     inline bool
 466     operator<(const unique_ptr<_Tp, _Dp>& __x,
 467               const unique_ptr<_Up, _Ep>& __y)
 468     { return __x.get() < __y.get(); }
 469
 470   template<typename _Tp, typename _Dp,
 471            typename _Up, typename _Ep>
 472     inline bool
 473     operator<=(const unique_ptr<_Tp, _Dp>& __x,
 474                const unique_ptr<_Up, _Ep>& __y)
 475     { return !(__y.get() < __x.get()); }
 476
 477   template<typename _Tp, typename _Dp,
 478            typename _Up, typename _Ep>
 479     inline bool
 480     operator>(const unique_ptr<_Tp, _Dp>& __x,
 481               const unique_ptr<_Up, _Ep>& __y)
 482     { return __y.get() < __x.get(); }
 483
 484   template<typename _Tp, typename _Dp,
 485            typename _Up, typename _Ep>
 486     inline bool
 487     operator>=(const unique_ptr<_Tp, _Dp>& __x,
 488                const unique_ptr<_Up, _Ep>& __y)
 489     { return !(__x.get() < __y.get()); }
 490
 491   /// std::hash specialization for unique_ptr.
 492   template<typename _Tp, typename _Dp>
 493     struct hash<unique_ptr<_Tp, _Dp>>
 494     : public std::unary_function<unique_ptr<_Tp, _Dp>, size_t>
 495     {
 496       size_t
 497       operator()(const unique_ptr<_Tp, _Dp>& __u) const
 498       {
 499         typedef unique_ptr<_Tp, _Dp> _UP;
 500         return std::hash<typename _UP::pointer>()(__u.get());
 501       }
 502     };
 503
 504   // @} group pointer_abstractions
 505
 506 _GLIBCXX_END_NAMESPACE
 507
 508 #endif /* _UNIQUE_PTR_H */