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

   1 // unique_ptr implementation -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009, 2010, 2011 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/unique_ptr.h
  26  *  This is an internal header file, included by other library headers.
  27  *  Do not attempt to use it directly. @headername{memory}
  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 namespace std _GLIBCXX_VISIBILITY(default)
  40 {
  41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  42
  43   /**
  44    * @addtogroup pointer_abstractions
  45    * @{
  46    */
  47
  48   /// Primary template, default_delete.
  49   template<typename _Tp>
  50     struct default_delete
  51     {
  52       constexpr default_delete() = default;
  53
  54       template<typename _Up, typename = typename
  55                std::enable_if<std::is_convertible<_Up*, _Tp*>::value>::type>
  56         default_delete(const default_delete<_Up>&) { }
  57
  58       void
  59       operator()(_Tp* __ptr) const
  60       {
  61         static_assert(sizeof(_Tp)>0,
  62                       "can't delete pointer to incomplete type");
  63         delete __ptr;
  64       }
  65     };
  66
  67   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  68   // DR 740 - omit specialization for array objects with a compile time length
  69   /// Specialization, default_delete.
  70   template<typename _Tp>
  71     struct default_delete<_Tp[]>
  72     {
  73       constexpr default_delete() = default;
  74
  75       void
  76       operator()(_Tp* __ptr) const
  77       {
  78         static_assert(sizeof(_Tp)>0,
  79                       "can't delete pointer to incomplete type");
  80         delete [] __ptr;
  81       }
  82     };
  83
  84   /// 20.7.12.2 unique_ptr for single objects.
  85   template <typename _Tp, typename _Dp = default_delete<_Tp> >
  86     class unique_ptr
  87     {
  88       // use SFINAE to determine whether _Del::pointer exists
  89       class _Pointer
  90       {
  91         template<typename _Up>
  92           static typename _Up::pointer __test(typename _Up::pointer*);
  93
  94         template<typename _Up>
  95           static _Tp* __test(...);
  96
  97         typedef typename remove_reference<_Dp>::type _Del;
  98
  99       public:
 100         typedef decltype( __test<_Del>(0)) type;
 101       };
 102
 103       typedef std::tuple<_Tp*, _Dp>     __tuple_type;
 104       __tuple_type                      _M_t;
 105
 106     public:
 107       typedef typename _Pointer::type   pointer;
 108       typedef _Tp                       element_type;
 109       typedef _Dp                       deleter_type;
 110
 111       // Constructors.
 112       constexpr unique_ptr()
 113       : _M_t()
 114       { static_assert(!std::is_pointer<deleter_type>::value,
 115                      "constructed with null function pointer deleter"); }
 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()
 136       { static_assert(!std::is_pointer<deleter_type>::value,
 137                      "constructed with null function pointer deleter"); }
 138
 139       // Move constructors.
 140       unique_ptr(unique_ptr&& __u)
 141       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 142
 143       template<typename _Up, typename _Ep, typename = typename
 144         std::enable_if
 145           <std::is_convertible<typename unique_ptr<_Up, _Ep>::pointer,
 146                                pointer>::value
 147            && !std::is_array<_Up>::value
 148            && ((std::is_reference<_Dp>::value
 149                 && std::is_same<_Ep, _Dp>::value)
 150                || (!std::is_reference<_Dp>::value
 151                    && std::is_convertible<_Ep, _Dp>::value))>
 152              ::type>
 153         unique_ptr(unique_ptr<_Up, _Ep>&& __u)
 154         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 155         { }
 156
 157 #if _GLIBCXX_USE_DEPRECATED
 158       template<typename _Up, typename = typename
 159         std::enable_if<std::is_convertible<_Up*, _Tp*>::value
 160                        && std::is_same<_Dp,
 161                                        default_delete<_Tp>>::value>::type>
 162         unique_ptr(auto_ptr<_Up>&& __u)
 163         : _M_t(__u.release(), deleter_type()) { }
 164 #endif
 165
 166       // Destructor.
 167       ~unique_ptr() { reset(); }
 168
 169       // Assignment.
 170       unique_ptr&
 171       operator=(unique_ptr&& __u)
 172       {
 173         reset(__u.release());
 174         get_deleter() = std::move(__u.get_deleter());
 175         return *this;
 176       }
 177
 178       template<typename _Up, typename _Ep, typename = typename
 179         std::enable_if
 180           <std::is_convertible<typename unique_ptr<_Up, _Ep>::pointer,
 181                                pointer>::value
 182            && !std::is_array<_Up>::value>::type>
 183         unique_ptr&
 184         operator=(unique_ptr<_Up, _Ep>&& __u)
 185         {
 186           reset(__u.release());
 187           get_deleter() = std::move(__u.get_deleter());
 188           return *this;
 189         }
 190
 191       unique_ptr&
 192       operator=(nullptr_t)
 193       {
 194         reset();
 195         return *this;
 196       }
 197
 198       // Observers.
 199       typename std::add_lvalue_reference<element_type>::type
 200       operator*() const
 201       {
 202         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 203         return *get();
 204       }
 205
 206       pointer
 207       operator->() const
 208       {
 209         _GLIBCXX_DEBUG_ASSERT(get() != pointer());
 210         return get();
 211       }
 212
 213       pointer
 214       get() const
 215       { return std::get<0>(_M_t); }
 216
 217       deleter_type&
 218       get_deleter()
 219       { return std::get<1>(_M_t); }
 220
 221       const deleter_type&
 222       get_deleter() const
 223       { return std::get<1>(_M_t); }
 224
 225       explicit operator bool() const
 226       { return get() == pointer() ? false : true; }
 227
 228       // Modifiers.
 229       pointer
 230       release()
 231       {
 232         pointer __p = get();
 233         std::get<0>(_M_t) = pointer();
 234         return __p;
 235       }
 236
 237       void
 238       reset(pointer __p = pointer())
 239       {
 240         using std::swap;
 241         swap(std::get<0>(_M_t), __p);
 242         if (__p != pointer())
 243           get_deleter()(__p);
 244       }
 245
 246       void
 247       swap(unique_ptr& __u)
 248       {
 249         using std::swap;
 250         swap(_M_t, __u._M_t);
 251       }
 252
 253       // Disable copy from lvalue.
 254       unique_ptr(const unique_ptr&) = delete;
 255       unique_ptr& operator=(const unique_ptr&) = delete;
 256   };
 257
 258   /// 20.7.12.3 unique_ptr for array objects with a runtime length
 259   // [unique.ptr.runtime]
 260   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 261   // DR 740 - omit specialization for array objects with a compile time length
 262   template<typename _Tp, typename _Dp>
 263     class unique_ptr<_Tp[], _Dp>
 264     {
 265       typedef std::tuple<_Tp*, _Dp>     __tuple_type;
 266       __tuple_type                      _M_t;
 267
 268     public:
 269       typedef _Tp*                      pointer;
 270       typedef _Tp                       element_type;
 271       typedef _Dp                       deleter_type;
 272
 273       // Constructors.
 274       constexpr unique_ptr()
 275       : _M_t()
 276       { static_assert(!std::is_pointer<deleter_type>::value,
 277                      "constructed with null function pointer deleter"); }
 278
 279       explicit
 280       unique_ptr(pointer __p)
 281       : _M_t(__p, deleter_type())
 282       { static_assert(!std::is_pointer<deleter_type>::value,
 283                      "constructed with null function pointer deleter"); }
 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       constexpr unique_ptr(nullptr_t)
 297       : _M_t()
 298       { static_assert(!std::is_pointer<deleter_type>::value,
 299                      "constructed with null function pointer deleter"); }
 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_VERSION
 507 } // namespace
 508
 509 #endif /* _UNIQUE_PTR_H */