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

   1 // unique_ptr implementation -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009 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   /**
  51    * @addtogroup pointer_abstractions
  52    * @{
  53    */
  54
  55   /// Primary template, default_delete.
  56   template<typename _Tp>
  57     struct default_delete
  58       {
  59         default_delete() { }
  60
  61         template<typename _Up>
  62           default_delete(const default_delete<_Up>&) { }
  63
  64         void
  65         operator()(_Tp* __ptr) const
  66         {
  67           static_assert(sizeof(_Tp)>0,
  68                         "can't delete pointer to incomplete type");
  69           delete __ptr;
  70         }
  71     };
  72
  73   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  74   // DR 740 - omit specialization for array objects with a compile time length
  75   /// Specialization, default_delete.
  76   template<typename _Tp>
  77     struct default_delete<_Tp[]>
  78     {
  79       void
  80       operator()(_Tp* __ptr) const
  81       {
  82         static_assert(sizeof(_Tp)>0,
  83                       "can't delete pointer to incomplete type");
  84         delete [] __ptr;
  85       }
  86     };
  87
  88   /// 20.7.12.2 unique_ptr for single objects.
  89   template <typename _Tp, typename _Tp_Deleter = default_delete<_Tp> >
  90     class unique_ptr
  91     {
  92       typedef std::tuple<_Tp*, _Tp_Deleter>  __tuple_type;
  93       typedef __tuple_type unique_ptr::*     __unspecified_bool_type;
  94       typedef _Tp* unique_ptr::*             __unspecified_pointer_type;
  95
  96     public:
  97       typedef _Tp*               pointer;
  98       typedef _Tp                element_type;
  99       typedef _Tp_Deleter        deleter_type;
 100
 101       // Constructors.
 102       unique_ptr()
 103       : _M_t(pointer(), deleter_type())
 104       { static_assert(!std::is_pointer<deleter_type>::value,
 105                       "constructed with null function pointer deleter"); }
 106
 107       explicit
 108       unique_ptr(pointer __p)
 109       : _M_t(__p, deleter_type())
 110       { static_assert(!std::is_pointer<deleter_type>::value,
 111                      "constructed with null function pointer deleter"); }
 112
 113       unique_ptr(pointer __p,
 114           typename std::conditional<std::is_reference<deleter_type>::value,
 115             deleter_type, const deleter_type&>::type __d)
 116       : _M_t(__p, __d) { }
 117
 118       unique_ptr(pointer __p,
 119           typename std::remove_reference<deleter_type>::type&& __d)
 120       : _M_t(std::move(__p), std::move(__d))
 121       { static_assert(!std::is_reference<deleter_type>::value,
 122                       "rvalue deleter bound to reference"); }
 123
 124       // Move constructors.
 125       unique_ptr(unique_ptr&& __u)
 126       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 127
 128       template<typename _Up, typename _Up_Deleter>
 129         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 130         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 131         { }
 132
 133       // Destructor.
 134       ~unique_ptr() { reset(); }
 135
 136       // Assignment.
 137       unique_ptr&
 138       operator=(unique_ptr&& __u)
 139       {
 140         reset(__u.release());
 141         get_deleter() = std::move(__u.get_deleter());
 142         return *this;
 143       }
 144
 145       template<typename _Up, typename _Up_Deleter>
 146         unique_ptr&
 147         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 148         {
 149           reset(__u.release());
 150           get_deleter() = std::move(__u.get_deleter());
 151           return *this;
 152         }
 153
 154       unique_ptr&
 155       operator=(__unspecified_pointer_type)
 156       {
 157         reset();
 158         return *this;
 159       }
 160
 161       // Observers.
 162       typename std::add_lvalue_reference<element_type>::type operator*() const
 163       {
 164         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 165         return *get();
 166       }
 167
 168       pointer
 169       operator->() const
 170       {
 171         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 172         return get();
 173       }
 174
 175       pointer
 176       get() const
 177       { return std::get<0>(_M_t); }
 178
 179       typename std::add_lvalue_reference<deleter_type>::type
 180       get_deleter()
 181       { return std::get<1>(_M_t); }
 182
 183       typename std::add_lvalue_reference<
 184           typename std::add_const<deleter_type>::type
 185               >::type
 186       get_deleter() const
 187       { return std::get<1>(_M_t); }
 188
 189       operator __unspecified_bool_type () const
 190       { return get() == 0 ? 0 : &unique_ptr::_M_t; }
 191
 192       // Modifiers.
 193       pointer
 194       release()
 195       {
 196         pointer __p = get();
 197         std::get<0>(_M_t) = 0;
 198         return __p;
 199       }
 200
 201       void
 202       reset(pointer __p = pointer())
 203       {
 204         if (__p != get())
 205           {
 206             get_deleter()(get());
 207             std::get<0>(_M_t) = __p;
 208           }
 209       }
 210
 211       void
 212       swap(unique_ptr&& __u)
 213       {
 214         using std::swap;
 215         swap(_M_t, __u._M_t);
 216       }
 217
 218       // Disable copy from lvalue.
 219       unique_ptr(const unique_ptr&) = delete;
 220
 221       template<typename _Up, typename _Up_Deleter>
 222         unique_ptr(const unique_ptr<_Up, _Up_Deleter>&) = delete;
 223
 224       unique_ptr& operator=(const unique_ptr&) = delete;
 225
 226       template<typename _Up, typename _Up_Deleter>
 227         unique_ptr& operator=(const unique_ptr<_Up, _Up_Deleter>&) = delete;
 228
 229     private:
 230       __tuple_type _M_t;
 231   };
 232
 233   /// 20.7.12.3 unique_ptr for array objects with a runtime length
 234   // [unique.ptr.runtime]
 235   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 236   // DR 740 - omit specialization for array objects with a compile time length
 237   template<typename _Tp, typename _Tp_Deleter>
 238     class unique_ptr<_Tp[], _Tp_Deleter>
 239     {
 240       typedef std::tuple<_Tp*, _Tp_Deleter>  __tuple_type;
 241       typedef __tuple_type unique_ptr::*     __unspecified_bool_type;
 242       typedef _Tp* unique_ptr::*             __unspecified_pointer_type;
 243
 244     public:
 245       typedef _Tp*               pointer;
 246       typedef _Tp                element_type;
 247       typedef _Tp_Deleter        deleter_type;
 248
 249       // Constructors.
 250       unique_ptr()
 251       : _M_t(pointer(), deleter_type())
 252       { static_assert(!std::is_pointer<deleter_type>::value,
 253                       "constructed with null function pointer deleter"); }
 254
 255       explicit
 256       unique_ptr(pointer __p)
 257       : _M_t(__p, deleter_type())
 258       { static_assert(!std::is_pointer<deleter_type>::value,
 259                       "constructed with null function pointer deleter"); }
 260
 261       unique_ptr(pointer __p,
 262           typename std::conditional<std::is_reference<deleter_type>::value,
 263               deleter_type, const deleter_type&>::type __d)
 264       : _M_t(__p, __d) { }
 265
 266       unique_ptr(pointer __p,
 267                  typename std::remove_reference<deleter_type>::type && __d)
 268       : _M_t(std::move(__p), std::move(__d))
 269       { static_assert(!std::is_reference<deleter_type>::value,
 270                       "rvalue deleter bound to reference"); }
 271
 272       // Move constructors.
 273       unique_ptr(unique_ptr&& __u)
 274       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 275
 276       template<typename _Up, typename _Up_Deleter>
 277         unique_ptr(unique_ptr<_Up, _Up_Deleter>&& __u)
 278         : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter()))
 279         { }
 280
 281       // Destructor.
 282       ~unique_ptr() { reset(); }
 283
 284       // Assignment.
 285       unique_ptr&
 286       operator=(unique_ptr&& __u)
 287       {
 288         reset(__u.release());
 289         get_deleter() = std::move(__u.get_deleter());
 290         return *this;
 291       }
 292
 293       template<typename _Up, typename _Up_Deleter>
 294         unique_ptr&
 295         operator=(unique_ptr<_Up, _Up_Deleter>&& __u)
 296         {
 297           reset(__u.release());
 298           get_deleter() = std::move(__u.get_deleter());
 299           return *this;
 300         }
 301
 302       unique_ptr&
 303       operator=(__unspecified_pointer_type)
 304       {
 305         reset();
 306         return *this;
 307       }
 308
 309       // Observers.
 310       typename std::add_lvalue_reference<element_type>::type
 311       operator[](size_t __i) const
 312       {
 313         _GLIBCXX_DEBUG_ASSERT(get() != 0);
 314         return get()[__i];
 315       }
 316
 317       pointer
 318       get() const
 319       { return std::get<0>(_M_t); }
 320
 321       typename std::add_lvalue_reference<deleter_type>::type
 322       get_deleter()
 323       { return std::get<1>(_M_t); }
 324
 325       typename std::add_lvalue_reference<
 326           typename std::add_const<deleter_type>::type
 327               >::type
 328       get_deleter() const
 329       { return std::get<1>(_M_t); }
 330
 331       operator __unspecified_bool_type () const
 332       { return get() == 0 ? 0 : &unique_ptr::_M_t; }
 333
 334       // Modifiers.
 335       pointer
 336       release()
 337       {
 338         pointer __p = get();
 339         std::get<0>(_M_t) = 0;
 340         return __p;
 341       }
 342
 343       void
 344       reset(pointer __p = pointer())
 345       {
 346         if (__p != get())
 347         {
 348           get_deleter()(get());
 349           std::get<0>(_M_t) = __p;
 350         }
 351       }
 352
 353       // DR 821.
 354       template<typename _Up>
 355         void reset(_Up) = delete;
 356
 357       void
 358       swap(unique_ptr&& __u)
 359       {
 360         using std::swap;
 361         swap(_M_t, __u._M_t);
 362       }
 363
 364       // Disable copy from lvalue.
 365       unique_ptr(const unique_ptr&) = delete;
 366       unique_ptr& operator=(const unique_ptr&) = delete;
 367
 368       // Disable construction from convertible pointer types.
 369       // (N2315 - 20.6.5.3.1)
 370       template<typename _Up>
 371         unique_ptr(_Up*, typename
 372                    std::conditional<std::is_reference<deleter_type>::value,
 373                    deleter_type, const deleter_type&>::type,
 374                    typename std::enable_if<std::is_convertible<_Up*,
 375                    pointer>::value>::type* = 0) = delete;
 376
 377       template<typename _Up>
 378         unique_ptr(_Up*, typename std::remove_reference<deleter_type>::type&&,
 379                    typename std::enable_if<std::is_convertible<_Up*,
 380                    pointer>::value>::type* = 0) = delete;
 381
 382       template<typename _Up>
 383         explicit
 384         unique_ptr(_Up*, typename std::enable_if<std::is_convertible<_Up*,
 385                    pointer>::value>::type* = 0) = delete;
 386
 387     private:
 388       __tuple_type _M_t;
 389   };
 390
 391   template<typename _Tp, typename _Tp_Deleter>
 392     inline void
 393     swap(unique_ptr<_Tp, _Tp_Deleter>& __x,
 394          unique_ptr<_Tp, _Tp_Deleter>& __y)
 395     { __x.swap(__y); }
 396
 397   template<typename _Tp, typename _Tp_Deleter>
 398     inline void
 399     swap(unique_ptr<_Tp, _Tp_Deleter>&& __x,
 400          unique_ptr<_Tp, _Tp_Deleter>& __y)
 401     { __x.swap(__y); }
 402
 403   template<typename _Tp, typename _Tp_Deleter>
 404     inline void
 405     swap(unique_ptr<_Tp, _Tp_Deleter>& __x,
 406          unique_ptr<_Tp, _Tp_Deleter>&& __y)
 407     { __x.swap(__y); }
 408
 409   template<typename _Tp, typename _Tp_Deleter,
 410            typename _Up, typename _Up_Deleter>
 411     inline bool
 412     operator==(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 413                const unique_ptr<_Up, _Up_Deleter>& __y)
 414     { return __x.get() == __y.get(); }
 415
 416   template<typename _Tp, typename _Tp_Deleter,
 417            typename _Up, typename _Up_Deleter>
 418     inline bool
 419     operator!=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 420                const unique_ptr<_Up, _Up_Deleter>& __y)
 421     { return !(__x.get() == __y.get()); }
 422
 423   template<typename _Tp, typename _Tp_Deleter,
 424            typename _Up, typename _Up_Deleter>
 425     inline bool
 426     operator<(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 427               const unique_ptr<_Up, _Up_Deleter>& __y)
 428     { return __x.get() < __y.get(); }
 429
 430   template<typename _Tp, typename _Tp_Deleter,
 431            typename _Up, typename _Up_Deleter>
 432     inline bool
 433     operator<=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 434                const unique_ptr<_Up, _Up_Deleter>& __y)
 435     { return !(__y.get() < __x.get()); }
 436
 437   template<typename _Tp, typename _Tp_Deleter,
 438            typename _Up, typename _Up_Deleter>
 439     inline bool
 440     operator>(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 441               const unique_ptr<_Up, _Up_Deleter>& __y)
 442     { return __y.get() < __x.get(); }
 443
 444   template<typename _Tp, typename _Tp_Deleter,
 445            typename _Up, typename _Up_Deleter>
 446     inline bool
 447     operator>=(const unique_ptr<_Tp, _Tp_Deleter>& __x,
 448                const unique_ptr<_Up, _Up_Deleter>& __y)
 449     { return !(__x.get() < __y.get()); }
 450
 451   // @} group pointer_abstractions
 452
 453 _GLIBCXX_END_NAMESPACE
 454
 455 #endif /* _UNIQUE_PTR_H */