1 // shared_ptr and weak_ptr implementation -*- C++ -*-
3 // Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
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)
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.
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.
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/>.
25 // GCC Note: Based on files from version 1.32.0 of the Boost library.
28 // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
31 // Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
32 // Copyright (C) 2001, 2002, 2003 Peter Dimov
35 // Copyright (C) 2001, 2002, 2003 Peter Dimov
37 // enable_shared_from_this.hpp
38 // Copyright (C) 2002 Peter Dimov
40 // Distributed under the Boost Software License, Version 1.0. (See
41 // accompanying file LICENSE_1_0.txt or copy at
42 // http://www.boost.org/LICENSE_1_0.txt)
44 /** @file bits/shared_ptr.h
45 * This is an internal header file, included by other library headers.
46 * You should not attempt to use it directly.
50 #define _SHARED_PTR_H 1
52 #include <bits/shared_ptr_base.h>
54 _GLIBCXX_BEGIN_NAMESPACE(std
)
57 * @addtogroup pointer_abstractions
61 /// 2.2.3.7 shared_ptr I/O
62 template<typename _Ch
, typename _Tr
, typename _Tp
, _Lock_policy _Lp
>
63 std::basic_ostream
<_Ch
, _Tr
>&
64 operator<<(std::basic_ostream
<_Ch
, _Tr
>& __os
,
65 const __shared_ptr
<_Tp
, _Lp
>& __p
)
71 /// 2.2.3.10 shared_ptr get_deleter (experimental)
72 template<typename _Del
, typename _Tp
, _Lock_policy _Lp
>
74 get_deleter(const __shared_ptr
<_Tp
, _Lp
>& __p
)
77 return static_cast<_Del
*>(__p
._M_get_deleter(typeid(_Del
)));
85 * @brief A smart pointer with reference-counted copy semantics.
87 * The object pointed to is deleted when the last shared_ptr pointing to
88 * it is destroyed or reset.
90 template<typename _Tp
>
91 class shared_ptr
: public __shared_ptr
<_Tp
>
95 * @brief Construct an empty %shared_ptr.
96 * @post use_count()==0 && get()==0
98 shared_ptr() : __shared_ptr
<_Tp
>() { }
101 * @brief Construct a %shared_ptr that owns the pointer @a __p.
102 * @param __p A pointer that is convertible to element_type*.
103 * @post use_count() == 1 && get() == __p
104 * @throw std::bad_alloc, in which case @c delete @a __p is called.
106 template<typename _Tp1
>
107 explicit shared_ptr(_Tp1
* __p
) : __shared_ptr
<_Tp
>(__p
) { }
110 * @brief Construct a %shared_ptr that owns the pointer @a __p
111 * and the deleter @a __d.
112 * @param __p A pointer.
113 * @param __d A deleter.
114 * @post use_count() == 1 && get() == __p
115 * @throw std::bad_alloc, in which case @a __d(__p) is called.
117 * Requirements: _Deleter's copy constructor and destructor must
120 * __shared_ptr will release __p by calling __d(__p)
122 template<typename _Tp1
, typename _Deleter
>
123 shared_ptr(_Tp1
* __p
, _Deleter __d
) : __shared_ptr
<_Tp
>(__p
, __d
) { }
126 * @brief Construct a %shared_ptr that owns the pointer @a __p
127 * and the deleter @a __d.
128 * @param __p A pointer.
129 * @param __d A deleter.
130 * @param __a An allocator.
131 * @post use_count() == 1 && get() == __p
132 * @throw std::bad_alloc, in which case @a __d(__p) is called.
134 * Requirements: _Deleter's copy constructor and destructor must
135 * not throw _Alloc's copy constructor and destructor must not
138 * __shared_ptr will release __p by calling __d(__p)
140 template<typename _Tp1
, typename _Deleter
, typename _Alloc
>
141 shared_ptr(_Tp1
* __p
, _Deleter __d
, const _Alloc
& __a
)
142 : __shared_ptr
<_Tp
>(__p
, __d
, __a
) { }
144 // Aliasing constructor
147 * @brief Constructs a %shared_ptr instance that stores @a __p
148 * and shares ownership with @a __r.
149 * @param __r A %shared_ptr.
150 * @param __p A pointer that will remain valid while @a *__r is valid.
151 * @post get() == __p && use_count() == __r.use_count()
153 * This can be used to construct a @c shared_ptr to a sub-object
154 * of an object managed by an existing @c shared_ptr.
157 * shared_ptr< pair<int,int> > pii(new pair<int,int>());
158 * shared_ptr<int> pi(pii, &pii->first);
159 * assert(pii.use_count() == 2);
162 template<typename _Tp1
>
163 shared_ptr(const shared_ptr
<_Tp1
>& __r
, _Tp
* __p
)
164 : __shared_ptr
<_Tp
>(__r
, __p
) { }
167 * @brief If @a __r is empty, constructs an empty %shared_ptr;
168 * otherwise construct a %shared_ptr that shares ownership
170 * @param __r A %shared_ptr.
171 * @post get() == __r.get() && use_count() == __r.use_count()
173 template<typename _Tp1
>
174 shared_ptr(const shared_ptr
<_Tp1
>& __r
) : __shared_ptr
<_Tp
>(__r
) { }
177 * @brief Move-constructs a %shared_ptr instance from @a __r.
178 * @param __r A %shared_ptr rvalue.
179 * @post *this contains the old value of @a __r, @a __r is empty.
181 shared_ptr(shared_ptr
&& __r
)
182 : __shared_ptr
<_Tp
>(std::move(__r
)) { }
185 * @brief Move-constructs a %shared_ptr instance from @a __r.
186 * @param __r A %shared_ptr rvalue.
187 * @post *this contains the old value of @a __r, @a __r is empty.
189 template<typename _Tp1
>
190 shared_ptr(shared_ptr
<_Tp1
>&& __r
)
191 : __shared_ptr
<_Tp
>(std::move(__r
)) { }
194 * @brief Constructs a %shared_ptr that shares ownership with @a __r
195 * and stores a copy of the pointer stored in @a __r.
196 * @param __r A weak_ptr.
197 * @post use_count() == __r.use_count()
198 * @throw bad_weak_ptr when __r.expired(),
199 * in which case the constructor has no effect.
201 template<typename _Tp1
>
202 explicit shared_ptr(const weak_ptr
<_Tp1
>& __r
)
203 : __shared_ptr
<_Tp
>(__r
) { }
205 #if _GLIBCXX_DEPRECATED
206 template<typename _Tp1
>
208 shared_ptr(std::auto_ptr
<_Tp1
>&& __r
)
209 : __shared_ptr
<_Tp
>(std::move(__r
)) { }
212 template<typename _Tp1
, typename _Del
>
213 explicit shared_ptr(const std::unique_ptr
<_Tp1
, _Del
>&) = delete;
215 template<typename _Tp1
, typename _Del
>
216 explicit shared_ptr(std::unique_ptr
<_Tp1
, _Del
>&& __r
)
217 : __shared_ptr
<_Tp
>(std::move(__r
)) { }
219 template<typename _Tp1
>
221 operator=(const shared_ptr
<_Tp1
>& __r
) // never throws
223 this->__shared_ptr
<_Tp
>::operator=(__r
);
227 #if _GLIBCXX_DEPRECATED
228 template<typename _Tp1
>
230 operator=(std::auto_ptr
<_Tp1
>&& __r
)
232 this->__shared_ptr
<_Tp
>::operator=(std::move(__r
));
238 operator=(shared_ptr
&& __r
)
240 this->__shared_ptr
<_Tp
>::operator=(std::move(__r
));
246 operator=(shared_ptr
<_Tp1
>&& __r
)
248 this->__shared_ptr
<_Tp
>::operator=(std::move(__r
));
252 template<typename _Tp1
, typename _Del
>
254 operator=(const std::unique_ptr
<_Tp1
, _Del
>& __r
) = delete;
256 template<typename _Tp1
, typename _Del
>
258 operator=(std::unique_ptr
<_Tp1
, _Del
>&& __r
)
260 this->__shared_ptr
<_Tp
>::operator=(std::move(__r
));
265 // This constructor is non-standard, it is used by allocate_shared.
266 template<typename _Alloc
, typename
... _Args
>
267 shared_ptr(_Sp_make_shared_tag __tag
, _Alloc __a
, _Args
&&... __args
)
268 : __shared_ptr
<_Tp
>(__tag
, __a
, std::forward
<_Args
>(__args
)...)
271 template<typename _Tp1
, typename _Alloc
, typename
... _Args
>
272 friend shared_ptr
<_Tp1
>
273 allocate_shared(_Alloc __a
, _Args
&&... __args
);
276 // 20.8.13.2.7 shared_ptr comparisons
277 template<typename _Tp1
, typename _Tp2
>
279 operator==(const shared_ptr
<_Tp1
>& __a
, const shared_ptr
<_Tp2
>& __b
)
280 { return __a
.get() == __b
.get(); }
282 template<typename _Tp1
, typename _Tp2
>
284 operator!=(const shared_ptr
<_Tp1
>& __a
, const shared_ptr
<_Tp2
>& __b
)
285 { return __a
.get() != __b
.get(); }
287 template<typename _Tp1
, typename _Tp2
>
289 operator<(const shared_ptr
<_Tp1
>& __a
, const shared_ptr
<_Tp2
>& __b
)
290 { return __a
.get() < __b
.get(); }
292 template<typename _Tp
>
293 struct less
<shared_ptr
<_Tp
>> : public _Sp_less
<shared_ptr
<_Tp
>>
296 // 20.8.13.2.9 shared_ptr specialized algorithms.
297 template<typename _Tp
>
299 swap(shared_ptr
<_Tp
>& __a
, shared_ptr
<_Tp
>& __b
)
302 // 20.8.13.2.10 shared_ptr casts.
303 template<typename _Tp
, typename _Tp1
>
304 inline shared_ptr
<_Tp
>
305 static_pointer_cast(const shared_ptr
<_Tp1
>& __r
)
306 { return shared_ptr
<_Tp
>(__r
, static_cast<_Tp
*>(__r
.get())); }
308 template<typename _Tp
, typename _Tp1
>
309 inline shared_ptr
<_Tp
>
310 const_pointer_cast(const shared_ptr
<_Tp1
>& __r
)
311 { return shared_ptr
<_Tp
>(__r
, const_cast<_Tp
*>(__r
.get())); }
313 template<typename _Tp
, typename _Tp1
>
314 inline shared_ptr
<_Tp
>
315 dynamic_pointer_cast(const shared_ptr
<_Tp1
>& __r
)
317 if (_Tp
* __p
= dynamic_cast<_Tp
*>(__r
.get()))
318 return shared_ptr
<_Tp
>(__r
, __p
);
319 return shared_ptr
<_Tp
>();
324 * @brief A smart pointer with weak semantics.
326 * With forwarding constructors and assignment operators.
328 template<typename _Tp
>
329 class weak_ptr
: public __weak_ptr
<_Tp
>
332 weak_ptr() : __weak_ptr
<_Tp
>() { }
334 template<typename _Tp1
>
335 weak_ptr(const weak_ptr
<_Tp1
>& __r
)
336 : __weak_ptr
<_Tp
>(__r
) { }
338 template<typename _Tp1
>
339 weak_ptr(const shared_ptr
<_Tp1
>& __r
)
340 : __weak_ptr
<_Tp
>(__r
) { }
342 template<typename _Tp1
>
344 operator=(const weak_ptr
<_Tp1
>& __r
) // never throws
346 this->__weak_ptr
<_Tp
>::operator=(__r
);
350 template<typename _Tp1
>
352 operator=(const shared_ptr
<_Tp1
>& __r
) // never throws
354 this->__weak_ptr
<_Tp
>::operator=(__r
);
359 lock() const // never throws
363 return shared_ptr
<_Tp
>();
367 return shared_ptr
<_Tp
>(*this);
369 __catch(const bad_weak_ptr
&)
371 return shared_ptr
<_Tp
>();
374 return this->expired() ? shared_ptr
<_Tp
>() : shared_ptr
<_Tp
>(*this);
379 template<typename _Tp1
>
380 bool operator<(const weak_ptr
<_Tp1
>&) const = delete;
381 template<typename _Tp1
>
382 bool operator<=(const weak_ptr
<_Tp1
>&) const = delete;
383 template<typename _Tp1
>
384 bool operator>(const weak_ptr
<_Tp1
>&) const = delete;
385 template<typename _Tp1
>
386 bool operator>=(const weak_ptr
<_Tp1
>&) const = delete;
389 // 20.8.13.3.7 weak_ptr specialized algorithms.
390 template<typename _Tp
>
392 swap(weak_ptr
<_Tp
>& __a
, weak_ptr
<_Tp
>& __b
)
396 /// Primary template owner_less
397 template<typename _Tp
>
400 /// Partial specialization of owner_less for shared_ptr.
401 template<typename _Tp
>
402 struct owner_less
<shared_ptr
<_Tp
>>
403 : public _Sp_owner_less
<shared_ptr
<_Tp
>, weak_ptr
<_Tp
>>
406 /// Partial specialization of owner_less for weak_ptr.
407 template<typename _Tp
>
408 struct owner_less
<weak_ptr
<_Tp
>>
409 : public _Sp_owner_less
<weak_ptr
<_Tp
>, shared_ptr
<_Tp
>>
413 * @brief Base class allowing use of member function shared_from_this.
415 template<typename _Tp
>
416 class enable_shared_from_this
419 enable_shared_from_this() { }
421 enable_shared_from_this(const enable_shared_from_this
&) { }
423 enable_shared_from_this
&
424 operator=(const enable_shared_from_this
&)
427 ~enable_shared_from_this() { }
432 { return shared_ptr
<_Tp
>(this->_M_weak_this
); }
434 shared_ptr
<const _Tp
>
435 shared_from_this() const
436 { return shared_ptr
<const _Tp
>(this->_M_weak_this
); }
439 template<typename _Tp1
>
441 _M_weak_assign(_Tp1
* __p
, const __shared_count
<>& __n
) const
442 { _M_weak_this
._M_assign(__p
, __n
); }
444 template<typename _Tp1
>
446 __enable_shared_from_this_helper(const __shared_count
<>& __pn
,
447 const enable_shared_from_this
* __pe
,
451 __pe
->_M_weak_assign(const_cast<_Tp1
*>(__px
), __pn
);
454 mutable weak_ptr
<_Tp
> _M_weak_this
;
458 * @brief Create an object that is owned by a shared_ptr.
459 * @param __a An allocator.
460 * @param __args Arguments for the @a _Tp object's constructor.
461 * @return A shared_ptr that owns the newly created object.
462 * @throw An exception thrown from @a _Alloc::allocate or from the
463 * constructor of @a _Tp.
465 * A copy of @a __a will be used to allocate memory for the shared_ptr
466 * and the new object.
468 template<typename _Tp
, typename _Alloc
, typename
... _Args
>
469 inline shared_ptr
<_Tp
>
470 allocate_shared(_Alloc __a
, _Args
&&... __args
)
472 return shared_ptr
<_Tp
>(_Sp_make_shared_tag(), std::forward
<_Alloc
>(__a
),
473 std::forward
<_Args
>(__args
)...);
477 * @brief Create an object that is owned by a shared_ptr.
478 * @param __args Arguments for the @a _Tp object's constructor.
479 * @return A shared_ptr that owns the newly created object.
480 * @throw std::bad_alloc, or an exception thrown from the
481 * constructor of @a _Tp.
483 template<typename _Tp
, typename
... _Args
>
484 inline shared_ptr
<_Tp
>
485 make_shared(_Args
&&... __args
)
487 typedef typename
std::remove_const
<_Tp
>::type _Tp_nc
;
488 return allocate_shared
<_Tp
>(std::allocator
<_Tp_nc
>(),
489 std::forward
<_Args
>(__args
)...);
492 // @} group pointer_abstractions
494 _GLIBCXX_END_NAMESPACE
496 #endif // _SHARED_PTR_H