1 // shared_ptr and weak_ptr implementation -*- C++ -*-
3 // Copyright (C) 2007, 2008, 2009 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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
53 # include <c++0x_warning.h>
56 #include <bits/shared_ptr_base.h>
58 _GLIBCXX_BEGIN_NAMESPACE(std)
61 * @addtogroup pointer_abstractions
65 /// 2.2.3.7 shared_ptr I/O
66 template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>
67 std::basic_ostream<_Ch, _Tr>&
68 operator<<(std::basic_ostream<_Ch, _Tr>& __os,
69 const __shared_ptr<_Tp, _Lp>& __p)
75 /// 2.2.3.10 shared_ptr get_deleter (experimental)
76 template<typename _Del, typename _Tp, _Lock_policy _Lp>
78 get_deleter(const __shared_ptr<_Tp, _Lp>& __p)
79 { return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); }
83 * @brief A smart pointer with reference-counted copy semantics.
85 * The object pointed to is deleted when the last shared_ptr pointing to
86 * it is destroyed or reset.
88 template<typename _Tp>
89 class shared_ptr : public __shared_ptr<_Tp>
93 * @brief Construct an empty %shared_ptr.
94 * @post use_count()==0 && get()==0
96 shared_ptr() : __shared_ptr<_Tp>() { }
99 * @brief Construct a %shared_ptr that owns the pointer @a __p.
100 * @param __p A pointer that is convertible to element_type*.
101 * @post use_count() == 1 && get() == __p
102 * @throw std::bad_alloc, in which case @c delete @a __p is called.
104 template<typename _Tp1>
105 explicit shared_ptr(_Tp1* __p) : __shared_ptr<_Tp>(__p) { }
108 * @brief Construct a %shared_ptr that owns the pointer @a __p
109 * and the deleter @a __d.
110 * @param __p A pointer.
111 * @param __d A deleter.
112 * @post use_count() == 1 && get() == __p
113 * @throw std::bad_alloc, in which case @a __d(__p) is called.
115 * Requirements: _Deleter's copy constructor and destructor must
118 * __shared_ptr will release __p by calling __d(__p)
120 template<typename _Tp1, typename _Deleter>
121 shared_ptr(_Tp1* __p, _Deleter __d) : __shared_ptr<_Tp>(__p, __d) { }
124 * @brief Construct a %shared_ptr that owns the pointer @a __p
125 * and the deleter @a __d.
126 * @param __p A pointer.
127 * @param __d A deleter.
128 * @param __a An allocator.
129 * @post use_count() == 1 && get() == __p
130 * @throw std::bad_alloc, in which case @a __d(__p) is called.
132 * Requirements: _Deleter's copy constructor and destructor must
133 * not throw _Alloc's copy constructor and destructor must not
136 * __shared_ptr will release __p by calling __d(__p)
138 template<typename _Tp1, typename _Deleter, typename _Alloc>
139 shared_ptr(_Tp1* __p, _Deleter __d, const _Alloc& __a)
140 : __shared_ptr<_Tp>(__p, __d, __a) { }
142 // Aliasing constructor
145 * @brief Constructs a %shared_ptr instance that stores @a __p
146 * and shares ownership with @a __r.
147 * @param __r A %shared_ptr.
148 * @param __p A pointer that will remain valid while @a *__r is valid.
149 * @post get() == __p && use_count() == __r.use_count()
151 * This can be used to construct a @c shared_ptr to a sub-object
152 * of an object managed by an existing @c shared_ptr.
155 * shared_ptr< pair<int,int> > pii(new pair<int,int>());
156 * shared_ptr<int> pi(pii, &pii->first);
157 * assert(pii.use_count() == 2);
160 template<typename _Tp1>
161 shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p)
162 : __shared_ptr<_Tp>(__r, __p) { }
165 * @brief If @a __r is empty, constructs an empty %shared_ptr;
166 * otherwise construct a %shared_ptr that shares ownership
168 * @param __r A %shared_ptr.
169 * @post get() == __r.get() && use_count() == __r.use_count()
171 template<typename _Tp1>
172 shared_ptr(const shared_ptr<_Tp1>& __r) : __shared_ptr<_Tp>(__r) { }
175 * @brief Move-constructs a %shared_ptr instance from @a __r.
176 * @param __r A %shared_ptr rvalue.
177 * @post *this contains the old value of @a __r, @a __r is empty.
179 shared_ptr(shared_ptr&& __r)
180 : __shared_ptr<_Tp>(std::move(__r)) { }
183 * @brief Move-constructs a %shared_ptr instance from @a __r.
184 * @param __r A %shared_ptr rvalue.
185 * @post *this contains the old value of @a __r, @a __r is empty.
187 template<typename _Tp1>
188 shared_ptr(shared_ptr<_Tp1>&& __r)
189 : __shared_ptr<_Tp>(std::move(__r)) { }
192 * @brief Constructs a %shared_ptr that shares ownership with @a __r
193 * and stores a copy of the pointer stored in @a __r.
194 * @param __r A weak_ptr.
195 * @post use_count() == __r.use_count()
196 * @throw bad_weak_ptr when __r.expired(),
197 * in which case the constructor has no effect.
199 template<typename _Tp1>
200 explicit shared_ptr(const weak_ptr<_Tp1>& __r)
201 : __shared_ptr<_Tp>(__r) { }
203 #if _GLIBCXX_DEPRECATED
204 template<typename _Tp1>
206 shared_ptr(std::auto_ptr<_Tp1>&& __r)
207 : __shared_ptr<_Tp>(std::move(__r)) { }
210 template<typename _Tp1, typename _Del>
211 explicit shared_ptr(const std::unique_ptr<_Tp1, _Del>&) = delete;
213 template<typename _Tp1, typename _Del>
214 explicit shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
215 : __shared_ptr<_Tp>(std::move(__r)) { }
217 template<typename _Tp1>
219 operator=(const shared_ptr<_Tp1>& __r) // never throws
221 this->__shared_ptr<_Tp>::operator=(__r);
225 #if _GLIBCXX_DEPRECATED
226 template<typename _Tp1>
228 operator=(std::auto_ptr<_Tp1>&& __r)
230 this->__shared_ptr<_Tp>::operator=(std::move(__r));
236 operator=(shared_ptr&& __r)
238 this->__shared_ptr<_Tp>::operator=(std::move(__r));
244 operator=(shared_ptr<_Tp1>&& __r)
246 this->__shared_ptr<_Tp>::operator=(std::move(__r));
250 template<typename _Tp1, typename _Del>
252 operator=(const std::unique_ptr<_Tp1, _Del>& __r) = delete;
254 template<typename _Tp1, typename _Del>
256 operator=(std::unique_ptr<_Tp1, _Del>&& __r)
258 this->__shared_ptr<_Tp>::operator=(std::move(__r));
263 // This constructor is non-standard, it is used by allocate_shared.
264 template<typename _Alloc, typename... _Args>
265 shared_ptr(_Sp_make_shared_tag __tag, _Alloc __a, _Args&&... __args)
266 : __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...)
269 template<typename _Tp1, typename _Alloc, typename... _Args>
270 friend shared_ptr<_Tp1>
271 allocate_shared(_Alloc __a, _Args&&... __args);
274 // 20.8.13.2.7 shared_ptr comparisons
275 template<typename _Tp1, typename _Tp2>
277 operator==(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
278 { return __a.get() == __b.get(); }
280 template<typename _Tp1, typename _Tp2>
282 operator!=(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
283 { return __a.get() != __b.get(); }
285 template<typename _Tp1, typename _Tp2>
287 operator<(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
288 { return __a.get() < __b.get(); }
290 template<typename _Tp>
291 struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>>
294 // 20.8.13.2.9 shared_ptr specialized algorithms.
295 template<typename _Tp>
297 swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b)
300 // 20.8.13.2.10 shared_ptr casts.
301 template<typename _Tp, typename _Tp1>
302 inline shared_ptr<_Tp>
303 static_pointer_cast(const shared_ptr<_Tp1>& __r)
304 { return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); }
306 template<typename _Tp, typename _Tp1>
307 inline shared_ptr<_Tp>
308 const_pointer_cast(const shared_ptr<_Tp1>& __r)
309 { return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); }
311 template<typename _Tp, typename _Tp1>
312 inline shared_ptr<_Tp>
313 dynamic_pointer_cast(const shared_ptr<_Tp1>& __r)
315 if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
316 return shared_ptr<_Tp>(__r, __p);
317 return shared_ptr<_Tp>();
322 * @brief A smart pointer with weak semantics.
324 * With forwarding constructors and assignment operators.
326 template<typename _Tp>
327 class weak_ptr : public __weak_ptr<_Tp>
330 weak_ptr() : __weak_ptr<_Tp>() { }
332 template<typename _Tp1>
333 weak_ptr(const weak_ptr<_Tp1>& __r)
334 : __weak_ptr<_Tp>(__r) { }
336 template<typename _Tp1>
337 weak_ptr(const shared_ptr<_Tp1>& __r)
338 : __weak_ptr<_Tp>(__r) { }
340 template<typename _Tp1>
342 operator=(const weak_ptr<_Tp1>& __r) // never throws
344 this->__weak_ptr<_Tp>::operator=(__r);
348 template<typename _Tp1>
350 operator=(const shared_ptr<_Tp1>& __r) // never throws
352 this->__weak_ptr<_Tp>::operator=(__r);
357 lock() const // never throws
361 return shared_ptr<_Tp>();
365 return shared_ptr<_Tp>(*this);
367 __catch(const bad_weak_ptr&)
369 return shared_ptr<_Tp>();
372 return this->expired() ? shared_ptr<_Tp>() : shared_ptr<_Tp>(*this);
377 template<typename _Tp1>
378 bool operator<(const weak_ptr<_Tp1>&) const = delete;
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;
387 // 20.8.13.3.7 weak_ptr specialized algorithms.
388 template<typename _Tp>
390 swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b)
394 /// Primary template owner_less
395 template<typename _Tp>
398 /// Partial specialization of owner_less for shared_ptr.
399 template<typename _Tp>
400 struct owner_less<shared_ptr<_Tp>>
401 : public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
404 /// Partial specialization of owner_less for weak_ptr.
405 template<typename _Tp>
406 struct owner_less<weak_ptr<_Tp>>
407 : public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
411 * @brief Base class allowing use of member function shared_from_this.
413 template<typename _Tp>
414 class enable_shared_from_this
417 enable_shared_from_this() { }
419 enable_shared_from_this(const enable_shared_from_this&) { }
421 enable_shared_from_this&
422 operator=(const enable_shared_from_this&)
425 ~enable_shared_from_this() { }
430 { return shared_ptr<_Tp>(this->_M_weak_this); }
432 shared_ptr<const _Tp>
433 shared_from_this() const
434 { return shared_ptr<const _Tp>(this->_M_weak_this); }
437 template<typename _Tp1>
439 _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const
440 { _M_weak_this._M_assign(__p, __n); }
442 template<typename _Tp1>
444 __enable_shared_from_this_helper(const __shared_count<>& __pn,
445 const enable_shared_from_this* __pe,
449 __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
452 mutable weak_ptr<_Tp> _M_weak_this;
456 * @brief Create an object that is owned by a shared_ptr.
457 * @param __a An allocator.
458 * @param __args Arguments for the @a _Tp object's constructor.
459 * @return A shared_ptr that owns the newly created object.
460 * @throw An exception thrown from @a _Alloc::allocate or from the
461 * constructor of @a _Tp.
463 * A copy of @a __a will be used to allocate memory for the shared_ptr
464 * and the new object.
466 template<typename _Tp, typename _Alloc, typename... _Args>
467 inline shared_ptr<_Tp>
468 allocate_shared(_Alloc __a, _Args&&... __args)
470 return shared_ptr<_Tp>(_Sp_make_shared_tag(), std::forward<_Alloc>(__a),
471 std::forward<_Args>(__args)...);
475 * @brief Create an object that is owned by a shared_ptr.
476 * @param __args Arguments for the @a _Tp object's constructor.
477 * @return A shared_ptr that owns the newly created object.
478 * @throw std::bad_alloc, or an exception thrown from the
479 * constructor of @a _Tp.
481 template<typename _Tp, typename... _Args>
482 inline shared_ptr<_Tp>
483 make_shared(_Args&&... __args)
485 typedef typename std::remove_const<_Tp>::type _Tp_nc;
486 return allocate_shared<_Tp>(std::allocator<_Tp_nc>(),
487 std::forward<_Args>(__args)...);
490 // @} group pointer_abstractions
492 _GLIBCXX_END_NAMESPACE
494 #endif // _SHARED_PTR_H