1 // shared_ptr and weak_ptr implementation details -*- 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_base.h
45 * This is an internal header file, included by other library headers.
46 * You should not attempt to use it directly.
49 #ifndef _SHARED_PTR_BASE_H
50 #define _SHARED_PTR_BASE_H 1
52 _GLIBCXX_BEGIN_NAMESPACE(std)
54 // Forward declarations.
55 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
58 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
61 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
62 class __enable_shared_from_this;
64 template<typename _Tp>
67 template<typename _Tp>
70 template<typename _Tp>
73 template<typename _Tp>
74 class enable_shared_from_this;
76 template<_Lock_policy _Lp = __default_lock_policy>
79 template<_Lock_policy _Lp = __default_lock_policy>
83 // Counted ptr with no deleter or allocator support
84 template<typename _Ptr, _Lock_policy _Lp>
85 class _Sp_counted_ptr : public _Sp_counted_base<_Lp>
88 _Sp_counted_ptr(_Ptr __p)
92 _M_dispose() // nothrow
96 _M_destroy() // nothrow
100 _M_get_deleter(const std::type_info& __ti)
103 _Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
104 _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
107 _Ptr _M_ptr; // copy constructor must not throw
110 // Support for custom deleter and/or allocator
111 template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
112 class _Sp_counted_deleter : public _Sp_counted_ptr<_Ptr, _Lp>
114 typedef typename _Alloc::template
115 rebind<_Sp_counted_deleter>::other _My_alloc_type;
117 // Helper class that stores the Deleter and also acts as an allocator.
118 // Used to dispose of the owned pointer and the internal refcount
119 // Requires that copies of _Alloc can free each other's memory.
121 : public _My_alloc_type // copy constructor must not throw
123 _Deleter _M_del; // copy constructor must not throw
124 _My_Deleter(_Deleter __d, const _Alloc& __a)
125 : _My_alloc_type(__a), _M_del(__d) { }
129 typedef _Sp_counted_ptr<_Ptr, _Lp> _Base_type;
132 // __d(__p) must not throw.
133 _Sp_counted_deleter(_Ptr __p, _Deleter __d)
134 : _Base_type(__p), _M_del(__d, _Alloc()) { }
136 // __d(__p) must not throw.
137 _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a)
138 : _Base_type(__p), _M_del(__d, __a) { }
141 _M_dispose() // nothrow
142 { _M_del._M_del(_Base_type::_M_ptr); }
145 _M_destroy() // nothrow
147 _My_alloc_type __a(_M_del);
148 this->~_Sp_counted_deleter();
149 __a.deallocate(this, 1);
153 _M_get_deleter(const std::type_info& __ti)
156 return __ti == typeid(_Deleter) ? &_M_del._M_del : 0;
163 _My_Deleter _M_del; // copy constructor must not throw
166 // helpers for make_shared / allocate_shared
168 template<typename _Tp>
169 struct _Sp_destroy_inplace
171 void operator()(_Tp* __p) const { if (__p) __p->~_Tp(); }
174 struct _Sp_make_shared_tag { };
176 template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
177 class _Sp_counted_ptr_inplace
178 : public _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp>
180 typedef _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp>
184 _Sp_counted_ptr_inplace(_Alloc __a)
185 : _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a)
188 void* __p = &_M_storage;
189 ::new (__p) _Tp(); // might throw
190 _Base_type::_Base_type::_M_ptr = static_cast<_Tp*>(__p);
193 template<typename... _Args>
194 _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
195 : _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a)
198 void* __p = &_M_storage;
199 ::new (__p) _Tp(std::forward<_Args>(__args)...); // might throw
200 _Base_type::_Base_type::_M_ptr = static_cast<_Tp*>(__p);
203 // Override because the allocator needs to know the dynamic type
205 _M_destroy() // nothrow
207 typedef typename _Alloc::template
208 rebind<_Sp_counted_ptr_inplace>::other _My_alloc_type;
209 _My_alloc_type __a(_Base_type::_M_del);
210 this->~_Sp_counted_ptr_inplace();
211 __a.deallocate(this, 1);
214 // Sneaky trick so __shared_ptr can get the managed pointer
216 _M_get_deleter(const std::type_info& __ti)
219 return __ti == typeid(_Sp_make_shared_tag)
220 ? static_cast<void*>(&_M_storage)
221 : _Base_type::_M_get_deleter(__ti);
228 typename aligned_storage<sizeof(_Tp), alignment_of<_Tp>::value>::type
232 template<_Lock_policy _Lp>
236 __shared_count() : _M_pi(0) // nothrow
239 template<typename _Ptr>
240 __shared_count(_Ptr __p) : _M_pi(0)
244 _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
249 __throw_exception_again;
253 template<typename _Ptr, typename _Deleter>
254 __shared_count(_Ptr __p, _Deleter __d) : _M_pi(0)
256 // The allocator's value_type doesn't matter, will rebind it anyway.
257 typedef std::allocator<int> _Alloc;
258 typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
259 typedef std::allocator<_Sp_cd_type> _Alloc2;
263 _M_pi = __a2.allocate(1);
264 ::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d);
268 __d(__p); // Call _Deleter on __p.
270 __a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1);
271 __throw_exception_again;
275 template<typename _Ptr, typename _Deleter, typename _Alloc>
276 __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
278 typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
279 typedef typename _Alloc::template rebind<_Sp_cd_type>::other _Alloc2;
283 _M_pi = __a2.allocate(1);
284 ::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d, __a);
288 __d(__p); // Call _Deleter on __p.
290 __a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1);
291 __throw_exception_again;
295 template<typename _Tp, typename _Alloc, typename... _Args>
296 __shared_count(_Sp_make_shared_tag, _Tp*, _Alloc __a, _Args&&... __args)
299 typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
300 typedef typename _Alloc::template rebind<_Sp_cp_type>::other _Alloc2;
304 _M_pi = __a2.allocate(1);
305 ::new(static_cast<void*>(_M_pi)) _Sp_cp_type(__a,
306 std::forward<_Args>(__args)...);
311 __a2.deallocate(static_cast<_Sp_cp_type*>(_M_pi), 1);
312 __throw_exception_again;
316 #if _GLIBCXX_DEPRECATED
317 // Special case for auto_ptr<_Tp> to provide the strong guarantee.
318 template<typename _Tp>
319 explicit __shared_count(std::auto_ptr<_Tp>&& __r)
320 : _M_pi(new _Sp_counted_ptr<_Tp*, _Lp>(__r.get()))
324 // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
325 template<typename _Tp, typename _Del>
326 explicit __shared_count(std::unique_ptr<_Tp, _Del>&& __r)
327 : _M_pi(_S_create_from_up(std::move(__r)))
330 // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
331 explicit __shared_count(const __weak_count<_Lp>& __r);
333 ~__shared_count() // nothrow
339 __shared_count(const __shared_count& __r)
340 : _M_pi(__r._M_pi) // nothrow
343 _M_pi->_M_add_ref_copy();
347 operator=(const __shared_count& __r) // nothrow
349 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
353 __tmp->_M_add_ref_copy();
362 _M_swap(__shared_count& __r) // nothrow
364 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
370 _M_get_use_count() const // nothrow
371 { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
374 _M_unique() const // nothrow
375 { return this->_M_get_use_count() == 1; }
378 _M_get_deleter(const std::type_info& __ti) const
379 { return _M_pi ? _M_pi->_M_get_deleter(__ti) : 0; }
382 _M_less(const __shared_count& __rhs) const
383 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
386 _M_less(const __weak_count<_Lp>& __rhs) const
387 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
389 // Friend function injected into enclosing namespace and found by ADL
391 operator==(const __shared_count& __a, const __shared_count& __b)
392 { return __a._M_pi == __b._M_pi; }
395 friend class __weak_count<_Lp>;
397 template<typename _Tp, typename _Del>
398 static _Sp_counted_base<_Lp>*
399 _S_create_from_up(std::unique_ptr<_Tp, _Del>&& __r,
400 typename std::enable_if<!std::is_reference<_Del>::value>::type* = 0)
402 return new _Sp_counted_deleter<_Tp*, _Del, std::allocator<_Tp>,
403 _Lp>(__r.get(), __r.get_deleter());
406 template<typename _Tp, typename _Del>
407 static _Sp_counted_base<_Lp>*
408 _S_create_from_up(std::unique_ptr<_Tp, _Del>&& __r,
409 typename std::enable_if<std::is_reference<_Del>::value>::type* = 0)
411 typedef typename std::remove_reference<_Del>::type _Del1;
412 typedef std::reference_wrapper<_Del1> _Del2;
413 return new _Sp_counted_deleter<_Tp*, _Del2, std::allocator<_Tp>,
414 _Lp>(__r.get(), std::ref(__r.get_deleter()));
417 _Sp_counted_base<_Lp>* _M_pi;
421 template<_Lock_policy _Lp>
425 __weak_count() : _M_pi(0) // nothrow
428 __weak_count(const __shared_count<_Lp>& __r) : _M_pi(__r._M_pi) // nothrow
431 _M_pi->_M_weak_add_ref();
434 __weak_count(const __weak_count<_Lp>& __r) : _M_pi(__r._M_pi) // nothrow
437 _M_pi->_M_weak_add_ref();
440 ~__weak_count() // nothrow
443 _M_pi->_M_weak_release();
447 operator=(const __shared_count<_Lp>& __r) // nothrow
449 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
451 __tmp->_M_weak_add_ref();
453 _M_pi->_M_weak_release();
459 operator=(const __weak_count<_Lp>& __r) // nothrow
461 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
463 __tmp->_M_weak_add_ref();
465 _M_pi->_M_weak_release();
471 _M_swap(__weak_count<_Lp>& __r) // nothrow
473 _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
479 _M_get_use_count() const // nothrow
480 { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
483 _M_less(const __weak_count& __rhs) const
484 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
487 _M_less(const __shared_count<_Lp>& __rhs) const
488 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
490 // Friend function injected into enclosing namespace and found by ADL
492 operator==(const __weak_count& __a, const __weak_count& __b)
493 { return __a._M_pi == __b._M_pi; }
496 friend class __shared_count<_Lp>;
498 _Sp_counted_base<_Lp>* _M_pi;
501 // Now that __weak_count is defined we can define this constructor:
502 template<_Lock_policy _Lp>
503 inline __shared_count<_Lp>:: __shared_count(const __weak_count<_Lp>& __r)
507 _M_pi->_M_add_ref_lock();
509 __throw_bad_weak_ptr();
513 // Support for enable_shared_from_this.
515 // Friend of __enable_shared_from_this.
516 template<_Lock_policy _Lp, typename _Tp1, typename _Tp2>
518 __enable_shared_from_this_helper(const __shared_count<_Lp>&,
519 const __enable_shared_from_this<_Tp1,
522 // Friend of enable_shared_from_this.
523 template<typename _Tp1, typename _Tp2>
525 __enable_shared_from_this_helper(const __shared_count<>&,
526 const enable_shared_from_this<_Tp1>*,
529 template<_Lock_policy _Lp>
531 __enable_shared_from_this_helper(const __shared_count<_Lp>&, ...)
535 template<typename _Tp, _Lock_policy _Lp>
539 typedef _Tp element_type;
541 __shared_ptr() : _M_ptr(0), _M_refcount() // never throws
544 template<typename _Tp1>
545 explicit __shared_ptr(_Tp1* __p) : _M_ptr(__p), _M_refcount(__p)
547 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
548 // __glibcxx_function_requires(_CompleteConcept<_Tp1*>)
549 __enable_shared_from_this_helper(_M_refcount, __p, __p);
552 template<typename _Tp1, typename _Deleter>
553 __shared_ptr(_Tp1* __p, _Deleter __d)
554 : _M_ptr(__p), _M_refcount(__p, __d)
556 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
557 // TODO requires _Deleter CopyConstructible and __d(__p) well-formed
558 __enable_shared_from_this_helper(_M_refcount, __p, __p);
561 template<typename _Tp1, typename _Deleter, typename _Alloc>
562 __shared_ptr(_Tp1* __p, _Deleter __d, const _Alloc& __a)
563 : _M_ptr(__p), _M_refcount(__p, __d, __a)
565 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
566 // TODO requires _Deleter CopyConstructible and __d(__p) well-formed
567 __enable_shared_from_this_helper(_M_refcount, __p, __p);
570 template<typename _Tp1>
571 __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, _Tp* __p)
572 : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
575 // generated copy constructor, assignment, destructor are fine.
577 template<typename _Tp1>
578 __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r)
579 : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
580 { __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) }
582 __shared_ptr(__shared_ptr&& __r)
583 : _M_ptr(__r._M_ptr), _M_refcount() // never throws
585 _M_refcount._M_swap(__r._M_refcount);
589 template<typename _Tp1>
590 __shared_ptr(__shared_ptr<_Tp1, _Lp>&& __r)
591 : _M_ptr(__r._M_ptr), _M_refcount() // never throws
593 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
594 _M_refcount._M_swap(__r._M_refcount);
598 template<typename _Tp1>
599 explicit __shared_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
600 : _M_refcount(__r._M_refcount) // may throw
602 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
604 // It is now safe to copy __r._M_ptr, as
605 // _M_refcount(__r._M_refcount) did not throw.
609 // If an exception is thrown this constructor has no effect.
610 template<typename _Tp1, typename _Del>
611 explicit __shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
612 : _M_ptr(__r.get()), _M_refcount()
614 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
615 _Tp1* __tmp = __r.get();
616 _M_refcount = __shared_count<_Lp>(std::move(__r));
617 __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp);
620 #if _GLIBCXX_DEPRECATED
621 // Postcondition: use_count() == 1 and __r.get() == 0
622 template<typename _Tp1>
623 explicit __shared_ptr(std::auto_ptr<_Tp1>&& __r)
624 : _M_ptr(__r.get()), _M_refcount()
626 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
627 // TODO requires _Tp1 is complete, delete __r.release() well-formed
628 _Tp1* __tmp = __r.get();
629 _M_refcount = __shared_count<_Lp>(std::move(__r));
630 __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp);
634 template<typename _Tp1>
636 operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws
639 _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
643 #if _GLIBCXX_DEPRECATED
644 template<typename _Tp1>
646 operator=(std::auto_ptr<_Tp1>&& __r)
648 __shared_ptr(std::move(__r)).swap(*this);
654 operator=(__shared_ptr&& __r)
656 __shared_ptr(std::move(__r)).swap(*this);
662 operator=(__shared_ptr<_Tp1, _Lp>&& __r)
664 __shared_ptr(std::move(__r)).swap(*this);
668 template<typename _Tp1, typename _Del>
670 operator=(std::unique_ptr<_Tp1, _Del>&& __r)
672 __shared_ptr(std::move(__r)).swap(*this);
677 reset() // never throws
678 { __shared_ptr().swap(*this); }
680 template<typename _Tp1>
682 reset(_Tp1* __p) // _Tp1 must be complete.
684 // Catch self-reset errors.
685 _GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr);
686 __shared_ptr(__p).swap(*this);
689 template<typename _Tp1, typename _Deleter>
691 reset(_Tp1* __p, _Deleter __d)
692 { __shared_ptr(__p, __d).swap(*this); }
694 template<typename _Tp1, typename _Deleter, typename _Alloc>
696 reset(_Tp1* __p, _Deleter __d, const _Alloc& __a)
697 { __shared_ptr(__p, __d, __a).swap(*this); }
699 // Allow class instantiation when _Tp is [cv-qual] void.
700 typename std::add_lvalue_reference<_Tp>::type
701 operator*() const // never throws
703 _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
708 operator->() const // never throws
710 _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
715 get() const // never throws
718 explicit operator bool() const // never throws
719 { return _M_ptr == 0 ? false : true; }
722 unique() const // never throws
723 { return _M_refcount._M_unique(); }
726 use_count() const // never throws
727 { return _M_refcount._M_get_use_count(); }
730 swap(__shared_ptr<_Tp, _Lp>& __other) // never throws
732 std::swap(_M_ptr, __other._M_ptr);
733 _M_refcount._M_swap(__other._M_refcount);
736 template<typename _Tp1>
738 owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const
739 { return _M_refcount._M_less(__rhs._M_refcount); }
741 template<typename _Tp1>
743 owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const
744 { return _M_refcount._M_less(__rhs._M_refcount); }
748 // This constructor is non-standard, it is used by allocate_shared.
749 template<typename _Alloc, typename... _Args>
750 __shared_ptr(_Sp_make_shared_tag __tag, _Alloc __a, _Args&&... __args)
751 : _M_ptr(), _M_refcount(__tag, (_Tp*)0, __a,
752 std::forward<_Args>(__args)...)
754 // _M_ptr needs to point to the newly constructed object.
755 // This relies on _Sp_counted_ptr_inplace::_M_get_deleter.
756 void* __p = _M_refcount._M_get_deleter(typeid(__tag));
757 _M_ptr = static_cast<_Tp*>(__p);
758 __enable_shared_from_this_helper(_M_refcount, _M_ptr, _M_ptr);
761 template<typename _Alloc>
764 void operator()(_Tp* __ptr)
766 _M_alloc.destroy(__ptr);
767 _M_alloc.deallocate(__ptr, 1);
772 template<typename _Alloc, typename... _Args>
773 __shared_ptr(_Sp_make_shared_tag __tag, _Alloc __a, _Args&&... __args)
774 : _M_ptr(), _M_refcount()
776 typedef typename _Alloc::template rebind<_Tp>::other _Alloc2;
777 _Deleter<_Alloc2> __del = { _Alloc2(__a) };
778 _M_ptr = __del._M_alloc.allocate(1);
781 __del._M_alloc.construct(_M_ptr, std::forward<_Args>(__args)...);
785 __del._M_alloc.deallocate(_M_ptr, 1);
786 __throw_exception_again;
788 __shared_count<_Lp> __count(_M_ptr, __del, __del._M_alloc);
789 _M_refcount._M_swap(__count);
790 __enable_shared_from_this_helper(_M_refcount, _M_ptr, _M_ptr);
794 template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
796 friend __shared_ptr<_Tp1, _Lp1>
797 __allocate_shared(_Alloc __a, _Args&&... __args);
801 _M_get_deleter(const std::type_info& __ti) const
802 { return _M_refcount._M_get_deleter(__ti); }
804 template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
805 template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
807 template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
808 friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&);
810 _Tp* _M_ptr; // Contained pointer.
811 __shared_count<_Lp> _M_refcount; // Reference counter.
815 // 20.8.13.2.7 shared_ptr comparisons
816 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
818 operator==(const __shared_ptr<_Tp1, _Lp>& __a,
819 const __shared_ptr<_Tp2, _Lp>& __b)
820 { return __a.get() == __b.get(); }
822 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
824 operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
825 const __shared_ptr<_Tp2, _Lp>& __b)
826 { return __a.get() != __b.get(); }
828 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
830 operator<(const __shared_ptr<_Tp1, _Lp>& __a,
831 const __shared_ptr<_Tp2, _Lp>& __b)
832 { return __a.get() < __b.get(); }
834 template<typename _Sp>
835 struct _Sp_less : public binary_function<_Sp, _Sp, bool>
838 operator()(const _Sp& __lhs, const _Sp& __rhs) const
840 typedef typename _Sp::element_type element_type;
841 return std::less<element_type*>()(__lhs.get(), __rhs.get());
845 template<typename _Tp, _Lock_policy _Lp>
846 struct less<__shared_ptr<_Tp, _Lp>>
847 : public _Sp_less<__shared_ptr<_Tp, _Lp>>
850 // XXX LessThanComparable<_Tp> concept should provide >, >= and <=
851 template<typename _Tp, _Lock_policy _Lp>
853 operator>(const __shared_ptr<_Tp, _Lp>& __a,
854 const __shared_ptr<_Tp, _Lp>& __b)
855 { return __a.get() > __b.get(); }
857 template<typename _Tp, _Lock_policy _Lp>
859 operator>=(const __shared_ptr<_Tp, _Lp>& __a,
860 const __shared_ptr<_Tp, _Lp>& __b)
861 { return __a.get() >= __b.get(); }
863 template<typename _Tp, _Lock_policy _Lp>
865 operator<=(const __shared_ptr<_Tp, _Lp>& __a,
866 const __shared_ptr<_Tp, _Lp>& __b)
867 { return __a.get() <= __b.get(); }
869 // 2.2.3.8 shared_ptr specialized algorithms.
870 template<typename _Tp, _Lock_policy _Lp>
872 swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b)
875 // 2.2.3.9 shared_ptr casts
877 // The seemingly equivalent code:
878 // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
879 // will eventually result in undefined behaviour, attempting to
880 // delete the same object twice.
881 /// static_pointer_cast
882 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
883 inline __shared_ptr<_Tp, _Lp>
884 static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
885 { return __shared_ptr<_Tp, _Lp>(__r, static_cast<_Tp*>(__r.get())); }
887 // The seemingly equivalent code:
888 // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
889 // will eventually result in undefined behaviour, attempting to
890 // delete the same object twice.
891 /// const_pointer_cast
892 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
893 inline __shared_ptr<_Tp, _Lp>
894 const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
895 { return __shared_ptr<_Tp, _Lp>(__r, const_cast<_Tp*>(__r.get())); }
897 // The seemingly equivalent code:
898 // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
899 // will eventually result in undefined behaviour, attempting to
900 // delete the same object twice.
901 /// dynamic_pointer_cast
902 template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
903 inline __shared_ptr<_Tp, _Lp>
904 dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
906 if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
907 return __shared_ptr<_Tp, _Lp>(__r, __p);
908 return __shared_ptr<_Tp, _Lp>();
912 template<typename _Tp, _Lock_policy _Lp>
916 typedef _Tp element_type;
918 __weak_ptr() : _M_ptr(0), _M_refcount() // never throws
921 // Generated copy constructor, assignment, destructor are fine.
923 // The "obvious" converting constructor implementation:
925 // template<typename _Tp1>
926 // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
927 // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
930 // has a serious problem.
932 // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
933 // conversion may require access to *__r._M_ptr (virtual inheritance).
935 // It is not possible to avoid spurious access violations since
936 // in multithreaded programs __r._M_ptr may be invalidated at any point.
937 template<typename _Tp1>
938 __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
939 : _M_refcount(__r._M_refcount) // never throws
941 __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
942 _M_ptr = __r.lock().get();
945 template<typename _Tp1>
946 __weak_ptr(const __shared_ptr<_Tp1, _Lp>& __r)
947 : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
948 { __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) }
950 template<typename _Tp1>
952 operator=(const __weak_ptr<_Tp1, _Lp>& __r) // never throws
954 _M_ptr = __r.lock().get();
955 _M_refcount = __r._M_refcount;
959 template<typename _Tp1>
961 operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws
964 _M_refcount = __r._M_refcount;
968 __shared_ptr<_Tp, _Lp>
969 lock() const // never throws
972 // Optimization: avoid throw overhead.
974 return __shared_ptr<element_type, _Lp>();
978 return __shared_ptr<element_type, _Lp>(*this);
980 __catch(const bad_weak_ptr&)
982 // Q: How can we get here?
983 // A: Another thread may have invalidated r after the
984 // use_count test above.
985 return __shared_ptr<element_type, _Lp>();
989 // Optimization: avoid try/catch overhead when single threaded.
990 return expired() ? __shared_ptr<element_type, _Lp>()
991 : __shared_ptr<element_type, _Lp>(*this);
997 use_count() const // never throws
998 { return _M_refcount._M_get_use_count(); }
1001 expired() const // never throws
1002 { return _M_refcount._M_get_use_count() == 0; }
1004 template<typename _Tp1>
1006 owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const
1007 { return _M_refcount._M_less(__rhs._M_refcount); }
1009 template<typename _Tp1>
1011 owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const
1012 { return _M_refcount._M_less(__rhs._M_refcount); }
1015 reset() // never throws
1016 { __weak_ptr().swap(*this); }
1019 swap(__weak_ptr& __s) // never throws
1021 std::swap(_M_ptr, __s._M_ptr);
1022 _M_refcount._M_swap(__s._M_refcount);
1026 // Used by __enable_shared_from_this.
1028 _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount)
1031 _M_refcount = __refcount;
1034 template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1035 template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1036 friend class __enable_shared_from_this<_Tp, _Lp>;
1037 friend class enable_shared_from_this<_Tp>;
1039 _Tp* _M_ptr; // Contained pointer.
1040 __weak_count<_Lp> _M_refcount; // Reference counter.
1043 // 20.8.13.3.7 weak_ptr specialized algorithms.
1044 template<typename _Tp, _Lock_policy _Lp>
1046 swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b)
1049 template<typename _Tp, typename _Tp1>
1050 struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool>
1053 operator()(const _Tp& __lhs, const _Tp& __rhs) const
1054 { return __lhs.owner_before(__rhs); }
1057 operator()(const _Tp& __lhs, const _Tp1& __rhs) const
1058 { return __lhs.owner_before(__rhs); }
1061 operator()(const _Tp1& __lhs, const _Tp& __rhs) const
1062 { return __lhs.owner_before(__rhs); }
1065 template<typename _Tp, _Lock_policy _Lp>
1066 struct owner_less<__shared_ptr<_Tp, _Lp>>
1067 : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>
1070 template<typename _Tp, _Lock_policy _Lp>
1071 struct owner_less<__weak_ptr<_Tp, _Lp>>
1072 : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>>
1076 template<typename _Tp, _Lock_policy _Lp>
1077 class __enable_shared_from_this
1080 __enable_shared_from_this() { }
1082 __enable_shared_from_this(const __enable_shared_from_this&) { }
1084 __enable_shared_from_this&
1085 operator=(const __enable_shared_from_this&)
1088 ~__enable_shared_from_this() { }
1091 __shared_ptr<_Tp, _Lp>
1093 { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
1095 __shared_ptr<const _Tp, _Lp>
1096 shared_from_this() const
1097 { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
1100 template<typename _Tp1>
1102 _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const
1103 { _M_weak_this._M_assign(__p, __n); }
1105 template<typename _Tp1>
1107 __enable_shared_from_this_helper(const __shared_count<_Lp>& __pn,
1108 const __enable_shared_from_this* __pe,
1112 __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
1115 mutable __weak_ptr<_Tp, _Lp> _M_weak_this;
1119 template<typename _Tp, _Lock_policy _Lp, typename _Alloc, typename... _Args>
1120 inline __shared_ptr<_Tp, _Lp>
1121 __allocate_shared(_Alloc __a, _Args&&... __args)
1123 return __shared_ptr<_Tp, _Lp>(_Sp_make_shared_tag(),
1124 std::forward<_Alloc>(__a), std::forward<_Args>(__args)...);
1127 template<typename _Tp, _Lock_policy _Lp, typename... _Args>
1128 inline __shared_ptr<_Tp, _Lp>
1129 __make_shared(_Args&&... __args)
1131 typedef typename std::remove_const<_Tp>::type _Tp_nc;
1132 return __allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
1133 std::forward<_Args>(__args)...);
1136 _GLIBCXX_END_NAMESPACE
1138 #endif // _SHARED_PTR_BASE_H