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Diffstat (limited to 'libstdc++-v3/include/tr1/boost_shared_ptr.h')
| -rw-r--r-- | libstdc++-v3/include/tr1/boost_shared_ptr.h | 981 |
1 files changed, 981 insertions, 0 deletions
diff --git a/libstdc++-v3/include/tr1/boost_shared_ptr.h b/libstdc++-v3/include/tr1/boost_shared_ptr.h new file mode 100644 index 00000000000..3426a4acebe --- /dev/null +++ b/libstdc++-v3/include/tr1/boost_shared_ptr.h @@ -0,0 +1,981 @@ +// <tr1/boost_shared_ptr.h> -*- C++ -*- + +// Copyright (C) 2005 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 2, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING. If not, write to the Free +// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, +// USA. + +// As a special exception, you may use this file as part of a free software +// library without restriction. Specifically, if other files instantiate +// templates or use macros or inline functions from this file, or you compile +// this file and link it with other files to produce an executable, this +// file does not by itself cause the resulting executable to be covered by +// the GNU General Public License. This exception does not however +// invalidate any other reasons why the executable file might be covered by +// the GNU General Public License. + +// shared_count.hpp +// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. + +// shared_ptr.hpp +// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes. +// Copyright (C) 2001, 2002, 2003 Peter Dimov + +// weak_ptr.hpp +// Copyright (C) 2001, 2002, 2003 Peter Dimov + +// enable_shared_from_this.hpp +// Copyright (C) 2002 Peter Dimov + +// Distributed under the Boost Software License, Version 1.0. (See +// accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) + +// GCC Note: based on version 1.32.0 of the Boost library. + +/** @file boost_memory.h + * This is an internal header file, included by other library headers. + * You should not attempt to use it directly. + */ + +#ifndef _BOOST_SHARED_PTR_H +#define _BOOST_SHARED_PTR_H 1 + +// namespace std::tr1 +namespace std +{ +namespace tr1 +{ + +class bad_weak_ptr : public std::exception +{ +public: + + virtual char const* what() const throw() + { + return "tr1::bad_weak_ptr"; + } +}; + +// Helper for exception objects in <tr1/memory> +// TODO this should be defined in a different file. +inline void +__throw_bad_weak_ptr() +{ +#if __EXCEPTIONS + throw bad_weak_ptr(); +#else + std::abort(); +#endif +} + + +template <typename _Tp> + struct _Sp_deleter + { + typedef void result_type; + typedef _Tp* argument_type; + + void + operator()(_Tp* p) const + { delete p; } + }; + + +class _Sp_counted_base +{ +public: + + _Sp_counted_base() + : _M_use_count(1), _M_weak_count(1) + { } + + virtual + ~_Sp_counted_base() // nothrow + { } + + // dispose() is called when _M_use_count drops to zero, to release + // the resources managed by *this. + virtual void + dispose() = 0; // nothrow + + // destroy() is called when _M_weak_count drops to zero. + virtual void + destroy() // nothrow + { + delete this; + } + + virtual void* + get_deleter(const std::type_info&) = 0; + + void + add_ref_copy() + { + __gnu_cxx::__atomic_add(&_M_use_count, 1); + } + + void + add_ref_lock() + { + __gnu_cxx::lock lock(_M_mutex); + if (__gnu_cxx::__exchange_and_add(&_M_use_count, 1) == 0) + { + _M_use_count = 0; + __throw_bad_weak_ptr(); + } + } + + void + release() // nothrow + { + if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) == 1) + { + dispose(); + __glibcxx_mutex_lock(_M_mutex); + __glibcxx_mutex_unlock(_M_mutex); + weak_release(); + } + } + + void + weak_add_ref() // nothrow + { + __gnu_cxx::__atomic_add(&_M_weak_count, 1); + } + + void + weak_release() // nothrow + { + if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) == 1) + { + __glibcxx_mutex_lock(_M_mutex); + __glibcxx_mutex_unlock(_M_mutex); + destroy(); + } + } + + long + use_count() const // nothrow + { + return _M_use_count; // XXX is this MT safe? + } + +private: + + _Sp_counted_base(_Sp_counted_base const&); + _Sp_counted_base& operator= (_Sp_counted_base const&); + + _Atomic_word _M_use_count; // #shared + _Atomic_word _M_weak_count; // #weak + (#shared != 0) + __gnu_cxx::mutex_type _M_mutex; +}; + +template <typename _Ptr, typename _Deleter> +class _Sp_counted_base_impl : public _Sp_counted_base +{ +public: + + /** + * @brief + * @pre d(p) must not throw. + */ + _Sp_counted_base_impl(_Ptr __p, _Deleter __d) + : _M_ptr(__p), _M_del(__d) + { } + + virtual void + dispose() // nothrow + { + _M_del(_M_ptr); + } + + virtual void* + get_deleter(const std::type_info& __ti) + { + return __ti == typeid(_Deleter) ? &_M_del : 0; + } + +private: + _Sp_counted_base_impl(const _Sp_counted_base_impl&); + _Sp_counted_base_impl& operator=(const _Sp_counted_base_impl&); + + _Ptr _M_ptr; // copy constructor must not throw + _Deleter _M_del; // copy constructor must not throw +}; + +class weak_count; + +class shared_count +{ +private: + + _Sp_counted_base* _M_pi; + + friend class weak_count; + +public: + + shared_count() + : _M_pi(0) // nothrow + { } + + template <typename _Ptr, typename _Deleter> + shared_count(_Ptr __p, _Deleter __d) + : _M_pi(0) + { + try + { + _M_pi = new _Sp_counted_base_impl<_Ptr, _Deleter>(__p, __d); + } + catch(...) + { + __d(__p); // delete __p + __throw_exception_again; + } + } + + // auto_ptr<_Tp> is special cased to provide the strong guarantee + + template <typename _Tp> + explicit shared_count(std::auto_ptr<_Tp>& __r) + : _M_pi(new _Sp_counted_base_impl<_Tp*,_Sp_deleter<_Tp> >( + __r.get(), _Sp_deleter<_Tp>() + )) + { __r.release(); } + + // throws bad_weak_ptr when __r.use_count() == 0 + explicit shared_count(const weak_count& __r); + + ~shared_count() // nothrow + { + if (_M_pi != 0) + _M_pi->release(); + } + + shared_count(const shared_count& __r) + : _M_pi(__r._M_pi) // nothrow + { + if (_M_pi != 0) + _M_pi->add_ref_copy(); + } + + shared_count& + operator=(const shared_count& __r) // nothrow + { + _Sp_counted_base* __tmp = __r._M_pi; + + if(__tmp != _M_pi) + { + if(__tmp != 0) + __tmp->add_ref_copy(); + if(_M_pi != 0) + _M_pi->release(); + _M_pi = __tmp; + } + return *this; + } + + void swap(shared_count& __r) // nothrow + { + _Sp_counted_base* __tmp = __r._M_pi; + __r._M_pi = _M_pi; + _M_pi = __tmp; + } + + long + use_count() const // nothrow + { return _M_pi != 0 ? _M_pi->use_count() : 0; } + + bool + unique() const // nothrow + { return this->use_count() == 1; } + + friend inline bool + operator==(const shared_count& __a, const shared_count& __b) + { return __a._M_pi == __b._M_pi; } + + friend inline bool + operator<(const shared_count& __a, const shared_count& __b) + { return std::less<_Sp_counted_base*>()(__a._M_pi, __b._M_pi); } + + void* + get_deleter(const std::type_info& __ti) const + { return _M_pi ? _M_pi->get_deleter(__ti) : 0; } +}; + + +class weak_count +{ +private: + + _Sp_counted_base * _M_pi; + + friend class shared_count; + +public: + + weak_count() + : _M_pi(0) // nothrow + { } + + weak_count(const shared_count& __r) + : _M_pi(__r._M_pi) // nothrow + { + if (_M_pi != 0) + _M_pi->weak_add_ref(); + } + + weak_count(const weak_count& __r) + : _M_pi(__r._M_pi) // nothrow + { + if (_M_pi != 0) + _M_pi->weak_add_ref(); + } + + ~weak_count() // nothrow + { + if (_M_pi != 0) + _M_pi->weak_release(); + } + + weak_count& + operator=(const shared_count& __r) // nothrow + { + _Sp_counted_base* __tmp = __r._M_pi; + if (__tmp != 0) + __tmp->weak_add_ref(); + if (_M_pi != 0) + _M_pi->weak_release(); + _M_pi = __tmp; + + return *this; + } + + weak_count& + operator=(const weak_count& __r) // nothrow + { + _Sp_counted_base * __tmp = __r._M_pi; + if (__tmp != 0) + __tmp->weak_add_ref(); + if (_M_pi != 0) + _M_pi->weak_release(); + _M_pi = __tmp; + + return *this; + } + + void + swap(weak_count& __r) // nothrow + { + _Sp_counted_base * __tmp = __r._M_pi; + __r._M_pi = _M_pi; + _M_pi = __tmp; + } + + long + use_count() const // nothrow + { return _M_pi != 0 ? _M_pi->use_count() : 0; } + + friend inline bool + operator==(const weak_count& __a, const weak_count& __b) + { return __a._M_pi == __b._M_pi; } + + friend inline bool + operator<(const weak_count& __a, const weak_count& __b) + { return std::less<_Sp_counted_base*>()(__a._M_pi, __b._M_pi); } +}; + +inline +shared_count::shared_count(const weak_count& __r) +: _M_pi(__r._M_pi) +{ + if (_M_pi != 0) + { + _M_pi->add_ref_lock(); + } + else + { + __throw_bad_weak_ptr(); + } +} + +// fwd decls +template <typename _Tp> class weak_ptr; +template <typename _Tp> class enable_shared_from_this; + +struct __static_cast_tag {}; +struct __const_cast_tag {}; +struct __dynamic_cast_tag {}; +struct __polymorphic_cast_tag {}; + +template<class _Tp> struct shared_ptr_traits +{ + typedef _Tp & reference; +}; + +template<> struct shared_ptr_traits<void> +{ + typedef void reference; +}; + +template<> struct shared_ptr_traits<void const> +{ + typedef void reference; +}; + +template<> struct shared_ptr_traits<void volatile> +{ + typedef void reference; +}; + +template<> struct shared_ptr_traits<void const volatile> +{ + typedef void reference; +}; + + +// enable_shared_from_this support + +// friend of enable_shared_from_this +template <typename _Tp1, typename _Tp2> + void + __enable_shared_from_this( const shared_count& __pn, + const enable_shared_from_this<_Tp1>* __pe, + const _Tp2* __px ); + +inline void +__enable_shared_from_this(const shared_count&, ...) +{ } + +/** + * @class shared_ptr <tr1/memory> + * + * A smart pointer with reference-counted copy semantics. + * The object pointed to is deleted when the last shared_ptr pointing to it + * is destroyed or reset. + */ + +template <typename _Tp> + class shared_ptr + { + typedef typename shared_ptr_traits<_Tp>::reference _Reference; + + public: + + typedef _Tp element_type; + + /** @brief Construct an empty %shared_ptr. + * @post use_count()==0 && get()==0 + */ + shared_ptr() : _M_ptr(0), _M_refcount() // never throws + { } + + /** @brief Construct a %shared_ptr that owns the pointer @a p. + * @param p A pointer that is convertible to element_type*. + * @post use_count()==1 && get()==p + * @throw std::bad_alloc, in which case @c delete @a p is called. + */ + template <typename _Tp1> + explicit shared_ptr(_Tp1* __p) + : _M_ptr(__p), _M_refcount(__p, _Sp_deleter<_Tp1>()) + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + // __glibcxx_function_requires(_CompleteConcept<_Tp1*>) + + __enable_shared_from_this( _M_refcount, __p, __p ); + } + + // + // Requirements: D's copy constructor and destructor must not throw + // + // shared_ptr will release p by calling d(p) + // + /** @brief Construct a %shared_ptr that owns the pointer @a p + * and the deleter @a d. + * @param p A pointer. + * @param d A deleter. + * @post use_count()==1 && get()==p + * @throw std::bad_alloc, in which case @a d(p) is called. + */ + template <typename _Tp1, typename _Deleter> + shared_ptr(_Tp1* __p, _Deleter __d) + : _M_ptr(__p), _M_refcount(__p, __d) + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + // TODO requires D is CopyConstructible and d(p) well-formed + + __enable_shared_from_this( _M_refcount, __p, __p ); + } + + // generated copy constructor, assignment, destructor are fine. + + /** @brief If @a r is empty, constructs an empty %shared_ptr; otherwise + * construct a %shared_ptr that shares ownership with @a r. + * @param r A %shared_ptr. + * @post get()==r.get() && use_count()==r.use_count() + * @throw std::bad_alloc, in which case + */ + template <typename _Tp1> + shared_ptr(const shared_ptr<_Tp1>& __r) + : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + } + + /** @brief Constructs a %shared_ptr that shares ownership with @a r + * and stores a copy of the pointer stored in @a r. + * @param r A weak_ptr. + * @post use_count()==r.use_count() + * @throw bad_weak_ptr when r.expired(), + * in which case the constructor has no effect. + */ + template <typename _Tp1> + explicit shared_ptr(const weak_ptr<_Tp1>& __r) + : _M_refcount(__r._M_refcount) // may throw + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + // it is now safe to copy r__._M_ptr, as _M_refcount(__r._M_refcount) + // did not throw + _M_ptr = __r._M_ptr; + } + + /** + * @post use_count()==1 and r.get()==0 + */ + template <typename _Tp1> + explicit shared_ptr(std::auto_ptr<_Tp1>& __r) + : _M_ptr(__r.get()), _M_refcount() + { + // TODO requires r.release() convertible to _Tp*, Tp1 is complete, + // delete r.release() well-formed + _Tp1 * __tmp = __r.get(); + _M_refcount = shared_count(__r); + + __enable_shared_from_this( _M_refcount, __tmp, __tmp ); + } + + template <typename _Tp1> + shared_ptr(const shared_ptr<_Tp1>& __r, __static_cast_tag) + : _M_ptr(static_cast<element_type*>(__r._M_ptr)) + , _M_refcount(__r._M_refcount) + { } + + template <typename _Tp1> + shared_ptr(const shared_ptr<_Tp1>& __r, __const_cast_tag) + : _M_ptr(const_cast<element_type*>(__r._M_ptr)) + , _M_refcount(__r._M_refcount) + { } + + template <typename _Tp1> + shared_ptr(const shared_ptr<_Tp1>& __r, __dynamic_cast_tag) + : _M_ptr(dynamic_cast<element_type*>(__r._M_ptr)) + , _M_refcount(__r._M_refcount) + { + if (_M_ptr == 0) // need to allocate new counter -- the cast failed + { + _M_refcount = shared_count(); + } + } + + template <typename _Tp1> + shared_ptr& + operator=(const shared_ptr<_Tp1>& __r) // never throws + { + _M_ptr = __r._M_ptr; + _M_refcount = __r._M_refcount; // shared_count::op= doesn't throw + return *this; + } + + template <typename _Tp1> + shared_ptr& + operator=(std::auto_ptr<_Tp1>& __r) + { + shared_ptr(__r).swap(*this); + return *this; + } + + void + reset() // never throws + { shared_ptr().swap(*this); } + + template <typename _Tp1> + void + reset(_Tp1* __p) // _Tp1 must be complete + { + _GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr); // catch self-reset errors + shared_ptr(__p).swap(*this); + } + + template <typename _Tp1, typename _Deleter> + void + reset(_Tp1 * __p, _Deleter __d) + { shared_ptr(__p, __d).swap(*this); } + + // error to instantiate if _Tp is [cv-qual] void + _Reference + operator*() const // never throws + { + _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); + return *_M_ptr; + } + + _Tp* + operator->() const // never throws + { + _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); + return _M_ptr; + } + + _Tp* + get() const // never throws + { return _M_ptr; } + + // implicit conversion to "bool" + private: + typedef _Tp* shared_ptr::*__unspecified_bool_type; + + public: + operator __unspecified_bool_type() const // never throws + { return _M_ptr == 0 ? 0 : &shared_ptr::_M_ptr; } + + bool + unique() const // never throws + { return _M_refcount.unique(); } + + long + use_count() const // never throws + { return _M_refcount.use_count(); } + + void + swap(shared_ptr<_Tp>& __other) // never throws + { + std::swap(_M_ptr, __other._M_ptr); + _M_refcount.swap(__other._M_refcount); + } + + private: + template <typename _Tp1> + bool + _M_less(const shared_ptr<_Tp1>& __rhs) const + { return _M_refcount < __rhs._M_refcount; } + + void* + _M_get_deleter(const std::type_info& __ti) const + { return _M_refcount.get_deleter(__ti); } + + template <typename _Tp1> friend class shared_ptr; + template <typename _Tp1> friend class weak_ptr; + + // friends injected into enclosing namespace and found by ADL: + + // get_deleter (experimental) + template <typename _Del> + friend inline _Del* + get_deleter(const shared_ptr& __p) + { return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); } + + template <typename _Tp1> + friend inline bool + operator==(const shared_ptr& __a, const shared_ptr<_Tp1>& __b) + { return __a.get() == __b.get(); } + + template <typename _Tp1> + friend inline bool + operator!=(const shared_ptr& __a, const shared_ptr<_Tp1>& __b) + { return __a.get() != __b.get(); } + + template <typename _Tp1> + friend inline bool + operator<(const shared_ptr& __a, const shared_ptr<_Tp1>& __b) + { return __a._M_less(__b); } + + _Tp* _M_ptr; // contained pointer + shared_count _M_refcount; // reference counter + }; // shared_ptr + +// 2.2.3.9 shared_ptr casts + +/** @warning The seemingly equivalent + * <code>shared_ptr<T>(static_cast<T*>(r.get()))</code> + * will eventually result in undefined behaviour, + * attempting to delete the same object twice. + */ +template <typename _Tp, typename _Tp1> + shared_ptr<_Tp> + static_pointer_cast(const shared_ptr<_Tp1>& __r) + { + return shared_ptr<_Tp>(__r, __static_cast_tag()); + } + +/** @warning The seemingly equivalent + * <code>shared_ptr<T>(const_cast<T*>(r.get()))</code> + * will eventually result in undefined behaviour, + * attempting to delete the same object twice. + */ +template <typename _Tp, typename _Tp1> + shared_ptr<_Tp> + const_pointer_cast(const shared_ptr<_Tp1>& __r) + { + return shared_ptr<_Tp>(__r, __const_cast_tag()); + } + +/** @warning The seemingly equivalent + * <code>shared_ptr<T>(dynamic_cast<T*>(r.get()))</code> + * will eventually result in undefined behaviour, + * attempting to delete the same object twice. + */ +template <typename _Tp, typename _Tp1> + shared_ptr<_Tp> + dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) + { + return shared_ptr<_Tp>(__r, __dynamic_cast_tag()); + } + +// operator<< +template <typename _Ch, typename _Tr, typename _Tp> + std::basic_ostream<_Ch,_Tr>& + operator<<(std::basic_ostream<_Ch,_Tr>& __os, const shared_ptr<_Tp>& __p) + { + __os << __p.get(); + return __os; + } + + +template <typename _Tp> + class weak_ptr + { + public: + + typedef _Tp element_type; + + weak_ptr() + : _M_ptr(0), _M_refcount() // never throws + { } + + // generated copy constructor, assignment, destructor are fine + + // + // The "obvious" converting constructor implementation: + // + // template<class Y> + // weak_ptr(weak_ptr<Y> const & r): _M_ptr(r._M_ptr), _M_refcount(r._M_refcount) // never throws + // { + // } + // + // has a serious problem. + // + // r._M_ptr may already have been invalidated. The _M_ptr(r._M_ptr) + // conversion may require access to *r._M_ptr (virtual inheritance). + // + // It is not possible to avoid spurious access violations since + // in multithreaded programs r._M_ptr may be invalidated at any point. + // + + template <typename _Tp1> + weak_ptr(const weak_ptr<_Tp1>& r) + : _M_refcount(r._M_refcount) // never throws + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + _M_ptr = r.lock().get(); + } + + template <typename _Tp1> + weak_ptr(const shared_ptr<_Tp1>& r) + : _M_ptr(r._M_ptr), _M_refcount(r._M_refcount) // never throws + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + } + + template <typename _Tp1> + weak_ptr& + operator=(const weak_ptr<_Tp1>& r) // never throws + { + _M_ptr = r.lock().get(); + _M_refcount = r._M_refcount; + return *this; + } + + template <typename _Tp1> + weak_ptr& + operator=(const shared_ptr<_Tp1>& r) // never throws + { + _M_ptr = r._M_ptr; + _M_refcount = r._M_refcount; + return *this; + } + + shared_ptr<_Tp> + lock() const // never throws + { +#ifdef __GTHREADS + + // optimization: avoid throw overhead + if (expired()) + { + return shared_ptr<element_type>(); + } + + try + { + return shared_ptr<element_type>(*this); + } + catch (const bad_weak_ptr&) + { + // Q: how can we get here? + // A: another thread may have invalidated r after the use_count test above. + return shared_ptr<element_type>(); + } + +#else + + // optimization: avoid try/catch overhead when single threaded + return expired() ? shared_ptr<element_type>() : shared_ptr<element_type>(*this); + +#endif + } // XXX MT + + + long + use_count() const // never throws + { return _M_refcount.use_count(); } + + bool + expired() const // never throws + { return _M_refcount.use_count() == 0; } + + void + reset() // never throws + { weak_ptr().swap(*this); } + + void + swap(weak_ptr& __s) // never throws + { + std::swap(_M_ptr, __s._M_ptr); + _M_refcount.swap(__s._M_refcount); + } + + private: + + template <typename _Tp1> + bool + _M_less(const weak_ptr<_Tp1>& __rhs) const + { return _M_refcount < __rhs._M_refcount; } + + // used by __enable_shared_from_this + void + _M_assign(_Tp* __ptr, const shared_count& __refcount) + { + _M_ptr = __ptr; + _M_refcount = __refcount; + } + + // friend injected into namespace and found by ADL + + template <typename _Tp1> + friend inline bool + operator<(const weak_ptr& __lhs, const weak_ptr<_Tp1>& __rhs) + { return __lhs._M_less(__rhs); } + + template <typename _Tp1> friend class weak_ptr; + template <typename _Tp1> friend class shared_ptr; + friend class enable_shared_from_this<_Tp>; + + _Tp* _M_ptr; // contained pointer + weak_count _M_refcount; // reference counter + + }; // weak_ptr + + + +template <typename _Tp> + class enable_shared_from_this + { + protected: + + enable_shared_from_this() + { } + + enable_shared_from_this(const enable_shared_from_this&) + { } + + enable_shared_from_this& + operator=(const enable_shared_from_this&) + { return *this; } + + ~enable_shared_from_this() + { } + + public: + + shared_ptr<_Tp> + shared_from_this() + { + shared_ptr<_Tp> p(this->_M_weak_this); + return p; + } + + shared_ptr<const _Tp> + shared_from_this() const + { + shared_ptr<const _Tp> p(this->_M_weak_this); + return p; + } + + private: + template <typename _Tp1> + void + _M_weak_assign(_Tp1* __p, const shared_count& __n) const + { _M_weak_this._M_assign(__p, __n); } + + template <typename _Tp1> + friend void + __enable_shared_from_this( const shared_count& __pn, const enable_shared_from_this* __pe, const _Tp1* __px) + { + if(__pe != 0) + __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn); + } + + mutable weak_ptr<_Tp> _M_weak_this; + }; + +} // namespace tr1 + +/** + * @brief std::swap() specialisation for shared_ptr. + * @relates shared_ptr. + */ +template <typename _Tp> + inline void + swap(tr1::shared_ptr<_Tp>& __a, tr1::shared_ptr<_Tp>& __b) + { + __a.swap(__b); + } + +/** + * @brief std::swap() specialisation for weak_ptr. + * @relates weak_ptr. + */ +template <typename _Tp> + void + swap(tr1::weak_ptr<_Tp>& __a, tr1::weak_ptr<_Tp>& __b) + { + __a.swap(__b); + } + +} // namespace std + +#endif |