| // <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 |