| #ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED |
| #define BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED |
| |
| // |
| // weak_ptr.hpp |
| // |
| // Copyright (c) 2001, 2002, 2003 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) |
| // |
| // See http://www.boost.org/libs/smart_ptr/ for documentation. |
| // |
| |
| #include <boost/smart_ptr/detail/shared_count.hpp> |
| #include <boost/smart_ptr/shared_ptr.hpp> |
| #include <boost/smart_ptr/detail/sp_noexcept.hpp> |
| #include <memory> |
| #include <cstddef> |
| |
| namespace boost |
| { |
| |
| template<class T> class weak_ptr |
| { |
| private: |
| |
| // Borland 5.5.1 specific workarounds |
| typedef weak_ptr<T> this_type; |
| |
| public: |
| |
| typedef typename boost::detail::sp_element< T >::type element_type; |
| |
| BOOST_CONSTEXPR weak_ptr() BOOST_SP_NOEXCEPT : px(0), pn() |
| { |
| } |
| |
| // generated copy constructor, assignment, destructor are fine... |
| |
| #if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES ) |
| |
| // ... except in C++0x, move disables the implicit copy |
| |
| weak_ptr( weak_ptr const & r ) BOOST_SP_NOEXCEPT : px( r.px ), pn( r.pn ) |
| { |
| } |
| |
| weak_ptr & operator=( weak_ptr const & r ) BOOST_SP_NOEXCEPT |
| { |
| px = r.px; |
| pn = r.pn; |
| return *this; |
| } |
| |
| #endif |
| |
| // |
| // The "obvious" converting constructor implementation: |
| // |
| // template<class Y> |
| // weak_ptr(weak_ptr<Y> const & r): px(r.px), pn(r.pn) |
| // { |
| // } |
| // |
| // has a serious problem. |
| // |
| // r.px may already have been invalidated. The px(r.px) |
| // conversion may require access to *r.px (virtual inheritance). |
| // |
| // It is not possible to avoid spurious access violations since |
| // in multithreaded programs r.px may be invalidated at any point. |
| // |
| |
| template<class Y> |
| #if !defined( BOOST_SP_NO_SP_CONVERTIBLE ) |
| |
| weak_ptr( weak_ptr<Y> const & r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() ) |
| |
| #else |
| |
| weak_ptr( weak_ptr<Y> const & r ) |
| |
| #endif |
| BOOST_SP_NOEXCEPT : px(r.lock().get()), pn(r.pn) |
| { |
| boost::detail::sp_assert_convertible< Y, T >(); |
| } |
| |
| #if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES ) |
| |
| template<class Y> |
| #if !defined( BOOST_SP_NO_SP_CONVERTIBLE ) |
| |
| weak_ptr( weak_ptr<Y> && r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() ) |
| |
| #else |
| |
| weak_ptr( weak_ptr<Y> && r ) |
| |
| #endif |
| BOOST_SP_NOEXCEPT : px( r.lock().get() ), pn( static_cast< boost::detail::weak_count && >( r.pn ) ) |
| { |
| boost::detail::sp_assert_convertible< Y, T >(); |
| r.px = 0; |
| } |
| |
| // for better efficiency in the T == Y case |
| weak_ptr( weak_ptr && r ) |
| BOOST_SP_NOEXCEPT : px( r.px ), pn( static_cast< boost::detail::weak_count && >( r.pn ) ) |
| { |
| r.px = 0; |
| } |
| |
| // for better efficiency in the T == Y case |
| weak_ptr & operator=( weak_ptr && r ) BOOST_SP_NOEXCEPT |
| { |
| this_type( static_cast< weak_ptr && >( r ) ).swap( *this ); |
| return *this; |
| } |
| |
| |
| #endif |
| |
| template<class Y> |
| #if !defined( BOOST_SP_NO_SP_CONVERTIBLE ) |
| |
| weak_ptr( shared_ptr<Y> const & r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() ) |
| |
| #else |
| |
| weak_ptr( shared_ptr<Y> const & r ) |
| |
| #endif |
| BOOST_SP_NOEXCEPT : px( r.px ), pn( r.pn ) |
| { |
| boost::detail::sp_assert_convertible< Y, T >(); |
| } |
| |
| // aliasing |
| template<class Y> weak_ptr(shared_ptr<Y> const & r, element_type * p) BOOST_SP_NOEXCEPT: px( p ), pn( r.pn ) |
| { |
| } |
| |
| template<class Y> weak_ptr(weak_ptr<Y> const & r, element_type * p) BOOST_SP_NOEXCEPT: px( p ), pn( r.pn ) |
| { |
| } |
| |
| #if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES ) |
| |
| template<class Y> weak_ptr(weak_ptr<Y> && r, element_type * p) BOOST_SP_NOEXCEPT: px( p ), pn( std::move( r.pn ) ) |
| { |
| } |
| |
| #endif |
| |
| #if !defined(BOOST_MSVC) || (BOOST_MSVC >= 1300) |
| |
| template<class Y> |
| weak_ptr & operator=( weak_ptr<Y> const & r ) BOOST_SP_NOEXCEPT |
| { |
| boost::detail::sp_assert_convertible< Y, T >(); |
| |
| px = r.lock().get(); |
| pn = r.pn; |
| |
| return *this; |
| } |
| |
| #if !defined( BOOST_NO_CXX11_RVALUE_REFERENCES ) |
| |
| template<class Y> |
| weak_ptr & operator=( weak_ptr<Y> && r ) BOOST_SP_NOEXCEPT |
| { |
| this_type( static_cast< weak_ptr<Y> && >( r ) ).swap( *this ); |
| return *this; |
| } |
| |
| #endif |
| |
| template<class Y> |
| weak_ptr & operator=( shared_ptr<Y> const & r ) BOOST_SP_NOEXCEPT |
| { |
| boost::detail::sp_assert_convertible< Y, T >(); |
| |
| px = r.px; |
| pn = r.pn; |
| |
| return *this; |
| } |
| |
| #endif |
| |
| shared_ptr<T> lock() const BOOST_SP_NOEXCEPT |
| { |
| return shared_ptr<T>( *this, boost::detail::sp_nothrow_tag() ); |
| } |
| |
| long use_count() const BOOST_SP_NOEXCEPT |
| { |
| return pn.use_count(); |
| } |
| |
| bool expired() const BOOST_SP_NOEXCEPT |
| { |
| return pn.use_count() == 0; |
| } |
| |
| bool _empty() const BOOST_SP_NOEXCEPT // extension, not in std::weak_ptr |
| { |
| return pn.empty(); |
| } |
| |
| bool empty() const BOOST_SP_NOEXCEPT // extension, not in std::weak_ptr |
| { |
| return pn.empty(); |
| } |
| |
| void reset() BOOST_SP_NOEXCEPT |
| { |
| this_type().swap(*this); |
| } |
| |
| void swap(this_type & other) BOOST_SP_NOEXCEPT |
| { |
| std::swap(px, other.px); |
| pn.swap(other.pn); |
| } |
| |
| template<class Y> bool owner_before( weak_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT |
| { |
| return pn < rhs.pn; |
| } |
| |
| template<class Y> bool owner_before( shared_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT |
| { |
| return pn < rhs.pn; |
| } |
| |
| template<class Y> bool owner_equals( weak_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT |
| { |
| return pn == rhs.pn; |
| } |
| |
| template<class Y> bool owner_equals( shared_ptr<Y> const & rhs ) const BOOST_SP_NOEXCEPT |
| { |
| return pn == rhs.pn; |
| } |
| |
| std::size_t owner_hash_value() const BOOST_SP_NOEXCEPT |
| { |
| return pn.hash_value(); |
| } |
| |
| // Tasteless as this may seem, making all members public allows member templates |
| // to work in the absence of member template friends. (Matthew Langston) |
| |
| #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS |
| |
| private: |
| |
| template<class Y> friend class weak_ptr; |
| template<class Y> friend class shared_ptr; |
| |
| #endif |
| |
| element_type * px; // contained pointer |
| boost::detail::weak_count pn; // reference counter |
| |
| }; // weak_ptr |
| |
| template<class T, class U> inline bool operator<(weak_ptr<T> const & a, weak_ptr<U> const & b) BOOST_SP_NOEXCEPT |
| { |
| return a.owner_before( b ); |
| } |
| |
| template<class T> void swap(weak_ptr<T> & a, weak_ptr<T> & b) BOOST_SP_NOEXCEPT |
| { |
| a.swap(b); |
| } |
| |
| #if defined(__cpp_deduction_guides) |
| |
| template<class T> weak_ptr( shared_ptr<T> ) -> weak_ptr<T>; |
| |
| #endif |
| |
| // hash_value |
| |
| template< class T > std::size_t hash_value( boost::weak_ptr<T> const & p ) BOOST_SP_NOEXCEPT |
| { |
| return p.owner_hash_value(); |
| } |
| |
| } // namespace boost |
| |
| // std::hash, std::equal_to |
| |
| namespace std |
| { |
| |
| #if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL) |
| |
| template<class T> struct hash< ::boost::weak_ptr<T> > |
| { |
| std::size_t operator()( ::boost::weak_ptr<T> const & p ) const BOOST_SP_NOEXCEPT |
| { |
| return p.owner_hash_value(); |
| } |
| }; |
| |
| #endif // #if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL) |
| |
| template<class T> struct equal_to< ::boost::weak_ptr<T> > |
| { |
| bool operator()( ::boost::weak_ptr<T> const & a, ::boost::weak_ptr<T> const & b ) const BOOST_SP_NOEXCEPT |
| { |
| return a.owner_equals( b ); |
| } |
| }; |
| |
| } // namespace std |
| |
| #endif // #ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED |