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#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/weak_ptr.htm for documentation.
//
#include <memory> // boost.TR1 include order fix
#include <ndnboost/smart_ptr/detail/shared_count.hpp>
#include <ndnboost/smart_ptr/shared_ptr.hpp>
namespace ndnboost
{
template<class T> class weak_ptr
{
private:
// Borland 5.5.1 specific workarounds
typedef weak_ptr<T> this_type;
public:
typedef typename ndnboost::detail::sp_element< T >::type element_type;
weak_ptr() BOOST_NOEXCEPT : px(0), pn() // never throws in 1.30+
{
}
// 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_NOEXCEPT : px( r.px ), pn( r.pn )
{
}
weak_ptr & operator=( weak_ptr const & r ) BOOST_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) // never throws
// {
// }
//
// 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 ndnboost::detail::sp_enable_if_convertible<Y,T>::type = ndnboost::detail::sp_empty() )
#else
weak_ptr( weak_ptr<Y> const & r )
#endif
BOOST_NOEXCEPT : px(r.lock().get()), pn(r.pn)
{
ndnboost::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 ndnboost::detail::sp_enable_if_convertible<Y,T>::type = ndnboost::detail::sp_empty() )
#else
weak_ptr( weak_ptr<Y> && r )
#endif
BOOST_NOEXCEPT : px( r.lock().get() ), pn( static_cast< ndnboost::detail::weak_count && >( r.pn ) )
{
ndnboost::detail::sp_assert_convertible< Y, T >();
r.px = 0;
}
// for better efficiency in the T == Y case
weak_ptr( weak_ptr && r )
BOOST_NOEXCEPT : px( r.px ), pn( static_cast< ndnboost::detail::weak_count && >( r.pn ) )
{
r.px = 0;
}
// for better efficiency in the T == Y case
weak_ptr & operator=( weak_ptr && r ) BOOST_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 ndnboost::detail::sp_enable_if_convertible<Y,T>::type = ndnboost::detail::sp_empty() )
#else
weak_ptr( shared_ptr<Y> const & r )
#endif
BOOST_NOEXCEPT : px( r.px ), pn( r.pn )
{
ndnboost::detail::sp_assert_convertible< Y, T >();
}
#if !defined(BOOST_MSVC) || (BOOST_MSVC >= 1300)
template<class Y>
weak_ptr & operator=( weak_ptr<Y> const & r ) BOOST_NOEXCEPT
{
ndnboost::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_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_NOEXCEPT
{
ndnboost::detail::sp_assert_convertible< Y, T >();
px = r.px;
pn = r.pn;
return *this;
}
#endif
shared_ptr<T> lock() const BOOST_NOEXCEPT
{
return shared_ptr<T>( *this, ndnboost::detail::sp_nothrow_tag() );
}
long use_count() const BOOST_NOEXCEPT
{
return pn.use_count();
}
bool expired() const BOOST_NOEXCEPT
{
return pn.use_count() == 0;
}
bool _empty() const // extension, not in std::weak_ptr
{
return pn.empty();
}
void reset() BOOST_NOEXCEPT // never throws in 1.30+
{
this_type().swap(*this);
}
void swap(this_type & other) BOOST_NOEXCEPT
{
std::swap(px, other.px);
pn.swap(other.pn);
}
template<typename Y>
void _internal_aliasing_assign(weak_ptr<Y> const & r, element_type * px2)
{
px = px2;
pn = r.pn;
}
template<class Y> bool owner_before( weak_ptr<Y> const & rhs ) const BOOST_NOEXCEPT
{
return pn < rhs.pn;
}
template<class Y> bool owner_before( shared_ptr<Y> const & rhs ) const BOOST_NOEXCEPT
{
return pn < rhs.pn;
}
// 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
ndnboost::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_NOEXCEPT
{
return a.owner_before( b );
}
template<class T> void swap(weak_ptr<T> & a, weak_ptr<T> & b) BOOST_NOEXCEPT
{
a.swap(b);
}
} // namespace ndnboost
#endif // #ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED