145 lines
3.8 KiB
C++
145 lines
3.8 KiB
C++
#ifndef BOOST_ENABLE_SHARED_FROM_RAW_HPP_INCLUDED
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#define BOOST_ENABLE_SHARED_FROM_RAW_HPP_INCLUDED
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//
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// enable_shared_from_raw.hpp
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//
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// Copyright 2002, 2009 Peter Dimov
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// Copyright 2008-2009 Frank Mori Hess
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//
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// Distributed under the Boost Software License, Version 1.0.
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#include <boost/config.hpp>
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#include <boost/shared_ptr.hpp>
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#include <boost/weak_ptr.hpp>
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#include <boost/assert.hpp>
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#include <boost/detail/workaround.hpp>
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namespace boost
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{
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template<typename T> boost::shared_ptr<T> shared_from_raw(T *);
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template<typename T> boost::weak_ptr<T> weak_from_raw(T *);
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namespace detail
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{
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template< class X, class Y > inline void sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe );
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} // namespace detail
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class enable_shared_from_raw
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{
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protected:
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enable_shared_from_raw()
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{
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}
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enable_shared_from_raw( enable_shared_from_raw const & )
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{
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}
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enable_shared_from_raw & operator=( enable_shared_from_raw const & )
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{
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return *this;
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}
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~enable_shared_from_raw()
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{
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BOOST_ASSERT( shared_this_.use_count() <= 1 ); // make sure no dangling shared_ptr objects exist
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}
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private:
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void init_weak_once() const
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{
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if( weak_this_.expired() )
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{
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shared_this_.reset( static_cast<void*>(0), detail::esft2_deleter_wrapper() );
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weak_this_ = shared_this_;
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}
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}
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#ifdef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
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public:
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#else
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private:
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template<class Y> friend class shared_ptr;
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template<typename T> friend boost::shared_ptr<T> shared_from_raw(T *);
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template<typename T> friend boost::weak_ptr<T> weak_from_raw(T *);
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template< class X, class Y > friend inline void detail::sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe );
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#endif
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shared_ptr<void> shared_from_this()
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{
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init_weak_once();
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return shared_ptr<void>( weak_this_ );
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}
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shared_ptr<const void> shared_from_this() const
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{
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init_weak_once();
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return shared_ptr<const void>( weak_this_ );
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}
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// Note: invoked automatically by shared_ptr; do not call
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template<class X, class Y> void _internal_accept_owner( shared_ptr<X> * ppx, Y * py ) const
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{
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BOOST_ASSERT( ppx != 0 );
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if( weak_this_.expired() )
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{
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weak_this_ = *ppx;
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}
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else if( shared_this_.use_count() != 0 )
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{
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BOOST_ASSERT( ppx->unique() ); // no weak_ptrs should exist either, but there's no way to check that
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detail::esft2_deleter_wrapper * pd = boost::get_deleter<detail::esft2_deleter_wrapper>( shared_this_ );
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BOOST_ASSERT( pd != 0 );
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pd->set_deleter( *ppx );
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ppx->reset( shared_this_, ppx->get() );
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shared_this_.reset();
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}
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}
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mutable weak_ptr<void> weak_this_;
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private:
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mutable shared_ptr<void> shared_this_;
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};
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template<typename T>
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boost::shared_ptr<T> shared_from_raw(T *p)
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{
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BOOST_ASSERT(p != 0);
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return boost::shared_ptr<T>(p->enable_shared_from_raw::shared_from_this(), p);
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}
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template<typename T>
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boost::weak_ptr<T> weak_from_raw(T *p)
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{
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BOOST_ASSERT(p != 0);
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boost::weak_ptr<T> result;
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result._internal_aliasing_assign(p->enable_shared_from_raw::weak_this_, p);
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return result;
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}
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namespace detail
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{
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template< class X, class Y > inline void sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe )
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{
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if( pe != 0 )
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{
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pe->_internal_accept_owner( ppx, const_cast< Y* >( py ) );
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}
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}
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} // namepsace detail
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} // namespace boost
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#endif // #ifndef BOOST_ENABLE_SHARED_FROM_RAW_HPP_INCLUDED
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