80 lines
1.9 KiB
C++
80 lines
1.9 KiB
C++
#ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED
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#define BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED
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//
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// enable_shared_from_this.hpp
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//
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// Copyright 2002, 2009 Peter Dimov
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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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// http://www.boost.org/libs/smart_ptr/enable_shared_from_this.html
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//
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#include <boost/smart_ptr/weak_ptr.hpp>
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#include <boost/smart_ptr/shared_ptr.hpp>
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#include <boost/assert.hpp>
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#include <boost/config.hpp>
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namespace boost
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{
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template<class T> class enable_shared_from_this
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{
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protected:
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enable_shared_from_this() BOOST_NOEXCEPT
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{
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}
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enable_shared_from_this(enable_shared_from_this const &) BOOST_NOEXCEPT
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{
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}
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enable_shared_from_this & operator=(enable_shared_from_this const &) BOOST_NOEXCEPT
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{
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return *this;
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}
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~enable_shared_from_this() BOOST_NOEXCEPT // ~weak_ptr<T> newer throws, so this call also must not throw
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{
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}
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public:
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shared_ptr<T> shared_from_this()
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{
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shared_ptr<T> p( weak_this_ );
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BOOST_ASSERT( p.get() == this );
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return p;
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}
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shared_ptr<T const> shared_from_this() const
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{
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shared_ptr<T const> p( weak_this_ );
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BOOST_ASSERT( p.get() == this );
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return p;
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}
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public: // actually private, but avoids compiler template friendship issues
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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> const * ppx, Y * py ) const
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{
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if( weak_this_.expired() )
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{
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weak_this_ = shared_ptr<T>( *ppx, py );
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}
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}
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private:
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mutable weak_ptr<T> weak_this_;
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};
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} // namespace boost
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#endif // #ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED
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