Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   attribute_cast.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   06.08.2010
Chris@16:  *
Chris@16:  * The header contains utilities for casting between attribute factories.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/attributes/attribute.hpp>
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace attributes {
Chris@16: 
Chris@16: /*!
Chris@16:  * The class holds a reference to the attribute factory implementation being casted
Chris@16:  */
Chris@16: class cast_source
Chris@16: {
Chris@16: private:
Chris@16:     attribute::impl* m_pImpl;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor. Creates a source that refers to the specified factory implementation.
Chris@16:      */
Chris@16:     explicit cast_source(attribute::impl* p) : m_pImpl(p)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     /*!
Chris@16:      * The function attempts to cast the aggregated pointer to the implementation to the specified type.
Chris@16:      *
Chris@16:      * \return The converted pointer or \c NULL, if the conversion fails.
Chris@16:      */
Chris@16:     template< typename T >
Chris@16:     T* as() const { return dynamic_cast< T* >(m_pImpl); }
Chris@16: };
Chris@16: 
Chris@16: } // namespace attributes
Chris@16: 
Chris@16: /*!
Chris@16:  * The function casts one attribute factory to another
Chris@16:  */
Chris@16: template< typename T >
Chris@16: inline T attribute_cast(attribute const& attr)
Chris@16: {
Chris@16:     return T(attributes::cast_source(attr.get_impl()));
Chris@16: }
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_