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Diffstat (limited to 'boost/log/detail/unary_function_terminal.hpp')
-rw-r--r-- | boost/log/detail/unary_function_terminal.hpp | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/boost/log/detail/unary_function_terminal.hpp b/boost/log/detail/unary_function_terminal.hpp new file mode 100644 index 0000000000..f9a3412acf --- /dev/null +++ b/boost/log/detail/unary_function_terminal.hpp @@ -0,0 +1,142 @@ +/* + * Copyright Andrey Semashev 2007 - 2014. + * 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) + */ +/*! + * \file unary_function_terminal.hpp + * \author Andrey Semashev + * \date 21.07.2012 + * + * The header contains attribute value extractor adapter for constructing expression template terminals. + */ + +#ifndef BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_ +#define BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_ + +#include <boost/mpl/bool.hpp> +#include <boost/utility/result_of.hpp> +#include <boost/fusion/sequence/intrinsic/at_c.hpp> +#include <boost/phoenix/core/is_nullary.hpp> +#include <boost/phoenix/core/environment.hpp> +#include <boost/type_traits/remove_cv.hpp> +#include <boost/type_traits/remove_reference.hpp> +#include <boost/log/detail/config.hpp> +#include <boost/log/detail/copy_cv.hpp> +#include <boost/log/detail/custom_terminal_spec.hpp> +#include <boost/log/detail/header.hpp> + +#ifdef BOOST_HAS_PRAGMA_ONCE +#pragma once +#endif + +namespace boost { + +BOOST_LOG_OPEN_NAMESPACE + +namespace expressions { + +namespace aux { + +/*! + * \brief An adapter for a unary function to be used as a terminal in a Boost.Phoenix expression + * + * This class is an adapter between Boost.Phoenix expression invocation protocol and + * a unary function. It forwards the call to the base function, passing only the first argument + * from the original call. This allows to embed value extractors in template expressions. + */ +template< typename FunT > +class unary_function_terminal +{ +private: + //! Adopted function type + typedef FunT function_type; + //! Self type + typedef unary_function_terminal< function_type > this_type; + +public: + //! Internal typedef for type categorization + typedef void _is_boost_log_terminal; + + //! Function result type + template< typename > + struct result; + + template< typename ThisT, typename ContextT > + struct result< ThisT(ContextT) > + { + typedef typename remove_cv< + typename remove_reference< typename phoenix::result_of::env< ContextT >::type >::type + >::type env_type; + typedef typename env_type::args_type args_type; + typedef typename boost::log::aux::copy_cv< ThisT, function_type >::type cv_function_type; + + typedef typename boost::result_of< cv_function_type(typename fusion::result_of::at_c< args_type, 0 >::type) >::type type; + }; + +private: + //! Adopted function + function_type m_fun; + +public: + //! Default constructor + BOOST_DEFAULTED_FUNCTION(unary_function_terminal(), {}) + //! Copy constructor + unary_function_terminal(unary_function_terminal const& that) : m_fun(that.m_fun) {} + //! Initializing constructor + template< typename ArgT1 > + explicit unary_function_terminal(ArgT1 const& arg1) : m_fun(arg1) {} + //! Initializing constructor + template< typename ArgT1, typename ArgT2 > + unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2) : m_fun(arg1, arg2) {} + //! Initializing constructor + template< typename ArgT1, typename ArgT2, typename ArgT3 > + unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2, ArgT3 const& arg3) : m_fun(arg1, arg2, arg3) {} + + //! The operator forwards the call to the base function + template< typename ContextT > + typename result< this_type(ContextT const&) >::type + operator() (ContextT const& ctx) + { + return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args())); + } + + //! The operator forwards the call to the base function + template< typename ContextT > + typename result< const this_type(ContextT const&) >::type + operator() (ContextT const& ctx) const + { + return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args())); + } +}; + +} // namespace aux + +} // namespace expressions + +BOOST_LOG_CLOSE_NAMESPACE // namespace log + +#ifndef BOOST_LOG_DOXYGEN_PASS + +namespace phoenix { + +namespace result_of { + +template< typename FunT > +struct is_nullary< custom_terminal< boost::log::expressions::aux::unary_function_terminal< FunT > > > : + public mpl::false_ +{ +}; + +} // namespace result_of + +} // namespace phoenix + +#endif // BOOST_LOG_DOXYGEN_PASS + +} // namespace boost + +#include <boost/log/detail/footer.hpp> + +#endif // BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_ |