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   unary_function_terminal.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   21.07.2012
Chris@16:  *
Chris@16:  * The header contains attribute value extractor adapter for constructing expression template terminals.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/utility/result_of.hpp>
Chris@16: #include <boost/fusion/sequence/intrinsic/at_c.hpp>
Chris@16: #include <boost/phoenix/core/is_nullary.hpp>
Chris@16: #include <boost/phoenix/core/environment.hpp>
Chris@16: #include <boost/type_traits/remove_cv.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@101: #include <boost/log/detail/copy_cv.hpp>
Chris@16: #include <boost/log/detail/custom_terminal_spec.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 expressions {
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief An adapter for a unary function to be used as a terminal in a Boost.Phoenix expression
Chris@16:  *
Chris@16:  * This class is an adapter between Boost.Phoenix expression invocation protocol and
Chris@16:  * a unary function. It forwards the call to the base function, passing only the first argument
Chris@16:  * from the original call. This allows to embed value extractors in template expressions.
Chris@16:  */
Chris@16: template< typename FunT >
Chris@16: class unary_function_terminal
Chris@16: {
Chris@16: private:
Chris@16:     //! Adopted function type
Chris@16:     typedef FunT function_type;
Chris@16:     //! Self type
Chris@16:     typedef unary_function_terminal< function_type > this_type;
Chris@16: 
Chris@16: public:
Chris@16:     //! Internal typedef for type categorization
Chris@16:     typedef void _is_boost_log_terminal;
Chris@16: 
Chris@16:     //! Function result type
Chris@16:     template< typename >
Chris@16:     struct result;
Chris@16: 
Chris@101:     template< typename ThisT, typename ContextT >
Chris@101:     struct result< ThisT(ContextT) >
Chris@16:     {
Chris@16:         typedef typename remove_cv<
Chris@16:             typename remove_reference< typename phoenix::result_of::env< ContextT >::type >::type
Chris@16:         >::type env_type;
Chris@16:         typedef typename env_type::args_type args_type;
Chris@101:         typedef typename boost::log::aux::copy_cv< ThisT, function_type >::type cv_function_type;
Chris@16: 
Chris@101:         typedef typename boost::result_of< cv_function_type(typename fusion::result_of::at_c< args_type, 0 >::type) >::type type;
Chris@16:     };
Chris@16: 
Chris@16: private:
Chris@16:     //! Adopted function
Chris@16:     function_type m_fun;
Chris@16: 
Chris@16: public:
Chris@16:     //! Default constructor
Chris@16:     BOOST_DEFAULTED_FUNCTION(unary_function_terminal(), {})
Chris@16:     //! Copy constructor
Chris@16:     unary_function_terminal(unary_function_terminal const& that) : m_fun(that.m_fun) {}
Chris@16:     //! Initializing constructor
Chris@16:     template< typename ArgT1 >
Chris@16:     explicit unary_function_terminal(ArgT1 const& arg1) : m_fun(arg1) {}
Chris@16:     //! Initializing constructor
Chris@16:     template< typename ArgT1, typename ArgT2 >
Chris@16:     unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2) : m_fun(arg1, arg2) {}
Chris@16:     //! Initializing constructor
Chris@16:     template< typename ArgT1, typename ArgT2, typename ArgT3 >
Chris@16:     unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2, ArgT3 const& arg3) : m_fun(arg1, arg2, arg3) {}
Chris@16: 
Chris@16:     //! The operator forwards the call to the base function
Chris@16:     template< typename ContextT >
Chris@16:     typename result< this_type(ContextT const&) >::type
Chris@16:     operator() (ContextT const& ctx)
Chris@16:     {
Chris@16:         return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args()));
Chris@16:     }
Chris@16: 
Chris@16:     //! The operator forwards the call to the base function
Chris@16:     template< typename ContextT >
Chris@16:     typename result< const this_type(ContextT const&) >::type
Chris@16:     operator() (ContextT const& ctx) const
Chris@16:     {
Chris@16:         return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args()));
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } // namespace aux
Chris@16: 
Chris@16: } // namespace expressions
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: #ifndef BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: namespace phoenix {
Chris@16: 
Chris@16: namespace result_of {
Chris@16: 
Chris@16: template< typename FunT >
Chris@16: struct is_nullary< custom_terminal< boost::log::expressions::aux::unary_function_terminal< FunT > > > :
Chris@16:     public mpl::false_
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: } // namespace result_of
Chris@16: 
Chris@16: } // namespace phoenix
Chris@16: 
Chris@16: #endif // BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_