152 lines
4.5 KiB
C++
152 lines
4.5 KiB
C++
/*
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* Copyright Andrey Semashev 2007 - 2013.
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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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/*!
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* \file unary_function_terminal.hpp
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* \author Andrey Semashev
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* \date 21.07.2012
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*
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* The header contains attribute value extractor adapter for constructing expression template terminals.
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*/
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#ifndef BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_
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#define BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_
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#include <boost/mpl/bool.hpp>
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#include <boost/utility/result_of.hpp>
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#include <boost/fusion/sequence/intrinsic/at_c.hpp>
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#include <boost/phoenix/core/is_nullary.hpp>
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#include <boost/phoenix/core/environment.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/log/detail/config.hpp>
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#include <boost/log/detail/custom_terminal_spec.hpp>
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#include <boost/log/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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BOOST_LOG_OPEN_NAMESPACE
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namespace expressions {
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namespace aux {
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/*!
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* \brief An adapter for a unary function to be used as a terminal in a Boost.Phoenix expression
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*
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* This class is an adapter between Boost.Phoenix expression invocation protocol and
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* a unary function. It forwards the call to the base function, passing only the first argument
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* from the original call. This allows to embed value extractors in template expressions.
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*/
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template< typename FunT >
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class unary_function_terminal
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{
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private:
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//! Adopted function type
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typedef FunT function_type;
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//! Self type
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typedef unary_function_terminal< function_type > this_type;
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public:
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//! Internal typedef for type categorization
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typedef void _is_boost_log_terminal;
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//! Function result type
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template< typename >
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struct result;
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template< typename ContextT >
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struct result< this_type(ContextT) >
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{
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typedef typename remove_cv<
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typename remove_reference< typename phoenix::result_of::env< ContextT >::type >::type
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>::type env_type;
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typedef typename env_type::args_type args_type;
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typedef typename boost::result_of< function_type(typename fusion::result_of::at_c< args_type, 0 >::type) >::type type;
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};
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template< typename ContextT >
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struct result< const this_type(ContextT) >
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{
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typedef typename remove_cv<
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typename remove_reference< typename phoenix::result_of::env< ContextT >::type >::type
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>::type env_type;
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typedef typename env_type::args_type args_type;
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typedef typename boost::result_of< const function_type(typename fusion::result_of::at_c< args_type, 0 >::type) >::type type;
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};
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private:
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//! Adopted function
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function_type m_fun;
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public:
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//! Default constructor
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BOOST_DEFAULTED_FUNCTION(unary_function_terminal(), {})
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//! Copy constructor
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unary_function_terminal(unary_function_terminal const& that) : m_fun(that.m_fun) {}
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//! Initializing constructor
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template< typename ArgT1 >
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explicit unary_function_terminal(ArgT1 const& arg1) : m_fun(arg1) {}
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//! Initializing constructor
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template< typename ArgT1, typename ArgT2 >
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unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2) : m_fun(arg1, arg2) {}
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//! Initializing constructor
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template< typename ArgT1, typename ArgT2, typename ArgT3 >
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unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2, ArgT3 const& arg3) : m_fun(arg1, arg2, arg3) {}
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//! The operator forwards the call to the base function
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template< typename ContextT >
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typename result< this_type(ContextT const&) >::type
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operator() (ContextT const& ctx)
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{
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return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args()));
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}
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//! The operator forwards the call to the base function
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template< typename ContextT >
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typename result< const this_type(ContextT const&) >::type
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operator() (ContextT const& ctx) const
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{
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return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args()));
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}
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};
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} // namespace aux
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} // namespace expressions
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BOOST_LOG_CLOSE_NAMESPACE // namespace log
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#ifndef BOOST_LOG_DOXYGEN_PASS
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namespace phoenix {
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namespace result_of {
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template< typename FunT >
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struct is_nullary< custom_terminal< boost::log::expressions::aux::unary_function_terminal< FunT > > > :
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public mpl::false_
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{
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};
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} // namespace result_of
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} // namespace phoenix
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#endif // BOOST_LOG_DOXYGEN_PASS
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} // namespace boost
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#include <boost/log/detail/footer.hpp>
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#endif // BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_
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