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1 | /* | |
2 | * Copyright Andrey Semashev 2007 - 2015. | |
3 | * Distributed under the Boost Software License, Version 1.0. | |
4 | * (See accompanying file LICENSE_1_0.txt or copy at | |
5 | * http://www.boost.org/LICENSE_1_0.txt) | |
6 | */ | |
7 | /*! | |
8 | * \file unary_function_terminal.hpp | |
9 | * \author Andrey Semashev | |
10 | * \date 21.07.2012 | |
11 | * | |
12 | * The header contains attribute value extractor adapter for constructing expression template terminals. | |
13 | */ | |
14 | ||
15 | #ifndef BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_ | |
16 | #define BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_ | |
17 | ||
18 | #include <boost/mpl/bool.hpp> | |
19 | #include <boost/utility/result_of.hpp> | |
20 | #include <boost/fusion/sequence/intrinsic/at_c.hpp> | |
21 | #include <boost/phoenix/core/is_nullary.hpp> | |
22 | #include <boost/phoenix/core/environment.hpp> | |
23 | #include <boost/type_traits/remove_cv.hpp> | |
24 | #include <boost/type_traits/remove_reference.hpp> | |
25 | #include <boost/log/detail/config.hpp> | |
26 | #include <boost/log/detail/copy_cv.hpp> | |
27 | #include <boost/log/detail/custom_terminal_spec.hpp> | |
28 | #include <boost/log/detail/header.hpp> | |
29 | ||
30 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
31 | #pragma once | |
32 | #endif | |
33 | ||
34 | namespace boost { | |
35 | ||
36 | BOOST_LOG_OPEN_NAMESPACE | |
37 | ||
38 | namespace expressions { | |
39 | ||
40 | namespace aux { | |
41 | ||
42 | /*! | |
43 | * \brief An adapter for a unary function to be used as a terminal in a Boost.Phoenix expression | |
44 | * | |
45 | * This class is an adapter between Boost.Phoenix expression invocation protocol and | |
46 | * a unary function. It forwards the call to the base function, passing only the first argument | |
47 | * from the original call. This allows to embed value extractors in template expressions. | |
48 | */ | |
49 | template< typename FunT > | |
50 | class unary_function_terminal | |
51 | { | |
52 | private: | |
53 | //! Adopted function type | |
54 | typedef FunT function_type; | |
55 | //! Self type | |
56 | typedef unary_function_terminal< function_type > this_type; | |
57 | ||
58 | public: | |
59 | //! Internal typedef for type categorization | |
60 | typedef void _is_boost_log_terminal; | |
61 | ||
62 | //! Function result type | |
63 | template< typename > | |
64 | struct result; | |
65 | ||
66 | template< typename ThisT, typename ContextT > | |
67 | struct result< ThisT(ContextT) > | |
68 | { | |
69 | typedef typename remove_cv< | |
70 | typename remove_reference< typename phoenix::result_of::env< ContextT >::type >::type | |
71 | >::type env_type; | |
72 | typedef typename env_type::args_type args_type; | |
73 | typedef typename boost::log::aux::copy_cv< ThisT, function_type >::type cv_function_type; | |
74 | ||
75 | typedef typename boost::result_of< cv_function_type(typename fusion::result_of::at_c< args_type, 0 >::type) >::type type; | |
76 | }; | |
77 | ||
78 | private: | |
79 | //! Adopted function | |
80 | function_type m_fun; | |
81 | ||
82 | public: | |
83 | //! Default constructor | |
84 | BOOST_DEFAULTED_FUNCTION(unary_function_terminal(), {}) | |
85 | //! Copy constructor | |
86 | unary_function_terminal(unary_function_terminal const& that) : m_fun(that.m_fun) {} | |
87 | //! Initializing constructor | |
88 | template< typename ArgT1 > | |
89 | explicit unary_function_terminal(ArgT1 const& arg1) : m_fun(arg1) {} | |
90 | //! Initializing constructor | |
91 | template< typename ArgT1, typename ArgT2 > | |
92 | unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2) : m_fun(arg1, arg2) {} | |
93 | //! Initializing constructor | |
94 | template< typename ArgT1, typename ArgT2, typename ArgT3 > | |
95 | unary_function_terminal(ArgT1 const& arg1, ArgT2 const& arg2, ArgT3 const& arg3) : m_fun(arg1, arg2, arg3) {} | |
96 | ||
97 | //! The operator forwards the call to the base function | |
98 | template< typename ContextT > | |
99 | typename result< this_type(ContextT const&) >::type | |
100 | operator() (ContextT const& ctx) | |
101 | { | |
102 | return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args())); | |
103 | } | |
104 | ||
105 | //! The operator forwards the call to the base function | |
106 | template< typename ContextT > | |
107 | typename result< const this_type(ContextT const&) >::type | |
108 | operator() (ContextT const& ctx) const | |
109 | { | |
110 | return m_fun(fusion::at_c< 0 >(phoenix::env(ctx).args())); | |
111 | } | |
112 | }; | |
113 | ||
114 | } // namespace aux | |
115 | ||
116 | } // namespace expressions | |
117 | ||
118 | BOOST_LOG_CLOSE_NAMESPACE // namespace log | |
119 | ||
120 | #ifndef BOOST_LOG_DOXYGEN_PASS | |
121 | ||
122 | namespace phoenix { | |
123 | ||
124 | namespace result_of { | |
125 | ||
126 | template< typename FunT > | |
127 | struct is_nullary< custom_terminal< boost::log::expressions::aux::unary_function_terminal< FunT > > > : | |
128 | public mpl::false_ | |
129 | { | |
130 | }; | |
131 | ||
132 | } // namespace result_of | |
133 | ||
134 | } // namespace phoenix | |
135 | ||
136 | #endif // BOOST_LOG_DOXYGEN_PASS | |
137 | ||
138 | } // namespace boost | |
139 | ||
140 | #include <boost/log/detail/footer.hpp> | |
141 | ||
142 | #endif // BOOST_LOG_DETAIL_UNARY_FUNCTION_TERMINAL_HPP_INCLUDED_ |