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 filter.hpp
9 * \author Andrey Semashev
10 * \date 13.07.2012
11 *
12 * The header contains a filter function object definition.
13 */
14
15#ifndef BOOST_LOG_EXPRESSIONS_FILTER_HPP_INCLUDED_
16#define BOOST_LOG_EXPRESSIONS_FILTER_HPP_INCLUDED_
17
18#include <boost/move/core.hpp>
19#include <boost/move/utility_core.hpp>
20#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
21#include <boost/type_traits/is_same.hpp>
22#include <boost/type_traits/remove_cv.hpp>
23#include <boost/log/detail/sfinae_tools.hpp>
24#endif
25#include <boost/log/detail/config.hpp>
26#include <boost/log/attributes/attribute_value_set.hpp>
27#include <boost/log/detail/light_function.hpp>
28#include <boost/log/detail/header.hpp>
29
30#ifdef BOOST_HAS_PRAGMA_ONCE
31#pragma once
32#endif
33
34namespace boost {
35
36BOOST_LOG_OPEN_NAMESPACE
37
38/*!
39 * Log record filter function wrapper.
40 */
41class filter
42{
43 BOOST_COPYABLE_AND_MOVABLE(filter)
44
45public:
46 //! Result type
47 typedef bool result_type;
48
49private:
50 //! Filter function type
51 typedef boost::log::aux::light_function< bool (attribute_value_set const&) > filter_type;
52
53 //! Default filter, always returns \c true
54 struct default_filter
55 {
56 typedef bool result_type;
57 result_type operator() (attribute_value_set const&) const { return true; }
58 };
59
60private:
61 //! Filter function
62 filter_type m_Filter;
63
64public:
65 /*!
66 * Default constructor. Creates a filter that always returns \c true.
67 */
68 filter() : m_Filter(default_filter())
69 {
70 }
71 /*!
72 * Copy constructor
73 */
74 filter(filter const& that) : m_Filter(that.m_Filter)
75 {
76 }
77 /*!
78 * Move constructor. The moved-from filter is left in an unspecified state.
79 */
80 filter(BOOST_RV_REF(filter) that) BOOST_NOEXCEPT : m_Filter(boost::move(t&: that.m_Filter))
81 {
82 }
83
84 /*!
85 * Initializing constructor. Creates a filter which will invoke the specified function object.
86 */
87#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
88 template< typename FunT >
89 filter(FunT&& fun) : m_Filter(boost::forward< FunT >(fun))
90 {
91 }
92#elif !defined(BOOST_MSVC) || BOOST_MSVC >= 1600
93 template< typename FunT >
94 filter(FunT const& fun, typename boost::disable_if_c< move_detail::is_rv< FunT >::value, boost::log::aux::sfinae_dummy >::type = boost::log::aux::sfinae_dummy()) : m_Filter(fun)
95 {
96 }
97#else
98 // MSVC 9 and older blows up in unexpected ways if we use SFINAE to disable constructor instantiation
99 template< typename FunT >
100 filter(FunT const& fun) : m_Filter(fun)
101 {
102 }
103 template< typename FunT >
104 filter(rv< FunT >& fun) : m_Filter(fun)
105 {
106 }
107 template< typename FunT >
108 filter(rv< FunT > const& fun) : m_Filter(static_cast< FunT const& >(fun))
109 {
110 }
111 filter(rv< filter > const& that) : m_Filter(that.m_Filter)
112 {
113 }
114#endif
115
116 /*!
117 * Move assignment. The moved-from filter is left in an unspecified state.
118 */
119 filter& operator= (BOOST_RV_REF(filter) that) BOOST_NOEXCEPT
120 {
121 m_Filter.swap(that&: that.m_Filter);
122 return *this;
123 }
124 /*!
125 * Copy assignment.
126 */
127 filter& operator= (BOOST_COPY_ASSIGN_REF(filter) that)
128 {
129 m_Filter = that.m_Filter;
130 return *this;
131 }
132 /*!
133 * Initializing assignment. Sets the specified function object to the filter.
134 */
135#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
136 template< typename FunT >
137 filter& operator= (FunT const& fun)
138#else
139 template< typename FunT >
140 typename boost::disable_if_c< is_same< typename remove_cv< FunT >::type, filter >::value, filter& >::type
141 operator= (FunT const& fun)
142#endif
143 {
144 filter(fun).swap(that&: *this);
145 return *this;
146 }
147
148 /*!
149 * Filtering operator.
150 *
151 * \param values Attribute values of the log record.
152 * \return \c true if the log record passes the filter, \c false otherwise.
153 */
154 result_type operator() (attribute_value_set const& values) const
155 {
156 return m_Filter(values);
157 }
158
159 /*!
160 * Resets the filter to the default. The default filter always returns \c true.
161 */
162 void reset()
163 {
164 m_Filter = default_filter();
165 }
166
167 /*!
168 * Swaps two filters
169 */
170 void swap(filter& that) BOOST_NOEXCEPT
171 {
172 m_Filter.swap(that&: that.m_Filter);
173 }
174};
175
176inline void swap(filter& left, filter& right) BOOST_NOEXCEPT
177{
178 left.swap(that&: right);
179}
180
181BOOST_LOG_CLOSE_NAMESPACE // namespace log
182
183} // namespace boost
184
185#include <boost/log/detail/footer.hpp>
186
187#endif // BOOST_LOG_EXPRESSIONS_FILTER_HPP_INCLUDED_
188

source code of boost/libs/log/include/boost/log/expressions/filter.hpp