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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 has_attr.hpp | |
9 | * \author Andrey Semashev | |
10 | * \date 23.07.2012 | |
11 | * | |
12 | * The header contains implementation of a generic attribute presence checker in template expressions. | |
13 | */ | |
14 | ||
15 | #ifndef BOOST_LOG_EXPRESSIONS_PREDICATES_HAS_ATTR_HPP_INCLUDED_ | |
16 | #define BOOST_LOG_EXPRESSIONS_PREDICATES_HAS_ATTR_HPP_INCLUDED_ | |
17 | ||
18 | #include <boost/phoenix/core/actor.hpp> | |
19 | #include <boost/log/detail/config.hpp> | |
20 | #include <boost/log/core/record_view.hpp> | |
21 | #include <boost/log/attributes/attribute_name.hpp> | |
22 | #include <boost/log/attributes/attribute_value_set.hpp> | |
23 | #include <boost/log/attributes/value_visitation.hpp> | |
24 | #include <boost/log/expressions/keyword_fwd.hpp> | |
25 | #include <boost/log/detail/unary_function_terminal.hpp> | |
26 | #include <boost/log/utility/functional/nop.hpp> | |
27 | #include <boost/log/detail/header.hpp> | |
28 | ||
29 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
30 | #pragma once | |
31 | #endif | |
32 | ||
33 | namespace boost { | |
34 | ||
35 | BOOST_LOG_OPEN_NAMESPACE | |
36 | ||
37 | namespace expressions { | |
38 | ||
39 | /*! | |
40 | * An attribute value presence checker. | |
41 | */ | |
42 | template< typename T > | |
43 | class has_attribute | |
44 | { | |
45 | public: | |
46 | //! Function result_type | |
47 | typedef bool result_type; | |
48 | //! Expected attribute value type | |
49 | typedef T value_type; | |
50 | ||
51 | private: | |
52 | //! Attribute value name | |
53 | const attribute_name m_name; | |
54 | //! Visitor invoker | |
55 | value_visitor_invoker< value_type > m_visitor_invoker; | |
56 | ||
57 | public: | |
58 | /*! | |
59 | * Initializing constructor | |
60 | * | |
61 | * \param name Attribute name | |
62 | */ | |
63 | explicit has_attribute(attribute_name const& name) : m_name(name) | |
64 | { | |
65 | } | |
66 | ||
67 | /*! | |
68 | * Checking operator | |
69 | * | |
70 | * \param arg A set of attribute values or a log record | |
71 | * \return \c true if the log record contains the sought attribute value, \c false otherwise | |
72 | */ | |
73 | template< typename ArgT > | |
74 | result_type operator() (ArgT const& arg) const | |
75 | { | |
76 | return m_visitor_invoker(m_name, arg, nop()).code() == visitation_result::ok; | |
77 | } | |
78 | }; | |
79 | ||
80 | /*! | |
81 | * An attribute value presence checker. This specialization does not check the type of the attribute value. | |
82 | */ | |
83 | template< > | |
84 | class has_attribute< void > | |
85 | { | |
86 | public: | |
87 | //! Function result_type | |
88 | typedef bool result_type; | |
89 | //! Expected attribute value type | |
90 | typedef void value_type; | |
91 | ||
92 | private: | |
93 | //! Attribute name | |
94 | const attribute_name m_name; | |
95 | ||
96 | public: | |
97 | /*! | |
98 | * Initializing constructor | |
99 | * | |
100 | * \param name Attribute name | |
101 | */ | |
102 | explicit has_attribute(attribute_name const& name) : m_name(name) | |
103 | { | |
104 | } | |
105 | ||
106 | /*! | |
107 | * Checking operator | |
108 | * | |
109 | * \param attrs A set of attribute values | |
110 | * \return \c true if the log record contains the sought attribute value, \c false otherwise | |
111 | */ | |
112 | result_type operator() (attribute_value_set const& attrs) const | |
113 | { | |
114 | return attrs.find(m_name) != attrs.end(); | |
115 | } | |
116 | ||
117 | /*! | |
118 | * Checking operator | |
119 | * | |
120 | * \param rec A log record | |
121 | * \return \c true if the log record contains the sought attribute value, \c false otherwise | |
122 | */ | |
123 | result_type operator() (boost::log::record_view const& rec) const | |
124 | { | |
125 | return operator()(rec.attribute_values()); | |
126 | } | |
127 | }; | |
128 | ||
129 | /*! | |
130 | * The function generates a terminal node in a template expression. The node will check for the attribute value | |
131 | * presence in a log record. The node will also check that the attribute value has the specified type, if present. | |
132 | */ | |
133 | template< typename AttributeValueT > | |
134 | BOOST_FORCEINLINE phoenix::actor< aux::unary_function_terminal< has_attribute< AttributeValueT > > > has_attr(attribute_name const& name) | |
135 | { | |
136 | typedef aux::unary_function_terminal< has_attribute< AttributeValueT > > terminal_type; | |
137 | phoenix::actor< terminal_type > act = {{ terminal_type(name) }}; | |
138 | return act; | |
139 | } | |
140 | ||
141 | /*! | |
142 | * The function generates a terminal node in a template expression. The node will check for the attribute value | |
143 | * presence in a log record. | |
144 | */ | |
145 | BOOST_FORCEINLINE phoenix::actor< aux::unary_function_terminal< has_attribute< void > > > has_attr(attribute_name const& name) | |
146 | { | |
147 | typedef aux::unary_function_terminal< has_attribute< void > > terminal_type; | |
148 | phoenix::actor< terminal_type > act = {{ terminal_type(name) }}; | |
149 | return act; | |
150 | } | |
151 | ||
152 | /*! | |
153 | * The function generates a terminal node in a template expression. The node will check for the attribute value | |
154 | * presence in a log record. The node will also check that the attribute value has the specified type, if present. | |
155 | */ | |
156 | template< typename DescriptorT, template< typename > class ActorT > | |
157 | BOOST_FORCEINLINE ActorT< aux::unary_function_terminal< has_attribute< typename DescriptorT::value_type > > > has_attr(attribute_keyword< DescriptorT, ActorT > const&) | |
158 | { | |
159 | typedef aux::unary_function_terminal< has_attribute< typename DescriptorT::value_type > > terminal_type; | |
160 | ActorT< terminal_type > act = {{ terminal_type(DescriptorT::get_name()) }}; | |
161 | return act; | |
162 | } | |
163 | ||
164 | } // namespace expressions | |
165 | ||
166 | BOOST_LOG_CLOSE_NAMESPACE // namespace log | |
167 | ||
168 | } // namespace boost | |
169 | ||
170 | #include <boost/log/detail/footer.hpp> | |
171 | ||
172 | #endif // BOOST_LOG_EXPRESSIONS_PREDICATES_HAS_ATTR_HPP_INCLUDED_ |