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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 keyword.hpp | |
9 | * \author Andrey Semashev | |
10 | * \date 29.01.2012 | |
11 | * | |
12 | * The header contains attribute keyword declaration. | |
13 | */ | |
14 | ||
15 | #ifndef BOOST_LOG_EXPRESSIONS_KEYWORD_HPP_INCLUDED_ | |
16 | #define BOOST_LOG_EXPRESSIONS_KEYWORD_HPP_INCLUDED_ | |
17 | ||
18 | #include <boost/ref.hpp> | |
19 | #include <boost/proto/extends.hpp> | |
20 | #include <boost/proto/make_expr.hpp> | |
21 | #include <boost/phoenix/core/actor.hpp> | |
22 | #include <boost/phoenix/core/domain.hpp> | |
23 | #include <boost/phoenix/core/environment.hpp> | |
24 | #include <boost/fusion/sequence/intrinsic/at.hpp> | |
25 | #include <boost/preprocessor/cat.hpp> | |
26 | #include <boost/log/detail/config.hpp> | |
27 | #include <boost/log/detail/custom_terminal_spec.hpp> | |
28 | #include <boost/log/expressions/keyword_fwd.hpp> | |
29 | #include <boost/log/expressions/is_keyword_descriptor.hpp> | |
30 | #include <boost/log/expressions/attr.hpp> | |
31 | #include <boost/log/attributes/attribute_name.hpp> | |
32 | #include <boost/log/attributes/value_extraction.hpp> | |
33 | #include <boost/log/attributes/fallback_policy.hpp> | |
34 | #include <boost/log/detail/header.hpp> | |
35 | ||
36 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
37 | #pragma once | |
38 | #endif | |
39 | ||
40 | namespace boost { | |
41 | ||
42 | BOOST_LOG_OPEN_NAMESPACE | |
43 | ||
44 | namespace expressions { | |
45 | ||
46 | /*! | |
47 | * This class implements an expression template keyword. It is used to start template expressions involving attribute values. | |
48 | */ | |
49 | template< typename DescriptorT, template< typename > class ActorT > | |
50 | struct attribute_keyword | |
51 | { | |
52 | //! Self type | |
53 | typedef attribute_keyword this_type; | |
54 | //! Attribute descriptor type | |
55 | typedef DescriptorT descriptor_type; | |
56 | ||
57 | BOOST_PROTO_BASIC_EXTENDS(typename proto::terminal< descriptor_type >::type, this_type, phoenix::phoenix_domain) | |
58 | ||
59 | //! Attribute value type | |
60 | typedef typename descriptor_type::value_type value_type; | |
61 | ||
62 | //! Returns attribute name | |
63 | static attribute_name get_name() { return descriptor_type::get_name(); } | |
64 | ||
65 | //! Expression with cached attribute name | |
66 | typedef attribute_actor< | |
67 | value_type, | |
68 | fallback_to_none, | |
69 | descriptor_type, | |
70 | ActorT | |
71 | > or_none_result_type; | |
72 | ||
73 | //! Generates an expression that extracts the attribute value or a default value | |
74 | static or_none_result_type or_none() | |
75 | { | |
76 | typedef typename or_none_result_type::terminal_type result_terminal; | |
77 | typename or_none_result_type::base_type act = {{ result_terminal(get_name()) }}; | |
78 | return or_none_result_type(act); | |
79 | } | |
80 | ||
81 | //! Expression with cached attribute name | |
82 | typedef attribute_actor< | |
83 | value_type, | |
84 | fallback_to_throw, | |
85 | descriptor_type, | |
86 | ActorT | |
87 | > or_throw_result_type; | |
88 | ||
89 | //! Generates an expression that extracts the attribute value or throws an exception | |
90 | static or_throw_result_type or_throw() | |
91 | { | |
92 | typedef typename or_throw_result_type::terminal_type result_terminal; | |
93 | typename or_throw_result_type::base_type act = {{ result_terminal(get_name()) }}; | |
94 | return or_throw_result_type(act); | |
95 | } | |
96 | ||
97 | //! Generates an expression that extracts the attribute value or a default value | |
98 | template< typename DefaultT > | |
99 | static attribute_actor< | |
100 | value_type, | |
101 | fallback_to_default< DefaultT >, | |
102 | descriptor_type, | |
103 | ActorT | |
104 | > or_default(DefaultT const& def_val) | |
105 | { | |
106 | typedef attribute_actor< | |
107 | value_type, | |
108 | fallback_to_default< DefaultT >, | |
109 | descriptor_type, | |
110 | ActorT | |
111 | > or_default_result_type; | |
112 | typedef typename or_default_result_type::terminal_type result_terminal; | |
113 | typename or_default_result_type::base_type act = {{ result_terminal(get_name(), def_val) }}; | |
114 | return or_default_result_type(act); | |
115 | } | |
116 | }; | |
117 | ||
118 | } // namespace expressions | |
119 | ||
120 | BOOST_LOG_CLOSE_NAMESPACE // namespace log | |
121 | ||
122 | #ifndef BOOST_LOG_DOXYGEN_PASS | |
123 | ||
124 | namespace proto { | |
125 | ||
126 | namespace detail { | |
127 | ||
128 | // This hack is needed in order to cache attribute name into the expression terminal when the template | |
129 | // expression is constructed. The standard way through a custom domain doesn't work because phoenix::actor | |
130 | // is bound to phoenix_domain. | |
131 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
132 | struct protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
133 | { | |
134 | typedef boost::log::expressions::attribute_keyword< DescriptorT, ActorT > keyword_type; | |
135 | typedef typename keyword_type::or_none_result_type result_type; | |
136 | ||
137 | result_type operator() (keyword_type const& keyword) const | |
138 | { | |
139 | return keyword.or_none(); | |
140 | } | |
141 | }; | |
142 | ||
143 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
144 | struct protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >&, DomainT > : | |
145 | public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
146 | { | |
147 | }; | |
148 | ||
149 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
150 | struct protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT > const&, DomainT > : | |
151 | public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
152 | { | |
153 | }; | |
154 | ||
155 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
156 | struct protoify< boost::reference_wrapper< boost::log::expressions::attribute_keyword< DescriptorT, ActorT > >, DomainT > : | |
157 | public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
158 | { | |
159 | }; | |
160 | ||
161 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
162 | struct protoify< boost::reference_wrapper< boost::log::expressions::attribute_keyword< DescriptorT, ActorT > > const, DomainT > : | |
163 | public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
164 | { | |
165 | }; | |
166 | ||
167 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
168 | struct protoify< boost::reference_wrapper< const boost::log::expressions::attribute_keyword< DescriptorT, ActorT > >, DomainT > : | |
169 | public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
170 | { | |
171 | }; | |
172 | ||
173 | template< typename DescriptorT, template< typename > class ActorT, typename DomainT > | |
174 | struct protoify< boost::reference_wrapper< const boost::log::expressions::attribute_keyword< DescriptorT, ActorT > > const, DomainT > : | |
175 | public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT > | |
176 | { | |
177 | }; | |
178 | ||
179 | } // namespace detail | |
180 | ||
181 | } // namespace proto | |
182 | ||
183 | #endif // !defined(BOOST_LOG_DOXYGEN_PASS) | |
184 | ||
185 | } // namespace boost | |
186 | ||
187 | #ifndef BOOST_LOG_DOXYGEN_PASS | |
188 | ||
189 | #define BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE_IMPL(keyword_, name_, value_type_, tag_ns_)\ | |
190 | namespace tag_ns_\ | |
191 | {\ | |
192 | struct keyword_ :\ | |
193 | public ::boost::log::expressions::keyword_descriptor\ | |
194 | {\ | |
195 | typedef value_type_ value_type;\ | |
196 | static ::boost::log::attribute_name get_name() { return ::boost::log::attribute_name(name_); }\ | |
197 | };\ | |
198 | }\ | |
199 | typedef ::boost::log::expressions::attribute_keyword< tag_ns_::keyword_ > BOOST_PP_CAT(keyword_, _type); | |
200 | ||
201 | #define BOOST_LOG_ATTRIBUTE_KEYWORD_IMPL(keyword_, name_, value_type_, tag_ns_)\ | |
202 | BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE_IMPL(keyword_, name_, value_type_, tag_ns_)\ | |
203 | const BOOST_PP_CAT(keyword_, _type) keyword_ = {}; | |
204 | ||
205 | #endif // BOOST_LOG_DOXYGEN_PASS | |
206 | ||
207 | /*! | |
208 | * \brief The macro declares an attribute keyword type | |
209 | * | |
210 | * The macro should be used at a namespace scope. It expands into an attribute keyword type definition, including the | |
211 | * \c tag namespace and the keyword tag type within which has the following layout: | |
212 | * | |
213 | * \code | |
214 | * namespace tag | |
215 | * { | |
216 | * struct keyword_ : | |
217 | * public boost::log::expressions::keyword_descriptor | |
218 | * { | |
219 | * typedef value_type_ value_type; | |
220 | * static boost::log::attribute_name get_name(); | |
221 | * }; | |
222 | * } | |
223 | * | |
224 | * typedef boost::log::expressions::attribute_keyword< tag::keyword_ > keyword_type; | |
225 | * \endcode | |
226 | * | |
227 | * The \c get_name method returns the attribute name. | |
228 | * | |
229 | * \note This macro only defines the type of the keyword. To also define the keyword object, use | |
230 | * the \c BOOST_LOG_ATTRIBUTE_KEYWORD macro instead. | |
231 | * | |
232 | * \param keyword_ Keyword name | |
233 | * \param name_ Attribute name string | |
234 | * \param value_type_ Attribute value type | |
235 | */ | |
236 | #define BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE(keyword_, name_, value_type_)\ | |
237 | BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE_IMPL(keyword_, name_, value_type_, tag) | |
238 | ||
239 | /*! | |
240 | * \brief The macro declares an attribute keyword | |
241 | * | |
242 | * The macro provides definitions similar to \c BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE and additionally | |
243 | * defines the keyword object. | |
244 | * | |
245 | * \param keyword_ Keyword name | |
246 | * \param name_ Attribute name string | |
247 | * \param value_type_ Attribute value type | |
248 | */ | |
249 | #define BOOST_LOG_ATTRIBUTE_KEYWORD(keyword_, name_, value_type_)\ | |
250 | BOOST_LOG_ATTRIBUTE_KEYWORD_IMPL(keyword_, name_, value_type_, tag) | |
251 | ||
252 | #include <boost/log/detail/footer.hpp> | |
253 | ||
254 | #if defined(BOOST_LOG_TRIVIAL_HPP_INCLUDED_) | |
255 | #include <boost/log/detail/trivial_keyword.hpp> | |
256 | #endif | |
257 | ||
258 | #endif // BOOST_LOG_EXPRESSIONS_KEYWORD_HPP_INCLUDED_ |