ceph/src/boost/libs/log/include/boost/log/expressions/predicates/has_attr.hpp

   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_