Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   has_attr.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   23.07.2012
Chris@16:  *
Chris@16:  * The header contains implementation of a generic attribute presence checker in template expressions.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_EXPRESSIONS_PREDICATES_HAS_ATTR_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_EXPRESSIONS_PREDICATES_HAS_ATTR_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/phoenix/core/actor.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/core/record_view.hpp>
Chris@16: #include <boost/log/attributes/attribute_name.hpp>
Chris@16: #include <boost/log/attributes/attribute_value_set.hpp>
Chris@16: #include <boost/log/attributes/value_visitation.hpp>
Chris@16: #include <boost/log/expressions/keyword_fwd.hpp>
Chris@16: #include <boost/log/detail/unary_function_terminal.hpp>
Chris@16: #include <boost/log/utility/functional/nop.hpp>
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace expressions {
Chris@16: 
Chris@16: /*!
Chris@16:  * An attribute value presence checker.
Chris@16:  */
Chris@16: template< typename T >
Chris@16: class has_attribute
Chris@16: {
Chris@16: public:
Chris@16:     //! Function result_type
Chris@16:     typedef bool result_type;
Chris@16:     //! Expected attribute value type
Chris@16:     typedef T value_type;
Chris@16: 
Chris@16: private:
Chris@16:     //! Attribute value name
Chris@16:     const attribute_name m_name;
Chris@16:     //! Visitor invoker
Chris@16:     value_visitor_invoker< value_type > m_visitor_invoker;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor
Chris@16:      *
Chris@16:      * \param name Attribute name
Chris@16:      */
Chris@16:     explicit has_attribute(attribute_name const& name) : m_name(name)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     /*!
Chris@16:      * Checking operator
Chris@16:      *
Chris@16:      * \param arg A set of attribute values or a log record
Chris@16:      * \return \c true if the log record contains the sought attribute value, \c false otherwise
Chris@16:      */
Chris@16:     template< typename ArgT >
Chris@16:     result_type operator() (ArgT const& arg) const
Chris@16:     {
Chris@16:         return m_visitor_invoker(m_name, arg, nop()).code() == visitation_result::ok;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16:  * An attribute value presence checker. This specialization does not check the type of the attribute value.
Chris@16:  */
Chris@16: template< >
Chris@16: class has_attribute< void >
Chris@16: {
Chris@16: public:
Chris@16:     //! Function result_type
Chris@16:     typedef bool result_type;
Chris@16:     //! Expected attribute value type
Chris@16:     typedef void value_type;
Chris@16: 
Chris@16: private:
Chris@16:     //! Attribute name
Chris@16:     const attribute_name m_name;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor
Chris@16:      *
Chris@16:      * \param name Attribute name
Chris@16:      */
Chris@16:     explicit has_attribute(attribute_name const& name) : m_name(name)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     /*!
Chris@16:      * Checking operator
Chris@16:      *
Chris@16:      * \param attrs A set of attribute values
Chris@16:      * \return \c true if the log record contains the sought attribute value, \c false otherwise
Chris@16:      */
Chris@16:     result_type operator() (attribute_value_set const& attrs) const
Chris@16:     {
Chris@16:         return attrs.find(m_name) != attrs.end();
Chris@16:     }
Chris@16: 
Chris@16:     /*!
Chris@16:      * Checking operator
Chris@16:      *
Chris@16:      * \param rec A log record
Chris@16:      * \return \c true if the log record contains the sought attribute value, \c false otherwise
Chris@16:      */
Chris@16:     result_type operator() (boost::log::record_view const& rec) const
Chris@16:     {
Chris@16:         return operator()(rec.attribute_values());
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16:  * The function generates a terminal node in a template expression. The node will check for the attribute value
Chris@16:  * presence in a log record. The node will also check that the attribute value has the specified type, if present.
Chris@16:  */
Chris@16: template< typename AttributeValueT >
Chris@16: BOOST_FORCEINLINE phoenix::actor< aux::unary_function_terminal< has_attribute< AttributeValueT > > > has_attr(attribute_name const& name)
Chris@16: {
Chris@16:     typedef aux::unary_function_terminal< has_attribute< AttributeValueT > > terminal_type;
Chris@16:     phoenix::actor< terminal_type > act = {{ terminal_type(name) }};
Chris@16:     return act;
Chris@16: }
Chris@16: 
Chris@16: /*!
Chris@16:  * The function generates a terminal node in a template expression. The node will check for the attribute value
Chris@16:  * presence in a log record.
Chris@16:  */
Chris@16: BOOST_FORCEINLINE phoenix::actor< aux::unary_function_terminal< has_attribute< void > > > has_attr(attribute_name const& name)
Chris@16: {
Chris@16:     typedef aux::unary_function_terminal< has_attribute< void > > terminal_type;
Chris@16:     phoenix::actor< terminal_type > act = {{ terminal_type(name) }};
Chris@16:     return act;
Chris@16: }
Chris@16: 
Chris@16: /*!
Chris@16:  * The function generates a terminal node in a template expression. The node will check for the attribute value
Chris@16:  * presence in a log record. The node will also check that the attribute value has the specified type, if present.
Chris@16:  */
Chris@16: template< typename DescriptorT, template< typename > class ActorT >
Chris@16: BOOST_FORCEINLINE ActorT< aux::unary_function_terminal< has_attribute< typename DescriptorT::value_type > > > has_attr(attribute_keyword< DescriptorT, ActorT > const&)
Chris@16: {
Chris@16:     typedef aux::unary_function_terminal< has_attribute< typename DescriptorT::value_type > > terminal_type;
Chris@16:     ActorT< terminal_type > act = {{ terminal_type(DescriptorT::get_name()) }};
Chris@16:     return act;
Chris@16: }
Chris@16: 
Chris@16: } // namespace expressions
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_EXPRESSIONS_PREDICATES_HAS_ATTR_HPP_INCLUDED_