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   attribute_mapping.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   07.11.2008
Chris@16:  *
Chris@16:  * The header contains facilities that are used in different sinks to map attribute values
Chris@16:  * used throughout the application to values used with the specific native logging API.
Chris@16:  * These tools are mostly needed to map application severity levels on native levels,
Chris@16:  * required by OS-specific sink backends.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_SINKS_ATTRIBUTE_MAPPING_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_SINKS_ATTRIBUTE_MAPPING_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <map>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/detail/tagged_integer.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/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 sinks {
Chris@16: 
Chris@16: //! Base class for attribute mapping function objects
Chris@16: template< typename MappedT >
Chris@16: struct basic_mapping
Chris@16: {
Chris@16:     //! Mapped value type
Chris@16:     typedef MappedT mapped_type;
Chris@16:     //! Result type
Chris@16:     typedef mapped_type result_type;
Chris@16: };
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16:     //! Attribute value visitor
Chris@16:     template< typename MappedT >
Chris@16:     struct direct_mapping_visitor
Chris@16:     {
Chris@16:         typedef void result_type;
Chris@16:         typedef MappedT mapped_type;
Chris@16: 
Chris@16:         explicit direct_mapping_visitor(mapped_type& extracted) :
Chris@16:             m_Extracted(extracted)
Chris@16:         {
Chris@16:         }
Chris@16:         template< typename T >
Chris@16:         void operator() (T const& val) const
Chris@16:         {
Chris@16:             m_Extracted = mapped_type(val);
Chris@16:         }
Chris@16: 
Chris@16:     private:
Chris@16:         mapped_type& m_Extracted;
Chris@16:     };
Chris@16:     //  Specialization for the tagged integer
Chris@16:     template< typename IntT, typename TagT >
Chris@16:     struct direct_mapping_visitor< boost::log::aux::tagged_integer< IntT, TagT > >
Chris@16:     {
Chris@16:         typedef void result_type;
Chris@16:         typedef boost::log::aux::tagged_integer< IntT, TagT > mapped_type;
Chris@16: 
Chris@16:         explicit direct_mapping_visitor(mapped_type& extracted) :
Chris@16:             m_Extracted(extracted)
Chris@16:         {
Chris@16:         }
Chris@16:         template< typename T >
Chris@16:         void operator() (T const& val) const
Chris@16:         {
Chris@16:             mapped_type v = { val };
Chris@16:             m_Extracted = v;
Chris@16:         }
Chris@16: 
Chris@16:     private:
Chris@16:         mapped_type& m_Extracted;
Chris@16:     };
Chris@16: 
Chris@16: } // namespace aux
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief Straightforward mapping
Chris@16:  *
Chris@16:  * This type of mapping assumes that attribute with a particular name always
Chris@16:  * provides values that map directly onto the native values. The mapping
Chris@16:  * simply returns the extracted attribute value converted to the native value.
Chris@16:  */
Chris@16: template< typename MappedT, typename AttributeValueT = int >
Chris@16: class basic_direct_mapping :
Chris@16:     public basic_mapping< MappedT >
Chris@16: {
Chris@16:     //! Base type
Chris@16:     typedef basic_direct_mapping< MappedT > base_type;
Chris@16: 
Chris@16: public:
Chris@16:     //! Attribute contained value type
Chris@16:     typedef AttributeValueT attribute_value_type;
Chris@16:     //! Mapped value type
Chris@16:     typedef typename base_type::mapped_type mapped_type;
Chris@16: 
Chris@16: private:
Chris@16:     //! Attribute name
Chris@16:     const attribute_name m_Name;
Chris@16:     //! Visitor invoker for the attribute value
Chris@16:     value_visitor_invoker< attribute_value_type > m_Invoker;
Chris@16:     //! Default native value
Chris@16:     mapped_type m_DefaultValue;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Constructor
Chris@16:      *
Chris@16:      * \param name Attribute name
Chris@16:      * \param default_value The default native value that is returned if the attribute value is not found
Chris@16:      */
Chris@16:     explicit basic_direct_mapping(attribute_name const& name, mapped_type const& default_value) :
Chris@16:         m_Name(name),
Chris@16:         m_DefaultValue(default_value)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     /*!
Chris@16:      * Extraction operator
Chris@16:      *
Chris@16:      * \param rec A log record to extract value from
Chris@16:      * \return An extracted attribute value
Chris@16:      */
Chris@16:     mapped_type operator() (record_view const& rec) const
Chris@16:     {
Chris@16:         mapped_type res = m_DefaultValue;
Chris@16:         aux::direct_mapping_visitor< mapped_type > vis(res);
Chris@16:         m_Invoker(m_Name, rec.attribute_values(), vis);
Chris@16:         return res;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief Customizable mapping
Chris@16:  *
Chris@16:  * The class allows to setup a custom mapping between an attribute and native values.
Chris@16:  * The mapping should be initialized similarly to the standard \c map container, by using
Chris@16:  * indexing operator and assignment.
Chris@16:  *
Chris@16:  * \note Unlike many other components of the library, exact type of the attribute value
Chris@16:  *       must be specified in the template parameter \c AttributeValueT. Type sequences
Chris@16:  *       are not supported.
Chris@16:  */
Chris@16: template< typename MappedT, typename AttributeValueT = int >
Chris@16: class basic_custom_mapping :
Chris@16:     public basic_mapping< MappedT >
Chris@16: {
Chris@16:     //! Base type
Chris@16:     typedef basic_mapping< MappedT > base_type;
Chris@16: 
Chris@16: public:
Chris@16:     //! Attribute contained value type
Chris@16:     typedef AttributeValueT attribute_value_type;
Chris@16:     //! Mapped value type
Chris@16:     typedef typename base_type::mapped_type mapped_type;
Chris@16: 
Chris@16: private:
Chris@16:     //! \cond
Chris@16: 
Chris@16:     //! Mapping type
Chris@16:     typedef std::map< attribute_value_type, mapped_type > mapping_type;
Chris@16:     //! Smart reference class for implementing insertion into the map
Chris@16:     class reference_proxy;
Chris@16:     friend class reference_proxy;
Chris@16:     class reference_proxy
Chris@16:     {
Chris@16:         mapping_type& m_Mapping;
Chris@16:         attribute_value_type m_Key;
Chris@16: 
Chris@16:     public:
Chris@16:         //! Constructor
Chris@16:         reference_proxy(mapping_type& mapping, attribute_value_type const& key) : m_Mapping(mapping), m_Key(key) {}
Chris@16:         //! Insertion
Chris@16:         reference_proxy const& operator= (mapped_type const& val) const
Chris@16:         {
Chris@16:             m_Mapping[m_Key] = val;
Chris@16:             return *this;
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     //! Attribute value visitor
Chris@16:     struct visitor;
Chris@16:     friend struct visitor;
Chris@16:     struct visitor
Chris@16:     {
Chris@16:         typedef void result_type;
Chris@16: 
Chris@16:         visitor(mapping_type const& mapping, mapped_type& extracted) :
Chris@16:             m_Mapping(mapping),
Chris@16:             m_Extracted(extracted)
Chris@16:         {
Chris@16:         }
Chris@16:         template< typename T >
Chris@16:         void operator() (T const& val) const
Chris@16:         {
Chris@16:             typename mapping_type::const_iterator it = m_Mapping.find(val);
Chris@16:             if (it != m_Mapping.end())
Chris@16:                 m_Extracted = it->second;
Chris@16:         }
Chris@16: 
Chris@16:     private:
Chris@16:         mapping_type const& m_Mapping;
Chris@16:         mapped_type& m_Extracted;
Chris@16:     };
Chris@16: 
Chris@16:     //! \endcond
Chris@16: 
Chris@16: private:
Chris@16:     //! Attribute name
Chris@16:     const attribute_name m_Name;
Chris@16:     //! Visitor invoker for the attribute value
Chris@16:     value_visitor_invoker< attribute_value_type > m_Invoker;
Chris@16:     //! Default native value
Chris@16:     mapped_type m_DefaultValue;
Chris@16:     //! Conversion mapping
Chris@16:     mapping_type m_Mapping;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Constructor
Chris@16:      *
Chris@16:      * \param name Attribute name
Chris@16:      * \param default_value The default native value that is returned if the conversion cannot be performed
Chris@16:      */
Chris@16:     explicit basic_custom_mapping(attribute_name const& name, mapped_type const& default_value) :
Chris@16:         m_Name(name),
Chris@16:         m_DefaultValue(default_value)
Chris@16:     {
Chris@16:     }
Chris@16:     /*!
Chris@16:      * Extraction operator. Extracts the attribute value and attempts to map it onto
Chris@16:      * the native value.
Chris@16:      *
Chris@16:      * \param rec A log record to extract value from
Chris@16:      * \return A mapped value, if mapping was successful, or the default value if
Chris@16:      *         mapping did not succeed.
Chris@16:      */
Chris@16:     mapped_type operator() (record_view const& rec) const
Chris@16:     {
Chris@16:         mapped_type res = m_DefaultValue;
Chris@16:         visitor vis(m_Mapping, res);
Chris@16:         m_Invoker(m_Name, rec.attribute_values(), vis);
Chris@16:         return res;
Chris@16:     }
Chris@16:     /*!
Chris@16:      * Insertion operator
Chris@16:      *
Chris@16:      * \param key Attribute value to be mapped
Chris@16:      * \return An object of unspecified type that allows to insert a new mapping through assignment.
Chris@16:      *         The \a key argument becomes the key attribute value, and the assigned value becomes the
Chris@16:      *         mapped native value.
Chris@16:      */
Chris@16: #ifndef BOOST_LOG_DOXYGEN_PASS
Chris@16:     reference_proxy operator[] (attribute_value_type const& key)
Chris@16: #else
Chris@16:     implementation_defined operator[] (attribute_value_type const& key)
Chris@16: #endif
Chris@16:     {
Chris@16:         return reference_proxy(m_Mapping, key);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } // namespace sinks
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_SINKS_ATTRIBUTE_MAPPING_HPP_INCLUDED_