comparison DEPENDENCIES/generic/include/boost/log/sinks/attribute_mapping.hpp @ 16:2665513ce2d3

Add boost headers

+/*
+ *          Copyright Andrey Semashev 2007 - 2013.
+ * Distributed under the Boost Software License, Version 1.0.
+ *    (See accompanying file LICENSE_1_0.txt or copy at
+ *          http://www.boost.org/LICENSE_1_0.txt)
+ */
+/*!
+ * \file   attribute_mapping.hpp
+ * \author Andrey Semashev
+ * \date   07.11.2008
+ *
+ * The header contains facilities that are used in different sinks to map attribute values
+ * used throughout the application to values used with the specific native logging API.
+ * These tools are mostly needed to map application severity levels on native levels,
+ * required by OS-specific sink backends.
+ */
+
+#ifndef BOOST_LOG_SINKS_ATTRIBUTE_MAPPING_HPP_INCLUDED_
+#define BOOST_LOG_SINKS_ATTRIBUTE_MAPPING_HPP_INCLUDED_
+
+#include <map>
+#include <boost/log/detail/config.hpp>
+#include <boost/log/detail/tagged_integer.hpp>
+#include <boost/log/core/record_view.hpp>
+#include <boost/log/attributes/attribute_name.hpp>
+#include <boost/log/attributes/attribute_value_set.hpp>
+#include <boost/log/attributes/value_visitation.hpp>
+#include <boost/log/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+BOOST_LOG_OPEN_NAMESPACE
+
+namespace sinks {
+
+//! Base class for attribute mapping function objects
+template< typename MappedT >
+struct basic_mapping
+{
+    //! Mapped value type
+    typedef MappedT mapped_type;
+    //! Result type
+    typedef mapped_type result_type;
+};
+
+namespace aux {
+
+    //! Attribute value visitor
+    template< typename MappedT >
+    struct direct_mapping_visitor
+    {
+        typedef void result_type;
+        typedef MappedT mapped_type;
+
+        explicit direct_mapping_visitor(mapped_type& extracted) :
+            m_Extracted(extracted)
+        {
+        }
+        template< typename T >
+        void operator() (T const& val) const
+        {
+            m_Extracted = mapped_type(val);
+        }
+
+    private:
+        mapped_type& m_Extracted;
+    };
+    //  Specialization for the tagged integer
+    template< typename IntT, typename TagT >
+    struct direct_mapping_visitor< boost::log::aux::tagged_integer< IntT, TagT > >
+    {
+        typedef void result_type;
+        typedef boost::log::aux::tagged_integer< IntT, TagT > mapped_type;
+
+        explicit direct_mapping_visitor(mapped_type& extracted) :
+            m_Extracted(extracted)
+        {
+        }
+        template< typename T >
+        void operator() (T const& val) const
+        {
+            mapped_type v = { val };
+            m_Extracted = v;
+        }
+
+    private:
+        mapped_type& m_Extracted;
+    };
+
+} // namespace aux
+
+/*!
+ * \brief Straightforward mapping
+ *
+ * This type of mapping assumes that attribute with a particular name always
+ * provides values that map directly onto the native values. The mapping
+ * simply returns the extracted attribute value converted to the native value.
+ */
+template< typename MappedT, typename AttributeValueT = int >
+class basic_direct_mapping :
+    public basic_mapping< MappedT >
+{
+    //! Base type
+    typedef basic_direct_mapping< MappedT > base_type;
+
+public:
+    //! Attribute contained value type
+    typedef AttributeValueT attribute_value_type;
+    //! Mapped value type
+    typedef typename base_type::mapped_type mapped_type;
+
+private:
+    //! Attribute name
+    const attribute_name m_Name;
+    //! Visitor invoker for the attribute value
+    value_visitor_invoker< attribute_value_type > m_Invoker;
+    //! Default native value
+    mapped_type m_DefaultValue;
+
+public:
+    /*!
+     * Constructor
+     *
+     * \param name Attribute name
+     * \param default_value The default native value that is returned if the attribute value is not found
+     */
+    explicit basic_direct_mapping(attribute_name const& name, mapped_type const& default_value) :
+        m_Name(name),
+        m_DefaultValue(default_value)
+    {
+    }
+
+    /*!
+     * Extraction operator
+     *
+     * \param rec A log record to extract value from
+     * \return An extracted attribute value
+     */
+    mapped_type operator() (record_view const& rec) const
+    {
+        mapped_type res = m_DefaultValue;
+        aux::direct_mapping_visitor< mapped_type > vis(res);
+        m_Invoker(m_Name, rec.attribute_values(), vis);
+        return res;
+    }
+};
+
+/*!
+ * \brief Customizable mapping
+ *
+ * The class allows to setup a custom mapping between an attribute and native values.
+ * The mapping should be initialized similarly to the standard \c map container, by using
+ * indexing operator and assignment.
+ *
+ * \note Unlike many other components of the library, exact type of the attribute value
+ *       must be specified in the template parameter \c AttributeValueT. Type sequences
+ *       are not supported.
+ */
+template< typename MappedT, typename AttributeValueT = int >
+class basic_custom_mapping :
+    public basic_mapping< MappedT >
+{
+    //! Base type
+    typedef basic_mapping< MappedT > base_type;
+
+public:
+    //! Attribute contained value type
+    typedef AttributeValueT attribute_value_type;
+    //! Mapped value type
+    typedef typename base_type::mapped_type mapped_type;
+
+private:
+    //! \cond
+
+    //! Mapping type
+    typedef std::map< attribute_value_type, mapped_type > mapping_type;
+    //! Smart reference class for implementing insertion into the map
+    class reference_proxy;
+    friend class reference_proxy;
+    class reference_proxy
+    {
+        mapping_type& m_Mapping;
+        attribute_value_type m_Key;
+
+    public:
+        //! Constructor
+        reference_proxy(mapping_type& mapping, attribute_value_type const& key) : m_Mapping(mapping), m_Key(key) {}
+        //! Insertion
+        reference_proxy const& operator= (mapped_type const& val) const
+        {
+            m_Mapping[m_Key] = val;
+            return *this;
+        }
+    };
+
+    //! Attribute value visitor
+    struct visitor;
+    friend struct visitor;
+    struct visitor
+    {
+        typedef void result_type;
+
+        visitor(mapping_type const& mapping, mapped_type& extracted) :
+            m_Mapping(mapping),
+            m_Extracted(extracted)
+        {
+        }
+        template< typename T >
+        void operator() (T const& val) const
+        {
+            typename mapping_type::const_iterator it = m_Mapping.find(val);
+            if (it != m_Mapping.end())
+                m_Extracted = it->second;
+        }
+
+    private:
+        mapping_type const& m_Mapping;
+        mapped_type& m_Extracted;
+    };
+
+    //! \endcond
+
+private:
+    //! Attribute name
+    const attribute_name m_Name;
+    //! Visitor invoker for the attribute value
+    value_visitor_invoker< attribute_value_type > m_Invoker;
+    //! Default native value
+    mapped_type m_DefaultValue;
+    //! Conversion mapping
+    mapping_type m_Mapping;
+
+public:
+    /*!
+     * Constructor
+     *
+     * \param name Attribute name
+     * \param default_value The default native value that is returned if the conversion cannot be performed
+     */
+    explicit basic_custom_mapping(attribute_name const& name, mapped_type const& default_value) :
+        m_Name(name),
+        m_DefaultValue(default_value)
+    {
+    }
+    /*!
+     * Extraction operator. Extracts the attribute value and attempts to map it onto
+     * the native value.
+     *
+     * \param rec A log record to extract value from
+     * \return A mapped value, if mapping was successful, or the default value if
+     *         mapping did not succeed.
+     */
+    mapped_type operator() (record_view const& rec) const
+    {
+        mapped_type res = m_DefaultValue;
+        visitor vis(m_Mapping, res);
+        m_Invoker(m_Name, rec.attribute_values(), vis);
+        return res;
+    }
+    /*!
+     * Insertion operator
+     *
+     * \param key Attribute value to be mapped
+     * \return An object of unspecified type that allows to insert a new mapping through assignment.
+     *         The \a key argument becomes the key attribute value, and the assigned value becomes the
+     *         mapped native value.
+     */
+#ifndef BOOST_LOG_DOXYGEN_PASS
+    reference_proxy operator[] (attribute_value_type const& key)
+#else
+    implementation_defined operator[] (attribute_value_type const& key)
+#endif
+    {
+        return reference_proxy(m_Mapping, key);
+    }
+};
+
+} // namespace sinks
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#include <boost/log/detail/footer.hpp>
+
+#endif // BOOST_LOG_SINKS_ATTRIBUTE_MAPPING_HPP_INCLUDED_