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+/*
+ * Copyright Andrey Semashev 2007 - 2014.
+ * 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_value_impl.hpp
+ * \author Andrey Semashev
+ * \date 24.06.2007
+ *
+ * The header contains an implementation of a basic attribute value implementation class.
+ */
+
+#ifndef BOOST_LOG_ATTRIBUTES_ATTRIBUTE_VALUE_IMPL_HPP_INCLUDED_
+#define BOOST_LOG_ATTRIBUTES_ATTRIBUTE_VALUE_IMPL_HPP_INCLUDED_
+
+#include <boost/move/core.hpp>
+#include <boost/move/utility.hpp>
+#include <boost/type_traits/remove_cv.hpp>
+#include <boost/log/detail/config.hpp>
+#include <boost/log/attributes/attribute_value.hpp>
+#include <boost/log/utility/type_dispatch/type_dispatcher.hpp>
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+#include <boost/type_traits/remove_reference.hpp>
+#endif
+#include <boost/log/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+BOOST_LOG_OPEN_NAMESPACE
+
+namespace attributes {
+
+/*!
+ * \brief Basic attribute value implementation class
+ *
+ * This class can be used as a boilerplate for simple attribute values. The class implements all needed
+ * interfaces of attribute values and allows to store a single value of the type specified as a template parameter.
+ * The stored value can be dispatched with type dispatching mechanism.
+ */
+template< typename T >
+class attribute_value_impl :
+ public attribute_value::impl
+{
+public:
+ //! Value type
+ typedef T value_type;
+
+private:
+ //! Attribute value
+ const value_type m_value;
+
+public:
+ /*!
+ * Constructor with initialization of the stored value
+ */
+ explicit attribute_value_impl(value_type const& v) : m_value(v) {}
+ /*!
+ * Constructor with initialization of the stored value
+ */
+ explicit attribute_value_impl(BOOST_RV_REF(value_type) v) : m_value(v) {}
+
+ /*!
+ * Attribute value dispatching method.
+ *
+ * \param dispatcher The dispatcher that receives the stored value
+ *
+ * \return \c true if the value has been dispatched, \c false otherwise
+ */
+ virtual bool dispatch(type_dispatcher& dispatcher)
+ {
+ type_dispatcher::callback< value_type > callback = dispatcher.get_callback< value_type >();
+ if (callback)
+ {
+ callback(m_value);
+ return true;
+ }
+ else
+ return false;
+ }
+
+ /*!
+ * \return The attribute value type
+ */
+ type_info_wrapper get_type() const { return type_info_wrapper(typeid(value_type)); }
+
+ /*!
+ * \return Reference to the contained value.
+ */
+ value_type const& get() const { return m_value; }
+};
+
+/*!
+ * The function creates an attribute value from the specified object.
+ */
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+
+template< typename T >
+inline attribute_value make_attribute_value(T&& v)
+{
+ typedef typename remove_cv< typename remove_reference< T >::type >::type value_type;
+ return attribute_value(new attribute_value_impl< value_type >(boost::forward< T >(v)));
+}
+
+#else // !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+
+template< typename T >
+inline attribute_value make_attribute_value(T const& v)
+{
+ typedef typename remove_cv< T >::type value_type;
+ return attribute_value(new attribute_value_impl< value_type >(v));
+}
+
+template< typename T >
+inline attribute_value make_attribute_value(rv< T > const& v)
+{
+ typedef typename remove_cv< T >::type value_type;
+ return attribute_value(new attribute_value_impl< value_type >(v));
+}
+
+#endif // !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+
+} // namespace attributes
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#include <boost/log/detail/footer.hpp>
+
+#endif // BOOST_LOG_ATTRIBUTES_ATTRIBUTE_VALUE_IMPL_HPP_INCLUDED_