142 lines
4.0 KiB
C++
142 lines
4.0 KiB
C++
/*
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* Copyright Andrey Semashev 2007 - 2015.
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*/
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/*!
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* \file attribute_value_impl.hpp
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* \author Andrey Semashev
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* \date 24.06.2007
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*
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* The header contains an implementation of a basic attribute value implementation class.
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*/
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#ifndef BOOST_LOG_ATTRIBUTES_ATTRIBUTE_VALUE_IMPL_HPP_INCLUDED_
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#define BOOST_LOG_ATTRIBUTES_ATTRIBUTE_VALUE_IMPL_HPP_INCLUDED_
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#include <boost/type_index.hpp>
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#include <boost/move/core.hpp>
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#include <boost/move/utility_core.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_traits/is_nothrow_move_constructible.hpp>
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#include <boost/log/detail/config.hpp>
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#include <boost/log/attributes/attribute_value.hpp>
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#include <boost/log/utility/type_dispatch/type_dispatcher.hpp>
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#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
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#include <boost/type_traits/remove_reference.hpp>
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#endif
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#include <boost/log/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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BOOST_LOG_OPEN_NAMESPACE
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namespace attributes {
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/*!
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* \brief Basic attribute value implementation class
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*
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* This class can be used as a boilerplate for simple attribute values. The class implements all needed
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* interfaces of attribute values and allows to store a single value of the type specified as a template parameter.
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* The stored value can be dispatched with type dispatching mechanism.
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*/
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template< typename T >
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class attribute_value_impl :
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public attribute_value::impl
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{
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public:
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//! Value type
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typedef T value_type;
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private:
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//! Attribute value
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const value_type m_value;
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public:
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/*!
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* Constructor with initialization of the stored value
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*/
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explicit attribute_value_impl(value_type const& v) : m_value(v) {}
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/*!
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* Constructor with initialization of the stored value
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*/
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explicit attribute_value_impl(BOOST_RV_REF(value_type) v) BOOST_NOEXCEPT_IF(boost::is_nothrow_move_constructible< value_type >::value) :
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m_value(boost::move(v))
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{
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}
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/*!
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* Attribute value dispatching method.
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*
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* \param dispatcher The dispatcher that receives the stored value
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*
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* \return \c true if the value has been dispatched, \c false otherwise
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*/
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bool dispatch(type_dispatcher& dispatcher) BOOST_OVERRIDE
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{
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type_dispatcher::callback< value_type > callback = dispatcher.get_callback< value_type >();
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if (callback)
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{
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callback(m_value);
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return true;
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}
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else
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return false;
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}
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/*!
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* \return The attribute value type
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*/
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typeindex::type_index get_type() const BOOST_OVERRIDE { return typeindex::type_id< value_type >(); }
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/*!
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* \return Reference to the contained value.
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*/
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value_type const& get() const { return m_value; }
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};
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/*!
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* The function creates an attribute value from the specified object.
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*/
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#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
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template< typename T >
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inline attribute_value make_attribute_value(T&& v)
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{
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typedef typename remove_cv< typename remove_reference< T >::type >::type value_type;
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return attribute_value(new attribute_value_impl< value_type >(boost::forward< T >(v)));
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}
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#else // !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
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template< typename T >
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inline attribute_value make_attribute_value(T const& v)
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{
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typedef typename remove_cv< T >::type value_type;
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return attribute_value(new attribute_value_impl< value_type >(v));
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}
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template< typename T >
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inline attribute_value make_attribute_value(rv< T > const& v)
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{
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typedef typename remove_cv< T >::type value_type;
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return attribute_value(new attribute_value_impl< value_type >(v));
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}
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#endif // !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
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} // namespace attributes
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BOOST_LOG_CLOSE_NAMESPACE // namespace log
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} // namespace boost
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#include <boost/log/detail/footer.hpp>
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#endif // BOOST_LOG_ATTRIBUTES_ATTRIBUTE_VALUE_IMPL_HPP_INCLUDED_
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