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- /*
- * Copyright Andrey Semashev 2007 - 2015.
- * 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 add_value.hpp
- * \author Andrey Semashev
- * \date 26.11.2012
- *
- * This header contains the \c add_value manipulator.
- */
- #ifndef BOOST_LOG_UTILITY_MANIPULATORS_ADD_VALUE_HPP_INCLUDED_
- #define BOOST_LOG_UTILITY_MANIPULATORS_ADD_VALUE_HPP_INCLUDED_
- #include <boost/mpl/if.hpp>
- #include <boost/type_traits/is_scalar.hpp>
- #include <boost/type_traits/remove_cv.hpp>
- #include <boost/type_traits/remove_reference.hpp>
- #include <boost/log/detail/config.hpp>
- #include <boost/log/detail/embedded_string_type.hpp>
- #include <boost/log/attributes/attribute_name.hpp>
- #include <boost/log/attributes/attribute_value_impl.hpp>
- #include <boost/log/expressions/keyword_fwd.hpp>
- #include <boost/log/sources/record_ostream.hpp>
- #include <boost/log/detail/header.hpp>
- #ifdef BOOST_HAS_PRAGMA_ONCE
- #pragma once
- #endif
- #ifdef _MSC_VER
- #pragma warning(push)
- // 'boost::log::v2s_mt_nt6::add_value_manip<RefT>::m_value' : reference member is initialized to a temporary that doesn't persist after the constructor exits
- // This is intentional since the manipulator can be used with a temporary, which will be used before the streaming expression ends and it is destroyed.
- #pragma warning(disable: 4413)
- // returning address of local variable or temporary
- // This warning refers to add_value_manip<RefT>::get_value() when RefT is an rvalue reference. We store the reference in the manipulator and we intend to return it as is.
- #pragma warning(disable: 4172)
- #endif
- namespace boost {
- BOOST_LOG_OPEN_NAMESPACE
- //! Attribute value manipulator
- template< typename RefT >
- class add_value_manip
- {
- public:
- //! Stored reference type
- typedef RefT reference_type;
- //! Attribute value type
- typedef typename remove_cv< typename remove_reference< reference_type >::type >::type value_type;
- private:
- // The stored reference type is an lvalue reference since apparently different compilers (GCC and MSVC) have different quirks when rvalue references are stored as members.
- // Additionally, MSVC (at least 11.0) has a bug which causes a dangling reference to be stored in the manipulator, if a scalar rvalue is passed to the add_value generator.
- // To work around this problem we save the value inside the manipulator in this case.
- typedef typename remove_reference< reference_type >::type& lvalue_reference_type;
- typedef typename mpl::if_<
- is_scalar< value_type >,
- value_type,
- lvalue_reference_type
- >::type stored_type;
- typedef typename mpl::if_<
- is_scalar< value_type >,
- value_type,
- reference_type
- >::type get_value_result_type;
- private:
- //! Attribute value
- stored_type m_value;
- //! Attribute name
- attribute_name m_name;
- public:
- //! Initializing constructor
- add_value_manip(attribute_name const& name, reference_type value) : m_value(static_cast< lvalue_reference_type >(value)), m_name(name)
- {
- }
- //! Returns attribute name
- attribute_name get_name() const { return m_name; }
- //! Returns attribute value
- get_value_result_type get_value() const { return static_cast< get_value_result_type >(m_value); }
- };
- //! The operator attaches an attribute value to the log record
- template< typename CharT, typename RefT >
- inline basic_record_ostream< CharT >& operator<< (basic_record_ostream< CharT >& strm, add_value_manip< RefT > const& manip)
- {
- typedef typename aux::make_embedded_string_type< typename add_value_manip< RefT >::value_type >::type value_type;
- attribute_value value(new attributes::attribute_value_impl< value_type >(manip.get_value()));
- strm.get_record().attribute_values().insert(manip.get_name(), value);
- return strm;
- }
- //! The function creates a manipulator that attaches an attribute value to a log record
- #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
- template< typename T >
- inline add_value_manip< T&& > add_value(attribute_name const& name, T&& value)
- {
- return add_value_manip< T&& >(name, static_cast< T&& >(value));
- }
- //! \overload
- template< typename DescriptorT, template< typename > class ActorT >
- inline add_value_manip< typename DescriptorT::value_type&& >
- add_value(expressions::attribute_keyword< DescriptorT, ActorT > const&, typename DescriptorT::value_type&& value)
- {
- typedef typename DescriptorT::value_type value_type;
- return add_value_manip< value_type&& >(DescriptorT::get_name(), static_cast< value_type&& >(value));
- }
- //! \overload
- template< typename DescriptorT, template< typename > class ActorT >
- inline add_value_manip< typename DescriptorT::value_type& >
- add_value(expressions::attribute_keyword< DescriptorT, ActorT > const&, typename DescriptorT::value_type& value)
- {
- return add_value_manip< typename DescriptorT::value_type& >(DescriptorT::get_name(), value);
- }
- //! \overload
- template< typename DescriptorT, template< typename > class ActorT >
- inline add_value_manip< typename DescriptorT::value_type const& >
- add_value(expressions::attribute_keyword< DescriptorT, ActorT > const&, typename DescriptorT::value_type const& value)
- {
- return add_value_manip< typename DescriptorT::value_type const& >(DescriptorT::get_name(), value);
- }
- #else // !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
- template< typename T >
- inline add_value_manip< T const& > add_value(attribute_name const& name, T const& value)
- {
- return add_value_manip< T const& >(name, value);
- }
- template< typename DescriptorT, template< typename > class ActorT >
- inline add_value_manip< typename DescriptorT::value_type const& >
- add_value(expressions::attribute_keyword< DescriptorT, ActorT > const&, typename DescriptorT::value_type const& value)
- {
- return add_value_manip< typename DescriptorT::value_type const& >(DescriptorT::get_name(), value);
- }
- #endif // !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
- BOOST_LOG_CLOSE_NAMESPACE // namespace log
- } // namespace boost
- #ifdef _MSC_VER
- #pragma warning(pop)
- #endif
- #include <boost/log/detail/footer.hpp>
- #endif // BOOST_LOG_UTILITY_MANIPULATORS_ADD_VALUE_HPP_INCLUDED_
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