| /* |
| * 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_ |