Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   keyword.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   29.01.2012
Chris@16:  *
Chris@16:  * The header contains attribute keyword declaration.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_EXPRESSIONS_KEYWORD_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_EXPRESSIONS_KEYWORD_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/ref.hpp>
Chris@16: #include <boost/proto/extends.hpp>
Chris@16: #include <boost/proto/make_expr.hpp>
Chris@16: #include <boost/phoenix/core/actor.hpp>
Chris@16: #include <boost/phoenix/core/domain.hpp>
Chris@16: #include <boost/phoenix/core/environment.hpp>
Chris@16: #include <boost/fusion/sequence/intrinsic/at.hpp>
Chris@16: #include <boost/preprocessor/cat.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/detail/custom_terminal_spec.hpp>
Chris@16: #include <boost/log/expressions/keyword_fwd.hpp>
Chris@16: #include <boost/log/expressions/is_keyword_descriptor.hpp>
Chris@16: #include <boost/log/expressions/attr.hpp>
Chris@16: #include <boost/log/attributes/attribute_name.hpp>
Chris@16: #include <boost/log/attributes/value_extraction.hpp>
Chris@16: #include <boost/log/attributes/fallback_policy.hpp>
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace expressions {
Chris@16: 
Chris@16: /*!
Chris@16:  * This class implements an expression template keyword. It is used to start template expressions involving attribute values.
Chris@16:  */
Chris@16: template< typename DescriptorT, template< typename > class ActorT >
Chris@16: struct attribute_keyword
Chris@16: {
Chris@16:     //! Self type
Chris@16:     typedef attribute_keyword this_type;
Chris@16:     //! Attribute descriptor type
Chris@16:     typedef DescriptorT descriptor_type;
Chris@16: 
Chris@16:     BOOST_PROTO_BASIC_EXTENDS(typename proto::terminal< descriptor_type >::type, this_type, phoenix::phoenix_domain)
Chris@16: 
Chris@16:     //! Attribute value type
Chris@16:     typedef typename descriptor_type::value_type value_type;
Chris@16: 
Chris@16:     //! Returns attribute name
Chris@16:     static attribute_name get_name() { return descriptor_type::get_name(); }
Chris@16: 
Chris@16:     //! Expression with cached attribute name
Chris@16:     typedef attribute_actor<
Chris@16:         value_type,
Chris@16:         fallback_to_none,
Chris@16:         descriptor_type,
Chris@16:         ActorT
Chris@16:     > or_none_result_type;
Chris@16: 
Chris@16:     //! Generates an expression that extracts the attribute value or a default value
Chris@16:     static or_none_result_type or_none()
Chris@16:     {
Chris@16:         typedef typename or_none_result_type::terminal_type result_terminal;
Chris@16:         typename or_none_result_type::base_type act = {{ result_terminal(get_name()) }};
Chris@16:         return or_none_result_type(act);
Chris@16:     }
Chris@16: 
Chris@16:     //! Expression with cached attribute name
Chris@16:     typedef attribute_actor<
Chris@16:         value_type,
Chris@16:         fallback_to_throw,
Chris@16:         descriptor_type,
Chris@16:         ActorT
Chris@16:     > or_throw_result_type;
Chris@16: 
Chris@16:     //! Generates an expression that extracts the attribute value or throws an exception
Chris@16:     static or_throw_result_type or_throw()
Chris@16:     {
Chris@16:         typedef typename or_throw_result_type::terminal_type result_terminal;
Chris@16:         typename or_throw_result_type::base_type act = {{ result_terminal(get_name()) }};
Chris@16:         return or_throw_result_type(act);
Chris@16:     }
Chris@16: 
Chris@16:     //! Generates an expression that extracts the attribute value or a default value
Chris@16:     template< typename DefaultT >
Chris@16:     static attribute_actor<
Chris@16:         value_type,
Chris@16:         fallback_to_default< DefaultT >,
Chris@16:         descriptor_type,
Chris@16:         ActorT
Chris@16:     > or_default(DefaultT const& def_val)
Chris@16:     {
Chris@16:         typedef attribute_actor<
Chris@16:             value_type,
Chris@16:             fallback_to_default< DefaultT >,
Chris@16:             descriptor_type,
Chris@16:             ActorT
Chris@16:         > or_default_result_type;
Chris@16:         typedef typename or_default_result_type::terminal_type result_terminal;
Chris@16:         typename or_default_result_type::base_type act = {{ result_terminal(get_name(), def_val) }};
Chris@16:         return or_default_result_type(act);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } // namespace expressions
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: #ifndef BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: namespace proto {
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: // This hack is needed in order to cache attribute name into the expression terminal when the template
Chris@16: // expression is constructed. The standard way through a custom domain doesn't work because phoenix::actor
Chris@16: // is bound to phoenix_domain.
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16:     typedef boost::log::expressions::attribute_keyword< DescriptorT, ActorT > keyword_type;
Chris@16:     typedef typename keyword_type::or_none_result_type result_type;
Chris@16: 
Chris@16:     result_type operator() (keyword_type const& keyword) const
Chris@16:     {
Chris@16:         return keyword.or_none();
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >&, DomainT > :
Chris@16:     public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT > const&, DomainT > :
Chris@16:     public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::reference_wrapper< boost::log::expressions::attribute_keyword< DescriptorT, ActorT > >, DomainT > :
Chris@16:     public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::reference_wrapper< boost::log::expressions::attribute_keyword< DescriptorT, ActorT > > const, DomainT > :
Chris@16:     public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::reference_wrapper< const boost::log::expressions::attribute_keyword< DescriptorT, ActorT > >, DomainT > :
Chris@16:     public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename DescriptorT, template< typename > class ActorT, typename DomainT >
Chris@16: struct protoify< boost::reference_wrapper< const boost::log::expressions::attribute_keyword< DescriptorT, ActorT > > const, DomainT > :
Chris@16:     public protoify< boost::log::expressions::attribute_keyword< DescriptorT, ActorT >, DomainT >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace proto
Chris@16: 
Chris@16: #endif // !defined(BOOST_LOG_DOXYGEN_PASS)
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #ifndef BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: #define BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE_IMPL(keyword_, name_, value_type_, tag_ns_)\
Chris@16:     namespace tag_ns_\
Chris@16:     {\
Chris@16:         struct keyword_ :\
Chris@16:             public ::boost::log::expressions::keyword_descriptor\
Chris@16:         {\
Chris@16:             typedef value_type_ value_type;\
Chris@16:             static ::boost::log::attribute_name get_name() { return ::boost::log::attribute_name(name_); }\
Chris@16:         };\
Chris@16:     }\
Chris@16:     typedef ::boost::log::expressions::attribute_keyword< tag_ns_::keyword_ > BOOST_PP_CAT(keyword_, _type);
Chris@16: 
Chris@16: #define BOOST_LOG_ATTRIBUTE_KEYWORD_IMPL(keyword_, name_, value_type_, tag_ns_)\
Chris@16:     BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE_IMPL(keyword_, name_, value_type_, tag_ns_)\
Chris@16:     const BOOST_PP_CAT(keyword_, _type) keyword_ = {};
Chris@16: 
Chris@16: #endif // BOOST_LOG_DOXYGEN_PASS
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief The macro declares an attribute keyword type
Chris@16:  *
Chris@16:  * The macro should be used at a namespace scope. It expands into an attribute keyword type definition, including the
Chris@16:  * \c tag namespace and the keyword tag type within which has the following layout:
Chris@16:  *
Chris@16:  * \code
Chris@16:  * namespace tag
Chris@16:  * {
Chris@16:  *   struct keyword_ :
Chris@16:  *     public boost::log::expressions::keyword_descriptor
Chris@16:  *   {
Chris@16:  *     typedef value_type_ value_type;
Chris@16:  *     static boost::log::attribute_name get_name();
Chris@16:  *   };
Chris@16:  * }
Chris@16:  *
Chris@16:  * typedef boost::log::expressions::attribute_keyword< tag::keyword_ > keyword_type;
Chris@16:  * \endcode
Chris@16:  *
Chris@16:  * The \c get_name method returns the attribute name.
Chris@16:  *
Chris@16:  * \note This macro only defines the type of the keyword. To also define the keyword object, use
Chris@16:  *       the \c BOOST_LOG_ATTRIBUTE_KEYWORD macro instead.
Chris@16:  *
Chris@16:  * \param keyword_ Keyword name
Chris@16:  * \param name_ Attribute name string
Chris@16:  * \param value_type_ Attribute value type
Chris@16:  */
Chris@16: #define BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE(keyword_, name_, value_type_)\
Chris@16:     BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE_IMPL(keyword_, name_, value_type_, tag)
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief The macro declares an attribute keyword
Chris@16:  *
Chris@16:  * The macro provides definitions similar to \c BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE and additionally
Chris@16:  * defines the keyword object.
Chris@16:  *
Chris@16:  * \param keyword_ Keyword name
Chris@16:  * \param name_ Attribute name string
Chris@16:  * \param value_type_ Attribute value type
Chris@16:  */
Chris@16: #define BOOST_LOG_ATTRIBUTE_KEYWORD(keyword_, name_, value_type_)\
Chris@16:     BOOST_LOG_ATTRIBUTE_KEYWORD_IMPL(keyword_, name_, value_type_, tag)
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #if defined(BOOST_LOG_TRIVIAL_HPP_INCLUDED_)
Chris@16: #include <boost/log/detail/trivial_keyword.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: #endif // BOOST_LOG_EXPRESSIONS_KEYWORD_HPP_INCLUDED_