817 lines
35 KiB
C++
817 lines
35 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 value_extraction.hpp
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* \author Andrey Semashev
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* \date 01.03.2008
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*
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* The header contains implementation of tools for extracting an attribute value
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* from the view.
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*/
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#ifndef BOOST_LOG_ATTRIBUTES_VALUE_EXTRACTION_HPP_INCLUDED_
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#define BOOST_LOG_ATTRIBUTES_VALUE_EXTRACTION_HPP_INCLUDED_
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#include <boost/mpl/vector.hpp>
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#include <boost/mpl/joint_view.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/identity.hpp>
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#include <boost/mpl/is_sequence.hpp>
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#include <boost/mpl/contains.hpp>
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#include <boost/mpl/push_back.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/core/enable_if.hpp>
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#include <boost/log/detail/config.hpp>
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#include <boost/log/exceptions.hpp>
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#include <boost/log/core/record.hpp>
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#include <boost/log/attributes/attribute_name.hpp>
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#include <boost/log/attributes/attribute_value.hpp>
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#include <boost/log/attributes/attribute.hpp>
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#include <boost/log/attributes/attribute_value_set.hpp>
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#include <boost/log/attributes/value_extraction_fwd.hpp>
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#include <boost/log/attributes/fallback_policy.hpp>
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#include <boost/log/expressions/keyword_fwd.hpp>
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#include <boost/log/utility/value_ref.hpp>
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#include <boost/log/utility/type_dispatch/static_type_dispatcher.hpp>
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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 result_of {
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/*!
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* \brief A metafunction that allows to acquire the result of the value extraction
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*
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* The metafunction results in a type that is in form of <tt>T const&</tt>, if \c T is
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* not an MPL type sequence and <tt>DefaultT</tt> is the same as <tt>T</tt>,
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* or <tt>value_ref< TypesT, TagT ></tt> otherwise, with
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* \c TypesT being a type sequence comprising the types from sequence \c T and \c DefaultT,
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* if it is not present in \c T already.
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*/
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template< typename T, typename DefaultT, typename TagT >
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struct extract_or_default
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{
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typedef typename mpl::eval_if<
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mpl::is_sequence< T >,
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mpl::eval_if<
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mpl::contains< T, DefaultT >,
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mpl::identity< T >,
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mpl::push_back< T, DefaultT >
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>,
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mpl::if_<
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is_same< T, DefaultT >,
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T,
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mpl::vector2< T, DefaultT >
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>
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>::type extracted_type;
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typedef typename mpl::if_<
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mpl::is_sequence< extracted_type >,
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value_ref< extracted_type, TagT >,
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extracted_type const&
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>::type type;
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};
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/*!
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* \brief A metafunction that allows to acquire the result of the value extraction
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*
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* The metafunction results in a type that is in form of <tt>T const&</tt>, if \c T is
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* not an MPL type sequence, or <tt>value_ref< T, TagT ></tt> otherwise. In the latter
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* case the value reference shall never be empty.
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*/
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template< typename T, typename TagT >
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struct extract_or_throw
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{
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typedef typename mpl::if_<
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mpl::is_sequence< T >,
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value_ref< T, TagT >,
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T const&
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>::type type;
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};
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/*!
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* \brief A metafunction that allows to acquire the result of the value extraction
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*
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* The metafunction results in a type that is in form of <tt>value_ref< T, TagT ></tt>.
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*/
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template< typename T, typename TagT >
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struct extract
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{
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typedef value_ref< T, TagT > type;
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};
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} // namespace result_of
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namespace aux {
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//! The function object initializes the value reference
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template< typename RefT >
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struct value_ref_initializer
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{
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typedef void result_type;
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value_ref_initializer(RefT& ref) : m_ref(ref)
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{
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}
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template< typename ArgT >
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result_type operator() (ArgT const& arg) const
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{
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m_ref = RefT(arg);
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}
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private:
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RefT& m_ref;
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};
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//! The function unwraps \c value_ref, if possible
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template< typename T, typename TagT >
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BOOST_FORCEINLINE typename boost::enable_if_c< mpl::is_sequence< T >::value, value_ref< T, TagT > >::type
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unwrap_value_ref(value_ref< T, TagT > const& r)
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{
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return r;
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}
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template< typename T, typename TagT >
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BOOST_FORCEINLINE typename boost::disable_if_c< mpl::is_sequence< T >::value, T const& >::type
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unwrap_value_ref(value_ref< T, TagT > const& r)
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{
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return r.get();
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}
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} // namespace aux
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/*!
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* \brief Generic attribute value extractor
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*
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* Attribute value extractor is a functional object that attempts to find and extract the stored
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* attribute value from the attribute values view or a log record. The extracted value is returned
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* from the extractor.
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*/
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template< typename T, typename FallbackPolicyT, typename TagT >
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class value_extractor :
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private FallbackPolicyT
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{
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public:
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//! Fallback policy
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typedef FallbackPolicyT fallback_policy;
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//! Attribute value types
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typedef T value_type;
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//! Function object result type
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typedef value_ref< value_type, TagT > result_type;
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public:
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/*!
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* Default constructor
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*/
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BOOST_DEFAULTED_FUNCTION(value_extractor(), {})
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/*!
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* Copy constructor
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*/
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value_extractor(value_extractor const& that) : fallback_policy(static_cast< fallback_policy const& >(that))
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{
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}
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/*!
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* Constructor
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*
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* \param arg Fallback policy constructor argument
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*/
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template< typename U >
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explicit value_extractor(U const& arg) : fallback_policy(arg) {}
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/*!
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* Extraction operator. Attempts to acquire the stored value of one of the supported types. If extraction succeeds,
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* the extracted value is returned.
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*
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* \param attr The attribute value to extract from.
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* \return The extracted value, if extraction succeeded, an empty value otherwise.
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*/
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result_type operator() (attribute_value const& attr) const
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{
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result_type res;
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aux::value_ref_initializer< result_type > initializer(res);
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if (!!attr)
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{
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static_type_dispatcher< value_type > disp(initializer);
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if (!attr.dispatch(disp) && !fallback_policy::apply_default(initializer))
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fallback_policy::on_invalid_type(attr.get_type());
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}
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else if (!fallback_policy::apply_default(initializer))
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{
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fallback_policy::on_missing_value();
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}
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return res;
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}
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/*!
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* Extraction operator. Looks for an attribute value with the specified name
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* and tries to acquire the stored value of one of the supported types. If extraction succeeds,
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* the extracted value is returned.
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*
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* \param name Attribute value name.
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* \param attrs A set of attribute values in which to look for the specified attribute value.
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* \return The extracted value, if extraction succeeded, an empty value otherwise.
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*/
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result_type operator() (attribute_name const& name, attribute_value_set const& attrs) const
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{
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try
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{
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attribute_value_set::const_iterator it = attrs.find(name);
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if (it != attrs.end())
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return operator() (it->second);
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else
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return operator() (attribute_value());
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}
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catch (exception& e)
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{
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// Attach the attribute name to the exception
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boost::log::aux::attach_attribute_name_info(e, name);
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throw;
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}
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}
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/*!
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* Extraction operator. Looks for an attribute value with the specified name
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* and tries to acquire the stored value of one of the supported types. If extraction succeeds,
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* the extracted value is returned.
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*
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* \param name Attribute value name.
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* \param rec A log record. The attribute value will be sought among those associated with the record.
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* \return The extracted value, if extraction succeeded, an empty value otherwise.
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*/
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result_type operator() (attribute_name const& name, record const& rec) const
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{
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return operator() (name, rec.attribute_values());
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}
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/*!
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* Extraction operator. Looks for an attribute value with the specified name
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* and tries to acquire the stored value of one of the supported types. If extraction succeeds,
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* the extracted value is returned.
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*
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* \param name Attribute value name.
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* \param rec A log record view. The attribute value will be sought among those associated with the record.
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* \return The extracted value, if extraction succeeded, an empty value otherwise.
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*/
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result_type operator() (attribute_name const& name, record_view const& rec) const
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{
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return operator() (name, rec.attribute_values());
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}
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/*!
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* \returns Fallback policy
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*/
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fallback_policy const& get_fallback_policy() const
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{
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return *static_cast< fallback_policy const* >(this);
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}
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};
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#if !defined(BOOST_LOG_DOXYGEN_PASS)
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#if !defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
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#define BOOST_LOG_AUX_VOID_DEFAULT = void
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#else
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#define BOOST_LOG_AUX_VOID_DEFAULT
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#endif
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#endif // !defined(BOOST_LOG_DOXYGEN_PASS)
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param name The name of the attribute value to extract.
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* \param attrs A set of attribute values in which to look for the specified attribute value.
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* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract< T, TagT >::type extract(attribute_name const& name, attribute_value_set const& attrs)
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{
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value_extractor< T, fallback_to_none, TagT > extractor;
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return extractor(name, attrs);
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param name The name of the attribute value to extract.
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* \param rec A log record. The attribute value will be sought among those associated with the record.
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* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract< T, TagT >::type extract(attribute_name const& name, record const& rec)
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{
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value_extractor< T, fallback_to_none, TagT > extractor;
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return extractor(name, rec);
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param name The name of the attribute value to extract.
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* \param rec A log record view. The attribute value will be sought among those associated with the record.
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* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract< T, TagT >::type extract(attribute_name const& name, record_view const& rec)
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{
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value_extractor< T, fallback_to_none, TagT > extractor;
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return extractor(name, rec);
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param value Attribute value.
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* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract< T, TagT >::type extract(attribute_value const& value)
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{
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value_extractor< T, fallback_to_none, TagT > extractor;
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return extractor(value);
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param name The name of the attribute value to extract.
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* \param attrs A set of attribute values in which to look for the specified attribute value.
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* \return The extracted value or a non-empty \c value_ref that refers to the value.
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* \throws An exception is thrown if the requested value cannot be extracted.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract_or_throw< T, TagT >::type extract_or_throw(attribute_name const& name, attribute_value_set const& attrs)
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{
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value_extractor< T, fallback_to_throw, TagT > extractor;
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return aux::unwrap_value_ref(extractor(name, attrs));
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param name The name of the attribute value to extract.
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* \param rec A log record. The attribute value will be sought among those associated with the record.
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* \return The extracted value or a non-empty \c value_ref that refers to the value.
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* \throws An exception is thrown if the requested value cannot be extracted.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract_or_throw< T, TagT >::type extract_or_throw(attribute_name const& name, record const& rec)
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{
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value_extractor< T, fallback_to_throw, TagT > extractor;
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return aux::unwrap_value_ref(extractor(name, rec));
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param name The name of the attribute value to extract.
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* \param rec A log record view. The attribute value will be sought among those associated with the record.
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* \return The extracted value or a non-empty \c value_ref that refers to the value.
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* \throws An exception is thrown if the requested value cannot be extracted.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract_or_throw< T, TagT >::type extract_or_throw(attribute_name const& name, record_view const& rec)
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{
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value_extractor< T, fallback_to_throw, TagT > extractor;
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return aux::unwrap_value_ref(extractor(name, rec));
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \param value Attribute value.
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* \return The extracted value or a non-empty \c value_ref that refers to the value.
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* \throws An exception is thrown if the requested value cannot be extracted.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT >
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inline typename result_of::extract_or_throw< T, TagT >::type extract_or_throw(attribute_value const& value)
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{
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value_extractor< T, fallback_to_throw, TagT > extractor;
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return aux::unwrap_value_ref(extractor(value));
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be extracted.
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*
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* \note Caution must be exercised if the default value is a temporary object. Because the function returns
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* a reference, if the temporary object is destroyed, the reference may become dangling.
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*
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* \param name The name of the attribute value to extract.
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* \param attrs A set of attribute values in which to look for the specified attribute value.
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* \param def_val The default value
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* \return The extracted value, if found. The default value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT, typename DefaultT >
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inline typename result_of::extract_or_default< T, DefaultT, TagT >::type
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extract_or_default(attribute_name const& name, attribute_value_set const& attrs, DefaultT const& def_val)
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{
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typedef typename result_of::extract_or_default< T, DefaultT, TagT >::extracted_type extracted_type;
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value_extractor< extracted_type, fallback_to_default< DefaultT const& >, TagT > extractor(def_val);
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return aux::unwrap_value_ref(extractor(name, attrs));
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be visited.
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*
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* \note Caution must be exercised if the default value is a temporary object. Because the function returns
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* a reference, if the temporary object is destroyed, the reference may become dangling.
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*
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* \param name The name of the attribute value to extract.
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* \param rec A log record. The attribute value will be sought among those associated with the record.
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* \param def_val The default value
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* \return The extracted value, if found. The default value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT, typename DefaultT >
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inline typename result_of::extract_or_default< T, DefaultT, TagT >::type
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extract_or_default(attribute_name const& name, record const& rec, DefaultT const& def_val)
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{
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typedef typename result_of::extract_or_default< T, DefaultT, TagT >::extracted_type extracted_type;
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value_extractor< extracted_type, fallback_to_default< DefaultT const& >, TagT > extractor(def_val);
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return aux::unwrap_value_ref(extractor(name, rec));
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}
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/*!
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* The function extracts an attribute value from the view. The user has to explicitly specify the
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* type or set of possible types of the attribute value to be visited.
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*
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* \note Caution must be exercised if the default value is a temporary object. Because the function returns
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* a reference, if the temporary object is destroyed, the reference may become dangling.
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*
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* \param name The name of the attribute value to extract.
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* \param rec A log record view. The attribute value will be sought among those associated with the record.
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* \param def_val The default value
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* \return The extracted value, if found. The default value otherwise.
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*/
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template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT, typename DefaultT >
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inline typename result_of::extract_or_default< T, DefaultT, TagT >::type
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extract_or_default(attribute_name const& name, record_view const& rec, DefaultT const& def_val)
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{
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|
typedef typename result_of::extract_or_default< T, DefaultT, TagT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& >, TagT > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(name, rec));
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be visited.
|
|
*
|
|
* \note Caution must be exercised if the default value is a temporary object. Because the function returns
|
|
* a reference, if the temporary object is destroyed, the reference may become dangling.
|
|
*
|
|
* \param value Attribute value.
|
|
* \param def_val The default value
|
|
* \return The extracted value, if found. The default value otherwise.
|
|
*/
|
|
template< typename T, typename TagT BOOST_LOG_AUX_VOID_DEFAULT, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT, TagT >::type extract_or_default(attribute_value const& value, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< T, DefaultT, TagT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& >, TagT > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(value));
|
|
}
|
|
|
|
#if defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract< T >::type extract(attribute_name const& name, attribute_value_set const& attrs)
|
|
{
|
|
value_extractor< T, fallback_to_none > extractor;
|
|
return extractor(name, attrs);
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract< T >::type extract(attribute_name const& name, record const& rec)
|
|
{
|
|
value_extractor< T, fallback_to_none > extractor;
|
|
return extractor(name, rec);
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract< T >::type extract(attribute_name const& name, record_view const& rec)
|
|
{
|
|
value_extractor< T, fallback_to_none > extractor;
|
|
return extractor(name, rec);
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract< T >::type extract(attribute_value const& value)
|
|
{
|
|
value_extractor< T, fallback_to_none > extractor;
|
|
return extractor(value);
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract_or_throw< T >::type extract_or_throw(attribute_name const& name, attribute_value_set const& attrs)
|
|
{
|
|
value_extractor< T, fallback_to_throw > extractor;
|
|
return aux::unwrap_value_ref(extractor(name, attrs));
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract_or_throw< T >::type extract_or_throw(attribute_name const& name, record const& rec)
|
|
{
|
|
value_extractor< T, fallback_to_throw > extractor;
|
|
return aux::unwrap_value_ref(extractor(name, rec));
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract_or_throw< T >::type extract_or_throw(attribute_name const& name, record_view const& rec)
|
|
{
|
|
value_extractor< T, fallback_to_throw > extractor;
|
|
return aux::unwrap_value_ref(extractor(name, rec));
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract_or_throw< T >::type extract_or_throw(attribute_value const& value)
|
|
{
|
|
value_extractor< T, fallback_to_throw > extractor;
|
|
return aux::unwrap_value_ref(extractor(value));
|
|
}
|
|
|
|
template< typename T, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT >::type extract_or_default(
|
|
attribute_name const& name, attribute_value_set const& attrs, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< T, DefaultT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& > > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(name, attrs));
|
|
}
|
|
|
|
template< typename T, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT >::type extract_or_default(
|
|
attribute_name const& name, record const& rec, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< T, DefaultT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& > > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(name, rec));
|
|
}
|
|
|
|
template< typename T, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT >::type extract_or_default(
|
|
attribute_name const& name, record_view const& rec, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< T, DefaultT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& > > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(name, rec));
|
|
}
|
|
|
|
template< typename T, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT >::type extract_or_default(attribute_value const& value, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< T, DefaultT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& > > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(value));
|
|
}
|
|
|
|
#endif // defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param attrs A set of attribute values in which to look for the specified attribute value.
|
|
* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT >
|
|
inline typename result_of::extract< typename DescriptorT::value_type, DescriptorT >::type
|
|
extract(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, attribute_value_set const& attrs)
|
|
{
|
|
value_extractor< typename DescriptorT::value_type, fallback_to_none, DescriptorT > extractor;
|
|
return extractor(keyword.get_name(), attrs);
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param rec A log record. The attribute value will be sought among those associated with the record.
|
|
* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT >
|
|
inline typename result_of::extract< typename DescriptorT::value_type, DescriptorT >::type
|
|
extract(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, record const& rec)
|
|
{
|
|
value_extractor< typename DescriptorT::value_type, fallback_to_none, DescriptorT > extractor;
|
|
return extractor(keyword.get_name(), rec);
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param rec A log record view. The attribute value will be sought among those associated with the record.
|
|
* \return A \c value_ref that refers to the extracted value, if found. An empty value otherwise.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT >
|
|
inline typename result_of::extract< typename DescriptorT::value_type, DescriptorT >::type
|
|
extract(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, record_view const& rec)
|
|
{
|
|
value_extractor< typename DescriptorT::value_type, fallback_to_none, DescriptorT > extractor;
|
|
return extractor(keyword.get_name(), rec);
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param attrs A set of attribute values in which to look for the specified attribute value.
|
|
* \return The extracted value or a non-empty \c value_ref that refers to the value.
|
|
* \throws An exception is thrown if the requested value cannot be extracted.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT >
|
|
inline typename result_of::extract_or_throw< typename DescriptorT::value_type, DescriptorT >::type
|
|
extract_or_throw(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, attribute_value_set const& attrs)
|
|
{
|
|
value_extractor< typename DescriptorT::value_type, fallback_to_throw, DescriptorT > extractor;
|
|
return aux::unwrap_value_ref(extractor(keyword.get_name(), attrs));
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param rec A log record. The attribute value will be sought among those associated with the record.
|
|
* \return The extracted value or a non-empty \c value_ref that refers to the value.
|
|
* \throws An exception is thrown if the requested value cannot be extracted.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT >
|
|
inline typename result_of::extract_or_throw< typename DescriptorT::value_type, DescriptorT >::type
|
|
extract_or_throw(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, record const& rec)
|
|
{
|
|
value_extractor< typename DescriptorT::value_type, fallback_to_throw, DescriptorT > extractor;
|
|
return aux::unwrap_value_ref(extractor(keyword.get_name(), rec));
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param rec A log record view. The attribute value will be sought among those associated with the record.
|
|
* \return The extracted value or a non-empty \c value_ref that refers to the value.
|
|
* \throws An exception is thrown if the requested value cannot be extracted.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT >
|
|
inline typename result_of::extract_or_throw< typename DescriptorT::value_type, DescriptorT >::type
|
|
extract_or_throw(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, record_view const& rec)
|
|
{
|
|
value_extractor< typename DescriptorT::value_type, fallback_to_throw, DescriptorT > extractor;
|
|
return aux::unwrap_value_ref(extractor(keyword.get_name(), rec));
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be extracted.
|
|
*
|
|
* \note Caution must be exercised if the default value is a temporary object. Because the function returns
|
|
* a reference, if the temporary object is destroyed, the reference may become dangling.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param attrs A set of attribute values in which to look for the specified attribute value.
|
|
* \param def_val The default value
|
|
* \return The extracted value, if found. The default value otherwise.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT, typename DefaultT >
|
|
inline typename result_of::extract_or_default< typename DescriptorT::value_type, DefaultT, DescriptorT >::type
|
|
extract_or_default(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, attribute_value_set const& attrs, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< typename DescriptorT::value_type, DefaultT, DescriptorT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& >, DescriptorT > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(keyword.get_name(), attrs));
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be visited.
|
|
*
|
|
* \note Caution must be exercised if the default value is a temporary object. Because the function returns
|
|
* a reference, if the temporary object is destroyed, the reference may become dangling.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param rec A log record. The attribute value will be sought among those associated with the record.
|
|
* \param def_val The default value
|
|
* \return The extracted value, if found. The default value otherwise.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT, typename DefaultT >
|
|
inline typename result_of::extract_or_default< typename DescriptorT::value_type, DefaultT, DescriptorT >::type
|
|
extract_or_default(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, record const& rec, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< typename DescriptorT::value_type, DefaultT, DescriptorT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& >, DescriptorT > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(keyword.get_name(), rec));
|
|
}
|
|
|
|
/*!
|
|
* The function extracts an attribute value from the view. The user has to explicitly specify the
|
|
* type or set of possible types of the attribute value to be visited.
|
|
*
|
|
* \note Caution must be exercised if the default value is a temporary object. Because the function returns
|
|
* a reference, if the temporary object is destroyed, the reference may become dangling.
|
|
*
|
|
* \param keyword The keyword of the attribute value to extract.
|
|
* \param rec A log record view. The attribute value will be sought among those associated with the record.
|
|
* \param def_val The default value
|
|
* \return The extracted value, if found. The default value otherwise.
|
|
*/
|
|
template< typename DescriptorT, template< typename > class ActorT, typename DefaultT >
|
|
inline typename result_of::extract_or_default< typename DescriptorT::value_type, DefaultT, DescriptorT >::type
|
|
extract_or_default(expressions::attribute_keyword< DescriptorT, ActorT > const& keyword, record_view const& rec, DefaultT const& def_val)
|
|
{
|
|
typedef typename result_of::extract_or_default< typename DescriptorT::value_type, DefaultT, DescriptorT >::extracted_type extracted_type;
|
|
value_extractor< extracted_type, fallback_to_default< DefaultT const& >, DescriptorT > extractor(def_val);
|
|
return aux::unwrap_value_ref(extractor(keyword.get_name(), rec));
|
|
}
|
|
|
|
#if !defined(BOOST_LOG_DOXYGEN_PASS)
|
|
|
|
template< typename T, typename TagT >
|
|
inline typename result_of::extract< T, TagT >::type attribute_value::extract() const
|
|
{
|
|
return boost::log::extract< T, TagT >(*this);
|
|
}
|
|
|
|
template< typename T, typename TagT >
|
|
inline typename result_of::extract_or_throw< T, TagT >::type attribute_value::extract_or_throw() const
|
|
{
|
|
return boost::log::extract_or_throw< T, TagT >(*this);
|
|
}
|
|
|
|
template< typename T, typename TagT >
|
|
inline typename result_of::extract_or_default< T, T, TagT >::type attribute_value::extract_or_default(T const& def_value) const
|
|
{
|
|
return boost::log::extract_or_default< T, TagT >(*this, def_value);
|
|
}
|
|
|
|
template< typename T, typename TagT, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT, TagT >::type attribute_value::extract_or_default(DefaultT const& def_value) const
|
|
{
|
|
return boost::log::extract_or_default< T, TagT >(*this, def_value);
|
|
}
|
|
|
|
#if defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract< T >::type attribute_value::extract() const
|
|
{
|
|
return boost::log::extract< T >(*this);
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract_or_throw< T >::type attribute_value::extract_or_throw() const
|
|
{
|
|
return boost::log::extract_or_throw< T >(*this);
|
|
}
|
|
|
|
template< typename T >
|
|
inline typename result_of::extract_or_default< T, T >::type attribute_value::extract_or_default(T const& def_value) const
|
|
{
|
|
return boost::log::extract_or_default< T >(*this, def_value);
|
|
}
|
|
|
|
template< typename T, typename DefaultT >
|
|
inline typename result_of::extract_or_default< T, DefaultT >::type attribute_value::extract_or_default(DefaultT const& def_value) const
|
|
{
|
|
return boost::log::extract_or_default< T >(*this, def_value);
|
|
}
|
|
|
|
#endif // defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS)
|
|
|
|
#endif // !defined(BOOST_LOG_DOXYGEN_PASS)
|
|
|
|
#undef BOOST_LOG_AUX_VOID_DEFAULT
|
|
|
|
BOOST_LOG_CLOSE_NAMESPACE // namespace log
|
|
|
|
} // namespace boost
|
|
|
|
#include <boost/log/detail/footer.hpp>
|
|
|
|
#endif // BOOST_LOG_ATTRIBUTES_VALUE_EXTRACTION_HPP_INCLUDED_
|