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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 static_type_dispatcher.hpp
- * \author Andrey Semashev
- * \date 15.04.2007
- *
- * The header contains implementation of a compile-time type dispatcher.
- */
- #ifndef BOOST_LOG_STATIC_TYPE_DISPATCHER_HPP_INCLUDED_
- #define BOOST_LOG_STATIC_TYPE_DISPATCHER_HPP_INCLUDED_
- #include <cstddef>
- #include <utility>
- #include <iterator>
- #include <algorithm>
- #include <boost/array.hpp>
- #include <boost/static_assert.hpp>
- #include <boost/type_index.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/mpl/size.hpp>
- #include <boost/mpl/begin.hpp>
- #include <boost/mpl/end.hpp>
- #include <boost/mpl/deref.hpp>
- #include <boost/mpl/next.hpp>
- #include <boost/mpl/is_sequence.hpp>
- #include <boost/core/addressof.hpp>
- #include <boost/log/detail/config.hpp>
- #include <boost/log/utility/once_block.hpp>
- #include <boost/log/utility/type_dispatch/type_dispatcher.hpp>
- #include <boost/log/detail/header.hpp>
- #ifdef BOOST_HAS_PRAGMA_ONCE
- #pragma once
- #endif
- namespace boost {
- BOOST_LOG_OPEN_NAMESPACE
- namespace aux {
- //! Ordering predicate for type dispatching map
- struct dispatching_map_order
- {
- typedef bool result_type;
- typedef std::pair< typeindex::type_index, void* > first_argument_type, second_argument_type;
- result_type operator() (first_argument_type const& left, second_argument_type const& right) const
- {
- return (left.first < right.first);
- }
- };
- //! Dispatching map filler
- template< typename VisitorT >
- struct dispatching_map_initializer
- {
- template< typename IteratorT >
- static BOOST_FORCEINLINE void init(IteratorT*, IteratorT*, std::pair< typeindex::type_index, void* >*)
- {
- }
- template< typename BeginIteratorT, typename EndIteratorT >
- static BOOST_FORCEINLINE void init(BeginIteratorT*, EndIteratorT* end, std::pair< typeindex::type_index, void* >* p)
- {
- typedef typename mpl::deref< BeginIteratorT >::type type;
- do_init(static_cast< type* >(0), p);
- typedef typename mpl::next< BeginIteratorT >::type next_iterator_type;
- init(static_cast< next_iterator_type* >(0), end, p + 1);
- }
- private:
- template< typename T >
- static BOOST_FORCEINLINE void do_init(T*, std::pair< typeindex::type_index, void* >* p)
- {
- p->first = typeindex::type_id< T >();
- typedef void (*trampoline_t)(void*, T const&);
- BOOST_STATIC_ASSERT_MSG(sizeof(trampoline_t) == sizeof(void*), "Boost.Log: Unsupported platform, the size of a function pointer differs from the size of a pointer");
- union
- {
- void* as_pvoid;
- trampoline_t as_trampoline;
- }
- caster;
- caster.as_trampoline = (trampoline_t)&type_dispatcher::callback_base::trampoline< VisitorT, T >;
- p->second = caster.as_pvoid;
- }
- };
- //! A base class for a dispatcher that supports a sequence of types
- class type_sequence_dispatcher_base :
- public type_dispatcher
- {
- private:
- //! Dispatching map element type
- typedef std::pair< typeindex::type_index, void* > dispatching_map_element_type;
- private:
- //! Dispatching map
- const dispatching_map_element_type* m_dispatching_map_begin;
- //! Dispatching map size
- std::size_t m_dispatching_map_size;
- //! Pointer to the receiver function
- void* m_visitor;
- protected:
- //! Initializing constructor
- type_sequence_dispatcher_base(const dispatching_map_element_type* disp_map, std::size_t disp_map_size, void* visitor) BOOST_NOEXCEPT :
- type_dispatcher(&type_sequence_dispatcher_base::get_callback),
- m_dispatching_map_begin(disp_map),
- m_dispatching_map_size(disp_map_size),
- m_visitor(visitor)
- {
- }
- private:
- //! The get_callback method implementation
- static callback_base get_callback(type_dispatcher* p, typeindex::type_index type)
- {
- type_sequence_dispatcher_base* const self = static_cast< type_sequence_dispatcher_base* >(p);
- const dispatching_map_element_type* begin = self->m_dispatching_map_begin;
- const dispatching_map_element_type* end = begin + self->m_dispatching_map_size;
- const dispatching_map_element_type* it = std::lower_bound
- (
- begin,
- end,
- dispatching_map_element_type(type, (void*)0),
- dispatching_map_order()
- );
- if (it != end && it->first == type)
- return callback_base(self->m_visitor, it->second);
- else
- return callback_base();
- }
- // Copying and assignment closed
- BOOST_DELETED_FUNCTION(type_sequence_dispatcher_base(type_sequence_dispatcher_base const&))
- BOOST_DELETED_FUNCTION(type_sequence_dispatcher_base& operator= (type_sequence_dispatcher_base const&))
- };
- //! A dispatcher that supports a sequence of types
- template< typename TypeSequenceT >
- class type_sequence_dispatcher :
- public type_sequence_dispatcher_base
- {
- public:
- //! Type sequence of the supported types
- typedef TypeSequenceT supported_types;
- private:
- //! The dispatching map
- typedef array<
- std::pair< typeindex::type_index, void* >,
- mpl::size< supported_types >::value
- > dispatching_map;
- public:
- /*!
- * Constructor. Initializes the dispatcher internals.
- */
- template< typename VisitorT >
- explicit type_sequence_dispatcher(VisitorT& visitor) :
- type_sequence_dispatcher_base(get_dispatching_map< VisitorT >().data(), dispatching_map::static_size, (void*)boost::addressof(visitor))
- {
- }
- private:
- //! The method returns the dispatching map instance
- template< typename VisitorT >
- static dispatching_map const& get_dispatching_map()
- {
- static const dispatching_map* pinstance = NULL;
- BOOST_LOG_ONCE_BLOCK()
- {
- static dispatching_map instance;
- typename dispatching_map::value_type* p = &*instance.begin();
- typedef typename mpl::begin< supported_types >::type begin_iterator_type;
- typedef typename mpl::end< supported_types >::type end_iterator_type;
- typedef dispatching_map_initializer< VisitorT > initializer;
- initializer::init(static_cast< begin_iterator_type* >(0), static_cast< end_iterator_type* >(0), p);
- std::sort(instance.begin(), instance.end(), dispatching_map_order());
- pinstance = &instance;
- }
- return *pinstance;
- }
- // Copying and assignment closed
- BOOST_DELETED_FUNCTION(type_sequence_dispatcher(type_sequence_dispatcher const&))
- BOOST_DELETED_FUNCTION(type_sequence_dispatcher& operator= (type_sequence_dispatcher const&))
- };
- //! A base class for a single-type dispatcher
- class single_type_dispatcher_base :
- public type_dispatcher
- {
- private:
- //! The type to match against
- typeindex::type_index m_type;
- //! A callback for the supported type
- callback_base m_callback;
- protected:
- //! Initializing constructor
- single_type_dispatcher_base(typeindex::type_index type, callback_base const& cb) BOOST_NOEXCEPT :
- type_dispatcher(&single_type_dispatcher_base::get_callback),
- m_type(type),
- m_callback(cb)
- {
- }
- private:
- //! The get_callback method implementation
- static callback_base get_callback(type_dispatcher* p, typeindex::type_index type)
- {
- single_type_dispatcher_base* const self = static_cast< single_type_dispatcher_base* >(p);
- if (type == self->m_type)
- return self->m_callback;
- else
- return callback_base();
- }
- // Copying and assignment closed
- BOOST_DELETED_FUNCTION(single_type_dispatcher_base(single_type_dispatcher_base const&))
- BOOST_DELETED_FUNCTION(single_type_dispatcher_base& operator= (single_type_dispatcher_base const&))
- };
- //! A simple dispatcher that only supports one type
- template< typename T >
- class single_type_dispatcher :
- public single_type_dispatcher_base
- {
- private:
- typedef void (*trampoline_t)(void*, T const&);
- public:
- //! Constructor
- template< typename VisitorT >
- explicit single_type_dispatcher(VisitorT& visitor) BOOST_NOEXCEPT :
- single_type_dispatcher_base(typeindex::type_id< T >(), callback_base((void*)boost::addressof(visitor), (trampoline_t)&callback_base::trampoline< VisitorT, T >))
- {
- }
- // Copying and assignment closed
- BOOST_DELETED_FUNCTION(single_type_dispatcher(single_type_dispatcher const&))
- BOOST_DELETED_FUNCTION(single_type_dispatcher& operator= (single_type_dispatcher const&))
- };
- } // namespace aux
- /*!
- * \brief A static type dispatcher class
- *
- * The type dispatcher can be used to pass objects of arbitrary types from one
- * component to another. With regard to the library, the type dispatcher
- * can be used to extract attribute values.
- *
- * Static type dispatchers allow to specify one or several supported types at compile
- * time.
- */
- template< typename T >
- class static_type_dispatcher
- #ifndef BOOST_LOG_DOXYGEN_PASS
- :
- public mpl::if_<
- mpl::is_sequence< T >,
- boost::log::aux::type_sequence_dispatcher< T >,
- boost::log::aux::single_type_dispatcher< T >
- >::type
- #endif
- {
- private:
- //! Base type
- typedef typename mpl::if_<
- mpl::is_sequence< T >,
- boost::log::aux::type_sequence_dispatcher< T >,
- boost::log::aux::single_type_dispatcher< T >
- >::type base_type;
- public:
- /*!
- * Constructor. Initializes the dispatcher internals.
- *
- * The \a receiver object is not copied inside the dispatcher, but references to
- * it may be kept by the dispatcher after construction. The receiver object must remain
- * valid until the dispatcher is destroyed.
- *
- * \param receiver Unary function object that will be called on a dispatched value. The receiver
- * must be callable with an argument of any of the supported types of the dispatcher.
- */
- template< typename ReceiverT >
- explicit static_type_dispatcher(ReceiverT& receiver) :
- base_type(receiver)
- {
- }
- // Copying and assignment prohibited
- BOOST_DELETED_FUNCTION(static_type_dispatcher(static_type_dispatcher const&))
- BOOST_DELETED_FUNCTION(static_type_dispatcher& operator= (static_type_dispatcher const&))
- };
- BOOST_LOG_CLOSE_NAMESPACE // namespace log
- } // namespace boost
- #include <boost/log/detail/footer.hpp>
- #endif // BOOST_LOG_STATIC_TYPE_DISPATCHER_HPP_INCLUDED_
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