signals2/detail/tracked_objects_visitor.hpp

0001 // Boost.Signals2 library
0002
0003 // Copyright Frank Mori Hess 2007-2008.
0004 // Copyright Timmo Stange 2007.
0005 // Copyright Douglas Gregor 2001-2004. Use, modification and
0006 // distribution is subject to the Boost Software License, Version
0007 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0008 // http://www.boost.org/LICENSE_1_0.txt)
0009
0010 // For more information, see http://www.boost.org
0011
0012 #ifndef BOOST_SIGNALS2_TRACKED_OBJECTS_VISITOR_HPP
0013 #define BOOST_SIGNALS2_TRACKED_OBJECTS_VISITOR_HPP
0014
0015 #include <boost/core/ref.hpp>
0016 #include <boost/mpl/bool.hpp>
0017 #include <boost/signals2/detail/signals_common.hpp>
0018 #include <boost/signals2/slot_base.hpp>
0019 #include <boost/signals2/trackable.hpp>
0020 #include <boost/type_traits/is_function.hpp>
0021 #include <boost/type_traits/is_pointer.hpp>
0022 #include <boost/type_traits/remove_pointer.hpp>
0023 #include <boost/core/addressof.hpp>
0024
0025 namespace boost
0026 {
0027   namespace signals2
0028   {
0029     namespace detail
0030     {
0031       // Visitor to collect tracked objects from a bound function.
0032       class tracked_objects_visitor
0033       {
0034       public:
0035         tracked_objects_visitor(slot_base *slot) : slot_(slot)
0036         {}
0037         template<typename T>
0038         void operator()(const T& t) const
0039         {
0040             m_visit_reference_wrapper(t, mpl::bool_<is_reference_wrapper<T>::value>());
0041         }
0042       private:
0043         template<typename T>
0044         void m_visit_reference_wrapper(const reference_wrapper<T> &t, const mpl::bool_<true> &) const
0045         {
0046             m_visit_pointer(t.get_pointer(), mpl::bool_<true>());
0047         }
0048         template<typename T>
0049         void m_visit_reference_wrapper(const T &t, const mpl::bool_<false> &) const
0050         {
0051             m_visit_pointer(t, mpl::bool_<is_pointer<T>::value>());
0052         }
0053         template<typename T>
0054         void m_visit_pointer(const T &t, const mpl::bool_<true> &) const
0055         {
0056             m_visit_not_function_pointer(t, mpl::bool_<!is_function<typename remove_pointer<T>::type>::value>());
0057         }
0058         template<typename T>
0059         void m_visit_pointer(const T &t, const mpl::bool_<false> &) const
0060         {
0061             m_visit_pointer(boost::addressof(t), mpl::bool_<true>());
0062         }
0063         template<typename T>
0064         void m_visit_not_function_pointer(const T *t, const mpl::bool_<true> &) const
0065         {
0066             m_visit_signal(t, mpl::bool_<is_signal<T>::value>());
0067         }
0068         template<typename T>
0069         void m_visit_not_function_pointer(const T &, const mpl::bool_<false> &) const
0070         {}
0071         template<typename T>
0072         void m_visit_signal(const T *signal, const mpl::bool_<true> &) const
0073         {
0074           if(signal)
0075             slot_->track_signal(*signal);
0076         }
0077         template<typename T>
0078         void m_visit_signal(const T &t, const mpl::bool_<false> &) const
0079         {
0080             add_if_trackable(t);
0081         }
0082         void add_if_trackable(const trackable *trackable) const
0083         {
0084           if(trackable)
0085             slot_->_tracked_objects.push_back(trackable->get_weak_ptr());
0086         }
0087         void add_if_trackable(const void *) const {}
0088
0089         mutable slot_base * slot_;
0090       };
0091
0092
0093     } // end namespace detail
0094   } // end namespace signals2
0095 } // end namespace boost
0096
0097 #endif // BOOST_SIGNALS2_TRACKED_OBJECTS_VISITOR_HPP
0098