boost/signals2/slot_base.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_SLOT_BASE_HPP
0013 #define BOOST_SIGNALS2_SLOT_BASE_HPP
0014
0015 #include <boost/shared_ptr.hpp>
0016 #include <boost/weak_ptr.hpp>
0017 #include <boost/signals2/detail/foreign_ptr.hpp>
0018 #include <boost/signals2/expired_slot.hpp>
0019 #include <boost/signals2/signal_base.hpp>
0020 #include <boost/throw_exception.hpp>
0021 #include <boost/variant/apply_visitor.hpp>
0022 #include <boost/variant/variant.hpp>
0023 #include <vector>
0024
0025 namespace boost
0026 {
0027   namespace signals2
0028   {
0029     namespace detail
0030     {
0031       class tracked_objects_visitor;
0032       class trackable_pointee;
0033
0034       typedef boost::variant<boost::weak_ptr<trackable_pointee>, boost::weak_ptr<void>, detail::foreign_void_weak_ptr > void_weak_ptr_variant;
0035       typedef boost::variant<boost::shared_ptr<void>, detail::foreign_void_shared_ptr > void_shared_ptr_variant;
0036       class lock_weak_ptr_visitor
0037       {
0038       public:
0039         typedef void_shared_ptr_variant result_type;
0040         template<typename WeakPtr>
0041         result_type operator()(const WeakPtr &wp) const
0042         {
0043           return wp.lock();
0044         }
0045         // overload to prevent incrementing use count of shared_ptr associated
0046         // with signals2::trackable objects
0047         result_type operator()(const weak_ptr<trackable_pointee> &) const
0048         {
0049           return boost::shared_ptr<void>();
0050         }
0051       };
0052       class expired_weak_ptr_visitor
0053       {
0054       public:
0055         typedef bool result_type;
0056         template<typename WeakPtr>
0057         bool operator()(const WeakPtr &wp) const
0058         {
0059           return wp.expired();
0060         }
0061       };
0062     }
0063
0064     class slot_base
0065     {
0066     public:
0067       typedef std::vector<detail::void_weak_ptr_variant> tracked_container_type;
0068       typedef std::vector<detail::void_shared_ptr_variant> locked_container_type;
0069
0070       const tracked_container_type& tracked_objects() const {return _tracked_objects;}
0071       locked_container_type lock() const
0072       {
0073         locked_container_type locked_objects;
0074         tracked_container_type::const_iterator it;
0075         for(it = tracked_objects().begin(); it != tracked_objects().end(); ++it)
0076         {
0077           locked_objects.push_back(apply_visitor(detail::lock_weak_ptr_visitor(), *it));
0078           if(apply_visitor(detail::expired_weak_ptr_visitor(), *it))
0079           {
0080             boost::throw_exception(expired_slot());
0081           }
0082         }
0083         return locked_objects;
0084       }
0085       bool expired() const
0086       {
0087         tracked_container_type::const_iterator it;
0088         for(it = tracked_objects().begin(); it != tracked_objects().end(); ++it)
0089         {
0090           if(apply_visitor(detail::expired_weak_ptr_visitor(), *it)) return true;
0091         }
0092         return false;
0093       }
0094     protected:
0095       friend class detail::tracked_objects_visitor;
0096
0097       void track_signal(const signal_base &signal)
0098       {
0099         _tracked_objects.push_back(signal.lock_pimpl());
0100       }
0101
0102       tracked_container_type _tracked_objects;
0103     };
0104   }
0105 } // end namespace boost
0106
0107 #endif // BOOST_SIGNALS2_SLOT_BASE_HPP