1 // Boost.Signals library 2 3 // Copyright Douglas Gregor 2001-2004. Use, modification and 4 // distribution is subject to the Boost Software License, Version 5 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at 6 // http://www.boost.org/LICENSE_1_0.txt) 7 8 // For more information, see http://www.boost.org 9 10 #ifndef BOOST_SIGNALS_SLOT_CALL_ITERATOR 11 #define BOOST_SIGNALS_SLOT_CALL_ITERATOR 12 13 #include <memory> 14 #include <boost/iterator/iterator_facade.hpp> 15 #include <boost/smart_ptr.hpp> 16 #include <boost/signals/detail/config.hpp> 17 #include <boost/signals/connection.hpp> 18 #include <boost/optional.hpp> 19 20 #ifdef BOOST_HAS_ABI_HEADERS 21 # include BOOST_ABI_PREFIX 22 #endif 23 24 namespace boost { 25 namespace BOOST_SIGNALS_NAMESPACE { 26 namespace detail { 27 28 // Generates a slot call iterator. Essentially, this is an iterator that: 29 // - skips over disconnected slots in the underlying list 30 // - calls the connected slots when dereferenced 31 // - caches the result of calling the slots 32 template<typename Function, typename Iterator> 33 class slot_call_iterator 34 : public iterator_facade<slot_call_iterator<Function, Iterator>, 35 typename Function::result_type, 36 single_pass_traversal_tag, 37 typename Function::result_type const&> 38 { 39 typedef iterator_facade<slot_call_iterator<Function, Iterator>, 40 typename Function::result_type, 41 single_pass_traversal_tag, 42 typename Function::result_type const&> 43 inherited; 44 45 typedef typename Function::result_type result_type; 46 47 friend class iterator_core_access; 48 49 public: slot_call_iterator(Iterator iter_in,Iterator end_in,Function f,optional<result_type> & c)50 slot_call_iterator(Iterator iter_in, Iterator end_in, Function f, 51 optional<result_type> &c) 52 : iter(iter_in), end(end_in), f(f), cache(&c) 53 { 54 iter = std::find_if(iter, end, is_callable()); 55 } 56 57 typename inherited::reference dereference() const58 dereference() const 59 { 60 if (!cache->is_initialized()) { 61 cache->reset(f(*iter)); 62 } 63 64 return cache->get(); 65 } 66 increment()67 void increment() 68 { 69 iter = std::find_if(++iter, end, is_callable()); 70 cache->reset(); 71 } 72 equal(const slot_call_iterator & other) const73 bool equal(const slot_call_iterator& other) const 74 { 75 iter = std::find_if(iter, end, is_callable()); 76 other.iter = std::find_if(other.iter, other.end, 77 is_callable()); 78 return iter == other.iter; 79 } 80 81 private: 82 mutable Iterator iter; 83 Iterator end; 84 Function f; 85 optional<result_type>* cache; 86 }; 87 } // end namespace detail 88 } // end namespace BOOST_SIGNALS_NAMESPACE 89 } // end namespace boost 90 91 #ifdef BOOST_HAS_ABI_HEADERS 92 # include BOOST_ABI_SUFFIX 93 #endif 94 95 #endif // BOOST_SIGNALS_SLOT_CALL_ITERATOR 96