source: NonGTP/Boost/boost/signals/detail/slot_call_iterator.hpp @ 857

Revision 857, 3.0 KB checked in by igarcia, 19 years ago (diff)
Line 
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
24namespace 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:
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
58        dereference() const
59        {
60          if (!cache->is_initialized()) {
61            cache->reset(f(*iter));
62          }
63
64          return cache->get();
65        }
66
67        void increment()
68        {
69          iter = std::find_if(++iter, end, is_callable());
70          cache->reset();
71        }
72
73        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
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