ceph/src/boost/boost/signals2/optional_last_value.hpp

   1 // optional_last_value function object (documented as part of Boost.Signals2)
   2
   3 // Copyright Frank Mori Hess 2007-2008.
   4 // Copyright Douglas Gregor 2001-2003.
   5 // Distributed under the Boost Software License, Version
   6 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8
   9 // See http://www.boost.org/libs/signals2 for library home page.
  10
  11 #ifndef BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
  12 #define BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
  13
  14 #include <boost/core/no_exceptions_support.hpp>
  15 #include <boost/optional.hpp>
  16 #include <boost/signals2/expired_slot.hpp>
  17
  18 namespace boost {
  19   namespace signals2 {
  20
  21     template<typename T>
  22       class optional_last_value
  23     {
  24     public:
  25       typedef optional<T> result_type;
  26
  27       template<typename InputIterator>
  28         optional<T> operator()(InputIterator first, InputIterator last) const
  29       {
  30         optional<T> value;
  31         while (first != last)
  32         {
  33           BOOST_TRY
  34           {
  35             value = *first;
  36           }
  37           BOOST_CATCH(const expired_slot &) {}
  38           BOOST_CATCH_END
  39           ++first;
  40         }
  41         return value;
  42       }
  43     };
  44
  45     template<>
  46       class optional_last_value<void>
  47     {
  48     public:
  49       typedef void result_type;
  50       template<typename InputIterator>
  51         result_type operator()(InputIterator first, InputIterator last) const
  52       {
  53         while (first != last)
  54         {
  55           BOOST_TRY
  56           {
  57             *first;
  58           }
  59           BOOST_CATCH(const expired_slot &) {}
  60           BOOST_CATCH_END
  61           ++first;
  62         }
  63         return;
  64       }
  65     };
  66   } // namespace signals2
  67 } // namespace boost
  68 #endif // BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP