| // Boost.Signals library |
| |
| // Copyright Douglas Gregor 2001-2004. Use, modification and |
| // distribution is subject to the Boost Software License, Version |
| // 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| // For more information, see http://www.boost.org |
| |
| #ifndef BOOST_SIGNALS_COMMON_HEADER |
| #define BOOST_SIGNALS_COMMON_HEADER |
| |
| #ifndef BOOST_SIGNALS_NAMESPACE |
| # define BOOST_SIGNALS_NAMESPACE signals |
| #endif |
| |
| #include <boost/type_traits/conversion_traits.hpp> |
| #include <boost/ref.hpp> |
| #include <boost/signals/detail/config.hpp> |
| |
| #ifdef BOOST_HAS_ABI_HEADERS |
| # include BOOST_ABI_PREFIX |
| #endif |
| |
| namespace boost { |
| namespace BOOST_SIGNALS_NAMESPACE { |
| namespace detail { |
| // The unusable class is a placeholder for unused function arguments |
| // It is also completely unusable except that it constructable from |
| // anything. This helps compilers without partial specialization |
| // handle slots returning void. |
| struct unusable { |
| unusable() {} |
| }; |
| |
| // Determine the result type of a slot call |
| template<typename R> |
| struct slot_result_type { |
| typedef R type; |
| }; |
| |
| template<> |
| struct slot_result_type<void> { |
| typedef unusable type; |
| }; |
| |
| // Determine if the given type T is a signal |
| class signal_base; |
| |
| template<typename T> |
| struct is_signal { |
| BOOST_STATIC_CONSTANT(bool, |
| value = (is_convertible<T*, signal_base*>::value)); |
| }; |
| |
| /* |
| * The IF implementation is temporary code. When a Boost metaprogramming |
| * library is introduced, Boost.Signals will use it instead. |
| */ |
| namespace intimate { |
| struct SelectThen |
| { |
| template<typename Then, typename Else> |
| struct Result |
| { |
| typedef Then type; |
| }; |
| }; |
| |
| struct SelectElse |
| { |
| template<typename Then, typename Else> |
| struct Result |
| { |
| typedef Else type; |
| }; |
| }; |
| |
| template<bool Condition> |
| struct Selector |
| { |
| typedef SelectThen type; |
| }; |
| |
| template<> |
| struct Selector<false> |
| { |
| typedef SelectElse type; |
| }; |
| } // end namespace intimate |
| |
| template<bool Condition, typename Then, typename Else> |
| struct IF |
| { |
| typedef typename intimate::Selector<Condition>::type select; |
| typedef typename select::template Result<Then,Else>::type type; |
| }; |
| |
| // Determine if the incoming argument is a reference_wrapper |
| #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| template<typename T> |
| struct is_ref |
| { |
| BOOST_STATIC_CONSTANT(bool, value = false); |
| }; |
| |
| template<typename T> |
| struct is_ref<reference_wrapper<T> > |
| { |
| BOOST_STATIC_CONSTANT(bool, value = true); |
| }; |
| #else // no partial specialization |
| typedef char yes_type; |
| typedef double no_type; |
| |
| no_type is_ref_tester(...); |
| |
| template<typename T> |
| yes_type is_ref_tester(reference_wrapper<T>*); |
| |
| template<typename T> |
| struct is_ref |
| { |
| static T* t; |
| BOOST_STATIC_CONSTANT(bool, |
| value = (sizeof(is_ref_tester(t)) == sizeof(yes_type))); |
| }; |
| #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| |
| // A slot can be a signal, a reference to a function object, or a |
| // function object. |
| struct signal_tag {}; |
| struct reference_tag {}; |
| struct value_tag {}; |
| |
| // Classify the given slot as a signal, a reference-to-slot, or a |
| // standard slot |
| template<typename S> |
| class get_slot_tag { |
| typedef typename IF<(is_signal<S>::value), |
| signal_tag, |
| value_tag>::type signal_or_value; |
| |
| public: |
| typedef typename IF<(is_ref<S>::value), |
| reference_tag, |
| signal_or_value>::type type; |
| }; |
| |
| // Forward declaration needed in lots of places |
| class signal_base_impl; |
| class bound_objects_visitor; |
| class slot_base; |
| } // end namespace detail |
| } // end namespace BOOST_SIGNALS_NAMESPACE |
| } // end namespace boost |
| |
| #ifdef BOOST_HAS_ABI_HEADERS |
| # include BOOST_ABI_SUFFIX |
| #endif |
| |
| #endif // BOOST_SIGNALS_COMMON_HEADER |