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1 | // Boost.Signals library |
2 | ||
3 | // Copyright Douglas Gregor 2001-2004. | |
4 | // Copyright Frank Mori Hess 2007. Use, modification and | |
5 | // distribution is subject to 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 | // For more information, see http://www.boost.org | |
10 | ||
11 | #ifndef BOOST_SIGNALS2_SIGNALS_COMMON_HPP | |
12 | #define BOOST_SIGNALS2_SIGNALS_COMMON_HPP | |
13 | ||
14 | #include <boost/mpl/bool.hpp> | |
15 | #include <boost/mpl/if.hpp> | |
16 | #include <boost/ref.hpp> | |
17 | #include <boost/signals2/signal_base.hpp> | |
18 | #include <boost/type_traits/is_base_of.hpp> | |
19 | ||
20 | namespace boost { | |
21 | namespace signals2 { | |
22 | namespace detail { | |
23 | // Determine if the given type T is a signal | |
24 | template<typename T> | |
25 | class is_signal: public mpl::bool_<is_base_of<signal_base, T>::value> | |
26 | {}; | |
27 | ||
28 | // A slot can be a signal, a reference to a function object, or a | |
29 | // function object. | |
30 | struct signal_tag {}; | |
31 | struct reference_tag {}; | |
32 | struct value_tag {}; | |
33 | ||
34 | // Classify the given slot as a signal, a reference-to-slot, or a | |
35 | // standard slot | |
36 | template<typename S> | |
37 | class get_slot_tag { | |
38 | typedef typename mpl::if_<is_signal<S>, | |
39 | signal_tag, value_tag>::type signal_or_value; | |
40 | public: | |
41 | typedef typename mpl::if_<is_reference_wrapper<S>, | |
42 | reference_tag, | |
43 | signal_or_value>::type type; | |
44 | }; | |
45 | ||
46 | // Get the slot so that it can be copied | |
47 | template<typename F> | |
48 | typename F::weak_signal_type | |
49 | get_invocable_slot(const F &signal, signal_tag) | |
50 | { return typename F::weak_signal_type(signal); } | |
51 | ||
52 | template<typename F> | |
53 | const F& | |
54 | get_invocable_slot(const F& f, reference_tag) | |
55 | { return f; } | |
56 | ||
57 | template<typename F> | |
58 | const F& | |
59 | get_invocable_slot(const F& f, value_tag) | |
60 | { return f; } | |
61 | ||
62 | // Determines the type of the slot - is it a signal, a reference to a | |
63 | // slot or just a normal slot. | |
64 | template<typename F> | |
65 | typename get_slot_tag<F>::type | |
66 | tag_type(const F&) | |
67 | { | |
68 | typedef typename get_slot_tag<F>::type | |
69 | the_tag_type; | |
70 | the_tag_type tag = the_tag_type(); | |
71 | return tag; | |
72 | } | |
73 | } // end namespace detail | |
74 | } // end namespace signals2 | |
75 | } // end namespace boost | |
76 | ||
77 | #endif // BOOST_SIGNALS2_SIGNALS_COMMON_HPP |