1 | // (C) Copyright Ion Gaztanaga 2014. |
2 | // |
3 | // Use, modification and distribution are subject to the Boost Software License, |
4 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
5 | // http://www.boost.org/LICENSE_1_0.txt). |
6 | // |
7 | // See http://www.boost.org/libs/type_traits for most recent version including documentation. |
8 | |
9 | #ifndef BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |
10 | #define BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |
11 | |
12 | #include <boost/config.hpp> |
13 | #include <boost/type_traits/detail/yes_no_type.hpp> |
14 | #include <boost/type_traits/is_base_and_derived.hpp> |
15 | #include <boost/noncopyable.hpp> |
16 | |
17 | #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_NO_CXX11_DECLTYPE) \ |
18 | && !defined(BOOST_INTEL_CXX_VERSION) && \ |
19 | !(defined(BOOST_MSVC) && _MSC_VER == 1800) |
20 | #define BOOST_TT_CXX11_IS_COPY_ASSIGNABLE |
21 | #include <boost/type_traits/declval.hpp> |
22 | #else |
23 | //For compilers without decltype |
24 | #include <boost/type_traits/is_const.hpp> |
25 | #include <boost/type_traits/is_array.hpp> |
26 | #include <boost/type_traits/add_reference.hpp> |
27 | #include <boost/type_traits/remove_reference.hpp> |
28 | #endif |
29 | |
30 | namespace boost { |
31 | |
32 | namespace detail{ |
33 | |
34 | template <bool DerivedFromNoncopyable, class T> |
35 | struct is_copy_assignable_impl2 { |
36 | |
37 | // Intel compiler has problems with SFINAE for copy constructors and deleted functions: |
38 | // |
39 | // error: function *function_name* cannot be referenced -- it is a deleted function |
40 | // static boost::type_traits::yes_type test(T1&, decltype(T1(boost::declval<T1&>()))* = 0); |
41 | // ^ |
42 | // |
43 | // MSVC 12.0 (Visual 2013) has problems when the copy constructor has been deleted. See: |
44 | // https://connect.microsoft.com/VisualStudio/feedback/details/800328/std-is-copy-constructible-is-broken |
45 | #if defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE) |
46 | typedef boost::type_traits::yes_type yes_type; |
47 | typedef boost::type_traits::no_type no_type; |
48 | |
49 | template <class U> |
50 | static decltype(::boost::declval<U&>() = ::boost::declval<const U&>(), yes_type() ) test(int); |
51 | |
52 | template <class> |
53 | static no_type test(...); |
54 | |
55 | static const bool value = sizeof(test<T>(0)) == sizeof(yes_type); |
56 | |
57 | #else |
58 | static BOOST_DEDUCED_TYPENAME boost::add_reference<T>::type produce(); |
59 | |
60 | template <class T1> |
61 | static boost::type_traits::no_type test(T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0); |
62 | |
63 | static boost::type_traits::yes_type test(...); |
64 | // If you see errors like this: |
65 | // |
66 | // `'T::operator=(const T&)' is private` |
67 | // `boost/type_traits/is_copy_assignable.hpp:NN:M: error: within this context` |
68 | // |
69 | // then you are trying to call that macro for a structure defined like that: |
70 | // |
71 | // struct T { |
72 | // ... |
73 | // private: |
74 | // T & operator=(const T &); |
75 | // ... |
76 | // }; |
77 | // |
78 | // To fix that you must modify your structure: |
79 | // |
80 | // // C++03 and C++11 version |
81 | // struct T: private boost::noncopyable { |
82 | // ... |
83 | // private: |
84 | // T & operator=(const T &); |
85 | // ... |
86 | // }; |
87 | // |
88 | // // C++11 version |
89 | // struct T { |
90 | // ... |
91 | // private: |
92 | // T& operator=(const T &) = delete; |
93 | // ... |
94 | // }; |
95 | BOOST_STATIC_CONSTANT(bool, value = ( |
96 | sizeof(test(produce())) == sizeof(boost::type_traits::yes_type) |
97 | )); |
98 | #endif |
99 | }; |
100 | |
101 | template <class T> |
102 | struct is_copy_assignable_impl2<true, T> { |
103 | BOOST_STATIC_CONSTANT(bool, value = false); |
104 | }; |
105 | |
106 | template <class T> |
107 | struct is_copy_assignable_impl { |
108 | |
109 | #if !defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE) |
110 | //For compilers without decltype, at least return false on const types, arrays |
111 | //types derived from boost::noncopyable and types defined as BOOST_MOVEABLE_BUT_NOT_COPYABLE |
112 | typedef BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type unreferenced_t; |
113 | BOOST_STATIC_CONSTANT(bool, value = ( |
114 | boost::detail::is_copy_assignable_impl2< |
115 | boost::is_base_and_derived<boost::noncopyable, T>::value |
116 | || boost::is_const<unreferenced_t>::value || boost::is_array<unreferenced_t>::value |
117 | ,T |
118 | >::value |
119 | )); |
120 | #else |
121 | BOOST_STATIC_CONSTANT(bool, value = ( |
122 | boost::detail::is_copy_assignable_impl2< |
123 | boost::is_base_and_derived<boost::noncopyable, T>::value,T |
124 | >::value |
125 | )); |
126 | #endif |
127 | }; |
128 | |
129 | } // namespace detail |
130 | |
131 | template <class T> struct is_copy_assignable : public integral_constant<bool, ::boost::detail::is_copy_assignable_impl<T>::value>{}; |
132 | template <> struct is_copy_assignable<void> : public false_type{}; |
133 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS |
134 | template <> struct is_copy_assignable<void const> : public false_type{}; |
135 | template <> struct is_copy_assignable<void const volatile> : public false_type{}; |
136 | template <> struct is_copy_assignable<void volatile> : public false_type{}; |
137 | #endif |
138 | |
139 | } // namespace boost |
140 | |
141 | #endif // BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |
142 | |