1 | // (C) Copyright Antony Polukhin 2013. |
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_CONSTRUCTIBLE_HPP_INCLUDED |
10 | #define BOOST_TT_IS_COPY_CONSTRUCTIBLE_HPP_INCLUDED |
11 | |
12 | #include <boost/config.hpp> |
13 | #include <boost/detail/workaround.hpp> |
14 | |
15 | #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, < 1800) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40900) |
16 | |
17 | #include <boost/type_traits/is_constructible.hpp> |
18 | |
19 | #if !BOOST_WORKAROUND(BOOST_MSVC, <= 1800) |
20 | |
21 | namespace boost { |
22 | |
23 | template <class T> struct is_copy_constructible : public boost::is_constructible<T, const T&>{}; |
24 | |
25 | template <> struct is_copy_constructible<void> : public false_type{}; |
26 | template <> struct is_copy_constructible<void const> : public false_type{}; |
27 | template <> struct is_copy_constructible<void const volatile> : public false_type{}; |
28 | template <> struct is_copy_constructible<void volatile> : public false_type{}; |
29 | |
30 | } // namespace boost |
31 | |
32 | #else |
33 | // |
34 | // Special version for VC12 which has a problem when a base class (such as non_copyable) has a deleted |
35 | // copy constructor. In this case the compiler thinks there really is a copy-constructor and tries to |
36 | // instantiate the deleted member. std::is_copy_constructible has the same issue (or at least returns |
37 | // an incorrect value, which just defers the issue into the users code) as well. We can at least fix |
38 | // boost::non_copyable as a base class as a special case: |
39 | // |
40 | #include <boost/type_traits/is_base_and_derived.hpp> |
41 | #include <boost/noncopyable.hpp> |
42 | |
43 | namespace boost { |
44 | |
45 | namespace detail |
46 | { |
47 | |
48 | template <class T, bool b> struct is_copy_constructible_imp : public boost::is_constructible<T, const T&>{}; |
49 | template <class T> struct is_copy_constructible_imp<T, true> : public false_type{}; |
50 | |
51 | } |
52 | |
53 | template <class T> struct is_copy_constructible : public detail::is_copy_constructible_imp<T, is_base_and_derived<boost::noncopyable, T>::value>{}; |
54 | |
55 | template <> struct is_copy_constructible<void> : public false_type{}; |
56 | template <> struct is_copy_constructible<void const> : public false_type{}; |
57 | template <> struct is_copy_constructible<void const volatile> : public false_type{}; |
58 | template <> struct is_copy_constructible<void volatile> : public false_type{}; |
59 | |
60 | } // namespace boost |
61 | |
62 | #endif |
63 | |
64 | #else |
65 | |
66 | #include <boost/type_traits/detail/yes_no_type.hpp> |
67 | #include <boost/type_traits/is_base_and_derived.hpp> |
68 | #include <boost/type_traits/add_reference.hpp> |
69 | #include <boost/type_traits/is_rvalue_reference.hpp> |
70 | #include <boost/type_traits/declval.hpp> |
71 | #include <boost/type_traits/is_array.hpp> |
72 | #include <boost/type_traits/declval.hpp> |
73 | #include <boost/noncopyable.hpp> |
74 | |
75 | #ifdef BOOST_MSVC |
76 | #pragma warning(push) |
77 | #pragma warning(disable:4181) |
78 | #endif |
79 | |
80 | namespace boost { |
81 | |
82 | namespace detail{ |
83 | |
84 | template <bool DerivedFromNoncopyable, class T> |
85 | struct is_copy_constructible_impl2 { |
86 | |
87 | // Intel compiler has problems with SFINAE for copy constructors and deleted functions: |
88 | // |
89 | // error: function *function_name* cannot be referenced -- it is a deleted function |
90 | // static boost::type_traits::yes_type test(T1&, decltype(T1(boost::declval<T1&>()))* = 0); |
91 | // ^ |
92 | // |
93 | // MSVC 12.0 (Visual 2013) has problems when the copy constructor has been deleted. See: |
94 | // https://connect.microsoft.com/VisualStudio/feedback/details/800328/std-is-copy-constructible-is-broken |
95 | #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_INTEL_CXX_VERSION) && !(defined(BOOST_MSVC) && _MSC_VER == 1800) |
96 | |
97 | #ifdef BOOST_NO_CXX11_DECLTYPE |
98 | template <class T1> |
99 | static boost::type_traits::yes_type test(const T1&, boost::mpl::int_<sizeof(T1(boost::declval<const T1&>()))>* = 0); |
100 | #else |
101 | template <class T1> |
102 | static boost::type_traits::yes_type test(const T1&, decltype(T1(boost::declval<const T1&>()))* = 0); |
103 | #endif |
104 | |
105 | static boost::type_traits::no_type test(...); |
106 | #else |
107 | template <class T1> |
108 | static boost::type_traits::no_type test(const T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0); |
109 | static boost::type_traits::yes_type test(...); |
110 | #endif |
111 | |
112 | // If you see errors like this: |
113 | // |
114 | // `'T::T(const T&)' is private` |
115 | // `boost/type_traits/is_copy_constructible.hpp:68:5: error: within this context` |
116 | // |
117 | // then you are trying to call that macro for a structure defined like that: |
118 | // |
119 | // struct T { |
120 | // ... |
121 | // private: |
122 | // T(const T &); |
123 | // ... |
124 | // }; |
125 | // |
126 | // To fix that you must modify your structure: |
127 | // |
128 | // // C++03 and C++11 version |
129 | // struct T: private boost::noncopyable { |
130 | // ... |
131 | // private: |
132 | // T(const T &); |
133 | // ... |
134 | // }; |
135 | // |
136 | // // C++11 version |
137 | // struct T { |
138 | // ... |
139 | // private: |
140 | // T(const T &) = delete; |
141 | // ... |
142 | // }; |
143 | BOOST_STATIC_CONSTANT(bool, value = ( |
144 | sizeof(test( |
145 | boost::declval<BOOST_DEDUCED_TYPENAME boost::add_reference<T const>::type>() |
146 | )) == sizeof(boost::type_traits::yes_type) |
147 | && |
148 | !boost::is_rvalue_reference<T>::value |
149 | && !boost::is_array<T>::value |
150 | )); |
151 | }; |
152 | |
153 | template <class T> |
154 | struct is_copy_constructible_impl2<true, T> { |
155 | BOOST_STATIC_CONSTANT(bool, value = false); |
156 | }; |
157 | |
158 | template <class T> |
159 | struct is_copy_constructible_impl { |
160 | |
161 | BOOST_STATIC_CONSTANT(bool, value = ( |
162 | boost::detail::is_copy_constructible_impl2< |
163 | boost::is_base_and_derived<boost::noncopyable, T>::value, |
164 | T |
165 | >::value |
166 | )); |
167 | }; |
168 | |
169 | } // namespace detail |
170 | |
171 | template <class T> struct is_copy_constructible : public integral_constant<bool, ::boost::detail::is_copy_constructible_impl<T>::value>{}; |
172 | template <> struct is_copy_constructible<void> : public false_type{}; |
173 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS |
174 | template <> struct is_copy_constructible<void const> : public false_type{}; |
175 | template <> struct is_copy_constructible<void volatile> : public false_type{}; |
176 | template <> struct is_copy_constructible<void const volatile> : public false_type{}; |
177 | #endif |
178 | |
179 | } // namespace boost |
180 | |
181 | #ifdef BOOST_MSVC |
182 | #pragma warning(pop) |
183 | #endif |
184 | |
185 | #endif |
186 | |
187 | #endif // BOOST_TT_IS_COPY_CONSTRUCTIBLE_HPP_INCLUDED |
188 | |