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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 |