| // (C) Copyright Ion Gaztanaga 2014. |
| // |
| // Use, modification and distribution are 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). |
| // |
| // See http://www.boost.org/libs/type_traits for most recent version including documentation. |
| |
| #ifndef BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |
| #define BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |
| |
| #include <boost/config.hpp> |
| #include <boost/type_traits/detail/yes_no_type.hpp> |
| #include <boost/type_traits/is_base_and_derived.hpp> |
| #include <boost/noncopyable.hpp> |
| |
| #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_NO_CXX11_DECLTYPE) \ |
| && !defined(BOOST_INTEL_CXX_VERSION) && \ |
| !(defined(BOOST_MSVC) && _MSC_VER == 1800) |
| #define BOOST_TT_CXX11_IS_COPY_ASSIGNABLE |
| #include <boost/type_traits/declval.hpp> |
| #else |
| //For compilers without decltype |
| #include <boost/type_traits/is_const.hpp> |
| #include <boost/type_traits/is_array.hpp> |
| #include <boost/type_traits/add_reference.hpp> |
| #include <boost/type_traits/remove_reference.hpp> |
| #endif |
| |
| namespace boost { |
| |
| namespace detail{ |
| |
| template <bool DerivedFromNoncopyable, class T> |
| struct is_copy_assignable_impl2 { |
| |
| // Intel compiler has problems with SFINAE for copy constructors and deleted functions: |
| // |
| // error: function *function_name* cannot be referenced -- it is a deleted function |
| // static boost::type_traits::yes_type test(T1&, decltype(T1(boost::declval<T1&>()))* = 0); |
| // ^ |
| // |
| // MSVC 12.0 (Visual 2013) has problems when the copy constructor has been deleted. See: |
| // https://connect.microsoft.com/VisualStudio/feedback/details/800328/std-is-copy-constructible-is-broken |
| #if defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE) |
| typedef boost::type_traits::yes_type yes_type; |
| typedef boost::type_traits::no_type no_type; |
| |
| template <class U> |
| static decltype(::boost::declval<U&>() = ::boost::declval<const U&>(), yes_type() ) test(int); |
| |
| template <class> |
| static no_type test(...); |
| |
| static const bool value = sizeof(test<T>(0)) == sizeof(yes_type); |
| |
| #else |
| static BOOST_DEDUCED_TYPENAME boost::add_reference<T>::type produce(); |
| |
| template <class T1> |
| static boost::type_traits::no_type test(T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0); |
| |
| static boost::type_traits::yes_type test(...); |
| // If you see errors like this: |
| // |
| // `'T::operator=(const T&)' is private` |
| // `boost/type_traits/is_copy_assignable.hpp:NN:M: error: within this context` |
| // |
| // then you are trying to call that macro for a structure defined like that: |
| // |
| // struct T { |
| // ... |
| // private: |
| // T & operator=(const T &); |
| // ... |
| // }; |
| // |
| // To fix that you must modify your structure: |
| // |
| // // C++03 and C++11 version |
| // struct T: private boost::noncopyable { |
| // ... |
| // private: |
| // T & operator=(const T &); |
| // ... |
| // }; |
| // |
| // // C++11 version |
| // struct T { |
| // ... |
| // private: |
| // T& operator=(const T &) = delete; |
| // ... |
| // }; |
| BOOST_STATIC_CONSTANT(bool, value = ( |
| sizeof(test(produce())) == sizeof(boost::type_traits::yes_type) |
| )); |
| #endif |
| }; |
| |
| template <class T> |
| struct is_copy_assignable_impl2<true, T> { |
| BOOST_STATIC_CONSTANT(bool, value = false); |
| }; |
| |
| template <class T> |
| struct is_copy_assignable_impl { |
| |
| #if !defined(BOOST_TT_CXX11_IS_COPY_ASSIGNABLE) |
| //For compilers without decltype, at least return false on const types, arrays |
| //types derived from boost::noncopyable and types defined as BOOST_MOVEABLE_BUT_NOT_COPYABLE |
| typedef BOOST_DEDUCED_TYPENAME boost::remove_reference<T>::type unreferenced_t; |
| BOOST_STATIC_CONSTANT(bool, value = ( |
| boost::detail::is_copy_assignable_impl2< |
| boost::is_base_and_derived<boost::noncopyable, T>::value |
| || boost::is_const<unreferenced_t>::value || boost::is_array<unreferenced_t>::value |
| ,T |
| >::value |
| )); |
| #else |
| BOOST_STATIC_CONSTANT(bool, value = ( |
| boost::detail::is_copy_assignable_impl2< |
| boost::is_base_and_derived<boost::noncopyable, T>::value,T |
| >::value |
| )); |
| #endif |
| }; |
| |
| } // namespace detail |
| |
| template <class T> struct is_copy_assignable : public integral_constant<bool, ::boost::detail::is_copy_assignable_impl<T>::value>{}; |
| template <> struct is_copy_assignable<void> : public false_type{}; |
| #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS |
| template <> struct is_copy_assignable<void const> : public false_type{}; |
| template <> struct is_copy_assignable<void const volatile> : public false_type{}; |
| template <> struct is_copy_assignable<void volatile> : public false_type{}; |
| #endif |
| |
| } // namespace boost |
| |
| #endif // BOOST_TT_IS_COPY_ASSIGNABLE_HPP_INCLUDED |