ceph/src/boost/boost/type_traits/is_copy_constructible.hpp

   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_noncopyable.hpp>
  41
  42 namespace boost {
  43
  44    namespace detail
  45    {
  46
  47       template <class T, bool b> struct is_copy_constructible_imp : public boost::is_constructible<T, const T&>{};
  48       template <class T> struct is_copy_constructible_imp<T, true> : public false_type{};
  49
  50    }
  51
  52    template <class T> struct is_copy_constructible : public detail::is_copy_constructible_imp<T, is_noncopyable<T>::value>{};
  53
  54    template <> struct is_copy_constructible<void> : public false_type{};
  55    template <> struct is_copy_constructible<void const> : public false_type{};
  56    template <> struct is_copy_constructible<void const volatile> : public false_type{};
  57    template <> struct is_copy_constructible<void volatile> : public false_type{};
  58
  59 } // namespace boost
  60
  61 #endif
  62
  63 #else
  64
  65 #include <boost/type_traits/detail/yes_no_type.hpp>
  66 #include <boost/type_traits/is_noncopyable.hpp>
  67 #include <boost/type_traits/add_reference.hpp>
  68 #include <boost/type_traits/is_rvalue_reference.hpp>
  69 #include <boost/type_traits/declval.hpp>
  70 #include <boost/type_traits/is_array.hpp>
  71 #include <boost/type_traits/declval.hpp>
  72
  73 #ifdef BOOST_MSVC
  74 #pragma warning(push)
  75 #pragma warning(disable:4181)
  76 #endif
  77
  78 namespace boost {
  79
  80    namespace detail{
  81
  82       template <bool DerivedFromNoncopyable, class T>
  83       struct is_copy_constructible_impl2 {
  84
  85          // Intel compiler has problems with SFINAE for copy constructors and deleted functions:
  86          //
  87          // error: function *function_name* cannot be referenced -- it is a deleted function
  88          // static boost::type_traits::yes_type test(T1&, decltype(T1(boost::declval<T1&>()))* = 0);
  89          //                                                        ^
  90          //
  91          // MSVC 12.0 (Visual 2013) has problems when the copy constructor has been deleted. See:
  92          // https://connect.microsoft.com/VisualStudio/feedback/details/800328/std-is-copy-constructible-is-broken
  93 #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) && !defined(BOOST_INTEL_CXX_VERSION) && !(defined(BOOST_MSVC) && _MSC_VER == 1800)
  94
  95 #ifdef BOOST_NO_CXX11_DECLTYPE
  96          template <class T1>
  97          static boost::type_traits::yes_type test(const T1&, boost::mpl::int_<sizeof(T1(boost::declval<const T1&>()))>* = 0);
  98 #else
  99          template <class T1>
 100          static boost::type_traits::yes_type test(const T1&, decltype(T1(boost::declval<const T1&>()))* = 0);
 101 #endif
 102
 103          static boost::type_traits::no_type test(...);
 104 #else
 105          template <class T1>
 106          static boost::type_traits::no_type test(const T1&, typename T1::boost_move_no_copy_constructor_or_assign* = 0);
 107          static boost::type_traits::yes_type test(...);
 108 #endif
 109
 110          // If you see errors like this:
 111          //
 112          //      `'T::T(const T&)' is private`
 113          //      `boost/type_traits/is_copy_constructible.hpp:68:5: error: within this context`
 114          //
 115          // then you are trying to call that macro for a structure defined like that:
 116          //
 117          //      struct T {
 118          //          ...
 119          //      private:
 120          //          T(const T &);
 121          //          ...
 122          //      };
 123          //
 124          // To fix that you must modify your structure:
 125          //
 126          //      // C++03 and C++11 version
 127          //      struct T: private boost::noncopyable {
 128          //          ...
 129          //      private:
 130          //          T(const T &);
 131          //          ...
 132          //      };
 133          //
 134          //      // C++11 version
 135          //      struct T {
 136          //          ...
 137          //      private:
 138          //          T(const T &) = delete;
 139          //          ...
 140          //      };
 141          BOOST_STATIC_CONSTANT(bool, value = (
 142             sizeof(test(
 143             boost::declval<BOOST_DEDUCED_TYPENAME boost::add_reference<T const>::type>()
 144             )) == sizeof(boost::type_traits::yes_type)
 145             &&
 146             !boost::is_rvalue_reference<T>::value
 147             && !boost::is_array<T>::value
 148             ));
 149       };
 150
 151       template <class T>
 152       struct is_copy_constructible_impl2<true, T> {
 153          BOOST_STATIC_CONSTANT(bool, value = false);
 154       };
 155
 156       template <class T>
 157       struct is_copy_constructible_impl {
 158
 159          BOOST_STATIC_CONSTANT(bool, value = (
 160             boost::detail::is_copy_constructible_impl2<
 161             boost::is_noncopyable<T>::value,
 162             T
 163             >::value
 164             ));
 165       };
 166
 167    } // namespace detail
 168
 169    template <class T> struct is_copy_constructible : public integral_constant<bool, ::boost::detail::is_copy_constructible_impl<T>::value>{};
 170    template <> struct is_copy_constructible<void> : public false_type{};
 171 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
 172    template <> struct is_copy_constructible<void const> : public false_type{};
 173    template <> struct is_copy_constructible<void volatile> : public false_type{};
 174    template <> struct is_copy_constructible<void const volatile> : public false_type{};
 175 #endif
 176
 177 } // namespace boost
 178
 179 #ifdef BOOST_MSVC
 180 #pragma warning(pop)
 181 #endif
 182
 183 #endif
 184
 185 #endif // BOOST_TT_IS_COPY_CONSTRUCTIBLE_HPP_INCLUDED