Tidy traits

This commit is contained in:
Simon Brand
2019-06-25 10:52:35 +01:00
parent 3878a899ab
commit 7b60e7a6b2

View File

@ -237,10 +237,41 @@ template <class B, class... Bs>
struct conjunction<B, Bs...>
: std::conditional<bool(B::value), conjunction<Bs...>, B>::type {};
#if defined(_LIBCPP_VERSION) && __cplusplus == 201103L
#define TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
#endif
// In C++11 mode, there's an issue in libc++'s std::mem_fn
// which results in a hard-error when using it in a noexcept expression
// in some cases. This is a check to workaround the common failing case.
#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
template <class T> struct is_pointer_to_non_const_member_func : std::false_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...)> : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...)&> : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) &&> : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) volatile> : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) volatile &> : std::true_type {};
template <class T, class Ret, class... Args>
struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) volatile &&> : std::true_type {};
template <class T> struct is_const_or_const_ref : std::false_type {};
template <class T> struct is_const_or_const_ref<T const&> : std::true_type {};
template <class T> struct is_const_or_const_ref<T const> : std::true_type {};
#endif
// std::invoke from C++17
// https://stackoverflow.com/questions/38288042/c11-14-invoke-workaround
template <typename Fn, typename... Args,
typename = enable_if_t<std::is_member_pointer<decay_t<Fn>>{}>,
#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
typename = enable_if_t<!(is_pointer_to_non_const_member_func<Fn>::value
&& is_const_or_const_ref<Args...>::value)>,
#endif
typename = enable_if_t<std::is_member_pointer<decay_t<Fn>>::value>,
int = 0>
constexpr auto invoke(Fn && f, Args && ... args) noexcept(
noexcept(std::mem_fn(f)(std::forward<Args>(args)...)))
@ -249,7 +280,7 @@ constexpr auto invoke(Fn &&f, Args &&... args) noexcept(
}
template <typename Fn, typename... Args,
typename = enable_if_t<!std::is_member_pointer<decay_t<Fn>>{}>>
typename = enable_if_t<!std::is_member_pointer<decay_t<Fn>>::value>>
constexpr auto invoke(Fn && f, Args && ... args) noexcept(
noexcept(std::forward<Fn>(f)(std::forward<Args>(args)...)))
-> decltype(std::forward<Fn>(f)(std::forward<Args>(args)...)) {
@ -2421,5 +2452,4 @@ void swap(expected<T, E> &lhs,
}
} // namespace tl
#define TL_OPTIONAL_EXPECTED_MUTEX
#endif