sol2/sol/traits.hpp

// The MIT License (MIT)

// Copyright (c) 2013 Danny Y., Rapptz

// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SOL_TRAITS_HPP
#define SOL_TRAITS_HPP

#include "tuple.hpp"
#include <type_traits>

namespace sol {
template<class T, class...>
struct are_same : std::true_type { };

template<class T, class U, class... Args>
struct are_same<T, U, Args...> : std::integral_constant <bool, std::is_same<T, U>::value && are_same<T, Args...>::value> { };

template<bool B>
using Bool = std::integral_constant<bool, B>;

template<typename T>
using Not = Bool<!T::value>;

template<typename Condition, typename Then, typename Else>
using If = typename std::conditional<Condition::value, Then, Else>::type;

template<typename... Args>
struct And : Bool<true> {};

template<typename T, typename... Args>
struct And<T, Args...> : If<T, And<Args...>, Bool<false>> {};

template<typename... Args>
using EnableIf = typename std::enable_if<And<Args...>::value, int>::type;

template<typename... Args>
using DisableIf = typename std::enable_if<Not<And<Args...>>::value, int>::type;

template<typename T>
using Unqualified = typename std::remove_cv<typename std::remove_reference<T>::type>::type;

template<typename T>
using Decay = typename std::decay<T>::type;

template<typename... Args>
struct return_type {
    typedef std::tuple<Args...> type;
};

template<typename T>
struct return_type<T> {
    typedef T type;
};

template<>
struct return_type<> : types<>{
    typedef void type;
};

template<typename... Args>
struct is_tuple : std::false_type{ };

template<typename... Args>
struct is_tuple<std::tuple<Args...>> : std::true_type{ };

template <typename T, template <typename...> class Templ>
struct is_specialization_of : std::false_type { };
template <typename... T, template <typename...> class Templ>
struct is_specialization_of<Templ<T...>, Templ> : std::true_type { };

namespace detail {
template<typename T, bool isclass = std::is_class<Unqualified<T>>::value>
struct is_function_impl : std::is_function<typename std::remove_pointer<T>::type> {};

template<typename T>
struct is_function_impl<T, true> {
    using yes = char;
    using no = struct { char s[2]; };

    struct F { void operator()(); };
    struct Derived : T, F {};
    template<typename U, U> struct Check;

    template<typename V>
    static no test(Check<void (F::*)(), &V::operator()>*);

    template<typename>
    static yes test(...);

    static const bool value = sizeof(test<Derived>(0)) == sizeof(yes);
};
} // detail

template<typename T>
struct Function : Bool<detail::is_function_impl<T>::value> {};

template<typename TFuncSignature>
struct function_traits;

template<typename T, typename R, typename... Args>
struct function_traits<R(T::*)(Args...)> {
    static const std::size_t arity = sizeof...(Args);
    static const bool is_member_function = true;
    typedef std::tuple<Args...> arg_tuple_type;
    typedef types<Args...> args_type;
    typedef R(T::* function_pointer_type)(Args...);
    typedef typename std::remove_pointer<function_pointer_type>::type function_type;
    typedef R(*free_function_pointer_type)(Args...);
    typedef R return_type;
    template<std::size_t i>
    using arg = typename std::tuple_element<i, arg_tuple_type>::type;
};

template<typename T, typename R, typename... Args>
struct function_traits<R(T::*)(Args...) const> {
    static const std::size_t arity = sizeof...(Args);
    static const bool is_member_function = true;
    typedef std::tuple<Args...> arg_tuple_type;
    typedef types<Args...> args_type;
    typedef R(T::* function_pointer_type)(Args...);
    typedef typename std::remove_pointer<function_pointer_type>::type function_type;
    typedef R(*free_function_pointer_type)(Args...);
    typedef R return_type;
    template<std::size_t i>
    using arg = typename std::tuple_element<i, arg_tuple_type>::type;
};

template<typename R, typename... Args>
struct function_traits<R(Args...)> {
    static const std::size_t arity = sizeof...(Args);
    static const bool is_member_function = false;
    typedef std::tuple<Args...> arg_tuple_type;
    typedef types<Args...> args_type;
    typedef R(function_type)(Args...);
    typedef R(*function_pointer_type)(Args...);
    typedef R(*free_function_pointer_type)(Args...);
    typedef R return_type;
    template<std::size_t i>
    using arg = typename std::tuple_element<i, arg_tuple_type>::type;
};

template<typename R, typename... Args>
struct function_traits<R(*)(Args...)> {
    static const std::size_t arity = sizeof...(Args);
    static const bool is_member_function = false;
    typedef std::tuple<Args...> arg_tuple_type;
    typedef types<Args...> args_type;
    typedef R(function_type)(Args...);
    typedef R(*function_pointer_type)(Args...);
    typedef R(*free_function_pointer_type)(Args...);
    typedef R return_type;
    template<std::size_t i>
    using arg = typename std::tuple_element<i, arg_tuple_type>::type;
};

struct has_begin_end_impl {
    template<typename T, typename U = Unqualified<T>,
                         typename B = decltype(std::declval<U&>().begin()),
                         typename E = decltype(std::declval<U&>().end())>
    static std::true_type test(int);

    template<typename...>
    static std::false_type test(...);
};

template<typename T>
struct has_begin_end : decltype(has_begin_end_impl::test<T>(0)) {};

struct has_key_value_pair_impl {
    template<typename T, typename U = Unqualified<T>,
             typename V = typename U::value_type,
             typename F = decltype(std::declval<V&>().first),
             typename S = decltype(std::declval<V&>().second)>
    static std::true_type test(int);

    template<typename...>
    static std::false_type test(...);
};

template<typename T>
struct has_key_value_pair : decltype(has_key_value_pair_impl::test<T>(0)) {};
} // sol

#endif // SOL_TRAITS_HPP