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/*
* Copyright (C) 2018 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <tuple>
#include <type_traits>
namespace WTF {
template<typename T>
struct FunctionTraits;
#if USE(JSVALUE32_64)
template<typename T>
static constexpr unsigned slotsForCCallArgument()
{
static_assert(!std::is_class<T>::value || sizeof(T) <= sizeof(void*), "This doesn't support complex structs.");
static_assert(sizeof(T) == 8 || sizeof(T) <= 4);
// This assumes that all integral values are passed on the stack.
if (sizeof(T) == 8)
return 2;
return 1;
}
template<typename T>
static constexpr unsigned computeCCallSlots() { return slotsForCCallArgument<T>(); }
template<typename T, typename... Ts>
static constexpr std::enable_if_t<!!sizeof...(Ts), unsigned> computeCCallSlots() { return computeCCallSlots<Ts...>() + slotsForCCallArgument<T>(); }
#endif
template<typename Result, typename... Args>
struct FunctionTraits<Result(Args...)> {
using ResultType = Result;
static constexpr bool hasResult = !std::is_same<ResultType, void>::value;
static constexpr std::size_t arity = sizeof...(Args);
template <std::size_t n, typename = std::enable_if_t<(n < arity)>>
using ArgumentType = typename std::tuple_element<n, std::tuple<Args...>>::type;
using ArgumentTypes = std::tuple<Args...>;
#if USE(JSVALUE64)
static constexpr unsigned cCallArity() { return arity; }
#else
static constexpr unsigned cCallArity() { return computeCCallSlots<Args...>(); }
#endif // USE(JSVALUE64)
};
#if OS(WINDOWS)
template<typename Result, typename... Args>
struct FunctionTraits<Result SYSV_ABI(Args...)> : public FunctionTraits<Result(Args...)> {
};
#endif
template<typename Result, typename... Args>
struct FunctionTraits<Result(*)(Args...)> : public FunctionTraits<Result(Args...)> {
};
#if OS(WINDOWS)
template<typename Result, typename... Args>
struct FunctionTraits<Result SYSV_ABI (*)(Args...)> : public FunctionTraits<Result(Args...)> {
};
#endif
template<typename Result, typename... Args>
struct FunctionTraits<Result(Args...) noexcept> : public FunctionTraits<Result(Args...)> {
};
template<typename Result, typename... Args>
struct FunctionTraits<Result(*)(Args...) noexcept> : public FunctionTraits<Result(Args...)> {
};
} // namespace WTF
using WTF::FunctionTraits;
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