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