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/*
* Copyright (C) 2016 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 <AK/Assertions.h>
#include <AK/OwnPtr.h>
#include <AK/StdLibExtras.h>
#include <AK/Traits.h>
namespace AK {
template<typename>
class Function;
template<typename Out, typename... In>
class Function<Out(In...)> {
public:
Function() = default;
template<typename CallableType, class = typename EnableIf<!(IsPointer<CallableType>::value && IsFunction<typename RemovePointer<CallableType>::Type>::value) && IsRvalueReference<CallableType&&>::value>::Type>
Function(CallableType&& callable)
: m_callable_wrapper(make<CallableWrapper<CallableType>>(move(callable)))
{
}
template<typename FunctionType, class = typename EnableIf<IsPointer<FunctionType>::value && IsFunction<typename RemovePointer<FunctionType>::Type>::value>::Type>
Function(FunctionType f)
: m_callable_wrapper(make<CallableWrapper<FunctionType>>(move(f)))
{
}
Out operator()(In... in) const
{
ASSERT(m_callable_wrapper);
return m_callable_wrapper->call(forward<In>(in)...);
}
explicit operator bool() const { return !!m_callable_wrapper; }
template<typename CallableType, class = typename EnableIf<!(IsPointer<CallableType>::value && IsFunction<typename RemovePointer<CallableType>::Type>::value) && IsRvalueReference<CallableType&&>::value>::Type>
Function& operator=(CallableType&& callable)
{
m_callable_wrapper = make<CallableWrapper<CallableType>>(move(callable));
return *this;
}
template<typename FunctionType, class = typename EnableIf<IsPointer<FunctionType>::value && IsFunction<typename RemovePointer<FunctionType>::Type>::value>::Type>
Function& operator=(FunctionType f)
{
m_callable_wrapper = make<CallableWrapper<FunctionType>>(move(f));
return *this;
}
Function& operator=(std::nullptr_t)
{
m_callable_wrapper = nullptr;
return *this;
}
private:
class CallableWrapperBase {
public:
virtual ~CallableWrapperBase() = default;
virtual Out call(In...) const = 0;
};
template<typename CallableType>
class CallableWrapper final : public CallableWrapperBase {
public:
explicit CallableWrapper(CallableType&& callable)
: m_callable(move(callable))
{
}
CallableWrapper(const CallableWrapper&) = delete;
CallableWrapper& operator=(const CallableWrapper&) = delete;
Out call(In... in) const final override
{
if constexpr (requires { m_callable(forward<In>(in)...); }) {
return m_callable(forward<In>(in)...);
} else if constexpr (requires { m_callable(); }) {
return m_callable();
} else if constexpr (IsSame<void, Out>::value) {
return;
} else {
return {};
}
}
private:
CallableType m_callable;
};
OwnPtr<CallableWrapperBase> m_callable_wrapper;
};
}
using AK::Function;
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