ladybird/AK/Function.h
Andreas Kling 5d180d1f99 Everywhere: Rename ASSERT => VERIFY
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)

Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.

We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
2021-02-23 20:56:54 +01:00

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C++

/*
* 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>
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
{
VERIFY(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;