0533f6d1a6
`as_if<T>()` previously had a fast path that used `fast_is<T>()` and a static cast. Mixin types couldn't use this fast path, since a static cast from a sibling base is not valid, so would fall back to using a slow dynamic cast instead. This change adds a `fast_as<T>()` mechanism for mixin types to opt in to and teaches `as_if<T>()` to use it. This means `as<T>()` and `as_if<T>()` can be used with mixin types without incurring the overhead of a dynamic cast
94 lines
2.6 KiB
C++
94 lines
2.6 KiB
C++
/*
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* Copyright (c) 2020-2021, Andreas Kling <andreas@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Assertions.h>
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#include <AK/Concepts.h>
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#include <AK/Forward.h>
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#include <AK/Platform.h>
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namespace AK {
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE bool is(InputType& input)
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{
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static_assert(!SameAs<RemoveCVReference<OutputType>, RemoveCVReference<InputType>>);
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if constexpr (requires { input.template fast_is<RemoveCVReference<OutputType>>(); }) {
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return input.template fast_is<RemoveCVReference<OutputType>>();
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}
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return dynamic_cast<CopyConst<InputType, OutputType>*>(&input);
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE bool is(InputType* input)
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{
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return input && is<OutputType>(*input);
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE bool is(NonnullRefPtr<InputType> const& input)
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{
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return is<OutputType>(*input);
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE CopyConst<InputType, OutputType>* as_if(InputType& input)
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{
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if constexpr (requires { input.template fast_as<RemoveCVReference<OutputType>>(); }) {
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return input.template fast_as<RemoveCVReference<OutputType>>();
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} else if constexpr (requires { input.template fast_is<RemoveCVReference<OutputType>>(); static_cast<CopyConst<InputType, OutputType>*>(&input); }) {
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if (!is<OutputType>(input))
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return nullptr;
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return static_cast<CopyConst<InputType, OutputType>*>(&input);
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}
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return dynamic_cast<CopyConst<InputType, OutputType>*>(&input);
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE CopyConst<InputType, OutputType>* as_if(InputType* input)
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{
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if (!input)
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return nullptr;
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return as_if<OutputType>(*input);
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE CopyConst<InputType, OutputType>& as(InputType& input)
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{
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auto* result = as_if<OutputType>(input);
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VERIFY(result);
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return *result;
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE CopyConst<InputType, OutputType>* as(InputType* input)
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{
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if (!input)
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return nullptr;
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auto* result = as_if<OutputType>(input);
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VERIFY(result);
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return result;
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}
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template<typename OutputType, typename InputType>
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ALWAYS_INLINE CopyConst<InputType, OutputType>* bridge_cast(InputType input)
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{
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#ifdef AK_HAS_OBJC_ARC
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return (__bridge CopyConst<InputType, OutputType>*)(input);
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#else
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return static_cast<CopyConst<InputType, OutputType>*>(input);
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#endif
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}
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}
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#if USING_AK_GLOBALLY
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using AK::as;
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using AK::as_if;
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using AK::bridge_cast;
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using AK::is;
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#endif
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