74 lines
1.8 KiB
C
74 lines
1.8 KiB
C
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#pragma once
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#include "CoreTypes.h"
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#include "Templates/Utility.h"
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#include "TypeTraits/TypeTraits.h"
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NAMESPACE_REDCRAFT_BEGIN
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NAMESPACE_MODULE_BEGIN(Redcraft)
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NAMESPACE_MODULE_BEGIN(Utility)
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/**
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* A helper class which replaces T& as a function parameter when the reference is
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* intended to be retained by the function (e.g. as a class member). The benefit
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* of this class is that it is a compile error to pass an rvalue which might otherwise
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* bind to a const reference, which is dangerous when the reference is retained.
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*
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* struct FRAIIType
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* {
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* explicit FRAIIType(TRetainedRef<const FThing> InThing) : Ref(InThing) { }
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*
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* void DoSomething() { Ref.Something(); }
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*
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* FThing& Ref;
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* };
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*
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*/
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template <typename T>
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struct TRetainedRef
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{
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/** Retain a non-const lvalue reference. */
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FORCEINLINE constexpr TRetainedRef(T& InRef) : Ref(InRef) { }
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/** Can't retain a rvalue reference. */
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TRetainedRef(const T& ) = delete;
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TRetainedRef( T&&) = delete;
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TRetainedRef(const T&&) = delete;
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/** @return The managed reference. */
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FORCEINLINE constexpr operator T&() const { return Ref; }
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FORCEINLINE constexpr T& Get() const { return Ref; }
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private:
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T& Ref;
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};
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template <typename T>
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struct TRetainedRef<const T>
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{
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/** Retain a non-const lvalue reference. */
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FORCEINLINE constexpr TRetainedRef(T& InRef) : Ref(InRef) { }
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/** Retain a const lvalue reference. */
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FORCEINLINE constexpr TRetainedRef(const T& InRef) : Ref(InRef) { }
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/** Can't retain a rvalue reference. */
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TRetainedRef( T&&) = delete;
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TRetainedRef(const T&&) = delete;
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/** @return The managed reference. */
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FORCEINLINE constexpr operator const T&() const { return Ref; }
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FORCEINLINE constexpr const T& Get() const { return Ref; }
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private:
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const T& Ref;
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};
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NAMESPACE_MODULE_END(Utility)
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NAMESPACE_MODULE_END(Redcraft)
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NAMESPACE_REDCRAFT_END
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