NoDestroy.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Templates/UnrealTemplate.h"
 
// Special tag for TNoDestroy consteval constructor to avoid confusion with the inner type having
// its own tagged consteval constructor
enum ENoDestroyConstEval { NoDestroyConstEval };
 
template<typename T>
union TNoDestroy
{
    using ElementType = T;
 
    template<typename... ArgTypes>
    [[nodiscard]] explicit consteval TNoDestroy(ENoDestroyConstEval, ArgTypes&&... InArgs)
        : Value(Forward<ArgTypes>(InArgs)...)
    {
    }
 
    template<typename... ArgTypes>
    [[nodiscard]] explicit constexpr TNoDestroy(ArgTypes&&... InArgs)
        : Value(Forward<ArgTypes>(InArgs)...)
    {
    }
 
    UE_NONCOPYABLE(TNoDestroy);
    
    constexpr ~TNoDestroy()
    {
    }
 
    constexpr ElementType* operator&()
    {
        return &Value;
    }
 
    constexpr const ElementType* operator&() const
    {
        return &Value;
    }
 
    constexpr ElementType& operator*()
    {
        return Value;
    }
 
    constexpr const ElementType& operator*() const
    {
        return Value;
    }
 
    ElementType* operator->()
    {
        return &Value;
    }
 
    const ElementType* operator->() const
    {
        return &Value;
    }
private:
    ElementType Value;
};