VVMEmergentType.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#if WITH_VERSE_VM || defined(__INTELLISENSE__)
 
#include "VerseVM/VVMBitMap.h"
#include "VerseVM/VVMCell.h"
#include "VerseVM/VVMEmergentTypeCreator.h"
#include "VerseVM/VVMGlobalHeapPtr.h"
#include <new>
 
namespace Verse
{
struct VShape;
struct VType;
struct VMap;
 
struct VEmergentType final : VCell
{
    DECLARE_DERIVED_VCPPCLASSINFO(COREUOBJECT_API, VCell);
 
    TWriteBarrier<VShape> Shape; // This is immutable. If you need to change an object's shape, transition to a new emergent type that points to your new shape instead.
    TWriteBarrier<VType> Type;
    TWriteBarrier<VEmergentType> MeltTransition;
    VCppClassInfo* CppClassInfo = nullptr;
 
    // We use this to track what fields have been created for objects
    VBitMap CreatedFields;
 
    // A cache of types made when calling `MarkFieldAsCreated`
    TWriteBarrier<VMap> CachedFieldTransitions;
 
    static VEmergentType* New(FAllocationContext Context, VType* Type, VCppClassInfo* CppClassInfo)
    {
        return new (Context.AllocateEmergentType(sizeof(VEmergentType))) VEmergentType(Context, VEmergentTypeCreator::EmergentTypeForEmergentType.Get(), Type, CppClassInfo);
    }
 
    static VEmergentType* New(FAllocationContext Context, VShape* InShape, VType* Type, VCppClassInfo* CppClassInfo)
    {
        return new (Context.AllocateEmergentType(sizeof(VEmergentType))) VEmergentType(Context, InShape, VEmergentTypeCreator::EmergentTypeForEmergentType.Get(), Type, CppClassInfo);
    }
 
    static VEmergentType* New(FAllocationContext Context, const VEmergentType* Other, const VBitMap* InCreatedFields)
    {
        return new (Context.AllocateEmergentType(sizeof(VEmergentType))) VEmergentType(Context, Other, InCreatedFields);
    }
 
    VEmergentType& GetOrCreateMeltTransition(FAllocationContext Context)
    {
        if (VEmergentType* Transition = MeltTransition.Get())
        {
            return *Transition;
        }
        return GetOrCreateMeltTransitionSlow(Context);
    }
 
    static bool Equals(const VEmergentType& EmergentType, VType* Type, VCppClassInfo* CppClassInfo)
    {
        return EmergentType.Shape.Get() == nullptr && EmergentType.Type.Get() == Type && EmergentType.CppClassInfo == CppClassInfo;
    }
 
    static bool Equals(const VEmergentType& EmergentType, const VShape* InShape, VType* Type, VCppClassInfo* CppClassInfo)
    {
        return EmergentType.Shape.Get() == InShape && EmergentType.Type.Get() == Type && EmergentType.CppClassInfo == CppClassInfo;
    }
 
    static bool Equals(FAllocationContext Context, const VEmergentType& EmergentType, const VEmergentType* Other, const VBitMap* InCreatedFields);
 
    friend uint32 GetTypeHash(const VEmergentType& EmergentType)
    {
        uint32 Hash = HashCombineFast(::GetTypeHash(EmergentType.Shape.Get()), ::GetTypeHash(EmergentType.Type.Get()));
        Hash = HashCombineFast(Hash, ::GetTypeHash(EmergentType.CppClassInfo));
        Hash = HashCombineFast(Hash, GetTypeHash(EmergentType.CreatedFields));
        return Hash;
    }
 
    COREUOBJECT_API bool IsFieldCreated(uint32 FieldIndex);
    COREUOBJECT_API VEmergentType* MarkFieldAsCreated(FAllocationContext Context, uint32 FieldIndex);
 
    // Emergent types are not serialized; this also prevents them from being recorded.
    static constexpr bool SerializeIdentity = false;
 
private:
    friend class VEmergentTypeCreator;
 
    // Need this for the EmergentType of EmergentType.
    static VEmergentType* NewIncomplete(FAllocationContext Context, VCppClassInfo* CppClassInfo)
    {
        return new (Context.AllocateEmergentType(sizeof(VEmergentType))) VEmergentType(Context, CppClassInfo);
    }
 
    VEmergentType& GetOrCreateMeltTransitionSlow(FAllocationContext);
 
    void SetEmergentType(FAccessContext Context, VEmergentType* EmergentType)
    {
        VCell::SetEmergentType(Context, EmergentType);
    }
 
    VEmergentType(FAllocationContext Context, VCppClassInfo* CppClassInfo)
        : VCell()
        , CppClassInfo(CppClassInfo)
    {
    }
 
    VEmergentType(FAllocationContext Context, VEmergentType* EmergentType, VType* T, VCppClassInfo* CppClassInfo)
        : VCell(Context, EmergentType)
        , Type(Context, T)
        , CppClassInfo(CppClassInfo)
    {
    }
 
    VEmergentType(FAllocationContext Context, VShape* InShape, VEmergentType* EmergentType, VType* InType, VCppClassInfo* InCppClassInfo);
 
    VEmergentType(FAllocationContext Context, const VEmergentType* Other, const VBitMap* InCreatedFields);
};
 
}; // namespace Verse
 
#endif // WITH_VERSE_VM