DataLayerInstanceNames.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "CoreMinimal.h"
 
#include "DataLayerInstanceNames.generated.h"
 
USTRUCT()
struct FDataLayerInstanceNames
{
    GENERATED_USTRUCT_BODY()
 
    FDataLayerInstanceNames()
    : bIsFirstDataLayerExternal(false)
    {
#if WITH_EDITOR
        bIsForcedEmptyNonExternalDataLayers = false;
#endif
    }
 
    FDataLayerInstanceNames(const TArray<FName>& InDataLayers, bool bInIsFirstDataLayerExternal)
    {
        const int32 NonExternalDataLayersOffset = bInIsFirstDataLayerExternal && InDataLayers.Num() ? 1 : 0;
        const int32 NumNonExternalDataLayers = InDataLayers.Num() - NonExternalDataLayersOffset;
        const FName ExternalDataLayer = (NonExternalDataLayersOffset > 0) ? InDataLayers[0] : NAME_None;
        Initialize(MakeArrayView(NumNonExternalDataLayers ? &InDataLayers[NonExternalDataLayersOffset] : nullptr, NumNonExternalDataLayers), ExternalDataLayer);
    }
 
    FDataLayerInstanceNames(const TArray<FName>& InNonExternalDataLayers, FName InExternalDataLayer)
    {
        Initialize(InNonExternalDataLayers, InExternalDataLayer);
    }
 
    const FName GetExternalDataLayer() const
    {
        check(!bIsFirstDataLayerExternal || !DataLayers.IsEmpty());
        return bIsFirstDataLayerExternal ? DataLayers[0] : NAME_None;
    }
 
    TArray<FName>::RangedForIteratorType             begin() { return DataLayers.begin(); }
    TArray<FName>::RangedForConstIteratorType        begin() const { return DataLayers.begin(); }
    TArray<FName>::RangedForIteratorType             end() { return DataLayers.end(); }
    TArray<FName>::RangedForConstIteratorType        end() const { return DataLayers.end(); }
    TArray<FName>::RangedForReverseIteratorType      rbegin() { return DataLayers.rbegin(); }
    TArray<FName>::RangedForConstReverseIteratorType rbegin() const { return DataLayers.rbegin(); }
    TArray<FName>::RangedForReverseIteratorType      rend() { return DataLayers.rend(); }
    TArray<FName>::RangedForConstReverseIteratorType rend() const { return DataLayers.rend(); }
 
    TArrayView<const FName> GetNonExternalDataLayers() const
    {
        static TArray<FName> EmptyArray;
        check(!bIsFirstDataLayerExternal || !DataLayers.IsEmpty());
        const int32 Offset = bIsFirstDataLayerExternal ? 1 : 0;
        const int32 NonExternalDataLayersCount = DataLayers.Num() - Offset;
        return NonExternalDataLayersCount > 0 ? MakeArrayView(&DataLayers[Offset], NonExternalDataLayersCount) : EmptyArray;
    }
 
    int32 Num() const { return DataLayers.Num(); }
    bool IsEmpty() const { return DataLayers.IsEmpty(); }
    bool Contains(FName InDataLayer) const { return DataLayers.Contains(InDataLayer); }
    bool HasExternalDataLayer() const { return bIsFirstDataLayerExternal; }
    const TArray<FName>& ToArray() const { return DataLayers; }
 
private:
 
    void Initialize(TArrayView<const FName> InNonExternalDataLayers, FName InExternalDataLayer)
    {
#if WITH_EDITOR
        bIsForcedEmptyNonExternalDataLayers = false;
#endif
        bIsFirstDataLayerExternal = !InExternalDataLayer.IsNone();
 
        DataLayers.Reserve(InNonExternalDataLayers.Num() + (bIsFirstDataLayerExternal ? 1 : 0));
        if (bIsFirstDataLayerExternal)
        {
            DataLayers.Add(InExternalDataLayer);
        }
        for (FName DataLayer : InNonExternalDataLayers)
        {
            if (DataLayer != InExternalDataLayer)
            {
                DataLayers.AddUnique(DataLayer);
            }
        }
    }
 
#if WITH_EDITOR
    bool IsForcedEmptyNonExternalDataLayers() const { return bIsForcedEmptyNonExternalDataLayers; }
    void ForceEmptyNonExternalDataLayers()
    {
        bIsForcedEmptyNonExternalDataLayers = true;
        if (bIsFirstDataLayerExternal)
        {
            DataLayers = { DataLayers[0] };
        }
        else
        {
            DataLayers.Empty();
        }
    }
    bool bIsForcedEmptyNonExternalDataLayers;
#endif
 
    UPROPERTY()
    bool bIsFirstDataLayerExternal;
 
    UPROPERTY()
    TArray<FName> DataLayers;
 
    friend class FStreamingGenerationActorDescView;
};