EM_Task/AssetRegistry/Public/AssetRegistry/AssetRegistryHelpers.h

// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "AssetRegistryModule.h"
#include "AssetRegistry/AssetData.h"
#include "AssetRegistry/ARFilter.h"
#include "AssetRegistry/IAssetRegistry.h"
#include "AssetRegistryHelpers.generated.h"

USTRUCT(BlueprintType)
struct FTagAndValue
{
    GENERATED_BODY()

    UPROPERTY(BlueprintReadWrite, Transient, Category = AssetData)
    FName Tag;

    UPROPERTY(BlueprintReadWrite, Transient, Category = AssetData)
    FString Value;
};

UCLASS(transient)
class UAssetRegistryHelpers: public UObject
{
    GENERATED_BODY()

public:
    UFUNCTION(BlueprintPure, Category = "Asset Registry")
    static TScriptInterface<IAssetRegistry> GetAssetRegistry();

    /**
     * Creates asset data from a UObject.
     *
     * @param InAsset	The asset to create asset data for
     * @param bAllowBlueprintClass	By default trying to create asset data for a blueprint class will create one for the UBlueprint instead
     */
    UFUNCTION(BlueprintPure, Category = "Asset Data")
    static FAssetData CreateAssetData(const UObject* InAsset, bool bAllowBlueprintClass = false);

    /** Checks to see if this AssetData refers to an asset or is NULL */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static bool IsValid(const FAssetData& InAssetData);

    /** Returns true if this is the primary asset in a package, true for maps and assets but false for secondary objects like class redirectors */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static bool IsUAsset(const FAssetData& InAssetData);

    /** Returns true if the this asset is a redirector. */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static bool IsRedirector(const FAssetData& InAssetData);

    /** Returns the full name for the asset in the form: Class ObjectPath */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static FString GetFullName(const FAssetData& InAssetData);

    /** Convert to a SoftObjectPath for loading */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static FSoftObjectPath ToSoftObjectPath(const FAssetData& InAssetData);

    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static UClass* GetClass(const FAssetData& InAssetData);

    /** Returns the asset UObject if it is loaded or loads the asset if it is unloaded then returns the result */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static UObject* GetAsset(const FAssetData& InAssetData);

    /** Returns true if the asset is loaded */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static bool IsAssetLoaded(const FAssetData& InAssetData);

    /** Returns the name for the asset in the form: Class'ObjectPath' */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static FString GetExportTextName(const FAssetData& InAssetData);

    /** Gets the value associated with the given tag as a string */
    UFUNCTION(BlueprintPure, Category = "Asset Data", meta = (ScriptMethod))
    static bool GetTagValue(const FAssetData& InAssetData, const FName& InTagName, FString& OutTagValue);

    /**
     * Populates the FARFilters tags and values map with the passed in tags and values
     */
    UFUNCTION(BlueprintPure, Category = "Asset Registry")
    static FARFilter SetFilterTagsAndValues(const FARFilter& InFilter, const TArray<FTagAndValue>& InTagsAndValues);

    /** Enable/disable asset registry caching mode for the duration of the scope */
    struct ASSETREGISTRY_API FTemporaryCachingModeScope
    {
        FTemporaryCachingModeScope(bool InTempCachingMode);
        ~FTemporaryCachingModeScope();

    private:
        bool PreviousCachingMode;
    };
};

inline void GetReferencersData(UObject* Object, UClass* MatchClass, TArray<FAssetData>& OutAssetDatas)
{
    FAssetRegistryModule& AssetRegistryModule = FModuleManager::LoadModuleChecked<
        FAssetRegistryModule>("AssetRegistry");
    IAssetRegistry& AssetRegistry = AssetRegistryModule.Get();

    TArray<FAssetIdentifier> Referencers;
    AssetRegistry.GetReferencers(Object->GetOuter()->GetFName(), Referencers);

    for (auto AssetIdentifier: Referencers)
    {
        TArray<FAssetData> Assets;
        AssetRegistry.GetAssetsByPackageName(AssetIdentifier.PackageName, Assets);

        for (auto AssetData: Assets)
        {
            if (MatchClass != nullptr)
            {
                if (AssetData.GetClass()->IsChildOf(MatchClass))
                {
                    OutAssetDatas.AddUnique(AssetData);
                }
            }
            else
            {
                OutAssetDatas.AddUnique(AssetData);
            }
        }
    }
}

template <class T>
void GetReferencersOfType(UObject* Object, TArray<T*>& OutObjects)
{
    TArray<FAssetData> AssetDatas;
    GetReferencersData(Object, T::StaticClass(), AssetDatas);

    for (auto Data: AssetDatas)
    {
        T* TypedAsset = Cast<T>(Data.GetAsset());
        if (TypedAsset != nullptr)
        {
            OutObjects.Add(TypedAsset);
        }
    }
}