EM_Task/CoreUObject/Private/Serialization/TraceReferences.cpp

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

#include "Serialization/TraceReferences.h"
#include "UObject/UnrealType.h"

PRAGMA_DISABLE_DEPRECATION_WARNINGS

// This traces referenced/referencer of an object using FArchiveObjectGraph
FTraceReferences::FTraceReferences(bool bIncludeTransients, EObjectFlags KeepFlags)
    : ArchiveObjectGraph(bIncludeTransients, KeepFlags)
{}

FString FTraceReferences::GetReferencerString(UObject* Object, int32 Depth)
{
    TArray<FObjectGraphNode*> Referencers;
    FString OutString;

    if (GetReferencer(Object, Referencers, false, Depth) > 0)
    {
        int32 CurrentDepth = 0, NumPrinted = 0;

        do
        {
            NumPrinted = 0;
            for (int32 RefId = 0; RefId < Referencers.Num(); ++RefId)
            {
                FObjectGraphNode* Node = Referencers[RefId];
                if (CurrentDepth == Node->ReferenceDepth)
                {
                    ++NumPrinted;
                    OutString += FString::Printf(TEXT("(%d) %s%s"), CurrentDepth, *Node->NodeObject->GetPathName(), LINE_TERMINATOR);

                    for (int32 Id = 0; Id < Node->ReferencerProperties.Num(); ++Id)
                    {
                        OutString += FString::Printf(TEXT("\t(%d) %s%s"), Id + 1, *Node->ReferencerProperties[Id]->GetName(), LINE_TERMINATOR);
                    }
                }
            }

            ++CurrentDepth;
        } while (NumPrinted > 0 || CurrentDepth == 0);
    }

    return OutString;
}

FString FTraceReferences::GetReferencedString(UObject* Object, int32 Depth)
{
    TArray<FObjectGraphNode*> Referenced;
    FString OutString;

    if (GetReferenced(Object, Referenced, false, Depth) > 0)
    {
        int32 CurrentDepth = 0, NumPrinted = 0;

        do
        {
            NumPrinted = 0;
            for (int32 RefId = 0; RefId < Referenced.Num(); ++RefId)
            {
                FObjectGraphNode* Node = Referenced[RefId];
                if (CurrentDepth == Node->ReferenceDepth)
                {
                    ++NumPrinted;
                    OutString += FString::Printf(TEXT("(%d) %s%s"), CurrentDepth, *Node->NodeObject->GetPathName(), LINE_TERMINATOR);

                    for (int32 Id = 0; Id < Node->ReferencerProperties.Num(); ++Id)
                    {
                        OutString += FString::Printf(TEXT("\t(%d) %s%s"), Id + 1, *Node->ReferencerProperties[Id]->GetName(), LINE_TERMINATOR);
                    }
                }
            }

            ++CurrentDepth;
        } while (NumPrinted > 0 || CurrentDepth == 0);
    }

    return OutString;
}

int32 FTraceReferences::GetReferencer(UObject* Object, TArray<FObjectGraphNode*>& Referencer, bool bExcludeSelf, int32 Depth)
{
    ArchiveObjectGraph.ClearSearchFlags();
    Referencer.Empty();

    GetReferencerInternal(Object, Referencer, 0, Depth);

    if (bExcludeSelf)
    {
        // remove head
        Referencer.RemoveAt(0);
    }

    return Referencer.Num();
}

void FTraceReferences::GetReferencerInternal(UObject* CurrentObject, TArray<FObjectGraphNode*>& OutReferencer, int32 CurrentDepth, int32 TargetDepth)
{
    if (TargetDepth >= CurrentDepth)
    {
        FObjectGraphNode* CurrentTarget = ArchiveObjectGraph.ObjectGraph.FindRef(CurrentObject);

        if (CurrentTarget && !CurrentTarget->Visited && CurrentTarget->ReferencerRecords.Num() > 0)
        {
            // set Depth and add to outerReferencer
            CurrentTarget->Visited        = true;
            CurrentTarget->ReferenceDepth = CurrentDepth;
            OutReferencer.Add(CurrentTarget);

            // go through all referncers and call referencerinternal
            for (TMap<UObject*, FTraceRouteRecord>::TIterator Iter(CurrentTarget->ReferencerRecords); Iter; ++Iter)
            {
                bool HasValidProperty         = false;
                FTraceRouteRecord& Referencer = Iter.Value();

                for (int32 Idx = 0; Idx < Referencer.ReferencerProperties.Num(); ++Idx)
                {
                    if (Referencer.ReferencerProperties[Idx])
                    {
                        CurrentTarget->ReferencerProperties.Add(Referencer.ReferencerProperties[Idx]);
                        HasValidProperty = true;
                    }
                }

                if (HasValidProperty)
                {
                    GetReferencerInternal(Referencer.GraphNode->NodeObject, OutReferencer, CurrentDepth + 1, TargetDepth);
                }
            }
        }
    }
}

int32 FTraceReferences::GetReferenced(UObject* Object, TArray<FObjectGraphNode*>& Referenced, bool bExcludeSelf, int32 Depth)
{
    ArchiveObjectGraph.ClearSearchFlags();
    Referenced.Empty();

    GetReferencedInternal(Object, Referenced, 0, Depth);

    if (bExcludeSelf)
    {
        // remove head
        Referenced.RemoveAt(0);
    }

    return Referenced.Num();
}

void FTraceReferences::GetReferencedInternal(UObject* CurrentObject, TArray<FObjectGraphNode*>& OutReferenced, int32 CurrentDepth, int32 TargetDepth)
{
    if (TargetDepth >= CurrentDepth)
    {
        FObjectGraphNode* CurrentTarget = ArchiveObjectGraph.ObjectGraph.FindRef(CurrentObject);

        if (CurrentTarget && !CurrentTarget->Visited && CurrentTarget->ReferencedObjects.Num() > 0)
        {
            // set Depth and add to outerReferencer
            CurrentTarget->Visited        = true;
            CurrentTarget->ReferenceDepth = CurrentDepth;
            OutReferenced.Add(CurrentTarget);

            // go through all refernced and call referencedinternal
            for (TMap<UObject*, FTraceRouteRecord>::TIterator Iter(CurrentTarget->ReferencedObjects); Iter; ++Iter)
            {
                bool HasValidProperty         = false;
                FTraceRouteRecord& Referenced = Iter.Value();

                for (int32 Idx = 0; Idx < Referenced.ReferencerProperties.Num(); ++Idx)
                {
                    if (Referenced.ReferencerProperties[Idx])
                    {
                        // For referenced, it makes sense if we add property to the referenced, instead of target
                        Referenced.GraphNode->ReferencerProperties.Add(Referenced.ReferencerProperties[Idx]);
                        HasValidProperty = true;
                        break;
                    }
                }

                if (HasValidProperty)
                {
                    // it has property set up, call getreferenced again
                    GetReferencedInternal(Referenced.GraphNode->NodeObject, OutReferenced, CurrentDepth + 1, TargetDepth);
                }
            }
        }
    }
}

PRAGMA_ENABLE_DEPRECATION_WARNINGS