void FPendingDelete::CheckForReferences()
{
if ( bReferencesChecked )
{
return;
}
bReferencesChecked = true;
// Load the asset registry module
FAssetRegistryModule& AssetRegistryModule = FModuleManager::LoadModuleChecked<FAssetRegistryModule>( TEXT( "AssetRegistry" ) );
AssetRegistryModule.Get().GetReferencers(Object->GetOutermost()->GetFName(), DiskReferences);
// Check and see whether we are referenced by any objects that won't be garbage collected (*including* the undo buffer)
FReferencerInformationList ReferencesIncludingUndo;
bool bReferencedInMemoryOrUndoStack = IsReferenced(Object, GARBAGE_COLLECTION_KEEPFLAGS, true, &ReferencesIncludingUndo);
// Determine the in-memory references, *excluding* the undo buffer
GEditor->Trans->DisableObjectSerialization();
bIsReferencedInMemoryByNonUndo = IsReferenced(Object, GARBAGE_COLLECTION_KEEPFLAGS, true, &MemoryReferences);
GEditor->Trans->EnableObjectSerialization();
// see if this object is the transaction buffer - set a flag so we know we need to clear the undo stack
const int32 TotalReferenceCount = ReferencesIncludingUndo.ExternalReferences.Num() + ReferencesIncludingUndo.InternalReferences.Num();
const int32 NonUndoReferenceCount = MemoryReferences.ExternalReferences.Num() + MemoryReferences.InternalReferences.Num();
bIsReferencedInMemoryByUndo = TotalReferenceCount > NonUndoReferenceCount;
}
void FPendingDelete::CheckForReferences()
{
if ( bReferencesChecked )
{
return;
}
bReferencesChecked = true;
// Load the asset registry module
FAssetRegistryModule& AssetRegistryModule = FModuleManager::LoadModuleChecked<FAssetRegistryModule>( TEXT( "AssetRegistry" ) );
AssetRegistryModule.Get().GetReferencers(Object->GetOutermost()->GetFName(), DiskReferences);
// Check and see whether we are referenced by any objects that won't be garbage collected (*including* the undo buffer)
FReferencerInformationList ReferencesIncludingUndo;
bool bReferencedInMemoryOrUndoStack = IsReferenced(Object, GARBAGE_COLLECTION_KEEPFLAGS, true, &ReferencesIncludingUndo);
// Determine the in-memory references, *excluding* the undo buffer
GEditor->Trans->DisableObjectSerialization();
bIsReferencedInMemoryByNonUndo = IsReferenced(Object, GARBAGE_COLLECTION_KEEPFLAGS, true, &MemoryReferences);
GEditor->Trans->EnableObjectSerialization();
// see if this object is the transaction buffer - set a flag so we know we need to clear the undo stack
const int32 TotalReferenceCount = ReferencesIncludingUndo.ExternalReferences.Num() + ReferencesIncludingUndo.InternalReferences.Num();
const int32 NonUndoReferenceCount = MemoryReferences.ExternalReferences.Num() + MemoryReferences.InternalReferences.Num();
bIsReferencedInMemoryByUndo = TotalReferenceCount > NonUndoReferenceCount;
// If the object itself isn't in the transaction buffer, check to see if it's a Blueprint asset. We might have instances of the
// Blueprint in the transaction buffer, in which case we also want to both alert the user and clear it prior to deleting the asset.
if ( !bIsReferencedInMemoryByUndo )
{
UBlueprint* Blueprint = Cast<UBlueprint>( Object );
if ( Blueprint && Blueprint->GeneratedClass )
{
TArray<FReferencerInformation> ExternalMemoryReferences = MemoryReferences.ExternalReferences;
for ( auto RefIt = ExternalMemoryReferences.CreateIterator(); RefIt && !bIsReferencedInMemoryByUndo; ++RefIt )
{
FReferencerInformation& RefInfo = *RefIt;
if ( RefInfo.Referencer->IsA( Blueprint->GeneratedClass ) )
{
if ( IsReferenced( RefInfo.Referencer, GARBAGE_COLLECTION_KEEPFLAGS, true, &ReferencesIncludingUndo ) )
{
GEditor->Trans->DisableObjectSerialization();
FReferencerInformationList ReferencesExcludingUndo;
if ( IsReferenced( RefInfo.Referencer, GARBAGE_COLLECTION_KEEPFLAGS, true, &ReferencesExcludingUndo ) )
{
bIsReferencedInMemoryByUndo = ( ReferencesIncludingUndo.InternalReferences.Num() + ReferencesIncludingUndo.ExternalReferences.Num() ) > ( ReferencesExcludingUndo.InternalReferences.Num() + ReferencesExcludingUndo.ExternalReferences.Num() );
}
GEditor->Trans->EnableObjectSerialization();
}
}
}
}
}
}
static bool GetExternalReferences(UObject* Obj, TArray<FReferencerInformation>& ExternalRefsOut)
{
CollectGarbage(GARBAGE_COLLECTION_KEEPFLAGS);
bool bHasReferences = false;
FReferencerInformationList Refs;
if (IsReferenced(Obj, RF_Native | RF_Public, true, &Refs))
{
ExternalRefsOut = Refs.ExternalReferences;
bHasReferences = true;
}
return bHasReferences;
}
