Problem with DuplicateObject() and XmlParser

Development Programming & Scripting C++
1

Hello everyone, I’m currently trying to expose some of UE4’s XmlParser code to blueprints, but I’m running into some problems. I think my problem is with DuplicateObject() not duplicating the object correctly? I am unsure if FXmlFile will duplicate with that function or not, but when I test it, it crashes. Here’s my code.


UCLASS(BlueprintType)
class EASYXML_API UEasyXMLObject : public UObject
{
	GENERATED_BODY()
	
public:
	UEasyXMLObject();
	~UEasyXMLObject();

	void InitObject(FString XMLString);


// Blueprint functions
public:
	UFUNCTION(BlueprintCallable, Category = "EasyXML")
		UEasyXMLObject* GetFirstChildNode();

//private:
	FXmlFile EasyXMLFile;
	const FXmlNode* CurrentNode;
};

void UEasyXMLObject::InitObject(FString XMLString)
{
	// Load the XML file into EasyXMLFile
	EasyXMLFile.LoadFile(XMLString, EConstructMethod::Type::ConstructFromBuffer);

	CurrentNode = EasyXMLFile.GetRootNode();
}

UEasyXMLObject* UEasyXMLObject::GetFirstChildNode()
{
	UEasyXMLObject* temp = DuplicateObject<UEasyXMLObject>(this, NULL);
	temp->CurrentNode = temp->CurrentNode->GetFirstChildNode(); // crashes with this line, I believe
	return temp;
}

I have tried using pointers as well, so instead of just FXmlFile, i used FXmlFile* and deleting the memory manually in BeginDestroy() or the destructor, but I had zero luck! I’m bashing my head against my keyboard trying to figure this out. Does anyone have any suggestions? Thank you so much for the help!

2

I’ve narrowed it down but still cant figure it out…

Problematic code:


temp->CurrentNode = temp->CurrentNode->GetFirstChildNode();

Current Node is of type const FXmlNode* and **GetFirstChildNode() *also returns a const FXmlNode, so I’m not sure why this isn’t working. Does anyone have any insight as to why this is causing a crash? Am I doing something stupidly obvious?

3

Hi metiri,

is temp->CurrentNode null perhaps?
I didn’t run it, but this looks to me as if currentNode isn’t set yet.
I’d try to set temp.CurrentNode = temp.GetRoot (or something like that, dont have source at hand), then you can get other child nodes.