catch error from blank xml file - c++

Question

I am using C++ and I read in and parse an XML file. If the file does not exist it gets created and if it does exist and has correctly formatted data in it there no errors. My problem is when I try to read in a blank XML file (completely blank not even the header) my program crashes as it tries to process the data from the XML file. I need to be able to catch the error before that happen so I can wright the correct settings back to the file or remove the file and make a new one. Is there a way to do this such as checking to see if a node is NULL? And how would I do it?
class XmlDomErrorHandler : public HandlerBase
{
public:
void fatalError(const SAXParseException &exc) {
printf("Fatal parsing error at line %d\n", (int)exc.getLineNumber());
exit(-1);
}
};
void XmlParentNode::refreshAllNodes()
{
m_children.clear();
m_childrernByName.clear();
for(int j =0; j < getInnerParentNode()->getChildNodes()->getLength(); ++j) //crashes here on first pass if xmlfile is empty
{
//code that is never reached
}
XmlDocument::XmlDocument(String name):
XmlParentNode(),
m_pOwner(NULL)
{
if(XmlManager::Get()->initialize())
{
XMLCh* xmlName = XMLString::transcode(StringA(name));
setInnerNode(XmlManager::Get()->getDOMImplementation()->createDocument(NULL, xmlName , NULL));
XMLString::release(&xmlName);
}
}
XmlDocument::XmlDocument(FilePath path):
XmlParentNode(),
m_pOwner(NULL)
{
XMLCh* xmlPath = XMLString::transcode(StringA(path.ToString()));
XercesDOMParser* parser = new XercesDOMParser();
parser->parse(xmlPath);
if(!parser)
{
ErrorHandler* errorHandler = (ErrorHandler*) new XmlDomErrorHandler();
parser->setErrorHandler(errorHandler);
}
DOMDocument* p_Doc= parser->getDocument();
m_pOwner = parser;
XMLString::release(&xmlPath);
if (p_Doc!= NULL)
{
setInnerNode(p_Doc);
refreshAllNodes();
}
}
Sadly I can't stop people for editing the XML file as users need access to it so they can edit settings.
I am new to XML so maybe I'm missing something easy.
I have been using XML Parsing with DOM and a guide I found here

Answer 1

I solved the problem.
I added a check before the for loop that crashed.
if(getInnerParentNode() && getInnerParentNode()->getChildNodes())
{
for(int j =0; j < getInnerParentNode()->getChildNodes()->getLength(); ++j) //was crashing here on first pass if xmlfile is empty
{
//code that was not being reached
}
}