if (prefixLen == 0) {
if (prefixLen <= 0) {
RDFContentSinkImpl::IsXMLNSDirective(const nsString& aAttributeKey, nsIAtom** aPrefix){    // Look for `xmlns' at the start of the attribute name    PRInt32 offset = aAttributeKey.Find(kNameSpaceDef);    if (offset != 0)        return PR_FALSE;    PRInt32 prefixLen = aAttributeKey.Length() - sizeof(kNameSpaceDef);    if (prefixLen == 0) {        // they're setting the default namespace; leave `prefix'        // as nsnull.    }    else {        // make sure there's a `:' character        if (aAttributeKey[sizeof(kNameSpaceDef) - 1] != kNameSpaceSeparator)            return PR_FALSE;        // if the caller wants the prefix back, compute it for them.        if (aPrefix) {            nsAutoString prefixStr;            aAttributeKey.Right(prefixStr, prefixLen);            *aPrefix = NS_NewAtom(prefixStr);        }    }    return PR_TRUE;}