else return NULL;
}  nsresult err = nsMimeNewURI(&base, base_url, nsnull); if (err != NS_OK) return nsnull;  nsIURI    *url = nsnull; err = nsMimeNewURI(&url, relative_url, base); if (err != NS_OK) goto done;  err = url->GetSpec(&retString); if (err) { retString = nsnull; goto done; }  done: NS_IF_RELEASE(url); NS_IF_RELEASE(base); return retString;
MakeAbsoluteURL(char * absolute_url, char * relative_url){  nsMimeURLUtils myUtil;  char           *retString;  if (NS_SUCCEEDED(myUtil.MakeAbsoluteURL(absolute_url, relative_url, &retString)))    return retString;  else    return NULL;}