if (aString.IsEmpty()) { NS_ERROR("Atom requested for empty string!");  return nsnull; }
NS_COM nsIAtom* NS_NewAtom( const nsAString& aString ){  AtomTableEntry *he = GetAtomHashEntry(aString);  AtomImpl* atom = he->mAtom;  if (!atom) {    atom = new (aString) AtomImpl();    he->mAtom = atom;    if (!atom) {      PL_DHashTableRawRemove(&gAtomTable, he);      return nsnull;    }  }  NS_ADDREF(atom);  return atom;}