synchronized void clearPointerCaches(String url, VirtualFilePointerListener listener) {
   TreeMap<String, VirtualFilePointerImpl> urlToPointer = myUrlToPointerMaps.get(listener);
   if (urlToPointer == null && ApplicationManager.getApplication().isUnitTestMode()) return;
   assert urlToPointer != null;
   urlToPointer.remove(VfsUtil.urlToPath(url));
   if (urlToPointer.isEmpty()) {
     myUrlToPointerMaps.remove(listener);
   }
 }