@NotNull private static List<VFileEvent> validateEvents(@NotNull List<VFileEvent> events) { final List<EventWrapper> deletionEvents = ContainerUtil.newArrayList(); for (int i = 0, size = events.size(); i < size; i++) { final VFileEvent event = events.get(i); if (event instanceof VFileDeleteEvent && event.isValid()) { deletionEvents.add(new EventWrapper((VFileDeleteEvent) event, i)); } } final TIntHashSet invalidIDs; if (deletionEvents.isEmpty()) { invalidIDs = EmptyIntHashSet.INSTANCE; } else { ContainerUtil.quickSort(deletionEvents, DEPTH_COMPARATOR); invalidIDs = new TIntHashSet(deletionEvents.size()); final Set<VirtualFile> dirsToBeDeleted = new THashSet<VirtualFile>(deletionEvents.size()); nextEvent: for (EventWrapper wrapper : deletionEvents) { final VirtualFile candidate = wrapper.event.getFile(); VirtualFile parent = candidate; while (parent != null) { if (dirsToBeDeleted.contains(parent)) { invalidIDs.add(wrapper.id); continue nextEvent; } parent = parent.getParent(); } if (candidate.isDirectory()) { dirsToBeDeleted.add(candidate); } } } final List<VFileEvent> filtered = new ArrayList<VFileEvent>(events.size() - invalidIDs.size()); for (int i = 0, size = events.size(); i < size; i++) { final VFileEvent event = events.get(i); if (event.isValid() && !(event instanceof VFileDeleteEvent && invalidIDs.contains(i))) { filtered.add(event); } } return filtered; }