private void applyChildrenChangeEvents(VirtualFile parent, List<VFileEvent> events) {
    final NewVirtualFileSystem delegate = getDelegate(parent);
    TIntArrayList childrenIdsUpdated = new TIntArrayList();
    List<VirtualFile> childrenToBeUpdated = new SmartList<VirtualFile>();

    assert parent != null && parent != mySuperRoot;
    final int parentId = getFileId(parent);
    assert parentId != 0;
    TIntHashSet parentChildrenIds = new TIntHashSet(FSRecords.list(parentId));
    boolean hasRemovedChildren = false;

    for (VFileEvent event : events) {
      if (event instanceof VFileCreateEvent) {
        String name = ((VFileCreateEvent) event).getChildName();
        final VirtualFile fake = new FakeVirtualFile(parent, name);
        final FileAttributes attributes = delegate.getAttributes(fake);

        if (attributes != null) {
          final int childId = createAndFillRecord(delegate, fake, parentId, attributes);
          assert parent instanceof VirtualDirectoryImpl : parent;
          final VirtualDirectoryImpl dir = (VirtualDirectoryImpl) parent;
          VirtualFileSystemEntry child = dir.createChild(name, childId, dir.getFileSystem());
          childrenToBeUpdated.add(child);
          childrenIdsUpdated.add(childId);
          parentChildrenIds.add(childId);
        }
      } else if (event instanceof VFileDeleteEvent) {
        VirtualFile file = ((VFileDeleteEvent) event).getFile();
        if (!file.exists()) {
          LOG.error("Deleting a file, which does not exist: " + file.getPath());
          continue;
        }

        hasRemovedChildren = true;
        int id = getFileId(file);

        childrenToBeUpdated.add(file);
        childrenIdsUpdated.add(-id);
        parentChildrenIds.remove(id);
      }
    }

    FSRecords.updateList(parentId, parentChildrenIds.toArray());

    if (hasRemovedChildren) clearIdCache();
    VirtualDirectoryImpl parentImpl = (VirtualDirectoryImpl) parent;

    for (int i = 0, len = childrenIdsUpdated.size(); i < len; ++i) {
      final int childId = childrenIdsUpdated.get(i);
      final VirtualFile childFile = childrenToBeUpdated.get(i);

      if (childId > 0) {
        parentImpl.addChild((VirtualFileSystemEntry) childFile);
      } else {
        FSRecords.deleteRecordRecursively(-childId);
        parentImpl.removeChild(childFile);
        invalidateSubtree(childFile);
      }
    }
  }
  @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;
  }