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);
      }
    }
  }
  @RequiredWriteAction
  @Override
  public void processEvents(@NotNull List<VFileEvent> events) {
    ApplicationManager.getApplication().assertWriteAccessAllowed();

    List<VFileEvent> validated = validateEvents(events);

    BulkFileListener publisher = myEventBus.syncPublisher(VirtualFileManager.VFS_CHANGES);
    publisher.before(validated);

    THashMap<VirtualFile, List<VFileEvent>> parentToChildrenEventsChanges = null;
    for (VFileEvent event : validated) {
      VirtualFile changedParent = null;
      if (event instanceof VFileCreateEvent) {
        changedParent = ((VFileCreateEvent) event).getParent();
        ((VFileCreateEvent) event).resetCache();
      } else if (event instanceof VFileDeleteEvent) {
        changedParent = ((VFileDeleteEvent) event).getFile().getParent();
      }

      if (changedParent != null) {
        if (parentToChildrenEventsChanges == null)
          parentToChildrenEventsChanges = new THashMap<VirtualFile, List<VFileEvent>>();
        List<VFileEvent> parentChildrenChanges = parentToChildrenEventsChanges.get(changedParent);
        if (parentChildrenChanges == null) {
          parentToChildrenEventsChanges.put(
              changedParent, parentChildrenChanges = new SmartList<VFileEvent>());
        }
        parentChildrenChanges.add(event);
      } else {
        applyEvent(event);
      }
    }

    if (parentToChildrenEventsChanges != null) {
      parentToChildrenEventsChanges.forEachEntry(
          new TObjectObjectProcedure<VirtualFile, List<VFileEvent>>() {
            @Override
            public boolean execute(VirtualFile parent, List<VFileEvent> childrenEvents) {
              applyChildrenChangeEvents(parent, childrenEvents);
              return true;
            }
          });
      parentToChildrenEventsChanges.clear();
    }

    publisher.after(validated);
  }
  @Override
  @NotNull
  public VirtualFile[] getLocalRoots() {
    List<VirtualFile> roots = ContainerUtil.newSmartList();

    myRootsLock.readLock().lock();
    try {
      for (NewVirtualFile root : myRoots.values()) {
        if (root.isInLocalFileSystem() && !(root.getFileSystem() instanceof TempFileSystem)) {
          roots.add(root);
        }
      }
    } finally {
      myRootsLock.readLock().unlock();
    }

    return VfsUtilCore.toVirtualFileArray(roots);
  }
  @Override
  @NotNull
  public VirtualFile[] getRoots(@NotNull final NewVirtualFileSystem fs) {
    final List<VirtualFile> roots = new ArrayList<VirtualFile>();

    myRootsLock.readLock().lock();
    try {
      for (NewVirtualFile root : myRoots.values()) {
        if (root.getFileSystem() == fs) {
          roots.add(root);
        }
      }
    } finally {
      myRootsLock.readLock().unlock();
    }

    return VfsUtilCore.toVirtualFileArray(roots);
  }
  @NotNull
  private FSRecords.NameId[] persistAllChildren(
      @NotNull final VirtualFile file, final int id, @NotNull FSRecords.NameId[] current) {
    assert file != mySuperRoot;
    final NewVirtualFileSystem fs = replaceWithNativeFS(getDelegate(file));

    String[] delegateNames = VfsUtil.filterNames(fs.list(file));
    if (delegateNames.length == 0 && current.length > 0) {
      return current;
    }

    Set<String> toAdd = ContainerUtil.newHashSet(delegateNames);
    for (FSRecords.NameId nameId : current) {
      toAdd.remove(nameId.name);
    }

    final TIntArrayList childrenIds = new TIntArrayList(current.length + toAdd.size());
    final List<FSRecords.NameId> nameIds =
        ContainerUtil.newArrayListWithExpectedSize(current.length + toAdd.size());
    for (FSRecords.NameId nameId : current) {
      childrenIds.add(nameId.id);
      nameIds.add(nameId);
    }
    for (String newName : toAdd) {
      FakeVirtualFile child = new FakeVirtualFile(file, newName);
      FileAttributes attributes = fs.getAttributes(child);
      if (attributes != null) {
        int childId = createAndFillRecord(fs, child, id, attributes);
        childrenIds.add(childId);
        nameIds.add(new FSRecords.NameId(childId, FileNameCache.storeName(newName), newName));
      }
    }

    FSRecords.updateList(id, childrenIds.toNativeArray());
    setChildrenCached(id);

    return nameIds.toArray(new FSRecords.NameId[nameIds.size()]);
  }
  @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;
  }