// returns list of resolved files if updated successfully, or null if write action or dumb mode
  // started
  private int[] processFile(
      @NotNull final VirtualFile file, int fileId, @NotNull final ProgressIndicator indicator) {
    final TIntHashSet forward;
    try {
      forward = calcForwardRefs(file, indicator);
    } catch (IndexNotReadyException e) {
      return null;
    } catch (ApplicationUtil.CannotRunReadActionException e) {
      return null;
    } catch (ProcessCanceledException e) {
      throw e;
    } catch (Exception e) {
      log(ExceptionUtil.getThrowableText(e));
      flushLog();
      return null;
    }

    int[] forwardIds = forward.toArray();
    fileIsResolved.set(fileId);
    logf(
        "  ---- " + file.getPresentableUrl() + " processed. forwardIds: " + toVfString(forwardIds));
    for (Listener listener : myListeners) {
      listener.fileResolved(file);
    }
    return forwardIds;
  }
  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);
      }
    }
  }