private static List<Range> computeDiff(@NotNull VirtualFile virtualFile,
                                         @NotNull ChangeListManager changeListManager) {
    try {
      Change change = changeListManager.getChange(virtualFile);
      if (change == null) return Collections.emptyList();
      ContentRevision revision = change.getBeforeRevision();
      if (revision == null) return Collections.emptyList();
      String oldContent = revision.getContent();
      if (oldContent == null) return Collections.emptyList();
      String newContent = VfsUtilCore.loadText(virtualFile);
      return ContainerUtil.newArrayList(
        RangesBuilder.compareLines(newContent, oldContent, LineOffsetsUtil.create(newContent), LineOffsetsUtil.create(oldContent))
          .iterateUnchanged());
    }
    catch (VcsException | IOException e) {
      LOG.error("Couldn't load content", e);
      return Collections.emptyList();
    }
  }
private static List<Range> computeDiff(@NotNull VirtualFile virtualFile,
                                         @NotNull ChangeListManager changeListManager)