private void createOldFragmentLineSetIfNeeded() {
    if (myOldFragmentLineSet != null) {
      return;
    }
    CharSequence newText = getDocument().getImmutableCharSequence();
    CharSequence oldFragment = getOldFragment();
    myOldFragmentLineSetStart = getOffset();
    if (myOldFragmentLineSetStart > 0 && newText.charAt(myOldFragmentLineSetStart - 1) == '\r') {
      myOldFragmentLineSetStart--;
      oldFragment = new MergingCharSequence("\r", oldFragment);
    }
    int newChangeEnd = getOffset() + getNewLength();
    if (newChangeEnd < newText.length() && newText.charAt(newChangeEnd) == '\n') {
      oldFragment = new MergingCharSequence(oldFragment, "\n");
    }
    myOldFragmentLineSet = LineSet.createLineSet(oldFragment);
  }
private void createOldFragmentLineSetIfNeeded()