@Nullable
  @Override
  public TextBlockTransferableData collectTransferableData(
      PsiFile file, Editor editor, int[] startOffsets, int[] endOffsets) {
    if (!Registry.is("editor.richcopy.enable")) {
      return null;
    }

    try {
      for (TextWithMarkupBuilder builder : myBuilders) {
        builder.reset();
      }
      SelectionModel selectionModel = editor.getSelectionModel();
      if (selectionModel.hasBlockSelection()) {
        return null; // unsupported legacy mode
      }

      RichCopySettings settings = RichCopySettings.getInstance();
      List<Caret> carets = editor.getCaretModel().getAllCarets();
      Caret firstCaret = carets.get(0);
      final int indentSymbolsToStrip;
      final int firstLineStartOffset;
      if (settings.isStripIndents() && carets.size() == 1) {
        Pair<Integer, Integer> p =
            calcIndentSymbolsToStrip(
                editor.getDocument(), firstCaret.getSelectionStart(), firstCaret.getSelectionEnd());
        firstLineStartOffset = p.first;
        indentSymbolsToStrip = p.second;
      } else {
        firstLineStartOffset = firstCaret.getSelectionStart();
        indentSymbolsToStrip = 0;
      }
      logInitial(editor, startOffsets, endOffsets, indentSymbolsToStrip, firstLineStartOffset);
      CharSequence text = editor.getDocument().getCharsSequence();
      EditorColorsScheme schemeToUse = settings.getColorsScheme(editor.getColorsScheme());
      EditorHighlighter highlighter =
          HighlighterFactory.createHighlighter(
              file.getVirtualFile(), schemeToUse, file.getProject());
      highlighter.setText(text);
      MarkupModel markupModel =
          DocumentMarkupModel.forDocument(editor.getDocument(), file.getProject(), false);
      Context context = new Context(text, schemeToUse, indentSymbolsToStrip);
      int shift = 0;
      int endOffset = 0;
      Caret prevCaret = null;

      for (Caret caret : carets) {
        int caretSelectionStart = caret.getSelectionStart();
        int caretSelectionEnd = caret.getSelectionEnd();
        int startOffsetToUse;
        if (caret == firstCaret) {
          startOffsetToUse = firstLineStartOffset;
        } else {
          startOffsetToUse = caretSelectionStart;
          assert prevCaret != null;
          String prevCaretSelectedText = prevCaret.getSelectedText();
          // Block selection fills short lines by white spaces.
          int fillStringLength =
              prevCaretSelectedText == null
                  ? 0
                  : prevCaretSelectedText.length()
                      - (prevCaret.getSelectionEnd() - prevCaret.getSelectionStart());
          int endLineOffset = endOffset + shift + fillStringLength;
          context.builder.addText(endLineOffset, endLineOffset + 1);
          shift++; // Block selection ends '\n' at line end
          shift += fillStringLength;
        }
        shift += endOffset - caretSelectionStart;
        endOffset = caretSelectionEnd;
        context.reset(shift);
        prevCaret = caret;
        if (endOffset <= startOffsetToUse) {
          continue;
        }
        MarkupIterator markupIterator =
            new MarkupIterator(
                text,
                new CompositeRangeIterator(
                    schemeToUse,
                    new HighlighterRangeIterator(highlighter, startOffsetToUse, endOffset),
                    new MarkupModelRangeIterator(
                        markupModel, schemeToUse, startOffsetToUse, endOffset)),
                schemeToUse);
        try {
          context.iterate(markupIterator, endOffset);
        } finally {
          markupIterator.dispose();
        }
      }
      SyntaxInfo syntaxInfo = context.finish();
      logSyntaxInfo(syntaxInfo);

      for (TextWithMarkupBuilder builder : myBuilders) {
        builder.build(syntaxInfo);
      }
    } catch (Exception e) {
      // catching the exception so that the rest of copy/paste functionality can still work fine
      LOG.error(e);
    }
    return null;
  }