replaceRange method

void replaceRange(int start, int end, String replacement, { bool preserveOldCursor = false, })

Replace a range of text with new text. Used for clipboard operations and text manipulation.

Implementation

void replaceRange(
  int start,
  int end,
  String replacement, {
  bool preserveOldCursor = false,
}) {
  if (_undoController?.isUndoRedoInProgress ?? false) return;

  final selectionBefore = _selection;
  _flushBuffer();
  final safeStart = start.clamp(0, _rope.length);
  final safeEnd = end.clamp(safeStart, _rope.length);
  final deletedText = safeStart < safeEnd
      ? _rope.substring(safeStart, safeEnd)
      : '';

  if (safeStart < safeEnd) {
    _rope.delete(safeStart, safeEnd);
  }
  if (replacement.isNotEmpty) {
    _rope.insert(safeStart, replacement);
  }
  _currentVersion++;
  TextSelection newSelection;
  if (preserveOldCursor) {
    final delta = replacement.length - (safeEnd - safeStart);

    int mapOffset(int offset) {
      if (offset <= safeStart) return offset;
      if (offset >= safeEnd) return (offset + delta).clamp(0, _rope.length);
      final relative = offset - safeStart;
      final mapped = safeStart + relative.clamp(0, replacement.length);
      return mapped.clamp(0, _rope.length);
    }

    final base = mapOffset(selectionBefore.baseOffset);
    final extent = mapOffset(selectionBefore.extentOffset);
    newSelection = TextSelection(baseOffset: base, extentOffset: extent);
  } else {
    newSelection = TextSelection.collapsed(
      offset: safeStart + replacement.length,
    );
  }
  _selection = newSelection;
  dirtyLine = _rope.getLineAtOffset(safeStart);
  dirtyRegion = TextRange(
    start: safeStart,
    end: safeStart + replacement.length,
  );

  if (deletedText.isNotEmpty && replacement.isNotEmpty) {
    _recordReplacement(
      safeStart,
      deletedText,
      replacement,
      selectionBefore,
      _selection,
    );
  } else if (deletedText.isNotEmpty) {
    _recordDeletion(safeStart, deletedText, selectionBefore, _selection);
  } else if (replacement.isNotEmpty) {
    _recordInsertion(safeStart, replacement, selectionBefore, _selection);
  }

  if (connection != null && connection!.attached) {
    _lastSentText = text;
    _lastSentSelection = _selection;
    connection!.setEditingState(
      TextEditingValue(text: _lastSentText!, selection: _selection),
    );
  }

  notifyListeners();
}