updateEditingValue method

@protected @override void updateEditingValue(TextEditingValue value)

Requests that this client update its editing state to the given value.

The new value is treated as user input and thus may subject to input formatting.

Implementation

@protected
@override
void updateEditingValue(TextEditingValue value) {
  if (readOnly) return;

  if (_imeComposition == null && !_selection.isCollapsed) {
    _pendingSelectionReplacement = _selection;
  }

  final involvesComposition =
      _imeComposition != null ||
      (value.composing.isValid && !value.composing.isCollapsed);
  if (involvesComposition) {
    _processCompositionValue(value);
    return;
  }

  _suppressImeSync = true;
  _ensureImeProjection();
  _beginImeCompositionUndoGroup(
    value.composing.isValid && !value.composing.isCollapsed,
  );

  final currentText = _imeProjectionText;
  final nextText = value.text;

  if (currentText != nextText) {
    int prefixLength = 0;
    final maxPrefix = currentText.length < nextText.length
        ? currentText.length
        : nextText.length;
    while (prefixLength < maxPrefix &&
        currentText.codeUnitAt(prefixLength) ==
            nextText.codeUnitAt(prefixLength)) {
      prefixLength++;
    }

    int suffixLength = 0;
    final currentTail = currentText.length - prefixLength;
    final nextTail = nextText.length - prefixLength;
    while (suffixLength < currentTail &&
        suffixLength < nextTail &&
        currentText.codeUnitAt(currentText.length - suffixLength - 1) ==
            nextText.codeUnitAt(nextText.length - suffixLength - 1)) {
      suffixLength++;
    }

    final replaceStart = _imeProjectionStartOffset + prefixLength;
    final replaceEnd =
        _imeProjectionStartOffset + currentText.length - suffixLength;
    final replacement = nextText.substring(
      prefixLength,
      nextText.length - suffixLength,
    );

    replaceRange(replaceStart, replaceEnd, replacement);
  }

  _selection = _localImeSelectionToGlobal(value.selection);
  _imeProjectionDirty = true;
  dirtyRegion = TextRange(start: 0, end: _rope.length);
  dirtyLine = null;
  _trackImeComposing(
    value.composing,
    value.selection.isValid
        ? value.selection.extentOffset
        : value.composing.end,
  );
  _endImeCompositionUndoGroupIfIdle();
  _suppressImeSync = false;
  _maybeAcquireFocusForInput();
  notifyListeners();
}