getFieldDataNative method

Implementation

@override
bool getFieldDataNative(TField field, TValueBuffer? buffer) {
  final TRecordBuffer? rec;
  switch (state) {
    case TDataSetState.dsCalcFields:
      rec = calcBuffer;
      break;
    case TDataSetState.dsOldValue:
      // @@@ fix: while applyRecUpdate() is running (_applyingUpdate is
      // non-null), _applyingUpdate.oldValues must be read first -- that's
      // the "real" old-value snapshot for this pending update
      // (internalDelete()/internalPost() both correctly save it, and
      // applyUpdates()'s loop has already assigned it to
      // _applyingUpdate). The old code only recognized _oldValueBuffer
      // (only internalEdit() sets it, and internalPost() clears it to
      // null once used) or fell back to activeBuffer() (whatever record
      // the cursor currently points at) -- after a DELETE removes a
      // record from _records, the resulting array shift means the next
      // record ends up at that cursor position; and even for a MODIFY,
      // _oldValueBuffer has usually already been cleared by
      // internalPost() by this point. Either way, this read the old
      // values of "whatever record the cursor currently points at"
      // instead of "the record actually being updated", so the WHERE
      // clause built from it targeted the wrong record (e.g. deleting
      // the next record instead).
      if (_applyingUpdate != null) {
        rec = TRecordBuffer()..fieldData.addAll(_applyingUpdate!.oldValues);
      } else {
        rec = _oldValueBuffer ?? activeBuffer();
      }
      break;
    default:
      rec = activeBuffer();
  }
  if (rec == null) return false;
  final key = field.fieldName.toUpperCase();
  final dynamic v;
  if (field.fieldKind == TFieldKind.fkCalculated ||
      field.fieldKind == TFieldKind.fkLookup) {
    if (!rec.calcData.containsKey(key)) return false;
    v = rec.calcData[key];
  } else {
    if (!rec.fieldData.containsKey(key)) return false;
    v = rec.fieldData[key];
  }
  if (v == null) return false;
  if (buffer != null) buffer.value = v;
  return true;
}