transaction<R> method

@override Future<R> transaction<R>(Future<R> body(KeyStoreTxn<String, AtData, AtMetaData?> txn))

Run body as a transaction. Mutations performed via the supplied handle are buffered in memory and applied in body order on successful completion; if the body throws, the buffer is dropped and the exception propagates.

Hive impls provide best-effort atomicity; a future SQL impl will provide true atomicity.

Implementation

@override
Future<R> transaction<R>(
  Future<R> Function(KeyStoreTxn<String, AtData, AtMetaData?> txn) body,
) async {
  final txn = _HiveAtKeyValueStoreTxn(this);
  final R result;
  try {
    result = await body(txn);
  } catch (_) {
    // body threw — drop buffered ops, propagate.
    rethrow;
  }
  // Body succeeded — apply buffered ops in insertion order. Each
  // applied op fires its own `changes` event via the standard
  // putAll / remove paths.
  for (final entry in txn._ops.values) {
    await entry.apply(this);
  }
  return result;
}