transaction<T> method

@override Future<T> transaction<T>(Future<T> callback(), { Duration retryDelay = const Duration(milliseconds: 100), Future<void> onSuccess(T result)?, Future<void> onFailure(dynamic error)?, Future<void> onFinally()?, String? isolationLevel, })

Executes a transactional block with retry, success/failure hooks.

• callback is the block of code to run inside a transaction.
• retryDelay sets the delay between retries.

Hooks:

• onSuccess called when the transaction commits successfully.
• onFailure called if the transaction throws an error.
• onFinally always called after transaction completes.

Implementation

@override
Future<T> transaction<T>(
  Future<T> Function() callback, {
  Duration retryDelay = const Duration(milliseconds: 100),
  Future<void> Function(T result)? onSuccess,
  Future<void> Function(dynamic error)? onFailure,
  Future<void> Function()? onFinally,
  String? isolationLevel,
}) async {
  if (!isConnected) {
    await connect();
  }

  try {
    if (isolationLevel != null) {
      await execute('SET TRANSACTION ISOLATION LEVEL $isolationLevel');
    }
    await execute('START TRANSACTION');
    final result = await callback();
    await execute('COMMIT');

    if (onSuccess != null) {
      await onSuccess(result);
    }

    return result;
  } catch (e) {
    try {
      await execute('ROLLBACK');
    } catch (_) {
      // Ignore rollback errors if connection is lost
    }

    if (onFailure != null) await onFailure(e);
    rethrow;
  } finally {
    if (onFinally != null) await onFinally();
  }
}