class TransactionManager

class TransactionManager extends TransactionManagerBase {
  
  /**
   * {@inheritdoc}
   */
  protected function beginClientTransaction() : bool {
    return $this->connection
      ->getClientConnection()
      ->begin_transaction();
  }
  
  /**
   * {@inheritdoc}
   */
  protected function addClientSavepoint(string $name) : bool {
    return $this->connection
      ->getClientConnection()
      ->savepoint($name);
  }
  
  /**
   * {@inheritdoc}
   */
  protected function rollbackClientSavepoint(string $name) : bool {
    // Mysqli does not have a rollback_to_savepoint method, and it does not
    // allow a prepared statement for 'ROLLBACK TO SAVEPOINT', so we need to
    // fallback to querying on the client connection directly.
    try {
      return (bool) $this->connection
        ->getClientConnection()
        ->query('ROLLBACK TO SAVEPOINT ' . $name);
    } catch (\mysqli_sql_exception) {
      // If the rollback failed, most likely the savepoint was not there
      // because the transaction is no longer active. In this case we void the
      // transaction stack.
      $this->voidClientTransaction();
      return TRUE;
    }
  }
  
  /**
   * {@inheritdoc}
   */
  protected function releaseClientSavepoint(string $name) : bool {
    return $this->connection
      ->getClientConnection()
      ->release_savepoint($name);
  }
  
  /**
   * {@inheritdoc}
   */
  protected function rollbackClientTransaction() : bool {
    // Note: mysqli::rollback() returns TRUE if there's no active transaction.
    // This is diverging from PDO MySql. A PHP bug report exists.
    // @see https://bugs.php.net/bug.php?id=81533.
    $clientRollback = $this->connection
      ->getClientConnection()
      ->rollBack();
    $this->setConnectionTransactionState($clientRollback ? ClientConnectionTransactionState::RolledBack : ClientConnectionTransactionState::RollbackFailed);
    return $clientRollback;
  }
  
  /**
   * {@inheritdoc}
   */
  protected function commitClientTransaction() : bool {
    $clientCommit = $this->connection
      ->getClientConnection()
      ->commit();
    $this->setConnectionTransactionState($clientCommit ? ClientConnectionTransactionState::Committed : ClientConnectionTransactionState::CommitFailed);
    return $clientCommit;
  }

}