class DatabaseTransaction

backdrop_class_list in includes/bootstrap.classes.inc

Lists all the classes used by Backdrop core.

DatabaseConnection::startTransaction in includes/database/database.inc

Returns a new DatabaseTransaction object on this connection.

class DatabaseTransaction {

  /**
   * The connection object for this transaction.
   *
   * @var DatabaseConnection
   */
  protected $connection;

  /**
   * A boolean value to indicate whether this transaction has been rolled back.
   *
   * @var Boolean
   */
  protected $rolledBack = FALSE;

  /**
   * The name of the transaction.
   *
   * This is used to label the transaction savepoint. It will be overridden to
   * 'backdrop_transaction' if there is no transaction depth.
   */
  protected $name;

  public function __construct(DatabaseConnection $connection, $name = NULL) {
    $this->connection = $connection;
    // If there is no transaction depth, then no transaction has started. Name
    // the transaction 'backdrop_transaction'.
    if (!$depth = $connection->transactionDepth()) {
      $this->name = 'backdrop_transaction';
    }
    // Within transactions, savepoints are used. Each savepoint requires a
    // name. So if no name is present we need to create one.
    elseif (!$name) {
      $this->name = 'savepoint_' . $depth;
    }
    else {
      $this->name = $name;
    }
    $this->connection->pushTransaction($this->name);
  }

  public function __destruct() {
    // If we rolled back then the transaction would have already been popped.
    if (!$this->rolledBack) {
      $this->connection->popTransaction($this->name);
    }
  }

  /**
   * Retrieves the name of the transaction or savepoint.
   */
  public function name() {
    return $this->name;
  }

  /**
   * Rolls back the current transaction.
   *
   * This is just a wrapper method to rollback whatever transaction stack we are
   * currently in, which is managed by the connection object itself. Note that
   * logging (preferable with watchdog_exception()) needs to happen after a
   * transaction has been rolled back or the log messages will be rolled back
   * too.
   *
   * @see DatabaseConnection::rollback()
   * @see watchdog_exception()
   */
  public function rollback() {
    $this->rolledBack = TRUE;
    $this->connection->rollback($this->name);
  }
}