class KeyValueDatabaseExpirableFactory

class KeyValueDatabaseExpirableFactory implements KeyValueExpirableFactoryInterface {
    
    /**
     * Holds references to each instantiation so they can be terminated.
     *
     * @var \Drupal\Core\KeyValueStore\DatabaseStorageExpirable[]
     */
    protected $storages = [];
    
    /**
     * The serialization class to use.
     *
     * @var \Drupal\Component\Serialization\SerializationInterface
     */
    protected $serializer;
    
    /**
     * The database connection.
     *
     * @var \Drupal\Core\Database\Connection
     */
    protected $connection;
    
    /**
     * Constructs this factory object.
     *
     * @param \Drupal\Component\Serialization\SerializationInterface $serializer
     *   The serialization class to use.
     * @param \Drupal\Core\Database\Connection $connection
     *   The Connection object containing the key-value tables.
     */
    public function __construct(SerializationInterface $serializer, Connection $connection) {
        $this->serializer = $serializer;
        $this->connection = $connection;
    }
    
    /**
     * {@inheritdoc}
     */
    public function get($collection) {
        if (!isset($this->storages[$collection])) {
            $this->storages[$collection] = new DatabaseStorageExpirable($collection, $this->serializer, $this->connection);
        }
        return $this->storages[$collection];
    }
    
    /**
     * Deletes expired items.
     */
    public function garbageCollection() {
        try {
            $this->connection
                ->delete('key_value_expire')
                ->condition('expire', REQUEST_TIME, '<')
                ->execute();
        } catch (\Exception $e) {
            $this->catchException($e);
        }
    }
    
    /**
     * Act on an exception when the table might not have been created.
     *
     * If the table does not yet exist, that's fine, but if the table exists and
     * yet the query failed, then the exception needs to propagate.
     *
     * @param \Exception $e
     *   The exception.
     *
     * @throws \Exception
     */
    protected function catchException(\Exception $e) {
        if ($this->connection
            ->schema()
            ->tableExists('key_value_expire')) {
            throw $e;
        }
    }

}