Batch.php

<?php

namespace Drupal\Core\Queue;


/**
 * Defines a batch queue handler used by the Batch API.
 *
 * This implementation:
 * - Ensures FIFO ordering.
 * - Allows an item to be repeatedly claimed until it is actually deleted (no
 *   notion of lease time or 'expire' date), to allow multipass operations.
 *
 * Stale items from failed batches are cleaned from the {queue} table on cron
 * using the 'created' date.
 *
 * @ingroup queue
 */
class Batch extends DatabaseQueue {
    
    /**
     * Overrides \Drupal\Core\Queue\DatabaseQueue::claimItem().
     *
     * Unlike \Drupal\Core\Queue\DatabaseQueue::claimItem(), this method provides
     * a default lease time of 0 (no expiration) instead of 30. This allows the
     * item to be claimed repeatedly until it is deleted.
     */
    public function claimItem($lease_time = 0) {
        try {
            $item = $this->connection
                ->queryRange('SELECT [data], [item_id] FROM {queue} q WHERE [name] = :name ORDER BY [item_id] ASC', 0, 1, [
                ':name' => $this->name,
            ])
                ->fetchObject();
            if ($item) {
                $item->data = unserialize($item->data);
                return $item;
            }
        } catch (\Exception $e) {
            $this->catchException($e);
        }
        return FALSE;
    }
    
    /**
     * Retrieves all remaining items in the queue.
     *
     * This is specific to Batch API and is not part of the
     * \Drupal\Core\Queue\QueueInterface.
     *
     * @return array
     *   An array of queue items.
     */
    public function getAllItems() {
        $result = [];
        try {
            $items = $this->connection
                ->query('SELECT [data] FROM {queue} q WHERE [name] = :name ORDER BY [item_id] ASC', [
                ':name' => $this->name,
            ])
                ->fetchAll();
            foreach ($items as $item) {
                $result[] = unserialize($item->data);
            }
        } catch (\Exception $e) {
            $this->catchException($e);
        }
        return $result;
    }

}