<?php

/**

 * @file

 * Queue handlers used by the Batch API.

 *

 * These implementations:

 * - Ensure FIFO ordering.

 * - Allow an item to be repeatedly claimed until it is actually deleted (no

 *   notion of lease time or 'expire' date), to allow multipass operations.

 */

/**

 * Defines a batch queue.

 *

 * Stale items from failed batches are cleaned from the {queue} table on cron

 * using the 'created' date.

 */

class BatchQueue extends SystemQueue {

  /**

   * Overrides SystemQueue::claimItem().

   *

   * Unlike SystemQueue::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) {

    $item = db_query_range('SELECT data, item_id FROM {queue} q WHERE name = :name ORDER BY item_id ASC', 0, 1, array(':name' => $this->name))->fetchObject();

    if ($item) {

      $item->data = unserialize($item->data);

      return $item;

    }

    return FALSE;

  }

  /**

   * Retrieves all remaining items in the queue.

   *

   * This is specific to Batch API and is not part of the DrupalQueueInterface.

   */

  public function getAllItems() {

    $result = array();

    $items = db_query('SELECT data FROM {queue} q WHERE name = :name ORDER BY item_id ASC', array(':name' => $this->name))->fetchAll();

    foreach ($items as $item) {

      $result[] = unserialize($item->data);

    }

    return $result;

  }

}

/**

 * Defines a batch queue for non-progressive batches.

 */

class BatchMemoryQueue extends MemoryQueue {

  /**

   * Overrides MemoryQueue::claimItem().

   *

   * Unlike MemoryQueue::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) {

    if (!empty($this->queue)) {

      reset($this->queue);

      return current($this->queue);

    }

    return FALSE;

  }

  /**

   * Retrieves all remaining items in the queue.

   *

   * This is specific to Batch API and is not part of the DrupalQueueInterface.

   */

  public function getAllItems() {

    $result = array();

    foreach ($this->queue as $item) {

      $result[] = $item->data;

    }

    return $result;

  }

}