class System

QueueTest.php in drupal/core/modules/system/lib/Drupal/system/Tests/Queue/QueueTest.php

Definition of Drupal\system\Tests\Queue\QueueTest.

AccessDeniedTest::getInfo in drupal/core/modules/system/lib/Drupal/system/Tests/System/AccessDeniedTest.php

AdminMetaTagTest::getInfo in drupal/core/modules/system/lib/Drupal/system/Tests/System/AdminMetaTagTest.php

Implement getInfo().

AdminMetaTagTest::testMetaTag in drupal/core/modules/system/lib/Drupal/system/Tests/System/AdminMetaTagTest.php

Verify that the meta tag HTML is generated correctly.

AdminTest::getInfo in drupal/core/modules/system/lib/Drupal/system/Tests/System/AdminTest.php

ArrayUnitTest::getInfo in drupal/core/modules/system/lib/Drupal/system/Tests/Common/ArrayUnitTest.php

... See full list

class System implements ReliableQueueInterface {

  /**
   * The name of the queue this instance is working with.
   *
   * @var string
   */
  protected $name;

  /**
   * Constructs a System object.
   *
   * @param string $name
   *   An arbitrary string. The name of the queue to work with.
   */
  public function __construct($name) {
    $this->name = $name;
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::createItem().
   */
  public function createItem($data) {

    // During a Drupal 6.x to 8.x update, drupal_get_schema() does not contain
    // the queue table yet, so we cannot rely on drupal_write_record().
    $query = db_insert('queue')
      ->fields(array(
      'name' => $this->name,
      'data' => serialize($data),
      // We cannot rely on REQUEST_TIME because many items might be created
      // by a single request which takes longer than 1 second.
      'created' => time(),
    ));
    return (bool) $query
      ->execute();
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::numberOfItems().
   */
  public function numberOfItems() {
    return db_query('SELECT COUNT(item_id) FROM {queue} WHERE name = :name', array(
      ':name' => $this->name,
    ))
      ->fetchField();
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::claimItem().
   */
  public function claimItem($lease_time = 30) {

    // Claim an item by updating its expire fields. If claim is not successful
    // another thread may have claimed the item in the meantime. Therefore loop
    // until an item is successfully claimed or we are reasonably sure there
    // are no unclaimed items left.
    while (TRUE) {
      $item = db_query_range('SELECT data, item_id FROM {queue} q WHERE expire = 0 AND name = :name ORDER BY created ASC', 0, 1, array(
        ':name' => $this->name,
      ))
        ->fetchObject();
      if ($item) {

        // Try to update the item. Only one thread can succeed in UPDATEing the
        // same row. We cannot rely on REQUEST_TIME because items might be
        // claimed by a single consumer which runs longer than 1 second. If we
        // continue to use REQUEST_TIME instead of the current time(), we steal
        // time from the lease, and will tend to reset items before the lease
        // should really expire.
        $update = db_update('queue')
          ->fields(array(
          'expire' => time() + $lease_time,
        ))
          ->condition('item_id', $item->item_id)
          ->condition('expire', 0);

        // If there are affected rows, this update succeeded.
        if ($update
          ->execute()) {
          $item->data = unserialize($item->data);
          return $item;
        }
      }
      else {

        // No items currently available to claim.
        return FALSE;
      }
    }
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::releaseItem().
   */
  public function releaseItem($item) {
    $update = db_update('queue')
      ->fields(array(
      'expire' => 0,
    ))
      ->condition('item_id', $item->item_id);
    return $update
      ->execute();
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::deleteItem().
   */
  public function deleteItem($item) {
    db_delete('queue')
      ->condition('item_id', $item->item_id)
      ->execute();
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::createQueue().
   */
  public function createQueue() {

    // All tasks are stored in a single database table (which is created when
    // Drupal is first installed) so there is nothing we need to do to create
    // a new queue.
  }

  /**
   * Implements Drupal\Core\Queue\QueueInterface::deleteQueue().
   */
  public function deleteQueue() {
    db_delete('queue')
      ->condition('name', $this->name)
      ->execute();
  }

}