interface UpdateProcessorInterface

interface UpdateProcessorInterface {
    
    /**
     * Claims an item in the update fetch queue for processing.
     *
     * @return bool|object
     *   On success we return an item object. If the queue is unable to claim an
     *   item it returns false.
     *
     * @see \Drupal\Core\Queue\QueueInterface::claimItem()
     */
    public function claimQueueItem();
    
    /**
     * Attempts to drain the queue of tasks for release history data to fetch.
     */
    public function fetchData();
    
    /**
     * Adds a task to the queue for fetching release history data for a project.
     *
     * We only create a new fetch task if there's no task already in the queue for
     * this particular project (based on 'update_fetch_task' key-value
     * collection).
     *
     * @param array $project
     *   Associative array of information about a project as created by
     *   \Drupal\update\UpdateManager::getProjects(), including keys such as
     *   'name' (short name), and the 'info' array with data from a .info.yml
     *   file for the project.
     *
     * @see \Drupal\update\UpdateManager::getProjects()
     * @see update_get_available()
     * @see \Drupal\update\UpdateManager::refreshUpdateData()
     * @see \Drupal\update\UpdateProcessor::fetchData()
     * @see \Drupal\update\UpdateProcessor::processFetchTask()
     */
    public function createFetchTask($project);
    
    /**
     * Processes a task to fetch available update data for a single project.
     *
     * Once the release history XML data is downloaded, it is parsed and saved in
     * an entry just for that project.
     *
     * @param array $project
     *   Associative array of information about the project to fetch data for.
     *
     * @return bool
     *   TRUE if we fetched parsable XML, otherwise FALSE.
     */
    public function processFetchTask($project);
    
    /**
     * Retrieves the number of items in the update fetch queue.
     *
     * @return int
     *   An integer estimate of the number of items in the queue.
     *
     * @see \Drupal\Core\Queue\QueueInterface::numberOfItems()
     */
    public function numberOfQueueItems();
    
    /**
     * Deletes a finished item from the update fetch queue.
     *
     * @param object $item
     *   The item returned by \Drupal\Core\Queue\QueueInterface::claimItem().
     *
     * @see \Drupal\Core\Queue\QueueInterface::deleteItem()
     */
    public function deleteQueueItem($item);

}