file_checker.module

<?php

/**
 * @file
 * File Checker hooks and callbacks.
 */

use Drupal\Core\Field\BaseFieldDefinition;
use Drupal\file\FileInterface;
use Drupal\Core\Entity\EntityTypeInterface;

/**
 * Implements hook_entity_base_field_info().
 *
 * Adds a 'missing' basefield to the core file entity.
 */
function file_checker_entity_base_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
  if ($entity_type->id() == 'file') {
    $fields = array();
    $fields['missing'] = BaseFieldDefinition::create('boolean')
      ->setLabel(t('Missing'))
      ->setDescription(t('Whether the file can be found at the uri.'));
    // ->setRevisionable(TRUE);
    return $fields;
  }
}

/**
 * The callback function for an Ultimate Cron job that starts file checking.
 */
function file_checker_start($job) {
  \Drupal::service('file_checker.bulk_file_checking')->start();
}

/**
 * The callback for an Ultimate Cron job that checks fies for up to 50 seconds.
 */
function file_checker_execute50($job) {
  \Drupal::service('file_checker.bulk_file_checking')->executeInBackground(50);
}

/**
 * The callback for the batch API launch from UI.
 */
function file_checker_execute_in_ui(&$context) {
  \Drupal::service('file_checker.bulk_file_checking')->executeInUI(10, $context);
}

/**
 * Implements hook_ENTITY_TYPE_insert() for file.
 *
 * Check files when recorded location changes, if configured to do so.
 * We use update/insert not presave out of concern that the file might not have
 * been moved into its uri location at the time of presave.
 */
function file_checker_file_insert(FileInterface $file) {
  \Drupal::service('file_checker.single_file_checking')->checkIfChanged($file);
}

/**
 * Implements hook_ENTITY_TYPE_update() for file.
 *
 * Check files when recorded location changes, if configured to do so.
 * We use update/insert not presave out of concern that the file might not
 * have been moved into its uri location at the time of presave.
 */
function file_checker_file_update(FileInterface $file) {
  \Drupal::service('file_checker.single_file_checking')->checkIfChanged($file);
}