entity_value_inheritance-1.3.0/src/EventSubscriber/DisabledFieldSubscriber.php

<?php

namespace Drupal\entity_value_inheritance\EventSubscriber;

use Drupal\Core\Render\Element;
use Drupal\entity_value_inheritance\Event\InheritanceAlterFieldEvent;
use Drupal\entity_value_inheritance\Event\InheritanceEvents;

/**
 * Event Subscriber used for Disabling fields.
 */
class DisabledFieldSubscriber extends EventSubscriberBase {

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents(): array {
    $events = [];
    $events[InheritanceEvents::ALTER_FIELD][] = ['disableField', 1000];
    return $events;
  }

  /**
   * Disable the field.
   *
   * Event to disable the field if the configuration is set to disabled and
   * show the message.
   */
  public function disableField(InheritanceAlterFieldEvent $event) {
    $inheritance = $event->getInheritance();
    if (
      $inheritance->getStrategy() === 'disable' &&
      !($event->getEntity()->get($inheritance->getDestinationReferenceField())->isEmpty())
    ) {
      $element = $event->getElement();
      $this->modifyField($element);
      $event->setElement($element);

      $message = $inheritance->getSetting('message');
      $event->setMessage($message);
    }
  }

  /**
   * Add disable attribute to all children.
   *
   * @param array &$element
   *   Element to loop through.
   */
  protected function modifyField(array &$element): void {
    $children = Element::getVisibleChildren($element);
    $element['#disabled'] = TRUE;
    // If there are children then recurse the function.
    if (count($children) > 0) {
      foreach ($children as $child) {
        $this->modifyField($element[$child]);
      }
    }
  }

}