PathFieldItemList.php

<?php

namespace Drupal\path\Plugin\Field\FieldType;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Field\FieldItemList;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\TypedData\ComputedItemListTrait;

/**
 * Represents a configurable entity path field.
 */
class PathFieldItemList extends FieldItemList {
  use ComputedItemListTrait;
  
  /**
   * {@inheritdoc}
   */
  protected function computeValue() {
    // Default the langcode to the current language if this is a new entity or
    // there is no alias for an existent entity.
    // @todo Set the langcode to not specified for untranslatable fields
    //   in https://www.drupal.org/node/2689459.
    $value = [
      'langcode' => $this->getLangcode(),
    ];
    $entity = $this->getEntity();
    if (!$entity->isNew()) {
      /** @var \Drupal\path_alias\AliasRepositoryInterface $path_alias_repository */
      $path_alias_repository = \Drupal::service('path_alias.repository');
      if ($path_alias = $path_alias_repository->lookupBySystemPath('/' . $entity->toUrl()
        ->getInternalPath(), $this->getLangcode())) {
        $value = [
          'alias' => $path_alias['alias'],
          'pid' => $path_alias['id'],
          'langcode' => $path_alias['langcode'],
        ];
      }
    }
    $this->list[0] = $this->createItem(0, $value);
  }
  
  /**
   * {@inheritdoc}
   */
  public function defaultAccess($operation = 'view', ?AccountInterface $account = NULL) {
    if ($operation == 'view') {
      return AccessResult::allowed();
    }
    return AccessResult::allowedIfHasPermissions($account, [
      'create url aliases',
      'administer url aliases',
    ], 'OR')->cachePerPermissions();
  }
  
  /**
   * {@inheritdoc}
   */
  public function delete() {
    // Delete all aliases associated with this entity in the current language.
    $entity = $this->getEntity();
    $path_alias_storage = \Drupal::entityTypeManager()->getStorage('path_alias');
    $entities = $path_alias_storage->loadByProperties([
      'path' => '/' . $entity->toUrl()
        ->getInternalPath(),
      'langcode' => $entity->language()
        ->getId(),
    ]);
    $path_alias_storage->delete($entities);
  }

}