class EntityTypeInfo

class EntityTypeInfo implements ContainerInjectionInterface {
    use StringTranslationTrait;
    
    /**
     * The current user.
     *
     * @var \Drupal\Core\Session\AccountInterface
     */
    protected $currentUser;
    
    /**
     * EntityTypeInfo constructor.
     *
     * @param \Drupal\Core\Session\AccountInterface $current_user
     *   Current user.
     */
    public function __construct(AccountInterface $current_user) {
        $this->currentUser = $current_user;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('current_user'));
    }
    
    /**
     * Adds devel links to appropriate entity types.
     *
     * This is an alter hook bridge.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface[] $entity_types
     *   The master entity type list to alter.
     *
     * @see hook_entity_type_alter()
     */
    public function entityTypeAlter(array &$entity_types) {
        foreach ($entity_types as $entity_type_id => $entity_type) {
            if (($entity_type->getFormClass('default') || $entity_type->getFormClass('edit')) && $entity_type->hasLinkTemplate('edit-form')) {
                $entity_type->setLinkTemplate('devel-load', "/devel/{$entity_type_id}/{{$entity_type_id}}");
            }
            if ($entity_type->hasViewBuilderClass() && $entity_type->hasLinkTemplate('canonical')) {
                $entity_type->setLinkTemplate('devel-render', "/devel/{$entity_type_id}/{{$entity_type_id}}/render");
            }
            if ($entity_type->hasLinkTemplate('devel-render') || $entity_type->hasLinkTemplate('devel-load')) {
                $entity_type->setLinkTemplate('devel-definition', "/devel/{$entity_type_id}/{{$entity_type_id}}/definition");
            }
        }
    }
    
    /**
     * Adds devel operations on entity that supports it.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity on which to define an operation.
     *
     * @return array
     *   An array of operation definitions.
     *
     * @see hook_entity_operation()
     */
    public function entityOperation(EntityInterface $entity) {
        $operations = [];
        if ($this->currentUser
            ->hasPermission('access devel information')) {
            if ($entity->hasLinkTemplate('devel-load')) {
                $operations['devel'] = [
                    'title' => $this->t('Devel'),
                    'weight' => 100,
                    'url' => $entity->toUrl('devel-load'),
                ];
            }
            elseif ($entity->hasLinkTemplate('devel-render')) {
                $operations['devel'] = [
                    'title' => $this->t('Devel'),
                    'weight' => 100,
                    'url' => $entity->toUrl('devel-render'),
                ];
            }
        }
        return $operations;
    }

}