Chris@18: <?php
Chris@18: 
Chris@18: namespace Drupal\user;
Chris@18: 
Chris@18: use Drupal\Core\Entity\EntityTypeInterface;
Chris@18: use Drupal\Core\Entity\Exception\UnsupportedEntityTypeDefinitionException;
Chris@18: use Drupal\Core\Field\BaseFieldDefinition;
Chris@18: use Drupal\Core\StringTranslation\TranslatableMarkup;
Chris@18: 
Chris@18: /**
Chris@18:  * Provides a trait for entities that have an owner.
Chris@18:  */
Chris@18: trait EntityOwnerTrait {
Chris@18: 
Chris@18:   /**
Chris@18:    * Returns an array of base field definitions for entity owners.
Chris@18:    *
Chris@18:    * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
Chris@18:    *   The entity type to add the owner field to.
Chris@18:    *
Chris@18:    * @return \Drupal\Core\Field\BaseFieldDefinition[]
Chris@18:    *   An array of base field definitions.
Chris@18:    *
Chris@18:    * @throws \Drupal\Core\Entity\Exception\UnsupportedEntityTypeDefinitionException
Chris@18:    *   Thrown when the entity type does not implement EntityOwnerInterface or
Chris@18:    *   if it does not have an "owner" entity key.
Chris@18:    */
Chris@18:   public static function ownerBaseFieldDefinitions(EntityTypeInterface $entity_type) {
Chris@18:     if (!is_subclass_of($entity_type->getClass(), EntityOwnerInterface::class)) {
Chris@18:       throw new UnsupportedEntityTypeDefinitionException('The entity type ' . $entity_type->id() . ' does not implement \Drupal\user\EntityOwnerInterface.');
Chris@18:     }
Chris@18:     if (!$entity_type->hasKey('owner')) {
Chris@18:       throw new UnsupportedEntityTypeDefinitionException('The entity type ' . $entity_type->id() . ' does not have an "owner" entity key.');
Chris@18:     }
Chris@18: 
Chris@18:     return [
Chris@18:       $entity_type->getKey('owner') => BaseFieldDefinition::create('entity_reference')
Chris@18:         ->setLabel(new TranslatableMarkup('User ID'))
Chris@18:         ->setSetting('target_type', 'user')
Chris@18:         ->setTranslatable($entity_type->isTranslatable())
Chris@18:         ->setDefaultValueCallback(static::class . '::getDefaultEntityOwner'),
Chris@18:     ];
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    */
Chris@18:   public function getOwnerId() {
Chris@18:     return $this->getEntityKey('owner');
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    */
Chris@18:   public function setOwnerId($uid) {
Chris@18:     $key = $this->getEntityType()->getKey('owner');
Chris@18:     $this->set($key, $uid);
Chris@18: 
Chris@18:     return $this;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    */
Chris@18:   public function getOwner() {
Chris@18:     $key = $this->getEntityType()->getKey('owner');
Chris@18:     return $this->get($key)->entity;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    */
Chris@18:   public function setOwner(UserInterface $account) {
Chris@18:     $key = $this->getEntityType()->getKey('owner');
Chris@18:     $this->set($key, $account);
Chris@18: 
Chris@18:     return $this;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Default value callback for 'owner' base field.
Chris@18:    *
Chris@18:    * @return mixed
Chris@18:    *   A default value for the owner field.
Chris@18:    */
Chris@18:   public static function getDefaultEntityOwner() {
Chris@18:     return \Drupal::currentUser()->id();
Chris@18:   }
Chris@18: 
Chris@18: }