Chris@18: <?php
Chris@18: 
Chris@18: namespace Drupal\jsonapi\Revisions;
Chris@18: 
Chris@18: use Drupal\Core\Entity\EntityInterface;
Chris@18: use Drupal\Core\Entity\EntityTypeManagerInterface;
Chris@18: 
Chris@18: /**
Chris@18:  * Base implementation for version negotiators.
Chris@18:  *
Chris@18:  * @internal JSON:API maintains no PHP API since its API is the HTTP API. This
Chris@18:  *   class may change at any time and this will break any dependencies on it.
Chris@18:  *
Chris@18:  * @see https://www.drupal.org/project/jsonapi/issues/3032787
Chris@18:  * @see jsonapi.api.php
Chris@18:  */
Chris@18: abstract class NegotiatorBase implements VersionNegotiatorInterface {
Chris@18: 
Chris@18:   /**
Chris@18:    * The entity type manager to load the revision.
Chris@18:    *
Chris@18:    * @var \Drupal\Core\Entity\EntityTypeManagerInterface
Chris@18:    */
Chris@18:   protected $entityTypeManager;
Chris@18: 
Chris@18:   /**
Chris@18:    * Constructs a version negotiator instance.
Chris@18:    *
Chris@18:    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
Chris@18:    *   The entity type manager.
Chris@18:    */
Chris@18:   public function __construct(EntityTypeManagerInterface $entity_type_manager) {
Chris@18:     $this->entityTypeManager = $entity_type_manager;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Gets the revision ID.
Chris@18:    *
Chris@18:    * @param \Drupal\Core\Entity\EntityInterface $entity
Chris@18:    *   The entity.
Chris@18:    * @param string $version_argument
Chris@18:    *   A value used to derive a revision ID for the given entity.
Chris@18:    *
Chris@18:    * @return int
Chris@18:    *   The revision ID.
Chris@18:    *
Chris@18:    * @throws \Drupal\jsonapi\Revisions\VersionNotFoundException
Chris@18:    *   When the revision does not exist.
Chris@18:    * @throws \Drupal\jsonapi\Revisions\InvalidVersionIdentifierException
Chris@18:    *   When the revision ID is not valid.
Chris@18:    */
Chris@18:   abstract protected function getRevisionId(EntityInterface $entity, $version_argument);
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    */
Chris@18:   public function getRevision(EntityInterface $entity, $version_argument) {
Chris@18:     return $this->loadRevision($entity, $this->getRevisionId($entity, $version_argument));
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Loads an entity revision.
Chris@18:    *
Chris@18:    * @param \Drupal\Core\Entity\EntityInterface $entity
Chris@18:    *   The entity for which to load a revision.
Chris@18:    * @param int $revision_id
Chris@18:    *   The revision ID to be loaded.
Chris@18:    *
Chris@18:    * @return \Drupal\Core\Entity\EntityInterface|null
Chris@18:    *   The revision or NULL if the revision does not exists.
Chris@18:    *
Chris@18:    * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
Chris@18:    *   Thrown if the entity type doesn't exist.
Chris@18:    * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
Chris@18:    *   Thrown if the storage handler couldn't be loaded.
Chris@18:    */
Chris@18:   protected function loadRevision(EntityInterface $entity, $revision_id) {
Chris@18:     $storage = $this->entityTypeManager->getStorage($entity->getEntityTypeId());
Chris@18:     $revision = static::ensureVersionExists($storage->loadRevision($revision_id));
Chris@18:     if ($revision->id() !== $entity->id()) {
Chris@18:       throw new VersionNotFoundException(sprintf('The requested resource does not have a version with ID %s.', $revision_id));
Chris@18:     }
Chris@18:     return $revision;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Helper method that ensures that a version exists.
Chris@18:    *
Chris@18:    * @param int|\Drupal\Core\Entity\EntityInterface $revision
Chris@18:    *   A revision ID, or NULL if one was not found.
Chris@18:    *
Chris@18:    * @return int|\Drupal\Core\Entity\EntityInterface
Chris@18:    *   A revision or revision ID, if one was found.
Chris@18:    *
Chris@18:    * @throws \Drupal\jsonapi\Revisions\VersionNotFoundException
Chris@18:    *   Thrown if the given value is NULL, meaning the requested version was not
Chris@18:    *   found.
Chris@18:    */
Chris@18:   protected static function ensureVersionExists($revision) {
Chris@18:     if (is_null($revision)) {
Chris@18:       throw new VersionNotFoundException();
Chris@18:     }
Chris@18:     return $revision;
Chris@18:   }
Chris@18: 
Chris@18: }