interface RevisionableStorageInterface

interface RevisionableStorageInterface extends EntityStorageInterface {
    
    /**
     * Creates a new revision starting off from the specified entity object.
     *
     * @param \Drupal\Core\Entity\RevisionableInterface $entity
     *   The revisionable entity object being modified.
     * @param bool $default
     *   (optional) Whether the new revision should be marked as default. Defaults
     *   to TRUE.
     *
     * @return \Drupal\Core\Entity\RevisionableInterface
     *   A new entity revision object.
     */
    public function createRevision(RevisionableInterface $entity, $default = TRUE);
    
    /**
     * Loads a specific entity revision.
     *
     * @param int $revision_id
     *   The revision ID.
     *
     * @return \Drupal\Core\Entity\RevisionableInterface|null
     *   The specified entity revision or NULL if not found.
     */
    public function loadRevision($revision_id);
    
    /**
     * Loads multiple entity revisions.
     *
     * @param array $revision_ids
     *   An array of revision IDs to load.
     *
     * @return \Drupal\Core\Entity\RevisionableInterface[]
     *   An array of entity revisions keyed by their revision ID, or an empty
     *   array if none found.
     */
    public function loadMultipleRevisions(array $revision_ids);
    
    /**
     * Deletes a specific entity revision.
     *
     * A revision can only be deleted if it's not the currently active one.
     *
     * @param int $revision_id
     *   The revision ID.
     */
    public function deleteRevision($revision_id);
    
    /**
     * Returns the latest revision identifier for an entity.
     *
     * @param int|string $entity_id
     *   The entity identifier.
     *
     * @return int|string|null
     *   The latest revision identifier or NULL if no revision could be found.
     */
    public function getLatestRevisionId($entity_id);

}