content_entity_base-8.x-1.x-dev/src/Entity/Storage/ContentEntityBaseStorage.php

<?php

namespace Drupal\content_entity_base\Entity\Storage;

use Drupal\Core\Entity\ContentEntityInterface;
use Drupal\Core\Entity\Sql\SqlContentEntityStorage;

class ContentEntityBaseStorage extends SqlContentEntityStorage implements RevisionableStorageInterface {

  /**
   * {@inheritdoc}
   */
  public function countDefaultLanguageRevisions(ContentEntityInterface $entity) {
    $entity_type = $entity->getEntityType();
    $count = $this->getQuery()
      ->allRevisions()
      ->condition($entity_type->getKey('id'), $entity->id())
      ->condition($entity_type->getKey('default_langcode'), 1)
      ->count()
      ->execute();
    return $count;
  }

  /**
   * {@inheritdoc}
   */
  public function revisionIds(ContentEntityInterface $entity) {
    // @todo Too bad that you cannot use an entity query here.
    $entity_type = $entity->getEntityType();
    $revision_table = $entity_type->getRevisionTable();
    $revision_field = $entity_type->getKey('revision');
    $id_field = $entity_type->getKey('id');
    $result = $this->database->select($revision_table)
      ->fields($revision_table, [$revision_field])
      ->condition($id_field, $entity->id())
      ->execute()
      ->fetchAllKeyed(0, 0);

    return array_values($result);
  }

}