EntityStorageBase::doPreSave

protected EntityStorageBase::doPreSave(EntityInterface $entity)

protected function doPreSave(EntityInterface $entity) {
  $id = $entity->id();

  // Track the original ID.
  if ($entity->getOriginalId() !== NULL) {
    $id = $entity->getOriginalId();
  }

  // Track if this entity exists already.
  $id_exists = $this->has($id, $entity);

  // A new entity should not already exist.
  if ($id_exists && $entity->isNew()) {
    throw new EntityStorageException("'{$this->entityTypeId}' entity with ID '$id' already exists.");
  }

  // Load the original entity, if any.
  if ($id_exists && !isset($entity->original)) {
    $entity->original = $this->loadUnchanged($id);
  }

  // Allow code to run before saving.
  $entity->preSave($this);
  $this->invokeHook('presave', $entity);

  return $id;
}