EntityCopier::copy

public function copy(ContainerCollection $containerCollection)
{
	$this->result->setData([]);

	$result = [];
	foreach ($containerCollection as $container)
	{
		$entityId = $this->getEntityIdToCopy($container);
		if (!$entityId)
		{
			continue;
		}

		$fields = $this->getFields($container, $entityId);

		if (empty($fields))
		{
			$result = $this->addToResultByName($result, [$entityId => false], $this->implementerName);
		}
		else
		{
			$dictionary = $this->getDictionary($container, $fields);

			$fields = $this->prepareFieldsToCopy($container, $fields);

			$copiedEntityId = $this->addEntity($container, $fields);
			if (!$copiedEntityId)
			{
				$result = $this->addToResultByName($result, [$entityId => false], $this->implementerName);
				$this->result->addErrors($this->implementer->getErrors());
				continue;
			}

			$copyChildrenResult = $this->copyChildren($container, $entityId, $copiedEntityId);
			if ($copyChildrenResult->getErrors())
			{
				$this->result->addErrors($copyChildrenResult->getErrors());
			}
			$result = $this->addToResult($result, $copyChildrenResult->getData());

			$result = $this->addToResultByName($result, [$entityId => $copiedEntityId], $this->implementerName);

			$this->setCopiedEntityId($container, $copiedEntityId);

			$this->setDictionary($container, $dictionary);
		}
	}

	$this->startCopyEntities($containerCollection);

	$result = $this->addToResult($result, $this->result->getData());

	$this->result->setData($result);

	return $this->result;
}