CheckAccess::onBeforeAction

public function onBeforeAction(Event $event)
{
	foreach($this->action->getArguments() as $argument)
	{
		if($argument instanceof Document)
		{
			$userId = $this->action->getController()->getCurrentUser()->getId();
			if($userId > 0)
			{
				$argument->setUserId($userId);
			}
			if(!$argument->hasAccess())
			{
				$this->errorCollection[] = new Error(
					'Access denied', BitrixDocumentGeneratorControllerDocument::ERROR_ACCESS_DENIED
				);

				return new EventResult(EventResult::ERROR, null, null, $this);
			}
		}
	}

	return null;
}