Sharing::getExisting

static function getExisting($userId, BaseObject $object)
{
	$userId = (int)$userId;
	$sharings = static::getModelList(array(
		'filter' => array(
			'REAL_OBJECT_ID' => $object->getRealObjectId(),
			'=TO_ENTITY' => self::CODE_USER . $userId,
			'@STATUS' => array(
				SharingTable::STATUS_IS_UNREPLIED,
				SharingTable::STATUS_IS_APPROVED,
			),
		),
		'limit' => 1,
	));

	return array_shift($sharings)?: null;
}