Piwik\Tracker\Visit::getVisitorIdcookie PHP Method

    protected function getVisitorIdcookie()
    {
        $isKnown = $this->request->getMetadata('CoreHome', 'isVisitorKnown');
        if ($isKnown) {
            return $this->visitProperties->getProperty('idvisitor');
        }
        // If the visitor had a first party ID cookie, then we use this value
        $idVisitor = $this->visitProperties->getProperty('idvisitor');
        if (!empty($idVisitor) && Tracker::LENGTH_BINARY_ID == strlen($this->visitProperties->getProperty('idvisitor'))) {
            return $this->visitProperties->getProperty('idvisitor');
        }
        return Common::hex2bin($this->generateUniqueVisitorId());
    }