Piwik\Segment::initializeSegment PHP Method

    protected function initializeSegment($string, $idSites)
    {
        // As a preventive measure, we restrict the filter size to a safe limit
        $string = substr($string, 0, self::SEGMENT_TRUNCATE_LIMIT);
        $this->string = $string;
        $this->idSites = $idSites;
        $segment = new SegmentExpression($string);
        $this->segmentExpression = $segment;
        // parse segments
        $expressions = $segment->parseSubExpressions();
        $expressions = $this->getExpressionsWithUnionsResolved($expressions);
        // convert segments name to sql segment
        // check that user is allowed to view this segment
        // and apply a filter to the value to match if necessary (to map DB fields format)
        $cleanedExpressions = array();
        foreach ($expressions as $expression) {
            $operand = $expression[SegmentExpression::INDEX_OPERAND];
            $cleanedExpression = $this->getCleanedExpression($operand);
            $expression[SegmentExpression::INDEX_OPERAND] = $cleanedExpression;
            $cleanedExpressions[] = $expression;
        }
        $segment->setSubExpressionsAfterCleanup($cleanedExpressions);
    }