XpathParser.php

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<?php
 
namespace Depage\XmlDb;
 
use Depage\XmlDb\Exceptions\XmlDbException;

class XpathParser
{
    public function parseXpathElements(string $xpath): array
    {
        $pName       = '(?:([^\/\‍[\‍]]*):)?([^\/\‍[\‍]]+)';
        $pCondition = '(?:\‍[(.*?)\‍])?';
        preg_match_all("/(\/+)$pName$pCondition/", $xpath, $raw, PREG_SET_ORDER);
 
        $elements = [];
        foreach ($raw as $match) {
            $elements[] = new XpathElement(
                $match[1] ?? '',    // divider
                $match[2] ?? '',    // namespace
                $match[3] ?? '',    // name
                $match[4] ?? ''     // condition
            );
        }
        return $elements;
    }

    public function parsePosition($condition): array|false
    {
        $positionArray = [];
        $matches = [];
        $pOperator = '(=|!=|<|>|<=|>=)';
        $pPosition = '([0-9]+)';
 
        if (preg_match("/^\s*(?:(?:position\‍(\‍))\s*$pOperator)?\s*$pPosition\s*$/", $condition, $matches)) {
            $positionArray[] = ($matches[1] == '') ? '=' : $matches[1];
            $positionArray[] = $matches[2];
            return $positionArray;
        }
        return false;
    }

    public function parseAttributes($condition): false|array
    {
        $condArray = false;
        $tempCondition = $this->removeLiteralStrings($condition, $strings);
 
        if (preg_match('/^[\w\d@=: -<>\*]*$/', $tempCondition)) {
            $condArray = $this->getConditionAttributes($tempCondition, $strings);
        }
        return $condArray;
    }

    public function translateName($ns, $name): string
    {
        $colon = (strlen($ns) && strlen($name)) ? ':' : '';
        return str_replace('*', '%', "$ns$colon$name");
    }

    public function getConditionOperator($ns, $name): string
    {
        if (str_contains($ns, "*") || str_contains($name, "*")) {
            return 'LIKE';
        } else {
            return '=';
        }
    }

    public function getConditionAttributes($conditionString, $strings): array
    {
        $conditionArray = [];
        $pAttr     = '@(\w[\w\d:]*)';
        $pOperator = '(=|!=|<|>|<=|>=)';
        $pBool     = '([^@\s]+)';
        $pString   = '\$(\d*)';
 
        $matched = preg_match_all("/$pBool?\s*$pAttr\s*(?:$pOperator\s*$pString)?/", $conditionString, $conditions, PREG_SET_ORDER);
 
        $first = true;
        foreach ($conditions as $condition) {
            $bool = $condition[1] ? strtolower($condition[1]) : null;
            if ($first && $bool) {
                throw new XmlDbException('Invalid XPath syntax');
            }
            if (!in_array($bool, ['and', 'or', null])) {
                throw new XmlDbException('Invalid XPath syntax');
            }
 
            if ($first) {
                $first = false;
            }
 
            $conditionArray[] = [
                $condition[2],
                $condition[3] ?? null,
                (isset($condition[4]) && $condition[4] != '') ? $strings[$condition[4]] : null,
                $bool,
            ];
        }
        return $conditionArray;
    }

    protected function removeLiteralStrings($text, &$strings): string
    {
        $n     = 0;
        $newText = '';
        $strings = [];
 
        $p = "/([^\"']*)|(?:\"([^\"]*)\"|'([^']*)')/";
        preg_match_all($p, $text, $parts);
 
        for ($i = 0; $i < count($parts[0]); $i++) {
            if ($parts[1][$i] == '' && ($parts[2][$i] != '' || $parts[3][$i] != '')) {
                $strings[$n] = $parts[2][$i] . $parts[3][$i];
                $newText .= "\$$n";
                $n++;
            } else {
                $newText .= $parts[1][$i];
            }
        }
        return $newText;
    }

    public function cleanOperator($operator): string
    {
        $operator = strtolower(trim($operator));
        $cleaned = '';
        $operators = ['=', '!=', '<=', '>=', '<', '>', 'and', 'or'];
 
        if (in_array($operator, $operators)) {
            $cleaned = $operator;
        } else {
            throw new XmlDbException("Invalid XPath operator \"$operator\"");
        }
        return $cleaned;
    }
}
 
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