GeneralizedSql.php

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<?php
namespace Wikimedia\Rdbms;
 
class GeneralizedSql {
    private $rawSql;
    private $prefix;
 
    private $genericSql;
 
    public function __construct( $rawSql, $prefix ) {
        $this->rawSql = $rawSql;
        $this->prefix = $prefix;
    }
 
    private static function generalizeSQL( $sql ) {
        # This does the same as the regexp below would do, but in such a way
        # as to avoid crashing php on some large strings.
        # $sql = preg_replace( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql );
 
        $sql = str_replace( "\\\\", '', $sql );
        $sql = str_replace( "\\'", '', $sql );
        $sql = str_replace( "\\\"", '', $sql );
        $sql = preg_replace( "/'.*'/s", "'X'", $sql );
        $sql = preg_replace( '/".*"/s', "'X'", $sql );
 
        # All newlines, tabs, etc replaced by single space
        $sql = preg_replace( '/\s+/', ' ', $sql );
 
        # All numbers => N,
        # except the ones surrounded by characters, e.g. l10n
        $sql = preg_replace( '/-?\d+(,-?\d+)+/s', 'N,...,N', $sql );
        $sql = preg_replace( '/(?<![a-zA-Z])-?\d+(?![a-zA-Z])/s', 'N', $sql );
 
        return $sql;
    }
 
    public function stringify() {
        if ( $this->genericSql !== null ) {
            return $this->genericSql;
        }
 
        $this->genericSql = $this->prefix .
            substr( self::generalizeSQL( $this->rawSql ), 0, 255 );
 
        return $this->genericSql;
    }
 
    public function getRawSql() {
        return $this->rawSql;
    }
}