MySQLMasterPos.php

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<?php
 
namespace Wikimedia\Rdbms;
 
use InvalidArgumentException;
 
class MySQLMasterPos implements DBMasterPos {
    public $file;
    public $pos;
    public $gtids = [];
    public $asOfTime = 0.0;
 
    function __construct( $file, $pos, $gtid = '' ) {
        $this->file = $file;
        $this->pos = $pos;
        $this->gtids = array_map( 'trim', explode( ',', $gtid ) );
        $this->asOfTime = microtime( true );
    }
 
    function __toString() {
        return "{$this->file}/{$this->pos}";
    }
 
    function asOfTime() {
        return $this->asOfTime;
    }
 
    function hasReached( DBMasterPos $pos ) {
        if ( !( $pos instanceof self ) ) {
            throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
        }
 
        // Prefer GTID comparisons, which work with multi-tier replication
        $thisPosByDomain = $this->getGtidCoordinates();
        $thatPosByDomain = $pos->getGtidCoordinates();
        if ( $thisPosByDomain && $thatPosByDomain ) {
            $reached = true;
            // Check that this has positions GTE all of those in $pos for all domains in $pos
            foreach ( $thatPosByDomain as $domain => $thatPos ) {
                $thisPos = isset( $thisPosByDomain[$domain] ) ? $thisPosByDomain[$domain] : -1;
                $reached = $reached && ( $thatPos <= $thisPos );
            }
 
            return $reached;
        }
 
        // Fallback to the binlog file comparisons
        $thisBinPos = $this->getBinlogCoordinates();
        $thatBinPos = $pos->getBinlogCoordinates();
        if ( $thisBinPos && $thatBinPos && $thisBinPos['binlog'] === $thatBinPos['binlog'] ) {
            return ( $thisBinPos['pos'] >= $thatBinPos['pos'] );
        }
 
        // Comparing totally different binlogs does not make sense
        return false;
    }
 
    function channelsMatch( DBMasterPos $pos ) {
        if ( !( $pos instanceof self ) ) {
            throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
        }
 
        // Prefer GTID comparisons, which work with multi-tier replication
        $thisPosDomains = array_keys( $this->getGtidCoordinates() );
        $thatPosDomains = array_keys( $pos->getGtidCoordinates() );
        if ( $thisPosDomains && $thatPosDomains ) {
            // Check that this has GTIDs for all domains in $pos
            return !array_diff( $thatPosDomains, $thisPosDomains );
        }
 
        // Fallback to the binlog file comparisons
        $thisBinPos = $this->getBinlogCoordinates();
        $thatBinPos = $pos->getBinlogCoordinates();
 
        return ( $thisBinPos && $thatBinPos && $thisBinPos['binlog'] === $thatBinPos['binlog'] );
    }
 
    protected function getGtidCoordinates() {
        $gtidInfos = [];
        foreach ( $this->gtids as $gtid ) {
            $m = [];
            // MariaDB style: <domain>-<server id>-<sequence number>
            if ( preg_match( '!^(\d+)-\d+-(\d+)$!', $gtid, $m ) ) {
                $gtidInfos[(int)$m[1]] = (int)$m[2];
                // MySQL style: <UUID domain>:<sequence number>
            } elseif ( preg_match( '!^(\w{8}-\w{4}-\w{4}-\w{4}-\w{12}):(\d+)$!', $gtid, $m ) ) {
                $gtidInfos[$m[1]] = (int)$m[2];
            } else {
                $gtidInfos = [];
                break; // unrecognized GTID
            }
 
        }
 
        return $gtidInfos;
    }
 
    protected function getBinlogCoordinates() {
        $m = [];
        if ( preg_match( '!^(.+)\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
            return [ 'binlog' => $m[1], 'pos' => [ (int)$m[2], (int)$m[3] ] ];
        }
 
        return false;
    }
}