backupPrefetch.inc

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<?php
class BaseDump {
    var $reader = null;
    var $atEnd = false;
    var $atPageEnd = false;
    var $lastPage = 0;
    var $lastRev = 0;
    var $infiles = null;

    function BaseDump( $infile ) {
        $this->infiles = explode( ';', $infile );
        $this->reader = new XMLReader();
        $infile = array_shift( $this->infiles );
        if ( defined( 'LIBXML_PARSEHUGE' ) ) {
            $this->reader->open( $infile, null, LIBXML_PARSEHUGE );
        }
        else {
            $this->reader->open( $infile );
        }
    }

    function prefetch( $page, $rev ) {
        $page = intval( $page );
        $rev = intval( $rev );
        while ( $this->lastPage < $page && !$this->atEnd ) {
            $this->debug( "BaseDump::prefetch at page $this->lastPage, looking for $page" );
            $this->nextPage();
        }
        if ( $this->lastPage > $page || $this->atEnd ) {
            $this->debug( "BaseDump::prefetch already past page $page looking for rev $rev  [$this->lastPage, $this->lastRev]" );
            return null;
        }
        while ( $this->lastRev < $rev && !$this->atEnd && !$this->atPageEnd ) {
            $this->debug( "BaseDump::prefetch at page $this->lastPage, rev $this->lastRev, looking for $page, $rev" );
            $this->nextRev();
        }
        if ( $this->lastRev == $rev && !$this->atEnd ) {
            $this->debug( "BaseDump::prefetch hit on $page, $rev [$this->lastPage, $this->lastRev]" );
            return $this->nextText();
        } else {
            $this->debug( "BaseDump::prefetch already past rev $rev on page $page  [$this->lastPage, $this->lastRev]" );
            return null;
        }
    }

    function debug( $str ) {
        wfDebug( $str . "\n" );
        // global $dumper;
        // $dumper->progress( $str );
    }

    function nextPage() {
        if ( $this->skipTo( 'page', 'mediawiki' ) ) {
            if ( $this->skipTo( 'id' ) ) {
                $this->lastPage = intval( $this->nodeContents() );
                $this->lastRev = 0;
                $this->atPageEnd = false;
            }
        } else {
            $this->close();
            if ( count( $this->infiles ) ) {
                $infile = array_shift( $this->infiles );
                $this->reader->open( $infile );
                $this->atEnd = false;
            }
        }
    }

    function nextRev() {
        if ( $this->skipTo( 'revision' ) ) {
            if ( $this->skipTo( 'id' ) ) {
                $this->lastRev = intval( $this->nodeContents() );
            }
        } else {
            $this->atPageEnd = true;
        }
    }

    function nextText() {
        $this->skipTo( 'text' );
        return strval( $this->nodeContents() );
    }

    function skipTo( $name, $parent = 'page' ) {
        if ( $this->atEnd ) {
            return false;
        }
        while ( $this->reader->read() ) {
            if ( $this->reader->nodeType == XMLReader::ELEMENT &&
                $this->reader->name == $name ) {
                return true;
            }
            if ( $this->reader->nodeType == XMLReader::END_ELEMENT &&
                $this->reader->name == $parent ) {
                $this->debug( "BaseDump::skipTo found </$parent> searching for <$name>" );
                return false;
            }
        }
        return $this->close();
    }

    function nodeContents() {
        if ( $this->atEnd ) {
            return null;
        }
        if ( $this->reader->isEmptyElement ) {
            return "";
        }
        $buffer = "";
        while ( $this->reader->read() ) {
            switch ( $this->reader->nodeType ) {
            case XMLReader::TEXT:
//          case XMLReader::WHITESPACE:
            case XMLReader::SIGNIFICANT_WHITESPACE:
                $buffer .= $this->reader->value;
                break;
            case XMLReader::END_ELEMENT:
                return $buffer;
            }
        }
        return $this->close();
    }

    function close() {
        $this->reader->close();
        $this->atEnd = true;
        return null;
    }
}