Log dump cleanup for WikiExporter::STREAM

[mediawiki.git] / includes / Export.php

<?php
# Copyright (C) 2003, 2005, 2006 Brion Vibber <brion@pobox.com>
# http://www.mediawiki.org/
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
# http://www.gnu.org/copyleft/gpl.html

/**
 * @defgroup Dump Dump
 */

/**
 * @ingroup SpecialPage Dump
 */
class WikiExporter {
        var $list_authors = false ; # Return distinct author list (when not returning full history)
        var $author_list = "" ;

        var $dumpUploads = false;

        const FULL = 0;
        const CURRENT = 1;
        const LOGS = 2;

        const BUFFER = 0;
        const STREAM = 1;

        const TEXT = 0;
        const STUB = 1;

        /**
         * If using WikiExporter::STREAM to stream a large amount of data,
         * provide a database connection which is not managed by
         * LoadBalancer to read from: some history blob types will
         * make additional queries to pull source data while the
         * main query is still running.
         *
         * @param $db Database
         * @param $history Mixed: one of WikiExporter::FULL or WikiExporter::CURRENT,
         *                 or an associative array:
         *                   offset: non-inclusive offset at which to start the query
         *                   limit: maximum number of rows to return
         *                   dir: "asc" or "desc" timestamp order
         * @param $buffer Int: one of WikiExporter::BUFFER or WikiExporter::STREAM
         */
        function __construct( &$db, $history = WikiExporter::CURRENT,
                        $buffer = WikiExporter::BUFFER, $text = WikiExporter::TEXT ) {
                $this->db =& $db;
                $this->history = $history;
                $this->buffer  = $buffer;
                $this->writer  = new XmlDumpWriter();
                $this->sink    = new DumpOutput();
                $this->text    = $text;
        }

        /**
         * Set the DumpOutput or DumpFilter object which will receive
         * various row objects and XML output for filtering. Filters
         * can be chained or used as callbacks.
         *
         * @param $sink mixed
         */
        public function setOutputSink( &$sink ) {
                $this->sink =& $sink;
        }

        public function openStream() {
                $output = $this->writer->openStream();
                $this->sink->writeOpenStream( $output );
        }

        public function closeStream() {
                $output = $this->writer->closeStream();
                $this->sink->writeCloseStream( $output );
        }

        /**
         * Dumps a series of page and revision records for all pages
         * in the database, either including complete history or only
         * the most recent version.
         */
        public function allPages() {
                return $this->dumpFrom( '' );
        }

        /**
         * Dumps a series of page and revision records for those pages
         * in the database falling within the page_id range given.
         * @param $start Int: inclusive lower limit (this id is included)
         * @param $end   Int: Exclusive upper limit (this id is not included)
         *                   If 0, no upper limit.
         */
        public function pagesByRange( $start, $end ) {
                $condition = 'page_id >= ' . intval( $start );
                if( $end ) {
                        $condition .= ' AND page_id < ' . intval( $end );
                }
                return $this->dumpFrom( $condition );
        }

        /**
         * @param $title Title
         */
        public function pageByTitle( $title ) {
                return $this->dumpFrom(
                        'page_namespace=' . $title->getNamespace() .
                        ' AND page_title=' . $this->db->addQuotes( $title->getDBkey() ) );
        }

        public function pageByName( $name ) {
                $title = Title::newFromText( $name );
                if( is_null( $title ) ) {
                        return new WikiError( "Can't export invalid title" );
                } else {
                        return $this->pageByTitle( $title );
                }
        }

        public function pagesByName( $names ) {
                foreach( $names as $name ) {
                        $this->pageByName( $name );
                }
        }

        public function allLogs() {
                return $this->dumpFrom( '' );
        }

        public function logsByRange( $start, $end ) {
                $condition = 'log_id >= ' . intval( $start );
                if( $end ) {
                        $condition .= ' AND log_id < ' . intval( $end );
                }
                return $this->dumpFrom( $condition );
        }

        # Generates the distinct list of authors of an article
        # Not called by default (depends on $this->list_authors)
        # Can be set by Special:Export when not exporting whole history
        protected function do_list_authors( $page , $revision , $cond ) {
                $fname = "do_list_authors" ;
                wfProfileIn( $fname );
                $this->author_list = "<contributors>";
                //rev_deleted
                $nothidden = '(rev_deleted & '.Revision::DELETED_USER.') = 0';

                $sql = "SELECT DISTINCT rev_user_text,rev_user FROM {$page},{$revision} 
                WHERE page_id=rev_page AND $nothidden AND " . $cond ;
                $result = $this->db->query( $sql, $fname );
                $resultset = $this->db->resultObject( $result );
                while( $row = $resultset->fetchObject() ) {
                        $this->author_list .= "<contributor>" .
                                "<username>" .
                                htmlentities( $row->rev_user_text )  .
                                "</username>" .
                                "<id>" .
                                $row->rev_user .
                                "</id>" .
                                "</contributor>";
                }
                wfProfileOut( $fname );
                $this->author_list .= "</contributors>";
        }

        protected function dumpFrom( $cond = '' ) {
                $fname = 'WikiExporter::dumpFrom';
                wfProfileIn( $fname );
                
                # For logs dumps...
                if( $this->history & self::LOGS ) {
                        if( $this->buffer == WikiExporter::STREAM ) {
                                $prev = $this->db->bufferResults( false );
                        }
                        $where = array( 'user_id = log_user' );
                        # Hide private logs
                        $hideLogs = LogEventsList::getExcludeClause( $this->db );
                        if( $hideLogs ) $where[] = $hideLogs;
                        # Add on any caller specified conditions
                        if( $cond ) $where[] = $cond;
                        # Get logging table name for logging.* clause
                        $logging = $this->db->tableName('logging');
                        $result = $this->db->select( array('logging','user'), 
                                array( "{$logging}.*", 'user_name' ), // grab the user name
                                $where,
                                __METHOD__,
                                array( 'ORDER BY' => 'log_id', 'USE INDEX' => array('logging' => 'PRIMARY') )
                        );
                        $wrapper = $this->db->resultObject( $result );
                        if( $this->buffer == WikiExporter::STREAM ) {
                                $this->db->bufferResults( $prev );
                        }
                        $this->outputLogStream( $wrapper );
                # For page dumps...
                } else {
                        list($page,$revision,$text) = $this->db->tableNamesN('page','revision','text');

                        $order = 'ORDER BY page_id';
                        $limit = '';

                        if( $this->history == WikiExporter::FULL ) {
                                $join = 'page_id=rev_page';
                        } elseif( $this->history == WikiExporter::CURRENT ) {
                                if ( $this->list_authors && $cond != '' )  { // List authors, if so desired
                                        $this->do_list_authors ( $page , $revision , $cond );
                                }
                                $join = 'page_id=rev_page AND page_latest=rev_id';
                        } elseif ( is_array( $this->history ) ) {
                                $join = 'page_id=rev_page';
                                if ( $this->history['dir'] == 'asc' ) {
                                        $op = '>';
                                        $order .= ', rev_timestamp';
                                } else {
                                        $op = '<';
                                        $order .= ', rev_timestamp DESC';
                                }
                                if ( !empty( $this->history['offset'] ) ) {
                                        $join .= " AND rev_timestamp $op " . $this->db->addQuotes(
                                                $this->db->timestamp( $this->history['offset'] ) );
                                }
                                if ( !empty( $this->history['limit'] ) ) {
                                        $limitNum = intval( $this->history['limit'] );
                                        if ( $limitNum > 0 ) {
                                                $limit = "LIMIT $limitNum";
                                        }
                                }
                        } else {
                                wfProfileOut( $fname );
                                return new WikiError( "$fname given invalid history dump type." );
                        }
                        $where = ( $cond == '' ) ? '' : "$cond AND";

                        if( $this->buffer == WikiExporter::STREAM ) {
                                $prev = $this->db->bufferResults( false );
                        }
                        if( $cond == '' ) {
                                // Optimization hack for full-database dump
                                $revindex = $pageindex = $this->db->useIndexClause("PRIMARY");
                                $straight = ' /*! STRAIGHT_JOIN */ ';
                        } else {
                                $pageindex = '';
                                $revindex = '';
                                $straight = '';
                        }
                        if( $this->text == WikiExporter::STUB ) {
                                $sql = "SELECT $straight * FROM
                                        $page $pageindex,
                                        $revision $revindex
                                        WHERE $where $join
                                        $order $limit";
                        } else {
                                $sql = "SELECT $straight * FROM
                                        $page $pageindex,
                                        $revision $revindex,
                                        $text
                                        WHERE $where $join AND rev_text_id=old_id
                                        $order $limit";
                        }
                        $result = $this->db->query( $sql, $fname );
                        $wrapper = $this->db->resultObject( $result );
                        $this->outputPageStream( $wrapper );

                        if ( $this->list_authors ) {
                                $this->outputPageStream( $wrapper );
                        }

                        if( $this->buffer == WikiExporter::STREAM ) {
                                $this->db->bufferResults( $prev );
                        }
                }
                wfProfileOut( $fname );
        }

        /**
         * Runs through a query result set dumping page and revision records.
         * The result set should be sorted/grouped by page to avoid duplicate
         * page records in the output.
         *
         * The result set will be freed once complete. Should be safe for
         * streaming (non-buffered) queries, as long as it was made on a
         * separate database connection not managed by LoadBalancer; some
         * blob storage types will make queries to pull source data.
         *
         * @param $resultset ResultWrapper
         */
        protected function outputPageStream( $resultset ) {
                $last = null;
                while( $row = $resultset->fetchObject() ) {
                        if( is_null( $last ) ||
                                $last->page_namespace != $row->page_namespace ||
                                $last->page_title     != $row->page_title ) {
                                if( isset( $last ) ) {
                                        $output = '';
                                        if( $this->dumpUploads ) {
                                                $output .= $this->writer->writeUploads( $last );
                                        }
                                        $output .= $this->writer->closePage();
                                        $this->sink->writeClosePage( $output );
                                }
                                $output = $this->writer->openPage( $row );
                                $this->sink->writeOpenPage( $row, $output );
                                $last = $row;
                        }
                        $output = $this->writer->writeRevision( $row );
                        $this->sink->writeRevision( $row, $output );
                }
                if( isset( $last ) ) {
                        $output = '';
                        if( $this->dumpUploads ) {
                                $output .= $this->writer->writeUploads( $last );
                        }
                        $output .= $this->author_list;
                        $output .= $this->writer->closePage();
                        $this->sink->writeClosePage( $output );
                }
                $resultset->free();
        }
        
        protected function outputLogStream( $resultset ) {
                while( $row = $resultset->fetchObject() ) {
                        $output = $this->writer->writeLogItem( $row );
                        $this->sink->writeLogItem( $row, $output );
                }
                $resultset->free();
        }
}

/**
 * @ingroup Dump
 */
class XmlDumpWriter {

        /**
         * Returns the export schema version.
         * @return string
         */
        function schemaVersion() {
                return "0.3"; // FIXME: upgrade to 0.4 when updated XSD is ready, for the revision deletion bits
        }

        /**
         * Opens the XML output stream's root <mediawiki> element.
         * This does not include an xml directive, so is safe to include
         * as a subelement in a larger XML stream. Namespace and XML Schema
         * references are included.
         *
         * Output will be encoded in UTF-8.
         *
         * @return string
         */
        function openStream() {
                global $wgContLanguageCode;
                $ver = $this->schemaVersion();
                return Xml::element( 'mediawiki', array(
                        'xmlns'              => "http://www.mediawiki.org/xml/export-$ver/",
                        'xmlns:xsi'          => "http://www.w3.org/2001/XMLSchema-instance",
                        'xsi:schemaLocation' => "http://www.mediawiki.org/xml/export-$ver/ " .
                                                "http://www.mediawiki.org/xml/export-$ver.xsd",
                        'version'            => $ver,
                        'xml:lang'           => $wgContLanguageCode ),
                        null ) .
                        "\n" .
                        $this->siteInfo();
        }

        function siteInfo() {
                $info = array(
                        $this->sitename(),
                        $this->homelink(),
                        $this->generator(),
                        $this->caseSetting(),
                        $this->namespaces() );
                return "  <siteinfo>\n    " .
                        implode( "\n    ", $info ) .
                        "\n  </siteinfo>\n";
        }

        function sitename() {
                global $wgSitename;
                return Xml::element( 'sitename', array(), $wgSitename );
        }

        function generator() {
                global $wgVersion;
                return Xml::element( 'generator', array(), "MediaWiki $wgVersion" );
        }

        function homelink() {
                return Xml::element( 'base', array(), Title::newMainPage()->getFullUrl() );
        }

        function caseSetting() {
                global $wgCapitalLinks;
                // "case-insensitive" option is reserved for future
                $sensitivity = $wgCapitalLinks ? 'first-letter' : 'case-sensitive';
                return Xml::element( 'case', array(), $sensitivity );
        }

        function namespaces() {
                global $wgContLang;
                $spaces = "<namespaces>\n";
                foreach( $wgContLang->getFormattedNamespaces() as $ns => $title ) {
                        $spaces .= '      ' . Xml::element( 'namespace', array( 'key' => $ns ), $title ) . "\n";
                }
                $spaces .= "    </namespaces>";
                return $spaces;
        }

        /**
         * Closes the output stream with the closing root element.
         * Call when finished dumping things.
         */
        function closeStream() {
                return "</mediawiki>\n";
        }


        /**
         * Opens a <page> section on the output stream, with data
         * from the given database row.
         *
         * @param $row object
         * @return string
         * @access private
         */
        function openPage( $row ) {
                $out = "  <page>\n";
                $title = Title::makeTitle( $row->page_namespace, $row->page_title );
                $out .= '    ' . Xml::elementClean( 'title', array(), $title->getPrefixedText() ) . "\n";
                $out .= '    ' . Xml::element( 'id', array(), strval( $row->page_id ) ) . "\n";
                if( '' != $row->page_restrictions ) {
                        $out .= '    ' . Xml::element( 'restrictions', array(),
                                strval( $row->page_restrictions ) ) . "\n";
                }
                return $out;
        }

        /**
         * Closes a <page> section on the output stream.
         *
         * @access private
         */
        function closePage() {
                return "  </page>\n";
        }

        /**
         * Dumps a <revision> section on the output stream, with
         * data filled in from the given database row.
         *
         * @param $row object
         * @return string
         * @access private
         */
        function writeRevision( $row ) {
                $fname = 'WikiExporter::dumpRev';
                wfProfileIn( $fname );

                $out  = "    <revision>\n";
                $out .= "      " . Xml::element( 'id', null, strval( $row->rev_id ) ) . "\n";

                $out .= $this->writeTimestamp( $row->rev_timestamp );

                if( $row->rev_deleted & Revision::DELETED_USER ) {
                        $out .= "      " . Xml::element( 'contributor', array( 'deleted' => 'deleted' ) ) . "\n";
                } else {
                        $out .= $this->writeContributor( $row->rev_user, $row->rev_user_text );
                }

                if( $row->rev_minor_edit ) {
                        $out .=  "      <minor/>\n";
                }
                if( $row->rev_deleted & Revision::DELETED_COMMENT ) {
                        $out .= "      " . Xml::element( 'comment', array( 'deleted' => 'deleted' ) ) . "\n";
                } elseif( $row->rev_comment != '' ) {
                        $out .= "      " . Xml::elementClean( 'comment', null, strval( $row->rev_comment ) ) . "\n";
                }

                if( $row->rev_deleted & Revision::DELETED_TEXT ) {
                        $out .= "      " . Xml::element( 'text', array( 'deleted' => 'deleted' ) ) . "\n";
                } elseif( isset( $row->old_text ) ) {
                        // Raw text from the database may have invalid chars
                        $text = strval( Revision::getRevisionText( $row ) );
                        $out .= "      " . Xml::elementClean( 'text',
                                array( 'xml:space' => 'preserve' ),
                                strval( $text ) ) . "\n";
                } else {
                        // Stub output
                        $out .= "      " . Xml::element( 'text',
                                array( 'id' => $row->rev_text_id ),
                                "" ) . "\n";
                }

                $out .= "    </revision>\n";

                wfProfileOut( $fname );
                return $out;
        }
        
        /**
         * Dumps a <logitem> section on the output stream, with
         * data filled in from the given database row.
         *
         * @param $row object
         * @return string
         * @access private
         */
        function writeLogItem( $row ) {
                $fname = 'WikiExporter::writeLogItem';
                wfProfileIn( $fname );

                $out  = "    <logitem>\n";
                $out .= "      " . Xml::element( 'id', null, strval( $row->log_id ) ) . "\n";

                $out .= $this->writeTimestamp( $row->log_timestamp );

                if( $row->log_deleted & LogPage::DELETED_USER ) {
                        $out .= "      " . Xml::element( 'contributor', array( 'deleted' => 'deleted' ) ) . "\n";
                } else {
                        $out .= $this->writeContributor( $row->log_user, $row->user_name );
                }

                if( $row->log_deleted & LogPage::DELETED_COMMENT ) {
                        $out .= "      " . Xml::element( 'comment', array( 'deleted' => 'deleted' ) ) . "\n";
                } elseif( $row->log_comment != '' ) {
                        $out .= "      " . Xml::elementClean( 'comment', null, strval( $row->log_comment ) ) . "\n";
                }
                
                $out .= "      " . Xml::element( 'type', null, strval( $row->log_type ) ) . "\n";
                $out .= "      " . Xml::element( 'action', null, strval( $row->log_action ) ) . "\n";

                if( $row->log_deleted & LogPage::DELETED_ACTION ) {
                        $out .= "      " . Xml::element( 'text', array( 'deleted' => 'deleted' ) ) . "\n";
                } else {
                        $title = Title::makeTitle( $row->log_namespace, $row->log_title );
                        $out .= "      " . Xml::elementClean( 'logtitle', null, $title->getPrefixedText() ) . "\n";
                        $out .= "      " . Xml::elementClean( 'params',
                                array( 'xml:space' => 'preserve' ),
                                strval( $row->log_params ) ) . "\n";
                }

                $out .= "    </logitem>\n";

                wfProfileOut( $fname );
                return $out;
        }

        function writeTimestamp( $timestamp ) {
                $ts = wfTimestamp( TS_ISO_8601, $timestamp );
                return "      " . Xml::element( 'timestamp', null, $ts ) . "\n";
        }

        function writeContributor( $id, $text ) {
                $out = "      <contributor>\n";
                if( $id ) {
                        $out .= "        " . Xml::elementClean( 'username', null, strval( $text ) ) . "\n";
                        $out .= "        " . Xml::element( 'id', null, strval( $id ) ) . "\n";
                } else {
                        $out .= "        " . Xml::elementClean( 'ip', null, strval( $text ) ) . "\n";
                }
                $out .= "      </contributor>\n";
                return $out;
        }

        /**
         * Warning! This data is potentially inconsistent. :(
         */
        function writeUploads( $row ) {
                if( $row->page_namespace == NS_IMAGE ) {
                        $img = wfFindFile( $row->page_title );
                        if( $img ) {
                                $out = '';
                                foreach( array_reverse( $img->getHistory() ) as $ver ) {
                                        $out .= $this->writeUpload( $ver );
                                }
                                $out .= $this->writeUpload( $img );
                                return $out;
                        }
                }
                return '';
        }

        function writeUpload( $file ) {
                return "    <upload>\n" .
                        $this->writeTimestamp( $file->getTimestamp() ) .
                        $this->writeContributor( $file->getUser( 'id' ), $file->getUser( 'text' ) ) .
                        "      " . Xml::elementClean( 'comment', null, $file->getDescription() ) . "\n" .
                        "      " . Xml::element( 'filename', null, $file->getName() ) . "\n" .
                        "      " . Xml::element( 'src', null, $file->getFullUrl() ) . "\n" .
                        "      " . Xml::element( 'size', null, $file->getSize() ) . "\n" .
                        "    </upload>\n";
        }

}


/**
 * Base class for output stream; prints to stdout or buffer or whereever.
 * @ingroup Dump
 */
class DumpOutput {
        function writeOpenStream( $string ) {
                $this->write( $string );
        }

        function writeCloseStream( $string ) {
                $this->write( $string );
        }

        function writeOpenPage( $page, $string ) {
                $this->write( $string );
        }

        function writeClosePage( $string ) {
                $this->write( $string );
        }

        function writeRevision( $rev, $string ) {
                $this->write( $string );
        }
        
        function writeLogItem( $rev, $string ) {
                $this->write( $string );
        }

        /**
         * Override to write to a different stream type.
         * @return bool
         */
        function write( $string ) {
                print $string;
        }
}

/**
 * Stream outputter to send data to a file.
 * @ingroup Dump
 */
class DumpFileOutput extends DumpOutput {
        var $handle;

        function DumpFileOutput( $file ) {
                $this->handle = fopen( $file, "wt" );
        }

        function write( $string ) {
                fputs( $this->handle, $string );
        }
}

/**
 * Stream outputter to send data to a file via some filter program.
 * Even if compression is available in a library, using a separate
 * program can allow us to make use of a multi-processor system.
 * @ingroup Dump
 */
class DumpPipeOutput extends DumpFileOutput {
        function DumpPipeOutput( $command, $file = null ) {
                if( !is_null( $file ) ) {
                        $command .=  " > " . wfEscapeShellArg( $file );
                }
                $this->handle = popen( $command, "w" );
        }
}

/**
 * Sends dump output via the gzip compressor.
 * @ingroup Dump
 */
class DumpGZipOutput extends DumpPipeOutput {
        function DumpGZipOutput( $file ) {
                parent::DumpPipeOutput( "gzip", $file );
        }
}

/**
 * Sends dump output via the bgzip2 compressor.
 * @ingroup Dump
 */
class DumpBZip2Output extends DumpPipeOutput {
        function DumpBZip2Output( $file ) {
                parent::DumpPipeOutput( "bzip2", $file );
        }
}

/**
 * Sends dump output via the p7zip compressor.
 * @ingroup Dump
 */
class Dump7ZipOutput extends DumpPipeOutput {
        function Dump7ZipOutput( $file ) {
                $command = "7za a -bd -si " . wfEscapeShellArg( $file );
                // Suppress annoying useless crap from p7zip
                // Unfortunately this could suppress real error messages too
                $command .= ' >' . wfGetNull() . ' 2>&1';
                parent::DumpPipeOutput( $command );
        }
}



/**
 * Dump output filter class.
 * This just does output filtering and streaming; XML formatting is done
 * higher up, so be careful in what you do.
 * @ingroup Dump
 */
class DumpFilter {
        function DumpFilter( &$sink ) {
                $this->sink =& $sink;
        }

        function writeOpenStream( $string ) {
                $this->sink->writeOpenStream( $string );
        }

        function writeCloseStream( $string ) {
                $this->sink->writeCloseStream( $string );
        }

        function writeOpenPage( $page, $string ) {
                $this->sendingThisPage = $this->pass( $page, $string );
                if( $this->sendingThisPage ) {
                        $this->sink->writeOpenPage( $page, $string );
                }
        }

        function writeClosePage( $string ) {
                if( $this->sendingThisPage ) {
                        $this->sink->writeClosePage( $string );
                        $this->sendingThisPage = false;
                }
        }

        function writeRevision( $rev, $string ) {
                if( $this->sendingThisPage ) {
                        $this->sink->writeRevision( $rev, $string );
                }
        }
        
        function writeLogItem( $rev, $string ) {
                $this->sink->writeRevision( $rev, $string );
        }       

        /**
         * Override for page-based filter types.
         * @return bool
         */
        function pass( $page ) {
                return true;
        }
}

/**
 * Simple dump output filter to exclude all talk pages.
 * @ingroup Dump
 */
class DumpNotalkFilter extends DumpFilter {
        function pass( $page ) {
                return !MWNamespace::isTalk( $page->page_namespace );
        }
}

/**
 * Dump output filter to include or exclude pages in a given set of namespaces.
 * @ingroup Dump
 */
class DumpNamespaceFilter extends DumpFilter {
        var $invert = false;
        var $namespaces = array();

        function DumpNamespaceFilter( &$sink, $param ) {
                parent::DumpFilter( $sink );

                $constants = array(
                        "NS_MAIN"           => NS_MAIN,
                        "NS_TALK"           => NS_TALK,
                        "NS_USER"           => NS_USER,
                        "NS_USER_TALK"      => NS_USER_TALK,
                        "NS_PROJECT"        => NS_PROJECT,
                        "NS_PROJECT_TALK"   => NS_PROJECT_TALK,
                        "NS_FILE"           => NS_FILE,
                        "NS_FILE_TALK"      => NS_FILE_TALK,
                        "NS_IMAGE"          => NS_IMAGE,  // NS_IMAGE is an alias for NS_FILE
                        "NS_IMAGE_TALK"     => NS_IMAGE_TALK,
                        "NS_MEDIAWIKI"      => NS_MEDIAWIKI,
                        "NS_MEDIAWIKI_TALK" => NS_MEDIAWIKI_TALK,
                        "NS_TEMPLATE"       => NS_TEMPLATE,
                        "NS_TEMPLATE_TALK"  => NS_TEMPLATE_TALK,
                        "NS_HELP"           => NS_HELP,
                        "NS_HELP_TALK"      => NS_HELP_TALK,
                        "NS_CATEGORY"       => NS_CATEGORY,
                        "NS_CATEGORY_TALK"  => NS_CATEGORY_TALK );

                if( $param{0} == '!' ) {
                        $this->invert = true;
                        $param = substr( $param, 1 );
                }

                foreach( explode( ',', $param ) as $key ) {
                        $key = trim( $key );
                        if( isset( $constants[$key] ) ) {
                                $ns = $constants[$key];
                                $this->namespaces[$ns] = true;
                        } elseif( is_numeric( $key ) ) {
                                $ns = intval( $key );
                                $this->namespaces[$ns] = true;
                        } else {
                                throw new MWException( "Unrecognized namespace key '$key'\n" );
                        }
                }
        }

        function pass( $page ) {
                $match = isset( $this->namespaces[$page->page_namespace] );
                return $this->invert xor $match;
        }
}


/**
 * Dump output filter to include only the last revision in each page sequence.
 * @ingroup Dump
 */
class DumpLatestFilter extends DumpFilter {
        var $page, $pageString, $rev, $revString;

        function writeOpenPage( $page, $string ) {
                $this->page = $page;
                $this->pageString = $string;
        }

        function writeClosePage( $string ) {
                if( $this->rev ) {
                        $this->sink->writeOpenPage( $this->page, $this->pageString );
                        $this->sink->writeRevision( $this->rev, $this->revString );
                        $this->sink->writeClosePage( $string );
                }
                $this->rev = null;
                $this->revString = null;
                $this->page = null;
                $this->pageString = null;
        }

        function writeRevision( $rev, $string ) {
                if( $rev->rev_id == $this->page->page_latest ) {
                        $this->rev = $rev;
                        $this->revString = $string;
                }
        }
}

/**
 * Base class for output stream; prints to stdout or buffer or whereever.
 * @ingroup Dump
 */
class DumpMultiWriter {
        function DumpMultiWriter( $sinks ) {
                $this->sinks = $sinks;
                $this->count = count( $sinks );
        }

        function writeOpenStream( $string ) {
                for( $i = 0; $i < $this->count; $i++ ) {
                        $this->sinks[$i]->writeOpenStream( $string );
                }
        }

        function writeCloseStream( $string ) {
                for( $i = 0; $i < $this->count; $i++ ) {
                        $this->sinks[$i]->writeCloseStream( $string );
                }
        }

        function writeOpenPage( $page, $string ) {
                for( $i = 0; $i < $this->count; $i++ ) {
                        $this->sinks[$i]->writeOpenPage( $page, $string );
                }
        }

        function writeClosePage( $string ) {
                for( $i = 0; $i < $this->count; $i++ ) {
                        $this->sinks[$i]->writeClosePage( $string );
                }
        }

        function writeRevision( $rev, $string ) {
                for( $i = 0; $i < $this->count; $i++ ) {
                        $this->sinks[$i]->writeRevision( $rev, $string );
                }
        }
}

function xmlsafe( $string ) {
        $fname = 'xmlsafe';
        wfProfileIn( $fname );

        /**
         * The page may contain old data which has not been properly normalized.
         * Invalid UTF-8 sequences or forbidden control characters will make our
         * XML output invalid, so be sure to strip them out.
         */
        $string = UtfNormal::cleanUp( $string );

        $string = htmlspecialchars( $string );
        wfProfileOut( $fname );
        return $string;
}