DoubleRedirectJob.php

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<?php
class DoubleRedirectJob extends Job {
        var $reason, $redirTitle;

        static $user;

        public static function fixRedirects( $reason, $redirTitle, $destTitle = false ) {
                # Need to use the master to get the redirect table updated in the same transaction
                $dbw = wfGetDB( DB_MASTER );
                $res = $dbw->select(
                        array( 'redirect', 'page' ),
                        array( 'page_namespace', 'page_title' ),
                        array(
                                'page_id = rd_from',
                                'rd_namespace' => $redirTitle->getNamespace(),
                                'rd_title' => $redirTitle->getDBkey()
                        ), __METHOD__ );
                if ( !$res->numRows() ) {
                        return;
                }
                $jobs = array();
                foreach ( $res as $row ) {
                        $title = Title::makeTitle( $row->page_namespace, $row->page_title );
                        if ( !$title ) {
                                continue;
                        }

                        $jobs[] = new self( $title, array(
                                'reason' => $reason,
                                'redirTitle' => $redirTitle->getPrefixedDBkey() ) );
                        # Avoid excessive memory usage
                        if ( count( $jobs ) > 10000 ) {
                                Job::batchInsert( $jobs );
                                $jobs = array();
                        }
                }
                Job::batchInsert( $jobs );
        }

        function __construct( $title, $params = false, $id = 0 ) {
                parent::__construct( 'fixDoubleRedirect', $title, $params, $id );
                $this->reason = $params['reason'];
                $this->redirTitle = Title::newFromText( $params['redirTitle'] );
        }

        function run() {
                if ( !$this->redirTitle ) {
                        $this->setLastError( 'Invalid title' );
                        return false;
                }

                $targetRev = Revision::newFromTitle( $this->title, false, Revision::READ_LATEST );
                if ( !$targetRev ) {
                        wfDebug( __METHOD__.": target redirect already deleted, ignoring\n" );
                        return true;
                }
                $content = $targetRev->getContent();
                $currentDest = $content->getRedirectTarget();
                if ( !$currentDest || !$currentDest->equals( $this->redirTitle ) ) {
                        wfDebug( __METHOD__.": Redirect has changed since the job was queued\n" );
                        return true;
                }

                # Check for a suppression tag (used e.g. in periodically archived discussions)
                $mw = MagicWord::get( 'staticredirect' );
                if ( $content->matchMagicWord( $mw ) ) {
                        wfDebug( __METHOD__.": skipping: suppressed with __STATICREDIRECT__\n" );
                        return true;
                }

                # Find the current final destination
                $newTitle = self::getFinalDestination( $this->redirTitle );
                if ( !$newTitle ) {
                        wfDebug( __METHOD__.": skipping: single redirect, circular redirect or invalid redirect destination\n" );
                        return true;
                }
                if ( $newTitle->equals( $this->redirTitle ) ) {
                        # The redirect is already right, no need to change it
                        # This can happen if the page was moved back (say after vandalism)
                        wfDebug( __METHOD__.": skipping, already good\n" );
                }

                # Preserve fragment (bug 14904)
                $newTitle = Title::makeTitle( $newTitle->getNamespace(), $newTitle->getDBkey(),
                        $currentDest->getFragment(), $newTitle->getInterwiki() );

                # Fix the text
                $newContent = $content->updateRedirect( $newTitle );

                if ( $newContent->equals( $content ) ) {
                        $this->setLastError( 'Content unchanged???' );
                        return false;
                }

                # Save it
                global $wgUser;
                $oldUser = $wgUser;
                $wgUser = $this->getUser();
                $article = WikiPage::factory( $this->title );
                $reason = wfMessage( 'double-redirect-fixed-' . $this->reason,
                        $this->redirTitle->getPrefixedText(), $newTitle->getPrefixedText()
                )->inContentLanguage()->text();
                $article->doEditContent( $newContent, $reason, EDIT_UPDATE | EDIT_SUPPRESS_RC, false, $this->getUser() );
                $wgUser = $oldUser;

                return true;
        }

        public static function getFinalDestination( $title ) {
                $dbw = wfGetDB( DB_MASTER );

                $seenTitles = array(); # Circular redirect check
                $dest = false;

                while ( true ) {
                        $titleText = $title->getPrefixedDBkey();
                        if ( isset( $seenTitles[$titleText] ) ) {
                                wfDebug( __METHOD__, "Circular redirect detected, aborting\n" );
                                return false;
                        }
                        $seenTitles[$titleText] = true;

                        if ( $title->getInterwiki() ) {
                                // If the target is interwiki, we have to break early (bug 40352).
                                // Otherwise it will look up a row in the local page table
                                // with the namespace/page of the interwiki target which can cause
                                // unexpected results (e.g. X -> foo:Bar -> Bar -> .. )
                                break;
                        }

                        $row = $dbw->selectRow(
                                array( 'redirect', 'page' ),
                                array( 'rd_namespace', 'rd_title', 'rd_interwiki' ),
                                array(
                                        'rd_from=page_id',
                                        'page_namespace' => $title->getNamespace(),
                                        'page_title' => $title->getDBkey()
                                ), __METHOD__ );
                        if ( !$row ) {
                                # No redirect from here, chain terminates
                                break;
                        } else {
                                $dest = $title = Title::makeTitle( $row->rd_namespace, $row->rd_title, '', $row->rd_interwiki );
                        }
                }
                return $dest;
        }

        function getUser() {
                if ( !self::$user ) {
                        self::$user = User::newFromName( wfMessage( 'double-redirect-fixer' )->inContentLanguage()->text(), false );
                        # FIXME: newFromName could return false on a badly configured wiki.
                        if ( !self::$user->isLoggedIn() ) {
                                self::$user->addToDatabase();
                        }
                }
                return self::$user;
        }
}