DoubleRedirectJob.php

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<?php
class DoubleRedirectJob extends Job {
    private $reason;

    private $redirTitle;

    private static $user;

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

    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(
            [ 'redirect', 'page' ],
            [ 'page_namespace', 'page_title' ],
            [
                'page_id = rd_from',
                'rd_namespace' => $redirTitle->getNamespace(),
                'rd_title' => $redirTitle->getDBkey()
            ], __METHOD__ );
        if ( !$res->numRows() ) {
            return;
        }
        $jobs = [];
        foreach ( $res as $row ) {
            $title = Title::makeTitle( $row->page_namespace, $row->page_title );
            if ( !$title ) {
                continue;
            }

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

    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 ? $content->getRedirectTarget() : null;
        if ( !$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;
        }

        $user = $this->getUser();
        if ( !$user ) {
            $this->setLastError( 'Invalid user' );

            return false;
        }

        // Save it
        global $wgUser;
        $oldUser = $wgUser;
        $wgUser = $user;
        $article = WikiPage::factory( $this->title );

        // Messages: double-redirect-fixed-move, double-redirect-fixed-maintenance
        $reason = wfMessage( 'double-redirect-fixed-' . $this->reason,
            $this->redirTitle->getPrefixedText(), $newTitle->getPrefixedText()
        )->inContentLanguage()->text();
        $flags = EDIT_UPDATE | EDIT_SUPPRESS_RC | EDIT_INTERNAL;
        $article->doEditContent( $newContent, $reason, $flags, false, $user );
        $wgUser = $oldUser;

        return true;
    }

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

        // Circular redirect check
        $seenTitles = [];
        $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->isExternal() ) {
                // 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(
                [ 'redirect', 'page' ],
                [ 'rd_namespace', 'rd_title', 'rd_interwiki' ],
                [
                    '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 ) {
            $username = wfMessage( 'double-redirect-fixer' )->inContentLanguage()->text();
            self::$user = User::newFromName( $username );
            # User::newFromName() can return false on a badly configured wiki.
            if ( self::$user && !self::$user->isLoggedIn() ) {
                self::$user->addToDatabase();
            }
        }

        return self::$user;
    }
}