SpecialDoubleRedirects.php

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<?php
namespace MediaWiki\Specials;
 
use MediaWiki\Content\IContentHandlerFactory;
use MediaWiki\Html\Html;
use MediaWiki\Page\LinkBatchFactory;
use MediaWiki\Skin\Skin;
use MediaWiki\SpecialPage\QueryPage;
use MediaWiki\Title\Title;
use stdClass;
use Wikimedia\Rdbms\IConnectionProvider;
use Wikimedia\Rdbms\IReadableDatabase;
use Wikimedia\Rdbms\IResultWrapper;
 
class SpecialDoubleRedirects extends QueryPage {
 
    public function __construct(
        private readonly IContentHandlerFactory $contentHandlerFactory,
        private readonly LinkBatchFactory $linkBatchFactory,
        IConnectionProvider $dbProvider
    ) {
        parent::__construct( 'DoubleRedirects' );
        $this->setDatabaseProvider( $dbProvider );
    }
 
    public function isExpensive() {
        return true;
    }
 
    public function isSyndicated() {
        return false;
    }
 
    protected function sortDescending() {
        return false;
    }
 
    protected function getPageHeader() {
        return $this->msg( 'doubleredirectstext' )->parseAsBlock();
    }
 
    private function reallyGetQueryInfo( ?int $namespace = null, ?string $title = null ): array {
        $limitToTitle = !( $namespace === null && $title === null );
        $retval = [
            'tables' => [
                'ra' => 'redirect',
                'rb' => 'redirect',
                'pa' => 'page',
                'pb' => 'page'
            ],
            'fields' => [
                'namespace' => 'pa.page_namespace',
                'title' => 'pa.page_title',
 
                'b_namespace' => 'pb.page_namespace',
                'b_title' => 'pb.page_title',
                'b_fragment' => 'ra.rd_fragment',
 
                // Select fields from redirect instead of page. Because there may
                // not actually be a page table row for this target (e.g. for interwiki redirects)
                'c_namespace' => 'rb.rd_namespace',
                'c_title' => 'rb.rd_title',
                'c_fragment' => 'rb.rd_fragment',
                'c_interwiki' => 'rb.rd_interwiki',
            ],
            'conds' => [
                'ra.rd_from = pa.page_id',
 
                // Filter out redirects where the target goes interwiki (T42353).
                // This isn't an optimization, it is required for correct results,
                // otherwise a non-double redirect like Bar -> w:Foo will show up
                // like "Bar -> Foo -> w:Foo".
                'ra.rd_interwiki' => '',
 
                'pb.page_namespace = ra.rd_namespace',
                'pb.page_title = ra.rd_title',
 
                'rb.rd_from = pb.page_id',
            ]
        ];
 
        if ( $limitToTitle ) {
            $retval['conds']['pa.page_namespace'] = $namespace;
            $retval['conds']['pa.page_title'] = $title;
        }
 
        return $retval;
    }
 
    public function getQueryInfo() {
        return $this->reallyGetQueryInfo();
    }
 
    protected function getOrderFields() {
        return [ 'ra.rd_namespace', 'ra.rd_title' ];
    }
 
    public function formatResult( $skin, $result ) {
        // If no Title B or C is in the query, it means this came from
        // querycache (which only saves the 3 columns for title A).
        // That does save the bulk of the query cost, but now we need to
        // get a little more detail about each individual entry quickly
        // using the filter of reallyGetQueryInfo.
        $deep = false;
        if ( $result ) {
            if ( isset( $result->b_namespace ) ) {
                $deep = $result;
            } else {
                $qi = $this->reallyGetQueryInfo(
                    $result->namespace,
                    $result->title
                );
                $deep = $this->getDatabaseProvider()->getReplicaDatabase()->newSelectQueryBuilder()
                    ->queryInfo( $qi )
                    ->caller( __METHOD__ )
                    ->fetchRow();
            }
        }
 
        $titleA = Title::makeTitle( $result->namespace, $result->title );
 
        $linkRenderer = $this->getLinkRenderer();
        if ( !$deep ) {
            return '<del>' . $linkRenderer->makeLink( $titleA, null, [], [ 'redirect' => 'no' ] ) . '</del>';
        }
 
        // if the page is editable, add an edit link
        if (
            // check user permissions
            $this->getAuthority()->isAllowed( 'edit' ) &&
            // check, if the content model is editable through action=edit
            $this->contentHandlerFactory->getContentHandler( $titleA->getContentModel() )
                ->supportsDirectEditing()
        ) {
            $edit = $linkRenderer->makeKnownLink(
                $titleA,
                $this->msg( 'parentheses', $this->msg( 'editlink' ) )->text(),
                [],
                [ 'action' => 'edit' ]
            );
        } else {
            $edit = '';
        }
 
        $arrow = $this->getLanguage()->getArrow();
        $contentLanguage = $this->getContentLanguage();
        $bdiAttrs = [
            'dir' => $contentLanguage->getDir(),
            'lang' => $contentLanguage->getHtmlCode(),
        ];
        $linkA = Html::rawElement( 'bdi', $bdiAttrs, $linkRenderer->makeKnownLink(
            $titleA,
            null,
            [],
            [ 'redirect' => 'no' ]
        ) );
 
        $titleB = Title::makeTitle( $deep->b_namespace, $deep->b_title );
        // We show fragment, but don't link to it, as it probably doesn't exist anymore.
        $titleBFrag = Title::makeTitle( $deep->b_namespace, $deep->b_title, $deep->b_fragment );
        $linkB = Html::rawElement( 'bdi', $bdiAttrs, $linkRenderer->makeKnownLink(
            $titleB,
            $titleBFrag->getFullText(),
            [],
            [ 'redirect' => 'no' ]
        ) );
 
        $titleC = Title::makeTitle(
            $deep->c_namespace,
            $deep->c_title,
            $deep->c_fragment,
            $deep->c_interwiki
        );
        $linkC = Html::rawElement( 'bdi', $bdiAttrs,
            $linkRenderer->makeKnownLink( $titleC, $titleC->getFullText() )
        );
 
        return ( "{$linkA} {$edit} {$arrow} {$linkB} {$arrow} {$linkC}" );
    }
 
    public function execute( $par ) {
        $this->addHelpLink( 'Help:Redirects' );
        parent::execute( $par );
    }
 
    public function preprocessResults( $db, $res ) {
        if ( !$res->numRows() ) {
            return;
        }
 
        $batch = $this->linkBatchFactory->newLinkBatch()->setCaller( __METHOD__ );
        foreach ( $res as $row ) {
            $batch->add( $row->namespace, $row->title );
            if ( isset( $row->b_namespace ) ) {
                // lazy loaded when using cached results
                $batch->add( $row->b_namespace, $row->b_title );
            }
            if ( isset( $row->c_interwiki ) && !$row->c_interwiki ) {
                // lazy loaded when using cached result, not added when interwiki link
                $batch->add( $row->c_namespace, $row->c_title );
            }
        }
        $batch->execute();
 
        // Back to start for display
        $res->seek( 0 );
    }
 
    protected function getGroupName() {
        return 'maintenance';
    }
}
 
class_alias( SpecialDoubleRedirects::class, 'SpecialDoubleRedirects' );