wikimedia/mediawiki-core

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includes/specials/SpecialDoubleRedirects.php

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<?php
/**
 * Implements Special:DoubleRedirects
 *
 * 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
 *
 * @file
 * @ingroup SpecialPage
 */

namespace MediaWiki\Specials;

use MediaWiki\Cache\LinkBatchFactory;
use MediaWiki\Content\IContentHandlerFactory;
use MediaWiki\SpecialPage\QueryPage;
use MediaWiki\Title\Title;
use Skin;
use stdClass;
use Wikimedia\Rdbms\IConnectionProvider;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\IResultWrapper;

/**
 * A special page listing redirects to redirecting page.
 * The software will automatically not follow double redirects, to prevent loops.
 *
 * @ingroup SpecialPage
 */
class SpecialDoubleRedirects extends QueryPage {

    private IContentHandlerFactory $contentHandlerFactory;
    private LinkBatchFactory $linkBatchFactory;

    /**
     * @param IContentHandlerFactory $contentHandlerFactory
     * @param LinkBatchFactory $linkBatchFactory
     * @param IConnectionProvider $dbProvider
     */
    public function __construct(
        IContentHandlerFactory $contentHandlerFactory,
        LinkBatchFactory $linkBatchFactory,
        IConnectionProvider $dbProvider
    ) {
        parent::__construct( 'DoubleRedirects' );
        $this->contentHandlerFactory = $contentHandlerFactory;
        $this->linkBatchFactory = $linkBatchFactory;
        $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( $namespace = null, $title = null ) {
        $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' ];
    }

    /**
     * @param Skin $skin
     * @param stdClass $result Result row
     * @return string
     */
    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() )->text(),
                [],
                [ 'action' => 'edit' ]
            );
        } else {
            $edit = '';
        }

        $linkA = $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 = $linkRenderer->makeKnownLink(
            $titleB,
            $titleBFrag->getFullText(),
            [],
            [ 'redirect' => 'no' ]
        );

        $titleC = Title::makeTitle(
            $deep->c_namespace,
            $deep->c_title,
            $deep->c_fragment,
            $deep->c_interwiki
        );
        $linkC = $linkRenderer->makeKnownLink( $titleC, $titleC->getFullText() );

        $lang = $this->getLanguage();
        $arr = $lang->getArrow() . $lang->getDirMark();

        return ( "{$linkA} {$edit} {$arr} {$linkB} {$arr} {$linkC}" );
    }

    public function execute( $par ) {
        $this->addHelpLink( 'Help:Redirects' );
        parent::execute( $par );
    }

    /**
     * Cache page content model and gender distinction for performance
     *
     * @param IDatabase $db
     * @param IResultWrapper $res
     */
    public function preprocessResults( $db, $res ) {
        if ( !$res->numRows() ) {
            return;
        }

        $batch = $this->linkBatchFactory->newLinkBatch();
        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';
    }
}

/** @deprecated class alias since 1.41 */
class_alias( SpecialDoubleRedirects::class, 'SpecialDoubleRedirects' );