SpecialRecentChangesLinked.php

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<?php
use MediaWiki\MainConfigNames;
use MediaWiki\User\UserOptionsLookup;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\SelectQueryBuilder;
use Wikimedia\Rdbms\Subquery;
 
class SpecialRecentChangesLinked extends SpecialRecentChanges {
    protected $rclTargetTitle;
 
    private $loadBalancer;
 
    private $searchEngineFactory;
 
    public function __construct(
        WatchedItemStoreInterface $watchedItemStore,
        MessageCache $messageCache,
        ILoadBalancer $loadBalancer,
        UserOptionsLookup $userOptionsLookup,
        SearchEngineFactory $searchEngineFactory
    ) {
        parent::__construct(
            $watchedItemStore,
            $messageCache,
            $loadBalancer,
            $userOptionsLookup
        );
        $this->mName = 'Recentchangeslinked';
        $this->loadBalancer = $loadBalancer;
        $this->searchEngineFactory = $searchEngineFactory;
    }
 
    public function getDefaultOptions() {
        $opts = parent::getDefaultOptions();
        $opts->add( 'target', '' );
        $opts->add( 'showlinkedto', false );
 
        return $opts;
    }
 
    public function parseParameters( $par, FormOptions $opts ) {
        $opts['target'] = $par;
    }
 
    protected function doMainQuery( $tables, $select, $conds, $query_options,
        $join_conds, FormOptions $opts
    ) {
        $target = $opts['target'];
        $showlinkedto = $opts['showlinkedto'];
        $limit = $opts['limit'];
 
        if ( $target === '' ) {
            return false;
        }
        $outputPage = $this->getOutput();
        $title = Title::newFromText( $target );
        if ( !$title || $title->isExternal() ) {
            $outputPage->addHTML(
                Html::errorBox( $this->msg( 'allpagesbadtitle' )->parse(), '', 'mw-recentchangeslinked-errorbox' )
            );
            return false;
        }
 
        $outputPage->setPageTitle( $this->msg( 'recentchangeslinked-title', $title->getPrefixedText() ) );
 
        /*
         * Ordinary links are in the pagelinks table, while transclusions are
         * in the templatelinks table, categorizations in categorylinks and
         * image use in imagelinks.  We need to somehow combine all these.
         * Special:Whatlinkshere does this by firing multiple queries and
         * merging the results, but the code we inherit from our parent class
         * expects only one result set so we use UNION instead.
         */
 
        $dbr = $this->loadBalancer->getConnectionRef( ILoadBalancer::DB_REPLICA, 'recentchangeslinked' );
        $id = $title->getArticleID();
        $ns = $title->getNamespace();
        $dbkey = $title->getDBkey();
 
        $rcQuery = RecentChange::getQueryInfo();
        $tables = array_unique( array_merge( $rcQuery['tables'], $tables ) );
        $select = array_unique( array_merge( $rcQuery['fields'], $select ) );
        $join_conds = array_merge( $rcQuery['joins'], $join_conds );
 
        // Join with watchlist and watchlist_expiry tables to highlight watched rows.
        $this->addWatchlistJoins( $dbr, $tables, $select, $join_conds, $conds );
 
        // JOIN on page, used for 'last revision' filter highlight
        $tables[] = 'page';
        $join_conds['page'] = [ 'LEFT JOIN', 'rc_cur_id=page_id' ];
        $select[] = 'page_latest';
 
        $tagFilter = $opts['tagfilter'] !== '' ? explode( '|', $opts['tagfilter'] ) : [];
        ChangeTags::modifyDisplayQuery(
            $tables,
            $select,
            $conds,
            $join_conds,
            $query_options,
            $tagFilter
        );
 
        if ( $dbr->unionSupportsOrderAndLimit() ) {
            if ( count( $tagFilter ) > 1 ) {
                // ChangeTags::modifyDisplayQuery() will have added DISTINCT.
                // To prevent this from causing query performance problems, we need to add
                // a GROUP BY, and add rc_id to the ORDER BY.
                $order = [
                    'GROUP BY' => [ 'rc_timestamp', 'rc_id' ],
                    'ORDER BY' => [ 'rc_timestamp DESC', 'rc_id DESC' ]
                ];
            } else {
                $order = [ 'ORDER BY' => 'rc_timestamp DESC' ];
            }
        } else {
            $order = [];
        }
 
        if ( !$this->runMainQueryHook( $tables, $select, $conds, $query_options, $join_conds,
            $opts )
        ) {
            return false;
        }
 
        if ( $ns === NS_CATEGORY && !$showlinkedto ) {
            // special handling for categories
            // XXX: should try to make this less kludgy
            $link_tables = [ 'categorylinks' ];
            $showlinkedto = true;
        } else {
            // for now, always join on these tables; really should be configurable as in whatlinkshere
            $link_tables = [ 'pagelinks', 'templatelinks' ];
            // imagelinks only contains links to pages in NS_FILE
            if ( $ns === NS_FILE || !$showlinkedto ) {
                $link_tables[] = 'imagelinks';
            }
        }
 
        if ( $id == 0 && !$showlinkedto ) {
            return false; // nonexistent pages can't link to any pages
        }
 
        // field name prefixes for all the various tables we might want to join with
        $prefix = [
            'pagelinks' => 'pl',
            'templatelinks' => 'tl',
            'categorylinks' => 'cl',
            'imagelinks' => 'il'
        ];
 
        $subsql = []; // SELECT statements to combine with UNION
 
        foreach ( $link_tables as $link_table ) {
            $queryBuilder = $dbr->newSelectQueryBuilder();
            $linksMigration = \MediaWiki\MediaWikiServices::getInstance()->getLinksMigration();
            $queryBuilder = $queryBuilder
                ->tables( $tables )
                ->fields( $select )
                ->where( $conds )
                ->caller( __METHOD__ )
                ->options( $order + $query_options )
                ->joinConds( $join_conds );
            $pfx = $prefix[$link_table];
 
            // imagelinks and categorylinks tables have no xx_namespace field,
            // and have xx_to instead of xx_title
            if ( $link_table == 'imagelinks' ) {
                $link_ns = NS_FILE;
            } elseif ( $link_table == 'categorylinks' ) {
                $link_ns = NS_CATEGORY;
            } else {
                $link_ns = 0;
            }
 
            if ( $showlinkedto ) {
                // find changes to pages linking to this page
                if ( $link_ns ) {
                    if ( $ns != $link_ns ) {
                        continue;
                    } // should never happen, but check anyway
                    $queryBuilder->where( [ "{$pfx}_to" => $dbkey ] );
                } else {
                    if ( isset( $linksMigration::$mapping[$link_table] ) ) {
                        $queryBuilder->where( $linksMigration->getLinksConditions( $link_table, $title ) );
                    } else {
                        $queryBuilder->where( [ "{$pfx}_namespace" => $ns, "{$pfx}_title" => $dbkey ] );
                    }
                }
                $queryBuilder->join( $link_table, null, "rc_cur_id = {$pfx}_from" );
            } else {
                // find changes to pages linked from this page
                $queryBuilder->where( [ "{$pfx}_from" => $id ] );
                if ( $link_table == 'imagelinks' || $link_table == 'categorylinks' ) {
                    $queryBuilder->where( [ "rc_namespace" => $link_ns ] );
                    $queryBuilder->join( $link_table, null, "rc_title = {$pfx}_to" );
                } else {
                    // TODO: Move this to LinksMigration
                    if ( isset( $linksMigration::$mapping[$link_table] ) ) {
                        $queryInfo = $linksMigration->getQueryInfo( $link_table, $link_table );
                        list( $nsField, $titleField ) = $linksMigration->getTitleFields( $link_table );
                        if ( in_array( 'linktarget', $queryInfo['tables'] ) ) {
                            $joinTable = 'linktarget';
                        } else {
                            $joinTable = $link_table;
                        }
                        $queryBuilder->join(
                            $joinTable,
                            null,
                            [ "rc_namespace = {$nsField}", "rc_title = {$titleField}" ]
                        );
                        if ( in_array( 'linktarget', $queryInfo['tables'] ) ) {
                            $queryBuilder->joinConds( $queryInfo['joins'] );
                            $queryBuilder->table( $link_table );
                        }
                    } else {
                        $queryBuilder->join(
                            $link_table,
                            null,
                            [ "rc_namespace = {$pfx}_namespace", "rc_title = {$pfx}_title" ]
                        );
                    }
                }
            }
 
            if ( $dbr->unionSupportsOrderAndLimit() ) {
                $queryBuilder->limit( $limit );
            }
 
            $subsql[] = $queryBuilder;
        }
 
        if ( count( $subsql ) == 0 ) {
            return false; // should never happen
        }
        if ( count( $subsql ) == 1 && $dbr->unionSupportsOrderAndLimit() ) {
            $sql = $subsql[0]
                ->setMaxExecutionTime( $this->getConfig()->get( MainConfigNames::MaxExecutionTimeForExpensiveQueries ) )
                ->getSQL();
        } else {
            $sqls = array_map( static function ( $queryBuilder ) {
                return $queryBuilder->getSQL();
            }, $subsql );
            $queryBuilder = $dbr->newSelectQueryBuilder()
                ->select( '*' )
                ->from(
                    (string)( new Subquery( $dbr->unionQueries( $sqls, $dbr::UNION_DISTINCT ) ) ),
                    'main'
                )
                ->orderBy( 'rc_timestamp', SelectQueryBuilder::SORT_DESC )
                ->setMaxExecutionTime( $this->getConfig()->get( MainConfigNames::MaxExecutionTimeForExpensiveQueries ) )
                ->limit( $limit );
            $sql = $queryBuilder->getSQL();
        }
        return $dbr->query( $sql, __METHOD__ );
    }
 
    public function setTopText( FormOptions $opts ) {
        $target = $this->getTargetTitle();
        if ( $target ) {
            $this->getOutput()->addBacklinkSubtitle( $target );
            $this->getSkin()->setRelevantTitle( $target );
        }
    }
 
    public function getExtraOptions( $opts ) {
        $extraOpts = parent::getExtraOptions( $opts );
 
        $opts->consumeValues( [ 'showlinkedto', 'target' ] );
 
        $extraOpts['target'] = [ $this->msg( 'recentchangeslinked-page' )->escaped(),
            Xml::input( 'target', 40, str_replace( '_', ' ', $opts['target'] ) ) . ' ' .
            Xml::check( 'showlinkedto', $opts['showlinkedto'], [ 'id' => 'showlinkedto' ] ) . ' ' .
            Xml::label( $this->msg( 'recentchangeslinked-to' )->text(), 'showlinkedto' ) ];
 
        $this->addHelpLink( 'Help:Related changes' );
        return $extraOpts;
    }
 
    private function getTargetTitle() {
        if ( $this->rclTargetTitle === null ) {
            $opts = $this->getOptions();
            if ( isset( $opts['target'] ) && $opts['target'] !== '' ) {
                $this->rclTargetTitle = Title::newFromText( $opts['target'] );
            } else {
                $this->rclTargetTitle = false;
            }
        }
 
        return $this->rclTargetTitle;
    }
 
    public function prefixSearchSubpages( $search, $limit, $offset ) {
        return $this->prefixSearchString( $search, $limit, $offset, $this->searchEngineFactory );
    }
 
    protected function outputNoResults() {
        $targetTitle = $this->getTargetTitle();
        if ( $targetTitle === false ) {
            $this->getOutput()->addHTML(
                Html::rawElement(
                    'div',
                    [ 'class' => 'mw-changeslist-empty mw-changeslist-notargetpage' ],
                    $this->msg( 'recentchanges-notargetpage' )->parse()
                )
            );
        } elseif ( !$targetTitle || $targetTitle->isExternal() ) {
            $this->getOutput()->addHTML(
                Html::rawElement(
                    'div',
                    [ 'class' => 'mw-changeslist-empty mw-changeslist-invalidtargetpage' ],
                    $this->msg( 'allpagesbadtitle' )->parse()
                )
            );
        } else {
            parent::outputNoResults();
        }
    }
}