SpecialRecentChangesLinked.php

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<?php
class SpecialRecentChangesLinked extends SpecialRecentChanges {
    protected $rclTargetTitle;

    function __construct() {
        parent::__construct( 'Recentchangeslinked' );
    }

    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() )
            );
            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 = wfGetDB( DB_REPLICA, 'recentchangeslinked' );
        $id = $title->getArticleID();
        $ns = $title->getNamespace();
        $dbkey = $title->getDBkey();

        $rcQuery = RecentChange::getQueryInfo();
        $tables = array_merge( $tables, $rcQuery['tables'] );
        $select = array_merge( $rcQuery['fields'], $select );
        $join_conds = array_merge( $join_conds, $rcQuery['joins'] );

        // left join with watchlist table to highlight watched rows
        $uid = $this->getUser()->getId();
        if ( $uid && $this->getUser()->isAllowed( 'viewmywatchlist' ) ) {
            $tables[] = 'watchlist';
            $select[] = 'wl_user';
            $join_conds['watchlist'] = [ 'LEFT JOIN', [
                'wl_user' => $uid,
                'wl_title=rc_title',
                'wl_namespace=rc_namespace'
            ] ];
        }

        // 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 ) {
            $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
                    $subconds = [ "{$pfx}_to" => $dbkey ];
                } else {
                    $subconds = [ "{$pfx}_namespace" => $ns, "{$pfx}_title" => $dbkey ];
                }
                $subjoin = "rc_cur_id = {$pfx}_from";
            } else {
                // find changes to pages linked from this page
                $subconds = [ "{$pfx}_from" => $id ];
                if ( $link_table == 'imagelinks' || $link_table == 'categorylinks' ) {
                    $subconds["rc_namespace"] = $link_ns;
                    $subjoin = "rc_title = {$pfx}_to";
                } else {
                    $subjoin = [ "rc_namespace = {$pfx}_namespace", "rc_title = {$pfx}_title" ];
                }
            }

            $query = $dbr->selectSQLText(
                array_merge( $tables, [ $link_table ] ),
                $select,
                $conds + $subconds,
                __METHOD__,
                $order + $query_options,
                $join_conds + [ $link_table => [ 'JOIN', $subjoin ] ]
            );

            if ( $dbr->unionSupportsOrderAndLimit() ) {
                $query = $dbr->limitResult( $query, $limit );
            }

            $subsql[] = $query;
        }

        if ( count( $subsql ) == 0 ) {
            return false; // should never happen
        }
        if ( count( $subsql ) == 1 && $dbr->unionSupportsOrderAndLimit() ) {
            $sql = $subsql[0];
        } else {
            // need to resort and relimit after union
            $sql = $dbr->unionQueries( $subsql, $dbr::UNION_DISTINCT ) .
                ' ORDER BY rc_timestamp DESC';
            $sql = $dbr->limitResult( $sql, $limit, false );
        }

        $res = $dbr->query( $sql, __METHOD__ );

        if ( $res->numRows() == 0 ) {
            $this->mResultEmpty = true;
        }

        return $res;
    }

    function setTopText( FormOptions $opts ) {
        $target = $this->getTargetTitle();
        if ( $target ) {
            $this->getOutput()->addBacklinkSubtitle( $target );
            $this->getSkin()->setRelevantTitle( $target );
        }
    }

    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;
    }

    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 );
    }

    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();
        }
    }
}