Expose $wgMaxArticleSize in siteinfo query api

[mediawiki.git] / includes / specials / SpecialWhatlinkshere.php

<?php
/**
 * Implements Special:Whatlinkshere
 *
 * 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
 * @todo Use some variant of Pager or something; the pagination here is lousy.
 */

/**
 * Implements Special:Whatlinkshere
 *
 * @ingroup SpecialPage
 */
class SpecialWhatLinksHere extends IncludableSpecialPage {
        /** @var FormOptions */
        protected $opts;

        protected $selfTitle;

        /** @var Title */
        protected $target;

        protected $limits = [ 20, 50, 100, 250, 500 ];

        public function __construct() {
                parent::__construct( 'Whatlinkshere' );
        }

        function execute( $par ) {
                $out = $this->getOutput();

                $this->setHeaders();
                $this->outputHeader();
                $this->addHelpLink( 'Help:What links here' );

                $opts = new FormOptions();

                $opts->add( 'target', '' );
                $opts->add( 'namespace', '', FormOptions::INTNULL );
                $opts->add( 'limit', $this->getConfig()->get( 'QueryPageDefaultLimit' ) );
                $opts->add( 'from', 0 );
                $opts->add( 'back', 0 );
                $opts->add( 'hideredirs', false );
                $opts->add( 'hidetrans', false );
                $opts->add( 'hidelinks', false );
                $opts->add( 'hideimages', false );
                $opts->add( 'invert', false );

                $opts->fetchValuesFromRequest( $this->getRequest() );
                $opts->validateIntBounds( 'limit', 0, 5000 );

                // Give precedence to subpage syntax
                if ( $par !== null ) {
                        $opts->setValue( 'target', $par );
                }

                // Bind to member variable
                $this->opts = $opts;

                $this->target = Title::newFromText( $opts->getValue( 'target' ) );
                if ( !$this->target ) {
                        if ( !$this->including() ) {
                                $out->addHTML( $this->whatlinkshereForm() );
                        }

                        return;
                }

                $this->getSkin()->setRelevantTitle( $this->target );

                $this->selfTitle = $this->getPageTitle( $this->target->getPrefixedDBkey() );

                $out->setPageTitle( $this->msg( 'whatlinkshere-title', $this->target->getPrefixedText() ) );
                $out->addBacklinkSubtitle( $this->target );
                $this->showIndirectLinks(
                        0,
                        $this->target,
                        $opts->getValue( 'limit' ),
                        $opts->getValue( 'from' ),
                        $opts->getValue( 'back' )
                );
        }

        /**
         * @param int $level Recursion level
         * @param Title $target Target title
         * @param int $limit Number of entries to display
         * @param int $from Display from this article ID (default: 0)
         * @param int $back Display from this article ID at backwards scrolling (default: 0)
         */
        function showIndirectLinks( $level, $target, $limit, $from = 0, $back = 0 ) {
                $out = $this->getOutput();
                $dbr = wfGetDB( DB_SLAVE );

                $hidelinks = $this->opts->getValue( 'hidelinks' );
                $hideredirs = $this->opts->getValue( 'hideredirs' );
                $hidetrans = $this->opts->getValue( 'hidetrans' );
                $hideimages = $target->getNamespace() != NS_FILE || $this->opts->getValue( 'hideimages' );

                $fetchlinks = ( !$hidelinks || !$hideredirs );

                // Build query conds in concert for all three tables...
                $conds['pagelinks'] = [
                        'pl_namespace' => $target->getNamespace(),
                        'pl_title' => $target->getDBkey(),
                ];
                $conds['templatelinks'] = [
                        'tl_namespace' => $target->getNamespace(),
                        'tl_title' => $target->getDBkey(),
                ];
                $conds['imagelinks'] = [
                        'il_to' => $target->getDBkey(),
                ];

                $namespace = $this->opts->getValue( 'namespace' );
                $invert = $this->opts->getValue( 'invert' );
                $nsComparison = ( $invert ? '!= ' : '= ' ) . $dbr->addQuotes( $namespace );
                if ( is_int( $namespace ) ) {
                        $conds['pagelinks'][] = "pl_from_namespace $nsComparison";
                        $conds['templatelinks'][] = "tl_from_namespace $nsComparison";
                        $conds['imagelinks'][] = "il_from_namespace $nsComparison";
                }

                if ( $from ) {
                        $conds['templatelinks'][] = "tl_from >= $from";
                        $conds['pagelinks'][] = "pl_from >= $from";
                        $conds['imagelinks'][] = "il_from >= $from";
                }

                if ( $hideredirs ) {
                        $conds['pagelinks']['rd_from'] = null;
                } elseif ( $hidelinks ) {
                        $conds['pagelinks'][] = 'rd_from is NOT NULL';
                }

                $queryFunc = function ( IDatabase $dbr, $table, $fromCol ) use (
                        $conds, $target, $limit
                ) {
                        // Read an extra row as an at-end check
                        $queryLimit = $limit + 1;
                        $on = [
                                "rd_from = $fromCol",
                                'rd_title' => $target->getDBkey(),
                                'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL'
                        ];
                        $on['rd_namespace'] = $target->getNamespace();
                        // Inner LIMIT is 2X in case of stale backlinks with wrong namespaces
                        $subQuery = $dbr->selectSQLText(
                                [ $table, 'redirect', 'page' ],
                                [ $fromCol, 'rd_from' ],
                                $conds[$table],
                                __CLASS__ . '::showIndirectLinks',
                                // Force JOIN order per T106682 to avoid large filesorts
                                [ 'ORDER BY' => $fromCol, 'LIMIT' => 2 * $queryLimit, 'STRAIGHT_JOIN' ],
                                [
                                        'page' => [ 'INNER JOIN', "$fromCol = page_id" ],
                                        'redirect' => [ 'LEFT JOIN', $on ]
                                ]
                        );
                        return $dbr->select(
                                [ 'page', 'temp_backlink_range' => "($subQuery)" ],
                                [ 'page_id', 'page_namespace', 'page_title', 'rd_from', 'page_is_redirect' ],
                                [],
                                __CLASS__ . '::showIndirectLinks',
                                [ 'ORDER BY' => 'page_id', 'LIMIT' => $queryLimit ],
                                [ 'page' => [ 'INNER JOIN', "$fromCol = page_id" ] ]
                        );
                };

                if ( $fetchlinks ) {
                        $plRes = $queryFunc( $dbr, 'pagelinks', 'pl_from' );
                }

                if ( !$hidetrans ) {
                        $tlRes = $queryFunc( $dbr, 'templatelinks', 'tl_from' );
                }

                if ( !$hideimages ) {
                        $ilRes = $queryFunc( $dbr, 'imagelinks', 'il_from' );
                }

                if ( ( !$fetchlinks || !$plRes->numRows() )
                        && ( $hidetrans || !$tlRes->numRows() )
                        && ( $hideimages || !$ilRes->numRows() )
                ) {
                        if ( 0 == $level ) {
                                if ( !$this->including() ) {
                                        $out->addHTML( $this->whatlinkshereForm() );

                                        // Show filters only if there are links
                                        if ( $hidelinks || $hidetrans || $hideredirs || $hideimages ) {
                                                $out->addHTML( $this->getFilterPanel() );
                                        }
                                        $errMsg = is_int( $namespace ) ? 'nolinkshere-ns' : 'nolinkshere';
                                        $out->addWikiMsg( $errMsg, $this->target->getPrefixedText() );
                                        $out->setStatusCode( 404 );
                                }
                        }

                        return;
                }

                // Read the rows into an array and remove duplicates
                // templatelinks comes second so that the templatelinks row overwrites the
                // pagelinks row, so we get (inclusion) rather than nothing
                if ( $fetchlinks ) {
                        foreach ( $plRes as $row ) {
                                $row->is_template = 0;
                                $row->is_image = 0;
                                $rows[$row->page_id] = $row;
                        }
                }
                if ( !$hidetrans ) {
                        foreach ( $tlRes as $row ) {
                                $row->is_template = 1;
                                $row->is_image = 0;
                                $rows[$row->page_id] = $row;
                        }
                }
                if ( !$hideimages ) {
                        foreach ( $ilRes as $row ) {
                                $row->is_template = 0;
                                $row->is_image = 1;
                                $rows[$row->page_id] = $row;
                        }
                }

                // Sort by key and then change the keys to 0-based indices
                ksort( $rows );
                $rows = array_values( $rows );

                $numRows = count( $rows );

                // Work out the start and end IDs, for prev/next links
                if ( $numRows > $limit ) {
                        // More rows available after these ones
                        // Get the ID from the last row in the result set
                        $nextId = $rows[$limit]->page_id;
                        // Remove undisplayed rows
                        $rows = array_slice( $rows, 0, $limit );
                } else {
                        // No more rows after
                        $nextId = false;
                }
                $prevId = $from;

                // use LinkBatch to make sure, that all required data (associated with Titles)
                // is loaded in one query
                $lb = new LinkBatch();
                foreach ( $rows as $row ) {
                        $lb->add( $row->page_namespace, $row->page_title );
                }
                $lb->execute();

                if ( $level == 0 ) {
                        if ( !$this->including() ) {
                                $out->addHTML( $this->whatlinkshereForm() );
                                $out->addHTML( $this->getFilterPanel() );
                                $out->addWikiMsg( 'linkshere', $this->target->getPrefixedText() );

                                $prevnext = $this->getPrevNext( $prevId, $nextId );
                                $out->addHTML( $prevnext );
                        }
                }
                $out->addHTML( $this->listStart( $level ) );
                foreach ( $rows as $row ) {
                        $nt = Title::makeTitle( $row->page_namespace, $row->page_title );

                        if ( $row->rd_from && $level < 2 ) {
                                $out->addHTML( $this->listItem( $row, $nt, $target, true ) );
                                $this->showIndirectLinks(
                                        $level + 1,
                                        $nt,
                                        $this->getConfig()->get( 'MaxRedirectLinksRetrieved' )
                                );
                                $out->addHTML( Xml::closeElement( 'li' ) );
                        } else {
                                $out->addHTML( $this->listItem( $row, $nt, $target ) );
                        }
                }

                $out->addHTML( $this->listEnd() );

                if ( $level == 0 ) {
                        if ( !$this->including() ) {
                                $out->addHTML( $prevnext );
                        }
                }
        }

        protected function listStart( $level ) {
                return Xml::openElement( 'ul', ( $level ? [] : [ 'id' => 'mw-whatlinkshere-list' ] ) );
        }

        protected function listItem( $row, $nt, $target, $notClose = false ) {
                $dirmark = $this->getLanguage()->getDirMark();

                # local message cache
                static $msgcache = null;
                if ( $msgcache === null ) {
                        static $msgs = [ 'isredirect', 'istemplate', 'semicolon-separator',
                                'whatlinkshere-links', 'isimage', 'editlink' ];
                        $msgcache = [];
                        foreach ( $msgs as $msg ) {
                                $msgcache[$msg] = $this->msg( $msg )->escaped();
                        }
                }

                if ( $row->rd_from ) {
                        $query = [ 'redirect' => 'no' ];
                } else {
                        $query = [];
                }

                $link = Linker::linkKnown(
                        $nt,
                        null,
                        $row->page_is_redirect ? [ 'class' => 'mw-redirect' ] : [],
                        $query
                );

                // Display properties (redirect or template)
                $propsText = '';
                $props = [];
                if ( $row->rd_from ) {
                        $props[] = $msgcache['isredirect'];
                }
                if ( $row->is_template ) {
                        $props[] = $msgcache['istemplate'];
                }
                if ( $row->is_image ) {
                        $props[] = $msgcache['isimage'];
                }

                Hooks::run( 'WhatLinksHereProps', [ $row, $nt, $target, &$props ] );

                if ( count( $props ) ) {
                        $propsText = $this->msg( 'parentheses' )
                                ->rawParams( implode( $msgcache['semicolon-separator'], $props ) )->escaped();
                }

                # Space for utilities links, with a what-links-here link provided
                $wlhLink = $this->wlhLink( $nt, $msgcache['whatlinkshere-links'], $msgcache['editlink'] );
                $wlh = Xml::wrapClass(
                        $this->msg( 'parentheses' )->rawParams( $wlhLink )->escaped(),
                        'mw-whatlinkshere-tools'
                );

                return $notClose ?
                        Xml::openElement( 'li' ) . "$link $propsText $dirmark $wlh\n" :
                        Xml::tags( 'li', null, "$link $propsText $dirmark $wlh" ) . "\n";
        }

        protected function listEnd() {
                return Xml::closeElement( 'ul' );
        }

        protected function wlhLink( Title $target, $text, $editText ) {
                static $title = null;
                if ( $title === null ) {
                        $title = $this->getPageTitle();
                }

                // always show a "<- Links" link
                $links = [
                        'links' => Linker::linkKnown(
                                $title,
                                $text,
                                [],
                                [ 'target' => $target->getPrefixedText() ]
                        ),
                ];

                // if the page is editable, add an edit link
                if (
                        // check user permissions
                        $this->getUser()->isAllowed( 'edit' ) &&
                        // check, if the content model is editable through action=edit
                        ContentHandler::getForTitle( $target )->supportsDirectEditing()
                ) {
                        $links['edit'] = Linker::linkKnown(
                                $target,
                                $editText,
                                [],
                                [ 'action' => 'edit' ]
                        );
                }

                // build the links html
                return $this->getLanguage()->pipeList( $links );
        }

        function makeSelfLink( $text, $query ) {
                return Linker::linkKnown(
                        $this->selfTitle,
                        $text,
                        [],
                        $query
                );
        }

        function getPrevNext( $prevId, $nextId ) {
                $currentLimit = $this->opts->getValue( 'limit' );
                $prev = $this->msg( 'whatlinkshere-prev' )->numParams( $currentLimit )->escaped();
                $next = $this->msg( 'whatlinkshere-next' )->numParams( $currentLimit )->escaped();

                $changed = $this->opts->getChangedValues();
                unset( $changed['target'] ); // Already in the request title

                if ( 0 != $prevId ) {
                        $overrides = [ 'from' => $this->opts->getValue( 'back' ) ];
                        $prev = $this->makeSelfLink( $prev, array_merge( $changed, $overrides ) );
                }
                if ( 0 != $nextId ) {
                        $overrides = [ 'from' => $nextId, 'back' => $prevId ];
                        $next = $this->makeSelfLink( $next, array_merge( $changed, $overrides ) );
                }

                $limitLinks = [];
                $lang = $this->getLanguage();
                foreach ( $this->limits as $limit ) {
                        $prettyLimit = htmlspecialchars( $lang->formatNum( $limit ) );
                        $overrides = [ 'limit' => $limit ];
                        $limitLinks[] = $this->makeSelfLink( $prettyLimit, array_merge( $changed, $overrides ) );
                }

                $nums = $lang->pipeList( $limitLinks );

                return $this->msg( 'viewprevnext' )->rawParams( $prev, $next, $nums )->escaped();
        }

        function whatlinkshereForm() {
                // We get nicer value from the title object
                $this->opts->consumeValue( 'target' );
                // Reset these for new requests
                $this->opts->consumeValues( [ 'back', 'from' ] );

                $target = $this->target ? $this->target->getPrefixedText() : '';
                $namespace = $this->opts->consumeValue( 'namespace' );
                $nsinvert = $this->opts->consumeValue( 'invert' );

                # Build up the form
                $f = Xml::openElement( 'form', [ 'action' => wfScript() ] );

                # Values that should not be forgotten
                $f .= Html::hidden( 'title', $this->getPageTitle()->getPrefixedText() );
                foreach ( $this->opts->getUnconsumedValues() as $name => $value ) {
                        $f .= Html::hidden( $name, $value );
                }

                $f .= Xml::fieldset( $this->msg( 'whatlinkshere' )->text() );

                # Target input (.mw-searchInput enables suggestions)
                $f .= Xml::inputLabel( $this->msg( 'whatlinkshere-page' )->text(), 'target',
                        'mw-whatlinkshere-target', 40, $target, [ 'class' => 'mw-searchInput' ] );

                $f .= ' ';

                # Namespace selector
                $f .= Html::namespaceSelector(
                        [
                                'selected' => $namespace,
                                'all' => '',
                                'label' => $this->msg( 'namespace' )->text()
                        ], [
                                'name' => 'namespace',
                                'id' => 'namespace',
                                'class' => 'namespaceselector',
                        ]
                );

                $f .= '&#160;' .
                        Xml::checkLabel(
                                $this->msg( 'invert' )->text(),
                                'invert',
                                'nsinvert',
                                $nsinvert,
                                [ 'title' => $this->msg( 'tooltip-whatlinkshere-invert' )->text() ]
                        );

                $f .= ' ';

                # Submit
                $f .= Xml::submitButton( $this->msg( 'whatlinkshere-submit' )->text() );

                # Close
                $f .= Xml::closeElement( 'fieldset' ) . Xml::closeElement( 'form' ) . "\n";

                return $f;
        }

        /**
         * Create filter panel
         *
         * @return string HTML fieldset and filter panel with the show/hide links
         */
        function getFilterPanel() {
                $show = $this->msg( 'show' )->escaped();
                $hide = $this->msg( 'hide' )->escaped();

                $changed = $this->opts->getChangedValues();
                unset( $changed['target'] ); // Already in the request title

                $links = [];
                $types = [ 'hidetrans', 'hidelinks', 'hideredirs' ];
                if ( $this->target->getNamespace() == NS_FILE ) {
                        $types[] = 'hideimages';
                }

                // Combined message keys: 'whatlinkshere-hideredirs', 'whatlinkshere-hidetrans',
                // 'whatlinkshere-hidelinks', 'whatlinkshere-hideimages'
                // To be sure they will be found by grep
                foreach ( $types as $type ) {
                        $chosen = $this->opts->getValue( $type );
                        $msg = $chosen ? $show : $hide;
                        $overrides = [ $type => !$chosen ];
                        $links[] = $this->msg( "whatlinkshere-{$type}" )->rawParams(
                                $this->makeSelfLink( $msg, array_merge( $changed, $overrides ) ) )->escaped();
                }

                return Xml::fieldset(
                        $this->msg( 'whatlinkshere-filters' )->text(),
                        $this->getLanguage()->pipeList( $links )
                );
        }

        /**
         * Return an array of subpages beginning with $search that this special page will accept.
         *
         * @param string $search Prefix to search for
         * @param int $limit Maximum number of results to return (usually 10)
         * @param int $offset Number of results to skip (usually 0)
         * @return string[] Matching subpages
         */
        public function prefixSearchSubpages( $search, $limit, $offset ) {
                return $this->prefixSearchString( $search, $limit, $offset );
        }

        protected function getGroupName() {
                return 'pagetools';
        }
}