1 files changed, 573 insertions, 0 deletions
diff --git a/www/wiki/includes/specials/SpecialWhatlinkshere.php b/www/wiki/includes/specials/SpecialWhatlinkshere.php
new file mode 100644
index 00000000..3080fbfe
--- /dev/null
+++ b/www/wiki/includes/specials/SpecialWhatlinkshere.php
@@ -0,0 +1,573 @@
+<?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.
+ */
+
+use Wikimedia\Rdbms\IDatabase;
+
+/**
+ * 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_REPLICA );
+
+		$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->buildSelectSubquery(
+				[ $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 = $this->getLinkRenderer()->makeKnownLink(
+			$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();
+		}
+
+		$linkRenderer = $this->getLinkRenderer();
+
+		if ( $text !== null ) {
+			$text = new HtmlArmor( $text );
+		}
+
+		// always show a "<- Links" link
+		$links = [
+			'links' => $linkRenderer->makeKnownLink(
+				$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()
+		) {
+			if ( $editText !== null ) {
+				$editText = new HtmlArmor( $editText );
+			}
+
+			$links['edit'] = $linkRenderer->makeKnownLink(
+				$target,
+				$editText,
+				[],
+				[ 'action' => 'edit' ]
+			);
+		}
+
+		// build the links html
+		return $this->getLanguage()->pipeList( $links );
+	}
+
+	function makeSelfLink( $text, $query ) {
+		if ( $text !== null ) {
+			$text = new HtmlArmor( $text );
+		}
+
+		return $this->getLinkRenderer()->makeKnownLink(
+			$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';
+	}
+}