SpecialWhatlinkshere.php

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<?php
class SpecialWhatLinksHere extends SpecialPage {

        protected $opts;

        protected $selfTitle;

        protected $target;

        protected $limits = array( 20, 50, 100, 250, 500 );

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

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

                $this->setHeaders();
                $this->outputHeader();

                $opts = new FormOptions();

                $opts->add( 'target', '' );
                $opts->add( 'namespace', '', FormOptions::INTNULL );
                $opts->add( 'limit', $wgQueryPageDefaultLimit );
                $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->fetchValuesFromRequest( $this->getRequest() );
                $opts->validateIntBounds( 'limit', 0, 5000 );

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

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

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

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

                $this->selfTitle = $this->getTitle( $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' ) );
        }

        function showIndirectLinks( $level, $target, $limit, $from = 0, $back = 0 ) {
                global $wgMaxRedirectLinksRetrieved;
                $out = $this->getOutput();
                $dbr = wfGetDB( DB_SLAVE );
                $options = array();

                $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);

                // Make the query
                $plConds = array(
                        'page_id=pl_from',
                        'pl_namespace' => $target->getNamespace(),
                        'pl_title' => $target->getDBkey(),
                );
                if( $hideredirs ) {
                        $plConds['rd_from'] = null;
                } elseif( $hidelinks ) {
                        $plConds[] = 'rd_from is NOT NULL';
                }

                $tlConds = array(
                        'page_id=tl_from',
                        'tl_namespace' => $target->getNamespace(),
                        'tl_title' => $target->getDBkey(),
                );

                $ilConds = array(
                        'page_id=il_from',
                        'il_to' => $target->getDBkey(),
                );

                $namespace = $this->opts->getValue( 'namespace' );
                if ( is_int($namespace) ) {
                        $plConds['page_namespace'] = $namespace;
                        $tlConds['page_namespace'] = $namespace;
                        $ilConds['page_namespace'] = $namespace;
                }

                if ( $from ) {
                        $tlConds[] = "tl_from >= $from";
                        $plConds[] = "pl_from >= $from";
                        $ilConds[] = "il_from >= $from";
                }

                // Read an extra row as an at-end check
                $queryLimit = $limit + 1;

                // Enforce join order, sometimes namespace selector may
                // trigger filesorts which are far less efficient than scanning many entries
                $options[] = 'STRAIGHT_JOIN';

                $options['LIMIT'] = $queryLimit;
                $fields = array( 'page_id', 'page_namespace', 'page_title', 'rd_from' );

                $joinConds = array( 'redirect' => array( 'LEFT JOIN', array(
                        'rd_from = page_id',
                        'rd_namespace' => $target->getNamespace(),
                        'rd_title' => $target->getDBkey(),
                        'rd_interwiki = ' . $dbr->addQuotes( '' ) . ' OR rd_interwiki IS NULL'
                )));

                if( $fetchlinks ) {
                        $options['ORDER BY'] = 'pl_from';
                        $plRes = $dbr->select( array( 'pagelinks', 'page', 'redirect' ), $fields,
                                $plConds, __METHOD__, $options,
                                $joinConds);
                }

                if( !$hidetrans ) {
                        $options['ORDER BY'] = 'tl_from';
                        $tlRes = $dbr->select( array( 'templatelinks', 'page', 'redirect' ), $fields,
                                $tlConds, __METHOD__, $options,
                                $joinConds);
                }

                if( !$hideimages ) {
                        $options['ORDER BY'] = 'il_from';
                        $ilRes = $dbr->select( array( 'imagelinks', 'page', 'redirect' ), $fields,
                                $ilConds, __METHOD__, $options,
                                $joinConds);
                }

                if( ( !$fetchlinks || !$dbr->numRows($plRes) ) && ( $hidetrans || !$dbr->numRows($tlRes) ) && ( $hideimages || !$dbr->numRows($ilRes) ) ) {
                        if ( 0 == $level ) {
                                $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() );
                        }
                        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;

                if ( $level == 0 ) {
                        $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, true ) );
                                $this->showIndirectLinks( $level + 1, $nt, $wgMaxRedirectLinksRetrieved );
                                $out->addHTML( Xml::closeElement( 'li' ) );
                        } else {
                                $out->addHTML( $this->listItem( $row, $nt ) );
                        }
                }

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

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

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

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

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

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

                $link = Linker::linkKnown(
                        $nt,
                        null,
                        array(),
                        $query
                );

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

                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'] );
                $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 ) {
                static $title = null;
                if ( $title === null )
                        $title = $this->getTitle();

                return Linker::linkKnown(
                        $title,
                        $text,
                        array(),
                        array( 'target' => $target->getPrefixedText() )
                );
        }

        function makeSelfLink( $text, $query ) {
                return Linker::linkKnown(
                        $this->selfTitle,
                        $text,
                        array(),
                        $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 = array( 'from' => $this->opts->getValue( 'back' ) );
                        $prev = $this->makeSelfLink( $prev, array_merge( $changed, $overrides ) );
                }
                if ( 0 != $nextId ) {
                        $overrides = array( 'from' => $nextId, 'back' => $prevId );
                        $next = $this->makeSelfLink( $next, array_merge( $changed, $overrides ) );
                }

                $limitLinks = array();
                $lang = $this->getLanguage();
                foreach ( $this->limits as $limit ) {
                        $prettyLimit = htmlspecialchars( $lang->formatNum( $limit ) );
                        $overrides = array( '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() {
                global $wgScript;

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

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

                # Build up the form
                $f = Xml::openElement( 'form', array( 'action' => $wgScript ) );

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

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

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

                $f .= ' ';

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

                $f .= ' ';

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

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

                return $f;
        }

        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 = array();
                $types = array( '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 = array( $type => !$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 ) );
        }
}