includes/specials/SpecialDoubleRedirects.php

   1 <?php
   2 /**
   3  * Implements Special:DoubleRedirects
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup SpecialPage
  22  */
  23
  24 use Wikimedia\Rdbms\IResultWrapper;
  25 use Wikimedia\Rdbms\IDatabase;
  26
  27 /**
  28  * A special page listing redirects to redirecting page.
  29  * The software will automatically not follow double redirects, to prevent loops.
  30  *
  31  * @ingroup SpecialPage
  32  */
  33 class DoubleRedirectsPage extends QueryPage {
  34         function __construct( $name = 'DoubleRedirects' ) {
  35                 parent::__construct( $name );
  36         }
  37
  38         public function isExpensive() {
  39                 return true;
  40         }
  41
  42         function isSyndicated() {
  43                 return false;
  44         }
  45
  46         function sortDescending() {
  47                 return false;
  48         }
  49
  50         function getPageHeader() {
  51                 return $this->msg( 'doubleredirectstext' )->parseAsBlock();
  52         }
  53
  54         function reallyGetQueryInfo( $namespace = null, $title = null ) {
  55                 $limitToTitle = !( $namespace === null && $title === null );
  56                 $dbr = wfGetDB( DB_REPLICA );
  57                 $retval = [
  58                         'tables' => [
  59                                 'ra' => 'redirect',
  60                                 'rb' => 'redirect',
  61                                 'pa' => 'page',
  62                                 'pb' => 'page'
  63                         ],
  64                         'fields' => [
  65                                 'namespace' => 'pa.page_namespace',
  66                                 'title' => 'pa.page_title',
  67
  68                                 'b_namespace' => 'pb.page_namespace',
  69                                 'b_title' => 'pb.page_title',
  70
  71                                 // Select fields from redirect instead of page. Because there may
  72                                 // not actually be a page table row for this target (e.g. for interwiki redirects)
  73                                 'c_namespace' => 'rb.rd_namespace',
  74                                 'c_title' => 'rb.rd_title',
  75                                 'c_fragment' => 'rb.rd_fragment',
  76                                 'c_interwiki' => 'rb.rd_interwiki',
  77                         ],
  78                         'conds' => [
  79                                 'ra.rd_from = pa.page_id',
  80
  81                                 // Filter out redirects where the target goes interwiki (T42353).
  82                                 // This isn't an optimization, it is required for correct results,
  83                                 // otherwise a non-double redirect like Bar -> w:Foo will show up
  84                                 // like "Bar -> Foo -> w:Foo".
  85
  86                                 // Need to check both NULL and "" for some reason,
  87                                 // apparently either can be stored for non-iw entries.
  88                                 'ra.rd_interwiki IS NULL OR ra.rd_interwiki = ' . $dbr->addQuotes( '' ),
  89
  90                                 'pb.page_namespace = ra.rd_namespace',
  91                                 'pb.page_title = ra.rd_title',
  92
  93                                 'rb.rd_from = pb.page_id',
  94                         ]
  95                 ];
  96
  97                 if ( $limitToTitle ) {
  98                         $retval['conds']['pa.page_namespace'] = $namespace;
  99                         $retval['conds']['pa.page_title'] = $title;
 100                 }
 101
 102                 return $retval;
 103         }
 104
 105         public function getQueryInfo() {
 106                 return $this->reallyGetQueryInfo();
 107         }
 108
 109         function getOrderFields() {
 110                 return [ 'ra.rd_namespace', 'ra.rd_title' ];
 111         }
 112
 113         /**
 114          * @param Skin $skin
 115          * @param object $result Result row
 116          * @return string
 117          */
 118         function formatResult( $skin, $result ) {
 119                 // If no Title B or C is in the query, it means this came from
 120                 // querycache (which only saves the 3 columns for title A).
 121                 // That does save the bulk of the query cost, but now we need to
 122                 // get a little more detail about each individual entry quickly
 123                 // using the filter of reallyGetQueryInfo.
 124                 $deep = false;
 125                 if ( $result ) {
 126                         if ( isset( $result->b_namespace ) ) {
 127                                 $deep = $result;
 128                         } else {
 129                                 $dbr = wfGetDB( DB_REPLICA );
 130                                 $qi = $this->reallyGetQueryInfo(
 131                                         $result->namespace,
 132                                         $result->title
 133                                 );
 134                                 $res = $dbr->select(
 135                                         $qi['tables'],
 136                                         $qi['fields'],
 137                                         $qi['conds'],
 138                                         __METHOD__
 139                                 );
 140
 141                                 if ( $res ) {
 142                                         $deep = $dbr->fetchObject( $res ) ?: false;
 143                                 }
 144                         }
 145                 }
 146
 147                 $titleA = Title::makeTitle( $result->namespace, $result->title );
 148
 149                 $linkRenderer = $this->getLinkRenderer();
 150                 if ( !$deep ) {
 151                         return '<del>' . $linkRenderer->makeLink( $titleA, null, [], [ 'redirect' => 'no' ] ) . '</del>';
 152                 }
 153
 154                 // if the page is editable, add an edit link
 155                 if (
 156                         // check user permissions
 157                         $this->getUser()->isAllowed( 'edit' ) &&
 158                         // check, if the content model is editable through action=edit
 159                         ContentHandler::getForTitle( $titleA )->supportsDirectEditing()
 160                 ) {
 161                         $edit = $linkRenderer->makeKnownLink(
 162                                 $titleA,
 163                                 $this->msg( 'parentheses', $this->msg( 'editlink' )->text() )->text(),
 164                                 [],
 165                                 [ 'action' => 'edit' ]
 166                         );
 167                 } else {
 168                         $edit = '';
 169                 }
 170
 171                 $linkA = $linkRenderer->makeKnownLink(
 172                         $titleA,
 173                         null,
 174                         [],
 175                         [ 'redirect' => 'no' ]
 176                 );
 177
 178                 $titleB = Title::makeTitle( $deep->b_namespace, $deep->b_title );
 179                 $linkB = $linkRenderer->makeKnownLink(
 180                         $titleB,
 181                         null,
 182                         [],
 183                         [ 'redirect' => 'no' ]
 184                 );
 185
 186                 $titleC = Title::makeTitle(
 187                         $deep->c_namespace,
 188                         $deep->c_title,
 189                         $deep->c_fragment,
 190                         $deep->c_interwiki
 191                 );
 192                 $linkC = $linkRenderer->makeKnownLink( $titleC, $titleC->getFullText() );
 193
 194                 $lang = $this->getLanguage();
 195                 $arr = $lang->getArrow() . $lang->getDirMark();
 196
 197                 return ( "{$linkA} {$edit} {$arr} {$linkB} {$arr} {$linkC}" );
 198         }
 199
 200         /**
 201          * Cache page content model and gender distinction for performance
 202          *
 203          * @param IDatabase $db
 204          * @param IResultWrapper $res
 205          */
 206         function preprocessResults( $db, $res ) {
 207                 if ( !$res->numRows() ) {
 208                         return;
 209                 }
 210
 211                 $batch = new LinkBatch;
 212                 foreach ( $res as $row ) {
 213                         $batch->add( $row->namespace, $row->title );
 214                         if ( isset( $row->b_namespace ) ) {
 215                                 // lazy loaded when using cached results
 216                                 $batch->add( $row->b_namespace, $row->b_title );
 217                         }
 218                         if ( isset( $row->c_interwiki ) && !$row->c_interwiki ) {
 219                                 // lazy loaded when using cached result, not added when interwiki link
 220                                 $batch->add( $row->c_namespace, $row->c_title );
 221                         }
 222                 }
 223                 $batch->execute();
 224
 225                 // Back to start for display
 226                 $res->seek( 0 );
 227         }
 228
 229         protected function getGroupName() {
 230                 return 'maintenance';
 231         }
 232 }