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\ResultWrapper;
  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                                 'value' => 'pa.page_title',
  68
  69                                 'nsb' => 'pb.page_namespace',
  70                                 'tb' => 'pb.page_title',
  71
  72                                 // Select fields from redirect instead of page. Because there may
  73                                 // not actually be a page table row for this target (e.g. for interwiki redirects)
  74                                 'nsc' => 'rb.rd_namespace',
  75                                 'tc' => 'rb.rd_title',
  76                                 'fc' => 'rb.rd_fragment',
  77                                 'iwc' => 'rb.rd_interwiki',
  78                         ],
  79                         'conds' => [
  80                                 'ra.rd_from = pa.page_id',
  81
  82                                 // Filter out redirects where the target goes interwiki (T42353).
  83                                 // This isn't an optimization, it is required for correct results,
  84                                 // otherwise a non-double redirect like Bar -> w:Foo will show up
  85                                 // like "Bar -> Foo -> w:Foo".
  86
  87                                 // Need to check both NULL and "" for some reason,
  88                                 // apparently either can be stored for non-iw entries.
  89                                 'ra.rd_interwiki IS NULL OR ra.rd_interwiki = ' . $dbr->addQuotes( '' ),
  90
  91                                 'pb.page_namespace = ra.rd_namespace',
  92                                 'pb.page_title = ra.rd_title',
  93
  94                                 'rb.rd_from = pb.page_id',
  95                         ]
  96                 ];
  97
  98                 if ( $limitToTitle ) {
  99                         $retval['conds']['pa.page_namespace'] = $namespace;
 100                         $retval['conds']['pa.page_title'] = $title;
 101                 }
 102
 103                 return $retval;
 104         }
 105
 106         public function getQueryInfo() {
 107                 return $this->reallyGetQueryInfo();
 108         }
 109
 110         function getOrderFields() {
 111                 return [ 'ra.rd_namespace', 'ra.rd_title' ];
 112         }
 113
 114         /**
 115          * @param Skin $skin
 116          * @param object $result Result row
 117          * @return string
 118          */
 119         function formatResult( $skin, $result ) {
 120                 $titleA = Title::makeTitle( $result->namespace, $result->title );
 121
 122                 // If only titleA is in the query, it means this came from
 123                 // querycache (which only saves 3 columns).
 124                 // That does save the bulk of the query cost, but now we need to
 125                 // get a little more detail about each individual entry quickly
 126                 // using the filter of reallyGetQueryInfo.
 127                 if ( $result && !isset( $result->nsb ) ) {
 128                         $dbr = wfGetDB( DB_REPLICA );
 129                         $qi = $this->reallyGetQueryInfo(
 130                                 $result->namespace,
 131                                 $result->title
 132                         );
 133                         $res = $dbr->select(
 134                                 $qi['tables'],
 135                                 $qi['fields'],
 136                                 $qi['conds'],
 137                                 __METHOD__
 138                         );
 139
 140                         if ( $res ) {
 141                                 $result = $dbr->fetchObject( $res );
 142                         }
 143                 }
 144                 $linkRenderer = $this->getLinkRenderer();
 145                 if ( !$result ) {
 146                         return '<del>' . $linkRenderer->makeLink( $titleA, null, [], [ 'redirect' => 'no' ] ) . '</del>';
 147                 }
 148
 149                 $titleB = Title::makeTitle( $result->nsb, $result->tb );
 150                 $titleC = Title::makeTitle( $result->nsc, $result->tc, $result->fc, $result->iwc );
 151
 152                 $linkA = $linkRenderer->makeKnownLink(
 153                         $titleA,
 154                         null,
 155                         [],
 156                         [ 'redirect' => 'no' ]
 157                 );
 158
 159                 // if the page is editable, add an edit link
 160                 if (
 161                         // check user permissions
 162                         $this->getUser()->isAllowed( 'edit' ) &&
 163                         // check, if the content model is editable through action=edit
 164                         ContentHandler::getForTitle( $titleA )->supportsDirectEditing()
 165                 ) {
 166                         $edit = $linkRenderer->makeKnownLink(
 167                                 $titleA,
 168                                 $this->msg( 'parentheses', $this->msg( 'editlink' )->text() )->text(),
 169                                 [],
 170                                 [ 'action' => 'edit' ]
 171                         );
 172                 } else {
 173                         $edit = '';
 174                 }
 175
 176                 $linkB = $linkRenderer->makeKnownLink(
 177                         $titleB,
 178                         null,
 179                         [],
 180                         [ 'redirect' => 'no' ]
 181                 );
 182
 183                 $linkC = $linkRenderer->makeKnownLink( $titleC, $titleC->getFullText() );
 184
 185                 $lang = $this->getLanguage();
 186                 $arr = $lang->getArrow() . $lang->getDirMark();
 187
 188                 return ( "{$linkA} {$edit} {$arr} {$linkB} {$arr} {$linkC}" );
 189         }
 190
 191         /**
 192          * Cache page content model and gender distinction for performance
 193          *
 194          * @param IDatabase $db
 195          * @param ResultWrapper $res
 196          */
 197         function preprocessResults( $db, $res ) {
 198                 if ( !$res->numRows() ) {
 199                         return;
 200                 }
 201
 202                 $batch = new LinkBatch;
 203                 foreach ( $res as $row ) {
 204                         $batch->add( $row->namespace, $row->title );
 205                         if ( isset( $row->nsb ) ) {
 206                                 // lazy loaded when using cached results
 207                                 $batch->add( $row->nsb, $row->tb );
 208                         }
 209                         if ( isset( $row->iwc ) && !$row->iwc ) {
 210                                 // lazy loaded when using cached result, not added when interwiki link
 211                                 $batch->add( $row->nsc, $row->tc );
 212                         }
 213                 }
 214                 $batch->execute();
 215
 216                 // Back to start for display
 217                 $res->seek( 0 );
 218         }
 219
 220         protected function getGroupName() {
 221                 return 'maintenance';
 222         }
 223 }