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 /**
  25  * A special page listing redirects to redirecting page.
  26  * The software will automatically not follow double redirects, to prevent loops.
  27  *
  28  * @ingroup SpecialPage
  29  */
  30 class DoubleRedirectsPage extends QueryPage {
  31
  32         function __construct( $name = 'DoubleRedirects' ) {
  33                 parent::__construct( $name );
  34         }
  35
  36         function isExpensive() {
  37                 return true;
  38         }
  39
  40         function isSyndicated() {
  41                 return false;
  42         }
  43
  44         function sortDescending() {
  45                 return false;
  46         }
  47
  48         function getPageHeader() {
  49                 return $this->msg( 'doubleredirectstext' )->parseAsBlock();
  50         }
  51
  52         function reallyGetQueryInfo( $namespace = null, $title = null ) {
  53                 $limitToTitle = !( $namespace === null && $title === null );
  54                 $retval = array (
  55                         'tables' => array (
  56                                 'ra' => 'redirect',
  57                                 'rb' => 'redirect',
  58                                 'pa' => 'page',
  59                                 'pb' => 'page'
  60                         ),
  61                         'fields' => array(
  62                                 'namespace' => 'pa.page_namespace',
  63                                 'title' => 'pa.page_title',
  64                                 'value' => 'pa.page_title',
  65
  66                                 'nsb' => 'pb.page_namespace',
  67                                 'tb' => 'pb.page_title',
  68
  69                                 // Select fields from redirect instead of page. Because there may
  70                                 // not actually be a page table row for this target (e.g. for interwiki redirects)
  71                                 'nsc' => 'rb.rd_namespace',
  72                                 'tc' => 'rb.rd_title',
  73                                 'iwc' => 'rb.rd_interwiki',
  74                         ),
  75                         'conds' => array(
  76                                 'ra.rd_from = pa.page_id',
  77
  78                                 // Filter out redirects where the target goes interwiki (bug 40353).
  79                                 // This isn't an optimization, it is required for correct results,
  80                                 // otherwise a non-double redirect like Bar -> w:Foo will show up
  81                                 // like "Bar -> Foo -> w:Foo".
  82
  83                                 // Need to check both NULL and "" for some reason,
  84                                 // apparently either can be stored for non-iw entries.
  85                                 '(ra.rd_interwiki IS NULL OR ra.rd_interwiki = "")',
  86
  87                                 'pb.page_namespace = ra.rd_namespace',
  88                                 'pb.page_title = ra.rd_title',
  89
  90                                 'rb.rd_from = pb.page_id',
  91                         )
  92                 );
  93                 if ( $limitToTitle ) {
  94                         $retval['conds']['pa.page_namespace'] = $namespace;
  95                         $retval['conds']['pa.page_title'] = $title;
  96                 }
  97                 return $retval;
  98         }
  99
 100         function getQueryInfo() {
 101                 return $this->reallyGetQueryInfo();
 102         }
 103
 104         function getOrderFields() {
 105                 return array ( 'ra.rd_namespace', 'ra.rd_title' );
 106         }
 107
 108         function formatResult( $skin, $result ) {
 109                 $titleA = Title::makeTitle( $result->namespace, $result->title );
 110
 111                 // If only titleA is in the query, it means this came from
 112                 // querycache (which only saves 3 columns).
 113                 // That does save the bulk of the query cost, but now we need to
 114                 // get a little more detail about each individual entry quickly
 115                 // using the filter of reallyGetQueryInfo.
 116                 if ( $result && !isset( $result->nsb ) ) {
 117                         $dbr = wfGetDB( DB_SLAVE );
 118                         $qi = $this->reallyGetQueryInfo( $result->namespace,
 119                                         $result->title );
 120                         $res = $dbr->select($qi['tables'], $qi['fields'],
 121                                         $qi['conds'], __METHOD__ );
 122                         if ( $res ) {
 123                                 $result = $dbr->fetchObject( $res );
 124                         }
 125                 }
 126                 if ( !$result ) {
 127                         return '<del>' . Linker::link( $titleA, null, array(), array( 'redirect' => 'no' ) ) . '</del>';
 128                 }
 129
 130                 $titleB = Title::makeTitle( $result->nsb, $result->tb );
 131                 $titleC = Title::makeTitle( $result->nsc, $result->tc, '',  $result->iwc );
 132
 133                 $linkA = Linker::linkKnown(
 134                         $titleA,
 135                         null,
 136                         array(),
 137                         array( 'redirect' => 'no' )
 138                 );
 139
 140                 $edit = Linker::linkKnown(
 141                         $titleA,
 142                         $this->msg( 'parentheses', $this->msg( 'editlink' )->text() )->escaped(),
 143                         array(),
 144                         array(
 145                                 'redirect' => 'no',
 146                                 'action' => 'edit'
 147                         )
 148                 );
 149
 150                 $linkB = Linker::linkKnown(
 151                         $titleB,
 152                         null,
 153                         array(),
 154                         array( 'redirect' => 'no' )
 155                 );
 156
 157                 $linkC = Linker::linkKnown( $titleC );
 158
 159                 $lang = $this->getLanguage();
 160                 $arr = $lang->getArrow() . $lang->getDirMark();
 161
 162                 return( "{$linkA} {$edit} {$arr} {$linkB} {$arr} {$linkC}" );
 163         }
 164 }