includes/job/DoubleRedirectJob.php

   1 <?php
   2 /**
   3  * Job to fix double redirects after moving a page.
   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 JobQueue
  22  */
  23
  24 /**
  25  * Job to fix double redirects after moving a page
  26  *
  27  * @ingroup JobQueue
  28  */
  29 class DoubleRedirectJob extends Job {
  30         var $reason, $redirTitle, $destTitleText;
  31
  32         /**
  33          * @var User
  34          */
  35         static $user;
  36
  37         /**
  38          * Insert jobs into the job queue to fix redirects to the given title
  39          * @param $reason String: the reason for the fix, see message "double-redirect-fixed-<reason>"
  40          * @param $redirTitle Title: the title which has changed, redirects pointing to this title are fixed
  41          * @param $destTitle bool Not used
  42          */
  43         public static function fixRedirects( $reason, $redirTitle, $destTitle = false ) {
  44                 # Need to use the master to get the redirect table updated in the same transaction
  45                 $dbw = wfGetDB( DB_MASTER );
  46                 $res = $dbw->select(
  47                         array( 'redirect', 'page' ),
  48                         array( 'page_namespace', 'page_title' ),
  49                         array(
  50                                 'page_id = rd_from',
  51                                 'rd_namespace' => $redirTitle->getNamespace(),
  52                                 'rd_title' => $redirTitle->getDBkey()
  53                         ), __METHOD__ );
  54                 if ( !$res->numRows() ) {
  55                         return;
  56                 }
  57                 $jobs = array();
  58                 foreach ( $res as $row ) {
  59                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
  60                         if ( !$title ) {
  61                                 continue;
  62                         }
  63
  64                         $jobs[] = new self( $title, array(
  65                                 'reason' => $reason,
  66                                 'redirTitle' => $redirTitle->getPrefixedDBkey() ) );
  67                         # Avoid excessive memory usage
  68                         if ( count( $jobs ) > 10000 ) {
  69                                 Job::batchInsert( $jobs );
  70                                 $jobs = array();
  71                         }
  72                 }
  73                 Job::batchInsert( $jobs );
  74         }
  75
  76         function __construct( $title, $params = false, $id = 0 ) {
  77                 parent::__construct( 'fixDoubleRedirect', $title, $params, $id );
  78                 $this->reason = $params['reason'];
  79                 $this->redirTitle = Title::newFromText( $params['redirTitle'] );
  80                 $this->destTitleText = !empty( $params['destTitle'] ) ? $params['destTitle'] : '';
  81         }
  82
  83         /**
  84          * @return bool
  85          */
  86         function run() {
  87                 if ( !$this->redirTitle ) {
  88                         $this->setLastError( 'Invalid title' );
  89                         return false;
  90                 }
  91
  92                 $targetRev = Revision::newFromTitle( $this->title );
  93                 if ( !$targetRev ) {
  94                         wfDebug( __METHOD__.": target redirect already deleted, ignoring\n" );
  95                         return true;
  96                 }
  97                 $text = $targetRev->getText();
  98                 $currentDest = Title::newFromRedirect( $text );
  99                 if ( !$currentDest || !$currentDest->equals( $this->redirTitle ) ) {
 100                         wfDebug( __METHOD__.": Redirect has changed since the job was queued\n" );
 101                         return true;
 102                 }
 103
 104                 # Check for a suppression tag (used e.g. in periodically archived discussions)
 105                 $mw = MagicWord::get( 'staticredirect' );
 106                 if ( $mw->match( $text ) ) {
 107                         wfDebug( __METHOD__.": skipping: suppressed with __STATICREDIRECT__\n" );
 108                         return true;
 109                 }
 110
 111                 # Find the current final destination
 112                 $newTitle = self::getFinalDestination( $this->redirTitle );
 113                 if ( !$newTitle ) {
 114                         wfDebug( __METHOD__.": skipping: single redirect, circular redirect or invalid redirect destination\n" );
 115                         return true;
 116                 }
 117                 if ( $newTitle->equals( $this->redirTitle ) ) {
 118                         # The redirect is already right, no need to change it
 119                         # This can happen if the page was moved back (say after vandalism)
 120                         wfDebug( __METHOD__.": skipping, already good\n" );
 121                 }
 122
 123                 # Preserve fragment (bug 14904)
 124                 $newTitle = Title::makeTitle( $newTitle->getNamespace(), $newTitle->getDBkey(),
 125                         $currentDest->getFragment() );
 126
 127                 # Fix the text
 128                 # Remember that redirect pages can have categories, templates, etc.,
 129                 # so the regex has to be fairly general
 130                 $newText = preg_replace( '/ \[ \[  [^\]]*  \] \] /x',
 131                         '[[' . $newTitle->getFullText() . ']]',
 132                         $text, 1 );
 133
 134                 if ( $newText === $text ) {
 135                         $this->setLastError( 'Text unchanged???' );
 136                         return false;
 137                 }
 138
 139                 # Save it
 140                 global $wgUser;
 141                 $oldUser = $wgUser;
 142                 $wgUser = $this->getUser();
 143                 $article = WikiPage::factory( $this->title );
 144                 $reason = wfMsgForContent( 'double-redirect-fixed-' . $this->reason,
 145                         $this->redirTitle->getPrefixedText(), $newTitle->getPrefixedText() );
 146                 $article->doEdit( $newText, $reason, EDIT_UPDATE | EDIT_SUPPRESS_RC, false, $this->getUser() );
 147                 $wgUser = $oldUser;
 148
 149                 return true;
 150         }
 151
 152         /**
 153          * Get the final destination of a redirect
 154          *
 155          * @param $title Title
 156          *
 157          * @return bool if the specified title is not a redirect, or if it is a circular redirect
 158          */
 159         public static function getFinalDestination( $title ) {
 160                 $dbw = wfGetDB( DB_MASTER );
 161
 162                 $seenTitles = array(); # Circular redirect check
 163                 $dest = false;
 164
 165                 while ( true ) {
 166                         $titleText = $title->getPrefixedDBkey();
 167                         if ( isset( $seenTitles[$titleText] ) ) {
 168                                 wfDebug( __METHOD__, "Circular redirect detected, aborting\n" );
 169                                 return false;
 170                         }
 171                         $seenTitles[$titleText] = true;
 172
 173                         $row = $dbw->selectRow(
 174                                 array( 'redirect', 'page' ),
 175                                 array( 'rd_namespace', 'rd_title' ),
 176                                 array(
 177                                         'rd_from=page_id',
 178                                         'page_namespace' => $title->getNamespace(),
 179                                         'page_title' => $title->getDBkey()
 180                                 ), __METHOD__ );
 181                         if ( !$row ) {
 182                                 # No redirect from here, chain terminates
 183                                 break;
 184                         } else {
 185                                 $dest = $title = Title::makeTitle( $row->rd_namespace, $row->rd_title );
 186                         }
 187                 }
 188                 return $dest;
 189         }
 190
 191         /**
 192          * Get a user object for doing edits, from a request-lifetime cache
 193          * @return User
 194          */
 195         function getUser() {
 196                 if ( !self::$user ) {
 197                         self::$user = User::newFromName( wfMsgForContent( 'double-redirect-fixer' ), false );
 198                         # FIXME: newFromName could return false on a badly configured wiki.
 199                         if ( !self::$user->isLoggedIn() ) {
 200                                 self::$user->addToDatabase();
 201                         }
 202                 }
 203                 return self::$user;
 204         }
 205 }
 206