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   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 string Reason for the change, 'maintenance' or 'move'. Suffix fo
  31       *    message key 'double-redirect-fixed-'.
  32       */
  33      private $reason;
  34  
  35      /** @var Title The title which has changed, redirects pointing to this
  36       *    title are fixed
  37       */
  38      private $redirTitle;
  39  
  40      /** @var User */
  41      private static $user;
  42  
  43      /**
  44       * Insert jobs into the job queue to fix redirects to the given title
  45       * @param string $reason The reason for the fix, see message
  46       *   "double-redirect-fixed-<reason>"
  47       * @param Title $redirTitle The title which has changed, redirects
  48       *   pointing to this title are fixed
  49       * @param bool $destTitle Not used
  50       */
  51  	public static function fixRedirects( $reason, $redirTitle, $destTitle = false ) {
  52          # Need to use the master to get the redirect table updated in the same transaction
  53          $dbw = wfGetDB( DB_MASTER );
  54          $res = $dbw->select(
  55              array( 'redirect', 'page' ),
  56              array( 'page_namespace', 'page_title' ),
  57              array(
  58                  'page_id = rd_from',
  59                  'rd_namespace' => $redirTitle->getNamespace(),
  60                  'rd_title' => $redirTitle->getDBkey()
  61              ), __METHOD__ );
  62          if ( !$res->numRows() ) {
  63              return;
  64          }
  65          $jobs = array();
  66          foreach ( $res as $row ) {
  67              $title = Title::makeTitle( $row->page_namespace, $row->page_title );
  68              if ( !$title ) {
  69                  continue;
  70              }
  71  
  72              $jobs[] = new self( $title, array(
  73                  'reason' => $reason,
  74                  'redirTitle' => $redirTitle->getPrefixedDBkey() ) );
  75              # Avoid excessive memory usage
  76              if ( count( $jobs ) > 10000 ) {
  77                  JobQueueGroup::singleton()->push( $jobs );
  78                  $jobs = array();
  79              }
  80          }
  81          JobQueueGroup::singleton()->push( $jobs );
  82      }
  83  
  84      /**
  85       * @param Title $title
  86       * @param array|bool $params
  87       */
  88  	function __construct( $title, $params = false ) {
  89          parent::__construct( 'fixDoubleRedirect', $title, $params );
  90          $this->reason = $params['reason'];
  91          $this->redirTitle = Title::newFromText( $params['redirTitle'] );
  92      }
  93  
  94      /**
  95       * @return bool
  96       */
  97  	function run() {
  98          if ( !$this->redirTitle ) {
  99              $this->setLastError( 'Invalid title' );
 100  
 101              return false;
 102          }
 103  
 104          $targetRev = Revision::newFromTitle( $this->title, false, Revision::READ_LATEST );
 105          if ( !$targetRev ) {
 106              wfDebug( __METHOD__ . ": target redirect already deleted, ignoring\n" );
 107  
 108              return true;
 109          }
 110          $content = $targetRev->getContent();
 111          $currentDest = $content ? $content->getRedirectTarget() : null;
 112          if ( !$currentDest || !$currentDest->equals( $this->redirTitle ) ) {
 113              wfDebug( __METHOD__ . ": Redirect has changed since the job was queued\n" );
 114  
 115              return true;
 116          }
 117  
 118          // Check for a suppression tag (used e.g. in periodically archived discussions)
 119          $mw = MagicWord::get( 'staticredirect' );
 120          if ( $content->matchMagicWord( $mw ) ) {
 121              wfDebug( __METHOD__ . ": skipping: suppressed with __STATICREDIRECT__\n" );
 122  
 123              return true;
 124          }
 125  
 126          // Find the current final destination
 127          $newTitle = self::getFinalDestination( $this->redirTitle );
 128          if ( !$newTitle ) {
 129              wfDebug( __METHOD__ .
 130                  ": skipping: single redirect, circular redirect or invalid redirect destination\n" );
 131  
 132              return true;
 133          }
 134          if ( $newTitle->equals( $this->redirTitle ) ) {
 135              // The redirect is already right, no need to change it
 136              // This can happen if the page was moved back (say after vandalism)
 137              wfDebug( __METHOD__ . " : skipping, already good\n" );
 138          }
 139  
 140          // Preserve fragment (bug 14904)
 141          $newTitle = Title::makeTitle( $newTitle->getNamespace(), $newTitle->getDBkey(),
 142              $currentDest->getFragment(), $newTitle->getInterwiki() );
 143  
 144          // Fix the text
 145          $newContent = $content->updateRedirect( $newTitle );
 146  
 147          if ( $newContent->equals( $content ) ) {
 148              $this->setLastError( 'Content unchanged???' );
 149  
 150              return false;
 151          }
 152  
 153          $user = $this->getUser();
 154          if ( !$user ) {
 155              $this->setLastError( 'Invalid user' );
 156  
 157              return false;
 158          }
 159  
 160          // Save it
 161          global $wgUser;
 162          $oldUser = $wgUser;
 163          $wgUser = $user;
 164          $article = WikiPage::factory( $this->title );
 165  
 166          // Messages: double-redirect-fixed-move, double-redirect-fixed-maintenance
 167          $reason = wfMessage( 'double-redirect-fixed-' . $this->reason,
 168              $this->redirTitle->getPrefixedText(), $newTitle->getPrefixedText()
 169          )->inContentLanguage()->text();
 170          $article->doEditContent( $newContent, $reason, EDIT_UPDATE | EDIT_SUPPRESS_RC, false, $user );
 171          $wgUser = $oldUser;
 172  
 173          return true;
 174      }
 175  
 176      /**
 177       * Get the final destination of a redirect
 178       *
 179       * @param Title $title
 180       *
 181       * @return bool If the specified title is not a redirect, or if it is a circular redirect
 182       */
 183  	public static function getFinalDestination( $title ) {
 184          $dbw = wfGetDB( DB_MASTER );
 185  
 186          // Circular redirect check
 187          $seenTitles = array();
 188          $dest = false;
 189  
 190          while ( true ) {
 191              $titleText = $title->getPrefixedDBkey();
 192              if ( isset( $seenTitles[$titleText] ) ) {
 193                  wfDebug( __METHOD__, "Circular redirect detected, aborting\n" );
 194  
 195                  return false;
 196              }
 197              $seenTitles[$titleText] = true;
 198  
 199              if ( $title->isExternal() ) {
 200                  // If the target is interwiki, we have to break early (bug 40352).
 201                  // Otherwise it will look up a row in the local page table
 202                  // with the namespace/page of the interwiki target which can cause
 203                  // unexpected results (e.g. X -> foo:Bar -> Bar -> .. )
 204                  break;
 205              }
 206  
 207              $row = $dbw->selectRow(
 208                  array( 'redirect', 'page' ),
 209                  array( 'rd_namespace', 'rd_title', 'rd_interwiki' ),
 210                  array(
 211                      'rd_from=page_id',
 212                      'page_namespace' => $title->getNamespace(),
 213                      'page_title' => $title->getDBkey()
 214                  ), __METHOD__ );
 215              if ( !$row ) {
 216                  # No redirect from here, chain terminates
 217                  break;
 218              } else {
 219                  $dest = $title = Title::makeTitle(
 220                      $row->rd_namespace,
 221                      $row->rd_title,
 222                      '',
 223                      $row->rd_interwiki
 224                  );
 225              }
 226          }
 227  
 228          return $dest;
 229      }
 230  
 231      /**
 232       * Get a user object for doing edits, from a request-lifetime cache
 233       * False will be returned if the user name specified in the
 234       * 'double-redirect-fixer' message is invalid.
 235       *
 236       * @return User|bool
 237       */
 238  	function getUser() {
 239          if ( !self::$user ) {
 240              $username = wfMessage( 'double-redirect-fixer' )->inContentLanguage()->text();
 241              self::$user = User::newFromName( $username );
 242              # User::newFromName() can return false on a badly configured wiki.
 243              if ( self::$user && !self::$user->isLoggedIn() ) {
 244                  self::$user->addToDatabase();
 245              }
 246          }
 247  
 248          return self::$user;
 249      }
 250  }