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   1  <?php
   2  /**
   3   * Job queue aggregator code.
   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   * @author Aaron Schulz
  22   */
  23  
  24  /**
  25   * Class to handle tracking information about all queues
  26   *
  27   * @ingroup JobQueue
  28   * @since 1.21
  29   */
  30  abstract class JobQueueAggregator {
  31      /** @var JobQueueAggregator */
  32      protected static $instance = null;
  33  
  34      /**
  35       * @param array $params
  36       */
  37  	protected function __construct( array $params ) {
  38      }
  39  
  40      /**
  41       * @throws MWException
  42       * @return JobQueueAggregator
  43       */
  44  	final public static function singleton() {
  45          global $wgJobQueueAggregator;
  46  
  47          if ( !isset( self::$instance ) ) {
  48              $class = $wgJobQueueAggregator['class'];
  49              $obj = new $class( $wgJobQueueAggregator );
  50              if ( !( $obj instanceof JobQueueAggregator ) ) {
  51                  throw new MWException( "Class '$class' is not a JobQueueAggregator class." );
  52              }
  53              self::$instance = $obj;
  54          }
  55  
  56          return self::$instance;
  57      }
  58  
  59      /**
  60       * Destroy the singleton instance
  61       *
  62       * @return void
  63       */
  64  	final public static function destroySingleton() {
  65          self::$instance = null;
  66      }
  67  
  68      /**
  69       * Mark a queue as being empty
  70       *
  71       * @param string $wiki
  72       * @param string $type
  73       * @return bool Success
  74       */
  75  	final public function notifyQueueEmpty( $wiki, $type ) {
  76          wfProfileIn( __METHOD__ );
  77          $ok = $this->doNotifyQueueEmpty( $wiki, $type );
  78          wfProfileOut( __METHOD__ );
  79  
  80          return $ok;
  81      }
  82  
  83      /**
  84       * @see JobQueueAggregator::notifyQueueEmpty()
  85       */
  86      abstract protected function doNotifyQueueEmpty( $wiki, $type );
  87  
  88      /**
  89       * Mark a queue as being non-empty
  90       *
  91       * @param string $wiki
  92       * @param string $type
  93       * @return bool Success
  94       */
  95  	final public function notifyQueueNonEmpty( $wiki, $type ) {
  96          wfProfileIn( __METHOD__ );
  97          $ok = $this->doNotifyQueueNonEmpty( $wiki, $type );
  98          wfProfileOut( __METHOD__ );
  99  
 100          return $ok;
 101      }
 102  
 103      /**
 104       * @see JobQueueAggregator::notifyQueueNonEmpty()
 105       */
 106      abstract protected function doNotifyQueueNonEmpty( $wiki, $type );
 107  
 108      /**
 109       * Get the list of all of the queues with jobs
 110       *
 111       * @return array (job type => (list of wiki IDs))
 112       */
 113  	final public function getAllReadyWikiQueues() {
 114          wfProfileIn( __METHOD__ );
 115          $res = $this->doGetAllReadyWikiQueues();
 116          wfProfileOut( __METHOD__ );
 117  
 118          return $res;
 119      }
 120  
 121      /**
 122       * @see JobQueueAggregator::getAllReadyWikiQueues()
 123       */
 124      abstract protected function doGetAllReadyWikiQueues();
 125  
 126      /**
 127       * Purge all of the aggregator information
 128       *
 129       * @return bool Success
 130       */
 131  	final public function purge() {
 132          wfProfileIn( __METHOD__ );
 133          $res = $this->doPurge();
 134          wfProfileOut( __METHOD__ );
 135  
 136          return $res;
 137      }
 138  
 139      /**
 140       * @see JobQueueAggregator::purge()
 141       */
 142      abstract protected function doPurge();
 143  
 144      /**
 145       * Get all databases that have a pending job.
 146       * This poll all the queues and is this expensive.
 147       *
 148       * @return array (job type => (list of wiki IDs))
 149       */
 150  	protected function findPendingWikiQueues() {
 151          global $wgLocalDatabases;
 152  
 153          $pendingDBs = array(); // (job type => (db list))
 154          foreach ( $wgLocalDatabases as $db ) {
 155              foreach ( JobQueueGroup::singleton( $db )->getQueuesWithJobs() as $type ) {
 156                  $pendingDBs[$type][] = $db;
 157              }
 158          }
 159  
 160          return $pendingDBs;
 161      }
 162  }