includes/jobqueue/jobs/NullJob.php

   1 <?php
   2 /**
   3  * Degenerate job that does nothing.
   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 Cache
  22  */
  23
  24 /**
  25  * Degenerate job that does nothing, but can optionally replace itself
  26  * in the queue and/or sleep for a brief time period. These can be used
  27  * to represent "no-op" jobs or test lock contention and performance.
  28  *
  29  * @par Example:
  30  * Inserting a null job in the configured job queue:
  31  * @code
  32  * $ php maintenance/eval.php
  33  * > $queue = JobQueueGroup::singleton();
  34  * > $job = new NullJob( Title::newMainPage(), array( 'lives' => 10 ) );
  35  * > $queue->push( $job );
  36  * @endcode
  37  * You can then confirm the job has been enqueued by using the showJobs.php
  38  * maintenance utility:
  39  * @code
  40  * $ php maintenance/showJobs.php --group
  41  * null: 1 queue; 0 claimed (0 active, 0 abandoned)
  42  * $
  43  * @endcode
  44  *
  45  * @ingroup JobQueue
  46  */
  47 class NullJob extends Job {
  48         /**
  49          * @param Title $title
  50          * @param array $params Job parameters (lives, usleep)
  51          */
  52         function __construct( $title, $params ) {
  53                 parent::__construct( 'null', $title, $params );
  54                 if ( !isset( $this->params['lives'] ) ) {
  55                         $this->params['lives'] = 1;
  56                 }
  57                 if ( !isset( $this->params['usleep'] ) ) {
  58                         $this->params['usleep'] = 0;
  59                 }
  60                 $this->removeDuplicates = !empty( $this->params['removeDuplicates'] );
  61         }
  62
  63         public function run() {
  64                 if ( $this->params['usleep'] > 0 ) {
  65                         usleep( $this->params['usleep'] );
  66                 }
  67                 if ( $this->params['lives'] > 1 ) {
  68                         $params = $this->params;
  69                         $params['lives']--;
  70                         $job = new self( $this->title, $params );
  71                         JobQueueGroup::singleton()->push( $job );
  72                 }
  73
  74                 return true;
  75         }
  76 }