includes/JobQueue.php

   1 <?php
   2
   3 if ( !defined( 'MEDIAWIKI' ) ) {
   4         die( "This file is part of MediaWiki, it is not a valid entry point\n" );
   5 }
   6
   7 class Job {
   8         var $command,
   9                 $title,
  10                 $params,
  11                 $removeDuplicates,
  12                 $error;
  13
  14         /*-------------------------------------------------------------------------
  15          * Static functions
  16          *------------------------------------------------------------------------*/
  17         /**
  18          * Add an array of refreshLinks jobs to the queue
  19          * @param array $titles Array of title objects.
  20          * @static
  21          */
  22         function queueLinksJobs( $titles ) {
  23                 $fname = 'Job::queueLinksJobs';
  24                 wfProfileIn( $fname );
  25                 foreach ( $titles as $title ) {
  26                         $job = new Job( 'refreshLinks', $title );
  27                         $job->insert();
  28                 }
  29                 wfProfileOut( $fname );
  30         }
  31
  32         /**
  33          * Pop a job off the front of the queue
  34          * @static
  35          * @return Job or false if there's no jobs
  36          */
  37         function pop() {
  38                 $fname = 'Job::pop';
  39                 wfProfileIn( $fname );
  40
  41                 // First check to see if there are any jobs in the slave DB
  42                 $dbr =& wfGetDB( DB_SLAVE );
  43                 $id = $dbr->selectField( 'job', 'job_id', '', $fname, array( 'LIMIT' => 1 ) );
  44                 if ( $id === false ) {
  45                         wfProfileOut( $fname );
  46                         return false;
  47                 }
  48
  49                 // Pop an item off the front of the queue
  50                 // Method due to Domas, may not work on all DBMSes
  51                 $dbw =& wfGetDB( DB_MASTER );
  52                 $jobTable = $dbw->tableName( 'job' );
  53                 $dbw->query( "DELETE FROM $jobTable WHERE " .
  54                         '(job_cmd = @job_cmd := job_cmd) AND ' .
  55                         '(job_namespace = @job_namespace := job_namespace) AND ' .
  56                         '(job_title = @job_title := job_title) AND ' .
  57                         '(job_params = @job_params := job_params) ' .
  58                         'LIMIT 1', $fname );
  59                 $affected = $dbw->affectedRows();
  60                 // Commit now before 100 other threads pile up behind us
  61                 $dbw->immediateCommit();
  62                 if ( !$affected ) {
  63                         wfProfileOut( $fname );
  64                         return false;
  65                 }
  66
  67                 $res = $dbw->query( "SELECT @job_cmd, @job_namespace, @job_title, @job_params", $fname );
  68                 $row = $dbw->fetchRow( $res );
  69                 if ( !$row ) {
  70                         wfProfileOut( $fname );
  71                         return false;
  72                 }
  73
  74                 $command = $row['@job_cmd'];
  75                 $namespace = $row['@job_namespace'];
  76                 $dbkey = $row['@job_title'];
  77                 $title = Title::makeTitleSafe( $namespace, $dbkey );
  78                 $params = $row['@job_params'];
  79                 $job = new Job( $command, $title, $params );
  80                 wfProfileOut( $fname );
  81                 return $job;
  82         }
  83
  84         /*-------------------------------------------------------------------------
  85          * Non-static functions
  86          *------------------------------------------------------------------------*/
  87
  88         function Job( $command, $title, $params = '' ) {
  89                 $this->command = $command;
  90                 $this->title = $title;
  91                 $this->params = $params;
  92
  93                 // A bit of premature generalisation
  94                 // Oh well, the whole class is premature generalisation really
  95                 $this->removeDuplicates = true;
  96         }
  97
  98         function insert() {
  99                 $fname = 'Job::insert';
 100
 101                 $fields = array(
 102                         'job_cmd' => $this->command,
 103                         'job_namespace' => $this->title->getNamespace(),
 104                         'job_title' => $this->title->getDBkey(),
 105                         'job_params' => $this->params
 106                 );
 107
 108                 $dbw =& wfGetDB( DB_MASTER );
 109
 110                 if ( $this->removeDuplicates ) {
 111                         $dbw->delete( 'job', $fields, $fname );
 112                 }
 113                 $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
 114                 $dbw->insert( 'job', $fields, $fname );
 115         }
 116
 117         /**
 118          * Run the job
 119          * @return boolean success
 120          */
 121         function run() {
 122                 $fname = 'Job::run';
 123                 wfProfileIn( $fname );
 124                 switch ( $this->command ) {
 125                         case 'refreshLinks':
 126                                 $retval = $this->refreshLinks();
 127                                 break;
 128                         default:
 129                                 $this->error = "Invalid job type {$this->command}, ignoring";
 130                                 wfDebug( $this->error . "\n" );
 131                                 $retval = false;
 132                 }
 133                 wfProfileOut( $fname );
 134                 return $retval;
 135         }
 136
 137         /**
 138          * Run a refreshLinks job
 139          * @return boolean success
 140          */
 141         function refreshLinks() {
 142                 global $wgParser;
 143
 144                 $dbw =& wfGetDB( DB_MASTER );
 145
 146                 $linkCache =& LinkCache::singleton();
 147                 $linkCache->clear();
 148
 149                 if ( is_null( $this->title ) ) {
 150                         $this->error = "refreshLinks: Invalid title";
 151                         return false;
 152                 }
 153
 154                 $revision = Revision::newFromTitle( $this->title );
 155                 if ( !$revision ) {
 156                         $this->error = 'refreshLinks: Article not found "' . $this->title->getPrefixedDBkey() . '"';
 157                         return false;
 158                 }
 159
 160                 $options = new ParserOptions;
 161                 $parserOutput = $wgParser->parse( $revision->getText(), $this->title, $options, true, true, $revision->getId() );
 162                 $update = new LinksUpdate( $this->title, $parserOutput );
 163                 $update->doUpdate();
 164                 return true;
 165         }
 166
 167         function toString() {
 168                 if ( is_object( $this->title ) ) {
 169                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 170                         if ( $this->params !== '' ) {
 171                                 $s .= ', ' . $this->params;
 172                         }
 173                         return $s;
 174                 } else {
 175                         return "{$this->command} {$this->params}";
 176                 }
 177         }
 178
 179         function getLastError() {
 180                 return $this->error;
 181         }
 182 }