diff options
Diffstat (limited to 'includes/JobQueue.php')
| -rw-r--r-- | includes/JobQueue.php | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/includes/JobQueue.php b/includes/JobQueue.php new file mode 100644 index 00000000..746cf5de --- /dev/null +++ b/includes/JobQueue.php @@ -0,0 +1,267 @@ +<?php + +if ( !defined( 'MEDIAWIKI' ) ) { + die( "This file is part of MediaWiki, it is not a valid entry point\n" ); +} + +abstract class Job { + var $command, + $title, + $params, + $id, + $removeDuplicates, + $error; + + /*------------------------------------------------------------------------- + * Static functions + *------------------------------------------------------------------------*/ + + /** + * @deprecated use LinksUpdate::queueRecursiveJobs() + */ + /** + * static function queueLinksJobs( $titles ) {} + */ + + /** + * Pop a job off the front of the queue + * @static + * @return Job or false if there's no jobs + */ + static function pop() { + wfProfileIn( __METHOD__ ); + + $dbr =& wfGetDB( DB_SLAVE ); + + // Get a job from the slave + $row = $dbr->selectRow( 'job', '*', '', __METHOD__, + array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ) + ); + + if ( $row === false ) { + wfProfileOut( __METHOD__ ); + return false; + } + + // Try to delete it from the master + $dbw =& wfGetDB( DB_MASTER ); + $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ ); + $affected = $dbw->affectedRows(); + $dbw->immediateCommit(); + + if ( !$affected ) { + // Failed, someone else beat us to it + // Try getting a random row + $row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob', + 'MAX(job_id) as maxjob' ), '', __METHOD__ ); + if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) { + // No jobs to get + wfProfileOut( __METHOD__ ); + return false; + } + // Get the random row + $row = $dbw->selectRow( 'job', '*', + array( 'job_id' => mt_rand( $row->minjob, $row->maxjob ) ), __METHOD__ ); + if ( $row === false ) { + // Random job gone before we got the chance to select it + // Give up + wfProfileOut( __METHOD__ ); + return false; + } + // Delete the random row + $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ ); + $affected = $dbw->affectedRows(); + $dbw->immediateCommit(); + + if ( !$affected ) { + // Random job gone before we exclusively deleted it + // Give up + wfProfileOut( __METHOD__ ); + return false; + } + } + + // If execution got to here, there's a row in $row that has been deleted from the database + // by this thread. Hence the concurrent pop was successful. + $namespace = $row->job_namespace; + $dbkey = $row->job_title; + $title = Title::makeTitleSafe( $namespace, $dbkey ); + $job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id ); + + // Remove any duplicates it may have later in the queue + $dbw->delete( 'job', $job->insertFields(), __METHOD__ ); + + wfProfileOut( __METHOD__ ); + return $job; + } + + /** + * Create an object of a subclass + */ + static function factory( $command, $title, $params = false, $id = 0 ) { + switch ( $command ) { + case 'refreshLinks': + return new RefreshLinksJob( $title, $params, $id ); + case 'htmlCacheUpdate': + case 'html_cache_update': # BC + return new HTMLCacheUpdateJob( $title, $params['table'], $params['start'], $params['end'], $id ); + default: + throw new MWException( "Invalid job command \"$command\"" ); + } + } + + static function makeBlob( $params ) { + if ( $params !== false ) { + return serialize( $params ); + } else { + return ''; + } + } + + static function extractBlob( $blob ) { + if ( (string)$blob !== '' ) { + return unserialize( $blob ); + } else { + return false; + } + } + + /*------------------------------------------------------------------------- + * Non-static functions + *------------------------------------------------------------------------*/ + + function __construct( $command, $title, $params = false, $id = 0 ) { + $this->command = $command; + $this->title = $title; + $this->params = $params; + $this->id = $id; + + // A bit of premature generalisation + // Oh well, the whole class is premature generalisation really + $this->removeDuplicates = true; + } + + /** + * Insert a single job into the queue. + */ + function insert() { + $fields = $this->insertFields(); + + $dbw =& wfGetDB( DB_MASTER ); + + if ( $this->removeDuplicates ) { + $res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__ ); + if ( $dbw->numRows( $res ) ) { + return; + } + } + $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' ); + $dbw->insert( 'job', $fields, __METHOD__ ); + } + + protected function insertFields() { + return array( + 'job_cmd' => $this->command, + 'job_namespace' => $this->title->getNamespace(), + 'job_title' => $this->title->getDBkey(), + 'job_params' => Job::makeBlob( $this->params ) + ); + } + + /** + * Batch-insert a group of jobs into the queue. + * This will be wrapped in a transaction with a forced commit. + * + * This may add duplicate at insert time, but they will be + * removed later on, when the first one is popped. + * + * @param $jobs array of Job objects + */ + static function batchInsert( $jobs ) { + if( count( $jobs ) ) { + $dbw = wfGetDB( DB_MASTER ); + $dbw->begin(); + foreach( $jobs as $job ) { + $rows[] = $job->insertFields(); + } + $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' ); + $dbw->commit(); + } + } + + /** + * Run the job + * @return boolean success + */ + abstract function run(); + + function toString() { + $paramString = ''; + if ( $this->params ) { + foreach ( $this->params as $key => $value ) { + if ( $paramString != '' ) { + $paramString .= ' '; + } + $paramString .= "$key=$value"; + } + } + + if ( is_object( $this->title ) ) { + $s = "{$this->command} " . $this->title->getPrefixedDBkey(); + if ( $paramString !== '' ) { + $s .= ' ' . $paramString; + } + return $s; + } else { + return "{$this->command} $paramString"; + } + } + + function getLastError() { + return $this->error; + } +} + +class RefreshLinksJob extends Job { + function __construct( $title, $params = '', $id = 0 ) { + parent::__construct( 'refreshLinks', $title, $params, $id ); + } + + /** + * Run a refreshLinks job + * @return boolean success + */ + function run() { + global $wgParser; + wfProfileIn( __METHOD__ ); + + $linkCache =& LinkCache::singleton(); + $linkCache->clear(); + + if ( is_null( $this->title ) ) { + $this->error = "refreshLinks: Invalid title"; + wfProfileOut( __METHOD__ ); + return false; + } + + $revision = Revision::newFromTitle( $this->title ); + if ( !$revision ) { + $this->error = 'refreshLinks: Article not found "' . $this->title->getPrefixedDBkey() . '"'; + wfProfileOut( __METHOD__ ); + return false; + } + + wfProfileIn( __METHOD__.'-parse' ); + $options = new ParserOptions; + $parserOutput = $wgParser->parse( $revision->getText(), $this->title, $options, true, true, $revision->getId() ); + wfProfileOut( __METHOD__.'-parse' ); + wfProfileIn( __METHOD__.'-update' ); + $update = new LinksUpdate( $this->title, $parserOutput, false ); + $update->doUpdate(); + wfProfileOut( __METHOD__.'-update' ); + wfProfileOut( __METHOD__ ); + return true; + } +} + +?> |