Automatically deduplicate root jobs on insertion

* This makes lazyPush() simple to use in more cases

Change-Id: I22e74485eaf3120e5669c5ee55dc7ab7310d7300

includes/deferred/HTMLCacheUpdate.php

@@ -56,7 +56,6 @@ class HTMLCacheUpdate implements DeferrableUpdate {
 		$count = $this->mTitle->getBacklinkCache()->getNumLinks( $this->mTable, 100 );
 		if ( $count >= 100 ) { // many backlinks
 			JobQueueGroup::singleton()->lazyPush( $job );
-			JobQueueGroup::singleton()->deduplicateRootJob( $job );
 		} else { // few backlinks ($count might be off even if 0)
 			$dbw = wfGetDB( DB_MASTER );
 			$dbw->onTransactionIdle( function () use ( $job ) {

includes/deferred/LinksUpdate.php

@@ -267,7 +267,6 @@ class LinksUpdate extends SqlDataUpdate {
 			);
 
 			JobQueueGroup::singleton()->push( $job );
-			JobQueueGroup::singleton()->deduplicateRootJob( $job );
 		}
 	}
 

includes/jobqueue/Job.php

@@ -196,15 +196,27 @@ abstract class Job implements IJobSpecification {
 	}
 
 	/**
+	 * Get "root job" parameters for a task
+	 *
+	 * This is used to no-op redundant jobs, including child jobs of jobs,
+	 * as long as the children inherit the root job parameters. When a job
+	 * with root job parameters and "rootJobIsSelf" set is pushed, the
+	 * deduplicateRootJob() method is automatically called on it. If the
+	 * root job is only virtual and not actually pushed (e.g. the sub-jobs
+	 * are inserted directly), then call deduplicateRootJob() directly.
+	 *
 	 * @see JobQueue::deduplicateRootJob()
+	 *
 	 * @param string $key A key that identifies the task
 	 * @return array Map of:
+	 *   - rootJobIsSelf    : true
 	 *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 	 *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 	 * @since 1.21
 	 */
 	public static function newRootJobParams( $key ) {
 		return array(
+			'rootJobIsSelf'    => true,
 			'rootJobSignature' => sha1( $key ),
 			'rootJobTimestamp' => wfTimestampNow()
 		);
@@ -236,6 +248,14 @@ abstract class Job implements IJobSpecification {
 			&& isset( $this->params['rootJobTimestamp'] );
 	}
 
+	/**
+	 * @see JobQueue::deduplicateRootJob()
+	 * @return bool Whether this is job is a root job
+	 */
+	public function isRootJob() {
+		return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
+	}
+
 	/**
 	 * Insert a single job into the queue.
 	 * @return bool True on success

includes/jobqueue/JobQueue.php

@@ -323,6 +323,12 @@ abstract class JobQueue {
 
 		$this->doBatchPush( $jobs, $flags );
 		$this->aggr->notifyQueueNonEmpty( $this->wiki, $this->type );
+
+		foreach ( $jobs as $job ) {
+			if ( $job->isRootJob() ) {
+				$this->deduplicateRootJob( $job );
+			}
+		}
 	}
 
 	/**

includes/jobqueue/JobSpecification.php

@@ -72,6 +72,12 @@ interface IJobSpecification {
 	 */
 	public function hasRootJobParams();
 
+	/**
+	 * @see JobQueue::deduplicateRootJob()
+	 * @return bool Whether this is job is a root job
+	 */
+	public function isRootJob();
+
 	/**
 	 * @return Title Descriptive title (this can simply be informative)
 	 */
@@ -195,6 +201,10 @@ class JobSpecification implements IJobSpecification {
 			&& isset( $this->params['rootJobTimestamp'] );
 	}
 
+	public function isRootJob() {
+		return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
+	}
+
 	/**
 	 * @return array Field/value map that can immediately be serialized
 	 * @since 1.25