From fc332b275c4a0b216f9918d108e8e16d054815be Mon Sep 17 00:00:00 2001
From: =?utf8?q?Tim=20D=C3=BCsterhus?= <duesterhus@woltlab.com>
Date: Wed, 17 Jun 2015 21:53:09 +0200
Subject: [PATCH] Add BackgroundQueueHandler::enqueueIn() and rename enqueue()
 to enqueueAt()

This also disallows scheduling jobs for execution in the past to prevent
starving of jobs with a non-immediate execution (previous default parameter
of zero).
---
 .../BackgroundQueueHandler.class.php          | 21 +++++++++++++++++--
 .../BackgroundQueueCleanUpCronjob.class.php   |  2 +-
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/wcfsetup/install/files/lib/system/background/BackgroundQueueHandler.class.php b/wcfsetup/install/files/lib/system/background/BackgroundQueueHandler.class.php
index a1beb8adb7..00519189dc 100644
--- a/wcfsetup/install/files/lib/system/background/BackgroundQueueHandler.class.php
+++ b/wcfsetup/install/files/lib/system/background/BackgroundQueueHandler.class.php
@@ -2,6 +2,7 @@
 namespace wcf\system\background;
 use wcf\system\background\job\AbstractBackgroundJob;
 use wcf\system\exception\LoggedException;
+use wcf\system\exception\SystemException;
 use wcf\system\SingletonFactory;
 use wcf\system\WCF;
 
@@ -16,6 +17,18 @@ use wcf\system\WCF;
  * @category	Community Framework
  */
 class BackgroundQueueHandler extends SingletonFactory {
+	/**
+	 * Enqueues the given job for execution in the specified number of
+	 * seconds. Defaults to "as soon as possible" (0 seconds).
+	 * 
+	 * @param	\wcf\system\background\job\AbstractBackgroundJob	$job	The job to enqueue.
+	 * @param	int							$time	Minimum number of seconds to wait before performing the job.
+	 * @see	\wcf\system\background\BackgroundQueueHandler::enqueueAt()
+	 */
+	public function enqueueIn(AbstractBackgroundJob $job, $time = 0) {
+		return self::enqueueAt($job, TIME_NOW + $time);
+	}
+	
 	/**
 	 * Enqueues the given job for execution at the given time.
 	 * Note: The time is a minimum time. Depending on the size of
@@ -24,7 +37,11 @@ class BackgroundQueueHandler extends SingletonFactory {
 	 * @param	\wcf\system\background\job\AbstractBackgroundJob	$job	The job to enqueue.
 	 * @param	int							$time	Earliest time to consider the job for execution.
 	 */
-	public function enqueue(AbstractBackgroundJob $job, $time = 0) {
+	public function enqueueAt(AbstractBackgroundJob $job, $time) {
+		if ($time < TIME_NOW) {
+			throw new SystemException("You may not schedule a job in the past (".$time." is smaller than the current timestamp ".TIME_NOW.").");
+		}
+		
 		$sql = "INSERT INTO	wcf".WCF_N."_background_job
 					(job, time)
 			VALUES		(?, ?)";
@@ -55,7 +72,7 @@ class BackgroundQueueHandler extends SingletonFactory {
 			$job->fail();
 			
 			if ($job->getFailures() <= $job::MAX_FAILURES) {
-				$this->enqueue($job, TIME_NOW + $job->retryAfter());
+				$this->enqueueIn($job, $job->retryAfter());
 			}
 			else {
 				// job failed too often: log
diff --git a/wcfsetup/install/files/lib/system/cronjob/BackgroundQueueCleanUpCronjob.class.php b/wcfsetup/install/files/lib/system/cronjob/BackgroundQueueCleanUpCronjob.class.php
index 657ff2befc..d19dfd34af 100644
--- a/wcfsetup/install/files/lib/system/cronjob/BackgroundQueueCleanUpCronjob.class.php
+++ b/wcfsetup/install/files/lib/system/cronjob/BackgroundQueueCleanUpCronjob.class.php
@@ -48,7 +48,7 @@ class BackgroundQueueCleanUpCronjob extends AbstractCronjob {
 						$job->fail();
 						
 						if ($job->getFailures() <= $job::MAX_FAILURES) {
-							BackgroundQueueHandler::getInstance()->enqueue($job, TIME_NOW + $job->retryAfter());
+							BackgroundQueueHandler::getInstance()->enqueueIn($job, $job->retryAfter());
 						}
 					}
 				}
-- 
2.20.1