Adds background job to cleanup all previews.

* A repair step that inserts a background job for each user
* Each background job will delete for 15 seconds if it takes longer we
reschedule. This is done so instances that don't use the system cron
won't time out.
* Added tests

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

lib/private/Repair.php

@@ -36,6 +36,7 @@
 use OC\Repair\Collation;
 use OC\Repair\DropOldJobs;
 use OC\Repair\MoveUpdaterStepFile;
+use OC\Repair\NC11\CleanPreviews;
 use OC\Repair\NC11\MoveAvatars;
 use OC\Repair\OldGroupMembershipShares;
 use OC\Repair\RemoveGetETagEntries;
@@ -155,6 +156,10 @@ public static function getRepairSteps() {
 				\OC::$server->getJobList(),
 				\OC::$server->getSystemConfig()
 			),
+			new CleanPreviews(
+				\OC::$server->getJobList(),
+				\OC::$server->getUserManager()
+			),
 		];
 	}
 

lib/private/Repair/NC11/CleanPreviews.php

@@ -0,0 +1,63 @@
+<?php
+/**
+ * @copyright 2016 Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OC\Repair\NC11;
+
+use OCP\BackgroundJob\IJobList;
+use OCP\IUser;
+use OCP\IUserManager;
+use OCP\Migration\IOutput;
+use OCP\Migration\IRepairStep;
+
+class CleanPreviews implements IRepairStep {
+
+	/** @var IJobList */
+	private $jobList;
+
+	/** @var IUserManager */
+	private $userManager;
+
+	/**
+	 * MoveAvatars constructor.
+	 *
+	 * @param IJobList $jobList
+	 * @param IUserManager $userManager
+	 */
+	public function __construct(IJobList $jobList,
+								IUserManager $userManager) {
+		$this->jobList = $jobList;
+		$this->userManager = $userManager;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getName() {
+		return 'Add preview cleanup background jobs';
+	}
+
+	public function run(IOutput $output) {
+		$this->userManager->callForSeenUsers(function(IUser $user) {
+			$this->jobList->add(CleanPreviewsBackgroundJob::class, ['uid' => $user->getUID()]);
+		});
+	}
+}

lib/private/Repair/NC11/CleanPreviewsBackgroundJob.php

@@ -0,0 +1,121 @@
+<?php
+/**
+ * @copyright 2016 Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OC\Repair\NC11;
+
+use OC\BackgroundJob\QueuedJob;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\Files\Folder;
+use OCP\Files\IRootFolder;
+use OCP\Files\NotFoundException;
+use OCP\Files\NotPermittedException;
+use OCP\ILogger;
+
+class CleanPreviewsBackgroundJob extends QueuedJob {
+	/** @var IRootFolder */
+	private $rootFolder;
+
+	/** @var ILogger */
+	private $logger;
+
+	/** @var IJobList */
+	private $jobList;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/**
+	 * CleanPreviewsBackgroundJob constructor.
+	 *
+	 * @param IRootFolder $rootFolder
+	 * @param ILogger $logger
+	 * @param IJobList $jobList
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(IRootFolder $rootFolder,
+								ILogger $logger,
+								IJobList $jobList,
+								ITimeFactory $timeFactory) {
+		$this->rootFolder = $rootFolder;
+		$this->logger = $logger;
+		$this->jobList = $jobList;
+		$this->timeFactory = $timeFactory;
+	}
+
+	public function run($arguments) {
+		$uid = $arguments['uid'];
+		$this->logger->info('Started preview cleanup for ' . $uid);
+		$empty = $this->cleanupPreviews($uid);
+
+		if (!$empty) {
+			$this->jobList->add(self::class, ['uid' => $uid]);
+			$this->logger->info('New preview cleanup scheduled for ' . $uid);
+		} else {
+			$this->logger->info('Preview cleanup done for ' . $uid);
+		}
+	}
+
+	/**
+	 * @param $uid
+	 * @return bool
+	 */
+	private function cleanupPreviews($uid) {
+		try {
+			$userFolder = $this->rootFolder->getUserFolder($uid);
+		} catch (NotFoundException $e) {
+			return true;
+		}
+
+		$userRoot = $userFolder->getParent();
+
+		try {
+			/** @var Folder $thumbnailFolder */
+			$thumbnailFolder = $userRoot->get('thumbnails');
+		} catch (NotFoundException $e) {
+			return true;
+		}
+
+		$thumbnails = $thumbnailFolder->getDirectoryListing();
+
+		$start = $this->timeFactory->getTime();
+		foreach ($thumbnails as $thumbnail) {
+			try {
+				$thumbnail->delete();
+			} catch (NotPermittedException $e) {
+				// Ignore
+			}
+
+			if (($this->timeFactory->getTime() - $start) > 15) {
+				return false;
+			}
+		}
+
+		try {
+			$thumbnailFolder->delete();
+		} catch (NotPermittedException $e) {
+			// Ignore
+		}
+
+		return true;
+	}
+}

lib/private/Server.php

@@ -73,6 +73,7 @@
 use OC\Mail\Mailer;
 use OC\Memcache\ArrayCache;
 use OC\Notification\Manager;
+use OC\Repair\NC11\CleanPreviewsBackgroundJob;
 use OC\RichObjectStrings\Validator;
 use OC\Security\Bruteforce\Throttler;
 use OC\Security\CertificateManager;
@@ -798,9 +799,20 @@ public function __construct($webRoot, \OC\Config $config) {
 				$c->getSystemConfig()
 			);
 		});
+
 		$this->registerService('LockdownManager', function (Server $c) {
 			return new LockdownManager();
 		});
+
+		/* To trick DI since we don't extend the DIContainer here */
+		$this->registerService(CleanPreviewsBackgroundJob::class, function (Server $c) {
+			return new CleanPreviewsBackgroundJob(
+				$c->getRootFolder(),
+				$c->getLogger(),
+				$c->getJobList(),
+				new TimeFactory()
+			);
+		});
 	}
 
 	/**