nextcloud / server

apps/files_versions/lib/Storage.php

Indentation +803 added lines, -803 removed lines

@@ -59,807 +59,807 @@
 use OCP\User;
 
 class Storage {
-	public const DEFAULTENABLED = true;
-	public const DEFAULTMAXSIZE = 50; // unit: percentage; 50% of available disk space/quota
-	public const VERSIONS_ROOT = 'files_versions/';
-
-	public const DELETE_TRIGGER_MASTER_REMOVED = 0;
-	public const DELETE_TRIGGER_RETENTION_CONSTRAINT = 1;
-	public const DELETE_TRIGGER_QUOTA_EXCEEDED = 2;
-
-	// files for which we can remove the versions after the delete operation was successful
-	private static $deletedFiles = [];
-
-	private static $sourcePathAndUser = [];
-
-	private static $max_versions_per_interval = [
-		//first 10sec, one version every 2sec
-		1 => ['intervalEndsAfter' => 10,      'step' => 2],
-		//next minute, one version every 10sec
-		2 => ['intervalEndsAfter' => 60,      'step' => 10],
-		//next hour, one version every minute
-		3 => ['intervalEndsAfter' => 3600,    'step' => 60],
-		//next 24h, one version every hour
-		4 => ['intervalEndsAfter' => 86400,   'step' => 3600],
-		//next 30days, one version per day
-		5 => ['intervalEndsAfter' => 2592000, 'step' => 86400],
-		//until the end one version per week
-		6 => ['intervalEndsAfter' => -1,      'step' => 604800],
-	];
-
-	/** @var \OCA\Files_Versions\AppInfo\Application */
-	private static $application;
-
-	/**
-	 * get the UID of the owner of the file and the path to the file relative to
-	 * owners files folder
-	 *
-	 * @param string $filename
-	 * @return array
-	 * @throws \OC\User\NoUserException
-	 */
-	public static function getUidAndFilename($filename) {
-		$uid = Filesystem::getOwner($filename);
-		$userManager = \OC::$server->getUserManager();
-		// if the user with the UID doesn't exists, e.g. because the UID points
-		// to a remote user with a federated cloud ID we use the current logged-in
-		// user. We need a valid local user to create the versions
-		if (!$userManager->userExists($uid)) {
-			$uid = User::getUser();
-		}
-		Filesystem::initMountPoints($uid);
-		if ($uid !== User::getUser()) {
-			$info = Filesystem::getFileInfo($filename);
-			$ownerView = new View('/'.$uid.'/files');
-			try {
-				$filename = $ownerView->getPath($info['fileid']);
-				// make sure that the file name doesn't end with a trailing slash
-				// can for example happen single files shared across servers
-				$filename = rtrim($filename, '/');
-			} catch (NotFoundException $e) {
-				$filename = null;
-			}
-		}
-		return [$uid, $filename];
-	}
-
-	/**
-	 * Remember the owner and the owner path of the source file
-	 *
-	 * @param string $source source path
-	 */
-	public static function setSourcePathAndUser($source) {
-		list($uid, $path) = self::getUidAndFilename($source);
-		self::$sourcePathAndUser[$source] = ['uid' => $uid, 'path' => $path];
-	}
-
-	/**
-	 * Gets the owner and the owner path from the source path
-	 *
-	 * @param string $source source path
-	 * @return array with user id and path
-	 */
-	public static function getSourcePathAndUser($source) {
-		if (isset(self::$sourcePathAndUser[$source])) {
-			$uid = self::$sourcePathAndUser[$source]['uid'];
-			$path = self::$sourcePathAndUser[$source]['path'];
-			unset(self::$sourcePathAndUser[$source]);
-		} else {
-			$uid = $path = false;
-		}
-		return [$uid, $path];
-	}
-
-	/**
-	 * get current size of all versions from a given user
-	 *
-	 * @param string $user user who owns the versions
-	 * @return int versions size
-	 */
-	private static function getVersionsSize($user) {
-		$view = new View('/' . $user);
-		$fileInfo = $view->getFileInfo('/files_versions');
-		return isset($fileInfo['size']) ? $fileInfo['size'] : 0;
-	}
-
-	/**
-	 * store a new version of a file.
-	 */
-	public static function store($filename) {
-
-		// if the file gets streamed we need to remove the .part extension
-		// to get the right target
-		$ext = pathinfo($filename, PATHINFO_EXTENSION);
-		if ($ext === 'part') {
-			$filename = substr($filename, 0, -5);
-		}
-
-		// we only handle existing files
-		if (! Filesystem::file_exists($filename) || Filesystem::is_dir($filename)) {
-			return false;
-		}
-
-		list($uid, $filename) = self::getUidAndFilename($filename);
-
-		$files_view = new View('/'.$uid .'/files');
-
-		$eventDispatcher = \OC::$server->getEventDispatcher();
-		$fileInfo = $files_view->getFileInfo($filename);
-		$id = $fileInfo->getId();
-		$nodes = \OC::$server->getRootFolder()->getUserFolder($uid)->getById($id);
-		foreach ($nodes as $node) {
-			$event = new CreateVersionEvent($node);
-			$eventDispatcher->dispatch('OCA\Files_Versions::createVersion', $event);
-			if ($event->shouldCreateVersion() === false) {
-				return false;
-			}
-		}
-
-		// no use making versions for empty files
-		if ($fileInfo->getSize() === 0) {
-			return false;
-		}
-
-		/** @var IVersionManager $versionManager */
-		$versionManager = \OC::$server->query(IVersionManager::class);
-		$userManager = \OC::$server->getUserManager();
-		$user = $userManager->get($uid);
-
-		$versionManager->createVersion($user, $fileInfo);
-	}
-
-
-	/**
-	 * mark file as deleted so that we can remove the versions if the file is gone
-	 * @param string $path
-	 */
-	public static function markDeletedFile($path) {
-		list($uid, $filename) = self::getUidAndFilename($path);
-		self::$deletedFiles[$path] = [
-			'uid' => $uid,
-			'filename' => $filename];
-	}
-
-	/**
-	 * delete the version from the storage and cache
-	 *
-	 * @param View $view
-	 * @param string $path
-	 */
-	protected static function deleteVersion($view, $path) {
-		$view->unlink($path);
-		/**
-		 * @var \OC\Files\Storage\Storage $storage
-		 * @var string $internalPath
-		 */
-		list($storage, $internalPath) = $view->resolvePath($path);
-		$cache = $storage->getCache($internalPath);
-		$cache->remove($internalPath);
-	}
-
-	/**
-	 * Delete versions of a file
-	 */
-	public static function delete($path) {
-		$deletedFile = self::$deletedFiles[$path];
-		$uid = $deletedFile['uid'];
-		$filename = $deletedFile['filename'];
-
-		if (!Filesystem::file_exists($path)) {
-			$view = new View('/' . $uid . '/files_versions');
-
-			$versions = self::getVersions($uid, $filename);
-			if (!empty($versions)) {
-				foreach ($versions as $v) {
-					\OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $path . $v['version'], 'trigger' => self::DELETE_TRIGGER_MASTER_REMOVED]);
-					self::deleteVersion($view, $filename . '.v' . $v['version']);
-					\OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $path . $v['version'], 'trigger' => self::DELETE_TRIGGER_MASTER_REMOVED]);
-				}
-			}
-		}
-		unset(self::$deletedFiles[$path]);
-	}
-
-	/**
-	 * Rename or copy versions of a file of the given paths
-	 *
-	 * @param string $sourcePath source path of the file to move, relative to
-	 * the currently logged in user's "files" folder
-	 * @param string $targetPath target path of the file to move, relative to
-	 * the currently logged in user's "files" folder
-	 * @param string $operation can be 'copy' or 'rename'
-	 */
-	public static function renameOrCopy($sourcePath, $targetPath, $operation) {
-		list($sourceOwner, $sourcePath) = self::getSourcePathAndUser($sourcePath);
-
-		// it was a upload of a existing file if no old path exists
-		// in this case the pre-hook already called the store method and we can
-		// stop here
-		if ($sourcePath === false) {
-			return true;
-		}
-
-		list($targetOwner, $targetPath) = self::getUidAndFilename($targetPath);
-
-		$sourcePath = ltrim($sourcePath, '/');
-		$targetPath = ltrim($targetPath, '/');
-
-		$rootView = new View('');
-
-		// did we move a directory ?
-		if ($rootView->is_dir('/' . $targetOwner . '/files/' . $targetPath)) {
-			// does the directory exists for versions too ?
-			if ($rootView->is_dir('/' . $sourceOwner . '/files_versions/' . $sourcePath)) {
-				// create missing dirs if necessary
-				self::createMissingDirectories($targetPath, new View('/'. $targetOwner));
-
-				// move the directory containing the versions
-				$rootView->$operation(
-					'/' . $sourceOwner . '/files_versions/' . $sourcePath,
-					'/' . $targetOwner . '/files_versions/' . $targetPath
-				);
-			}
-		} elseif ($versions = Storage::getVersions($sourceOwner, '/' . $sourcePath)) {
-			// create missing dirs if necessary
-			self::createMissingDirectories($targetPath, new View('/'. $targetOwner));
-
-			foreach ($versions as $v) {
-				// move each version one by one to the target directory
-				$rootView->$operation(
-					'/' . $sourceOwner . '/files_versions/' . $sourcePath.'.v' . $v['version'],
-					'/' . $targetOwner . '/files_versions/' . $targetPath.'.v'.$v['version']
-				);
-			}
-		}
-
-		// if we moved versions directly for a file, schedule expiration check for that file
-		if (!$rootView->is_dir('/' . $targetOwner . '/files/' . $targetPath)) {
-			self::scheduleExpire($targetOwner, $targetPath);
-		}
-	}
-
-	/**
-	 * Rollback to an old version of a file.
-	 *
-	 * @param string $file file name
-	 * @param int $revision revision timestamp
-	 * @return bool
-	 */
-	public static function rollback(string $file, int $revision, IUser $user) {
-
-		// add expected leading slash
-		$filename = '/' . ltrim($file, '/');
-
-		// Fetch the userfolder to trigger view hooks
-		$userFolder = \OC::$server->getUserFolder($user->getUID());
-
-		$users_view = new View('/'.$user->getUID());
-		$files_view = new View('/'. $user->getUID().'/files');
-
-		$versionCreated = false;
-
-		$fileInfo = $files_view->getFileInfo($file);
-
-		// check if user has the permissions to revert a version
-		if (!$fileInfo->isUpdateable()) {
-			return false;
-		}
-
-		//first create a new version
-		$version = 'files_versions'.$filename.'.v'.$users_view->filemtime('files'.$filename);
-		if (!$users_view->file_exists($version)) {
-			$users_view->copy('files'.$filename, 'files_versions'.$filename.'.v'.$users_view->filemtime('files'.$filename));
-			$versionCreated = true;
-		}
-
-		$fileToRestore = 'files_versions' . $filename . '.v' . $revision;
-
-		// Restore encrypted version of the old file for the newly restored file
-		// This has to happen manually here since the file is manually copied below
-		$oldVersion = $users_view->getFileInfo($fileToRestore)->getEncryptedVersion();
-		$oldFileInfo = $users_view->getFileInfo($fileToRestore);
-		$cache = $fileInfo->getStorage()->getCache();
-		$cache->update(
-			$fileInfo->getId(), [
-				'encrypted' => $oldVersion,
-				'encryptedVersion' => $oldVersion,
-				'size' => $oldFileInfo->getSize()
-			]
-		);
-
-		// rollback
-		if (self::copyFileContents($users_view, $fileToRestore, 'files' . $filename)) {
-			$files_view->touch($file, $revision);
-			Storage::scheduleExpire($user->getUID(), $file);
-
-			$node = $userFolder->get($file);
-
-			// TODO: move away from those legacy hooks!
-			\OC_Hook::emit('\OCP\Versions', 'rollback', [
-				'path' => $filename,
-				'revision' => $revision,
-				'node' => $node,
-			]);
-			return true;
-		} elseif ($versionCreated) {
-			self::deleteVersion($users_view, $version);
-		}
-
-		return false;
-	}
-
-	/**
-	 * Stream copy file contents from $path1 to $path2
-	 *
-	 * @param View $view view to use for copying
-	 * @param string $path1 source file to copy
-	 * @param string $path2 target file
-	 *
-	 * @return bool true for success, false otherwise
-	 */
-	private static function copyFileContents($view, $path1, $path2) {
-		/** @var \OC\Files\Storage\Storage $storage1 */
-		list($storage1, $internalPath1) = $view->resolvePath($path1);
-		/** @var \OC\Files\Storage\Storage $storage2 */
-		list($storage2, $internalPath2) = $view->resolvePath($path2);
-
-		$view->lockFile($path1, ILockingProvider::LOCK_EXCLUSIVE);
-		$view->lockFile($path2, ILockingProvider::LOCK_EXCLUSIVE);
-
-		// TODO add a proper way of overwriting a file while maintaining file ids
-		if ($storage1->instanceOfStorage('\OC\Files\ObjectStore\ObjectStoreStorage') || $storage2->instanceOfStorage('\OC\Files\ObjectStore\ObjectStoreStorage')) {
-			$source = $storage1->fopen($internalPath1, 'r');
-			$target = $storage2->fopen($internalPath2, 'w');
-			list(, $result) = \OC_Helper::streamCopy($source, $target);
-			fclose($source);
-			fclose($target);
-
-			if ($result !== false) {
-				$storage1->unlink($internalPath1);
-			}
-		} else {
-			$result = $storage2->moveFromStorage($storage1, $internalPath1, $internalPath2);
-		}
-
-		$view->unlockFile($path1, ILockingProvider::LOCK_EXCLUSIVE);
-		$view->unlockFile($path2, ILockingProvider::LOCK_EXCLUSIVE);
-
-		return ($result !== false);
-	}
-
-	/**
-	 * get a list of all available versions of a file in descending chronological order
-	 * @param string $uid user id from the owner of the file
-	 * @param string $filename file to find versions of, relative to the user files dir
-	 * @param string $userFullPath
-	 * @return array versions newest version first
-	 */
-	public static function getVersions($uid, $filename, $userFullPath = '') {
-		$versions = [];
-		if (empty($filename)) {
-			return $versions;
-		}
-		// fetch for old versions
-		$view = new View('/' . $uid . '/');
-
-		$pathinfo = pathinfo($filename);
-		$versionedFile = $pathinfo['basename'];
-
-		$dir = Filesystem::normalizePath(self::VERSIONS_ROOT . '/' . $pathinfo['dirname']);
-
-		$dirContent = false;
-		if ($view->is_dir($dir)) {
-			$dirContent = $view->opendir($dir);
-		}
-
-		if ($dirContent === false) {
-			return $versions;
-		}
-
-		if (is_resource($dirContent)) {
-			while (($entryName = readdir($dirContent)) !== false) {
-				if (!Filesystem::isIgnoredDir($entryName)) {
-					$pathparts = pathinfo($entryName);
-					$filename = $pathparts['filename'];
-					if ($filename === $versionedFile) {
-						$pathparts = pathinfo($entryName);
-						$timestamp = substr($pathparts['extension'], 1);
-						$filename = $pathparts['filename'];
-						$key = $timestamp . '#' . $filename;
-						$versions[$key]['version'] = $timestamp;
-						$versions[$key]['humanReadableTimestamp'] = self::getHumanReadableTimestamp($timestamp);
-						if (empty($userFullPath)) {
-							$versions[$key]['preview'] = '';
-						} else {
-							$versions[$key]['preview'] = \OC::$server->getURLGenerator('files_version.Preview.getPreview', ['file' => $userFullPath, 'version' => $timestamp]);
-						}
-						$versions[$key]['path'] = Filesystem::normalizePath($pathinfo['dirname'] . '/' . $filename);
-						$versions[$key]['name'] = $versionedFile;
-						$versions[$key]['size'] = $view->filesize($dir . '/' . $entryName);
-						$versions[$key]['mimetype'] = \OC::$server->getMimeTypeDetector()->detectPath($versionedFile);
-					}
-				}
-			}
-			closedir($dirContent);
-		}
-
-		// sort with newest version first
-		krsort($versions);
-
-		return $versions;
-	}
-
-	/**
-	 * Expire versions that older than max version retention time
-	 * @param string $uid
-	 */
-	public static function expireOlderThanMaxForUser($uid) {
-		$expiration = self::getExpiration();
-		$threshold = $expiration->getMaxAgeAsTimestamp();
-		$versions = self::getAllVersions($uid);
-		if (!$threshold || empty($versions['all'])) {
-			return;
-		}
-
-		$toDelete = [];
-		foreach (array_reverse($versions['all']) as $key => $version) {
-			if ((int)$version['version'] < $threshold) {
-				$toDelete[$key] = $version;
-			} else {
-				//Versions are sorted by time - nothing mo to iterate.
-				break;
-			}
-		}
-
-		$view = new View('/' . $uid . '/files_versions');
-		if (!empty($toDelete)) {
-			foreach ($toDelete as $version) {
-				\OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_RETENTION_CONSTRAINT]);
-				self::deleteVersion($view, $version['path'] . '.v' . $version['version']);
-				\OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_RETENTION_CONSTRAINT]);
-			}
-		}
-	}
-
-	/**
-	 * translate a timestamp into a string like "5 days ago"
-	 * @param int $timestamp
-	 * @return string for example "5 days ago"
-	 */
-	private static function getHumanReadableTimestamp($timestamp) {
-		$diff = time() - $timestamp;
-
-		if ($diff < 60) { // first minute
-			return  $diff . " seconds ago";
-		} elseif ($diff < 3600) { //first hour
-			return round($diff / 60) . " minutes ago";
-		} elseif ($diff < 86400) { // first day
-			return round($diff / 3600) . " hours ago";
-		} elseif ($diff < 604800) { //first week
-			return round($diff / 86400) . " days ago";
-		} elseif ($diff < 2419200) { //first month
-			return round($diff / 604800) . " weeks ago";
-		} elseif ($diff < 29030400) { // first year
-			return round($diff / 2419200) . " months ago";
-		} else {
-			return round($diff / 29030400) . " years ago";
-		}
-	}
-
-	/**
-	 * returns all stored file versions from a given user
-	 * @param string $uid id of the user
-	 * @return array with contains two arrays 'all' which contains all versions sorted by age and 'by_file' which contains all versions sorted by filename
-	 */
-	private static function getAllVersions($uid) {
-		$view = new View('/' . $uid . '/');
-		$dirs = [self::VERSIONS_ROOT];
-		$versions = [];
-
-		while (!empty($dirs)) {
-			$dir = array_pop($dirs);
-			$files = $view->getDirectoryContent($dir);
-
-			foreach ($files as $file) {
-				$fileData = $file->getData();
-				$filePath = $dir . '/' . $fileData['name'];
-				if ($file['type'] === 'dir') {
-					$dirs[] = $filePath;
-				} else {
-					$versionsBegin = strrpos($filePath, '.v');
-					$relPathStart = strlen(self::VERSIONS_ROOT);
-					$version = substr($filePath, $versionsBegin + 2);
-					$relpath = substr($filePath, $relPathStart, $versionsBegin - $relPathStart);
-					$key = $version . '#' . $relpath;
-					$versions[$key] = ['path' => $relpath, 'timestamp' => $version];
-				}
-			}
-		}
-
-		// newest version first
-		krsort($versions);
-
-		$result = [
-			'all' => [],
-			'by_file' => [],
-		];
-
-		foreach ($versions as $key => $value) {
-			$size = $view->filesize(self::VERSIONS_ROOT.'/'.$value['path'].'.v'.$value['timestamp']);
-			$filename = $value['path'];
-
-			$result['all'][$key]['version'] = $value['timestamp'];
-			$result['all'][$key]['path'] = $filename;
-			$result['all'][$key]['size'] = $size;
-
-			$result['by_file'][$filename][$key]['version'] = $value['timestamp'];
-			$result['by_file'][$filename][$key]['path'] = $filename;
-			$result['by_file'][$filename][$key]['size'] = $size;
-		}
-
-		return $result;
-	}
-
-	/**
-	 * get list of files we want to expire
-	 * @param array $versions list of versions
-	 * @param integer $time
-	 * @param bool $quotaExceeded is versions storage limit reached
-	 * @return array containing the list of to deleted versions and the size of them
-	 */
-	protected static function getExpireList($time, $versions, $quotaExceeded = false) {
-		$expiration = self::getExpiration();
-
-		if ($expiration->shouldAutoExpire()) {
-			list($toDelete, $size) = self::getAutoExpireList($time, $versions);
-		} else {
-			$size = 0;
-			$toDelete = [];  // versions we want to delete
-		}
-
-		foreach ($versions as $key => $version) {
-			if ($expiration->isExpired($version['version'], $quotaExceeded) && !isset($toDelete[$key])) {
-				$size += $version['size'];
-				$toDelete[$key] = $version['path'] . '.v' . $version['version'];
-			}
-		}
-
-		return [$toDelete, $size];
-	}
-
-	/**
-	 * get list of files we want to expire
-	 * @param array $versions list of versions
-	 * @param integer $time
-	 * @return array containing the list of to deleted versions and the size of them
-	 */
-	protected static function getAutoExpireList($time, $versions) {
-		$size = 0;
-		$toDelete = [];  // versions we want to delete
-
-		$interval = 1;
-		$step = Storage::$max_versions_per_interval[$interval]['step'];
-		if (Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'] === -1) {
-			$nextInterval = -1;
-		} else {
-			$nextInterval = $time - Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'];
-		}
-
-		$firstVersion = reset($versions);
-
-		if ($firstVersion === false) {
-			return [$toDelete, $size];
-		}
-
-		$firstKey = key($versions);
-		$prevTimestamp = $firstVersion['version'];
-		$nextVersion = $firstVersion['version'] - $step;
-		unset($versions[$firstKey]);
-
-		foreach ($versions as $key => $version) {
-			$newInterval = true;
-			while ($newInterval) {
-				if ($nextInterval === -1 || $prevTimestamp > $nextInterval) {
-					if ($version['version'] > $nextVersion) {
-						//distance between two version too small, mark to delete
-						$toDelete[$key] = $version['path'] . '.v' . $version['version'];
-						$size += $version['size'];
-						\OC::$server->getLogger()->info('Mark to expire '. $version['path'] .' next version should be ' . $nextVersion . " or smaller. (prevTimestamp: " . $prevTimestamp . "; step: " . $step, ['app' => 'files_versions']);
-					} else {
-						$nextVersion = $version['version'] - $step;
-						$prevTimestamp = $version['version'];
-					}
-					$newInterval = false; // version checked so we can move to the next one
-				} else { // time to move on to the next interval
-					$interval++;
-					$step = Storage::$max_versions_per_interval[$interval]['step'];
-					$nextVersion = $prevTimestamp - $step;
-					if (Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'] === -1) {
-						$nextInterval = -1;
-					} else {
-						$nextInterval = $time - Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'];
-					}
-					$newInterval = true; // we changed the interval -> check same version with new interval
-				}
-			}
-		}
-
-		return [$toDelete, $size];
-	}
-
-	/**
-	 * Schedule versions expiration for the given file
-	 *
-	 * @param string $uid owner of the file
-	 * @param string $fileName file/folder for which to schedule expiration
-	 */
-	public static function scheduleExpire($uid, $fileName) {
-		// let the admin disable auto expire
-		$expiration = self::getExpiration();
-		if ($expiration->isEnabled()) {
-			$command = new Expire($uid, $fileName);
-			\OC::$server->getCommandBus()->push($command);
-		}
-	}
-
-	/**
-	 * Expire versions which exceed the quota.
-	 *
-	 * This will setup the filesystem for the given user but will not
-	 * tear it down afterwards.
-	 *
-	 * @param string $filename path to file to expire
-	 * @param string $uid user for which to expire the version
-	 * @return bool|int|null
-	 */
-	public static function expire($filename, $uid) {
-		$expiration = self::getExpiration();
-
-		if ($expiration->isEnabled()) {
-			// get available disk space for user
-			$user = \OC::$server->getUserManager()->get($uid);
-			if (is_null($user)) {
-				\OC::$server->getLogger()->error('Backends provided no user object for ' . $uid, ['app' => 'files_versions']);
-				throw new \OC\User\NoUserException('Backends provided no user object for ' . $uid);
-			}
-
-			\OC_Util::setupFS($uid);
-
-			try {
-				if (!Filesystem::file_exists($filename)) {
-					return false;
-				}
-			} catch (StorageNotAvailableException $e) {
-				// if we can't check that the file hasn't been deleted we can only assume that it hasn't
-				// note that this `StorageNotAvailableException` is about the file the versions originate from,
-				// not the storage that the versions are stored on
-			}
-
-			if (empty($filename)) {
-				// file maybe renamed or deleted
-				return false;
-			}
-			$versionsFileview = new View('/'.$uid.'/files_versions');
-
-			$softQuota = true;
-			$quota = $user->getQuota();
-			if ($quota === null || $quota === 'none') {
-				$quota = Filesystem::free_space('/');
-				$softQuota = false;
-			} else {
-				$quota = \OCP\Util::computerFileSize($quota);
-			}
-
-			// make sure that we have the current size of the version history
-			$versionsSize = self::getVersionsSize($uid);
-
-			// calculate available space for version history
-			// subtract size of files and current versions size from quota
-			if ($quota >= 0) {
-				if ($softQuota) {
-					$userFolder = \OC::$server->getUserFolder($uid);
-					if (is_null($userFolder)) {
-						$availableSpace = 0;
-					} else {
-						$free = $quota - $userFolder->getSize(false); // remaining free space for user
-						if ($free > 0) {
-							$availableSpace = ($free * self::DEFAULTMAXSIZE / 100) - $versionsSize; // how much space can be used for versions
-						} else {
-							$availableSpace = $free - $versionsSize;
-						}
-					}
-				} else {
-					$availableSpace = $quota;
-				}
-			} else {
-				$availableSpace = PHP_INT_MAX;
-			}
-
-			$allVersions = Storage::getVersions($uid, $filename);
-
-			$time = time();
-			list($toDelete, $sizeOfDeletedVersions) = self::getExpireList($time, $allVersions, $availableSpace <= 0);
-
-			$availableSpace = $availableSpace + $sizeOfDeletedVersions;
-			$versionsSize = $versionsSize - $sizeOfDeletedVersions;
-
-			// if still not enough free space we rearrange the versions from all files
-			if ($availableSpace <= 0) {
-				$result = self::getAllVersions($uid);
-				$allVersions = $result['all'];
-
-				foreach ($result['by_file'] as $versions) {
-					list($toDeleteNew, $size) = self::getExpireList($time, $versions, $availableSpace <= 0);
-					$toDelete = array_merge($toDelete, $toDeleteNew);
-					$sizeOfDeletedVersions += $size;
-				}
-				$availableSpace = $availableSpace + $sizeOfDeletedVersions;
-				$versionsSize = $versionsSize - $sizeOfDeletedVersions;
-			}
-
-			$logger = \OC::$server->getLogger();
-			foreach ($toDelete as $key => $path) {
-				\OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $path, 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
-				self::deleteVersion($versionsFileview, $path);
-				\OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $path, 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
-				unset($allVersions[$key]); // update array with the versions we keep
-				$logger->info('Expire: ' . $path, ['app' => 'files_versions']);
-			}
-
-			// Check if enough space is available after versions are rearranged.
-			// If not we delete the oldest versions until we meet the size limit for versions,
-			// but always keep the two latest versions
-			$numOfVersions = count($allVersions) - 2 ;
-			$i = 0;
-			// sort oldest first and make sure that we start at the first element
-			ksort($allVersions);
-			reset($allVersions);
-			while ($availableSpace < 0 && $i < $numOfVersions) {
-				$version = current($allVersions);
-				\OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
-				self::deleteVersion($versionsFileview, $version['path'] . '.v' . $version['version']);
-				\OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
-				\OC::$server->getLogger()->info('running out of space! Delete oldest version: ' . $version['path'].'.v'.$version['version'], ['app' => 'files_versions']);
-				$versionsSize -= $version['size'];
-				$availableSpace += $version['size'];
-				next($allVersions);
-				$i++;
-			}
-
-			return $versionsSize; // finally return the new size of the version history
-		}
-
-		return false;
-	}
-
-	/**
-	 * Create recursively missing directories inside of files_versions
-	 * that match the given path to a file.
-	 *
-	 * @param string $filename $path to a file, relative to the user's
-	 * "files" folder
-	 * @param View $view view on data/user/
-	 */
-	public static function createMissingDirectories($filename, $view) {
-		$dirname = Filesystem::normalizePath(dirname($filename));
-		$dirParts = explode('/', $dirname);
-		$dir = "/files_versions";
-		foreach ($dirParts as $part) {
-			$dir = $dir . '/' . $part;
-			if (!$view->file_exists($dir)) {
-				$view->mkdir($dir);
-			}
-		}
-	}
-
-	/**
-	 * Static workaround
-	 * @return Expiration
-	 */
-	protected static function getExpiration() {
-		if (self::$application === null) {
-			self::$application = \OC::$server->query(Application::class);
-		}
-		return self::$application->getContainer()->query(Expiration::class);
-	}
+    public const DEFAULTENABLED = true;
+    public const DEFAULTMAXSIZE = 50; // unit: percentage; 50% of available disk space/quota
+    public const VERSIONS_ROOT = 'files_versions/';
+
+    public const DELETE_TRIGGER_MASTER_REMOVED = 0;
+    public const DELETE_TRIGGER_RETENTION_CONSTRAINT = 1;
+    public const DELETE_TRIGGER_QUOTA_EXCEEDED = 2;
+
+    // files for which we can remove the versions after the delete operation was successful
+    private static $deletedFiles = [];
+
+    private static $sourcePathAndUser = [];
+
+    private static $max_versions_per_interval = [
+        //first 10sec, one version every 2sec
+        1 => ['intervalEndsAfter' => 10,      'step' => 2],
+        //next minute, one version every 10sec
+        2 => ['intervalEndsAfter' => 60,      'step' => 10],
+        //next hour, one version every minute
+        3 => ['intervalEndsAfter' => 3600,    'step' => 60],
+        //next 24h, one version every hour
+        4 => ['intervalEndsAfter' => 86400,   'step' => 3600],
+        //next 30days, one version per day
+        5 => ['intervalEndsAfter' => 2592000, 'step' => 86400],
+        //until the end one version per week
+        6 => ['intervalEndsAfter' => -1,      'step' => 604800],
+    ];
+
+    /** @var \OCA\Files_Versions\AppInfo\Application */
+    private static $application;
+
+    /**
+     * get the UID of the owner of the file and the path to the file relative to
+     * owners files folder
+     *
+     * @param string $filename
+     * @return array
+     * @throws \OC\User\NoUserException
+     */
+    public static function getUidAndFilename($filename) {
+        $uid = Filesystem::getOwner($filename);
+        $userManager = \OC::$server->getUserManager();
+        // if the user with the UID doesn't exists, e.g. because the UID points
+        // to a remote user with a federated cloud ID we use the current logged-in
+        // user. We need a valid local user to create the versions
+        if (!$userManager->userExists($uid)) {
+            $uid = User::getUser();
+        }
+        Filesystem::initMountPoints($uid);
+        if ($uid !== User::getUser()) {
+            $info = Filesystem::getFileInfo($filename);
+            $ownerView = new View('/'.$uid.'/files');
+            try {
+                $filename = $ownerView->getPath($info['fileid']);
+                // make sure that the file name doesn't end with a trailing slash
+                // can for example happen single files shared across servers
+                $filename = rtrim($filename, '/');
+            } catch (NotFoundException $e) {
+                $filename = null;
+            }
+        }
+        return [$uid, $filename];
+    }
+
+    /**
+     * Remember the owner and the owner path of the source file
+     *
+     * @param string $source source path
+     */
+    public static function setSourcePathAndUser($source) {
+        list($uid, $path) = self::getUidAndFilename($source);
+        self::$sourcePathAndUser[$source] = ['uid' => $uid, 'path' => $path];
+    }
+
+    /**
+     * Gets the owner and the owner path from the source path
+     *
+     * @param string $source source path
+     * @return array with user id and path
+     */
+    public static function getSourcePathAndUser($source) {
+        if (isset(self::$sourcePathAndUser[$source])) {
+            $uid = self::$sourcePathAndUser[$source]['uid'];
+            $path = self::$sourcePathAndUser[$source]['path'];
+            unset(self::$sourcePathAndUser[$source]);
+        } else {
+            $uid = $path = false;
+        }
+        return [$uid, $path];
+    }
+
+    /**
+     * get current size of all versions from a given user
+     *
+     * @param string $user user who owns the versions
+     * @return int versions size
+     */
+    private static function getVersionsSize($user) {
+        $view = new View('/' . $user);
+        $fileInfo = $view->getFileInfo('/files_versions');
+        return isset($fileInfo['size']) ? $fileInfo['size'] : 0;
+    }
+
+    /**
+     * store a new version of a file.
+     */
+    public static function store($filename) {
+
+        // if the file gets streamed we need to remove the .part extension
+        // to get the right target
+        $ext = pathinfo($filename, PATHINFO_EXTENSION);
+        if ($ext === 'part') {
+            $filename = substr($filename, 0, -5);
+        }
+
+        // we only handle existing files
+        if (! Filesystem::file_exists($filename) || Filesystem::is_dir($filename)) {
+            return false;
+        }
+
+        list($uid, $filename) = self::getUidAndFilename($filename);
+
+        $files_view = new View('/'.$uid .'/files');
+
+        $eventDispatcher = \OC::$server->getEventDispatcher();
+        $fileInfo = $files_view->getFileInfo($filename);
+        $id = $fileInfo->getId();
+        $nodes = \OC::$server->getRootFolder()->getUserFolder($uid)->getById($id);
+        foreach ($nodes as $node) {
+            $event = new CreateVersionEvent($node);
+            $eventDispatcher->dispatch('OCA\Files_Versions::createVersion', $event);
+            if ($event->shouldCreateVersion() === false) {
+                return false;
+            }
+        }
+
+        // no use making versions for empty files
+        if ($fileInfo->getSize() === 0) {
+            return false;
+        }
+
+        /** @var IVersionManager $versionManager */
+        $versionManager = \OC::$server->query(IVersionManager::class);
+        $userManager = \OC::$server->getUserManager();
+        $user = $userManager->get($uid);
+
+        $versionManager->createVersion($user, $fileInfo);
+    }
+
+
+    /**
+     * mark file as deleted so that we can remove the versions if the file is gone
+     * @param string $path
+     */
+    public static function markDeletedFile($path) {
+        list($uid, $filename) = self::getUidAndFilename($path);
+        self::$deletedFiles[$path] = [
+            'uid' => $uid,
+            'filename' => $filename];
+    }
+
+    /**
+     * delete the version from the storage and cache
+     *
+     * @param View $view
+     * @param string $path
+     */
+    protected static function deleteVersion($view, $path) {
+        $view->unlink($path);
+        /**
+         * @var \OC\Files\Storage\Storage $storage
+         * @var string $internalPath
+         */
+        list($storage, $internalPath) = $view->resolvePath($path);
+        $cache = $storage->getCache($internalPath);
+        $cache->remove($internalPath);
+    }
+
+    /**
+     * Delete versions of a file
+     */
+    public static function delete($path) {
+        $deletedFile = self::$deletedFiles[$path];
+        $uid = $deletedFile['uid'];
+        $filename = $deletedFile['filename'];
+
+        if (!Filesystem::file_exists($path)) {
+            $view = new View('/' . $uid . '/files_versions');
+
+            $versions = self::getVersions($uid, $filename);
+            if (!empty($versions)) {
+                foreach ($versions as $v) {
+                    \OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $path . $v['version'], 'trigger' => self::DELETE_TRIGGER_MASTER_REMOVED]);
+                    self::deleteVersion($view, $filename . '.v' . $v['version']);
+                    \OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $path . $v['version'], 'trigger' => self::DELETE_TRIGGER_MASTER_REMOVED]);
+                }
+            }
+        }
+        unset(self::$deletedFiles[$path]);
+    }
+
+    /**
+     * Rename or copy versions of a file of the given paths
+     *
+     * @param string $sourcePath source path of the file to move, relative to
+     * the currently logged in user's "files" folder
+     * @param string $targetPath target path of the file to move, relative to
+     * the currently logged in user's "files" folder
+     * @param string $operation can be 'copy' or 'rename'
+     */
+    public static function renameOrCopy($sourcePath, $targetPath, $operation) {
+        list($sourceOwner, $sourcePath) = self::getSourcePathAndUser($sourcePath);
+
+        // it was a upload of a existing file if no old path exists
+        // in this case the pre-hook already called the store method and we can
+        // stop here
+        if ($sourcePath === false) {
+            return true;
+        }
+
+        list($targetOwner, $targetPath) = self::getUidAndFilename($targetPath);
+
+        $sourcePath = ltrim($sourcePath, '/');
+        $targetPath = ltrim($targetPath, '/');
+
+        $rootView = new View('');
+
+        // did we move a directory ?
+        if ($rootView->is_dir('/' . $targetOwner . '/files/' . $targetPath)) {
+            // does the directory exists for versions too ?
+            if ($rootView->is_dir('/' . $sourceOwner . '/files_versions/' . $sourcePath)) {
+                // create missing dirs if necessary
+                self::createMissingDirectories($targetPath, new View('/'. $targetOwner));
+
+                // move the directory containing the versions
+                $rootView->$operation(
+                    '/' . $sourceOwner . '/files_versions/' . $sourcePath,
+                    '/' . $targetOwner . '/files_versions/' . $targetPath
+                );
+            }
+        } elseif ($versions = Storage::getVersions($sourceOwner, '/' . $sourcePath)) {
+            // create missing dirs if necessary
+            self::createMissingDirectories($targetPath, new View('/'. $targetOwner));
+
+            foreach ($versions as $v) {
+                // move each version one by one to the target directory
+                $rootView->$operation(
+                    '/' . $sourceOwner . '/files_versions/' . $sourcePath.'.v' . $v['version'],
+                    '/' . $targetOwner . '/files_versions/' . $targetPath.'.v'.$v['version']
+                );
+            }
+        }
+
+        // if we moved versions directly for a file, schedule expiration check for that file
+        if (!$rootView->is_dir('/' . $targetOwner . '/files/' . $targetPath)) {
+            self::scheduleExpire($targetOwner, $targetPath);
+        }
+    }
+
+    /**
+     * Rollback to an old version of a file.
+     *
+     * @param string $file file name
+     * @param int $revision revision timestamp
+     * @return bool
+     */
+    public static function rollback(string $file, int $revision, IUser $user) {
+
+        // add expected leading slash
+        $filename = '/' . ltrim($file, '/');
+
+        // Fetch the userfolder to trigger view hooks
+        $userFolder = \OC::$server->getUserFolder($user->getUID());
+
+        $users_view = new View('/'.$user->getUID());
+        $files_view = new View('/'. $user->getUID().'/files');
+
+        $versionCreated = false;
+
+        $fileInfo = $files_view->getFileInfo($file);
+
+        // check if user has the permissions to revert a version
+        if (!$fileInfo->isUpdateable()) {
+            return false;
+        }
+
+        //first create a new version
+        $version = 'files_versions'.$filename.'.v'.$users_view->filemtime('files'.$filename);
+        if (!$users_view->file_exists($version)) {
+            $users_view->copy('files'.$filename, 'files_versions'.$filename.'.v'.$users_view->filemtime('files'.$filename));
+            $versionCreated = true;
+        }
+
+        $fileToRestore = 'files_versions' . $filename . '.v' . $revision;
+
+        // Restore encrypted version of the old file for the newly restored file
+        // This has to happen manually here since the file is manually copied below
+        $oldVersion = $users_view->getFileInfo($fileToRestore)->getEncryptedVersion();
+        $oldFileInfo = $users_view->getFileInfo($fileToRestore);
+        $cache = $fileInfo->getStorage()->getCache();
+        $cache->update(
+            $fileInfo->getId(), [
+                'encrypted' => $oldVersion,
+                'encryptedVersion' => $oldVersion,
+                'size' => $oldFileInfo->getSize()
+            ]
+        );
+
+        // rollback
+        if (self::copyFileContents($users_view, $fileToRestore, 'files' . $filename)) {
+            $files_view->touch($file, $revision);
+            Storage::scheduleExpire($user->getUID(), $file);
+
+            $node = $userFolder->get($file);
+
+            // TODO: move away from those legacy hooks!
+            \OC_Hook::emit('\OCP\Versions', 'rollback', [
+                'path' => $filename,
+                'revision' => $revision,
+                'node' => $node,
+            ]);
+            return true;
+        } elseif ($versionCreated) {
+            self::deleteVersion($users_view, $version);
+        }
+
+        return false;
+    }
+
+    /**
+     * Stream copy file contents from $path1 to $path2
+     *
+     * @param View $view view to use for copying
+     * @param string $path1 source file to copy
+     * @param string $path2 target file
+     *
+     * @return bool true for success, false otherwise
+     */
+    private static function copyFileContents($view, $path1, $path2) {
+        /** @var \OC\Files\Storage\Storage $storage1 */
+        list($storage1, $internalPath1) = $view->resolvePath($path1);
+        /** @var \OC\Files\Storage\Storage $storage2 */
+        list($storage2, $internalPath2) = $view->resolvePath($path2);
+
+        $view->lockFile($path1, ILockingProvider::LOCK_EXCLUSIVE);
+        $view->lockFile($path2, ILockingProvider::LOCK_EXCLUSIVE);
+
+        // TODO add a proper way of overwriting a file while maintaining file ids
+        if ($storage1->instanceOfStorage('\OC\Files\ObjectStore\ObjectStoreStorage') || $storage2->instanceOfStorage('\OC\Files\ObjectStore\ObjectStoreStorage')) {
+            $source = $storage1->fopen($internalPath1, 'r');
+            $target = $storage2->fopen($internalPath2, 'w');
+            list(, $result) = \OC_Helper::streamCopy($source, $target);
+            fclose($source);
+            fclose($target);
+
+            if ($result !== false) {
+                $storage1->unlink($internalPath1);
+            }
+        } else {
+            $result = $storage2->moveFromStorage($storage1, $internalPath1, $internalPath2);
+        }
+
+        $view->unlockFile($path1, ILockingProvider::LOCK_EXCLUSIVE);
+        $view->unlockFile($path2, ILockingProvider::LOCK_EXCLUSIVE);
+
+        return ($result !== false);
+    }
+
+    /**
+     * get a list of all available versions of a file in descending chronological order
+     * @param string $uid user id from the owner of the file
+     * @param string $filename file to find versions of, relative to the user files dir
+     * @param string $userFullPath
+     * @return array versions newest version first
+     */
+    public static function getVersions($uid, $filename, $userFullPath = '') {
+        $versions = [];
+        if (empty($filename)) {
+            return $versions;
+        }
+        // fetch for old versions
+        $view = new View('/' . $uid . '/');
+
+        $pathinfo = pathinfo($filename);
+        $versionedFile = $pathinfo['basename'];
+
+        $dir = Filesystem::normalizePath(self::VERSIONS_ROOT . '/' . $pathinfo['dirname']);
+
+        $dirContent = false;
+        if ($view->is_dir($dir)) {
+            $dirContent = $view->opendir($dir);
+        }
+
+        if ($dirContent === false) {
+            return $versions;
+        }
+
+        if (is_resource($dirContent)) {
+            while (($entryName = readdir($dirContent)) !== false) {
+                if (!Filesystem::isIgnoredDir($entryName)) {
+                    $pathparts = pathinfo($entryName);
+                    $filename = $pathparts['filename'];
+                    if ($filename === $versionedFile) {
+                        $pathparts = pathinfo($entryName);
+                        $timestamp = substr($pathparts['extension'], 1);
+                        $filename = $pathparts['filename'];
+                        $key = $timestamp . '#' . $filename;
+                        $versions[$key]['version'] = $timestamp;
+                        $versions[$key]['humanReadableTimestamp'] = self::getHumanReadableTimestamp($timestamp);
+                        if (empty($userFullPath)) {
+                            $versions[$key]['preview'] = '';
+                        } else {
+                            $versions[$key]['preview'] = \OC::$server->getURLGenerator('files_version.Preview.getPreview', ['file' => $userFullPath, 'version' => $timestamp]);
+                        }
+                        $versions[$key]['path'] = Filesystem::normalizePath($pathinfo['dirname'] . '/' . $filename);
+                        $versions[$key]['name'] = $versionedFile;
+                        $versions[$key]['size'] = $view->filesize($dir . '/' . $entryName);
+                        $versions[$key]['mimetype'] = \OC::$server->getMimeTypeDetector()->detectPath($versionedFile);
+                    }
+                }
+            }
+            closedir($dirContent);
+        }
+
+        // sort with newest version first
+        krsort($versions);
+
+        return $versions;
+    }
+
+    /**
+     * Expire versions that older than max version retention time
+     * @param string $uid
+     */
+    public static function expireOlderThanMaxForUser($uid) {
+        $expiration = self::getExpiration();
+        $threshold = $expiration->getMaxAgeAsTimestamp();
+        $versions = self::getAllVersions($uid);
+        if (!$threshold || empty($versions['all'])) {
+            return;
+        }
+
+        $toDelete = [];
+        foreach (array_reverse($versions['all']) as $key => $version) {
+            if ((int)$version['version'] < $threshold) {
+                $toDelete[$key] = $version;
+            } else {
+                //Versions are sorted by time - nothing mo to iterate.
+                break;
+            }
+        }
+
+        $view = new View('/' . $uid . '/files_versions');
+        if (!empty($toDelete)) {
+            foreach ($toDelete as $version) {
+                \OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_RETENTION_CONSTRAINT]);
+                self::deleteVersion($view, $version['path'] . '.v' . $version['version']);
+                \OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_RETENTION_CONSTRAINT]);
+            }
+        }
+    }
+
+    /**
+     * translate a timestamp into a string like "5 days ago"
+     * @param int $timestamp
+     * @return string for example "5 days ago"
+     */
+    private static function getHumanReadableTimestamp($timestamp) {
+        $diff = time() - $timestamp;
+
+        if ($diff < 60) { // first minute
+            return  $diff . " seconds ago";
+        } elseif ($diff < 3600) { //first hour
+            return round($diff / 60) . " minutes ago";
+        } elseif ($diff < 86400) { // first day
+            return round($diff / 3600) . " hours ago";
+        } elseif ($diff < 604800) { //first week
+            return round($diff / 86400) . " days ago";
+        } elseif ($diff < 2419200) { //first month
+            return round($diff / 604800) . " weeks ago";
+        } elseif ($diff < 29030400) { // first year
+            return round($diff / 2419200) . " months ago";
+        } else {
+            return round($diff / 29030400) . " years ago";
+        }
+    }
+
+    /**
+     * returns all stored file versions from a given user
+     * @param string $uid id of the user
+     * @return array with contains two arrays 'all' which contains all versions sorted by age and 'by_file' which contains all versions sorted by filename
+     */
+    private static function getAllVersions($uid) {
+        $view = new View('/' . $uid . '/');
+        $dirs = [self::VERSIONS_ROOT];
+        $versions = [];
+
+        while (!empty($dirs)) {
+            $dir = array_pop($dirs);
+            $files = $view->getDirectoryContent($dir);
+
+            foreach ($files as $file) {
+                $fileData = $file->getData();
+                $filePath = $dir . '/' . $fileData['name'];
+                if ($file['type'] === 'dir') {
+                    $dirs[] = $filePath;
+                } else {
+                    $versionsBegin = strrpos($filePath, '.v');
+                    $relPathStart = strlen(self::VERSIONS_ROOT);
+                    $version = substr($filePath, $versionsBegin + 2);
+                    $relpath = substr($filePath, $relPathStart, $versionsBegin - $relPathStart);
+                    $key = $version . '#' . $relpath;
+                    $versions[$key] = ['path' => $relpath, 'timestamp' => $version];
+                }
+            }
+        }
+
+        // newest version first
+        krsort($versions);
+
+        $result = [
+            'all' => [],
+            'by_file' => [],
+        ];
+
+        foreach ($versions as $key => $value) {
+            $size = $view->filesize(self::VERSIONS_ROOT.'/'.$value['path'].'.v'.$value['timestamp']);
+            $filename = $value['path'];
+
+            $result['all'][$key]['version'] = $value['timestamp'];
+            $result['all'][$key]['path'] = $filename;
+            $result['all'][$key]['size'] = $size;
+
+            $result['by_file'][$filename][$key]['version'] = $value['timestamp'];
+            $result['by_file'][$filename][$key]['path'] = $filename;
+            $result['by_file'][$filename][$key]['size'] = $size;
+        }
+
+        return $result;
+    }
+
+    /**
+     * get list of files we want to expire
+     * @param array $versions list of versions
+     * @param integer $time
+     * @param bool $quotaExceeded is versions storage limit reached
+     * @return array containing the list of to deleted versions and the size of them
+     */
+    protected static function getExpireList($time, $versions, $quotaExceeded = false) {
+        $expiration = self::getExpiration();
+
+        if ($expiration->shouldAutoExpire()) {
+            list($toDelete, $size) = self::getAutoExpireList($time, $versions);
+        } else {
+            $size = 0;
+            $toDelete = [];  // versions we want to delete
+        }
+
+        foreach ($versions as $key => $version) {
+            if ($expiration->isExpired($version['version'], $quotaExceeded) && !isset($toDelete[$key])) {
+                $size += $version['size'];
+                $toDelete[$key] = $version['path'] . '.v' . $version['version'];
+            }
+        }
+
+        return [$toDelete, $size];
+    }
+
+    /**
+     * get list of files we want to expire
+     * @param array $versions list of versions
+     * @param integer $time
+     * @return array containing the list of to deleted versions and the size of them
+     */
+    protected static function getAutoExpireList($time, $versions) {
+        $size = 0;
+        $toDelete = [];  // versions we want to delete
+
+        $interval = 1;
+        $step = Storage::$max_versions_per_interval[$interval]['step'];
+        if (Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'] === -1) {
+            $nextInterval = -1;
+        } else {
+            $nextInterval = $time - Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'];
+        }
+
+        $firstVersion = reset($versions);
+
+        if ($firstVersion === false) {
+            return [$toDelete, $size];
+        }
+
+        $firstKey = key($versions);
+        $prevTimestamp = $firstVersion['version'];
+        $nextVersion = $firstVersion['version'] - $step;
+        unset($versions[$firstKey]);
+
+        foreach ($versions as $key => $version) {
+            $newInterval = true;
+            while ($newInterval) {
+                if ($nextInterval === -1 || $prevTimestamp > $nextInterval) {
+                    if ($version['version'] > $nextVersion) {
+                        //distance between two version too small, mark to delete
+                        $toDelete[$key] = $version['path'] . '.v' . $version['version'];
+                        $size += $version['size'];
+                        \OC::$server->getLogger()->info('Mark to expire '. $version['path'] .' next version should be ' . $nextVersion . " or smaller. (prevTimestamp: " . $prevTimestamp . "; step: " . $step, ['app' => 'files_versions']);
+                    } else {
+                        $nextVersion = $version['version'] - $step;
+                        $prevTimestamp = $version['version'];
+                    }
+                    $newInterval = false; // version checked so we can move to the next one
+                } else { // time to move on to the next interval
+                    $interval++;
+                    $step = Storage::$max_versions_per_interval[$interval]['step'];
+                    $nextVersion = $prevTimestamp - $step;
+                    if (Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'] === -1) {
+                        $nextInterval = -1;
+                    } else {
+                        $nextInterval = $time - Storage::$max_versions_per_interval[$interval]['intervalEndsAfter'];
+                    }
+                    $newInterval = true; // we changed the interval -> check same version with new interval
+                }
+            }
+        }
+
+        return [$toDelete, $size];
+    }
+
+    /**
+     * Schedule versions expiration for the given file
+     *
+     * @param string $uid owner of the file
+     * @param string $fileName file/folder for which to schedule expiration
+     */
+    public static function scheduleExpire($uid, $fileName) {
+        // let the admin disable auto expire
+        $expiration = self::getExpiration();
+        if ($expiration->isEnabled()) {
+            $command = new Expire($uid, $fileName);
+            \OC::$server->getCommandBus()->push($command);
+        }
+    }
+
+    /**
+     * Expire versions which exceed the quota.
+     *
+     * This will setup the filesystem for the given user but will not
+     * tear it down afterwards.
+     *
+     * @param string $filename path to file to expire
+     * @param string $uid user for which to expire the version
+     * @return bool|int|null
+     */
+    public static function expire($filename, $uid) {
+        $expiration = self::getExpiration();
+
+        if ($expiration->isEnabled()) {
+            // get available disk space for user
+            $user = \OC::$server->getUserManager()->get($uid);
+            if (is_null($user)) {
+                \OC::$server->getLogger()->error('Backends provided no user object for ' . $uid, ['app' => 'files_versions']);
+                throw new \OC\User\NoUserException('Backends provided no user object for ' . $uid);
+            }
+
+            \OC_Util::setupFS($uid);
+
+            try {
+                if (!Filesystem::file_exists($filename)) {
+                    return false;
+                }
+            } catch (StorageNotAvailableException $e) {
+                // if we can't check that the file hasn't been deleted we can only assume that it hasn't
+                // note that this `StorageNotAvailableException` is about the file the versions originate from,
+                // not the storage that the versions are stored on
+            }
+
+            if (empty($filename)) {
+                // file maybe renamed or deleted
+                return false;
+            }
+            $versionsFileview = new View('/'.$uid.'/files_versions');
+
+            $softQuota = true;
+            $quota = $user->getQuota();
+            if ($quota === null || $quota === 'none') {
+                $quota = Filesystem::free_space('/');
+                $softQuota = false;
+            } else {
+                $quota = \OCP\Util::computerFileSize($quota);
+            }
+
+            // make sure that we have the current size of the version history
+            $versionsSize = self::getVersionsSize($uid);
+
+            // calculate available space for version history
+            // subtract size of files and current versions size from quota
+            if ($quota >= 0) {
+                if ($softQuota) {
+                    $userFolder = \OC::$server->getUserFolder($uid);
+                    if (is_null($userFolder)) {
+                        $availableSpace = 0;
+                    } else {
+                        $free = $quota - $userFolder->getSize(false); // remaining free space for user
+                        if ($free > 0) {
+                            $availableSpace = ($free * self::DEFAULTMAXSIZE / 100) - $versionsSize; // how much space can be used for versions
+                        } else {
+                            $availableSpace = $free - $versionsSize;
+                        }
+                    }
+                } else {
+                    $availableSpace = $quota;
+                }
+            } else {
+                $availableSpace = PHP_INT_MAX;
+            }
+
+            $allVersions = Storage::getVersions($uid, $filename);
+
+            $time = time();
+            list($toDelete, $sizeOfDeletedVersions) = self::getExpireList($time, $allVersions, $availableSpace <= 0);
+
+            $availableSpace = $availableSpace + $sizeOfDeletedVersions;
+            $versionsSize = $versionsSize - $sizeOfDeletedVersions;
+
+            // if still not enough free space we rearrange the versions from all files
+            if ($availableSpace <= 0) {
+                $result = self::getAllVersions($uid);
+                $allVersions = $result['all'];
+
+                foreach ($result['by_file'] as $versions) {
+                    list($toDeleteNew, $size) = self::getExpireList($time, $versions, $availableSpace <= 0);
+                    $toDelete = array_merge($toDelete, $toDeleteNew);
+                    $sizeOfDeletedVersions += $size;
+                }
+                $availableSpace = $availableSpace + $sizeOfDeletedVersions;
+                $versionsSize = $versionsSize - $sizeOfDeletedVersions;
+            }
+
+            $logger = \OC::$server->getLogger();
+            foreach ($toDelete as $key => $path) {
+                \OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $path, 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
+                self::deleteVersion($versionsFileview, $path);
+                \OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $path, 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
+                unset($allVersions[$key]); // update array with the versions we keep
+                $logger->info('Expire: ' . $path, ['app' => 'files_versions']);
+            }
+
+            // Check if enough space is available after versions are rearranged.
+            // If not we delete the oldest versions until we meet the size limit for versions,
+            // but always keep the two latest versions
+            $numOfVersions = count($allVersions) - 2 ;
+            $i = 0;
+            // sort oldest first and make sure that we start at the first element
+            ksort($allVersions);
+            reset($allVersions);
+            while ($availableSpace < 0 && $i < $numOfVersions) {
+                $version = current($allVersions);
+                \OC_Hook::emit('\OCP\Versions', 'preDelete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
+                self::deleteVersion($versionsFileview, $version['path'] . '.v' . $version['version']);
+                \OC_Hook::emit('\OCP\Versions', 'delete', ['path' => $version['path'].'.v'.$version['version'], 'trigger' => self::DELETE_TRIGGER_QUOTA_EXCEEDED]);
+                \OC::$server->getLogger()->info('running out of space! Delete oldest version: ' . $version['path'].'.v'.$version['version'], ['app' => 'files_versions']);
+                $versionsSize -= $version['size'];
+                $availableSpace += $version['size'];
+                next($allVersions);
+                $i++;
+            }
+
+            return $versionsSize; // finally return the new size of the version history
+        }
+
+        return false;
+    }
+
+    /**
+     * Create recursively missing directories inside of files_versions
+     * that match the given path to a file.
+     *
+     * @param string $filename $path to a file, relative to the user's
+     * "files" folder
+     * @param View $view view on data/user/
+     */
+    public static function createMissingDirectories($filename, $view) {
+        $dirname = Filesystem::normalizePath(dirname($filename));
+        $dirParts = explode('/', $dirname);
+        $dir = "/files_versions";
+        foreach ($dirParts as $part) {
+            $dir = $dir . '/' . $part;
+            if (!$view->file_exists($dir)) {
+                $view->mkdir($dir);
+            }
+        }
+    }
+
+    /**
+     * Static workaround
+     * @return Expiration
+     */
+    protected static function getExpiration() {
+        if (self::$application === null) {
+            self::$application = \OC::$server->query(Application::class);
+        }
+        return self::$application->getContainer()->query(Expiration::class);
+    }
 }