Revert "Do not cache file ids in FileSystemTags"

This reverts commit d5e3306.

Author: st3iny

apps/workflowengine/lib/Check/FileSystemTags.php

@@ -6,7 +6,6 @@
  * @author Christoph Wurst <christoph@winzerhof-wurst.at>
  * @author Joas Schilling <coding@schilljs.com>
  * @author Julius Härtl <jus@bitgrid.net>
- * @author Richard Steinmetz <richard@steinmetz.cloud>
  *
  * @license GNU AGPL version 3 or any later version
  *
@@ -40,6 +39,9 @@
 class FileSystemTags implements ICheck, IFileCheck {
 	use TFileCheck;
 
+	/** @var array */
+	protected $fileIds;
+
 	/** @var array */
 	protected $fileSystemTags;
 
@@ -129,6 +131,11 @@ protected function getSystemTags() {
 	 * @return int[]
 	 */
 	protected function getFileIds(ICache $cache, $path, $isExternalStorage) {
+		$cacheId = $cache->getNumericStorageId();
+		if (isset($this->fileIds[$cacheId][$path])) {
+			return $this->fileIds[$cacheId][$path];
+		}
+
 		$parentIds = [];
 		if ($path !== $this->dirname($path)) {
 			$parentIds = $this->getFileIds($cache, $this->dirname($path), $isExternalStorage);
@@ -141,6 +148,8 @@ protected function getFileIds(ICache $cache, $path, $isExternalStorage) {
 			$parentIds[] = $cache->getId($path);
 		}
 
+		$this->fileIds[$cacheId][$path] = $parentIds;
+
 		return $parentIds;
 	}