feat: add an option to filter what paths get checked for updates

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/Files/Cache/Watcher.php

@@ -36,6 +36,8 @@ class Watcher implements IWatcher {
 	/** @var callable[] */
 	protected $onUpdate = [];
 
+	protected ?string $checkFilter = null;
+
 	/**
 	 * @param \OC\Files\Storage\Storage $storage
 	 */
@@ -52,6 +54,10 @@ class Watcher implements IWatcher {
 		$this->watchPolicy = $policy;
 	}
 
+	public function setCheckFilter(?string $filter): void {
+		$this->checkFilter = $filter;
+	}
+
 	/**
 	 * @return int either \OC\Files\Cache\Watcher::CHECK_NEVER, \OC\Files\Cache\Watcher::CHECK_ONCE, \OC\Files\Cache\Watcher::CHECK_ALWAYS
 	 */
@@ -116,6 +122,12 @@ class Watcher implements IWatcher {
 	 * @return bool
 	 */
 	public function needsUpdate($path, $cachedData) {
+		if ($this->checkFilter !== null) {
+			if (!preg_match($this->checkFilter, $path)) {
+				return false;
+			}
+		}
+
 		if ($this->watchPolicy === self::CHECK_ALWAYS || ($this->watchPolicy === self::CHECK_ONCE && !in_array($path, $this->checkedPaths))) {
 			$this->checkedPaths[] = $path;
 			return $cachedData['storage_mtime'] === null || $this->storage->hasUpdated($path, $cachedData['storage_mtime']);

lib/private/Files/Storage/Common.php

@@ -331,6 +331,7 @@ abstract class Common implements Storage, ILockingStorage, IWriteStreamStorage,
 			$this->watcher = new Watcher($storage);
 			$globalPolicy = Server::get(IConfig::class)->getSystemValueInt('filesystem_check_changes', Watcher::CHECK_NEVER);
 			$this->watcher->setPolicy((int)$this->getMountOption('filesystem_check_changes', $globalPolicy));
+			$this->watcher->setCheckFilter($this->getMountOption('filesystem_check_filter'));
 		}
 		return $this->watcher;
 	}

lib/public/Files/Cache/IWatcher.php

@@ -34,6 +34,17 @@ interface IWatcher {
 	 */
 	public function setPolicy($policy);
 
+	/**
+	 * Set a filter regex, only paths matching the regex will be checked for updates.
+	 *
+	 * When set to `null`, every path will be checked for updates
+	 *
+	 * @param ?string $filter
+	 * @return void
+	 * @since 33.0.0
+	 */
+	public function setCheckFilter(?string $filter): void;
+
 	/**
 	 * @return int either IWatcher::CHECK_NEVER, IWatcher::CHECK_ONCE, IWatcher::CHECK_ALWAYS
 	 * @since 9.0.0