diff --git a/apps/files_sharing/lib/watcher.php b/apps/files_sharing/lib/watcher.php
index 9a8968f226..5b4736c21e 100644
--- a/apps/files_sharing/lib/watcher.php
+++ b/apps/files_sharing/lib/watcher.php
@@ -24,6 +24,7 @@
  */
 
 namespace OC\Files\Cache;
+use OCP\Files\Cache\ICacheEntry;
 
 /**
  * check the storage backends for updates and change the cache accordingly
@@ -38,7 +39,7 @@ class Shared_Watcher extends Watcher {
 	 * Update the cache for changes to $path
 	 *
 	 * @param string $path
-	 * @param array $cachedData
+	 * @param ICacheEntry $cachedData
 	 */
 	public function update($path, $cachedData) {
 		parent::update($path, $cachedData);
diff --git a/lib/private/files/cache/watcher.php b/lib/private/files/cache/watcher.php
index bb80dcbd80..a00e875a2d 100644
--- a/lib/private/files/cache/watcher.php
+++ b/lib/private/files/cache/watcher.php
@@ -22,14 +22,13 @@
  */
 
 namespace OC\Files\Cache;
+use OCP\Files\Cache\ICacheEntry;
+use OCP\Files\Cache\IWatcher;
 
 /**
  * check the storage backends for updates and change the cache accordingly
  */
-class Watcher {
-	const CHECK_NEVER = 0; // never check the underlying filesystem for updates
-	const CHECK_ONCE = 1; // check the underlying filesystem for updates once every request for each file
-	const CHECK_ALWAYS = 2; // always check the underlying filesystem for updates
+class Watcher implements IWatcher {
 
 	protected $watchPolicy = self::CHECK_ONCE;
 
@@ -77,7 +76,7 @@ class Watcher {
 	 * check $path for updates and update if needed
 	 *
 	 * @param string $path
-	 * @param array $cachedEntry
+	 * @param ICacheEntry|null $cachedEntry
 	 * @return boolean true if path was updated
 	 */
 	public function checkUpdate($path, $cachedEntry = null) {
@@ -96,7 +95,7 @@ class Watcher {
 	 * Update the cache for changes to $path
 	 *
 	 * @param string $path
-	 * @param array $cachedData
+	 * @param ICacheEntry $cachedData
 	 */
 	public function update($path, $cachedData) {
 		if ($this->storage->is_dir($path)) {
@@ -114,7 +113,7 @@ class Watcher {
 	 * Check if the cache for $path needs to be updated
 	 *
 	 * @param string $path
-	 * @param array $cachedData
+	 * @param ICacheEntry $cachedData
 	 * @return bool
 	 */
 	public function needsUpdate($path, $cachedData) {
diff --git a/lib/public/files/cache/iwatcher.php b/lib/public/files/cache/iwatcher.php
new file mode 100644
index 0000000000..f9695f6585
--- /dev/null
+++ b/lib/public/files/cache/iwatcher.php
@@ -0,0 +1,74 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCP\Files\Cache;
+
+/**
+ * check the storage backends for updates and change the cache accordingly
+ */
+interface IWatcher {
+	const CHECK_NEVER = 0; // never check the underlying filesystem for updates
+	const CHECK_ONCE = 1; // check the underlying filesystem for updates once every request for each file
+	const CHECK_ALWAYS = 2; // always check the underlying filesystem for updates
+
+	/**
+	 * @param int $policy either IWatcher::CHECK_NEVER, IWatcher::CHECK_ONCE, IWatcher::CHECK_ALWAYS
+	 */
+	public function setPolicy($policy);
+
+	/**
+	 * @return int either IWatcher::CHECK_NEVER, IWatcher::CHECK_ONCE, IWatcher::CHECK_ALWAYS
+	 */
+	public function getPolicy();
+
+	/**
+	 * check $path for updates and update if needed
+	 *
+	 * @param string $path
+	 * @param ICacheEntry|null $cachedEntry
+	 * @return boolean true if path was updated
+	 */
+	public function checkUpdate($path, $cachedEntry = null);
+
+	/**
+	 * Update the cache for changes to $path
+	 *
+	 * @param string $path
+	 * @param ICacheEntry $cachedData
+	 */
+	public function update($path, $cachedData);
+
+	/**
+	 * Check if the cache for $path needs to be updated
+	 *
+	 * @param string $path
+	 * @param ICacheEntry $cachedData
+	 * @return bool
+	 */
+	public function needsUpdate($path, $cachedData);
+
+	/**
+	 * remove deleted files in $path from the cache
+	 *
+	 * @param string $path
+	 */
+	public function cleanFolder($path);
+}
diff --git a/lib/public/files/storage.php b/lib/public/files/storage.php
index 063455a270..e59cecbdf7 100644
--- a/lib/public/files/storage.php
+++ b/lib/public/files/storage.php
@@ -37,6 +37,7 @@ use OCP\Files\Cache\ICache;
 use OCP\Files\Cache\IPropagator;
 use OCP\Files\Cache\IScanner;
 use OCP\Files\Cache\IUpdater;
+use OCP\Files\Cache\IWatcher;
 use OCP\Files\InvalidPathException;
 use OCP\Lock\ILockingProvider;
 
@@ -492,4 +493,9 @@ interface Storage {
 	 * @return IUpdater
 	 */
 	public function getUpdater();
+
+	/**
+	 * @return IWatcher
+	 */
+	public function getWatcher();
 }