Update lib/filestorage/common.php

Added function to clean a path

lib/filestorage/common.php

@@ -288,4 +288,28 @@ abstract class OC_Filestorage_Common extends OC_Filestorage {
 	public function getOwner($path) {
 		return OC_User::getUser();
 	}
+	
+	/**
+	 * clean a path, i.e. remove all redundant '.' and '..'
+	 * making sure that it can't point to higher than '/'
+	 * @param $path The path to clean
+	 * @return string cleaned path
+	 */
+	public function cleanPath($path) {
+		if (strlen($path) == 0 or $path[0] != '/') {
+			$path = '/' . $path;
+		}
+		
+		$chunks = explode('/', $path);
+		$output = array();
+		foreach ($chunks as $chunk) {
+			if ($chunk == '..') {
+				array_pop($output);
+			} else if ($chunk == '.') {
+			} else {
+				$output[] = $chunk;
+			}
+		}
+		return implode('/', $output);
+	}
 }