added OC_FILESYSTEM::hash()

syntax is the same has http://www.php.net/manual/en/function.hash-file.php

lib/filestorage.php

@@ -73,6 +73,7 @@ class OC_FILESTORAGE{
 	public function delTree($path){}
 	public function find($path){}
 	public function getTree($path){}
+	public function hash($type,$path,$raw){}
 }
 
 
@@ -428,5 +429,12 @@ class OC_FILESTORAGE_LOCAL extends OC_FILESTORAGE{
 		}
 		return $tree;
 	}
+
+	public function hash($type,$path,$raw){
+		if($return=hash_file($type,$this->datadir.$path,$raw)){
+			$this->notifyObservers($path,OC_FILEACTION_READ);
+		}
+		return $return;
+	}
 }
 ?>
\ No newline at end of file

lib/filesystem.php

@@ -376,5 +376,10 @@ class OC_FILESYSTEM{
 			return $return;
 		}
 	}
+	static public function hash($type,$path,$raw=false){
+		if(self::canRead($path) and $storage=self::getStorage($path)){
+			return $storage->hash($type,self::getInternalPath($path),$raw);
+		}
+	}
 }
 ?>