(******************************************************************************)

(*  ocaml-fileutils: files and filenames common operations                    *)

(*                                                                            *)

(*  Copyright (C) 2003-2014, Sylvain Le Gall                                  *)

(*                                                                            *)

(*  This library is free software; you can redistribute it and/or modify it   *)

(*  under the terms of the GNU Lesser General Public License as published by  *)

(*  the Free Software Foundation; either version 2.1 of the License, or (at   *)

(*  your option) any later version, with the OCaml static compilation         *)

(*  exception.                                                                *)

(*                                                                            *)

(*  This library 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 file         *)

(*  COPYING for more details.                                                 *)

(*                                                                            *)

(*  You should have received a copy of the GNU Lesser General Public License  *)

(*  along with this library; if not, write to the Free Software Foundation,   *)

(*  Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA             *)

(******************************************************************************)

open FileUtilMisc

exception UmaskError of string

type umask_error = [ `Exc of exn | `NoStickyBit of int ]

let umask

      ?(error=(fun str _ -> raise (UmaskError str)))

      ?mode out =

  let handle_error, handle_exception =

    handle_error_gen "umask" error

      (function

       | `NoStickyBit i ->

           Printf.sprintf "Cannot set sticky bit in umask 0o%04o" i

       | #exc -> "")

  in

  let complement i = 0o0777 land (lnot i) in

  let try_umask i =

    try

      Unix.umask i

    with e ->

      handle_exception ~fatal:true e;

      raise e

  in

  let get () =

    let cmask = try_umask 0o777 in

    let _mask: int = try_umask cmask in

    cmask

  in

  let set i =

    let eff_i = i land 0o777 in

    let _i: int =

      if i <> eff_i then

        handle_error ~fatal:true (`NoStickyBit i);

      try_umask eff_i

    in

    eff_i

  in

  let v =

    match mode with

    | Some (`Symbolic s) ->

        let v = get () in

          set

            (complement

               (FileUtilMode.apply ~is_dir:false ~umask:0 (complement v) s))

    | Some (`Octal i) -> set i

    | None -> get ()

  in

  match out with

    | `Symbolic f -> f (FileUtilMode.of_int (0o0777 land (lnot v)))

    | `Octal f -> f v

let umask_apply m = m land (lnot (umask (`Octal (fun i -> i))))