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|
(* $I1: Unison file synchronizer: src/lock.ml $ *)
(* $I2: Last modified by vouillon on Fri, 05 Nov 2004 10:12:27 -0500 $ *)
(* $I3: Copyright 1999-2004 (see COPYING for details) $ *)
let rename oldFile newFile =
begin try Unix.link oldFile newFile with Unix.Unix_error _ -> () end;
let res = try (Unix.LargeFile.stat oldFile).Unix.LargeFile.st_nlink = 2
with Unix.Unix_error _ -> false
in
Unix.unlink oldFile;
res
let flags = [Unix.O_WRONLY; Unix.O_CREAT; Unix.O_EXCL]
let create name mode =
try
Unix.close (Unix.openfile name flags mode);
true
with Unix.Unix_error (Unix.EEXIST, _, _) ->
false
let rec unique name i mode =
let nm = name ^ string_of_int i in
if create nm mode then nm else
(* highly unlikely *)
unique name (i + 1) mode
let acquire name =
Util.convertUnixErrorsToTransient
"Lock.acquire"
(fun () ->
match Util.osType with
`Unix -> (* O_EXCL is broken under NFS... *)
rename (unique name (Unix.getpid ()) 0o600) name
| _ ->
create name 0o600)
let release name = try Unix.unlink name with Unix.Unix_error _ -> ()
let is_locked name =
Util.convertUnixErrorsToTransient
"Lock.test"
(fun () -> Sys.file_exists name)
|
