From a65ad526202e5abd0c5e41e364fbe263350d7858 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gr=C3=A9goire=20Henry?= <gregoire.henry@ocamlpro.com>
Date: Mon, 23 Jan 2017 11:09:39 +0100
Subject: [PATCH] Shell: improve `Lwt_utils`

---
 src/utils/lwt_utils.ml  | 16 ++++++++++------
 src/utils/lwt_utils.mli |  2 ++
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/utils/lwt_utils.ml b/src/utils/lwt_utils.ml
index 00f857ab9..ceb472d13 100644
--- a/src/utils/lwt_utils.ml
+++ b/src/utils/lwt_utils.ml
@@ -346,12 +346,14 @@ let remove_dir dir =
     Lwt.return ()
 
 let rec create_dir ?(perm = 0o755) dir =
-  if Sys.file_exists dir then
-    Lwt.return ()
-  else begin
-    create_dir (Filename.dirname dir) >>= fun () ->
-    Lwt_unix.mkdir dir perm
-  end
+  Lwt_unix.file_exists dir >>= function
+  | false ->
+      create_dir (Filename.dirname dir) >>= fun () ->
+      Lwt_unix.mkdir dir perm
+  | true ->
+      Lwt_unix.stat dir >>= function
+      | {st_kind = S_DIR} -> Lwt.return_unit
+      | _ -> failwith "Not a directory"
 
 let create_file ?(perm = 0o644) name content =
   Lwt_unix.openfile name Unix.([O_TRUNC; O_CREAT; O_WRONLY]) perm >>= fun fd ->
@@ -402,4 +404,6 @@ let with_timeout ?(canceler = Canceler.create ()) timeout f =
       Canceler.cancel canceler >>= fun () ->
       fail Timeout
 
+let unless cond f =
+  if cond then Lwt.return () else f ()
 
diff --git a/src/utils/lwt_utils.mli b/src/utils/lwt_utils.mli
index 78cf995a2..14f48cf90 100644
--- a/src/utils/lwt_utils.mli
+++ b/src/utils/lwt_utils.mli
@@ -67,3 +67,5 @@ val with_timeout:
   ?canceler:Canceler.t ->
   float -> (Canceler.t -> 'a tzresult Lwt.t) -> 'a tzresult Lwt.t
 
+val unless: bool -> (unit -> unit Lwt.t) -> unit Lwt.t
+