Merge pull request #628 from talex5/rmtree

Add Path.rmtree ?missing_ok and allow non-directories

Author: talex5

lib_eio/path.ml

@@ -165,18 +165,30 @@ let rmdir t =
     let bt = Printexc.get_raw_backtrace () in
     Exn.reraise_with_context ex bt "removing directory %a" pp t
 
-let rec rmtree (t : Fs.dir_ty t) =
-  with_open_dir t (fun t ->
-      read_dir t |> List.iter (fun name ->
-          let item = t / name in
-          match kind ~follow:false item with
-          | `Directory -> rmtree item
-          | _ -> unlink item
-        )
+let catch_missing ~missing_ok fn x =
+  if missing_ok then
+    try fn x
+    with Exn.Io (Fs.E Not_found _, _) -> ()
+  else fn x
+
+let rec rmtree ~missing_ok t =
+  match kind ~follow:false t with
+  | `Directory ->
+    Switch.run (fun sw ->
+        match
+          let t = open_dir ~sw t in
+          t, read_dir t
+        with
+        | t, items -> List.iter (fun x -> rmtree ~missing_ok (t / x)) items
+        | exception Exn.Io (Fs.E Not_found _, _) when missing_ok -> ()
     );
-  rmdir t
+    catch_missing ~missing_ok rmdir t
+  | `Not_found when missing_ok -> ()
+  | _ ->
+    catch_missing ~missing_ok unlink t
 
-let rmtree = (rmtree : Fs.dir_ty t -> unit :> [> Fs.dir_ty] t -> unit)
+let rmtree ?(missing_ok=false) t =
+  rmtree ~missing_ok (t :> Fs.dir_ty t)
 
 let rename t1 t2 =
   let (dir2, new_path) = t2 in

lib_eio/path.mli

@@ -192,8 +192,13 @@ val rmdir : _ t -> unit
 
     Note: this usually requires the directory to be empty. *)
 
-val rmtree : _ t -> unit
-(** [rmtree t] removes directory [t] and its contents, recursively. *)
+val rmtree : ?missing_ok:bool -> _ t -> unit
+(** [rmtree t] removes [t] (and its contents, recursively, if it's a directory).
+
+    @param missing_ok If [false] (the default), raise an {!Fs.Not_found} IO error if [t] doesn't exist.
+                      If [true], ignore missing items.
+                      This applies recursively, allowing two processes
+                      to attempt to remove a tree at the same time. *)
 
 val rename : _ t -> _ t -> unit
 (** [rename old_t new_t] atomically unlinks [old_t] and links it as [new_t].

tests/fs.md

@@ -61,8 +61,8 @@ let try_rmdir path =
   | () -> traceln "rmdir %a -> ok" Path.pp path
   | exception ex -> traceln "@[<h>%a@]" Eio.Exn.pp ex
 
-let try_rmtree path =
-  match Path.rmtree path with
+let try_rmtree ?missing_ok path =
+  match Path.rmtree ?missing_ok path with
   | () -> traceln "rmtree %a -> ok" Path.pp path
   | exception ex -> traceln "@[<h>%a@]" Eio.Exn.pp ex
 
@@ -413,9 +413,17 @@ Removing something that doesn't exist or is out of scope:
   try_write_file ~create:(`Exclusive 0o600) (foo / "bar/file1") "data";
   try_rmtree foo;
   assert (Path.kind ~follow:false foo = `Not_found);
+  traceln "A second rmtree is OK with missing_ok:";
+  try_rmtree ~missing_ok:true foo;
+  traceln "But not without:";
+  try_rmtree ~missing_ok:false foo;
 +mkdirs <cwd:foo/bar/baz> -> ok
 +write <cwd:foo/bar/file1> -> ok
 +rmtree <cwd:foo> -> ok
++A second rmtree is OK with missing_ok:
++rmtree <cwd:foo> -> ok
++But not without:
++Eio.Io Fs Not_found _, removing file <cwd:foo>
 - : unit = ()
 ```