[Libguestfs] [PATCH 1/2] mllib: add an hook to cleanup directories on exit

[Richard W.M. Jones]

[Adding libguestfs CC this time]

On Thu, Feb 20, 2014 at 03:04:19PM +0100, Pino Toscano wrote:
> Much similar to unlink_on_exit, but recursively cleaning directories.
> ---
>  mllib/common_utils.ml | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
> index 3943417..d02a2d3 100644
> --- a/mllib/common_utils.ml
> +++ b/mllib/common_utils.ml
> @@ -386,6 +386,41 @@ let unlink_on_exit =
>        registered_handlers := true
>      )
>  
> +(* Remove a temporary directory on exit. *)
> +let rmdir_on_exit =
> +  let dirs = ref [] in
> +  let registered_handlers = ref false in
> +
> +  let rec unlink_dirs () =
> +    let rec recursive_rmdir fn =
> +      match (Unix.lstat fn).Unix.st_kind with
> +      | Unix.S_DIR ->
> +        let names = Array.map (fun d -> fn // d) (Sys.readdir fn) in
> +        Array.iter recursive_rmdir names;
> +        Unix.rmdir fn
> +      | Unix.S_REG
> +      | Unix.S_CHR
> +      | Unix.S_BLK
> +      | Unix.S_LNK
> +      | Unix.S_FIFO
> +      | Unix.S_SOCK ->
> +        Unix.unlink fn
> +    in
> +    List.iter (
> +      fun dir -> try recursive_rmdir dir with _ -> ()
> +    ) !dirs
> +  and register_handlers () =
> +    (* Remove on exit. *)
> +    at_exit unlink_dirs
> +  in
> +
> +  fun dir ->
> +    dirs := dir :: !dirs;
> +    if not !registered_handlers then (
> +      register_handlers ();
> +      registered_handlers := true
> +    )
> +

This is really very complicated compared to:

    let cmd = sprintf "rm -rf %s" (Filename.quote tmpdir) in
    ignore (Sys.command cmd));

It's also not likely to be as well debugged as coreutils, which has
been working on multiple platforms for 25 years or so.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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