Re: [Libguestfs] [PATCH common 2/4] mltools: Reimplement On_exit to use a list of actions

Previously we used separate lists of files, dirs, pids, etc. This makes it harder to introduce new features to reorder actions. Reimplement the module so we use a simple list of actions, where each action can have type File, Rm_rf, Kill, etc. Iterate through this list on exit to execute the actions. The actions will run in a different order from before, but we didn't guarantee the ordering before. Apart from that the functionality is unchanged. --- mltools/on_exit.ml | 48 ++++++++++++++++++++++------------------------ 1 file changed, 23 insertions(+), 25 deletions(-) diff --git a/mltools/on_exit.ml b/mltools/on_exit.ml index 9cdc496..4fa2c3b 100644 --- a/mltools/on_exit.ml +++ b/mltools/on_exit.ml @@ -23,23 +23,29 @@ open Common_gettext.Gettext open Unix open Printf -(* List of files to unlink. *) -let files = ref [] +type action = + | Unlink of string (* filename *) + | Rm_rf of string (* directory *) + | Kill of int * int (* signal, pid *) + | Fn of (unit -> unit) (* generic function *) -(* List of directories to remove. *) -let rmdirs = ref [] - -(* List of PIDs to kill. *) -let kills = ref [] - -(* List of functions to call. *) -let fns = ref [] +(* List of actions. *) +let actions = ref [] (* Perform a single exit action, printing any exception but * otherwise ignoring failures. *) -let do_action f arg = - try f arg with exn -> debug "%s" (Printexc.to_string exn) +let do_action action = + try + match action with + | Unlink file -> Unix.unlink file + | Rm_rf dir -> + let cmd = sprintf "rm -rf %s" (Filename.quote dir) in

+ ignore (Tools_utils.shell_command cmd) + | Kill (signal, pid) -> + kill pid signal + | Fn f -> f () + with exn -> debug "%s" (Printexc.to_string exn) (* Make sure the actions are performed only once. *) let done_actions = ref false @@ -47,15 +53,7 @@ let done_actions = ref false (* Perform the exit actions. *) let do_actions () = if not !done_actions then ( - List.iter (do_action (fun f -> f ())) !fns; - List.iter (do_action (fun (signal, pid) -> kill pid signal)) !kills; - List.iter (do_action (fun file -> Unix.unlink file)) !files; - List.iter (do_action ( - fun dir -> - let cmd = sprintf "rm -rf %s" (Filename.quote dir) in - ignore (Tools_utils.shell_command cmd) - ) - ) !rmdirs; + List.iter do_action !actions ); done_actions := true @@ -96,16 +94,16 @@ let register () = let f fn = register (); - List.push_front fn fns + List.push_front (Fn fn) actions let unlink filename = register (); - List.push_front filename files + List.push_front (Unlink filename) actions let rm_rf dir = register (); - List.push_front dir rmdirs + List.push_front (Rm_rf dir) actions let kill ?(signal = Sys.sigterm) pid = register (); - List.push_front (signal, pid) kills + List.push_front (Kill (signal, pid)) actions