unikernel/duniverse/bos/test/watch.ml

@@ -0,0 +1,78 @@
+(*---------------------------------------------------------------------------
+   Copyright (c) 2015 The bos programmers. All rights reserved.
+   Distributed under the ISC license, see terms at the end of the file.
+  ---------------------------------------------------------------------------*)
+
+open Bos_setup
+
+(* Watch a directory for changes. First run will create a database
+   watchdb in the directory with modification times. Subsquent runs
+   will check files against that database. *)
+
+module Db = struct
+  let db_file = Fpath.v "watchdb"
+  let exists () = OS.File.exists db_file
+  let scan () =             (* returns list of (path, modification time) *)
+    let add p acc =
+      (OS.Path.stat p >>= fun stats ->
+       if stats.Unix.st_kind <> Unix.S_REG then Ok acc else
+       Ok ((p, stats.Unix.st_mtime) :: acc))
+      |> Logs.on_error_msg ~use:(fun _ -> acc)
+    in
+    Logs.app (fun m -> m "Scanning files");
+    OS.Dir.current () >>= fun dir ->
+    OS.Dir.fold_contents ~dotfiles:true ~elements:`Files add [] dir
+
+  let dump oc db = Ok (Marshal.(to_channel oc db [No_sharing; Compat_32]))
+  let slurp ic () = (Marshal.from_channel ic : float Fpath.Map.t)
+
+  let create files =
+    Logs.app (fun m -> m "Writing modification time database %a"
+                 Fpath.pp db_file);
+    let count = ref 0 in
+    let add acc (f, time) = incr count; Fpath.Map.add f time acc in
+    let db = List.fold_left add Fpath.Map.empty files in
+    R.join @@ OS.File.with_oc db_file dump db >>= fun () -> Ok !count
+
+  let check files =
+    let count = ref 0 in
+    let changes db (f, time) = match (incr count; Fpath.Map.find f db) with
+    | None ->
+        Logs.app (fun m -> m "New file: %a" Fpath.pp f)
+    | Some stamp when stamp <> time ->
+        Logs.app (fun m -> m "File changed: %a" Fpath.pp f)
+    | _ -> ()
+    in
+    Logs.app (fun m -> m "Checking against %a" Fpath.pp db_file);
+    OS.File.with_ic db_file slurp ()
+    >>= fun db -> List.iter (changes db) files; Ok !count
+end
+
+let watch () =
+  Db.scan ()
+  >>= fun files -> Db.exists ()
+  >>= fun exists -> if exists then Db.check files else Db.create files
+
+let main () =
+  let c = Mtime_clock.counter () in
+  let count = watch () |> Logs.on_error_msg ~use:(fun _ -> 0) in
+  Logs.app (fun m -> m "Watch completed for %d files in %a"
+               count Mtime.Span.pp (Mtime_clock.count c))
+
+let () = main ()
+
+(*---------------------------------------------------------------------------
+   Copyright (c) 2015 The bos programmers
+
+   Permission to use, copy, modify, and/or distribute this software for any
+   purpose with or without fee is hereby granted, provided that the above
+   copyright notice and this permission notice appear in all copies.
+
+   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+   WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+   MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+   ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+  ---------------------------------------------------------------------------*)