New dispatch module

dispatch.ml

@@ -0,0 +1,125 @@
+type fd_handler = t -> event -> Unix.file_descr -> unit
+type timeout_handler = t -> float -> unit
+type timeout = (float * timeout_handler)
+
+module Fd_map = 
+    Map.Make (struct
+		type t = Unix.file_descr
+		let compare = compare
+	      )
+
+module Timeout_set =
+  Set.Make (struct
+	      type t = timeout
+	      let compare = compare
+	    )
+
+type event = Input | Priority | Output | Error | Hangup
+
+type t = {
+  e : Epoll.t;
+  fds : (fd_handler * event list) Fd_map.t ref;
+  numfds : int ref;
+  timeouts : timeout_handler Timeout_set.t ref;
+}
+
+let rec epoll_events_of_events 
+  | [] -> []
+  | Input :: tl -> Epoll.In @ (epoll_events_of_events tl)
+  | Priority :: tl -> Epoll.Priority @ (epoll_events_of_events tl)
+  | Output :: tl -> Epoll.Output @ (epoll_events_of_events tl)
+  | Error :: tl -> Epoll.Error @ (epoll_events_of_events tl)
+  | Hangup :: tl -> Epoll.Hangup @ (epoll_events_of_events tl)
+  
+let rec events_of_epoll_events
+  | [] -> []
+  | Epoll.In :: tl -> Input @ (events_of_epoll_events)
+  | Epoll.Priority :: tl -> Priority @ (events_of_epoll_events)
+  | Epoll.Out :: tl -> Out @ (events_of_epoll_events)
+  | Epoll.Error :: tl -> Error @ (events_of_epoll_events)
+  | Epoll.Hangup :: tl -> Hangup @ (events_of_epoll_events)
+
+let create size =
+  {e = Epoll.create size;
+   fds = ref Fd_map.empty;
+   numfds = ref 0;
+   timeouts = ref Timeout_set.empty}
+
+let destroy d =
+  Epoll.destroy d.e;
+  (* Explicitly unreference fds and timeouts, in case d sticks around *)
+  d.fds := Fd_map.empty;
+  d.numfds := 0;
+  d.timeouts := Timeout_set.empty
+
+let add d fd handler events =
+  Epoll.ctl d.e Epoll.Add (fd, (epoll_events_of_events events));
+  d.fds := Fd_map.add fd (handler, events) !d.fds;
+  d.numfds := !d.numfds + 1
+
+let modify d fd events =
+  Epoll.ctl d.e Epoll.Modify (fd, (epoll_events_of_events events))
+
+let set_handler d fd handler =
+  let (_, events) = Fd_map.find fd in
+    d.fds := Fd_map.add fd (handler, events) !d.fds
+
+let delete d fd =
+  Epoll.ctl d.e Epoll.Delete (fd, []);
+  d.fds := Fd_map.remove fd !d.fds;
+  d.numfds := !d.numfds - 1
+
+let add_timeout d time handler =
+  d.timeouts := Timeout_set.add (time, handler) !d.timeouts
+
+let delete d time =
+  let may_remain (time', _) = 
+    time' <> time 
+  in
+  d.timeouts := Timeout_set.filter may_remain !d.timeouts
+
+
+let rec dispatch_timeouts d now =
+  let (time, handler) = Timeout_set.min_elt !d.timeouts in
+    if now > time then
+      ()
+    else begin
+      handler d time;
+      d.timeouts := Timeout_set.remove time !d.timeouts;
+      dispatch_timeouts d now
+    end
+
+let rec dispatch_events d events_list =
+  match events_list with
+    | [] ->
+	()
+    | (fd, epoll_events) :: tl ->
+	let handler = Fd_map.find fd !d.fds in
+	let events = events_of_epoll_events in
+	  handler d fd events;
+	  dispatch_events d tl
+
+let once d =
+  let now = Unix.time () in
+  let timeout =
+    try
+      let (time, _) = Timeout_set.min_elt !d.timeouts in
+      let timeout_s = max (time - now) 0.0 in
+	int_of_float (timeout_s *. 1000.0)
+    with Not_found ->
+      -1
+  in
+  let result = Epoll.wait d.e !d.nfds timeout in
+    dispatch_timeouts d (Unix.time ());
+    dispatch_events d result
+
+let rec run d =    
+  if ((!d.fds == Fd_map.empty) &&
+	(!d.timeouts == Timeout_set.empty)) then
+    ()
+  else begin
+    once d;
+    run d
+  end
+
+	

dispatch.mli

@@ -0,0 +1,49 @@
+type t
+(** The type of event dispatchers *)
+
+type event = Input | Priority | Output | Error | Hangup
+(** An event associated with a file descriptor *)
+
+type fd_handler = t -> event -> Unix.file_descr -> unit
+(** [fd_handler d evt fd] handles an [event] generated by dispatcher [d] *)
+
+type timeout_handler = t -> float -> unit
+(** [timeout_handler d when] is called at or after [when] by dispatcher [d] *)
+
+val create : [size] -> t
+(** Create a new event dispatcher, preallocating [size] fd events.  [size]
+    is just a hint, the fd list will grow on demand. *)
+
+val destroy : t -> unit
+(** Destroy an event dispatcher *)
+
+val add : t -> Unix.file_descr -> fd_handler -> event list -> unit
+(** [add d fd handler events] begins listening for [events] on file
+    descriptor [fd], calling [handler] when an event occurs. *)
+
+val modify : t -> Unix.file_descr -> event_list -> unit
+(** [modify d fd events] changes the events to listen for on fd *)
+
+val set_handler : t -> Unix.file_descr -> fd_handler -> unit
+(** [set_handler d fd handler] changes the handler to be invoked for
+    events on [fd] *)
+
+val delete : t -> Unix.file_descr -> unit
+(** [delete d fd] stops [d] paying attention to events on file
+    descriptor [fd] *)
+
+val add_timeout : t -> float -> timeout_handler -> unit
+(** [add_timeout d time handler] will cause dispatcher [d] to invoke
+    [handler d time] at or after [time] *)
+
+val delete_timeout : t -> float -> unit
+(** [delete_timeout d time] prevents dispatcher from invoking any
+    handlers added for [time] *)
+
+val once : t -> unit
+(** [once d] will dispatch one event (or set of simultaneous events)
+    added to [d]. *)
+
+val run : t -> unit
+(** [run d] will dispatch events from [d] until all file descriptors
+    have been removed and all timeouts have run or been removed *)

epoll.mli

@@ -1,7 +1,7 @@
 (*
  * OCaml epoll() interface
  * Author: Neale Pickett <neale@woozle.org>
- * Time-stamp: <2008-03-10 23:19:20 neale>
+ * Time-stamp: <2008-03-14 11:49:20 neale>
  *)
 
 (**
@@ -27,7 +27,7 @@ external ctl : t -> op -> (Unix.file_descr * event list) -> unit = "ocaml_epoll_
   (** Add, Modify, or Delete an event list *)
 
 external wait : t -> int -> int -> (Unix.file_descr * event list) list = "ocaml_epoll_wait"
-  (** Block on events
-   *
-   * Returns a list of file descriptors and a list of the events that happened.
-   *)
+(** [wait e maxevents timeout] returns a list of at most [maxevents]
+    (file descriptor * event list)s that occurred before at least
+    [timeout] milliseconds elapsed.
+ *)