ocaml/otherlibs/labltk/support/fileevent.ml

(*************************************************************************)
(*                                                                       *)
(*                Objective Caml LablTk library                          *)
(*                                                                       *)
(*         Francois Rouaix, Francois Pessaux and Jun Furuse              *)
(*               projet Cristal, INRIA Rocquencourt                      *)
(*            Jacques Garrigue, Kyoto University RIMS                    *)
(*                                                                       *)
(*   Copyright 1999 Institut National de Recherche en Informatique et    *)
(*   en Automatique and Kyoto University.  All rights reserved.          *)
(*   This file is distributed under the terms of the GNU Library         *)
(*   General Public License, with the special exception on linking       *)
(*   described in file ../../../LICENSE.                                 *)
(*                                                                       *)
(*************************************************************************)

(* $Id$ *)

open Unix
open Support
open Protocol

external add_file_input : file_descr -> cbid -> unit
        =  "camltk_add_file_input"
external rem_file_input : file_descr -> unit
        =  "camltk_rem_file_input"
external add_file_output : file_descr -> cbid -> unit
        =  "camltk_add_file_output"
external rem_file_output : file_descr -> unit
        =  "camltk_rem_file_output"

(* File input handlers *)

let fd_table = Hashtbl.create 37 (* Avoid space leak in callback table *)

let add_fileinput ~fd ~callback:f =
  let id = new_function_id () in
  Hashtbl'.add callback_naming_table ~key:id ~data:(fun _ -> f());
  Hashtbl'.add fd_table ~key:(fd, 'r') ~data:id;
  if !Protocol.debug then begin
    Protocol.prerr_cbid id; prerr_endline " for fileinput"
  end;
  add_file_input fd id

let remove_fileinput ~fd =
  try
    let id = Hashtbl.find fd_table (fd, 'r') in
    clear_callback id;
    Hashtbl.remove fd_table (fd, 'r');
    if !Protocol.debug then begin
      prerr_string "clear "; 
      Protocol.prerr_cbid id;
      prerr_endline " for fileinput"
    end;
    rem_file_input fd
  with
    Not_found -> ()

let add_fileoutput ~fd ~callback:f =
  let id = new_function_id () in
  Hashtbl'.add callback_naming_table ~key:id ~data:(fun _ -> f());
  Hashtbl'.add fd_table ~key:(fd, 'w') ~data:id;
  if !Protocol.debug then begin
    Protocol.prerr_cbid id; prerr_endline " for fileoutput"
  end;
  add_file_output fd id

let remove_fileoutput ~fd =
  try
    let id = Hashtbl.find fd_table (fd, 'w') in
    clear_callback id;
    Hashtbl.remove fd_table (fd, 'w');
    if !Protocol.debug then begin
      prerr_string "clear "; 
      Protocol.prerr_cbid id;
      prerr_endline " for fileoutput"
    end;
    rem_file_output fd
  with
    Not_found -> ()