148 lines
4.3 KiB
OCaml
148 lines
4.3 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Jerome Vouillon, projet Cristal, INRIA Rocquencourt *)
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(* Objective Caml port by John Malecki and Xavier Leroy *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(**************************** Input control ****************************)
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open Unix
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open Primitives
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(*** Actives files. ***)
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(* List of the actives files. *)
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let active_files =
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ref ([] : (file_descr * ((io_channel -> unit) * io_channel)) list)
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(* Add a file to the list of actives files. *)
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let add_file file controller =
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active_files := (file.io_fd, (controller, file))::!active_files
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(* Remove a file from the list of actives files. *)
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let remove_file file =
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active_files := assoc_remove !active_files file.io_fd
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(* Change the controller for the given file. *)
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let change_controller file controller =
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remove_file file; add_file file controller
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(* Return the controller currently attached to the given file. *)
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let current_controller file =
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fst (List.assoc file.io_fd !active_files)
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(* Execute a function with `controller' attached to `file'. *)
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(* ### controller file funct *)
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let execute_with_other_controller controller file funct =
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let old_controller = current_controller file in
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change_controller file controller;
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try
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let result = funct () in
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change_controller file old_controller;
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result
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with
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x ->
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change_controller file old_controller;
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raise x
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(*** The "Main Loop" ***)
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let continue_main_loop =
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ref true
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let exit_main_loop _ =
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continue_main_loop := false
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(* Handle active files until `continue_main_loop' is false. *)
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let main_loop () =
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let old_state = !continue_main_loop in
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try
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continue_main_loop := true;
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while !continue_main_loop do
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try
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let (input, _, _) =
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select (List.map fst !active_files) [] [] (-1.)
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in
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List.iter
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(function fd ->
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let (funct, iochan) = (List.assoc fd !active_files) in
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funct iochan)
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input
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with
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Unix_error (EINTR, _, _) -> ()
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done;
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continue_main_loop := old_state
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with
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x ->
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continue_main_loop := old_state;
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raise x
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(*** Managing user inputs ***)
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(* Are we in interactive mode ? *)
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let interactif = ref true
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let current_prompt = ref ""
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(* Where the user input come from. *)
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let user_channel = ref std_io
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let read_user_input buffer length =
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main_loop ();
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input !user_channel.io_in buffer 0 length
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(* Stop reading user input. *)
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let stop_user_input () =
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remove_file !user_channel
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(* Resume reading user input. *)
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let resume_user_input () =
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if not (List.mem_assoc !user_channel.io_fd !active_files) then begin
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if !interactif then begin
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print_string !current_prompt;
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flush Pervasives.stdout
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end;
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add_file !user_channel exit_main_loop
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end
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(* Ask user a yes or no question. *)
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let yes_or_no message =
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if !interactif then
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let old_prompt = !current_prompt in
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try
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current_prompt := message ^ " ? (y or n) ";
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let answer =
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let rec ask () =
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resume_user_input ();
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let line =
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string_trim (Lexer.line (Lexing.from_function read_user_input))
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in
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stop_user_input ();
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match (if String.length line > 0 then line.[0] else ' ') with
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'y' -> true
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| 'n' -> false
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| _ ->
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print_string "Please answer y or n.";
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print_newline ();
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ask ()
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in
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ask ()
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in
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current_prompt := old_prompt;
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answer
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with
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x ->
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current_prompt := old_prompt;
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stop_user_input ();
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raise x
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else
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false
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