(***********************************************************************)
(*                                                                     *)
(*                           Objective Caml                            *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the Q Public License version 1.0.               *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

(* "Expunge" a toplevel by removing compiler modules from the global List.map.
   Usage: expunge <source file> <dest file> <names of modules to keep> *)

open Sys
open Misc

module StringSet =
  Set.Make(struct
    type t = string
    let compare = compare
  end)

let to_keep = ref StringSet.empty

let expunge_map tbl =
  Symtable.filter_global_map
    (fun id -> StringSet.mem (Ident.name id) !to_keep)
    tbl

let expunge_crcs tbl =
  List.filter (fun (unit, crc) -> StringSet.mem unit !to_keep) tbl

let main () =
  let input_name = Sys.argv.(1) in
  let output_name = Sys.argv.(2) in
  Array.iter
    (fun exn -> to_keep := StringSet.add exn !to_keep)
    Runtimedef.builtin_exceptions;
  for i = 3 to Array.length Sys.argv - 1 do
    to_keep := StringSet.add (String.capitalize Sys.argv.(i)) !to_keep
  done;
  let ic = open_in_bin input_name in
  Bytesections.read_toc ic;
  let toc = Bytesections.toc() in
  let pos_first_section = Bytesections.pos_first_section ic in
  if Sys.os_type = "MacOS" then begin
    (* Create output as a text file for bytecode scripts *)
    let c = open_out_gen [Open_wronly; Open_creat] 0o777 output_name in
    close_out c
  end;
  let oc =
    open_out_gen [Open_wronly; Open_creat; Open_trunc; Open_binary] 0o777
                 output_name in
  (* Copy the file up to the symbol section as is *)
  seek_in ic 0;
  copy_file_chunk ic oc pos_first_section;
  (* Copy each section, modifying the symbol section in passing *)
  Bytesections.init_record oc;
  List.iter
    (fun (name, len) ->
      begin match name with
        "SYMB" ->
          let global_map = (input_value ic : Symtable.global_map) in
          output_value oc (expunge_map global_map)
      | "CRCS" ->
          let crcs = (input_value ic : (string * Digest.t) list) in
          output_value oc (expunge_crcs crcs)
      | _ ->
          copy_file_chunk ic oc len
      end;
      Bytesections.record oc name)
    toc;
  (* Rewrite the toc and trailer *)
  Bytesections.write_toc_and_trailer oc;
  (* Done *)
  close_in ic;
  close_out oc

let _ = Printexc.catch main (); exit 0