bundles/menhirLib/menhir-20120123/demos/ocamldep.wrapper

   1 #!/usr/bin/env ocaml
   2
   3 (* ocamldep.wrapper <filename> ... <filename> - <ocamldep command>
   4    runs the <ocamldep command> in an environment where all of the
   5    <filenames> listed appear to exist. The files are created, if
   6    required, before the command is run, and destroyed afterwards. *)
   7
   8 (* An earlier version of this script acquired a lock, so as to prevent
   9    multiple instances of this script from interfering with one another.
  10    However, this did not prevent interference between this script and
  11    some other process (e.g., the ocaml compiler) which creates files.
  12    So, the lock has been removed. My suggestion is to never use this
  13    script in a concurrent setting. If you wish to use parallel make,
  14    then you might be able to use a two-level Makefile approach: first,
  15    compute all dependencies in a sequential manner; then, construct all
  16    targets in a parallel manner. *)
  17
  18 #load "unix.cma"
  19 open Printf
  20
  21 (* Parse the command line. The arguments that precede "-" are understood
  22    as file names and stored in the list [xs]. The arguments that follow
  23    "-" are understood as a command and stored in [command]. *)
  24
  25 let xs =
  26   ref []
  27
  28 let command =
  29   ref ""
  30
  31 let verbose =
  32   ref false
  33
  34 let rec loop accumulating i =
  35   if i = Array.length Sys.argv then
  36     ()
  37   else if accumulating then
  38     (* [accumulating] is [true] as long as we have not found the "-" marker *)
  39     match Sys.argv.(i) with
  40     | "-v" ->
  41         verbose := true;
  42         loop true (i+1)
  43     | "-" ->
  44         (* We have found the marker. The next parameter should be the name of
  45            the raw [ocamldep] command. Copy it to the command (unquoted --
  46            apparently some shells do not permit quoting a command name). *)
  47         let i = i + 1 in
  48         assert (i < Array.length Sys.argv);
  49         command := Sys.argv.(i);
  50         (* Stop accumulating file names. Copy the remaining arguments into
  51            the command. *)
  52         loop false (i+1)
  53     | _ ->
  54         (* Continue accumulating file names in [xs]. *)
  55         xs := Sys.argv.(i) :: !xs;
  56         loop true (i+1)
  57   else begin
  58     (* After we have found the "-" marker, the remaining arguments are
  59        copied (quoted) into the command. *)
  60     command := sprintf "%s %s" !command (Filename.quote Sys.argv.(i));
  61     loop false (i+1)
  62   end
  63
  64 let () =
  65   loop true 1
  66
  67 (* Create the required files if they don't exist, run the command,
  68    then destroy any files that we have created. *)
  69
  70 let rec loop = function
  71   | [] ->
  72       if !verbose then
  73         fprintf stderr "ocamldep.wrapper: running %s\n" !command;
  74       Sys.command !command
  75   | x :: xs ->
  76       if Sys.file_exists x then
  77         loop xs
  78       else begin
  79         if !verbose then
  80           fprintf stderr "ocamldep.wrapper: creating fake %s\n" x;
  81         let c = open_out x in
  82         close_out c;
  83         let exitcode = loop xs in
  84         if Sys.file_exists x then begin
  85           try
  86             if !verbose then
  87               fprintf stderr "ocamldep.wrapper: removing fake %s..." x;
  88             Sys.remove x;
  89             if !verbose then
  90               fprintf stderr " ok\n"
  91           with Sys_error _ ->
  92             if !verbose then
  93               fprintf stderr " failed\n"
  94         end;
  95         exitcode
  96       end
  97
  98 let () =
  99   exit (loop !xs)