src/plugins/apt.sml

   1 (* HCoop Domtool (http://hcoop.sourceforge.net/)
   2  * Copyright (c) 2006-2007, Adam Chlipala
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *)
  18
  19 (* APT package database querying *)
  20
  21 structure Apt :> APT = struct
  22
  23 fun validName s = CharVector.all (fn ch => Char.isAlphaNum ch orelse ch = #"_" orelse ch = #"-" orelse ch = #".") s
  24                   andalso (size s > 0 andalso String.sub (s, 0) <> #"-")
  25
  26 (* Copyed from the portal, doesn't exactly go out this in the most
  27    direct way, or does it? *)
  28
  29 fun exists name =
  30     validName name andalso let
  31         val proc = Unix.execute ("/usr/bin/apt-cache", ["show", name])
  32         val inf = Unix.textInstreamOf proc
  33
  34         val _ = TextIO.inputLine inf (* in every let* lies an imperative program in disguise *)
  35
  36         fun loop _ =
  37             case TextIO.inputLine inf of
  38                 NONE => false
  39               | SOME line =>
  40                 if size line >= 9 andalso String.substring (line, 0, 9) = "Section: " then
  41                     true
  42                 else if size line >= 13 andalso String.substring (line, 0, 13) = "Description: " then
  43                     false
  44                 else
  45                     loop ()
  46     in
  47         loop ()
  48         before ignore (Unix.reap proc)
  49     end
  50
  51 fun installed name =
  52     validName name
  53     andalso let
  54         val proc = Unix.execute ("/usr/bin/apt-cache", ["policy", name])
  55         val inf = Unix.textInstreamOf proc
  56
  57         val _ = TextIO.inputLine inf
  58     in
  59         (case TextIO.inputLine inf of
  60              NONE => false
  61            | SOME line =>
  62              case String.tokens Char.isSpace line of
  63                  [_, "(none)"] => false
  64                | [_, _] => true
  65                | _ => false)
  66         before ignore (Unix.reap proc)
  67     end
  68
  69 end