X-Git-Url: https://git.hcoop.net/hcoop/domtool2.git/blobdiff_plain/d5772aa364d60b3a005443b07db58672d64b0432..991d8e6619bc9ff2182a39cfbeead53bee768a99:/src/plugins/apt.sml

diff --git a/src/plugins/apt.sml b/src/plugins/apt.sml
index d2517e9..e97ec82 100644
--- a/src/plugins/apt.sml
+++ b/src/plugins/apt.sml
@@ -22,6 +22,31 @@ structure Apt :> APT = struct
 
 fun validName s = CharVector.all (fn ch => Char.isAlphaNum ch orelse ch = #"_" orelse ch = #"-" orelse ch = #".") s
 		  andalso (size s > 0 andalso String.sub (s, 0) <> #"-")
+
+(* Copyed from the portal, doesn't exactly go out this in the most
+   direct way, or does it? *)
+
+fun exists name =
+    validName name andalso let
+	val proc = Unix.execute ("/usr/bin/apt-cache", ["show", name])
+	val inf = Unix.textInstreamOf proc
+
+	val _ = TextIO.inputLine inf (* in every let* lies an imperative program in disguise *)
+
+	fun loop _ =
+	    case TextIO.inputLine inf of
+		NONE => false
+	      | SOME line =>
+		if size line >= 9 andalso String.substring (line, 0, 9) = "Section: " then
+		    true
+		else if size line >= 13 andalso String.substring (line, 0, 13) = "Description: " then
+		    false
+		else
+		    loop ()
+    in
+	loop ()
+	before ignore (Unix.reap proc)
+    end
 			   
 fun installed name =
     validName name