[gnome-games] playstation: Add PlayStationHeader.is_a_disc_id()

[Adrien Plazas <aplazas src gnome org>]

commit c81da85ecf4c596d7d9548471245071770d769ce
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Sun Aug 28 09:27:33 2016 +0200

    playstation: Add PlayStationHeader.is_a_disc_id()
    
    This allows to be more sure we found a valid disc ID and hence that the
    header is valid.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=770470

 plugins/playstation/src/playstation-header.vala |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/plugins/playstation/src/playstation-header.vala b/plugins/playstation/src/playstation-header.vala
index ae02b3b..762b824 100644
--- a/plugins/playstation/src/playstation-header.vala
+++ b/plugins/playstation/src/playstation-header.vala
@@ -8,6 +8,9 @@ private class Games.PlayStationHeader : Object {
        private const string BOOT_MAGIC_VALUE = "BOOT";
 
        private const string[] IDS = { "SLUS", "SCUS", "SLES", "SCES", "SLPS", "SLPM", "SCPS" };
+       private const size_t DISC_ID_SIZE = 10;
+
+       private static Regex disc_id_regex;
 
        private string _disc_id;
        public string disc_id {
@@ -49,7 +52,8 @@ private class Games.PlayStationHeader : Object {
                        raw_id = raw_id.replace (".", "");
                        raw_id = (id + raw_id).up ();
 
-                       return raw_id;
+                       if (is_a_disc_id (raw_id))
+                               return raw_id;
                }
 
                return null;
@@ -64,4 +68,11 @@ private class Games.PlayStationHeader : Object {
 
                return null;
        }
+
+       private static bool is_a_disc_id (string disc_id) {
+               if (disc_id_regex == null)
+                       disc_id_regex = /[A-Z]{4}-\d{5}/;
+
+               return disc_id_regex.match (disc_id);
+       }
 }