[gnome-chess] Fix crash on invalid clock type in pgn

[Sahil Sareen <ssareen src gnome org>]

commit e9d862cda33920c54254e32727319715531efcd9
Author: Sahil Sareen <sahil sareen hotmail com>
Date:   Sat Mar 14 21:04:16 2015 +0530

    Fix crash on invalid clock type in pgn
    
    Use a simple clock for invalid clock types in pgn.

 lib/chess-clock.vala |    5 +++--
 lib/chess-pgn.vala   |   16 +++++++++++++++-
 2 files changed, 18 insertions(+), 3 deletions(-)
---
diff --git a/lib/chess-clock.vala b/lib/chess-clock.vala
index 0bb3854..df38fe6 100644
--- a/lib/chess-clock.vala
+++ b/lib/chess-clock.vala
@@ -14,7 +14,8 @@ public enum ClockType
 {
     SIMPLE,
     FISCHER,
-    BRONSTEIN;
+    BRONSTEIN,
+    INVALID;
 
     public string to_string ()
     {
@@ -42,7 +43,7 @@ public enum ClockType
         case "bronstein":
             return BRONSTEIN;
         default:
-            assert_not_reached ();
+            return INVALID;
         }
     }
 }
diff --git a/lib/chess-pgn.vala b/lib/chess-pgn.vala
index 51e364f..cfe1fb4 100644
--- a/lib/chess-pgn.vala
+++ b/lib/chess-pgn.vala
@@ -235,6 +235,20 @@ enum State
 public class PGN : Object
 {
     public List<PGNGame> games;
+    private void insert_tag (PGNGame game, string tag_name, string tag_value)
+    {
+        switch (tag_name)
+        {
+        case "X-GNOME-ClockType":
+            if (ClockType.string_to_enum (tag_value) == ClockType.INVALID)
+            {
+                warning ("Invalid clock type in PGN: %s, using a simple clock.", tag_value);
+                tag_value = "simple";
+            }
+            break;
+        }
+        game.tags.insert (tag_name, tag_value);
+    }
 
     public PGN.from_string (string data) throws PGNError
     {
@@ -389,7 +403,7 @@ public class PGN : Object
                     continue;
                 else if (c == ']')
                 {
-                    game.tags.insert (tag_name, tag_value.str);
+                    insert_tag (game, tag_name, tag_value.str);
                     state = State.TAGS;
                 }
                 else