[gnome-software] Enforce that the GsAppKind gets set to sane values

[Richard Hughes <rhughes src gnome org>]

commit 173d1c76de668b546ba10ddad89ada96f29c773f
Author: Richard Hughes <richard hughsie com>
Date:   Tue Sep 10 09:58:56 2013 +0100

    Enforce that the GsAppKind gets set to sane values

 src/gs-app.c |   51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 50 insertions(+), 1 deletions(-)
---
diff --git a/src/gs-app.c b/src/gs-app.c
index c52f84b..415a9a7 100644
--- a/src/gs-app.c
+++ b/src/gs-app.c
@@ -316,12 +316,61 @@ gs_app_get_kind (GsApp *app)
 
 /**
  * gs_app_set_kind:
+ *
+ * This sets the kind of the application. The following state diagram explains
+ * the typical states. All applications start with kind %GS_APP_KIND_UNKNOWN.
+ *
+ * PACKAGE --> NORMAL
+ * PACKAGE --> SYSTEM
+ * NORMAL  --> SYSTEM
  */
 void
 gs_app_set_kind (GsApp *app, GsAppKind kind)
 {
+       gboolean state_change_ok = FALSE;
+       GsAppPrivate *priv = app->priv;
+
        g_return_if_fail (GS_IS_APP (app));
-       app->priv->kind = kind;
+       if (priv->kind == kind)
+               return;
+
+       /* check the state change is allowed */
+       switch (priv->kind) {
+       case GS_APP_KIND_UNKNOWN:
+               /* unknown can go into any state */
+               state_change_ok = TRUE;
+               break;
+       case GS_APP_KIND_PACKAGE:
+               /* package can become either normal or a system application */
+               if (kind == GS_APP_KIND_NORMAL ||
+                   kind == GS_APP_KIND_SYSTEM)
+                       state_change_ok = TRUE;
+               break;
+       case GS_APP_KIND_NORMAL:
+               /* normal can only be promoted to system */
+               if (kind == GS_APP_KIND_SYSTEM)
+                       state_change_ok = TRUE;
+               break;
+       case GS_APP_KIND_SYSTEM:
+       case GS_APP_KIND_OS_UPDATE:
+               /* this can never change state */
+               break;
+       default:
+               g_warning ("kind %s unhandled",
+                          gs_app_kind_to_string (priv->kind));
+               g_assert_not_reached ();
+       }
+
+       /* this state change was unexpected */
+       if (!state_change_ok) {
+               g_warning ("Kind change on %s from %s to %s is not OK",
+                          priv->id,
+                          gs_app_kind_to_string (priv->kind),
+                          gs_app_kind_to_string (kind));
+               return;
+       }
+
+       priv->kind = kind;
 }
 
 /**