From 538910f00b2346b66ccc1262a37b9904b10ac3f5 Mon Sep 17 00:00:00 2001
From: Derek Atkins <derek@ihtfp.com>
Date: Tue, 20 Dec 2011 21:12:22 +0000
Subject: [PATCH] Add a "features" table to the KVP frame, and pop up an error
 message if we find a feature we don't know about.  Currently there are no
 known features, so essentially we will error out if we see anything.

The format for the slots table is:

  Book Slots ->
      features (frame) ->
            <feature name> (string) -> <feature description>
            ...

The feature description is printed to the user: it should be stored in
the slots table in English but it should be defined as a translatable
string.

BP

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@21767 57a11ea4-9604-0410-9ed3-97b8803252fd
---
 src/gnome-utils/gnc-file.c | 77 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/src/gnome-utils/gnc-file.c b/src/gnome-utils/gnc-file.c
index 1d46f70d0d..2c3a474f6c 100644
--- a/src/gnome-utils/gnc-file.c
+++ b/src/gnome-utils/gnc-file.c
@@ -607,6 +607,77 @@ gnc_file_query_save (gboolean can_cancel)
     return TRUE;
 }
 
+
+
+static void features_test(const gchar *key, KvpValue *value, gpointer data)
+{
+  GList** unknown_features = (GList**) data;
+  char* feature_desc;
+
+  g_assert(data);
+
+  /* XXX: test if 'key' is an unknown feature. */
+
+  /* Yes, it is unknown, so add the description to the list: */
+  feature_desc = kvp_value_get_string(value);
+  g_assert(feature_desc);
+
+  *unknown_features = g_list_prepend(*unknown_features, feature_desc);  
+}
+
+/*
+ * Right now this is done by a KVP check for a features table.
+ * Currently we don't know about any features, so the mere
+ * existence of this KVP frame means we have a problem and
+ * need to tell the user.
+ *
+ * returns true if we found unknown features, false if we're okay.
+ */
+static gboolean test_unknown_features(QofSession* new_session)
+{
+    KvpFrame *frame = qof_book_get_slots (qof_session_get_book (new_session));
+    KvpValue *value;
+
+    g_assert(frame);
+    value = kvp_frame_get_value(frame, "features");
+
+    if (value)
+    {
+        GList* features_list = NULL;
+	frame = kvp_value_get_frame(value);
+	g_assert(frame);
+
+	/* Iterate over the members of this frame for unknown features */
+	kvp_frame_for_each_slot(frame, &features_test, &features_list);
+	if (features_list)
+	{
+            GList *i;
+            char* msg = g_strdup(
+                _("This Dataset contains features not supported by this "
+                  "version of GnuCash.  You must use a newer version of "
+                  "GnuCash in order to support the following features:"
+		  ));
+
+	    for (i = features_list; i; i=i->next)
+            {
+                char *tmp = g_strconcat(msg, "\n* ", _(i->data), NULL);
+                g_free (msg);
+                msg = tmp;
+            }
+
+	    // XXX: should pull out the file name here */
+	    gnc_error_dialog(gnc_ui_get_toplevel(), msg, "");
+	    
+	    g_free(msg);
+	    g_list_free(features_list);
+            return TRUE;
+	}
+    }
+
+    return FALSE;
+}
+
+
 /* private utilities for file open; done in two stages */
 
 #define RESPONSE_NEW  1
@@ -902,6 +973,12 @@ RESTART:
             uh_oh = show_session_error (ERR_BACKEND_MISC, newfile,
                                         GNC_FILE_DIALOG_OPEN);
         }
+
+	/* test for unknown features. */
+	if (!uh_oh)
+	{
+            uh_oh = test_unknown_features(new_session);
+        }
     }
 
     gnc_unset_busy_cursor (NULL);