[dia] Bug 488269 - empty undo actions when no properties are changed

[Hans Breuer <hans src gnome org>]

commit 081fa89e1aa7080ffbe11ba000a83bdf1a6aa452
Author: Hans Breuer <hans breuer org>
Date:   Sun Jun 12 15:37:17 2011 +0200

    Bug 488269 - empty undo actions when no properties are changed
    
    This is not a complete fix, but some related behavior change.
    The dict property was claiming a change even when not touched,
    that's corrected now. But creating an empty change is necessary
    to fulfill the contract of DiaObject::apply_props_from_dialog().
    
    We could implement some silent ignoring of these empty changes,
    but IMO it would be better to not enable the Apply/Ok at all,
    if there is nothing to change.

 lib/prop_dict.c  |   13 +++++++++----
 lib/propobject.c |    4 +++-
 2 files changed, 12 insertions(+), 5 deletions(-)
---
diff --git a/lib/prop_dict.c b/lib/prop_dict.c
index c739ae7..a03f393 100644
--- a/lib/prop_dict.c
+++ b/lib/prop_dict.c
@@ -211,7 +211,7 @@ edited (GtkCellRendererText *cell,
 
   gtk_tree_model_get_iter (model, &iter, path);
   gtk_tree_store_set (GTK_TREE_STORE (model), &iter, VALUE_COLUMN, new_text, -1);
-
+  g_object_set_data (G_OBJECT (model), "modified", GINT_TO_POINTER (1));
   gtk_tree_path_free (path);
 }
 
@@ -259,7 +259,9 @@ dictprop_get_widget (DictProperty *prop, PropDialog *dialog)
   GtkWidget *ret;
   ret = _create_view (_create_model (prop));
   gtk_widget_show_all (ret);
-  /* FIXME: prophandler_connect(&prop->common, G_OBJECT(ret), "value_changed"); */
+  /* prophandler_connect(&prop->common, G_OBJECT(ret), "value_changed");
+   * It's not so easy, we are maintaining our own changed state via edited signal
+   */
   return ret;
 }
 static void 
@@ -277,6 +279,8 @@ dictprop_reset_widget(DictProperty *prop, GtkWidget *widget)
     prop->dict = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
   g_hash_table_foreach (prop->dict, _keyvalue_fill_model, model);
 
+  g_object_set_data (G_OBJECT (model), "modified", GINT_TO_POINTER (0));
+
   /* also add the well known ? */
   for (wkk = _well_known; wkk->name != NULL; ++wkk) {
     gchar *val;
@@ -316,8 +320,9 @@ dictprop_set_from_widget(DictProperty *prop, GtkWidget *widget)
           g_hash_table_insert (prop->dict, key, val);
 	else /* delete stuff which has no value any longer */
 	  g_hash_table_remove (prop->dict, key);
-	/* FIXME: enough to replace prophandler_connect() ? */
-	prop->common.experience &= ~PXP_NOTSET;
+	/* enough to replace prophandler_connect() ? */
+	if (g_object_get_data (G_OBJECT (model), "modified"))
+	  prop->common.experience &= ~PXP_NOTSET;
       }
     } while (gtk_tree_model_iter_next (model, &iter));
   }
diff --git a/lib/propobject.c b/lib/propobject.c
index 2f9d268..026b35a 100644
--- a/lib/propobject.c
+++ b/lib/propobject.c
@@ -217,7 +217,9 @@ object_apply_props_from_dialog(DiaObject *obj, WIDGET *dialog_widget)
     if ((p->experience & PXP_NOTSET) == 0)
       g_ptr_array_add(props, p);
   }
-
+  /* with an empty list there is no change at all but simply
+   * returning NULL is against the contract ...
+   */
   if (!obj->ops->apply_properties_list) {
     g_warning("using a fallback function to apply properties;"
               " undo may not work correctly");