[template-glib] iter: fix iteration of GListModel instances

[Christian Hergert <chergert src gnome org>]

commit 4bb566945aa3f888abb244f50dec184ca230a733
Author: Christian Hergert <chergert redhat com>
Date:   Sat Aug 6 15:39:50 2016 -0700

    iter: fix iteration of GListModel instances
    
    This fixes support for iterating list models like:
    
      {{for item in foo.items}}
        {{item.foo}}
      {{end}}

 src/tmpl-iterator.c |   27 ++++++++++++++++++++-------
 1 files changed, 20 insertions(+), 7 deletions(-)
---
diff --git a/src/tmpl-iterator.c b/src/tmpl-iterator.c
index 1446d68..4c1c897 100644
--- a/src/tmpl-iterator.c
+++ b/src/tmpl-iterator.c
@@ -63,7 +63,10 @@ list_model_move_next (TmplIterator *iter)
   guint index = GPOINTER_TO_INT (iter->data1);
   guint n_items = GPOINTER_TO_INT (iter->data2);
 
-  if (++index < n_items)
+  index++;
+
+  /* We are 1 based indexing here */
+  if (index <= n_items)
     {
       iter->data1 = GINT_TO_POINTER (index);
       return TRUE;
@@ -79,14 +82,14 @@ list_model_get_value (TmplIterator *iter,
   guint index = GPOINTER_TO_INT (iter->data1);
   GObject *obj;
 
-  obj = g_list_model_get_item (iter->instance, index);
+  g_return_val_if_fail (index > 0, FALSE);
 
-  if (obj != NULL)
-    g_value_init (value, G_OBJECT_TYPE (obj));
-  else
-    g_value_init (value, G_TYPE_OBJECT);
+  obj = g_list_model_get_item (iter->instance, index - 1);
 
-  g_value_take_object (value, obj);
+  g_value_init (value, g_list_model_get_item_type (iter->instance));
+
+  if (obj != NULL)
+    g_value_take_object (value, obj);
 
   return TRUE;
 }
@@ -113,7 +116,17 @@ tmpl_iterator_init (TmplIterator *iter,
       iter->move_next = list_model_move_next;
       iter->get_value = list_model_get_value;
       iter->destroy = NULL;
+
+      if (iter->instance != NULL)
+        {
+          guint n_items;
+
+          n_items = g_list_model_get_n_items (iter->instance);
+          iter->data1 = GUINT_TO_POINTER (iter->data1);
+          iter->data2 = GUINT_TO_POINTER (n_items);
+        }
     }
+
   /* TODO: More iter types */
 }