[dia] PyDia: fix wrong cast to Diagram* were DiagramData* (now really)

[Hans Breuer <hans src gnome org>]

commit 75b2085d50bb592a09cb632072679eb595194264
Author: Hans Breuer <hans breuer org>
Date:   Fri May 2 20:36:49 2014 +0200

    PyDia: fix wrong cast to Diagram* were DiagramData* (now really)
    
    PyDiaDiagramData_GetAttr() can deliver attributes from Diagram and
    DiagramData. In the stand alone or command line case these are not
    necessarily the same. E.g. file conversion is usually only done
    with DigramData.

 plug-ins/python/pydia-diagramdata.c |   24 ++++++++++++++----------
 1 files changed, 14 insertions(+), 10 deletions(-)
---
diff --git a/plug-ins/python/pydia-diagramdata.c b/plug-ins/python/pydia-diagramdata.c
index d95ca22..dfda2b9 100644
--- a/plug-ins/python/pydia-diagramdata.c
+++ b/plug-ins/python/pydia-diagramdata.c
@@ -342,7 +342,11 @@ static PyMemberDef PyDiaDiagramData_Members[] = {
 static PyObject *
 PyDiaDiagramData_GetAttr(PyDiaDiagramData *self, gchar *attr)
 {
-    Diagram *diagram = DIA_DIAGRAM_DATA(self->data);
+    DiagramData *data = DIA_DIAGRAM_DATA(self->data);
+    Diagram *diagram = NULL;
+
+    if (DIA_IS_DIAGRAM (self->data))
+       diagram = DIA_DIAGRAM(self->data);
 
     if (!strcmp(attr, "__members__"))
        return Py_BuildValue("[ssssssssssss]",
@@ -353,22 +357,22 @@ PyDiaDiagramData_GetAttr(PyDiaDiagramData *self, gchar *attr)
                            "layers", "active_layer",
                            "selected" );
     else if (!strcmp(attr, "extents"))
-      return PyDiaRectangle_New(&self->data->extents, NULL);
+      return PyDiaRectangle_New(&data->extents, NULL);
     else if (!strcmp(attr, "bg_color")) {
-      return PyDiaColor_New (&(self->data->bg_color));
+      return PyDiaColor_New (&(data->bg_color));
     }
     else if (!strcmp(attr, "layers")) {
-       guint i, len = self->data->layers->len;
+       guint i, len = data->layers->len;
        PyObject *ret = PyTuple_New(len);
 
        for (i = 0; i < len; i++)
            PyTuple_SetItem(ret, i, PyDiaLayer_New(
-                       g_ptr_array_index(self->data->layers, i)));
+                       g_ptr_array_index(data->layers, i)));
        return ret;
     } else if (!strcmp(attr, "active_layer")) {
-       return PyDiaLayer_New(self->data->active_layer);
+       return PyDiaLayer_New(data->active_layer);
     } else if (!strcmp(attr, "paper")) {
-        return PyDiaPaperinfo_New (&self->data->paper);
+        return PyDiaPaperinfo_New (&data->paper);
     }
     else if (diagram && !strcmp(attr, "grid_width")) 
       return Py_BuildValue("(dd)", diagram->grid.width_x, diagram->grid.width_y);
@@ -391,7 +395,7 @@ PyDiaDiagramData_GetAttr(PyDiaDiagramData *self, gchar *attr)
       return ret;
     }
     else if (!strcmp(attr, "layers")) {
-       guint i, len = self->data->layers->len;
+       guint i, len = data->layers->len;
        PyObject *ret = PyTuple_New(len);
 
        for (i = 0; i < len; i++)
@@ -400,7 +404,7 @@ PyDiaDiagramData_GetAttr(PyDiaDiagramData *self, gchar *attr)
        return ret;
     }
     else if (!strcmp(attr, "active_layer")) {
-      return PyDiaLayer_New(self->data->active_layer);
+      return PyDiaLayer_New(data->active_layer);
     }
     else if (!strcmp(attr, "selected")) {
        PyObject *ret;
@@ -408,7 +412,7 @@ PyDiaDiagramData_GetAttr(PyDiaDiagramData *self, gchar *attr)
        gint i;
 
        ret = PyTuple_New(g_list_length(self->data->selected));
-       for (i = 0, tmp = self->data->selected; tmp; i++, tmp = tmp->next)
+       for (i = 0, tmp = data->selected; tmp; i++, tmp = tmp->next)
            PyTuple_SetItem(ret, i, PyDiaObject_New((DiaObject *)tmp->data));
        return ret;
     }