[glib] gtype: fix a no-op assertion

[Dan Winship <danw src gnome org>]

commit 34e1a537956e85d9d2db2127cd723a6c7456f793
Author: Dan Winship <danw gnome org>
Date:   Tue Aug 27 09:40:18 2013 -0400

    gtype: fix a no-op assertion
    
    g_type_class_add_private() was doing
    
        g_assert (node->data->instance.private_size <= 0xffff);
    
    but that field is a guint16, so the check was a no-op. (Noticed by
    clang, but not gcc for some reason.) Fix it to do the math in a gssize
    variable and do the bounds checking there before updating the struct
    field.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706888

 gobject/gtype.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/gobject/gtype.c b/gobject/gtype.c
index 1445691..5051639 100644
--- a/gobject/gtype.c
+++ b/gobject/gtype.c
@@ -4503,8 +4503,9 @@ g_type_class_add_private (gpointer g_class,
   
   G_WRITE_LOCK (&type_rw_lock);
 
-  node->data->instance.private_size = ALIGN_STRUCT (node->data->instance.private_size + private_size);
-  g_assert (node->data->instance.private_size <= 0xffff);
+  private_size = ALIGN_STRUCT (node->data->instance.private_size + private_size);
+  g_assert (private_size <= 0xffff);
+  node->data->instance.private_size = private_size;
   
   G_WRITE_UNLOCK (&type_rw_lock);
 }
@@ -4573,6 +4574,7 @@ g_type_class_adjust_private_offset (gpointer  g_class,
 {
   GType class_gtype = ((GTypeClass *) g_class)->g_type;
   TypeNode *node = lookup_type_node_I (class_gtype);
+  gssize private_size;
 
   g_return_if_fail (private_size_or_offset != NULL);
 
@@ -4606,8 +4608,9 @@ g_type_class_adjust_private_offset (gpointer  g_class,
 
   G_WRITE_LOCK (&type_rw_lock);
 
-  node->data->instance.private_size = ALIGN_STRUCT (node->data->instance.private_size + 
*private_size_or_offset);
-  g_assert (node->data->instance.private_size <= 0xffff);
+  private_size = ALIGN_STRUCT (node->data->instance.private_size + *private_size_or_offset);
+  g_assert (private_size <= 0xffff);
+  node->data->instance.private_size = private_size;
 
   *private_size_or_offset = -(gint) node->data->instance.private_size;