[at-spi2-atk] Don't try to unref an object if atk returned NULL

[Mike Gorse <mgorse src gnome org>]

commit b127ebb72cce5c710445b1c823379256921f1e45
Author: Mike Gorse <mgorse novell com>
Date:   Sun Jan 29 19:03:13 2012 -0600

    Don't try to unref an object if atk returned NULL

 atk-adaptor/adaptors/component-adaptor.c |    3 ++-
 atk-adaptor/adaptors/selection-adaptor.c |    3 ++-
 atk-adaptor/adaptors/table-adaptor.c     |   13 ++++++++-----
 3 files changed, 12 insertions(+), 7 deletions(-)
---
diff --git a/atk-adaptor/adaptors/component-adaptor.c b/atk-adaptor/adaptors/component-adaptor.c
index f477348..d74c764 100644
--- a/atk-adaptor/adaptors/component-adaptor.c
+++ b/atk-adaptor/adaptors/component-adaptor.c
@@ -86,7 +86,8 @@ impl_GetAccessibleAtPoint (DBusConnection * bus, DBusMessage * message,
     atk_component_ref_accessible_at_point (component, x, y,
                                            (AtkCoordType) coord_type);
   reply = spi_object_return_reference (message, child);
-  g_object_unref (child);
+  if (child)
+    g_object_unref (child);
 
   return reply;
 }
diff --git a/atk-adaptor/adaptors/selection-adaptor.c b/atk-adaptor/adaptors/selection-adaptor.c
index 23b0a4f..b39b22d 100644
--- a/atk-adaptor/adaptors/selection-adaptor.c
+++ b/atk-adaptor/adaptors/selection-adaptor.c
@@ -69,7 +69,8 @@ impl_GetSelectedChild (DBusConnection * bus, DBusMessage * message,
     }
   atk_object = atk_selection_ref_selection (selection, selectedChildIndex);
   reply = spi_object_return_reference (message, atk_object);
-  g_object_unref (atk_object);
+  if (atk_object)
+    g_object_unref (atk_object);
 
   return reply;
 }
diff --git a/atk-adaptor/adaptors/table-adaptor.c b/atk-adaptor/adaptors/table-adaptor.c
index 26fec2b..8c334b6 100644
--- a/atk-adaptor/adaptors/table-adaptor.c
+++ b/atk-adaptor/adaptors/table-adaptor.c
@@ -110,7 +110,8 @@ impl_GetAccessibleAt (DBusConnection * bus, DBusMessage * message,
     }
   obj = atk_table_ref_at (table, row, column);
   reply = spi_object_return_reference (message, obj);
-  g_object_unref (obj);
+  if (obj)
+    g_object_unref (obj);
 
   return reply;
 }
@@ -629,9 +630,8 @@ impl_GetRowColumnExtentsAtIndex (DBusConnection * bus, DBusMessage * message,
   dbus_bool_t is_selected;
   dbus_bool_t ret;
   DBusMessage *reply;
-
   AtkObject *cell;
-  AtkRole role;
+  AtkRole role = ATK_ROLE_INVALID;
 
   g_return_val_if_fail (ATK_IS_TABLE (user_data),
                         droute_not_yet_handled_error (message));
@@ -647,8 +647,11 @@ impl_GetRowColumnExtentsAtIndex (DBusConnection * bus, DBusMessage * message,
   col_extents = atk_table_get_column_extent_at (table, row, column);
   is_selected = atk_table_is_selected (table, row, column);
   cell = atk_table_ref_at (table, row, column);
-  role = atk_object_get_role (cell);
-  g_object_unref (cell);
+  if (cell)
+  {
+    role = atk_object_get_role (cell);
+    g_object_unref (cell);
+  }
   ret = (role == ATK_ROLE_TABLE_CELL ? TRUE : FALSE);
   reply = dbus_message_new_method_return (message);
   if (reply)