[orca] Add more sanity checks for defunct objects

[Joanmarie Diggs <joanied src gnome org>]

commit 18b15ff4d7a12d25fa667bb52dd82feeb6850dd4
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Nov 30 15:29:36 2015 -0500

    Add more sanity checks for defunct objects

 src/orca/script_utilities.py |   36 +++++++++++++++++++++++++++++++++---
 1 files changed, 33 insertions(+), 3 deletions(-)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index 0249771..fb0b2a5 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -976,7 +976,17 @@ class Utilities:
         return self.getContainingDocument(obj) is None
 
     def isSpreadSheetTable(self, obj):
-        if not (obj and obj.getRole() == pyatspi.ROLE_TABLE):
+        if not obj:
+            return False
+
+        try:
+            role = obj.getRole()
+        except:
+            msg = 'ERROR: Exception getting role of %s' % obj
+            debug.println(debug.LEVEL_INFO, msg, True)
+            return False
+
+        if not role == pyatspi.ROLE_TABLE:
             return False
 
         doc = self.getContainingDocument(obj)
@@ -1000,19 +1010,39 @@ class Utilities:
         return False
 
     def isTextDocumentCell(self, obj):
+        if not obj:
+            return False
+
+        try:
+            role = obj.getRole()
+        except:
+            msg = 'ERROR: Exception getting role of %s' % obj
+            debug.println(debug.LEVEL_INFO, msg, True)
+            return False
+
         cellRoles = [pyatspi.ROLE_TABLE_CELL,
                      pyatspi.ROLE_COLUMN_HEADER,
                      pyatspi.ROLE_ROW_HEADER]
-        if not (obj and obj.getRole() in cellRoles):
+        if not role in cellRoles:
             return False
 
         return pyatspi.findAncestor(obj, self.isTextDocumentTable)
 
     def isSpreadSheetCell(self, obj):
+        if not obj:
+            return False
+
+        try:
+            role = obj.getRole()
+        except:
+            msg = 'ERROR: Exception getting role of %s' % obj
+            debug.println(debug.LEVEL_INFO, msg, True)
+            return False
+
         cellRoles = [pyatspi.ROLE_TABLE_CELL,
                      pyatspi.ROLE_COLUMN_HEADER,
                      pyatspi.ROLE_ROW_HEADER]
-        if not (obj and obj.getRole() in cellRoles):
+        if not role in cellRoles:
             return False
 
         return pyatspi.findAncestor(obj, self.isSpreadSheetTable)