[kupfer] keybindings: Refuse binding Return, space and BackSpace

[Ulrik Sverdrup <usverdrup src gnome org>]

commit 3ad5dbb2499648188bc954f72f9c8681ed81e894
Author: Ulrik Sverdrup <ulrik sverdrup gmail com>
Date:   Tue Apr 6 16:36:41 2010 +0200

    keybindings: Refuse binding Return, space and BackSpace
    
    make sure the user can't bind some keys that it would be very
    confusing to bind. This only affects binding the keys without
    modifiers.

 kupfer/ui/keybindings.py |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/kupfer/ui/keybindings.py b/kupfer/ui/keybindings.py
index c96b549..a4c6908 100644
--- a/kupfer/ui/keybindings.py
+++ b/kupfer/ui/keybindings.py
@@ -1,6 +1,7 @@
 import gobject
 
 from kupfer import pretty
+from kupfer import kupferstring
 
 KEYBINDING_DEFAULT = 1
 KEYBINDING_MAGIC = 2
@@ -65,7 +66,7 @@ def bind_key(keystr, keybinding_target=KEYBINDING_DEFAULT):
 
 	keybinding_target = int(keybinding_target)
 	callback = lambda : GetKeyboundObject()._keybinding(keybinding_target)
-	if keystr and len(keystr) == 1:
+	if not _is_sane_keybinding(keystr):
 		pretty.print_error(__name__, "Refusing to bind key", repr(keystr))
 		return False
 
@@ -85,3 +86,13 @@ def bind_key(keystr, keybinding_target=KEYBINDING_DEFAULT):
 		_register_bound_key(keystr, keybinding_target)
 	return succ
 
+
+def _is_sane_keybinding(keystr):
+	"Refuse keys that we absolutely do not want to bind"
+	if keystr is None:
+		return True
+	if len(keystr) == 1 and keystr.isalnum():
+		return False
+	if keystr in set(["Return", "space", "BackSpace", "Escape"]):
+		return False
+	return True