hostkeymap: Globally cache the host lookup

Rather than make the callers worry about it

virtinst/VirtualGraphics.py

@@ -125,10 +125,6 @@ class VirtualGraphics(VirtualDevice):
         if channels:
             self.channels = channels
 
-    def _cache(self):
-        # Make sure we've cached the _local_keymap value before copy()
-        self._default_keymap()
-
     def _default_keymap(self, force_local=False):
         if (not force_local and
             self.conn.check_conn_support(

virtinst/hostkeymap.py

@@ -20,6 +20,9 @@
 import logging
 import re
 
+
+_cached_keymap = None
+
 # Host keytable entry : keymap name in qemu/xen
 # Only use lower case entries: all lookups are .lower()'d
 keytable = {
@@ -130,6 +133,13 @@ def _xorg_keymap():
 
 
 def default_keymap():
+    global _cached_keymap
+    if _cached_keymap is None:
+        _cached_keymap = _default_keymap()
+    return _cached_keymap
+
+
+def _default_keymap():
     """
     Look in various config files for the host machine's keymap, and attempt
     to map it to a keymap supported by qemu
@@ -168,13 +178,10 @@ def default_keymap():
         return default
 
     kt = kt.lower()
-
     keymap = sanitize_keymap(kt)
-
     if not keymap:
         logging.debug("Didn't match keymap '%s' in keytable!", kt)
         return default
-
     return keymap
 
 

virtinst/xmlbuilder.py

@@ -519,17 +519,7 @@ class XMLBuilder(object):
             self._parsexml(parsexml, parsexmlnode)
 
 
-    def _cache(self):
-        """
-        This is a hook for classes to cache any state that is expensive
-        to lookup before we copy the object as part of Guest.get_xml_config.
-        Saves us from possibly doing the lookup over and over
-        """
-        pass
-
-
     def copy(self):
-        self._cache()
         return copy.copy(self)
 
     def _get_conn(self):