Micro-optimize the roster refresh

The roster wrapper sucks and is way too slow. Halve refresh time by more
than 50% using manually managed counters.

src/core/handlers.py

@@ -867,7 +867,11 @@ def on_got_offline(self, presence):
     # If a resource got offline, display the message in the conversation with this
     # precise resource.
     contact = roster[jid.bare]
-    name = contact.name if contact and contact.name else jid.bare
+    name = jid.bare
+    if contact:
+        roster.connected -= 1
+        if contact.name:
+            name = contact.name
     if jid.resource:
         self.add_information_message_to_conversation_tab(jid.full, '\x195}%s is \x191}offline' % name)
     self.add_information_message_to_conversation_tab(jid.bare, '\x195}%s is \x191}offline' % name)
@@ -887,6 +891,7 @@ def on_got_online(self, presence):
     if contact is None:
         # Todo, handle presence coming from contacts not in roster
         return
+    roster.connected += 1
     roster.modified()
     if not logger.log_roster_change(jid.bare, 'got online'):
         self.information('Unable to write in the log file', 'Error')

src/roster.py

@@ -40,6 +40,8 @@ class Roster(object):
                                             section='var').split(':'))
         self.groups = {}
         self.contacts = {}
+        self.length = 0
+        self.connected = 0
 
         # Used for caching roster infos
         self.last_built = datetime.now()
@@ -104,11 +106,12 @@ class Roster(object):
         return self.__node.jid
 
     def get_and_set(self, jid):
-        if not jid in self.contacts:
+        contact = self.contacts.get(jid)
+        if contact is None:
             contact = Contact(self.__node[jid])
             self.contacts[jid] = contact
             return contact
-        return self.contacts[jid]
+        return contact
 
     def set_node(self, value):
         """Set the slixmpp RosterSingle for our roster"""
@@ -146,6 +149,7 @@ class Roster(object):
             contact = self.get_and_set(key)
             if key != self.jid and (contact and self.exists(contact)):
                 l.append(key)
+        self.length = len(l)
         return l
 
     def get_contacts(self):
@@ -190,11 +194,7 @@ class Roster(object):
         """
         Get the number of connected contacts
         """
-        n = 0
-        for contact in self:
-            if self.exists(contact) and len(contact):
-                n += 1
-        return n
+        return self.connected
 
     def update_contact_groups(self, contact):
         """Regenerate the RosterGroups when receiving a contact update"""
@@ -219,7 +219,7 @@ class Roster(object):
         (used to return the display size, but now we have
         the display cache in RosterWin for that)
         """
-        return len(self.jids())
+        return self.length
 
     def __repr__(self):
         ret = '== Roster:\nContacts:\n'
@@ -244,7 +244,6 @@ class Roster(object):
         except OSError:
             return
 
-
     def exists(self, contact):
         if not contact:
             return False