Handle the roster order cache as a real cache

When an external (or internal) event may cause the order of the
cache to be modified, or new elements to be added, schedule it
for a rebuild. Otherwise, don’t, and only rebuild it when
refreshing (that should improve refresh speed a lot).

Also, if the position in the roster is further than the total size
of the roster, go back to the top instead of displaying an empty
window with “+++”.

3 files changed, 61 insertions, 22 deletions

diff --git a/src/core.py b/src/core.py
index 1d946df3..4c1566bd 100644
--- a/src/core.py
+++ b/src/core.py
@@ -152,6 +152,7 @@ class Core(object):
         self.plugin_manager = PluginManager(self)
         self.events = events.EventHandler()
 
+
         # global commands, available from all tabs
         # a command is tuple of the form:
         # (the function executing the command. Takes a string as argument,
@@ -298,6 +299,8 @@ class Core(object):
         log.debug("Reloading the config…")
         config.__init__(config.file_name)
         log.debug("Config reloaded.")
+        # in case some roster options have changed
+        roster.modified()
 
     def exit_from_signal(self, *args, **kwargs):
         """
@@ -2060,6 +2063,8 @@ class Core(object):
         elif option == 'plugins_conf_dir':
             path = os.path.expanduser(value)
             self.plugin_manager.on_plugins_conf_dir_change(path)
+        # in case some roster options have changed
+        roster.modified()
         self.call_for_resize()
         self.information(*info)
 
@@ -2791,6 +2796,7 @@ class Core(object):
         contact = roster[message['from'].bare]
         if not contact:
             return
+        roster.modified()
         item = message['pubsub_event']['items']['item']
         old_mood = contact.mood
         if item.xml.find('{http://jabber.org/protocol/mood}mood'):
@@ -2820,6 +2826,7 @@ class Core(object):
         contact = roster[message['from'].bare]
         if not contact:
             return
+        roster.modified()
         item = message['pubsub_event']['items']['item']
         old_activity = contact.activity
         if item.xml.find('{http://jabber.org/protocol/activity}activity'):
@@ -2855,6 +2862,7 @@ class Core(object):
         contact = roster[message['from'].bare]
         if not contact:
             return
+        roster.modified()
         item = message['pubsub_event']['items']['item']
         old_tune = contact.tune
         if item.xml.find('{http://jabber.org/protocol/tune}tune'):
@@ -3085,6 +3093,7 @@ class Core(object):
             contact.pending_in = True
             self.information('%s wants to subscribe to your presence' % jid, 'Roster')
             self.get_tab_by_number(0).state = 'highlight'
+            roster.modified()
         if isinstance(self.current_tab(), tabs.RosterInfoTab):
             self.refresh_window()
 
@@ -3096,6 +3105,9 @@ class Core(object):
             self.information('%s accepted your contact proposal' % jid, 'Roster')
         if contact.pending_out:
             contact.pending_out = False
+
+        roster.modified()
+
         if isinstance(self.current_tab(), tabs.RosterInfoTab):
             self.refresh_window()
 
@@ -3105,6 +3117,7 @@ class Core(object):
         contact = roster[jid]
         if not contact:
             return
+        roster.modified()
         self.information('%s does not want to receive your status anymore.' % jid, 'Roster')
         self.get_tab_by_number(0).state = 'highlight'
         if isinstance(self.current_tab(), tabs.RosterInfoTab):
@@ -3116,6 +3129,7 @@ class Core(object):
         contact = roster[jid]
         if not contact:
             return
+        roster.modified()
         if contact.pending_out:
             self.information('%s rejected your contact proposal' % jid, 'Roster')
             contact.pending_out = False
@@ -3137,6 +3151,7 @@ class Core(object):
             tab.unlock()
         if contact is None:
             return
+        roster.modified()
         contact.error = None
         self.events.trigger('normal_presence', presence, contact[jid.full])
         tab = self.get_conversation_by_jid(jid, create=False)
@@ -3151,6 +3166,7 @@ class Core(object):
         contact = roster[jid.bare]
         if not contact:
             return
+        roster.modified()
         contact.error = presence['error']['type'] + ': ' + presence['error']['condition']
 
     def on_got_offline(self, presence):
@@ -3168,6 +3184,7 @@ class Core(object):
             self.add_information_message_to_conversation_tab(jid.full, '\x195}%s is \x191}offline' % (jid.full))
         self.add_information_message_to_conversation_tab(jid.bare, '\x195}%s is \x191}offline' % (jid.bare))
         self.information('\x193}%s \x195}is \x191}offline' % (jid.bare), 'Roster')
+        roster.modified()
         if isinstance(self.current_tab(), tabs.RosterInfoTab):
             self.refresh_window()
 
@@ -3182,6 +3199,7 @@ class Core(object):
         if contact is None:
             # Todo, handle presence coming from contacts not in roster
             return
+        roster.modified()
         if not logger.log_roster_change(jid.bare, 'got online'):
             self.information(_('Unable to write in the log file'), 'Error')
         resource = Resource(jid.full, {
diff --git a/src/roster.py b/src/roster.py
index b0f3cf65..5ddbdbb2 100644
--- a/src/roster.py
+++ b/src/roster.py
@@ -17,6 +17,7 @@ from contact import Contact
 from roster_sorting import SORTING_METHODS, GROUP_SORTING_METHODS
 
 from os import path as p
+from datetime import datetime
 from common import safeJID
 from sleekxmpp import JID
 from sleekxmpp.exceptions import IqError, IqTimeout
@@ -43,6 +44,17 @@ class Roster(object):
         self.groups = {}
         self.contacts = {}
 
+        # Used for caching roster infos
+        self.last_built = datetime.now()
+        self.last_modified = datetime.now()
+
+    def modified(self):
+        self.last_modified = datetime.now()
+
+    @property
+    def needs_rebuild(self):
+        return self.last_modified >= self.last_built
+
     def __getitem__(self, key):
         """Get a Contact from his bare JID"""
         key = safeJID(key).bare
diff --git a/src/windows.py b/src/windows.py
index 49e76ff5..0040ee0c 100644
--- a/src/windows.py
+++ b/src/windows.py
@@ -1830,34 +1830,43 @@ class RosterWin(Win):
             self.start_pos = 1
         return self.start_pos != pos
 
+    def build_roster_cache(self, roster):
+        """
+        Regenerates the roster cache if needed
+        """
+        with g_lock:
+            if roster.needs_rebuild:
+                log.debug('The roster has changed, rebuilding the cache…')
+                show_offline = config.get('roster_show_offline', 'false') == 'true'
+                sort = config.get('roster_sort', 'jid:show') or 'jid:show'
+                group_sort = config.get('roster_group_sort', 'name') or 'name'
+                self.roster_cache = []
+                # build the cache
+                for group in roster.get_groups(group_sort):
+                    contacts_filtered = group.get_contacts(roster.contact_filter)
+                    if (not show_offline and group.get_nb_connected_contacts() == 0) or not contacts_filtered:
+                        continue    # Ignore empty groups
+                    self.roster_cache.append(group)
+                    if group.folded:
+                        continue # ignore folded groups
+                    for contact in group.get_contacts(roster.contact_filter, sort):
+                        if not show_offline and len(contact) == 0:
+                            continue # ignore offline contacts
+                        self.roster_cache.append(contact)
+                        if not contact.folded(group.name):
+                            for resource in contact.get_resources():
+                                self.roster_cache.append(resource)
+
     def refresh(self, roster):
         """
-        We get the roster object
+        We display a number of lines from the roster cache
+        (and rebuild it if needed)
         """
         log.debug('Refresh: %s',self.__class__.__name__)
-        self.roster_cache = []
-        show_offline = config.get('roster_show_offline', 'false') == 'true'
-        sort = config.get('roster_sort', 'jid:show') or 'jid:show'
-        group_sort = config.get('roster_group_sort', 'name') or 'name'
-        # build the cache
-        for group in roster.get_groups(group_sort):
-            contacts_filtered = group.get_contacts(roster.contact_filter)
-            if (not show_offline and group.get_nb_connected_contacts() == 0) or not contacts_filtered:
-                continue    # Ignore empty groups
-            self.roster_cache.append(group)
-            if group.folded:
-                continue # ignore folded groups
-            for contact in group.get_contacts(roster.contact_filter, sort):
-                if not show_offline and len(contact) == 0:
-                    continue # ignore offline contacts
-                self.roster_cache.append(contact)
-                if not contact.folded(group.name):
-                    for resource in contact.get_resources():
-                        self.roster_cache.append(resource)
-
+        self.build_roster_cache(roster)
         with g_lock:
             self.roster_len = len(roster);
-            self.move_cursor_up(self.roster_len - self.pos if self.pos >= self.roster_len else 0)
+            self.move_cursor_up(self.roster_len + self.pos if self.pos >= self.roster_len else 0)
             self._win.erase()
             self._win.move(0, 0)
             self.draw_roster_information(roster)