Add support for roster versioning.

This was XEP-0237, but is now part of RFC 6121.

Roster backends should now expose two additional methods:

version(jid):
    Return the version of the given JID's roster.
set_version(jid, version):
    Update the version of the given JID's roster.

A new state field will be passed to the backend if an item
has been marked for removal. This is 'removed' which will
be set to True.

1 files changed, 28 insertions, 0 deletions

diff --git a/sleekxmpp/roster/single.py b/sleekxmpp/roster/single.py
index 159eb07d..518afebe 100644
--- a/sleekxmpp/roster/single.py
+++ b/sleekxmpp/roster/single.py
@@ -57,11 +57,28 @@ class RosterNode(object):
         self.auto_authorize = True
         self.auto_subscribe = True
         self.last_status = None
+        self._version = ''
         self._jids = {}
 
         if self.db:
+            if hasattr(self.db, 'version'):
+                self._version = self.db.version(self.jid)
             for jid in self.db.entries(self.jid):
                 self.add(jid)
+    
+    @property
+    def version(self):
+        """Retrieve the roster's version ID."""
+        if self.db and hasattr(self.db, 'version'):
+            self._version = self.db.version(self.jid)
+        return self._version
+
+    @version.setter
+    def version(self, version):
+        """Set the roster's version ID."""
+        self._version = version
+        if self.db and hasattr(self.db, 'set_version'):
+            self.db.set_version(self.jid, version)
 
     def __getitem__(self, key):
         """
@@ -75,6 +92,17 @@ class RosterNode(object):
             self.add(key, save=True)
         return self._jids[key]
 
+    def __delitem__(self, key):
+        """
+        Remove a roster item from the local storage.
+
+        To remove an item from the server, use the remove() method.
+        """
+        if isinstance(key, JID):
+            key = key.bare
+        if key in self._jids:
+            del self._jids[key]
+
     def __len__(self):
         """Return the number of JIDs referenced by the roster."""
         return len(self._jids)