Performance improvement on FLAGS-only FETCH

* Compute the intersection set of the uids on a FETCH, so we avoid
  iterating through the non-existant UIDs.
* Dispatch FLAGS query to our specialized method, that fetches all the
  flags documents and return objects that only specify one subset of the
  MessagePart interface, apt to render flags quickly with less queries
  overhead.
* Overwrite the do_FETCH command in the imap Server to use fetch_flags.
* Use deferLater for a better dispatch of tasks in the reactor.

1 files changed, 35 insertions, 2 deletions

diff --git a/src/leap/mail/imap/service/imap.py b/src/leap/mail/imap/service/imap.py
index c48e5c5..e877869 100644
--- a/src/leap/mail/imap/service/imap.py
+++ b/src/leap/mail/imap/service/imap.py
@@ -22,6 +22,7 @@ from copy import copy
 import logging
 
 from twisted.internet.protocol import ServerFactory
+from twisted.internet.defer import maybeDeferred
 from twisted.internet.error import CannotListenError
 from twisted.mail import imap4
 from twisted.python import log
@@ -78,7 +79,6 @@ class LeapIMAPServer(imap4.IMAP4Server):
         :param line: the line from the server, without the line delimiter.
         :type line: str
         """
-        print "RECV: STATE (%s)" % self.state
         if self.theAccount.closed is True and self.state != "unauth":
             log.msg("Closing the session. State: unauth")
             self.state = "unauth"
@@ -89,7 +89,7 @@ class LeapIMAPServer(imap4.IMAP4Server):
             msg = line[:7] + " [...]"
         else:
             msg = copy(line)
-        log.msg('rcv: %s' % msg)
+        log.msg('rcv (%s): %s' % (self.state, msg))
         imap4.IMAP4Server.lineReceived(self, line)
 
     def authenticateLogin(self, username, password):
@@ -111,6 +111,39 @@ class LeapIMAPServer(imap4.IMAP4Server):
         leap_events.signal(IMAP_CLIENT_LOGIN, "1")
         return imap4.IAccount, self.theAccount, lambda: None
 
+    def do_FETCH(self, tag, messages, query, uid=0):
+        """
+        Overwritten fetch dispatcher to use the fast fetch_flags
+        method
+        """
+        log.msg("LEAP Overwritten fetch...")
+        if not query:
+            self.sendPositiveResponse(tag, 'FETCH complete')
+            return  # XXX ???
+
+        cbFetch = self._IMAP4Server__cbFetch
+        ebFetch = self._IMAP4Server__ebFetch
+
+        if str(query[0]) == "flags":
+            self._oldTimeout = self.setTimeout(None)
+            # no need to call iter, we get a generator
+            maybeDeferred(
+                self.mbox.fetch_flags, messages, uid=uid
+            ).addCallback(
+                cbFetch, tag, query, uid
+            ).addErrback(ebFetch, tag)
+        else:
+            self._oldTimeout = self.setTimeout(None)
+            # no need to call iter, we get a generator
+            maybeDeferred(
+                self.mbox.fetch, messages, uid=uid
+            ).addCallback(
+                cbFetch, tag, query, uid
+            ).addErrback(ebFetch, tag)
+
+    select_FETCH = (do_FETCH, imap4.IMAP4Server.arg_seqset,
+                    imap4.IMAP4Server.arg_fetchatt)
+
 
 class IMAPAuthRealm(object):
     """