reconnect XMPP when NetWatcher notices a change

Assistant/Pushes.hs

@@ -11,6 +11,7 @@ import Common.Annex
 import Utility.TSet
 
 import Control.Concurrent.STM
+import Control.Concurrent.MSampleVar
 import Data.Time.Clock
 import qualified Data.Map as M
 
@@ -18,8 +19,13 @@ import qualified Data.Map as M
 type PushMap = M.Map Remote UTCTime
 type FailedPushMap = TMVar PushMap
 
-{- Used to notify about successful pushes. -}
-newtype PushNotifier = PushNotifier (TSet UUID)
+{- The TSet is recent, successful pushes that other remotes should be
+ - notified about.
+ -
+ - The MSampleVar is written to when the PushNotifier thread should be
+ - restarted for some reason.
+ -}
+data PushNotifier = PushNotifier (TSet UUID) (MSampleVar ())
 
 {- The TMVar starts empty, and is left empty when there are no
  - failed pushes. This way we can block until there are some failed pushes.
@@ -50,10 +56,18 @@ changeFailedPushMap v a = atomically $
 			| otherwise = putTMVar v $! m
 
 newPushNotifier :: IO PushNotifier
-newPushNotifier = PushNotifier <$> newTSet
+newPushNotifier = PushNotifier
+	<$> newTSet
+	<*> newEmptySV
 
 notifyPush :: [UUID] -> PushNotifier -> IO ()
-notifyPush us (PushNotifier s) = putTSet s us
+notifyPush us (PushNotifier s _) = putTSet s us
 
 waitPush :: PushNotifier -> IO [UUID]
-waitPush (PushNotifier s) = getTSet s
+waitPush (PushNotifier s _) = getTSet s
+
+notifyRestart :: PushNotifier -> IO ()
+notifyRestart (PushNotifier _ sv) = writeSV sv ()
+
+waitRestart :: PushNotifier -> IO ()
+waitRestart (PushNotifier _ sv) = readSV sv

Assistant/Threads/NetWatcher.hs

@@ -70,6 +70,7 @@ dbusThread st dstatus scanremotes pushnotifier =
 			)
 		handleconn = do
 			debug thisThread ["detected network connection"]
+			notifyRestart pushnotifier
 			handleConnection st dstatus scanremotes pushnotifier
 		onerr e _ = do
 			runThreadState st $

Assistant/Threads/PushNotifier.hs

@@ -28,11 +28,18 @@ import Data.Time.Clock
 thisThread :: ThreadName
 thisThread = "PushNotifier"
 
+controllerThread :: PushNotifier -> IO () -> IO ()
+controllerThread pushnotifier a = forever $ do
+	tid <- forkIO a
+	waitRestart pushnotifier
+	killThread tid
+
 pushNotifierThread :: ThreadState -> DaemonStatusHandle -> PushNotifier -> NamedThread
-pushNotifierThread st dstatus pushnotifier = NamedThread thisThread $ do
+pushNotifierThread st dstatus pushnotifier = NamedThread thisThread $
+	controllerThread pushnotifier $ do
 		v <- runThreadState st $ getXMPPCreds
 		case v of
-		Nothing -> return () -- no creds? exit thread
+			Nothing -> noop
 			Just c -> loop c =<< getCurrentTime
 	where
 		loop c starttime = do
@@ -53,7 +60,6 @@ pushNotifierThread st dstatus pushnotifier = NamedThread thisThread $ do
 					threadDelaySeconds (Seconds 300)
 					loop c =<< getCurrentTime
 
-		
 		sendnotifications = forever $ do
 			us <- liftIO $ waitPush pushnotifier
 			let payload = [extendedAway, encodePushNotification us]

Assistant/XMPP.hs

@@ -16,7 +16,7 @@ import Network
 import Control.Concurrent
 import qualified Data.Text as T
 import Data.XML.Types
-import Control.Exception as E
+import Control.Exception (SomeException)
 
 {- Everything we need to know to connect to an XMPP server. -}
 data XMPPCreds = XMPPCreds
@@ -53,7 +53,11 @@ connectXMPP' jid c a = go =<< lookupSRV srvrecord
 				a jid
 			ifM (isEmptyMVar mv) (go rest, return r)
 
-		run h p a' = E.try (runClientError (Server serverjid h p) jid (xmppUsername c) (xmppPassword c) (void a')) :: IO (Either SomeException ())
+		{- Async exceptions are let through so the XMPP thread can
+		 - be killed. -}
+		run h p a' = tryNonAsync $
+			runClientError (Server serverjid h p) jid
+				(xmppUsername c) (xmppPassword c) (void a')
 
 {- XMPP runClient, that throws errors rather than returning an Either -}
 runClientError :: Server -> JID -> T.Text -> T.Text -> XMPP a -> IO a

Utility/DBus.hs

@@ -9,6 +9,8 @@
 
 module Utility.DBus where
 
+import Utility.Exception
+
 import DBus.Client
 import DBus
 import Data.Maybe
@@ -70,10 +72,7 @@ persistentClient :: IO (Maybe Address) -> v -> (SomeException -> v -> IO v) -> (
 persistentClient getaddr v onretry clientaction =
 	{- runClient can fail with not just ClientError, but also other
 	 - things, if dbus is not running. Let async exceptions through. -}
-	runClient getaddr clientaction `E.catches`
-		[ Handler (\ (e :: AsyncException) -> E.throw e)
-		, Handler (\ (e :: SomeException) -> retry e)
-		]
+	runClient getaddr clientaction `catchNonAsync` retry
 	where
 		retry e = do
 			v' <- onretry e v
@@ -81,5 +80,5 @@ persistentClient getaddr v onretry clientaction =
 
 {- Catches only ClientError -}
 catchClientError :: IO () -> (ClientError -> IO ()) -> IO ()
-catchClientError io handler = do
+catchClientError io handler =
 	either handler return =<< (E.try io :: IO (Either ClientError ()))

Utility/Exception.hs

@@ -1,10 +1,12 @@
-{- Simple IO exception handling
+{- Simple IO exception handling (and some more)
  -
  - Copyright 2011-2012 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
+{-# LANGUAGE ScopedTypeVariables #-}
+
 module Utility.Exception where
 
 import Prelude hiding (catch)
@@ -34,3 +36,16 @@ catchIO = catch
 {- try specialized for IO errors only -}
 tryIO :: IO a -> IO (Either IOException a)
 tryIO = try
+
+{- Catches all exceptions except for async exceptions.
+ - This is often better to use than catching them all, so that
+ - ThreadKilled and UserInterrupt get through.
+ -}
+catchNonAsync :: IO a -> (SomeException -> IO a) -> IO a
+catchNonAsync a onerr = a `catches`
+	[ Handler (\ (e :: AsyncException) -> throw e)
+	, Handler (\ (e :: SomeException) -> onerr e)
+	]
+
+tryNonAsync :: IO a -> IO (Either SomeException a)
+tryNonAsync a = (Right <$> a) `catchNonAsync` (return . Left)