stopp reader from reading from a dead connection

rename elementFromEvents to elements and transform it to a conduit
add proper failing case for pullElement
change pushing to dead connection to throw away element rather than throw an exception

src/Network/XMPP/Concurrent/Monad.hs

@@ -174,9 +174,8 @@ withConnection a = do
       Ex.catch ( do
                    (res, s') <- runStateT a s
                    atomically $ do
-                       _ <- tryPutTMVar write (sConPushBS s')
-                       _ <- tryPutTMVar stateRef s'
-                       return ()
+                       putTMVar write (sConPushBS s')
+                       putTMVar stateRef s'
                    return res
                )
              -- we treat all Exceptions as fatal

src/Network/XMPP/Concurrent/Threads.hs

@@ -47,9 +47,13 @@ readWorker messageC presenceC handlers stateRef =
         res <- liftIO $ Ex.catch ( do
                        -- we don't know whether pull will
                        -- necessarily be interruptible
-                       s <- liftIO . atomically $ readTMVar stateRef
+                       s <- liftIO . atomically $ do
+                            sr <- readTMVar stateRef
+                            when (sConnectionState sr == XmppConnectionClosed)
+                                 retry
+                            return sr
                        allowInterrupt
-                       Just <$> runStateT pullStanza s
+                       Just . fst <$> runStateT pullStanza s
                                  )
                    (\(Interrupt t) -> do
                         void $ handleInterrupts [t]
@@ -58,7 +62,7 @@ readWorker messageC presenceC handlers stateRef =
         liftIO . atomically $ do
           case res of
               Nothing -> return ()
-              Just (sta, _s) -> do
+              Just sta -> do
                 case sta of
                     MessageS  m -> do writeTChan messageC $ Right m
                                       _ <- readTChan messageC -- Sic!

src/Network/XMPP/Monad.hs

@@ -13,6 +13,7 @@ import           Control.Monad.State.Strict
 
 import           Data.ByteString as BS
 import           Data.Conduit
+import qualified Data.Conduit.List as CL
 import           Data.Conduit.BufferedSource
 import           Data.Conduit.Binary as CB
 import           Data.Text(Text)
@@ -50,7 +51,11 @@ pullSink snk = do
   return r
 
 pullElement :: XMPPConMonad Element
-pullElement = pullSink elementFromEvents
+pullElement = do
+    e <- pullSink (elements =$ CL.head)
+    case e of
+        Nothing -> liftIO $ Ex.throwIO XmppNoConnection
+        Just r -> return r
 
 pullPickle :: PU [Node] a -> XMPPConMonad a
 pullPickle p = do
@@ -94,7 +99,7 @@ xmppNoConnection :: XmppConnection
 xmppNoConnection = XmppConnection
                { sConSrc    = zeroSource
                , sRawSrc    = zeroSource
-               , sConPushBS = \_ -> Ex.throwIO $ XmppNoConnection
+               , sConPushBS = \_ -> return ()
                , sConHandle = Nothing
                , sFeatures  = SF Nothing [] []
                , sConnectionState = XmppConnectionClosed

src/Network/XMPP/Stream.hs

@@ -3,6 +3,7 @@
 
 module Network.XMPP.Stream where
 
+import qualified Control.Exception as Ex
 import           Control.Monad.Error
 import           Control.Monad.State.Strict
 
@@ -82,8 +83,11 @@ xmppStreamHeader = do
 
 
 xmppStreamFeatures :: StreamSink ServerFeatures
-xmppStreamFeatures = streamUnpickleElem pickleStreamFeatures
-                       =<< lift elementFromEvents
+xmppStreamFeatures = do
+    e <- lift $ elements =$ CL.head
+    case e of
+        Nothing -> liftIO $ Ex.throwIO XmppNoConnection
+        Just r -> streamUnpickleElem pickleStreamFeatures r
 
 -- Pickling
 

src/Network/XMPP/Types.hs

@@ -714,6 +714,7 @@ data XmppConnectionState = XmppConnectionClosed  -- ^ No connection at
                          | XmppConnectionSecured -- ^ Connection
                                                  -- established and
                                                  -- secured via TLS
+                           deriving (Show, Eq, Typeable)
 data XmppConnection = XmppConnection
                { sConSrc          :: Source IO Event
                , sRawSrc          :: Source IO BS.ByteString

src/Text/XML/Stream/Elements.hs

@@ -24,11 +24,14 @@ compressNodes (NodeContent (ContentText x) : NodeContent (ContentText y) : z) =
     compressNodes $ NodeContent (ContentText $ x `Text.append` y) : z
 compressNodes (x:xs) = x : compressNodes xs
 
-elementFromEvents :: R.MonadThrow m => C.Sink Event m Element
-elementFromEvents = do
-        x <- CL.peek
+elements :: R.MonadThrow m => C.Conduit Event m Element
+elements = do
+        x <- C.await
         case x of
-            Just (EventBeginElement n as) -> goE n as
+            Just (EventBeginElement n as) -> do
+                                                 goE n as >>= C.yield
+                                                 elements
+            Nothing -> return ()
             _ -> lift $ R.monadThrow $ InvalidEventStream $ "not an element: " ++ show x
   where
     many' f =
@@ -37,25 +40,22 @@ elementFromEvents = do
         go front = do
             x <- f
             case x of
-                Nothing -> return $ front []
-                Just y -> go (front . (:) y)
-    dropReturn x = CL.drop 1 >> return x
+                Left x -> return $ (x, front [])
+                Right y -> go (front . (:) y)
     goE n as = do
-        CL.drop 1
-        ns <- many' goN
-        y <- CL.head
+        (y, ns) <- many' goN
         if y == Just (EventEndElement n)
             then return $ Element n as $ compressNodes ns
             else lift $ R.monadThrow $ InvalidEventStream $ "Missing end element for " ++ show n ++ ", got: " ++ show y
     goN = do
-        x <- CL.peek
+        x <- await
         case x of
-            Just (EventBeginElement n as) -> (Just . NodeElement) <$> goE n as
-            Just (EventInstruction i) -> dropReturn $ Just $ NodeInstruction i
-            Just (EventContent c) -> dropReturn $ Just $ NodeContent c
-            Just (EventComment t) -> dropReturn $ Just $ NodeComment t
-            Just (EventCDATA t) -> dropReturn $ Just $ NodeContent $ ContentText t
-            _ -> return Nothing
+            Just (EventBeginElement n as) -> (Right . NodeElement) <$> goE n as
+            Just (EventInstruction i) -> return $ Right $ NodeInstruction i
+            Just (EventContent c) -> return $ Right $ NodeContent c
+            Just (EventComment t) -> return $ Right $ NodeComment t
+            Just (EventCDATA t) -> return $ Right $ NodeContent $ ContentText t
+            _ -> return $ Left x
 
 
 openElementToEvents :: Element -> [Event]