Minor refactoring

src/ATrade/Broker/Server.hs

@@ -98,12 +98,12 @@ notificationCallback state n = do
 
 tradeSinkHandler :: Context -> IORef BrokerServerState -> T.Text -> IO ()
 tradeSinkHandler c state tradeSinkEp = when (tradeSinkEp /= "") $
-    whileM_ (fmap killMvar (readIORef state) >>= fmap isNothing . tryReadMVar) $
+    whileM_ (not <$> wasKilled) $
       withSocket c Req (\sock -> do
         chan <- tradeSink <$> readIORef state
         connect sock $ T.unpack tradeSinkEp
         timeoutMv <- newEmptyMVar
-        whileM_ (andM [fmap killMvar (readIORef state) >>= fmap isNothing . tryReadMVar, isNothing <$> tryReadMVar timeoutMv]) $ do
+        whileM_ (andM [not <$> wasKilled, isNothing <$> tryReadMVar timeoutMv]) $ do
           threadDelay 500000
           maybeTrade <- tryReadChan chan
           case maybeTrade of
@@ -113,10 +113,10 @@ tradeSinkHandler c state tradeSinkEp = when (tradeSinkEp /= "") $
               events <- poll 5000 [Sock sock [In] Nothing]
               if not . L.null . L.head $ events
                 then void . receive $ sock -- anything will do
-                else putMVar timeoutMv ()
-        )
+                else putMVar timeoutMv ())
 
     where
+      wasKilled = fmap killMvar (readIORef state) >>= fmap isJust . tryReadMVar
       encodeTrade :: Trade -> B.ByteString
       encodeTrade = BL.toStrict . encode . convertTrade
       convertTrade trade = TradeSinkTrade {