improve with continuation

no behavior change

diff --git a/Database/Handle.hs b/Database/Handle.hs
index 349dbca30d54ab3d399bba7896bceb050d06840b..b2ae6ed5a7431295bb2fd6c7fcee2ef8ba8d4792 100644 (file)
--- a/Database/Handle.hs
+++ b/Database/Handle.hs
@@ -132,33 +132,29 @@ data Job
        | CloseJob
 
 workerThread :: T.Text -> TableName -> MVar Job -> IO ()
-workerThread db tablename jobs = go
+workerThread db tablename jobs = newconn
   where
-       go = do
+       newconn = do
                v <- tryNonAsync (runSqliteRobustly tablename db loop)
                case v of
                        Left e -> hPutStrLn stderr $
                                "sqlite worker thread crashed: " ++ show e
-                       Right True -> go
-                       Right False -> return ()
+                       Right cont -> cont
        
-       getjob :: IO (Either BlockedIndefinitelyOnMVar Job)
-       getjob = try $ takeMVar jobs
-
        loop = do
                job <- liftIO getjob
                case job of
                        -- Exception is thrown when the MVar is garbage
                        -- collected, which means the whole DbHandle
                        -- is not used any longer. Shutdown cleanly.
-                       Left BlockedIndefinitelyOnMVar -> return False
-                       Right CloseJob -> return False
+                       Left BlockedIndefinitelyOnMVar -> return (return ())
+                       Right CloseJob -> return (return ())
                        Right (QueryJob a) -> a >> loop
                        Right (ChangeJob a) -> do
                                a
                                -- Exit this sqlite connection so the
                                -- database gets updated on disk.
-                               return True
+                               return newconn
                        -- Change is run in a separate database connection
                        -- since sqlite only supports a single writer at a
                        -- time, and it may crash the database connection
@@ -169,7 +165,10 @@ workerThread db tablename jobs = go
                                -- change that was just written, using 
                                -- a different db handle, is immediately
                                -- visible to queries.
-                               return True
+                               return newconn
+       
+       getjob :: IO (Either BlockedIndefinitelyOnMVar Job)
+       getjob = try $ takeMVar jobs
        
 -- Like runSqlite, but more robust.
 --