reorganized lockFiles

1 files changed, 8 insertions, 7 deletions

diff --git a/kiki.hs b/kiki.hs
index 414d185..e4c0dc4 100644
--- a/kiki.hs
+++ b/kiki.hs
@@ -723,17 +723,18 @@ readPacketsFromFile fname = do
     return $ decode input
 #endif
 
+-- | Attempts to lock each file in the list.
+-- Returns a list of locks and a list of filenames
+-- that could not be locked.
+lockFiles :: [FilePath] -> IO ( [(DotLock,FilePath)], [FilePath] )
 lockFiles fs = do
-    let dolock f = do
+    ls <- forM fs $ \f -> do
             lk <- dotlock_create f 0
-            let fail = return Nothing
-                dotake lk = do
+            v <- flip (maybe $ return Nothing) lk $ \lk -> do
                     e <- dotlock_take lk (-1)
-                    if e==0 then return (Just lk)
-                            else fail
-            v <- maybe fail dotake lk
+                    return $ if e==0 then Just lk
+                                     else Nothing
             return (v,f)
-    ls <- mapM dolock fs
     let (lks, fails) = partition (isJust . fst) ls
     return (map (\(lk,f)->(fromJust lk,f)) lks, map snd fails)