another memory optimisation

This time memory leaked if lots of UUIDs needed to be pretty-printed, as in
a get or drop of many files. Essentially the same strict read buffering
problem that affected the LocationLog underneath though.

uuidMap really could stand to be cached, as the uuid log is read many times
in this case. But it is a fairly edge case.

1 files changed, 6 insertions, 4 deletions

diff --git a/UUID.hs b/UUID.hs
index f2235e4b6..20f85bae1 100644
--- a/UUID.hs
+++ b/UUID.hs
@@ -26,6 +26,7 @@ import System.Cmd.Utils
 import System.IO
 import System.Directory
 import qualified Data.Map as M
+import System.Posix.Process
 
 import qualified GitRepo as Git
 import Types
@@ -111,8 +112,11 @@ describeUUID uuid desc = do
 	m <- uuidMap
 	let m' = M.insert uuid desc m
 	log <- uuidLog
+	pid <- liftIO $ getProcessID
+        let tmplog = log ++ ".tmp" ++ show pid
 	liftIO $ createDirectoryIfMissing True (parentDir log)
-	liftIO $ withFileLocked log WriteMode (\h -> hPutStr h $ serialize m')
+	liftIO $ writeFile tmplog $ serialize m'
+	liftIO $ renameFile tmplog log
 	where
 		serialize m = unlines $ map (\(u, d) -> u++" "++d) $ M.toList m
 
@@ -120,9 +124,7 @@ describeUUID uuid desc = do
 uuidMap :: Annex (M.Map UUID String)
 uuidMap = do
 	log <- uuidLog
-	s <- liftIO $ catch
-		(withFileLocked log ReadMode $ \h -> hGetContentsStrict h)
-		(\error -> return "")
+	s <- liftIO $ catch (readFile log) (\error -> return "")
 	return $ M.fromList $ map (\l -> pair l) $ lines s
 	where
 		pair l =