git-annex/Utility/Directory.hs
Joey Hess 146c36ca54 IO exception rework
ghc 7.4 comaplains about use of System.IO.Error to catch exceptions.
Ok, use Control.Exception, with variants specialized to only catch IO
exceptions.
2012-02-03 16:47:24 -04:00

50 lines
1.3 KiB
Haskell

{- directory manipulation
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Directory where
import System.IO.Error
import System.Posix.Files
import System.Directory
import Control.Exception (throw)
import Control.Monad
import Control.Monad.IfElse
import Utility.SafeCommand
import Utility.TempFile
import Utility.Exception
{- Moves one filename to another.
- First tries a rename, but falls back to moving across devices if needed. -}
moveFile :: FilePath -> FilePath -> IO ()
moveFile src dest = tryIO (rename src dest) >>= onrename
where
onrename (Right _) = return ()
onrename (Left e)
| isPermissionError e = rethrow
| isDoesNotExistError e = rethrow
| otherwise = do
-- copyFile is likely not as optimised as
-- the mv command, so we'll use the latter.
-- But, mv will move into a directory if
-- dest is one, which is not desired.
whenM (isdir dest) rethrow
viaTmp mv dest undefined
where
rethrow = throw e
mv tmp _ = do
ok <- boolSystem "mv" [Param "-f",
Param src, Param tmp]
unless ok $ do
-- delete any partial
_ <- tryIO $ removeFile tmp
rethrow
isdir f = do
r <- tryIO $ getFileStatus f
case r of
(Left _) -> return False
(Right s) -> return $ isDirectory s