git-annex/Utility/TempFile.hs

39 lines
1.2 KiB
Haskell

{- temp file functions
-
- Copyright 2010-2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.TempFile where
import IO (bracket)
import System.IO
import System.Posix.Process hiding (executeFile)
import System.Directory
import Utility.Misc
import Utility.Path
{- Runs an action like writeFile, writing to a temp file first and
- then moving it into place. The temp file is stored in the same
- directory as the final file to avoid cross-device renames. -}
viaTmp :: (FilePath -> String -> IO ()) -> FilePath -> String -> IO ()
viaTmp a file content = do
pid <- getProcessID
let tmpfile = file ++ ".tmp" ++ show pid
createDirectoryIfMissing True (parentDir file)
a tmpfile content
renameFile tmpfile file
{- Runs an action with a temp file, then removes the file. -}
withTempFile :: String -> (FilePath -> Handle -> IO a) -> IO a
withTempFile template a = bracket create remove use
where
create = do
tmpdir <- catchDefaultIO getTemporaryDirectory "."
openTempFile tmpdir template
remove (name, handle) = do
hClose handle
catchBoolIO (removeFile name >> return True)
use (name, handle) = a name handle