git-annex/Utility/FileMode.hs
Joey Hess 297bc648b9 make unused check branches and tags too
needs time and space optimisation
2011-09-28 16:43:10 -04:00

36 lines
1 KiB
Haskell

{- File mode utilities.
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.FileMode where
import System.Posix.Files
import System.Posix.Types
import Foreign (complement)
{- Removes a FileMode from a file.
- For example, call with otherWriteMode to chmod o-w -}
unsetFileMode :: FilePath -> FileMode -> IO ()
unsetFileMode f m = do
s <- getFileStatus f
setFileMode f $ fileMode s `intersectFileModes` complement m
{- Removes the write bits from a file. -}
preventWrite :: FilePath -> IO ()
preventWrite f = unsetFileMode f writebits
where
writebits = foldl unionFileModes ownerWriteMode
[groupWriteMode, otherWriteMode]
{- Turns a file's write bit back on. -}
allowWrite :: FilePath -> IO ()
allowWrite f = do
s <- getFileStatus f
setFileMode f $ fileMode s `unionFileModes` ownerWriteMode
{- Checks if a file mode indicates it's a symlink. -}
isSymLink :: FileMode -> Bool
isSymLink mode = symbolicLinkMode `intersectFileModes` mode == symbolicLinkMode