bring back some deleted functions that git-repair uses

diff --git a/Utility/FileMode.hs b/Utility/FileMode.hs
index 1e9b634836d6573b14b01743bc8365066eb2d029..efef5fa258e7f8e1ef9d7aed61ccd7c2abd0e858 100644 (file)
--- a/Utility/FileMode.hs
+++ b/Utility/FileMode.hs
@@ -27,12 +27,24 @@ import Utility.Exception
 
 {- Applies a conversion function to a file's mode. -}
 modifyFileMode :: FilePath -> (FileMode -> FileMode) -> IO ()
-modifyFileMode f convert = do
+modifyFileMode f convert = void $ modifyFileMode' f convert
+
+modifyFileMode' :: FilePath -> (FileMode -> FileMode) -> IO FileMode
+modifyFileMode' f convert = do
        s <- getFileStatus f
        let old = fileMode s
        let new = convert old
        when (new /= old) $
                setFileMode f new
+       return old
+
+{- Runs an action after changing a file's mode, then restores the old mode. -}
+withModifiedFileMode :: FilePath -> (FileMode -> FileMode) -> IO a -> IO a
+withModifiedFileMode file convert a = bracket setup cleanup go
+  where
+       setup = modifyFileMode' file convert
+       cleanup oldmode = modifyFileMode file (const oldmode)
+       go _ = a
 
 {- Adds the specified FileModes to the input mode, leaving the rest
  - unchanged. -}