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Diffstat (limited to 'Annex/ReplaceFile.hs')
-rw-r--r-- | Annex/ReplaceFile.hs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/Annex/ReplaceFile.hs b/Annex/ReplaceFile.hs new file mode 100644 index 000000000..f0dfa5b27 --- /dev/null +++ b/Annex/ReplaceFile.hs @@ -0,0 +1,35 @@ +{- git-annex file replacing + - + - Copyright 2013 Joey Hess <joey@kitenet.net> + - + - Licensed under the GNU GPL version 3 or higher. + -} + +module Annex.ReplaceFile where + +import Common.Annex +import Annex.Perms + +{- Replaces a possibly already existing file with a new version, + - atomically, by running an action. + - + - The action is passed a temp file, which it can write to, and once + - done the temp file is moved into place. + -} +replaceFile :: FilePath -> (FilePath -> Annex ()) -> Annex () +replaceFile file a = do + tmpdir <- fromRepo gitAnnexTmpDir + createAnnexDirectory tmpdir + tmpfile <- liftIO $ do + (tmpfile, h) <- openTempFileWithDefaultPermissions tmpdir $ + takeFileName file + hClose h + return tmpfile + a tmpfile + liftIO $ do + r <- tryIO $ rename tmpfile file + case r of + Left _ -> do + createDirectoryIfMissing True $ parentDir file + rename tmpfile file + _ -> noop |