40ecf58d4b
This does not change the overall license of the git-annex program, which was already AGPL due to a number of sources files being AGPL already. Legally speaking, I'm adding a new license under which these files are now available; I already released their current contents under the GPL license. Now they're dual licensed GPL and AGPL. However, I intend for all my future changes to these files to only be released under the AGPL license, and I won't be tracking the dual licensing status, so I'm simply changing the license statement to say it's AGPL. (In some cases, others wrote parts of the code of a file and released it under the GPL; but in all cases I have contributed a significant portion of the code in each file and it's that code that is getting the AGPL license; the GPL license of other contributors allows combining with AGPL code.)
54 lines
1.6 KiB
Haskell
54 lines
1.6 KiB
Haskell
{- git-annex file replacing
|
|
-
|
|
- Copyright 2013-2015 Joey Hess <id@joeyh.name>
|
|
-
|
|
- Licensed under the GNU AGPL version 3 or higher.
|
|
-}
|
|
|
|
{-# LANGUAGE CPP #-}
|
|
|
|
module Annex.ReplaceFile where
|
|
|
|
import Annex.Common
|
|
import Annex.Tmp
|
|
import Utility.Tmp.Dir
|
|
import Utility.Path.Max
|
|
|
|
{- Replaces a possibly already existing file with a new version,
|
|
- atomically, by running an action.
|
|
-
|
|
- The action is passed the name of temp file, in a temp directory,
|
|
- which it can write to, and once done the temp file is moved into place
|
|
- and anything else in the temp directory is deleted.
|
|
-
|
|
- The action can throw an exception, in which case the temp directory
|
|
- will be deleted, and the existing file will be preserved.
|
|
-
|
|
- Throws an IO exception when it was unable to replace the file.
|
|
-}
|
|
replaceFile :: FilePath -> (FilePath -> Annex a) -> Annex a
|
|
replaceFile file action = withOtherTmp $ \othertmpdir -> do
|
|
#ifndef mingw32_HOST_OS
|
|
-- Use part of the filename as the template for the temp
|
|
-- directory. This does not need to be unique, but it
|
|
-- makes it more clear what this temp directory is for.
|
|
filemax <- liftIO $ fileNameLengthLimit othertmpdir
|
|
let basetmp = take (filemax `div` 2) (takeFileName file)
|
|
#else
|
|
-- Windows has limits on the whole path length, so keep
|
|
-- it short.
|
|
let basetmp = "t"
|
|
#endif
|
|
withTmpDirIn othertmpdir basetmp $ \tmpdir -> do
|
|
let tmpfile = tmpdir </> basetmp
|
|
r <- action tmpfile
|
|
liftIO $ replaceFileFrom tmpfile file
|
|
return r
|
|
|
|
replaceFileFrom :: FilePath -> FilePath -> IO ()
|
|
replaceFileFrom src dest = go `catchIO` fallback
|
|
where
|
|
go = moveFile src dest
|
|
fallback _ = do
|
|
createDirectoryIfMissing True $ parentDir dest
|
|
go
|