git-annex/Annex/VariantFile.hs
Joey Hess 40ecf58d4b
update licenses from GPL to AGPL
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.)
2019-03-13 15:48:14 -04:00

45 lines
1.4 KiB
Haskell

{- git-annex .variant files for automatic merge conflict resolution
-
- Copyright 2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Annex.VariantFile where
import Annex.Common
import Utility.Hash
import qualified Data.ByteString.Lazy as L
variantMarker :: String
variantMarker = ".variant-"
mkVariant :: FilePath -> String -> FilePath
mkVariant file variant = takeDirectory file
</> dropExtension (takeFileName file)
++ variantMarker ++ variant
++ takeExtension file
{- The filename to use when resolving a conflicted merge of a file,
- that points to a key.
-
- Something derived from the key needs to be included in the filename,
- but rather than exposing the whole key to the user, a very weak hash
- is used. There is a very real, although still unlikely, chance of
- conflicts using this hash.
-
- In the event that there is a conflict with the filename generated
- for some other key, that conflict will itself be handled by the
- conflicted merge resolution code. That case is detected, and the full
- key is used in the filename.
-}
variantFile :: FilePath -> Key -> FilePath
variantFile file key
| doubleconflict = mkVariant file (keyFile key)
| otherwise = mkVariant file (shortHash $ serializeKey' key)
where
doubleconflict = variantMarker `isInfixOf` file
shortHash :: L.ByteString -> String
shortHash = take 4 . show . md5