git-annex/Backend/Utilities.hs
Joey Hess 6dd806f1ad
stop using MissingH for MD5
Cryptonite is faster and allocates less, and I want to get rid of
MissingH use.

Note that the new dependency on memory is free; it's a dependency of
cryptonite.

This commit was supported by the NSF-funded DataLad project.
2017-05-15 21:36:03 -04:00

31 lines
805 B
Haskell

{- git-annex backend utilities
-
- Copyright 2012 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Backend.Utilities where
import Annex.Common
import Utility.FileSystemEncoding
import Utility.Hash
{- Generates a keyName from an input string. Takes care of sanitizing it.
- If it's not too long, the full string is used as the keyName.
- Otherwise, it's truncated, and its md5 is prepended to ensure a unique
- key. -}
genKeyName :: String -> String
genKeyName s
-- Avoid making keys longer than the length of a SHA256 checksum.
| bytelen > sha256len =
truncateFilePath (sha256len - md5len - 1) s' ++ "-" ++
show (md5 (encodeBS s))
| otherwise = s'
where
s' = preSanitizeKeyName s
bytelen = length (decodeW8 s')
sha256len = 64
md5len = 32