91 lines
2.8 KiB
Haskell
91 lines
2.8 KiB
Haskell
{- git-annex object file locations
|
|
-
|
|
- Copyright 2010-2019 Joey Hess <id@joeyh.name>
|
|
-
|
|
- Licensed under the GNU AGPL version 3 or higher.
|
|
-}
|
|
|
|
module Annex.DirHashes (
|
|
Hasher,
|
|
HashLevels(..),
|
|
objectHashLevels,
|
|
branchHashLevels,
|
|
branchHashDir,
|
|
dirHashes,
|
|
hashDirMixed,
|
|
hashDirLower,
|
|
display_32bits_as_dir
|
|
) where
|
|
|
|
import Data.Default
|
|
import Data.Bits
|
|
import qualified Data.List.NonEmpty as NE
|
|
import qualified Data.ByteArray as BA
|
|
import qualified Data.ByteArray.Encoding as BA
|
|
import qualified Data.ByteString as S
|
|
import qualified System.FilePath.ByteString as P
|
|
|
|
import Common
|
|
import Key
|
|
import Types.GitConfig
|
|
import Types.Difference
|
|
import Utility.Hash
|
|
import Utility.MD5
|
|
|
|
type Hasher = Key -> RawFilePath
|
|
|
|
-- Number of hash levels to use. 2 is the default.
|
|
newtype HashLevels = HashLevels Int
|
|
|
|
instance Default HashLevels where
|
|
def = HashLevels 2
|
|
|
|
objectHashLevels :: GitConfig -> HashLevels
|
|
objectHashLevels = configHashLevels OneLevelObjectHash
|
|
|
|
branchHashLevels :: GitConfig -> HashLevels
|
|
branchHashLevels = configHashLevels OneLevelBranchHash
|
|
|
|
configHashLevels :: Difference -> GitConfig -> HashLevels
|
|
configHashLevels d config
|
|
| hasDifference d (annexDifferences config) = HashLevels 1
|
|
| otherwise = def
|
|
|
|
branchHashDir :: GitConfig -> Key -> S.ByteString
|
|
branchHashDir = hashDirLower . branchHashLevels
|
|
|
|
{- Two different directory hashes may be used. The mixed case hash
|
|
- came first, and is fine, except for the problem of case-strict
|
|
- filesystems such as Linux VFAT (mounted with shortname=mixed),
|
|
- which do not allow using a directory "XX" when "xx" already exists.
|
|
- To support that, some git-annex repositories use the lower case-hash.
|
|
- All special remotes use the lower-case hash for new data, but old data
|
|
- may still use the mixed case hash. -}
|
|
dirHashes :: NE.NonEmpty (HashLevels -> Hasher)
|
|
dirHashes = hashDirLower NE.:| [hashDirMixed]
|
|
|
|
hashDirs :: HashLevels -> Int -> S.ByteString -> RawFilePath
|
|
hashDirs (HashLevels 1) sz s = P.addTrailingPathSeparator $ S.take sz s
|
|
hashDirs _ sz s = P.addTrailingPathSeparator $ h P.</> t
|
|
where
|
|
(h, t) = S.splitAt sz s
|
|
|
|
hashDirLower :: HashLevels -> Hasher
|
|
hashDirLower n k = hashDirs n 3 $ S.pack $ take 6 $ conv $
|
|
md5s $ serializeKey' $ nonChunkKey k
|
|
where
|
|
conv v = BA.unpack $
|
|
(BA.convertToBase BA.Base16 v :: BA.Bytes)
|
|
|
|
{- This was originally using Data.Hash.MD5 from MissingH. This new version
|
|
- is faster, but ugly as it has to replicate the 4 Word32's that produced. -}
|
|
hashDirMixed :: HashLevels -> Hasher
|
|
hashDirMixed n k = hashDirs n 2 $ S.pack $ take 4 $
|
|
concatMap display_32bits_as_dir $
|
|
encodeWord32 $ map fromIntegral $ BA.unpack $
|
|
Utility.Hash.md5s $ serializeKey' $ nonChunkKey k
|
|
where
|
|
encodeWord32 (b1:b2:b3:b4:rest) =
|
|
(shiftL b4 24 .|. shiftL b3 16 .|. shiftL b2 8 .|. b1)
|
|
: encodeWord32 rest
|
|
encodeWord32 _ = []
|