git-annex/Backend/WORM.hs
Joey Hess e7652b0997
implement URL to VURL migration
This needs the content to be present in order to hash it. But it's not
possible for a module used by Backend.URL to call inAnnex because that
would entail a dependency loop. So instead, rely on the fact that
Command.Migrate calls inAnnex before performing a migration.

But, Command.ExamineKey calls fastMigrate and the key may or may not
exist, and it's not wanting to actually perform a migration in any case.
To handle that, had to add an additional value to fastMigrate to
indicate whether the content is inAnnex.

Factored generateEquivilantKey out of Remote.Web.

Note that migrateFromURLToVURL hardcodes use of the SHA256E backend.
It would have been difficult not to, given all the dependency loop
issues. But --backend and annex.backend are used to tell git-annex
migrate to use VURL in any case, so there's no config knob that
the user could expect to configure that.

Sponsored-by: Brock Spratlen on Patreon
2024-03-01 16:42:02 -04:00

70 lines
2.1 KiB
Haskell

{- git-annex "WORM" backend -- Write Once, Read Many
-
- Copyright 2010 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Backend.WORM (backends) where
import Annex.Common
import Types.Key
import Types.Backend
import Types.KeySource
import Backend.Utilities
import Git.FilePath
import Utility.Metered
import qualified Utility.RawFilePath as R
import qualified Data.ByteString.Char8 as S8
import qualified Data.ByteString.Short as S (toShort, fromShort)
import System.PosixCompat.Files (modificationTime)
backends :: [Backend]
backends = [backend]
backend :: Backend
backend = Backend
{ backendVariety = WORMKey
, genKey = Just keyValue
, verifyKeyContent = Nothing
, verifyKeyContentIncrementally = Nothing
, canUpgradeKey = Just needsUpgrade
, fastMigrate = Just removeProblemChars
, isStableKey = const True
, isCryptographicallySecure = False
, isCryptographicallySecureKey = const (pure False)
}
{- The key includes the file size, modification time, and the
- original filename relative to the top of the git repository.
-}
keyValue :: KeySource -> MeterUpdate -> Annex Key
keyValue source _ = do
let f = contentLocation source
stat <- liftIO $ R.getFileStatus f
sz <- liftIO $ getFileSize' f stat
relf <- fromRawFilePath . getTopFilePath
<$> inRepo (toTopFilePath $ keyFilename source)
return $ mkKey $ \k -> k
{ keyName = genKeyName relf
, keyVariety = WORMKey
, keySize = Just sz
, keyMtime = Just $ modificationTime stat
}
{- Old WORM keys could contain spaces and carriage returns,
- and can be upgraded to remove them. -}
needsUpgrade :: Key -> Bool
needsUpgrade key =
any (`S8.elem` S.fromShort (fromKey keyName key)) [' ', '\r']
removeProblemChars :: Key -> Backend -> AssociatedFile -> Bool -> Annex (Maybe Key)
removeProblemChars oldkey newbackend _ _
| migratable = return $ Just $ alterKey oldkey $ \d -> d
{ keyName = S.toShort $ encodeBS $ reSanitizeKeyName $ decodeBS $ S.fromShort $ keyName d }
| otherwise = return Nothing
where
migratable = oldvariety == newvariety
oldvariety = fromKey keyVariety oldkey
newvariety = backendVariety newbackend