git-annex/Backend/URL.hs
Joey Hess 13bbb61a51 add key stability checking interface
Needed for resuming from chunks.

Url keys are considered not stable. I considered treating url keys with a
known size as stable, but just don't feel that is enough information.
2014-07-27 12:33:46 -04:00

41 lines
859 B
Haskell

{- git-annex "URL" backend -- keys whose content is available from urls.
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Backend.URL (
backends,
fromUrl
) where
import Common.Annex
import Types.Backend
import Types.Key
import Backend.Utilities
backends :: [Backend]
backends = [backend]
backend :: Backend
backend = Backend
{ name = "URL"
, getKey = const $ return Nothing
, fsckKey = Nothing
, canUpgradeKey = Nothing
, fastMigrate = Nothing
-- The content of an url can change at any time, so URL keys are
-- not stable.
, isStableKey = const False
}
{- Every unique url has a corresponding key. -}
fromUrl :: String -> Maybe Integer -> Annex Key
fromUrl url size = do
n <- genKeyName url
return $ stubKey
{ keyName = n
, keyBackendName = "URL"
, keySize = size
}