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{- git-annex backend list
- -}
module BackendList (
supportedBackends,
parseBackendList,
lookupBackendName
) where
import Types
-- When adding a new backend, import it here and add it to the list.
import qualified BackendFile
import qualified BackendChecksum
import qualified BackendUrl
supportedBackends =
[ BackendFile.backend
, BackendChecksum.backend
, BackendUrl.backend
]
{- Parses a string with a list of backend names into
- a list of Backend objects. If the list is empty,
- defaults to supportedBackends. -}
parseBackendList :: String -> [Backend]
parseBackendList s =
if (length s == 0)
then supportedBackends
else map (lookupBackendName) $ words s
{- Looks up a supported backed by name. -}
lookupBackendName :: String -> Backend
lookupBackendName s =
if ((length matches) /= 1)
then error $ "unknown backend " ++ s
else matches !! 0
where matches = filter (\b -> s == name b) supportedBackends
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