git-annex/Backend/SHA.hs
Joey Hess e0fdfb2e70 maintain set of files pendingAdd
Kqueue needs to remember which files failed to be added due to being open,
and retry them. This commit gets the data in place for such a retry thread.

Broke KeySource out into its own file, and added Eq and Ord instances
so it can be stored in a Set.
2012-06-20 16:31:46 -04:00

111 lines
2.9 KiB
Haskell

{- git-annex SHA backend
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Backend.SHA (backends) where
import Common.Annex
import qualified Annex
import Types.Backend
import Types.Key
import Types.KeySource
import qualified Build.SysConfig as SysConfig
type SHASize = Int
-- order is slightly significant; want SHA256 first, and more general
-- sizes earlier
sizes :: [Int]
sizes = [256, 1, 512, 224, 384]
backends :: [Backend]
backends = catMaybes $ map genBackend sizes ++ map genBackendE sizes
genBackend :: SHASize -> Maybe Backend
genBackend size
| isNothing (shaCommand size) = Nothing
| otherwise = Just b
where
b = Backend
{ name = shaName size
, getKey = keyValue size
, fsckKey = Just $ checkKeyChecksum size
}
genBackendE :: SHASize -> Maybe Backend
genBackendE size =
case genBackend size of
Nothing -> Nothing
Just b -> Just $ b
{ name = shaNameE size
, getKey = keyValueE size
}
shaCommand :: SHASize -> Maybe String
shaCommand 1 = SysConfig.sha1
shaCommand 256 = Just SysConfig.sha256
shaCommand 224 = SysConfig.sha224
shaCommand 384 = SysConfig.sha384
shaCommand 512 = SysConfig.sha512
shaCommand _ = Nothing
shaName :: SHASize -> String
shaName size = "SHA" ++ show size
shaNameE :: SHASize -> String
shaNameE size = shaName size ++ "E"
shaN :: SHASize -> FilePath -> Annex String
shaN size file = do
showAction "checksum"
liftIO $ pOpen ReadFromPipe command (toCommand [File file]) $ \h -> do
sha <- fst . separate (== ' ') <$> hGetLine h
if null sha
then error $ command ++ " parse error"
else return sha
where
command = fromJust $ shaCommand size
{- A key is a checksum of its contents. -}
keyValue :: SHASize -> KeySource -> Annex (Maybe Key)
keyValue size source = do
let file = contentLocation source
s <- shaN size file
stat <- liftIO $ getFileStatus file
return $ Just $ stubKey
{ keyName = s
, keyBackendName = shaName size
, keySize = Just $ fromIntegral $ fileSize stat
}
{- Extension preserving keys. -}
keyValueE :: SHASize -> KeySource -> Annex (Maybe Key)
keyValueE size source = keyValue size source >>= maybe (return Nothing) addE
where
addE k = return $ Just $ k
{ keyName = keyName k ++ extension
, keyBackendName = shaNameE size
}
naiveextension = takeExtension $ keyFilename source
extension
-- long or newline containing extensions are
-- probably not really an extension
| length naiveextension > 6 ||
'\n' `elem` naiveextension = ""
| otherwise = naiveextension
{- A key's checksum is checked during fsck. -}
checkKeyChecksum :: SHASize -> Key -> FilePath -> Annex Bool
checkKeyChecksum size key file = do
fast <- Annex.getState Annex.fast
present <- liftIO $ doesFileExist file
if not present || fast
then return True
else check <$> shaN size file
where
check s
| s == dropExtension (keyName key) = True
| otherwise = False