131 lines
3.7 KiB
Haskell
131 lines
3.7 KiB
Haskell
{- git-annex key/value backends
|
|
-
|
|
- Copyright 2010 Joey Hess <joey@kitenet.net>
|
|
-
|
|
- Licensed under the GNU GPL version 3 or higher.
|
|
-}
|
|
|
|
module Backend (
|
|
BackendFile,
|
|
list,
|
|
orderedList,
|
|
genKey,
|
|
lookupFile,
|
|
chooseBackends,
|
|
lookupBackendName,
|
|
maybeLookupBackendName
|
|
) where
|
|
|
|
import Control.Monad.State (liftIO, when)
|
|
import System.IO.Error (try)
|
|
import System.FilePath
|
|
import System.Posix.Files
|
|
import Data.Maybe
|
|
|
|
import Locations
|
|
import qualified Git
|
|
import qualified Annex
|
|
import Types
|
|
import Types.Key
|
|
import qualified Types.Backend as B
|
|
import Messages
|
|
|
|
-- When adding a new backend, import it here and add it to the list.
|
|
import qualified Backend.WORM
|
|
import qualified Backend.SHA
|
|
import qualified Backend.URL
|
|
|
|
list :: [Backend Annex]
|
|
list = Backend.WORM.backends ++ Backend.SHA.backends ++ Backend.URL.backends
|
|
|
|
{- List of backends in the order to try them when storing a new key. -}
|
|
orderedList :: Annex [Backend Annex]
|
|
orderedList = do
|
|
l <- Annex.getState Annex.backends -- list is cached here
|
|
if not $ null l
|
|
then return l
|
|
else do
|
|
s <- getstandard
|
|
d <- Annex.getState Annex.forcebackend
|
|
handle d s
|
|
where
|
|
parseBackendList [] = list
|
|
parseBackendList s = map lookupBackendName $ words s
|
|
handle Nothing s = return s
|
|
handle (Just "") s = return s
|
|
handle (Just name) s = do
|
|
let l' = lookupBackendName name : s
|
|
Annex.changeState $ \state -> state { Annex.backends = l' }
|
|
return l'
|
|
getstandard = do
|
|
g <- Annex.gitRepo
|
|
return $ parseBackendList $
|
|
Git.configGet g "annex.backends" ""
|
|
|
|
{- Generates a key for a file, trying each backend in turn until one
|
|
- accepts it. -}
|
|
genKey :: FilePath -> Maybe (Backend Annex) -> Annex (Maybe (Key, Backend Annex))
|
|
genKey file trybackend = do
|
|
bs <- orderedList
|
|
let bs' = maybe bs (: bs) trybackend
|
|
genKey' bs' file
|
|
genKey' :: [Backend Annex] -> FilePath -> Annex (Maybe (Key, Backend Annex))
|
|
genKey' [] _ = return Nothing
|
|
genKey' (b:bs) file = do
|
|
r <- (B.getKey b) file
|
|
case r of
|
|
Nothing -> genKey' bs file
|
|
Just k -> return $ Just (k, b)
|
|
|
|
{- Looks up the key and backend corresponding to an annexed file,
|
|
- by examining what the file symlinks to. -}
|
|
lookupFile :: FilePath -> Annex (Maybe (Key, Backend Annex))
|
|
lookupFile file = do
|
|
tl <- liftIO $ try getsymlink
|
|
case tl of
|
|
Left _ -> return Nothing
|
|
Right l -> makekey l
|
|
where
|
|
getsymlink = do
|
|
l <- readSymbolicLink file
|
|
return $ takeFileName l
|
|
makekey l = maybe (return Nothing) (makeret l) (fileKey l)
|
|
makeret l k =
|
|
case maybeLookupBackendName bname of
|
|
Just backend -> return $ Just (k, backend)
|
|
Nothing -> do
|
|
when (isLinkToAnnex l) $
|
|
warning skip
|
|
return Nothing
|
|
where
|
|
bname = keyBackendName k
|
|
skip = "skipping " ++ file ++
|
|
" (unknown backend " ++ bname ++ ")"
|
|
|
|
type BackendFile = (Maybe (Backend Annex), FilePath)
|
|
|
|
{- Looks up the backends that should be used for each file in a list.
|
|
- That can be configured on a per-file basis in the gitattributes file.
|
|
-}
|
|
chooseBackends :: [FilePath] -> Annex [BackendFile]
|
|
chooseBackends fs = do
|
|
g <- Annex.gitRepo
|
|
forced <- Annex.getState Annex.forcebackend
|
|
if isJust forced
|
|
then do
|
|
l <- orderedList
|
|
return $ map (\f -> (Just $ head l, f)) fs
|
|
else do
|
|
pairs <- liftIO $ Git.checkAttr g "annex.backend" fs
|
|
return $ map (\(f,b) -> (maybeLookupBackendName b, f)) pairs
|
|
|
|
{- Looks up a backend by name. May fail if unknown. -}
|
|
lookupBackendName :: String -> Backend Annex
|
|
lookupBackendName s = fromMaybe unknown $ maybeLookupBackendName s
|
|
where
|
|
unknown = error $ "unknown backend " ++ s
|
|
maybeLookupBackendName :: String -> Maybe (Backend Annex)
|
|
maybeLookupBackendName s
|
|
| length matches == 1 = Just $ head matches
|
|
| otherwise = Nothing
|
|
where matches = filter (\b -> s == B.name b) list
|