7f7c31df1c
Now there's a Config type, that's extracted from the git config at startup. Note that laziness means that individual config values are only looked up and parsed on demand, and so we get implicit memoization for all of them. So this is not only prettier and more type safe, it optimises several places that didn't have explicit memoization before. As well as getting rid of the ugly explicit memoization code. Not yet done for annex.<remote>.* configuration settings.
111 lines
3.2 KiB
Haskell
111 lines
3.2 KiB
Haskell
{- git-annex key/value backends
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-
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- Copyright 2010 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Backend (
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list,
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orderedList,
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genKey,
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lookupFile,
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chooseBackend,
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lookupBackendName,
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maybeLookupBackendName
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) where
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import System.Posix.Files
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import Common.Annex
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import qualified Annex
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import Annex.CheckAttr
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import Types.Key
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import Types.KeySource
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import qualified Types.Backend as B
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-- When adding a new backend, import it here and add it to the list.
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import qualified Backend.SHA
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import qualified Backend.WORM
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import qualified Backend.URL
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list :: [Backend]
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list = Backend.SHA.backends ++ Backend.WORM.backends ++ Backend.URL.backends
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{- List of backends in the order to try them when storing a new key. -}
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orderedList :: Annex [Backend]
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orderedList = do
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l <- Annex.getState Annex.backends -- list is cached here
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if not $ null l
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then return l
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else do
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f <- Annex.getState Annex.forcebackend
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case f of
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Just name | not (null name) ->
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return [lookupBackendName name]
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_ -> do
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l' <- gen . annexBackends <$> Annex.getConfig
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Annex.changeState $ \s -> s { Annex.backends = l' }
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return l'
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where
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gen [] = list
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gen l = map lookupBackendName l
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{- Generates a key for a file, trying each backend in turn until one
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- accepts it. -}
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genKey :: KeySource -> Maybe Backend -> Annex (Maybe (Key, Backend))
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genKey source trybackend = do
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bs <- orderedList
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let bs' = maybe bs (: bs) trybackend
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genKey' bs' source
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genKey' :: [Backend] -> KeySource -> Annex (Maybe (Key, Backend))
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genKey' [] _ = return Nothing
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genKey' (b:bs) source = do
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r <- B.getKey b source
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case r of
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Nothing -> genKey' bs source
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Just k -> return $ Just (makesane k, b)
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where
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-- keyNames should not contain newline characters.
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makesane k = k { keyName = map fixbadchar (keyName k) }
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fixbadchar c
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| c == '\n' = '_'
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| otherwise = c
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{- Looks up the key and backend corresponding to an annexed file,
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- by examining what the file symlinks to. -}
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lookupFile :: FilePath -> Annex (Maybe (Key, Backend))
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lookupFile file = do
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tl <- liftIO $ tryIO $ readSymbolicLink file
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case tl of
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Left _ -> return Nothing
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Right l -> makekey l
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where
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makekey l = maybe (return Nothing) (makeret l) (fileKey $ takeFileName l)
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makeret l k = let bname = keyBackendName k in
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case maybeLookupBackendName bname of
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Just backend -> do
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return $ Just (k, backend)
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Nothing -> do
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when (isLinkToAnnex l) $ warning $
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"skipping " ++ file ++
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" (unknown backend " ++ bname ++ ")"
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return Nothing
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{- Looks up the backend that should be used for a file.
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- That can be configured on a per-file basis in the gitattributes file. -}
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chooseBackend :: FilePath -> Annex (Maybe Backend)
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chooseBackend f = Annex.getState Annex.forcebackend >>= go
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where
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go Nothing = maybeLookupBackendName <$> checkAttr "annex.backend" f
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go (Just _) = Just . Prelude.head <$> orderedList
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{- Looks up a backend by name. May fail if unknown. -}
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lookupBackendName :: String -> Backend
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lookupBackendName s = fromMaybe unknown $ maybeLookupBackendName s
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where
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unknown = error $ "unknown backend " ++ s
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maybeLookupBackendName :: String -> Maybe Backend
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maybeLookupBackendName s = headMaybe matches
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where
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matches = filter (\b -> s == B.name b) list
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