4c1e3210fa
It takes a single key-value backend, rather than the unncessary and confusing list. The old option still works if set. Simplified some old old code too. This commit was sponsored by Thomas Hochstein on Patreon.
97 lines
2.9 KiB
Haskell
97 lines
2.9 KiB
Haskell
{- git-annex key/value backends
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-
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- Copyright 2010-2017 Joey Hess <id@joeyh.name>
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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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defaultBackend,
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genKey,
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getBackend,
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chooseBackend,
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lookupBackendVariety,
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maybeLookupBackendVariety,
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isStableKey,
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) where
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import Annex.Common
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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.Hash
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import qualified Backend.WORM
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import qualified Backend.URL
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import qualified Data.Map as M
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list :: [Backend]
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list = Backend.Hash.backends ++ Backend.WORM.backends ++ Backend.URL.backends
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{- Backend to use by default when generating a new key. -}
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defaultBackend :: Annex Backend
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defaultBackend = maybe cache return =<< Annex.getState Annex.backend
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where
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cache = do
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n <- maybe (annexBackend <$> Annex.getGitConfig) (return . Just)
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=<< Annex.getState Annex.forcebackend
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let b = case n of
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Just name | valid name -> lookupname name
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_ -> Prelude.head list
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Annex.changeState $ \s -> s { Annex.backend = Just b }
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return b
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valid name = not (null name)
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lookupname = lookupBackendVariety . parseKeyVariety
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{- Generates a key for a file. -}
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genKey :: KeySource -> Maybe Backend -> Annex (Maybe (Key, Backend))
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genKey source preferredbackend = do
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b <- maybe defaultBackend return preferredbackend
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r <- B.getKey b source
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return $ case r of
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Nothing -> Nothing
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Just k -> 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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getBackend :: FilePath -> Key -> Annex (Maybe Backend)
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getBackend file k = case maybeLookupBackendVariety (keyVariety k) of
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Just backend -> return $ Just backend
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Nothing -> do
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warning $ "skipping " ++ file ++ " (unknown backend " ++ formatKeyVariety (keyVariety k) ++ ")"
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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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- or forced with --backend. -}
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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 = maybeLookupBackendVariety . parseKeyVariety
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<$> checkAttr "annex.backend" f
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go (Just _) = Just <$> defaultBackend
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{- Looks up a backend by variety. May fail if unsupported or disabled. -}
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lookupBackendVariety :: KeyVariety -> Backend
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lookupBackendVariety v = fromMaybe unknown $ maybeLookupBackendVariety v
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where
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unknown = giveup $ "unknown backend " ++ formatKeyVariety v
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maybeLookupBackendVariety :: KeyVariety -> Maybe Backend
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maybeLookupBackendVariety v = M.lookup v varietyMap
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varietyMap :: M.Map KeyVariety Backend
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varietyMap = M.fromList $ zip (map B.backendVariety list) list
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isStableKey :: Key -> Bool
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isStableKey k = maybe False (`B.isStableKey` k)
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(maybeLookupBackendVariety (keyVariety k))
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