108 lines
2.8 KiB
Haskell
108 lines
2.8 KiB
Haskell
{- git-annex Key data type
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-
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- Most things should not need this, using Types instead
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-
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- Copyright 2011 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 Types.Key (
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Key(..),
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AssociatedFile,
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stubKey,
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key2file,
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file2key,
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prop_idempotent_key_encode,
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prop_idempotent_key_decode
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) where
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import System.Posix.Types
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import Common
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import Utility.QuickCheck
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{- A Key has a unique name, which is derived from a particular backend,
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- and may contain other optional metadata. -}
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data Key = Key
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{ keyName :: String
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, keyBackendName :: String
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, keySize :: Maybe Integer
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, keyMtime :: Maybe EpochTime
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} deriving (Eq, Ord, Read, Show)
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{- A filename may be associated with a Key. -}
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type AssociatedFile = Maybe FilePath
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stubKey :: Key
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stubKey = Key
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{ keyName = ""
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, keyBackendName = ""
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, keySize = Nothing
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, keyMtime = Nothing
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}
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fieldSep :: Char
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fieldSep = '-'
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{- Converts a key to a string that is suitable for use as a filename.
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- The name field is always shown last, separated by doubled fieldSeps,
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- and is the only field allowed to contain the fieldSep. -}
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key2file :: Key -> FilePath
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key2file Key { keyBackendName = b, keySize = s, keyMtime = m, keyName = n } =
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b +++ ('s' ?: s) +++ ('m' ?: m) +++ (fieldSep : n)
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where
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"" +++ y = y
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x +++ "" = x
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x +++ y = x ++ fieldSep:y
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c ?: (Just v) = c : show v
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_ ?: _ = ""
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file2key :: FilePath -> Maybe Key
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file2key s
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| key == Just stubKey || (keyName <$> key) == Just "" || (keyBackendName <$> key) == Just "" = Nothing
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| otherwise = key
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where
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key = startbackend stubKey s
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startbackend k v = sepfield k v addbackend
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sepfield k v a = case span (/= fieldSep) v of
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(v', _:r) -> findfields r $ a k v'
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_ -> Nothing
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findfields (c:v) (Just k)
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| c == fieldSep = Just $ k { keyName = v }
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| otherwise = sepfield k v $ addfield c
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findfields _ v = v
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addbackend k v = Just k { keyBackendName = v }
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addfield 's' k v = do
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sz <- readish v
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return $ k { keySize = Just sz }
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addfield 'm' k v = do
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mtime <- readish v
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return $ k { keyMtime = Just mtime }
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addfield _ _ _ = Nothing
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instance Arbitrary Key where
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arbitrary = Key
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<$> (listOf1 $ elements $ ['A'..'Z'] ++ ['a'..'z'] ++ ['0'..'9'] ++ "-_\r\n \t")
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<*> (listOf1 $ elements ['A'..'Z']) -- BACKEND
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<*> ((abs <$>) <$> arbitrary) -- size cannot be negative
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<*> arbitrary
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prop_idempotent_key_encode :: Key -> Bool
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prop_idempotent_key_encode k = Just k == (file2key . key2file) k
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prop_idempotent_key_decode :: FilePath -> Bool
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prop_idempotent_key_decode f
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| normalfieldorder = maybe True (\k -> key2file k == f) (file2key f)
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| otherwise = True
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where
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-- file2key will accept the fields in any order, so don't
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-- try the test unless the fields are in the normal order
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normalfieldorder = fields `isPrefixOf` "sm"
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fields = map (f !!) $ filter (< length f) $ map succ $
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elemIndices fieldSep f
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