104 lines
2.8 KiB
Haskell
104 lines
2.8 KiB
Haskell
{- git-annex internal data types
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-
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- Most things should not need this, using Types and/or Annex instead.
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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 TypeInternals where
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import Control.Monad.State (StateT)
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import Data.String.Utils
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import qualified Data.Map as M
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import Test.QuickCheck
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import qualified GitRepo as Git
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import qualified GitQueue
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-- command-line flags
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type FlagName = String
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data Flag =
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FlagBool Bool |
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FlagString String
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deriving (Eq, Read, Show)
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-- git-annex's runtime state type doesn't really belong here,
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-- but it uses Backend, so has to be here to avoid a depends loop.
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data AnnexState = AnnexState {
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repo :: Git.Repo,
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backends :: [Backend],
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supportedBackends :: [Backend],
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flags :: M.Map FlagName Flag,
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repoqueue :: GitQueue.Queue
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} deriving (Show)
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-- git-annex's monad
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type Annex = StateT AnnexState IO
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-- annexed filenames are mapped through a backend into keys
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type KeyName = String
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type BackendName = String
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data Key = Key (BackendName, KeyName) deriving (Eq, Ord)
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-- constructs a key in a backend
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genKey :: Backend -> KeyName -> Key
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genKey b f = Key (name b,f)
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-- show a key to convert it to a string; the string includes the
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-- name of the backend to avoid collisions between key strings
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instance Show Key where
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show (Key (b, k)) = b ++ ":" ++ k
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instance Read Key where
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readsPrec _ s = [(Key (b,k), "")]
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where
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l = split ":" s
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b = if null l then "" else head l
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k = join ":" $ drop 1 l
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-- for quickcheck
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instance Arbitrary Key where
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arbitrary = do
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backendname <- arbitrary
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keyname <- arbitrary
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return $ Key (backendname, keyname)
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prop_idempotent_key_read_show :: Key -> Bool
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prop_idempotent_key_read_show k
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-- backend names will never contain colons
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| elem ':' (backendName k) = True
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| otherwise = k == (read $ show k)
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backendName :: Key -> BackendName
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backendName (Key (b,_)) = b
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keyName :: Key -> KeyName
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keyName (Key (_,k)) = k
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-- this structure represents a key-value backend
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data Backend = Backend {
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-- name of this backend
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name :: String,
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-- converts a filename to a key
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getKey :: FilePath -> Annex (Maybe Key),
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-- stores a file's contents to a key
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storeFileKey :: FilePath -> Key -> Annex Bool,
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-- retrieves a key's contents to a file
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retrieveKeyFile :: Key -> FilePath -> Annex Bool,
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-- removes a key, optionally checking that enough copies are stored
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-- elsewhere
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removeKey :: Key -> Maybe Int -> Annex Bool,
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-- checks if a backend is storing the content of a key
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hasKey :: Key -> Annex Bool,
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-- called during fsck to check a key
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-- (second parameter may be the number of copies that there should
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-- be of the key)
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fsckKey :: Key -> Maybe Int -> Annex Bool
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}
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instance Show Backend where
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show backend = "Backend { name =\"" ++ name backend ++ "\" }"
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instance Eq Backend where
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a == b = name a == name b
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