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|
{- git-annex internal data types
-
- Most things should not need this, using Types and/or Annex instead.
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module TypeInternals where
import Control.Monad.State (StateT)
import Data.String.Utils
import qualified Data.Map as M
import Test.QuickCheck
import qualified GitRepo as Git
import qualified GitQueue
-- command-line flags
type FlagName = String
data Flag =
FlagBool Bool |
FlagString String
deriving (Eq, Read, Show)
-- git-annex's runtime state type doesn't really belong here,
-- but it uses Backend, so has to be here to avoid a depends loop.
data AnnexState = AnnexState {
repo :: Git.Repo,
backends :: [Backend],
supportedBackends :: [Backend],
flags :: M.Map FlagName Flag,
repoqueue :: GitQueue.Queue
} deriving (Show)
-- git-annex's monad
type Annex = StateT AnnexState IO
-- annexed filenames are mapped through a backend into keys
type KeyName = String
type BackendName = String
data Key = Key (BackendName, KeyName) deriving (Eq, Ord)
-- constructs a key in a backend
genKey :: Backend -> KeyName -> Key
genKey b f = Key (name b,f)
-- show a key to convert it to a string; the string includes the
-- name of the backend to avoid collisions between key strings
instance Show Key where
show (Key (b, k)) = b ++ ":" ++ k
instance Read Key where
readsPrec _ s = [(Key (b,k), "")]
where
l = split ":" s
b = if null l then "" else head l
k = join ":" $ drop 1 l
-- for quickcheck
instance Arbitrary Key where
arbitrary = do
backendname <- arbitrary
keyname <- arbitrary
return $ Key (backendname, keyname)
prop_idempotent_key_read_show :: Key -> Bool
prop_idempotent_key_read_show k
-- backend names will never contain colons
| elem ':' (backendName k) = True
| otherwise = k == (read $ show k)
backendName :: Key -> BackendName
backendName (Key (b,_)) = b
keyName :: Key -> KeyName
keyName (Key (_,k)) = k
-- this structure represents a key-value backend
data Backend = Backend {
-- name of this backend
name :: String,
-- converts a filename to a key
getKey :: FilePath -> Annex (Maybe Key),
-- stores a file's contents to a key
storeFileKey :: FilePath -> Key -> Annex Bool,
-- retrieves a key's contents to a file
retrieveKeyFile :: Key -> FilePath -> Annex Bool,
-- removes a key, optionally checking that enough copies are stored
-- elsewhere
removeKey :: Key -> Maybe Int -> Annex Bool,
-- checks if a backend is storing the content of a key
hasKey :: Key -> Annex Bool,
-- called during fsck to check a key
-- (second parameter may be the number of copies that there should
-- be of the key)
fsckKey :: Key -> Maybe Int -> Annex Bool
}
instance Show Backend where
show backend = "Backend { name =\"" ++ name backend ++ "\" }"
instance Eq Backend where
a == b = name a == name b
|
