git-annex/Types/Remote.hs

65 lines
1.8 KiB
Haskell

{- git-annex remotes types
-
- Most things should not need this, using Remote instead
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Types.Remote where
import Control.Exception
import Data.Map as M
import qualified GitRepo as Git
import Types.Key
type RemoteConfig = M.Map String String
{- There are different types of remotes. -}
data RemoteType a = RemoteType {
-- human visible type name
typename :: String,
-- enumerates remotes of this type
enumerate :: a [Git.Repo],
-- generates a remote of this type
generate :: Git.Repo -> String -> Maybe RemoteConfig -> a (Remote a),
-- initializes or changes a remote
setup :: String -> RemoteConfig -> a RemoteConfig
}
{- An individual remote. -}
data Remote a = Remote {
-- each Remote has a unique uuid
uuid :: String,
-- each Remote has a human visible name
name :: String,
-- Remotes have a use cost; higher is more expensive
cost :: Int,
-- Transfers a key to the remote.
storeKey :: Key -> a Bool,
-- retrieves a key's contents to a file
retrieveKeyFile :: Key -> FilePath -> a Bool,
-- removes a key's contents
removeKey :: Key -> a Bool,
-- Checks if a key is present in the remote; if the remote
-- cannot be accessed returns a Left error.
hasKey :: Key -> a (Either IOException Bool),
-- Some remotes can check hasKey without an expensive network
-- operation.
hasKeyCheap :: Bool,
-- a Remote can have a persistent configuration store
config :: Maybe RemoteConfig
}
instance Show (Remote a) where
show remote = "Remote { name =\"" ++ name remote ++ "\" }"
-- two remotes are the same if they have the same uuid
instance Eq (Remote a) where
x == y = uuid x == uuid y
-- order remotes by cost
instance Ord (Remote a) where
compare x y = compare (cost x) (cost y)