82 lines
1.9 KiB
Haskell
82 lines
1.9 KiB
Haskell
{- git-annex UUID type
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-
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- Copyright 2011-2019 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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{-# LANGUAGE TypeSynonymInstances, FlexibleInstances, GeneralizedNewtypeDeriving #-}
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module Types.UUID where
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import qualified Data.ByteString as B
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import qualified Data.Map as M
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import qualified Data.UUID as U
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import Data.Maybe
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import Data.String
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import Data.ByteString.Builder
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import Utility.FileSystemEncoding
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import qualified Utility.SimpleProtocol as Proto
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-- A UUID is either an arbitrary opaque string, or UUID info may be missing.
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data UUID = NoUUID | UUID B.ByteString
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deriving (Eq, Ord, Show, Read)
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class FromUUID a where
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fromUUID :: UUID -> a
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class ToUUID a where
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toUUID :: a -> UUID
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instance FromUUID UUID where
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fromUUID = id
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instance ToUUID UUID where
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toUUID = id
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instance FromUUID B.ByteString where
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fromUUID (UUID u) = u
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fromUUID NoUUID = B.empty
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instance ToUUID B.ByteString where
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toUUID b
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| B.null b = NoUUID
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| otherwise = UUID b
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instance FromUUID String where
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fromUUID s = decodeBS' (fromUUID s)
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instance ToUUID String where
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toUUID s = toUUID (encodeBS' s)
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-- There is no matching FromUUID U.UUID because a git-annex UUID may
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-- be NoUUID or perhaps contain something not allowed in a canonical UUID.
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instance ToUUID U.UUID where
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toUUID = toUUID . U.toASCIIBytes
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buildUUID :: UUID -> Builder
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buildUUID (UUID b) = byteString b
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buildUUID NoUUID = mempty
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isUUID :: String -> Bool
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isUUID = isJust . U.fromString
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-- A description of a UUID.
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newtype UUIDDesc = UUIDDesc B.ByteString
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deriving (Eq, Monoid, Semigroup, IsString)
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fromUUIDDesc :: UUIDDesc -> String
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fromUUIDDesc (UUIDDesc d) = decodeBS d
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toUUIDDesc :: String -> UUIDDesc
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toUUIDDesc = UUIDDesc . encodeBS
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buildUUIDDesc :: UUIDDesc -> Builder
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buildUUIDDesc (UUIDDesc b) = byteString b
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type UUIDDescMap = M.Map UUID UUIDDesc
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instance Proto.Serializable UUID where
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serialize = fromUUID
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deserialize = Just . toUUID
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