git-annex/Utility/Base64.hs
Joey Hess 16c798b5ef
switch MetaValue to ByteString and MetaField to Text
MetaField was already limited to alphanumerics, so it makes sense to use
Text for it.

Note that technically a UUID can contain invalid UTF-8, and so
remoteMetaDataPrefix's use of T.pack . fromUUID could replace non-UTF8
values with '?' or whatever. In practice, a UUID is usually also text,
I only kept open the possibility of it containing invalid UTF-8 to avoid
breaking parsing of strange UUIDs in git-annex branch files. So, I
decided to let this edge case slip by.

Have not updated the rest of the code base yet for this change, as the
change took 2.5 hours longer than I expected to get working properly.
2019-01-07 14:18:24 -04:00

49 lines
1.4 KiB
Haskell

{- Simple Base64 encoding
-
- Copyright 2011-2019 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.Base64 where
import Utility.FileSystemEncoding
import qualified "sandi" Codec.Binary.Base64 as B64
import Data.Maybe
import qualified Data.ByteString as B
import Data.ByteString.UTF8 (fromString, toString)
import Data.Char
-- | This uses the FileSystemEncoding, so it can be used on Strings
-- that repesent filepaths containing arbitrarily encoded characters.
toB64 :: String -> String
toB64 = toString . B64.encode . encodeBS
toB64' :: B.ByteString -> B.ByteString
toB64' = B64.encode
fromB64Maybe :: String -> Maybe String
fromB64Maybe s = either (const Nothing) (Just . decodeBS)
(B64.decode $ fromString s)
fromB64Maybe' :: B.ByteString -> Maybe (B.ByteString)
fromB64Maybe' = either (const Nothing) Just . B64.decode
fromB64 :: String -> String
fromB64 = fromMaybe bad . fromB64Maybe
where
bad = error "bad base64 encoded data"
fromB64' :: B.ByteString -> B.ByteString
fromB64' = fromMaybe bad . fromB64Maybe'
where
bad = error "bad base64 encoded data"
-- Only ascii strings are tested, because an arbitrary string may contain
-- characters not encoded using the FileSystemEncoding, which would thus
-- not roundtrip, as decodeBS always generates an output encoded that way.
prop_b64_roundtrips :: String -> Bool
prop_b64_roundtrips s
| all (isAscii) s = s == decodeBS (fromB64' (toB64' (encodeBS s)))
| otherwise = True