simplify base64 to only use ByteString

Note the use of fromString and toString from Data.ByteString.UTF8 dated
back to commit 9b93278e8a. Back then it
was using the dataenc package for base64, which operated on Word8 and
String. But with the switch to sandi, it uses ByteString, and indeed
fromB64' and toB64' were already using ByteString without that
complication. So I think there is no risk of such an encoding related
breakage.

I also tested the case that 9b93278e8a
fixed:

	git-annex metadata -s foo='a …' x
	git-annex metadata x
	metadata x
	  foo=a …

In Remote.Helper.Encryptable, it was avoiding using Utility.Base64
because of that UTF8 conversion. Since that's no longer done, it can
just use it now.

Annex/TaggedPush.hs

@@ -38,14 +38,14 @@ toTaggedBranch :: UUID -> Maybe String -> Git.Branch -> Git.Ref
 toTaggedBranch u info b = Git.Ref $ S.intercalate "/" $ catMaybes
 	[ Just "refs/synced"
 	, Just $ fromUUID u
-	, toB64' . encodeBS <$> info
+	, toB64 . encodeBS <$> info
 	, Just $ Git.fromRef' $ Git.Ref.base b
 	]
 
-fromTaggedBranch :: Git.Ref -> Maybe (UUID, Maybe String)
+fromTaggedBranch :: Git.Ref -> Maybe (UUID, Maybe S.ByteString)
 fromTaggedBranch b = case splitc '/' $ Git.fromRef b of
 	("refs":"synced":u:info:_base) ->
-		Just (toUUID u, fromB64Maybe info)
+		Just (toUUID u, fromB64Maybe (encodeBS info))
 	("refs":"synced":u:_base) ->
 		Just (toUUID u, Nothing)
 	_ -> Nothing

Creds.hs

@@ -100,10 +100,10 @@ setRemoteCredPair' pc encsetup gc storage mcreds = case mcreds of
 		cmd <- gpgCmd <$> Annex.getGitConfig
 		s <- liftIO $ encrypt cmd (pc, gc) cipher
 			(feedBytes $ L.pack $ encodeCredPair creds)
-			(readBytesStrictly $ return . S.unpack)
-		storeconfig' key (Accepted (toB64 s))
+			(readBytesStrictly return)
+		storeconfig' key (Accepted (decodeBS (toB64 s)))
 	storeconfig creds key Nothing =
-		storeconfig' key (Accepted (toB64 $ encodeCredPair creds))
+		storeconfig' key (Accepted (decodeBS $ toB64 $ encodeBS $ encodeCredPair creds))
 	
 	storeconfig' key val = return $ pc
 		{ parsedRemoteConfigMap = M.insert key (RemoteConfigValue val) (parsedRemoteConfigMap pc)
@@ -129,13 +129,13 @@ getRemoteCredPair c gc storage = maybe fromcache (return . Just) =<< fromenv
 		case (getval, mcipher) of
 			(Nothing, _) -> return Nothing
 			(Just enccreds, Just (cipher, storablecipher)) ->
-				fromenccreds enccreds cipher storablecipher
+				fromenccreds (encodeBS enccreds) cipher storablecipher
 			(Just bcreds, Nothing) ->
-				fromcreds $ fromB64 bcreds
+				fromcreds $ decodeBS $ fromB64 $ encodeBS bcreds
 	fromenccreds enccreds cipher storablecipher = do
 		cmd <- gpgCmd <$> Annex.getGitConfig
 		mcreds <- liftIO $ catchMaybeIO $ decrypt cmd (c, gc) cipher
-			(feedBytes $ L.pack $ fromB64 enccreds)
+			(feedBytes $ L.fromStrict $ fromB64 enccreds)
 			(readBytesStrictly $ return . S.unpack)
 		case mcreds of
 			Just creds -> fromcreds creds
@@ -146,7 +146,7 @@ getRemoteCredPair c gc storage = maybe fromcache (return . Just) =<< fromenv
 				case storablecipher of
 					SharedCipher {} -> showLongNote "gpg error above was caused by an old git-annex bug in credentials storage. Working around it.."
 					_ -> giveup "*** Insecure credentials storage detected for this remote! See https://git-annex.branchable.com/upgrades/insecure_embedded_creds/"
-				fromcreds $ fromB64 enccreds
+				fromcreds $ decodeBS $ fromB64 enccreds
 	fromcreds creds = case decodeCredPair creds of
 		Just credpair -> do
 			writeCacheCredPair credpair storage

Logs/ContentIdentifier/Pure.hs

@@ -41,7 +41,7 @@ buildContentIdentifierList l = case l of
   where
 	buildcid (ContentIdentifier c)
 		| S8.any (`elem` [':', '\r', '\n']) c || "!" `S8.isPrefixOf` c =
-			charUtf8 '!' <> byteString (toB64' c)
+			charUtf8 '!' <> byteString (toB64 c)
 		| otherwise = byteString c
 	go [] = mempty
 	go (c:[]) = buildcid c
@@ -58,7 +58,7 @@ parseContentIdentifierList = do
 	cidparser = do
 		b <- A8.takeWhile (/= ':')
 		return $ if "!" `S8.isPrefixOf` b
-			then ContentIdentifier $ fromMaybe b (fromB64Maybe' (S.drop 1 b))
+			then ContentIdentifier $ fromMaybe b (fromB64Maybe (S.drop 1 b))
 			else ContentIdentifier b
 	listparser first rest = ifM A8.atEnd
 		( return (first :| reverse rest)

Remote/Helper/Encryptable.hs

@@ -28,8 +28,6 @@ module Remote.Helper.Encryptable (
 
 import qualified Data.Map as M
 import qualified Data.Set as S
-import qualified "sandi" Codec.Binary.Base64 as B64
-import qualified Data.ByteString as B
 import Control.Concurrent.STM
 
 import Annex.Common
@@ -39,6 +37,7 @@ import Types.Crypto
 import Types.ProposedAccepted
 import qualified Annex
 import Annex.SpecialRemote.Config
+import Utility.Base64
 
 -- Used to ensure that encryption has been set up before trying to
 -- eg, store creds in the remote config that would need to use the
@@ -272,7 +271,7 @@ storeCipher cip = case cip of
 	(EncryptedCipher t _ ks) -> addcipher t . storekeys ks cipherkeysField
 	(SharedPubKeyCipher t ks) -> addcipher t . storekeys ks pubkeysField
   where
-	addcipher t = M.insert cipherField (Accepted (toB64bs t))
+	addcipher t = M.insert cipherField (Accepted (decodeBS (toB64 (encodeBS t))))
 	storekeys (KeyIds l) n = M.insert n (Accepted (intercalate "," l))
 
 {- Extracts an StorableCipher from a remote's configuration. -}
@@ -281,13 +280,13 @@ extractCipher c = case (getRemoteConfigValue cipherField c,
 			(getRemoteConfigValue cipherkeysField c <|> getRemoteConfigValue pubkeysField c),
 			getRemoteConfigValue encryptionField c) of
 	(Just t, Just ks, Just HybridEncryption) ->
-		Just $ EncryptedCipher (fromB64bs t) Hybrid (readkeys ks)
+		Just $ EncryptedCipher (decodeBS (fromB64 (encodeBS t))) Hybrid (readkeys ks)
 	(Just t, Just ks, Just PubKeyEncryption) ->
-		Just $ EncryptedCipher (fromB64bs t) PubKey (readkeys ks)
+		Just $ EncryptedCipher (decodeBS (fromB64 (encodeBS t))) PubKey (readkeys ks)
 	(Just t, Just ks, Just SharedPubKeyEncryption) ->
-		Just $ SharedPubKeyCipher (fromB64bs t) (readkeys ks)
+		Just $ SharedPubKeyCipher (decodeBS (fromB64 (encodeBS t))) (readkeys ks)
 	(Just t, Nothing, Just SharedEncryption) ->
-		Just $ SharedCipher (fromB64bs t)
+		Just $ SharedCipher (decodeBS (fromB64 (encodeBS t)))
 	_ -> Nothing
   where
 	readkeys = KeyIds . splitc ','
@@ -321,14 +320,3 @@ describeCipher c = case c of
 	(SharedPubKeyCipher _ ks) -> showkeys ks
   where
 	showkeys (KeyIds { keyIds = ks }) = "to gpg keys: " ++ unwords ks
-
-{- Not using Utility.Base64 because these "Strings" are really
- - bags of bytes and that would convert to unicode and not round-trip
- - cleanly. -}
-toB64bs :: String -> String
-toB64bs = w82s . B.unpack . B64.encode . B.pack . s2w8
-
-fromB64bs :: String -> String
-fromB64bs s = either (const bad) (w82s . B.unpack) (B64.decode $ B.pack $ s2w8 s)
-  where
-	bad = giveup "bad base64 encoded data"

Test.hs

@@ -77,7 +77,6 @@ import qualified Utility.Hash
 import qualified Utility.Scheduled
 import qualified Utility.Scheduled.QuickCheck
 import qualified Utility.HumanTime
-import qualified Utility.Base64
 import qualified Utility.Tmp.Dir
 import qualified Utility.FileSystemEncoding
 import qualified Utility.Aeson
@@ -184,7 +183,6 @@ properties = localOption (QuickCheckTests 1000) $ testGroup "QuickCheck" $
 	, testProperty "prop_viewPath_roundtrips" Annex.View.prop_viewPath_roundtrips
 	, testProperty "prop_view_roundtrips" Annex.View.prop_view_roundtrips
 	, testProperty "prop_viewedFile_rountrips" Annex.View.ViewedFile.prop_viewedFile_roundtrips
-	, testProperty "prop_b64_roundtrips" Utility.Base64.prop_b64_roundtrips
 	, testProperty "prop_standardGroups_parse" Logs.PreferredContent.prop_standardGroups_parse
 	] ++ map (uncurry testProperty) combos
   where

Types/MetaData.hs

@@ -137,14 +137,14 @@ instance MetaSerializable MetaValue where
 	serialize (MetaValue isset v) =
 		serialize isset <>
 		if B8.any (`elem` [' ', '\r', '\n']) v || "!" `B8.isPrefixOf` v
-			then "!" <> toB64' v
+			then "!" <> toB64 v
 			else v
 	deserialize b = do
 		(isset, b') <- B8.uncons b
 		case B8.uncons b' of
 			Just ('!', b'') -> MetaValue
 				<$> deserialize (B8.singleton isset)
-				<*> fromB64Maybe' b''
+				<*> fromB64Maybe b''
 			_ -> MetaValue
 				<$> deserialize (B8.singleton isset)
 				<*> pure b'

Utility/Base64.hs

@@ -1,55 +1,25 @@
 {- Simple Base64 encoding
  -
- - Copyright 2011-2019 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2023 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
 
-{-# LANGUAGE PackageImports #-}
-
 module Utility.Base64 where
 
-import Utility.FileSystemEncoding
-import Utility.QuickCheck
 import Utility.Exception
 
-import qualified "sandi" Codec.Binary.Base64 as B64
+import 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 represent filepaths containing arbitrarily encoded characters.
-toB64 :: String -> String
-toB64 = toString . B64.encode . encodeBS
+toB64 :: B.ByteString -> B.ByteString
+toB64 = B64.encode
 
-toB64' :: B.ByteString -> B.ByteString
-toB64' = B64.encode
+fromB64Maybe :: B.ByteString -> Maybe (B.ByteString)
+fromB64Maybe = either (const Nothing) Just . B64.decode
 
-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 :: B.ByteString -> B.ByteString
 fromB64 = fromMaybe bad . fromB64Maybe
   where
 	bad = giveup "bad base64 encoded data"
-
-fromB64' :: B.ByteString -> B.ByteString
-fromB64' = fromMaybe bad . fromB64Maybe'
-  where
-	bad = giveup "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 :: TestableString -> Bool
-prop_b64_roundtrips ts
-	| all (isAscii) s = s == decodeBS (fromB64' (toB64' (encodeBS s)))
-	| otherwise = True
-  where
-	s = fromTestableString ts