From d7833def6620f2cdc3971eab38f3620e050404fb Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Wed, 27 Nov 2019 16:54:11 -0400
Subject: [PATCH] use ByteString for git config

The parser and looking up config keys in the map should both be faster
due to using ByteString.

I had hoped this would speed up startup time, but any improvement to
that was too small to measure. Seems worth keeping though.

Note that the parser breaks up the ByteString, but a config map ends up
pointing to the config as read, which is retained in memory until every
value from it is no longer used. This can change memory usage
patterns marginally, but won't affect git-annex.
---
 Annex/Environment.hs                          |  2 +
 Annex/Fixup.hs                                |  5 +-
 Annex/Init.hs                                 |  1 +
 Annex/UUID.hs                                 |  4 +-
 Annex/Version.hs                              |  1 +
 CmdLine/GitAnnex.hs                           |  4 +-
 CmdLine/GitAnnex/Options.hs                   |  2 +-
 Config.hs                                     | 23 ++++--
 Config/Smudge.hs                              |  2 +
 Git/AutoCorrect.hs                            |  4 +-
 Git/Branch.hs                                 |  5 +-
 Git/Config.hs                                 | 76 ++++++++++++-------
 Git/ConfigTypes.hs                            |  9 ++-
 Git/Construct.hs                              |  5 +-
 Git/GCrypt.hs                                 | 20 +++--
 Git/Remote.hs                                 | 23 +++---
 Git/Types.hs                                  |  4 +-
 Remote.hs                                     |  8 +-
 Remote/GCrypt.hs                              | 18 +++--
 Remote/Git.hs                                 |  8 +-
 Remote/GitLFS.hs                              |  6 +-
 Remote/Helper/Special.hs                      | 10 ++-
 Test/Framework.hs                             |  4 +-
 Types/Difference.hs                           | 11 ++-
 Types/GitConfig.hs                            | 20 +++--
 Upgrade/V5/Direct.hs                          |  4 +-
 ...ze_by_converting_String_to_ByteString.mdwn |  2 -
 27 files changed, 176 insertions(+), 105 deletions(-)

diff --git a/Annex/Environment.hs b/Annex/Environment.hs
index ea9eda0339..0e101d2e76 100644
--- a/Annex/Environment.hs
+++ b/Annex/Environment.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Annex.Environment where
 
 import Annex.Common
diff --git a/Annex/Fixup.hs b/Annex/Fixup.hs
index d167086b09..4585433c72 100644
--- a/Annex/Fixup.hs
+++ b/Annex/Fixup.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Annex.Fixup where
 
 import Git.Types
@@ -17,6 +19,7 @@ import Utility.SafeCommand
 import Utility.Directory
 import Utility.Exception
 import Utility.Monad
+import Utility.FileSystemEncoding
 import Utility.PartialPrelude
 
 import System.IO
@@ -53,7 +56,7 @@ fixupDirect r@(Repo { location = l@(Local { gitdir = d, worktree = Nothing }) })
 		{ location = l { worktree = Just (parentDir d) }
 		, gitGlobalOpts = gitGlobalOpts r ++
 			[ Param "-c"
-			, Param $ coreBare ++ "=" ++ boolConfig False
+			, Param $ decodeBS' coreBare ++ "=" ++ boolConfig False
 			]
 		}
 fixupDirect r = r
diff --git a/Annex/Init.hs b/Annex/Init.hs
index a762bf690c..38847c4e0d 100644
--- a/Annex/Init.hs
+++ b/Annex/Init.hs
@@ -6,6 +6,7 @@
  -}
 
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Annex.Init (
 	ensureInitialized,
diff --git a/Annex/UUID.hs b/Annex/UUID.hs
index 98d0c5219b..23593a46f7 100644
--- a/Annex/UUID.hs
+++ b/Annex/UUID.hs
@@ -11,6 +11,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Annex.UUID (
 	getUUID,
 	getRepoUUID,
@@ -112,7 +114,7 @@ storeUUIDIn configfield = setConfig configfield . fromUUID
 {- Only sets the configkey in the Repo; does not change .git/config -}
 setUUID :: Git.Repo -> UUID -> IO Git.Repo
 setUUID r u = do
-	let s = show configkey ++ "=" ++ fromUUID u
+	let s = encodeBS' $ show configkey ++ "=" ++ fromUUID u
 	Git.Config.store s r
 
 -- Dummy uuid for the whole web. Do not alter.
diff --git a/Annex/Version.hs b/Annex/Version.hs
index 6e0fd4f530..e7cab2a3ac 100644
--- a/Annex/Version.hs
+++ b/Annex/Version.hs
@@ -6,6 +6,7 @@
  -}
 
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Annex.Version where
 
diff --git a/CmdLine/GitAnnex.hs b/CmdLine/GitAnnex.hs
index bfec6f6271..deb723cf1d 100644
--- a/CmdLine/GitAnnex.hs
+++ b/CmdLine/GitAnnex.hs
@@ -124,8 +124,8 @@ import qualified Command.WebApp
 import qualified Command.Test
 import qualified Command.FuzzTest
 import qualified Command.TestRemote
-import qualified Command.Benchmark
 -}
+import qualified Command.Benchmark
 
 cmds :: Parser TestOptions -> TestRunner -> MkBenchmarkGenerator -> [Command]
 cmds testoptparser testrunner mkbenchmarkgenerator = 
@@ -235,9 +235,9 @@ cmds testoptparser testrunner mkbenchmarkgenerator =
 	, Command.Test.cmd testoptparser testrunner
 	, Command.FuzzTest.cmd
 	, Command.TestRemote.cmd
+-}
 	, Command.Benchmark.cmd $
 		mkbenchmarkgenerator $ cmds testoptparser testrunner (\_ _ -> return noop)
--}
 	]
 
 run :: Parser TestOptions -> TestRunner -> MkBenchmarkGenerator -> [String] -> IO ()
diff --git a/CmdLine/GitAnnex/Options.hs b/CmdLine/GitAnnex/Options.hs
index 117a876edb..fc25b3c817 100644
--- a/CmdLine/GitAnnex/Options.hs
+++ b/CmdLine/GitAnnex/Options.hs
@@ -92,7 +92,7 @@ gitAnnexGlobalOptions = commonGlobalOptions ++
   where
 	setnumcopies n = Annex.changeState $ \s -> s { Annex.forcenumcopies = Just $ NumCopies n }
 	setuseragent v = Annex.changeState $ \s -> s { Annex.useragent = Just v }
-	setgitconfig v = Annex.adjustGitRepo $ \r -> Git.Config.store v $ 
+	setgitconfig v = Annex.adjustGitRepo $ \r -> Git.Config.store (encodeBS' v) $ 
 		r { gitGlobalOpts = gitGlobalOpts r ++ [Param "-c", Param v] }
 	setdesktopnotify v = Annex.changeState $ \s -> s { Annex.desktopnotify = Annex.desktopnotify s <> v }
 
diff --git a/Config.hs b/Config.hs
index cbd82e50f7..94a22f720a 100644
--- a/Config.hs
+++ b/Config.hs
@@ -6,6 +6,7 @@
  -}
 
 {-# LANGUAGE TypeSynonymInstances, FlexibleInstances #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Config where
 
@@ -22,25 +23,31 @@ import qualified Types.Remote as Remote
 import qualified Annex.SpecialRemote.Config as SpecialRemote
 
 import qualified Data.Map as M
+import qualified Data.ByteString as S
 
-type UnqualifiedConfigKey = String
-data ConfigKey = ConfigKey String
+type UnqualifiedConfigKey = S.ByteString
+
+newtype ConfigKey = ConfigKey S.ByteString
 
 instance Show ConfigKey where
-	show (ConfigKey s) = s
+	show (ConfigKey s) = decodeBS' s
 
 {- Looks up a setting in git config. This is not as efficient as using the
  - GitConfig type. -}
-getConfig :: ConfigKey -> String -> Annex String
+getConfig :: ConfigKey -> S.ByteString -> Annex S.ByteString
 getConfig (ConfigKey key) d = fromRepo $ Git.Config.get key d
 
-getConfigMaybe :: ConfigKey -> Annex (Maybe String)
+getConfigMaybe :: ConfigKey -> Annex (Maybe S.ByteString)
 getConfigMaybe (ConfigKey key) = fromRepo $ Git.Config.getMaybe key
 
 {- Changes a git config setting in both internal state and .git/config -}
 setConfig :: ConfigKey -> String -> Annex ()
 setConfig (ConfigKey key) value = do
-	inRepo $ Git.Command.run [Param "config", Param key, Param value]
+	inRepo $ Git.Command.run
+		[ Param "config"
+		, Param (decodeBS' key)
+		, Param value
+		]
 	reloadConfig
 
 reloadConfig :: Annex ()
@@ -68,11 +75,11 @@ instance RemoteNameable Remote.RemoteConfig where
 {- A per-remote config setting in git config. -}
 remoteConfig :: RemoteNameable r => r -> UnqualifiedConfigKey -> ConfigKey
 remoteConfig r key = ConfigKey $
-	"remote." ++ getRemoteName r ++ ".annex-" ++ key
+	"remote." <> encodeBS' (getRemoteName r) <> ".annex-" <> key
 
 {- A global annex setting in git config. -}
 annexConfig :: UnqualifiedConfigKey -> ConfigKey
-annexConfig key = ConfigKey $ "annex." ++ key
+annexConfig key = ConfigKey ("annex." <> key)
 
 {- Calculates cost for a remote. Either the specific default, or as configured 
  - by remote.<name>.annex-cost, or if remote.<name>.annex-cost-command
diff --git a/Config/Smudge.hs b/Config/Smudge.hs
index b81db28139..08568f57c9 100644
--- a/Config/Smudge.hs
+++ b/Config/Smudge.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Config.Smudge where
 
 import Annex.Common
diff --git a/Git/AutoCorrect.hs b/Git/AutoCorrect.hs
index c7b0fd2995..ac45a4b367 100644
--- a/Git/AutoCorrect.hs
+++ b/Git/AutoCorrect.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Git.AutoCorrect where
 
 import Common
@@ -44,7 +46,7 @@ fuzzymatches input showchoice choices = fst $ unzip $
  -}
 prepare :: String -> (c -> String) -> [c] -> Maybe Repo -> IO ()
 prepare input showmatch matches r =
-	case readish . Git.Config.get "help.autocorrect" "0" =<< r of
+	case readish . decodeBS' . Git.Config.get "help.autocorrect" "0" =<< r of
 		Just n
 			| n == 0 -> list
 			| n < 0 -> warn Nothing
diff --git a/Git/Branch.hs b/Git/Branch.hs
index ffd9a189d2..21103b65f6 100644
--- a/Git/Branch.hs
+++ b/Git/Branch.hs
@@ -6,6 +6,7 @@
  -}
 
 {-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Git.Branch where
 
@@ -135,8 +136,8 @@ applyCommitMode commitmode ps
 applyCommitModeForCommitTree :: CommitMode -> [CommandParam] -> Repo -> [CommandParam]
 applyCommitModeForCommitTree commitmode ps r
 	| commitmode == ManualCommit =
-		case (Git.Config.getMaybe "commit.gpgsign" r) of
-			Just s | Git.Config.isTrue s == Just True ->
+		case Git.Config.getMaybe "commit.gpgsign" r of
+			Just s | Git.Config.isTrue' s == Just True ->
 				Param "-S":ps
 			_ -> ps'
 	| otherwise = ps'
diff --git a/Git/Config.hs b/Git/Config.hs
index 9ebd4bd0f5..215c7b40c8 100644
--- a/Git/Config.hs
+++ b/Git/Config.hs
@@ -1,13 +1,17 @@
 {- git repository configuration handling
  -
- - Copyright 2010-2012 Joey Hess <id@joeyh.name>
+ - Copyright 2010-2019 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Git.Config where
 
 import qualified Data.Map as M
+import qualified Data.ByteString as S
+import qualified Data.ByteString.Char8 as S8
 import Data.Char
 
 import Common
@@ -18,15 +22,15 @@ import qualified Git.Construct
 import Utility.UserInfo
 
 {- Returns a single git config setting, or a default value if not set. -}
-get :: String -> String -> Repo -> String
+get :: S.ByteString -> S.ByteString -> Repo -> S.ByteString
 get key defaultValue repo = M.findWithDefault defaultValue key (config repo)
 
 {- Returns a list with each line of a multiline config setting. -}
-getList :: String -> Repo -> [String]
+getList :: S.ByteString -> Repo -> [S.ByteString]
 getList key repo = M.findWithDefault [] key (fullconfig repo)
 
 {- Returns a single git config setting, if set. -}
-getMaybe :: String -> Repo -> Maybe String
+getMaybe :: S.ByteString -> Repo -> Maybe S.ByteString
 getMaybe key repo = M.lookup key (config repo)
 
 {- Runs git config and populates a repo with its config.
@@ -79,14 +83,14 @@ global = do
 {- Reads git config from a handle and populates a repo with it. -}
 hRead :: Repo -> Handle -> IO Repo
 hRead repo h = do
-	val <- hGetContentsStrict h
+	val <- S.hGetContents h
 	store val repo
 
 {- Stores a git config into a Repo, returning the new version of the Repo.
  - The git config may be multiple lines, or a single line.
  - Config settings can be updated incrementally.
  -}
-store :: String -> Repo -> IO Repo
+store :: S.ByteString -> Repo -> IO Repo
 store s repo = do
 	let c = parse s
 	updateLocation $ repo
@@ -96,7 +100,7 @@ store s repo = do
 
 {- Stores a single config setting in a Repo, returning the new version of
  - the Repo. Config settings can be updated incrementally. -}
-store' :: String -> String -> Repo -> Repo
+store' :: S.ByteString -> S.ByteString -> Repo -> Repo
 store' k v repo = repo
 	{ config = M.singleton k v `M.union` config repo
 	, fullconfig = M.unionWith (++) (M.singleton k [v]) (fullconfig repo)
@@ -127,49 +131,63 @@ updateLocation' r l = do
 		Just d -> do
 			{- core.worktree is relative to the gitdir -}
 			top <- absPath $ gitdir l
-			return $ l { worktree = Just $ absPathFrom top d }
+			let p = absPathFrom top (fromRawFilePath d)
+			return $ l { worktree = Just p }
 	return $ r { location = l' }
 
 {- Parses git config --list or git config --null --list output into a
  - config map. -}
-parse :: String -> M.Map String [String]
-parse [] = M.empty
+parse :: S.ByteString -> M.Map S.ByteString [S.ByteString]
 parse s
-	-- --list output will have an = in the first line
-	| all ('=' `elem`) (take 1 ls) = sep '=' ls
+	| S.null s = M.empty
+	-- --list output will have a '=' in the first line
+	-- (The first line of --null --list output is the name of a key,
+	-- which is assumed to never contain '='.)
+	| S.elem eq firstline = sep eq $ S.split nl s
 	-- --null --list output separates keys from values with newlines
-	| otherwise = sep '\n' $ splitc '\0' s
+	| otherwise = sep nl $ S.split 0 s
   where
-	ls = lines s
-	sep c = M.fromListWith (++) . map (\(k,v) -> (k, [v])) .
-		map (separate (== c))
+	nl = fromIntegral (ord '\n')
+	eq = fromIntegral (ord '=')
+	firstline = S.takeWhile (/= nl) s
+
+	sep c = M.fromListWith (++)
+		. map (\(k,v) -> (k, [S.drop 1 v])) 
+		. map (S.break (== c))
 
 {- Checks if a string from git config is a true value. -}
 isTrue :: String -> Maybe Bool
-isTrue s
+isTrue = isTrue' . encodeBS'
+
+isTrue' :: S.ByteString -> Maybe Bool
+isTrue' s
 	| s' == "true" = Just True
 	| s' == "false" = Just False
 	| otherwise = Nothing
   where
-	s' = map toLower s
+	s' = S8.map toLower s
 
 boolConfig :: Bool -> String
 boolConfig True = "true"
 boolConfig False = "false"
 
-isBare :: Repo -> Bool
-isBare r = fromMaybe False $ isTrue =<< getMaybe coreBare r
+boolConfig' :: Bool -> S.ByteString
+boolConfig' True = "true"
+boolConfig' False = "false"
 
-coreBare :: String
+isBare :: Repo -> Bool
+isBare r = fromMaybe False $ isTrue' =<< getMaybe coreBare r
+
+coreBare :: S.ByteString
 coreBare = "core.bare"
 
 {- Runs a command to get the configuration of a repo,
  - and returns a repo populated with the configuration, as well as the raw
  - output of the command. -}
-fromPipe :: Repo -> String -> [CommandParam] -> IO (Either SomeException (Repo, String))
+fromPipe :: Repo -> String -> [CommandParam] -> IO (Either SomeException (Repo, S.ByteString))
 fromPipe r cmd params = try $
 	withHandle StdoutHandle createProcessSuccess p $ \h -> do
-		val <- hGetContentsStrict h
+		val <- S.hGetContents h
 		r' <- store val r
 		return (r', val)
   where
@@ -177,7 +195,7 @@ fromPipe r cmd params = try $
 
 {- Reads git config from a specified file and returns the repo populated
  - with the configuration. -}
-fromFile :: Repo -> FilePath -> IO (Either SomeException (Repo, String))
+fromFile :: Repo -> FilePath -> IO (Either SomeException (Repo, S.ByteString))
 fromFile r f = fromPipe r "git"
 	[ Param "config"
 	, Param "--file"
@@ -187,13 +205,13 @@ fromFile r f = fromPipe r "git"
 
 {- Changes a git config setting in the specified config file.
  - (Creates the file if it does not already exist.) -}
-changeFile :: FilePath -> String -> String -> IO Bool
+changeFile :: FilePath -> S.ByteString -> S.ByteString -> IO Bool
 changeFile f k v = boolSystem "git"
 	[ Param "config"
 	, Param "--file"
 	, File f
-	, Param k
-	, Param v
+	, Param (decodeBS' k)
+	, Param (decodeBS' v)
 	]
 
 {- Unsets a git config setting, in both the git repo,
@@ -202,10 +220,10 @@ changeFile f k v = boolSystem "git"
  - If unsetting the config fails, including in a read-only repo, or
  - when the config is not set, returns Nothing.
  -}
-unset :: String -> Repo -> IO (Maybe Repo)
+unset :: S.ByteString -> Repo -> IO (Maybe Repo)
 unset k r = ifM (Git.Command.runBool ps r)
 	( return $ Just $ r { config = M.delete k (config r) }
 	, return Nothing
 	)
   where
-	ps = [Param "config", Param "--unset-all", Param k]
+	ps = [Param "config", Param "--unset-all", Param (decodeBS' k)]
diff --git a/Git/ConfigTypes.hs b/Git/ConfigTypes.hs
index 2e262c643a..db5a1285d1 100644
--- a/Git/ConfigTypes.hs
+++ b/Git/ConfigTypes.hs
@@ -5,9 +5,12 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Git.ConfigTypes where
 
 import Data.Char
+import qualified Data.ByteString.Char8 as S8
 
 import Common
 import Git
@@ -18,7 +21,7 @@ data SharedRepository = UnShared | GroupShared | AllShared | UmaskShared Int
 
 getSharedRepository :: Repo -> SharedRepository
 getSharedRepository r =
-	case map toLower $ Git.Config.get "core.sharedrepository" "" r of
+	case S8.map toLower $ Git.Config.get "core.sharedrepository" "" r of
 		"1" -> GroupShared
 		"2" -> AllShared
 		"group" -> GroupShared
@@ -26,14 +29,14 @@ getSharedRepository r =
 		"all" -> AllShared
 		"world" -> AllShared
 		"everybody" -> AllShared
-		v -> maybe UnShared UmaskShared (readish v)
+		v -> maybe UnShared UmaskShared (readish (decodeBS' v))
 
 data DenyCurrentBranch = UpdateInstead | RefusePush | WarnPush | IgnorePush
 	deriving (Eq)
 
 getDenyCurrentBranch :: Repo -> DenyCurrentBranch
 getDenyCurrentBranch r =
-	case map toLower $ Git.Config.get "receive.denycurrentbranch" "" r of
+	case S8.map toLower $ Git.Config.get "receive.denycurrentbranch" "" r of
 		"updateinstead" -> UpdateInstead
 		"warn" -> WarnPush
 		"ignore" -> IgnorePush
diff --git a/Git/Construct.hs b/Git/Construct.hs
index 7191f33036..44ae822e8b 100644
--- a/Git/Construct.hs
+++ b/Git/Construct.hs
@@ -28,6 +28,7 @@ import System.Posix.User
 #endif
 import qualified Data.Map as M
 import Network.URI
+import qualified Data.ByteString as S
 
 import Common
 import Git.Types
@@ -128,7 +129,7 @@ fromRemotes repo = mapM construct remotepairs
 	filterconfig f = filter f $ M.toList $ config repo
 	filterkeys f = filterconfig (\(k,_) -> f k)
 	remotepairs = filterkeys isRemoteKey
-	construct (k,v) = remoteNamedFromKey k $ fromRemoteLocation v repo
+	construct (k,v) = remoteNamedFromKey k (fromRemoteLocation (decodeBS' v) repo)
 
 {- Sets the name of a remote when constructing the Repo to represent it. -}
 remoteNamed :: String -> IO Repo -> IO Repo
@@ -138,7 +139,7 @@ remoteNamed n constructor = do
 
 {- Sets the name of a remote based on the git config key, such as
  - "remote.foo.url". -}
-remoteNamedFromKey :: String -> IO Repo -> IO Repo
+remoteNamedFromKey :: S.ByteString -> IO Repo -> IO Repo
 remoteNamedFromKey = remoteNamed . remoteKeyToRemoteName
 
 {- Constructs a new Repo for one of a Repo's remotes using a given
diff --git a/Git/GCrypt.hs b/Git/GCrypt.hs
index f19b77a98b..94c0b3794a 100644
--- a/Git/GCrypt.hs
+++ b/Git/GCrypt.hs
@@ -7,6 +7,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Git.GCrypt where
 
 import Common
@@ -16,6 +18,8 @@ import qualified Git.Config as Config
 import qualified Git.Command as Command
 import Utility.Gpg
 
+import qualified Data.ByteString as S
+
 urlScheme :: String
 urlScheme = "gcrypt:"
 
@@ -75,9 +79,9 @@ type GCryptId = String
  - which is stored in the repository (in encrypted form)
  - and cached in a per-remote gcrypt-id configuration setting. -}
 remoteRepoId :: Repo -> Maybe RemoteName -> Maybe GCryptId
-remoteRepoId = getRemoteConfig "gcrypt-id"
+remoteRepoId r n = decodeBS' <$> getRemoteConfig "gcrypt-id" r n
 
-getRemoteConfig :: String -> Repo -> Maybe RemoteName -> Maybe String
+getRemoteConfig :: S.ByteString -> Repo -> Maybe RemoteName -> Maybe S.ByteString
 getRemoteConfig field repo remotename = do
 	n <- remotename
 	Config.getMaybe (remoteConfigKey field n) repo
@@ -93,17 +97,17 @@ getParticiantList globalconfigrepo repo remotename = KeyIds $ parse $ firstJust
   where
 	defaultkey = "gcrypt.participants"
 	parse (Just "simple") = []
-	parse (Just l) = words l
+	parse (Just b) = words (decodeBS' b)
 	parse Nothing = []
 
-remoteParticipantConfigKey :: RemoteName -> String
+remoteParticipantConfigKey :: RemoteName -> S.ByteString
 remoteParticipantConfigKey = remoteConfigKey "gcrypt-participants"
 
-remotePublishParticipantConfigKey :: RemoteName -> String
+remotePublishParticipantConfigKey :: RemoteName -> S.ByteString
 remotePublishParticipantConfigKey = remoteConfigKey "gcrypt-publish-participants"
 
-remoteSigningKey :: RemoteName -> String
+remoteSigningKey :: RemoteName -> S.ByteString
 remoteSigningKey = remoteConfigKey "gcrypt-signingkey"
 
-remoteConfigKey :: String -> RemoteName -> String
-remoteConfigKey key remotename = "remote." ++ remotename ++ "." ++ key
+remoteConfigKey :: S.ByteString -> RemoteName -> S.ByteString
+remoteConfigKey key remotename = "remote." <> encodeBS' remotename <> "." <> key
diff --git a/Git/Remote.hs b/Git/Remote.hs
index fa336013e7..7ffaf10fd8 100644
--- a/Git/Remote.hs
+++ b/Git/Remote.hs
@@ -6,6 +6,7 @@
  -}
 
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Git.Remote where
 
@@ -15,18 +16,20 @@ import Git.Types
 
 import Data.Char
 import qualified Data.Map as M
+import qualified Data.ByteString as S
+import qualified Data.ByteString.Char8 as S8
 import Network.URI
 #ifdef mingw32_HOST_OS
 import Git.FilePath
 #endif
 
 {- Is a git config key one that specifies the location of a remote? -}
-isRemoteKey :: String -> Bool
-isRemoteKey k = "remote." `isPrefixOf` k && ".url" `isSuffixOf` k
+isRemoteKey :: S.ByteString -> Bool
+isRemoteKey k = "remote." `S.isPrefixOf` k && ".url" `S.isSuffixOf` k
 
 {- Get a remote's name from the config key that specifies its location. -}
-remoteKeyToRemoteName :: String -> RemoteName
-remoteKeyToRemoteName k = intercalate "." $ dropFromEnd 1 $ drop 1 $ splitc '.' k
+remoteKeyToRemoteName :: S.ByteString -> RemoteName
+remoteKeyToRemoteName = decodeBS' . S.intercalate "." . dropFromEnd 1 . drop 1 . S8.split '.'
 
 {- Construct a legal git remote name out of an arbitrary input string.
  -
@@ -76,16 +79,16 @@ parseRemoteLocation s repo = ret $ calcloc s
 	-- insteadof config can rewrite remote location
 	calcloc l
 		| null insteadofs = l
-		| otherwise = replacement ++ drop (length bestvalue) l
+		| otherwise = replacement ++ drop (S.length bestvalue) l
 	  where
-		replacement = drop (length prefix) $
-			take (length bestkey - length suffix) bestkey
+		replacement = decodeBS' $ S.drop (S.length prefix) $
+			S.take (S.length bestkey - S.length suffix) bestkey
 		(bestkey, bestvalue) = maximumBy longestvalue insteadofs
 		longestvalue (_, a) (_, b) = compare b a
 		insteadofs = filterconfig $ \(k, v) -> 
-			prefix `isPrefixOf` k &&
-			suffix `isSuffixOf` k &&
-			v `isPrefixOf` l
+			prefix `S.isPrefixOf` k &&
+			suffix `S.isSuffixOf` k &&
+			v `S.isPrefixOf` encodeBS l
 		filterconfig f = filter f $
 			concatMap splitconfigs $ M.toList $ fullconfig repo
 		splitconfigs (k, vs) = map (\v -> (k, v)) vs
diff --git a/Git/Types.hs b/Git/Types.hs
index 90401db153..961df6eb52 100644
--- a/Git/Types.hs
+++ b/Git/Types.hs
@@ -35,9 +35,9 @@ data RepoLocation
 
 data Repo = Repo
 	{ location :: RepoLocation
-	, config :: M.Map String String
+	, config :: M.Map S.ByteString S.ByteString
 	-- a given git config key can actually have multiple values
-	, fullconfig :: M.Map String [String]
+	, fullconfig :: M.Map S.ByteString [S.ByteString]
 	-- remoteName holds the name used for this repo in some other
 	-- repo's list of remotes, when this repo is such a remote
 	, remoteName :: Maybe RemoteName
diff --git a/Remote.hs b/Remote.hs
index e54f711acf..363876c29e 100644
--- a/Remote.hs
+++ b/Remote.hs
@@ -147,10 +147,12 @@ byName' n = go . filter matching <$> remoteList
 
 {- Finds the remote or remote group matching the name. -}
 byNameOrGroup :: RemoteName -> Annex [Remote]
-byNameOrGroup n = go =<< getConfigMaybe (ConfigKey ("remotes." ++ n))
+byNameOrGroup n = go =<< getConfigMaybe (ConfigKey ("remotes." <> encodeBS' n))
   where
-	go (Just l) = catMaybes <$> mapM (byName . Just) (splitc ' ' l)
-	go Nothing = maybeToList <$> byName (Just n)
+	go (Just l) = catMaybes
+		<$> mapM (byName . Just) (splitc ' ' (decodeBS' l))
+	go Nothing = maybeToList
+		<$> byName (Just n)
 
 {- Only matches remote name, not UUID -}
 byNameOnly :: RemoteName -> Annex (Maybe Remote)
diff --git a/Remote/GCrypt.hs b/Remote/GCrypt.hs
index ff948ba0d6..931adce3b4 100644
--- a/Remote/GCrypt.hs
+++ b/Remote/GCrypt.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Remote.GCrypt (
 	remote,
 	chainGen,
@@ -16,6 +18,7 @@ module Remote.GCrypt (
 ) where
 
 import qualified Data.Map as M
+import qualified Data.ByteString as S
 import qualified Data.ByteString.Lazy as L
 import Control.Exception
 import Data.Default
@@ -159,11 +162,12 @@ rsyncTransportToObjects r gc = do
 
 rsyncTransport :: Git.Repo -> RemoteGitConfig -> Annex (Annex [CommandParam], String, AccessMethod)
 rsyncTransport r gc
-	| "ssh://" `isPrefixOf` loc = sshtransport $ break (== '/') $ drop (length "ssh://") loc
+	| sshprefix `isPrefixOf` loc = sshtransport $ break (== '/') $ drop (length sshprefix) loc
 	| "//:" `isInfixOf` loc = othertransport
 	| ":" `isInfixOf` loc = sshtransport $ separate (== ':') loc
 	| otherwise = othertransport
   where
+	sshprefix = "ssh://" :: String
 	loc = Git.repoLocation r
 	sshtransport (host, path) = do
 		let rsyncpath = if "/~/" `isPrefixOf` path
@@ -252,7 +256,7 @@ setupRepo gcryptid r
 	| otherwise = localsetup r
   where
 	localsetup r' = do
-		let setconfig k v = liftIO $ Git.Command.run [Param "config", Param k, Param v] r'
+		let setconfig k v = liftIO $ Git.Command.run [Param "config", Param (decodeBS' k), Param v] r'
 		setconfig coreGCryptId gcryptid
 		setconfig denyNonFastForwards (Git.Config.boolConfig False)
 		return AccessDirect
@@ -272,8 +276,8 @@ setupRepo gcryptid r
 			, Param tmpconfig
 			]
 		liftIO $ do
-			void $ Git.Config.changeFile tmpconfig coreGCryptId gcryptid
-			void $ Git.Config.changeFile tmpconfig denyNonFastForwards (Git.Config.boolConfig False)
+			void $ Git.Config.changeFile tmpconfig coreGCryptId (encodeBS' gcryptid)
+			void $ Git.Config.changeFile tmpconfig denyNonFastForwards (Git.Config.boolConfig' False)
 		ok <- liftIO $ rsync $ opts ++
 			[ Param "--recursive"
 			, Param $ tmp ++ "/"
@@ -435,7 +439,7 @@ getGCryptUUID fast r = do
 	(genUUIDInNameSpace gCryptNameSpace <$>) . fst
 		<$> getGCryptId fast r dummycfg
 
-coreGCryptId :: String
+coreGCryptId :: S.ByteString
 coreGCryptId = "core.gcrypt-id"
 
 {- gcrypt repos set up by git-annex as special remotes have a
@@ -457,9 +461,9 @@ getGCryptId fast r gc
 	| otherwise = return (Nothing, r)
   where
 	extract Nothing = (Nothing, r)
-	extract (Just r') = (Git.Config.getMaybe coreGCryptId r', r')
+	extract (Just r') = (decodeBS' <$> Git.Config.getMaybe coreGCryptId r', r')
 
-getConfigViaRsync :: Git.Repo -> RemoteGitConfig -> Annex (Either SomeException (Git.Repo, String))
+getConfigViaRsync :: Git.Repo -> RemoteGitConfig -> Annex (Either SomeException (Git.Repo, S.ByteString))
 getConfigViaRsync r gc = do
 	(rsynctransport, rsyncurl, _) <- rsyncTransport r gc
 	opts <- rsynctransport
diff --git a/Remote/Git.hs b/Remote/Git.hs
index 7aebe8c24f..a04e07cfdd 100644
--- a/Remote/Git.hs
+++ b/Remote/Git.hs
@@ -6,6 +6,7 @@
  -}
 
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Remote.Git (
 	remote,
@@ -68,6 +69,7 @@ import Utility.FileMode
 import Control.Concurrent
 import Control.Concurrent.MSampleVar
 import qualified Data.Map as M
+import qualified Data.ByteString as S
 import Network.URI
 
 remote :: RemoteType
@@ -86,14 +88,14 @@ list autoinit = do
 	rs <- mapM (tweakurl c) =<< Annex.getGitRemotes
 	mapM (configRead autoinit) rs
   where
-	annexurl n = "remote." ++ n ++ ".annexurl"
+	annexurl n = "remote." <> encodeBS' n <> ".annexurl"
 	tweakurl c r = do
 		let n = fromJust $ Git.remoteName r
 		case M.lookup (annexurl n) c of
 			Nothing -> return r
 			Just url -> inRepo $ \g ->
 				Git.Construct.remoteNamed n $
-					Git.Construct.fromRemoteLocation url g
+					Git.Construct.fromRemoteLocation (decodeBS' url) g
 
 {- Git remotes are normally set up using standard git command, not
  - git-annex initremote and enableremote.
@@ -254,7 +256,7 @@ tryGitConfigRead autoinit r
 		v <- liftIO $ Git.Config.fromPipe r cmd params
 		case v of
 			Right (r', val) -> do
-				unless (isUUIDConfigured r' || null val) $ do
+				unless (isUUIDConfigured r' || S.null val) $ do
 					warning $ "Failed to get annex.uuid configuration of repository " ++ Git.repoDescribe r
 					warning $ "Instead, got: " ++ show val
 					warning $ "This is unexpected; please check the network transport!"
diff --git a/Remote/GitLFS.hs b/Remote/GitLFS.hs
index 3da33ac55b..73609026ab 100644
--- a/Remote/GitLFS.hs
+++ b/Remote/GitLFS.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Remote.GitLFS (remote, gen, configKnownUrl) where
 
 import Annex.Common
@@ -153,7 +155,7 @@ mySetup _ mu _ c gc = do
 	-- (so it's also usable by git as a non-special remote),
 	-- and set remote.name.annex-git-lfs = true
 	gitConfigSpecialRemote u c' [("git-lfs", "true")]
-	setConfig (ConfigKey ("remote." ++ getRemoteName c ++ ".url")) url
+	setConfig (ConfigKey ("remote." <> encodeBS' (getRemoteName c) <> ".url")) url
 	return (c', u)
   where
 	url = fromMaybe (giveup "Specify url=") (M.lookup "url" c)
@@ -187,7 +189,7 @@ configKnownUrl r
 	set k v r' = do
 		let ck@(ConfigKey k') = remoteConfig r' k
 		setConfig ck v
-		return $ Git.Config.store' k' v r'
+		return $ Git.Config.store' k' (encodeBS' v) r'
 
 data LFSHandle = LFSHandle
 	{ downloadEndpoint :: Maybe LFS.Endpoint
diff --git a/Remote/Helper/Special.hs b/Remote/Helper/Special.hs
index 510793a8db..7f16ec579d 100644
--- a/Remote/Helper/Special.hs
+++ b/Remote/Helper/Special.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Remote.Helper.Special (
 	findSpecialRemotes,
 	gitConfigSpecialRemote,
@@ -52,6 +54,7 @@ import Messages.Progress
 import qualified Git
 import qualified Git.Construct
 
+import qualified Data.ByteString as S
 import qualified Data.ByteString.Lazy as L
 import qualified Data.Map as M
 
@@ -65,14 +68,15 @@ findSpecialRemotes s = do
 	liftIO $ mapM construct $ remotepairs m
   where
 	remotepairs = M.toList . M.filterWithKey match
-	construct (k,_) = Git.Construct.remoteNamedFromKey k (pure Git.Construct.fromUnknown)
-	match k _ = "remote." `isPrefixOf` k && (".annex-"++s) `isSuffixOf` k
+	construct (k,_) = Git.Construct.remoteNamedFromKey k
+		(pure Git.Construct.fromUnknown)
+	match k _ = "remote." `S.isPrefixOf` k && (".annex-" <> encodeBS' s) `S.isSuffixOf` k
 
 {- Sets up configuration for a special remote in .git/config. -}
 gitConfigSpecialRemote :: UUID -> RemoteConfig -> [(String, String)] -> Annex ()
 gitConfigSpecialRemote u c cfgs = do
 	forM_ cfgs $ \(k, v) -> 
-		setConfig (remoteConfig c k) v
+		setConfig (remoteConfig c (encodeBS' k)) v
 	storeUUIDIn (remoteConfig c "uuid") u
 
 -- RetrievalVerifiableKeysSecure unless overridden by git config.
diff --git a/Test/Framework.hs b/Test/Framework.hs
index ed1aa67d21..187b54ef0e 100644
--- a/Test/Framework.hs
+++ b/Test/Framework.hs
@@ -88,8 +88,8 @@ inmainrepo a = do
 
 with_ssh_origin :: (Assertion -> Assertion) -> (Assertion -> Assertion)
 with_ssh_origin cloner a = cloner $ do
-	origindir <- absPath
-		=<< annexeval (Config.getConfig (Config.ConfigKey config) "/dev/null")
+	origindir <- absPath . decodeBS'
+		=<< annexeval (Config.getConfig (Config.ConfigKey (encodeBS' config)) (toRawFilePath "/dev/null"))
 	let originurl = "localhost:" ++ origindir
 	boolSystem "git" [Param "config", Param config, Param originurl] @? "git config failed"
 	a
diff --git a/Types/Difference.hs b/Types/Difference.hs
index 774336c18e..678b6f4bf6 100644
--- a/Types/Difference.hs
+++ b/Types/Difference.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Types.Difference (
 	Difference(..),
 	Differences(..),
@@ -23,6 +25,7 @@ import qualified Git.Config
 
 import Data.Maybe
 import Data.Monoid
+import qualified Data.ByteString as B
 import qualified Data.Set as S
 import qualified Data.Semigroup as Sem
 import Prelude
@@ -92,11 +95,11 @@ getDifferences :: Git.Repo -> Differences
 getDifferences r = mkDifferences $ S.fromList $
 	mapMaybe getmaybe [minBound .. maxBound]
   where
-	getmaybe d = case Git.Config.isTrue =<< Git.Config.getMaybe (differenceConfigKey d) r of
+	getmaybe d = case Git.Config.isTrue' =<< Git.Config.getMaybe (differenceConfigKey d) r of
 		Just True -> Just d
 		_ -> Nothing
 
-differenceConfigKey :: Difference -> String
+differenceConfigKey :: Difference -> B.ByteString
 differenceConfigKey ObjectHashLower = tunable "objecthashlower"
 differenceConfigKey OneLevelObjectHash = tunable "objecthash1"
 differenceConfigKey OneLevelBranchHash = tunable "branchhash1"
@@ -104,8 +107,8 @@ differenceConfigKey OneLevelBranchHash = tunable "branchhash1"
 differenceConfigVal :: Difference -> String
 differenceConfigVal _ = Git.Config.boolConfig True
 
-tunable :: String -> String
-tunable k = "annex.tune." ++ k
+tunable :: B.ByteString -> B.ByteString
+tunable k = "annex.tune." <> k
 
 hasDifference :: Difference -> Differences -> Bool
 hasDifference _ UnknownDifferences = False
diff --git a/Types/GitConfig.hs b/Types/GitConfig.hs
index 50aa6f2379..ad058171af 100644
--- a/Types/GitConfig.hs
+++ b/Types/GitConfig.hs
@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Types.GitConfig ( 
 	Configurable(..),
 	GitConfig(..),
@@ -199,16 +201,17 @@ extractGitConfig r = GitConfig
 	}
   where
 	getbool k d = fromMaybe d $ getmaybebool k
-	getmaybebool k = Git.Config.isTrue =<< getmaybe k
+	getmaybebool k = Git.Config.isTrue' =<< getmaybe' k
 	getmayberead k = readish =<< getmaybe k
-	getmaybe k = Git.Config.getMaybe k r
-	getlist k = Git.Config.getList k r
+	getmaybe = fmap decodeBS' . getmaybe'
+	getmaybe' k = Git.Config.getMaybe k r
+	getlist k = map decodeBS' $ Git.Config.getList k r
 	getwords k = fromMaybe [] $ words <$> getmaybe k
 
 	configurable d Nothing = DefaultConfig d
 	configurable _ (Just v) = HasConfig v
 
-	annex k = "annex." ++ k
+	annex k = "annex." <> k
 			
 	onemegabyte = 1000000
 
@@ -340,14 +343,15 @@ extractRemoteGitConfig r remotename = do
 		}
   where
 	getbool k d = fromMaybe d $ getmaybebool k
-	getmaybebool k = Git.Config.isTrue =<< getmaybe k
+	getmaybebool k = Git.Config.isTrue' =<< getmaybe' k
 	getmayberead k = readish =<< getmaybe k
-	getmaybe k = mplus (Git.Config.getMaybe (key k) r)
+	getmaybe = fmap decodeBS' . getmaybe'
+	getmaybe' k = mplus (Git.Config.getMaybe (key k) r)
 		(Git.Config.getMaybe (remotekey k) r)
 	getoptions k = fromMaybe [] $ words <$> getmaybe k
 
-	key k = "annex." ++ k
-	remotekey k = "remote." ++ remotename ++ ".annex-" ++ k
+	key k = "annex." <> k
+	remotekey k = "remote." <> encodeBS' remotename <> ".annex-" <> k
 
 notempty :: Maybe String -> Maybe String	
 notempty Nothing = Nothing
diff --git a/Upgrade/V5/Direct.hs b/Upgrade/V5/Direct.hs
index 8b67bb3926..c238101ff3 100644
--- a/Upgrade/V5/Direct.hs
+++ b/Upgrade/V5/Direct.hs
@@ -7,6 +7,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Upgrade.V5.Direct (
 	switchHEADBack,
 	setIndirect,
@@ -49,7 +51,7 @@ setIndirect = do
 		Nothing -> noop
 		Just wt -> do
 			unsetConfig src
-			setConfig dest wt
+			setConfig dest (decodeBS' wt)
 			reloadConfig
 
 {- Converts a directBranch back to the original branch.
diff --git a/doc/todo/optimize_by_converting_String_to_ByteString.mdwn b/doc/todo/optimize_by_converting_String_to_ByteString.mdwn
index 203da76b91..83104bf0dc 100644
--- a/doc/todo/optimize_by_converting_String_to_ByteString.mdwn
+++ b/doc/todo/optimize_by_converting_String_to_ByteString.mdwn
@@ -29,5 +29,3 @@ the `bs` branch has quite a lot of things still needing work, including:
   avoiding a conversion. Note that these are only available on unix, not
   windows, so a compatability shim will be needed.
   (I can't seem to find any library that provides one.)
-
-* Use ByteString for parsing git config to speed up startup.