started converting Ref from String to ByteString

This should make code that reads shas and refs from git faster.

Does not compile yet, a lot needs to be done still.

Git/Command.hs

@@ -81,11 +81,16 @@ pipeReadStrict' reader params repo = assertLocal repo $
 {- Runs a git command, feeding it an input, and returning its output,
  - which is expected to be fairly small, since it's all read into memory
  - strictly. -}
-pipeWriteRead :: [CommandParam] -> Maybe (Handle -> IO ()) -> Repo -> IO String
+pipeWriteRead :: [CommandParam] -> Maybe (Handle -> IO ()) -> Repo -> IO S.ByteString
 pipeWriteRead params writer repo = assertLocal repo $
 	writeReadProcessEnv "git" (toCommand $ gitCommandLine params repo) 
-		(gitEnv repo) writer (Just adjusthandle)
+		(gitEnv repo) writer'
   where
+	writer' = case writer of
+		Nothing -> Nothing
+		Just a -> Just $ \h -> do
+			adjusthandle h
+			a h
 	adjusthandle h = hSetNewlineMode h noNewlineTranslation
 
 {- Runs a git command, feeding it input on a handle with an action. -}

Git/Credential.hs

@@ -58,7 +58,7 @@ urlCredential = Credential . M.singleton "url"
 
 runCredential :: String -> Credential -> Repo -> IO Credential
 runCredential action input r =
-	parseCredential <$> pipeWriteRead 
+	parseCredential . decodeBS <$> pipeWriteRead 
 		[ Param "credential"
 		, Param action
 		]

Git/FilePath.hs

@@ -50,7 +50,7 @@ data BranchFilePath = BranchFilePath Ref TopFilePath
 {- Git uses the branch:file form to refer to a BranchFilePath -}
 descBranchFilePath :: BranchFilePath -> S.ByteString
 descBranchFilePath (BranchFilePath b f) =
-	encodeBS' (fromRef b) <> ":" <> getTopFilePath f
+	fromRef b <> ":" <> getTopFilePath f
 
 {- Path to a TopFilePath, within the provided git repo. -}
 fromTopFilePath :: TopFilePath -> Git.Repo -> RawFilePath

Git/Fsck.hs

@@ -139,7 +139,8 @@ isMissing s r = either (const True) (const False) <$> tryIO dump
 		] r
 
 findShas :: [String] -> [Sha]
-findShas = catMaybes . map extractSha . concat . map words . filter wanted
+findShas = catMaybes . map (extractSha . encodeBS') 
+	. concat . map words . filter wanted
   where
 	wanted l = not ("dangling " `isPrefixOf` l)
 

Git/HashObject.hs

@@ -18,6 +18,7 @@ import qualified Utility.CoProcess as CoProcess
 import Utility.Tmp
 
 import qualified Data.ByteString as S
+import qualified Data.ByteString.Char8 as S8
 import qualified Data.ByteString.Lazy as L
 import Data.ByteString.Builder
 
@@ -39,7 +40,7 @@ hashFile :: HashObjectHandle -> FilePath -> IO Sha
 hashFile h file = CoProcess.query h send receive
   where
 	send to = hPutStrLn to =<< absPath file
-	receive from = getSha "hash-object" $ hGetLine from
+	receive from = getSha "hash-object" $ S8.hGetLine from
 
 class HashableBlob t where
 	hashableBlobToHandle :: Handle -> t -> IO ()

Git/History.hs

@@ -15,6 +15,9 @@ import Git.Command
 import Git.Sha
 
 import qualified Data.Set as S
+import qualified Data.ByteString.Lazy as L
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as B8
 
 data History t = History t (S.Set (History t))
 	deriving (Show, Eq, Ord)
@@ -53,8 +56,9 @@ getHistoryToDepth n commit r = do
 	!h <- fmap (truncateHistoryToDepth n) 
 		. build Nothing 
 		. map parsehistorycommit
-		. lines
-		<$> hGetContents inh
+		. map B.copy
+		. B8.lines
+		<$> L.hGetContents inh
 	hClose inh
 	void $ waitForProcess pid
 	return h
@@ -93,7 +97,7 @@ getHistoryToDepth n commit r = do
 		, Param "--format=%T %H %P"
 		]
 	
-	parsehistorycommit l = case map extractSha (splitc ' ' l) of
+	parsehistorycommit l = case map extractSha (S8.split ' ' l) of
 		(Just t:Just c:ps) -> Just $ 
 			( HistoryCommit
 				{ historyCommit = c

Git/LsFiles.hs

@@ -284,7 +284,7 @@ parseUnmerged s
 				then Nothing
 				else do
 					treeitemtype <- readTreeItemType (encodeBS rawtreeitemtype)
-					sha <- extractSha rawsha
+					sha <- extractSha (encodeBS' rawsha)
 					return $ InternalUnmerged (stage == 2) (toRawFilePath file)
 						(Just treeitemtype) (Just sha)
 		_ -> Nothing

Git/LsTree.hs

@@ -106,6 +106,6 @@ formatLsTree :: TreeItem -> String
 formatLsTree ti = unwords
 	[ showOct (mode ti) ""
 	, decodeBS (typeobj ti)
-	, fromRef (sha ti)
+	, decodeBS' (fromRef (sha ti))
 	, fromRawFilePath (getTopFilePath (file ti))
 	]

Git/Objects.hs

@@ -26,13 +26,13 @@ listPackFiles r = filter (".pack" `isSuffixOf`)
 
 listLooseObjectShas :: Repo -> IO [Sha]
 listLooseObjectShas r = catchDefaultIO [] $
-	mapMaybe (extractSha . concat . reverse . take 2 . reverse . splitDirectories)
+	mapMaybe (extractSha . encodeBS . concat . reverse . take 2 . reverse . splitDirectories)
 		<$> dirContentsRecursiveSkipping (== "pack") True (objectsDir r)
 
 looseObjectFile :: Repo -> Sha -> FilePath
 looseObjectFile r sha = objectsDir r </> prefix </> rest
   where
-	(prefix, rest) = splitAt 2 (fromRef sha)
+	(prefix, rest) = splitAt 2 (decodeBS' (fromRef sha))
 
 listAlternates :: Repo -> IO [FilePath]
 listAlternates r = catchDefaultIO [] (lines <$> readFile alternatesfile)

Git/Ref.hs

@@ -145,8 +145,8 @@ delete :: Sha -> Ref -> Repo -> IO ()
 delete oldvalue ref = run
 	[ Param "update-ref"
 	, Param "-d"
-	, Param $ fromRef ref
-	, Param $ fromRef oldvalue
+	, Param $ decodeBS' (fromRef ref)
+	, Param $ decodeBS' (fromRef oldvalue)
 	]
 
 {- Gets the sha of the tree a ref uses. 
@@ -154,13 +154,17 @@ delete oldvalue ref = run
  - The ref may be something like a branch name, and it could contain
  - ":subdir" if a subtree is wanted. -}
 tree :: Ref -> Repo -> IO (Maybe Sha)
-tree (Ref ref) = extractSha . decodeBS <$$> pipeReadStrict
-	[ Param "rev-parse", Param "--verify", Param "--quiet", Param ref' ]
+tree (Ref ref) = extractSha <$$> pipeReadStrict
+	[ Param "rev-parse"
+	, Param "--verify"
+	, Param "--quiet"
+	, Param (decodeBS' ref')
+	]
   where
-	ref' = if ":" `isInfixOf` ref
+	ref' = if ":" `S.isInfixOf` ref
 		then ref
 		-- de-reference commit objects to the tree
-		else ref ++ ":"
+		else ref <> ":"
 
 {- Checks if a String is a legal git ref name.
  -

Git/RefLog.hs

@@ -12,16 +12,19 @@ import Git
 import Git.Command
 import Git.Sha
 
+import qualified Data.ByteString as S
+import qualified Data.ByteString.Char8 as S8
+
 {- Gets the reflog for a given branch. -}
 get :: Branch -> Repo -> IO [Sha]
 get b = getMulti [b]
 
 {- Gets reflogs for multiple branches. -}
 getMulti :: [Branch] -> Repo -> IO [Sha]
-getMulti bs = get' (map (Param . fromRef) bs)
+getMulti bs = get' (map (Param . decodeBS' . fromRef) bs)
 
 get' :: [CommandParam] -> Repo -> IO [Sha]
-get' ps = mapMaybe extractSha . lines . decodeBS <$$> pipeReadStrict ps'
+get' ps = mapMaybe (extractSha . S.copy) . S8.lines <$$> pipeReadStrict ps'
   where
 	ps' = catMaybes
 		[ Just $ Param "log"

Git/Sha.hs

@@ -5,31 +5,43 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Git.Sha where
 
 import Common
 import Git.Types
 
+import qualified Data.ByteString as S
+import Data.Char
+
 {- Runs an action that causes a git subcommand to emit a Sha, and strips
  - any trailing newline, returning the sha. -}
-getSha :: String -> IO String -> IO Sha
+getSha :: String -> IO S.ByteString -> IO Sha
 getSha subcommand a = maybe bad return =<< extractSha <$> a
   where
 	bad = error $ "failed to read sha from git " ++ subcommand
 
-{- Extracts the Sha from a string. There can be a trailing newline after
- - it, but nothing else. -}
-extractSha :: String -> Maybe Sha
+{- Extracts the Sha from a ByteString. 
+ -
+ - There can be a trailing newline after it, but nothing else.
+ -}
+extractSha :: S.ByteString -> Maybe Sha
 extractSha s
 	| len `elem` shaSizes = val s
-	| len - 1 `elem` shaSizes && length s' == len - 1 = val s'
+	| len - 1 `elem` shaSizes && S.length s' == len - 1 = val s'
 	| otherwise = Nothing
   where
-	len = length s
-	s' = firstLine s
+	len = S.length s
+	s' = firstLine' s
 	val v
-		| all (`elem` "1234567890ABCDEFabcdef") v = Just $ Ref v
+		| S.all validinsha v = Just $ Ref v
 		| otherwise = Nothing
+	validinsha w = or
+		[ w >= 48 && w <= 57 -- 0-9
+		, w >= 97 && w <= 102 -- a-f
+		, w >= 65 && w <= 70 -- A-F
+		]
 
 {- Sizes of git shas. -}
 shaSizes :: [Int]
@@ -41,7 +53,9 @@ shaSizes =
 {- Git plumbing often uses a all 0 sha to represent things like a
  - deleted file. -}
 nullShas :: [Sha]
-nullShas = map (\n -> Ref (replicate n '0')) shaSizes
+nullShas = map (\n -> Ref (S.replicate n zero)) shaSizes
+  where
+	zero = fromIntegral (ord '0')
 
 {- Sha to provide to git plumbing when deleting a file.
  -

Git/Types.hs

@@ -81,10 +81,10 @@ instance IsString ConfigValue where
 type RemoteName = String
 
 {- A git ref. Can be a sha1, or a branch or tag name. -}
-newtype Ref = Ref String
+newtype Ref = Ref S.ByteString
 	deriving (Eq, Ord, Read, Show)
 
-fromRef :: Ref -> String
+fromRef :: Ref -> S.ByteString
 fromRef (Ref s) = s
 
 {- Aliases for Ref. -}

Git/UpdateIndex.hs

@@ -75,14 +75,14 @@ lsTree (Ref x) repo streamer = do
 	mapM_ streamer s
 	void $ cleanup
   where
-	params = map Param ["ls-tree", "-z", "-r", "--full-tree", x]
+	params = map Param ["ls-tree", "-z", "-r", "--full-tree", decodeBS' x]
 lsSubTree :: Ref -> FilePath -> Repo -> Streamer
 lsSubTree (Ref x) p repo streamer = do
 	(s, cleanup) <- pipeNullSplit params repo
 	mapM_ streamer s
 	void $ cleanup
   where
-	params = map Param ["ls-tree", "-z", "-r", "--full-tree", x, p]
+	params = map Param ["ls-tree", "-z", "-r", "--full-tree", decodeBS' x, p]
 
 {- Generates a line suitable to be fed into update-index, to add
  - a given file with a given sha. -}
@@ -90,7 +90,7 @@ updateIndexLine :: Sha -> TreeItemType -> TopFilePath -> L.ByteString
 updateIndexLine sha treeitemtype file = L.fromStrict $
 	fmtTreeItemType treeitemtype
 	<> " blob "
-	<> encodeBS (fromRef sha)
+	<> fromRef sha
 	<> "\t"
 	<> indexPath file
 
@@ -108,7 +108,7 @@ unstageFile file repo = do
 unstageFile' :: TopFilePath -> Streamer
 unstageFile' p = pureStreamer $ L.fromStrict $
 	"0 "
-	<> encodeBS' (fromRef deleteSha)
+	<> fromRef deleteSha
 	<> "\t"
 	<> indexPath p