wip RawFilePath

Goal is to make git-annex faster by using ByteString for all the
worktree traversal. For now, this is focusing on Command.Find,
in order to benchmark how much it helps. (All other commands are
temporarily disabled)

Currently in a very bad unbuildable in-between state.

Git/LsTree.hs

@@ -26,12 +26,16 @@ import Git.FilePath
 import qualified Git.Filename
 
 import Numeric
-import Data.Char
+import Data.Either
 import System.Posix.Types
+import qualified Data.ByteString as S
+import qualified Data.ByteString.Lazy as L
+import qualified Data.Attoparsec.ByteString.Lazy as A
+import qualified Data.Attoparsec.ByteString.Char8 as A8
 
 data TreeItem = TreeItem
 	{ mode :: FileMode
-	, typeobj :: String
+	, typeobj :: S.ByteString
 	, sha :: Ref
 	, file :: TopFilePath
 	} deriving Show
@@ -45,7 +49,7 @@ lsTree = lsTree' []
 lsTree' :: [CommandParam] -> LsTreeMode -> Ref -> Repo -> IO ([TreeItem], IO Bool)
 lsTree' ps lsmode t repo = do
 	(l, cleanup) <- pipeNullSplit (lsTreeParams lsmode t ps) repo
-	return (map parseLsTree l, cleanup)
+	return (rights (map parseLsTree l), cleanup)
 
 lsTreeParams :: LsTreeMode -> Ref -> [CommandParam] -> [CommandParam]
 lsTreeParams lsmode r ps =
@@ -63,7 +67,8 @@ lsTreeParams lsmode r ps =
 
 {- Lists specified files in a tree. -}
 lsTreeFiles :: Ref -> [FilePath] -> Repo -> IO [TreeItem]
-lsTreeFiles t fs repo = map parseLsTree <$> pipeNullSplitStrict ps repo
+lsTreeFiles t fs repo = rights . map (parseLsTree . L.fromStrict)
+	<$> pipeNullSplitStrict ps repo
   where
 	ps =
 		[ Param "ls-tree"
@@ -73,30 +78,34 @@ lsTreeFiles t fs repo = map parseLsTree <$> pipeNullSplitStrict ps repo
 		, File $ fromRef t
 		] ++ map File fs
 
+parseLsTree :: L.ByteString -> Either String TreeItem
+parseLsTree b = case A.parse parserLsTree b of
+	A.Done _ r  -> Right r
+	A.Fail _ _ err -> Left err
+
 {- Parses a line of ls-tree output, in format:
  - mode SP type SP sha TAB file
  -
  - (The --long format is not currently supported.) -}
-parseLsTree :: String -> TreeItem
-parseLsTree l = TreeItem 
-	{ mode = smode
-	, typeobj = t
-	, sha = Ref s
-	, file = sfile
-	}
-  where
-	(m, past_m) = splitAt 7 l -- mode is 6 bytes
-	(!t, past_t) = separate isSpace past_m
-	(!s, past_s) = splitAt shaSize past_t
-	!f = drop 1 past_s
-	!smode = fst $ Prelude.head $ readOct m
-	!sfile = asTopFilePath $ Git.Filename.decode f
+parserLsTree :: A.Parser TreeItem
+parserLsTree = TreeItem
+	-- mode
+	<$> A8.decimal
+	<* A8.char ' '
+	-- type
+	<*> A.takeTill (== 32)
+	<* A8.char ' '
+	-- sha
+	<*> (Ref . decodeBS' <$> A.take shaSize)
+	<* A8.char '\t'
+	-- file
+	<*> (asTopFilePath . decodeBS' . Git.Filename.decode <$> A.takeByteString)
 
 {- Inverse of parseLsTree -}
 formatLsTree :: TreeItem -> String
 formatLsTree ti = unwords
 	[ showOct (mode ti) ""
-	, typeobj ti
+	, decodeBS (typeobj ti)
 	, fromRef (sha ti)
 	, getTopFilePath (file ti)
 	]