convert all git read/write functions to use ByteStrings

This yields a second or so speedup in unused, find, etc. Seems that even
when the ByteString is immediately split and then converted to Strings,
it's faster.

I may try to push ByteStrings out into more of git-annex gradually,
although I suspect most of the time-critical parts are already covered
now, and many of the rest rely on libraries that only support Strings.

Git/ByteString.hs

@@ -1,62 +0,0 @@
-{- module using Data.ByteString.Lazy.Char8 for git IO
- -
- - This can be imported instead of Git when more efficient ByteString IO
- - is needed.
- -
- - Copyright 2011 Joey Hess <joey@kitenet.net>
- -
- - Licensed under the GNU GPL version 3 or higher.
- -}
-
-module Git.ByteString (
-	module Git,
-	pipeRead,
-	pipeWrite,
-	pipeWriteRead,
-	pipeNullSplit
-) where
-
-import Control.Applicative
-import System.Cmd.Utils
-import System.IO
-import qualified Data.ByteString.Lazy.Char8 as L
-
-import Git hiding (pipeRead, pipeWrite, pipeWriteRead, pipeNullSplit)
-import Utility.SafeCommand
-
-{- Runs a git subcommand and returns its output, lazily. 
- -
- - Note that this leaves the git process running, and so zombies will
- - result unless reap is called.
- -}
-pipeRead :: Repo -> [CommandParam] -> IO L.ByteString
-pipeRead repo params = assertLocal repo $ do
-	(_, h) <- hPipeFrom "git" $ toCommand $ gitCommandLine repo params
-	hSetBinaryMode h True
-	L.hGetContents h
-
-{- Runs a git subcommand, feeding it input.
- - You should call either getProcessStatus or forceSuccess on the PipeHandle. -}
-pipeWrite :: Repo -> [CommandParam] -> L.ByteString -> IO PipeHandle
-pipeWrite repo params s = assertLocal repo $ do
-	(p, h) <- hPipeTo "git" (toCommand $ gitCommandLine repo params)
-	L.hPut h s
-	hClose h
-	return p
-
-{- Runs a git subcommand, feeding it input, and returning its output.
- - You should call either getProcessStatus or forceSuccess on the PipeHandle. -}
-pipeWriteRead :: Repo -> [CommandParam] -> L.ByteString -> IO (PipeHandle, L.ByteString)
-pipeWriteRead repo params s = assertLocal repo $ do
-	(p, from, to) <- hPipeBoth "git" (toCommand $ gitCommandLine repo params)
-	hSetBinaryMode from True
-	L.hPut to s
-	hClose to
-	c <- L.hGetContents from
-	return (p, c)
-
-{- Reads null terminated output of a git command (as enabled by the -z 
- - parameter), and splits it. -}
-pipeNullSplit :: Repo -> [CommandParam] -> IO [L.ByteString]
-pipeNullSplit repo params = filter (not . L.null) . L.split '\0' <$>
-	pipeRead repo params

Git/LsFiles.hs

@@ -20,13 +20,11 @@ import Utility.SafeCommand
 
 {- Scans for files that are checked into git at the specified locations. -}
 inRepo :: Repo -> [FilePath] -> IO [FilePath]
-inRepo repo l = pipeNullSplit repo $
-	Params "ls-files --cached -z --" : map File l
+inRepo repo l = pipeNullSplit repo $ Params "ls-files --cached -z --" : map File l
 
 {- Scans for files at the specified locations that are not checked into git. -}
 notInRepo :: Repo -> Bool -> [FilePath] -> IO [FilePath]
-notInRepo repo include_ignored l =
-	pipeNullSplit repo $
+notInRepo repo include_ignored l = pipeNullSplit repo $
 		[Params "ls-files --others"] ++ exclude ++
 		[Params "-z --"] ++ map File l
 	where

Git/LsTree.hs

@@ -16,7 +16,7 @@ import Control.Applicative
 import System.Posix.Types
 import qualified Data.ByteString.Lazy.Char8 as L
 
-import Git.ByteString
+import Git
 import Utility.SafeCommand
 
 type Treeish = String
@@ -31,7 +31,7 @@ data TreeItem = TreeItem
 {- Lists the contents of a Treeish -}
 lsTree :: Repo -> Treeish -> IO [TreeItem]
 lsTree repo t = map parseLsTree <$>
-	pipeNullSplit repo [Params "ls-tree --full-tree -z -r --", File t]
+	pipeNullSplitB repo [Params "ls-tree --full-tree -z -r --", File t]
 
 {- Parses a line of ls-tree output.
  - (The --long format is not currently supported.) -}

Git/UnionMerge.hs

@@ -19,7 +19,6 @@ import Data.String.Utils
 import qualified Data.ByteString.Lazy.Char8 as L
 
 import Git
-import qualified Git.ByteString as GitB
 import Utility.SafeCommand
 
 {- Performs a union merge between two branches, staging it in the index.
@@ -44,7 +43,7 @@ merge _ _ = error "wrong number of branches to merge"
 update_index :: Repo -> [String] -> IO ()
 update_index g l = togit ["update-index", "-z", "--index-info"] (join "\0" l)
 	where
-		togit ps content = pipeWrite g (map Param ps) content
+		togit ps content = pipeWrite g (map Param ps) (L.pack content)
 			>>= forceSuccess
 
 {- Generates a line suitable to be fed into update-index, to add
@@ -83,7 +82,7 @@ calc_merge g differ = do
 {- Injects some content into git, returning its hash. -}
 hashObject :: Repo -> L.ByteString -> IO String
 hashObject repo content = getSha subcmd $ do
-	(h, s) <- GitB.pipeWriteRead repo (map Param params) content
+	(h, s) <- pipeWriteRead repo (map Param params) content
 	L.length s `seq` do
 		forceSuccess h
 		reap -- XXX unsure why this is needed
@@ -100,7 +99,7 @@ mergeFile g (info, file) = case filter (/= nullsha) [asha, bsha] of
 	[] -> return Nothing
 	(sha:[]) -> return $ Just $ update_index_line sha file
 	shas -> do
-		content <- GitB.pipeRead g $ map Param ("show":shas)
+		content <- pipeRead g $ map Param ("show":shas)
 		sha <- hashObject g $ unionmerge content
 		return $ Just $ update_index_line sha file
 	where