split out two more Git modules

Git/CheckAttr.hs

@@ -0,0 +1,44 @@
+{- git check-attr interface
+ -
+ - Copyright 2010, 2011 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Git.CheckAttr where
+
+import System.Exit
+
+import Common
+import Git
+import qualified Git.Filename
+
+{- Efficiently looks up a gitattributes value for each file in a list. -}
+lookup :: String -> [FilePath] -> Repo -> IO [(FilePath, String)]
+lookup attr files repo = do
+	-- git check-attr needs relative filenames input; it will choke
+	-- on some absolute filenames. This also means it will output
+	-- all relative filenames.
+	cwd <- getCurrentDirectory
+	let relfiles = map (relPathDirToFile cwd . absPathFrom cwd) files
+	(_, fromh, toh) <- hPipeBoth "git" (toCommand params)
+        _ <- forkProcess $ do
+		hClose fromh
+                hPutStr toh $ join "\0" relfiles
+                hClose toh
+                exitSuccess
+        hClose toh
+	(map topair . lines) <$> hGetContents fromh
+	where
+		params = gitCommandLine 
+				[ Param "check-attr"
+				, Param attr
+				, Params "-z --stdin"
+				] repo
+		topair l = (file, value)
+			where 
+				file = Git.Filename.decode $ join sep $ take end bits
+				value = bits !! end
+				end = length bits - 1
+				bits = split sep l
+				sep = ": " ++ attr ++ ": "