From ab3294f1dd734e7573c859e123158eda8e3551ac Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kitenet.net>
Date: Mon, 1 Nov 2010 18:24:19 -0400
Subject: [PATCH] wrote checkAttr

---
 GitRepo.hs | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/GitRepo.hs b/GitRepo.hs
index 505dd06eb2..e8dd0a5dc3 100644
--- a/GitRepo.hs
+++ b/GitRepo.hs
@@ -35,7 +35,8 @@ module GitRepo (
 	repoRemoteName,
 	inRepo,
 	notInRepo,
-	stagedFiles
+	stagedFiles,
+	checkAttr
 ) where
 
 import Monad (unless)
@@ -145,6 +146,26 @@ attributes repo
 	| bare repo = (workTree repo) ++ "/info/.gitattributes"
 	| otherwise = (workTree repo) ++ "/.gitattributes"
 
+{- Looks up a gitattributes value for each file in a list. -}
+checkAttr :: Repo -> String -> [FilePath] -> IO [(FilePath, String)]
+checkAttr repo attr files = do
+	(pid, fromh, toh) <- hPipeBoth "git" $
+		gitCommandLine repo ["check-attr", attr, "-z", "--stdin"]
+	-- git-check-attr reads all its stdin before outputting anything,
+	-- so we don't need to worry about deadlock
+	hPutStr toh files0
+	hClose toh
+	c <- hGetContentsStrict fromh
+	hClose fromh
+	forceSuccess pid
+	return $ map topair $ lines c
+	where
+		files0 = join "\0" files
+		topair l = (bits !! 0, join sep $ drop 1 $ bits)
+			where 
+				bits = split sep l
+				sep = ": " ++ attr ++ ": "
+
 {- Path to a repository's .git directory, relative to its workTree. -}
 gitDir :: Repo -> String
 gitDir repo