From 6b54817f2688cffc8751b3b1552dca0a34744e61 Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kitenet.net>
Date: Sat, 9 Oct 2010 21:06:46 -0400
Subject: [PATCH] second module!

---
 GitRepo.hs | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 GitRepo.hs

diff --git a/GitRepo.hs b/GitRepo.hs
new file mode 100644
index 0000000000..fece797858
--- /dev/null
+++ b/GitRepo.hs
@@ -0,0 +1,57 @@
+{- git repository handling -}
+
+module GitRepo where
+
+import Directory
+import System.Directory
+import Data.String.Utils
+
+{- Returns the path to the current repository's .git directory.
+ - (For a bare repository, that is the root of the repository.) -}
+gitDir :: IO String
+gitDir = do
+	repo <- repoTop
+	bare <- isBareRepo repo
+	if (bare)
+		then return repo
+		else return $ repo ++ "/.git"
+
+{- Finds the top of the current git repository, which may be in a parent
+ - directory. -}
+repoTop :: IO String
+repoTop = do
+	dir <- getCurrentDirectory
+	top <- seekUp dir isRepoTop
+	case top of
+		(Just dir) -> return dir
+		Nothing -> error "Not in a git repository."
+
+seekUp :: String -> (String -> IO Bool) -> IO (Maybe String)
+seekUp dir want = do
+	ok <- want dir
+	if ok
+		then return (Just dir)
+		else case (parentDir dir) of
+			(Just d) -> seekUp d want
+			Nothing -> return Nothing
+
+parentDir :: String -> Maybe String
+parentDir dir =
+	if length dirs > 0
+	then Just ("/" ++ (join "/" $ take ((length dirs) - 1) dirs))
+	else Nothing
+		where
+			dirs = filter (\x -> length x > 0) $ split "/" dir
+
+isRepoTop dir = do
+	r <- isGitRepo dir
+	b <- isBareRepo dir
+	return (r || b)
+
+isGitRepo dir = gitSignature dir ".git" ".git/config"
+isBareRepo dir = gitSignature dir "objects" "config"
+	
+gitSignature dir subdir file = do
+	s <- (doesDirectoryExist (dir ++ "/" ++ subdir))
+	f <- (doesFileExist (dir ++ "/" ++ file))
+	return (s && f)