stage deletions directly using update-index

no need to run git-rm separately

Git/UpdateIndex.hs

@@ -13,6 +13,7 @@ module Git.UpdateIndex (
 	streamUpdateIndex,
 	lsTree,
 	updateIndexLine,
+	unstageFile,
 	stageSymlink
 ) where
 
@@ -24,6 +25,7 @@ import Git.Types
 import Git.Command
 import Git.FilePath
 import Git.HashObject
+import Git.Sha
 
 {- Streamers are passed a callback and should feed it lines in the form
  - read by update-index, and generated by ls-tree. -}
@@ -61,6 +63,12 @@ updateIndexLine :: Sha -> BlobType -> TopFilePath -> String
 updateIndexLine sha filetype file =
 	show filetype ++ " blob " ++ show sha ++ "\t" ++ getTopFilePath file
 
+{- A streamer that removes a file from the index. -}
+unstageFile :: FilePath -> Repo -> IO Streamer
+unstageFile file repo = do
+	p <- toTopFilePath file repo
+	return $ pureStreamer $ "0 " ++ show nullSha ++ "\t" ++ getTopFilePath p
+
 {- A streamer that adds a symlink to the index. -}
 stageSymlink :: FilePath -> String -> Repo -> IO Streamer
 stageSymlink file linktext repo = do