split BranchChange and lifted

Assistant/Types/BranchChange.hs

@@ -0,0 +1,19 @@
+{- git-annex assistant git-annex branch change tracking
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Assistant.Types.BranchChange where
+
+import Control.Concurrent.MSampleVar
+import Common.Annex
+
+newtype BranchChangeHandle = BranchChangeHandle (MSampleVar ())
+
+newBranchChangeHandle :: IO BranchChangeHandle
+newBranchChangeHandle = BranchChangeHandle <$> newEmptySV
+
+fromBranchChangeHandle :: BranchChangeHandle -> MSampleVar ()
+fromBranchChangeHandle (BranchChangeHandle v) = v