tweak

Annex/BranchState.hs

@@ -2,7 +2,7 @@
  -
  - Runtime state about the git-annex branch, including a small read cache.
  -
- - Copyright 2011 Joey Hess <joey@kitenet.net>
+ - Copyright 2011-2012 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -19,31 +19,31 @@ getState = Annex.getState Annex.branchstate
 setState :: BranchState -> Annex ()
 setState state = Annex.changeState $ \s -> s { Annex.branchstate = state }
 
+changeState :: (BranchState -> BranchState) -> Annex ()
+changeState changer = setState =<< changer <$> getState
+
 setCache :: FilePath -> String -> Annex ()
-setCache file content = do
-	state <- getState
-	setState state { cachedFile = Just file, cachedContent = content }
+setCache file content = changeState $ \s -> s
+	{ cachedFile = Just file, cachedContent = content}
 
 getCache :: FilePath -> Annex (Maybe String)
-getCache file = getState >>= go
+getCache file = from <$> getState
 	where
-		go state
+		from state
 			| cachedFile state == Just file =
-				return $ Just $ cachedContent state
-			| otherwise = return Nothing
+				Just $ cachedContent state
+			| otherwise = Nothing
 
 invalidateCache :: Annex ()
-invalidateCache = do
-	state <- getState
-	setState state { cachedFile = Nothing, cachedContent = "" }
+invalidateCache = changeState $ \s -> s
+	{ cachedFile = Nothing, cachedContent = "" }
 
 {- Runs an action to check that the index file exists, if it's not been
  - checked before in this run of git-annex. -}
 checkIndexOnce :: Annex () -> Annex ()
 checkIndexOnce a = unlessM (indexChecked <$> getState) $ do
 	a
-	state <- getState
-	setState state { indexChecked = True }
+	changeState $ \s -> s { indexChecked = True }
 
 {- Runs an action to update the branch, if it's not been updated before
  - in this run of git-annex. -}
@@ -56,6 +56,4 @@ runUpdateOnce a = unlessM (branchUpdated <$> getState) $ do
  - is known to have not changed, or git-annex won't be relying on info
  - from it. -}
 disableUpdate :: Annex ()
-disableUpdate = do
-	state <- getState
-	setState state { branchUpdated = True }
+disableUpdate = changeState $ \s -> s { branchUpdated = True }