avoid double work in git-annex init

reconcileStaged was doing a redundant scan to scannAnnexedFiles.

It would probably make sense to move the body of scannAnnexedFiles
into reconcileStaged, the separation does not really serve any purpose.

Sponsored-by: Dartmouth College's Datalad project

Database/Keys.hs

@@ -23,6 +23,7 @@ module Database.Keys (
 	removeInodeCache,
 	isInodeKnown,
 	runWriter,
+	runWriter',
 ) where
 
 import qualified Database.Keys.SQL as SQL
@@ -73,7 +74,7 @@ runReader a = do
 		v <- a (SQL.ReadHandle qh)
 		return (v, st)
 	go DbClosed = do
-		st' <- openDb True DbClosed
+		st' <- openDb True Nothing DbClosed
 		v <- case st' of
 			(DbOpen qh) -> a (SQL.ReadHandle qh)
 			_ -> return mempty
@@ -87,7 +88,15 @@ runReaderIO a = runReader (liftIO . a)
  -
  - The database is created if it doesn't exist yet. -}
 runWriter :: (SQL.WriteHandle -> Annex ()) -> Annex ()
-runWriter a = do
+runWriter = runWriter' Nothing
+
+runWriterIO :: (SQL.WriteHandle -> IO ()) -> Annex ()
+runWriterIO a = runWriter (liftIO . a)
+
+{- When a reconcile action is passed, it is run by reconcileStaged instead
+ - of its usual scan, and must update the database in the same way. -}
+runWriter' :: Maybe (SQL.WriteHandle -> Annex ()) -> (SQL.WriteHandle -> Annex ()) -> Annex ()
+runWriter' reconciler a = do
 	h <- Annex.getRead Annex.keysdbhandle
 	withDbState h go
   where
@@ -95,15 +104,12 @@ runWriter a = do
 		v <- a (SQL.WriteHandle qh)
 		return (v, st)
 	go st = do
-		st' <- openDb False st
+		st' <- openDb False reconciler st
 		v <- case st' of
 			DbOpen qh -> a (SQL.WriteHandle qh)
 			_ -> error "internal"
 		return (v, st')
 
-runWriterIO :: (SQL.WriteHandle -> IO ()) -> Annex ()
-runWriterIO a = runWriter (liftIO . a)
-
 {- Opens the database, creating it if it doesn't exist yet.
  -
  - Multiple readers and writers can have the database open at the same
@@ -112,10 +118,10 @@ runWriterIO a = runWriter (liftIO . a)
  - the database doesn't exist yet, one caller wins the lock and
  - can create it undisturbed.
  -}
-openDb :: Bool -> DbState -> Annex DbState
-openDb _ st@(DbOpen _) = return st
-openDb False DbUnavailable = return DbUnavailable
-openDb forwrite _ = catchPermissionDenied permerr $ withExclusiveLock gitAnnexKeysDbLock $ do
+openDb :: Bool -> (Maybe (SQL.WriteHandle -> Annex ())) -> DbState -> Annex DbState
+openDb _ _ st@(DbOpen _) = return st
+openDb False _ DbUnavailable = return DbUnavailable
+openDb forwrite reconciler _ = catchPermissionDenied permerr $ withExclusiveLock gitAnnexKeysDbLock $ do
 	dbdir <- fromRepo gitAnnexKeysDb
 	let db = dbdir P.</> "db"
 	dbexists <- liftIO $ R.doesPathExist db
@@ -133,7 +139,7 @@ openDb forwrite _ = catchPermissionDenied permerr $ withExclusiveLock gitAnnexKe
 	
 	open db = do
 		qh <- liftIO $ H.openDbQueue H.MultiWriter db SQL.containedTable
-		reconcileStaged qh
+		reconcileStaged qh reconciler
 		return $ DbOpen qh
 
 {- Closes the database if it was open. Any writes will be flushed to it.
@@ -223,8 +229,8 @@ isInodeKnown i s = or <$> runReaderIO ((:[]) <$$> SQL.isInodeKnown i s)
  - So when using getAssociatedFiles, have to make sure the file still
  - is an associated file.
  -}
-reconcileStaged :: H.DbQueue -> Annex ()
-reconcileStaged qh = do
+reconcileStaged :: H.DbQueue -> Maybe (SQL.WriteHandle -> Annex ()) -> Annex ()
+reconcileStaged qh mreconciler = do
 	gitindex <- inRepo currentIndexFile
 	indexcache <- fromRawFilePath <$> fromRepo gitAnnexKeysDbIndexCache
 	withTSDelta (liftIO . genInodeCache gitindex) >>= \case
@@ -246,12 +252,21 @@ reconcileStaged qh = do
 	go cur indexcache (Just newtree) = do
 		oldtree <- getoldtree
 		when (oldtree /= newtree) $ do
+			case mreconciler of
+				Just reconciler ->
+					reconciler (SQL.WriteHandle qh)
+				Nothing -> noop
 			g <- Annex.gitRepo
-			void $ catstream $ \mdfeeder -> 
-				void $ updatetodiff g
-					(Just (fromRef oldtree)) 
-					(fromRef newtree)
-					(procdiff mdfeeder)
+			void $ catstream $ \mdfeeder -> do
+				case mreconciler of
+					Nothing -> void $ updatetodiff g
+						(Just (fromRef oldtree)) 
+						(fromRef newtree)
+						(procdiff mdfeeder)
+					Just _ -> void $ updatetodiff g
+						Nothing "--staged"
+						(procdiff mdfeeder)
+
 			liftIO $ writeFile indexcache $ showInodeCache cur
 			-- Storing the tree in a ref makes sure it does not
 			-- get garbage collected, and is available to diff