add support for using hashDirLower in addition to hashDirMixed

Supporting multiple directory hash types will allow converting to a
different one, without a flag day.

gitAnnexLocation now checks which of the possible locations have a file.
This means more statting of files. Several places currently use
gitAnnexLocation and immediately check if the returned file exists;
those need to be optimised.

Command/Add.hs

@@ -60,7 +60,7 @@ undo file key e = do
 		-- fromAnnex could fail if the file ownership is weird
 		tryharder :: IOException -> Annex ()
 		tryharder _ = do
-			src <- fromRepo $ gitAnnexLocation key
+			src <- inRepo $ gitAnnexLocation key
 			liftIO $ moveFile src file
 
 cleanup :: FilePath -> Key -> Bool -> CommandCleanup

Command/Fsck.hs

@@ -87,7 +87,7 @@ verifyLocationLog key desc = do
 	-- Since we're checking that a key's file is present, throw
 	-- in a permission fixup here too.
 	when present $ do
-		f <- fromRepo $ gitAnnexLocation key
+		f <- inRepo $ gitAnnexLocation key
 		liftIO $ do
 			preventWrite f
 			preventWrite (parentDir f)
@@ -118,7 +118,7 @@ verifyLocationLog key desc = do
  - the key's metadata, if available. -}
 checkKeySize :: Key -> Annex Bool
 checkKeySize key = do
-	file <- fromRepo $ gitAnnexLocation key
+	file <- inRepo $ gitAnnexLocation key
 	present <- liftIO $ doesFileExist file
 	case (present, Types.Key.keySize key) of
 		(_, Nothing) -> return True

Command/Migrate.hs

@@ -49,7 +49,7 @@ upgradableKey key = isNothing $ Types.Key.keySize key
  -}
 perform :: FilePath -> Key -> Backend Annex -> CommandPerform
 perform file oldkey newbackend = do
-	src <- fromRepo $ gitAnnexLocation oldkey
+	src <- inRepo $ gitAnnexLocation oldkey
 	tmp <- fromRepo gitAnnexTmpDir
 	let tmpfile = tmp </> takeFileName file
 	cleantmp tmpfile

Command/SendKey.hs

@@ -21,7 +21,7 @@ seek = [withKeys start]
 
 start :: Key -> CommandStart
 start key = do
-	file <- fromRepo $ gitAnnexLocation key
+	file <- inRepo $ gitAnnexLocation key
 	whenM (inAnnex key) $
 		liftIO $ rsyncServerSend file -- does not return
 	warning "requested key is not present"

Command/Unannex.hs

@@ -55,7 +55,7 @@ cleanup file key = do
 	if fast
 		then do
 			-- fast mode: hard link to content in annex
-			src <- fromRepo $ gitAnnexLocation key
+			src <- inRepo $ gitAnnexLocation key
 			liftIO $ do
 				createLink src file
 				allowWrite file

Command/Unlock.hs

@@ -37,7 +37,7 @@ perform dest key = do
 	
 	checkDiskSpace key
 
-	src <- fromRepo $ gitAnnexLocation key
+	src <- inRepo $ gitAnnexLocation key
 	tmpdest <- fromRepo $ gitAnnexTmpLocation key
 	liftIO $ createDirectoryIfMissing True (parentDir tmpdest)
 	showAction "copying"