use subdir for addurl when it creates multiple files

The --file parameter specifies the subdir in this mode.

Command/AddUrl.hs

@@ -60,14 +60,10 @@ seek us = do
 		if Remote.uuid r == webUUID
 			then void $ commandAction $ startWeb relaxed optfile pathdepth u
 			else do
-				let handlecontents url c = case c of
-					UrlContents sz mkf -> 
-						void $ commandAction $
-							startRemote r relaxed optfile pathdepth url sz mkf
-					UrlNested l -> forM_ l $
-						uncurry handlecontents
+				pathmax <- liftIO $ fileNameLengthLimit "."
+				let deffile = fromMaybe (urlString2file u pathdepth pathmax) optfile
 				res <- tryNonAsync $ maybe
-					(error "unable to checkUrl")
+					(error $ "unable to checkUrl of " ++ Remote.name r)
 					(flip id u)
 					(Remote.checkUrl r)
 				case res of
@@ -75,20 +71,19 @@ seek us = do
 						showStart "addurl" u
 						warning (show e)
 						next $ next $ return False
-					Right c -> handlecontents u c
+					Right (UrlContents sz mf) -> do
+						void $ commandAction $
+							startRemote r relaxed (fromMaybe deffile mf) pathdepth u sz
+					Right (UrlMulti l) ->
+						forM_ l $ \(u', sz, f) ->
+							void $ commandAction $
+								startRemote r relaxed (deffile </> f) pathdepth u' sz
 
-startRemote :: Remote -> Bool -> Maybe FilePath -> Maybe Int -> String -> Maybe Integer -> (FilePath -> FilePath) -> CommandStart
-startRemote r relaxed optfile pathdepth s sz mkf = do
-	url <- case Url.parseURIRelaxed s of
-		Nothing -> error $ "bad uri " ++ s
-		Just u -> pure u
-	pathmax <- liftIO $ fileNameLengthLimit "."
-	let file = mkf $ choosefile $ url2file url pathdepth pathmax
+startRemote :: Remote -> Bool -> FilePath -> Maybe Int -> String -> Maybe Integer -> CommandStart
+startRemote r relaxed file pathdepth s sz = do
 	showStart "addurl" file
 	showNote $ "using " ++ Remote.name r 
 	next $ performRemote r relaxed s file sz
-  where
-	choosefile = flip fromMaybe optfile
 
 performRemote :: Remote -> Bool -> URLString -> FilePath -> Maybe Integer -> CommandPerform
 performRemote r relaxed uri file sz = ifAnnexed file adduri geturi
@@ -324,3 +319,8 @@ url2file url pathdepth pathmax = case pathdepth of
 	frombits a = intercalate "/" $ a urlbits
 	urlbits = map (truncateFilePath pathmax . sanitizeFilePath) $
 		filter (not . null) $ split "/" fullurl
+
+urlString2file :: URLString -> Maybe Int -> Int -> FilePath
+urlString2file s pathdepth pathmax = case Url.parseURIRelaxed s of
+	Nothing -> error $ "bad uri " ++ s
+	Just u -> url2file u pathdepth pathmax

Remote/External.hs

@@ -434,10 +434,8 @@ checkurl :: External -> URLString -> Annex UrlContents
 checkurl external url = 
 	handleRequest external (CHECKURL url) Nothing $ \req -> case req of
 		CHECKURL_CONTENTS sz f -> Just $ return $ UrlContents sz
-			(if null f then id else const f)
-		CHECKURL_MULTI l -> Just $ return $ UrlNested $ map mknested l
+			(if null f then Nothing else Just f)
+		CHECKURL_MULTI l -> Just $ return $ UrlMulti l
 		CHECKURL_FAILURE errmsg -> Just $ error errmsg
 		UNSUPPORTED_REQUEST -> error "CHECKURL not implemented by external special remote"
 		_ -> Nothing
-  where
-	mknested (url', sz, f) = (url', UrlContents sz (const f))

Types/UrlContents.hs

@@ -11,9 +11,8 @@ import Utility.Url
 
 data UrlContents
 	-- An URL contains a file, whose size may be known.
-	-- A default filename will be provided, and can be overridded
-	-- or built on.
-	= UrlContents (Maybe Integer) (FilePath -> FilePath)
+	-- There might be a nicer filename to use.
+	= UrlContents (Maybe Integer) (Maybe FilePath)
 	-- Sometimes an URL points to multiple files, each accessible
 	-- by their own URL.
-	| UrlNested [(URLString, UrlContents)]
+	| UrlMulti [(URLString, Maybe Integer, FilePath)]