use openTempFile from file-io

And follow-on changes.

Note that relatedTemplate was changed to operate on a RawFilePath, and
so when it counts the length, it is now the number of bytes, not the
number of code points. This will just make it truncate shorter strings
in some cases, the truncation is still unicode aware.

When not building with the OsPath flag, toOsPath . fromRawFilePath and
fromRawFilePath . fromOsPath do extra conversions back and forth between
String and ByteString. That overhead could be avoided, but that's the
non-optimised build mode, so didn't bother.

Sponsored-by: unqueued

Command/Multicast.hs

@@ -130,7 +130,7 @@ send ups fs = do
 	-- the names of keys, and would have to be copied, which is too
 	-- expensive.
 	starting "sending files" (ActionItemOther Nothing) (SeekInput []) $
-		withTmpFile "send" $ \t h -> do
+		withTmpFile (toOsPath "send") $ \t h -> do
 			let ww = WarnUnmatchLsFiles "multicast"
 			(fs', cleanup) <- seekHelper id ww LsFiles.inRepo
 				=<< workTreeItems ww fs
@@ -163,7 +163,7 @@ send ups fs = do
 					-- only allow clients on the authlist
 					, Param "-H", Param ("@"++authlist)
 					-- pass in list of files to send
-					, Param "-i", File t
+					, Param "-i", File (fromRawFilePath (fromOsPath t))
 					] ++ ups
 				liftIO (boolSystem "uftp" ps) >>= showEndResult
 			next $ return True
@@ -178,7 +178,7 @@ receive ups = starting "receiving multicast files" ai si $ do
 	(callback, environ, statush) <- liftIO multicastCallbackEnv
 	tmpobjdir <- fromRepo gitAnnexTmpObjectDir
 	createAnnexDirectory tmpobjdir
-	withTmpDirIn (fromRawFilePath tmpobjdir) "multicast" $ \tmpdir -> withAuthList $ \authlist -> do
+	withTmpDirIn (fromRawFilePath tmpobjdir) (toOsPath "multicast") $ \tmpdir -> withAuthList $ \authlist -> do
 		abstmpdir <- liftIO $ absPath (toRawFilePath tmpdir)
 		abscallback <- liftIO $ searchPath callback
 		let ps =
@@ -245,10 +245,10 @@ uftpUID u = "0x" ++ (take 8 $ show $ sha2_256 $ B8.fromString (fromUUID u))
 withAuthList :: (FilePath -> Annex a) -> Annex a
 withAuthList a = do
 	m <- knownFingerPrints
-	withTmpFile "authlist" $ \t h -> do
+	withTmpFile (toOsPath "authlist") $ \t h -> do
 		liftIO $ hPutStr h (genAuthList m)
 		liftIO $ hClose h
-		a t
+		a (fromRawFilePath (fromOsPath t))
 
 genAuthList :: M.Map UUID Fingerprint -> String
 genAuthList = unlines . map fmt . M.toList