Hi,
Current code re-checks file existence always in same order, so worst case is - N files and only last of them does not exists. In that case this code will re-check (N-1) files during each consecutive retry. This can be optimized by moving already existing files to the end of file list(or dropping them from list completely, if files are only > > added but never removed). For this you could re-write `allFilesThere` something like: allFilesThere fs = liftIO $ do existing, non_existing <- partitionM (doesFileExist . fromAbsFile) fs < return (non_existing++ existing, null non_existing)
Then allFilesThere could start next iteration by checking previously non-existing files and probably failing much faster.
thanks a lot, files are never removed, so I can forget already checked files :)