Check file for being used by some other process when using Flat File Source

I am wondering how easy is to check for file locks and have our SSIS Package to wait until file has been release by the process which is using it.

Also, same question when we're writing to a Flat File (or Flat File Destination).

Thanks,I think best way is to use script task, in while loop check for file info, if it is locked continue if not then break or set some variable stating that file is unlocked now.