> On Jan 14, 2017, at 2:32 PM, Jens Alfke <j...@mooseyard.com> wrote: > > >> On Jan 14, 2017, at 2:41 AM, Daryle Walker <dary...@mac.com >> <mailto:dary...@mac.com>> wrote: >> >> I’m seemingly stuck since the data format doesn’t have a UUID field within >> it and I can’t base a UUID off of a hash of the file since it would change >> after each edit. > > There’s really no way to store any custom metadata in the file? I assume it’s > some sort of database-like file (since it can be used to store CoreData > objects), so couldn’t you create an extra record and store a UUID in it?
No, my file format is straight-up dumb data. I’ve read for years that Core Data can support custom storage formats. Looking into it, I see that there are caveats. My first thought experiment, e-mail messages, was stymied by each non-primitive data block needing to have a database-ish ID. My second thought experiment, mbox files, is now stymied that the file as a whole needs a database-ish ID too. (Since mbox files can be multi-gigabyte, I’d make their loading read-only, letting me use each record’s byte offset as the base for an ID.) These IDs need to be consistently derivable; randomly-generated IDs are no good. If I continue this idea, I’ll stick in a constant UUID and hope Core Data doesn’t really need universally-unique IDs for all potential stores. — Daryle Walker Mac, Internet, and Video Game Junkie darylew AT mac DOT com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
