On 5 Jun 2012, at 14:45, Stephen J. Butler wrote: > On Tue, Jun 5, 2012 at 3:14 AM, Antonio Nunes <devli...@sintraworks.com> > wrote: >> On 5 Jun 2012, at 00:09, Stephen J. Butler wrote: >> >>> You can use extended attributes to attach information to a file. Maybe >>> serialize your session state as a plist and use setxattr/getxattr to >>> manipulate it. Follows the file as it's moved around. >> >> Thanks Stephen, >> >> I think the extended attributes are pretty persistent though, they'll follow >> the file around across to other computers, right? I wouldn't want that. I >> only need the data on the particular user's system. Starting to look like >> l'm probably better off devising my own scheme. > > In general, yes. It won't follow if you upload to a website, say > Dropbox, and then someone else downloads it. But if you copy it to a > thumb drive and send it then it will. > > One thing you could try is to mix the two ideas. Generate a GUID for > each file and store that in the extended attribute. Then use the GUID > to lookup your session information in an application CoreData store or > simple SQLite database. > > Then only the GUID follows the file around, and on another machine it > won't have the session information and you can create it fresh. Also, > you'll have to handle the case when a file doesn't have a GUID in its > extended attributes and attach a new one.
Thanks Stephen, I think that would be a bit overkill for my purposes though, since I really only want this info on the original machine. Also, Jens noted a possible issue with multiple copies of the same document. What I ended up doing is something not totally unlike what Graham suggested: I create a url bookmark that contains a UUID in the name on disk. Next to it I save the data required when reopening the file, with the same UUID incorporated in the name. The when a file is opened, I test the cached bookmarks for a match with the current document. If a match is found, then the UUID leads me to the restoration data, which is then loaded and used. Using bookmarks, rather than static URLs (as I think Graham does) has the benefit that it should be more robust when the file gets moved around between sessions: When reopening the file from another directory, the bookmark URL resolves to the new location, which is exactly what is needed. -António ---------------------------------------------------- Energy is like a muscle, it grows stronger through being used. ---------------------------------------------------- _______________________________________________ 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
