I knew that wasn't clear. We have a method on the singleton that returns an MOC. If the thread is the main thread, it returns the "main" MOC. If not, it creates a new MOC, and returns that. Then we subsequently pass that MOC around to the various methods responsible for doing the work of creating some objects.
The problem is that passing it around is getting unwieldy. We want to just call the method to get the MOC in multiple places. To do that, we need to store it somewhere appropriate, and TLS was the most appropriate place, except that now I know it's not. The operation is actually not readily available, but won't be too hard to make so. If the NSOperation could've relied on getting a pristine threadDictionary, that would've been very convenient (more specifically, if it could rely on the NSOperation infrastructure to clean up the threadDictionary when the NSOperation finished, it would've been very convenient). On Sep 22, 2010, at 11:43:45, Kyle Sluder wrote: > On Wed, Sep 22, 2010 at 11:31 AM, Rick Mann <rm...@latencyzero.com> wrote: >> Pity. We have a singleton object that creates a subclass of NSOperation, >> which then calls back a method on the singleton that's intended to be run on >> a separate thread (provided indirectly by the NSOperation). That singleton >> needs it's own NSManagedObjectContext, which we were creating and then >> passing around to everything the singleton called. We wanted to avoid the >> danger of creating additional ones by storing it in TLS, but I guess we're >> not supposed to do that (although it does talk about data that you "create >> yourself or manage," which is the case here). > > You wanted to avoid the danger of creating additional > NSManagedObjectContexts? As far as I understand your design, you need > to create a new MOC for every NSOperation instance, regardless of what > thread it winds up being executed on. Theoretically, you'll never even > spawn another thread; you might be running on a Core Solo, and GCD > and/or NSOperationQueue might just run everything on the main thread. > > (I don't know if that's actually possible; GCD operations might always > run on a background thread, but I can certainly foresee the system > deciding not to create more than one background thread on a > single-core Mac.) > > --Kyle Sluder _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
