Right. I dispatch the block on the main thread to solve the reentrancy issues as stated below. The serial queue is involved elsewhere.
On 15 mai 2013, at 16:12, Ken Thomases wrote: > On May 15, 2013, at 8:58 AM, Jean Suisse wrote: > >> Thanks for your replies. >> Unfortunately, I can't easily avoid >> initWithHTML:dataUsingEncoding:documentAttributes: >> But I can postpone it long enough to move its execution to an other thread >> (serial dispatch queue). >> That solves the issue. > > I doubt it will. If that method is invoked from a background thread, it will > shunt the work to the main thread anyway. In other words, it always does its > work on the main thread. > > Regards, > Ken > On 8 may 2013, at 01:06, Jean Suisse wrote: > Thanks for this suggestion. Actually, once identified, I fixed the bug fairly > quickly by postponing the task (dispatched a block on the main thread for > that). > The bug was caused by two successive events arriving in a short timeframe so > that the stack looked like that: > > 0 my callback > 1 __CFSocketPerformV0 > ------------------------------------ > 9 initWithHTML:dataUsingEncoding:documentAttributes: > 10 my function 1 > 11 my function 2 > 12 my callback > 13 __CFSocketPerformV0 > ----------------------------------- > 23 NSApplicationMain > 24 main > 25 Start > > and my callback never was designed to be called a second time before the > first call was finished. Dispatching a block to handle my function 1 fixed > the issue. > However, information about initWithHTML:dataUsingEncoding:documentAttributes: > running an event loop could be worth mentioning in the docs… > > Jean > > On 8 mai 2013, at 00:52, Ken Thomases wrote: > >> On May 7, 2013, at 5:37 PM, Jean Suisse wrote: >> >>> By any chance, could a call to [[NSAttributedString alloc] >>> initWithHTML:dataUsingEncoding:documentAttributes:] lead to the event loop >>> being run before the call returns? >> >> Yes, it can. Under the hood, NSAttributedString is using WebKit for HTML >> rendering. In part that means that, when invoked from a background thread, >> it has to shunt the work to the main thread. But it also means the main >> thread may have to run the run loop during the call. It's a nuisance, but >> it's necessary since HTML can have references to external resources that >> need to be loaded. >> >> Consider the other method, -[NSAttributedString >> initWithHTML:options:documentAttributes:] and its options dictionary, which >> can have keys like NSTimeoutDocumentOption and >> NSWebResourceLoadDelegateDocumentOption. Those imply a pretty involved >> process under the hood. I'm fairly certain that this method is used for the >> implementation of the method you're using. >> >> You may be able to use those options to minimize the use of the run loop, >> but probably not eliminate it. >> >> Regards, >> Ken >> > > ----------- > Jean Suisse > Institut de Chimie Moléculaire de l’Université de Bourgogne > (ICMUB) — UMR 6302 > _______________________________________________ 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
