Re: Does initWithHTML:dataUsingEncoding:documentAttributes: run an event loop?
Re: Does initWithHTML:dataUsingEncoding:documentAttributes: run an event loop?
- Subject: Re: Does initWithHTML:dataUsingEncoding:documentAttributes: run an event loop?
- From: Jens Alfke <email@hidden>
- Date: Wed, 08 May 2013 12:14:14 -0700
On May 7, 2013, at 3:52 PM, Ken Thomases <email@hidden> wrote:
> 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.
I’ve had trouble with this method in the past, for exactly that reason — you can get weird reentrancy problems from runloop sources like timers being invoked while in the middle of the call. (It’s also pretty slow.)
IMHO it’s best to avoid this method if you can. For example, the last time this came up all I needed was the plain text, so I wrote a little string transformer to strip out HTML tags and expand HTML entities. For more involved work you could use NSXMLParser (with the “tidy” option) to parse the HTML into a DOM and then walk through that.
—Jens
_______________________________________________
Cocoa-dev mailing list (email@hidden)
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:
This email sent to email@hidden