On Tuesday 2012-10-09 17:06 -0700, Seth Fowler wrote: > > I'm assuming that you're talking about nsStyleContext lazily > > computing the results of GetStyle*() when those functions are called > > rather than computing it at the time the style context is created > > (which is itself buffered up in ways that are very important). > > Indeed. > > > Off the top of my head, I think the biggest reason for this is that > > it's probably a bit of a savings in memory use, since there are a > > bunch of structs that we won't create for many elements -- though as > > bz said, I'm not sure how true that is anymore. > > That makes perfect sense, but what isn't immediately clear to me is whether > there are any cases where an eager CSS implementation couldn't determine > in advance that a given style struct wouldn't be needed. If so, laziness is > just > an implementation strategy for this optimization and not a requirement.
We can never determine for sure that a given struct will never need a struct, since a page can always ask for a style in it via getComputedStyle (except for the rare style context that couldn't potentially be used from a getComputedStyle call). So I don't see how we can keep the space optimization without also keeping the ability to compute lazily. That said, some of the advantages of computing eagerly might remain. -David -- 𝄞 L. David Baron http://dbaron.org/ 𝄂 𝄢 Mozilla http://www.mozilla.org/ 𝄂 _______________________________________________ dev-tech-layout mailing list [email protected] https://lists.mozilla.org/listinfo/dev-tech-layout
