Bug 16780 – CSSSelector doesn't use subclassing, contains fields for all types of selectors

• Status: RESOLVED
• Resolution: WONTFIX
• Component: CSS

[Eric Seidel (no email)]

CSSSelector is a memory hog

Wow.  We don't have any subclasses of CSSSelector?  Makes little sense to me.  It seems that breaking things like "QualifiedName attr" off into a less-used CSSSelector subclass could be a Very Large™ memory savings for WebCore, given how large modern CSS files can be.  This could be a win for mobile devices which have tighter memory constraints.

[Maciej Stachowiak]

I don't think CSSStyleSelector creates that much memory use in practice, so I'm not sure this would have a huge memory impact. But using subclasses may result in cleaner code. Hard to say.

[Eric Seidel (no email)]

I'm confused as to if you mean CSSStyleSelector or CSSSelector in your comment.  I mean the latter.  CSSStyleSelector contributes very little to memory usage (there is only one per doc).  There is one CSSSelector object per selector in a CSS document.  I've not tested to confirm the memory usage, but it's certainly non-zero.

[Maciej Stachowiak]

I meant CSSSelector. Damn those confusingly similar names!

[Dave Hyatt]

Yeah, this could be optimized some.  It's never been that big a deal, since there just aren't that many selectors per document.  In general the stylesheets themselves don't take up that much memory relative to other things.

[Benjamin Poulain]

Closing: CSSSelector takes very little memory.