Load SVG (and other) UA StyleSheets dynamically when needed

• Component: CSS
• Status: RESOLVED FIXED

[Eric Seidel (no email)]

Load SVG (and other) UA StyleSheets dynamically when needed

Hyatt would like to see a solution like this land before landing MathML support.

[Rob Buis]

Created attachment 17645 [details]
First attempt

This patch implements the lazy loading of the svg sheet. I think it is the only UA sheet yet which can be treated that way. Note that the const MediaQueryEvaluator
stuff is not essential, just seems clearer to me.
Cheers,

Rob.

[Darin Adler]

Comment on attachment 17645 [details]
First attempt

+static const MediaQueryEvaluator screenEval("screen");
+static const MediaQueryEvaluator printEval("print");

We can't have global objects with constructors like these in WebKit -- causes a performance problem, especially on Mac OS X. You can instead put create functions that return the objects.

+#if ENABLE(SVG)
+    if (e->isSVGElement() && !svgSheet) {
+        // SVG rules.
+        svgSheet = parseUASheet(svgUserAgentStyleSheet);
+        defaultStyle->addRulesFromSheet(svgSheet, &screenEval);
+        defaultPrintStyle->addRulesFromSheet(svgSheet, &printEval);
+    }
+#endif
     int firstUARule = -1, lastUARule = -1;

I think you need a blank line after the #endif

review- because of the global initializers

[Rob Buis]

Created attachment 17652 [details]
Fixing the global ctor problem

This should fix the global ctor efficiency problem.
Cheers,

Rob.

[Darin Adler]

Comment on attachment 17652 [details]
Fixing the global ctor problem

How does this fix the global constructor problem? I don't see any change in that part of the patch. Maybe you accidentally re-posted the same patch?

[Rob Buis]

Hi Darin,

(In reply to comment #4)
> (From update of attachment 17652 [details] [edit])
> How does this fix the global constructor problem? I don't see any change in
> that part of the patch. Maybe you accidentally re-posted the same patch?

Oops, you are right :( Will put up the one I intended.
Cheers,

Rob.

[Rob Buis]

Created attachment 17653 [details]
Really fix the global ctor problem

This is the patch I meant to address Darins issues with my first attempt, ignore the previous attachment.
Cheers,

Rob.

[Darin Adler]

Comment on attachment 17653 [details]
Really fix the global ctor problem

Looks fine, but I'm not happy with the trailing underscore naming scheme. In the past we've used the word static, like:

     static const MediaQueryEvaluator staticPrintEval("print");

Looks good. r=me

[Rob Buis]

Landed in r28321.