71261 - Add support for :-moz-bound-element matching the bound element in scoped stylesheets

Status: RESOLVED FIXED

(Core :: XBL, defect)

Description

[David Hyatt]

If XBL-scoped stylesheets could use a pseudoclass to refer to the bound element,
then stylesheets could be written that could apply to any tag, thus allowing us
to reuse the same stylesheets for both XBL-based HTML form controls and
XBL-based XUL widgets.

Comment 1

[David Hyatt]

As requested, cc'ing pierre for review.  This patch enhances the scoped
stylesheet support a bit and involves a minimal patch to the style system.  I
don't think it will conflict with your style context work, so I'm submitting it
for review now.

Comment 2

[David Hyatt]

Attachment: The patch.

Comment 3

[David Hyatt]

Looking for sr from either attinasi or brendan.  

Comment 4

[Marc Attinasi]

I am worried about the extra work being done in the SelectorMatchesData
constructor - can we cache the styleset and pass it into the SelectorMatchesData
ctor instead of having to get it from the presContent->presShell? The
StyleContext also has a reference to the style set, although it is currently not
exposed. Building SelectorMatchesData instances has to be as fast as possible!

Also, should the additions to the SelectorMatchesData class be #ifdef'd? Do we
want to carry around the mStyleRuleSupplier if no XUL is being compiled in?

Comment 5

[David Hyatt]

This is XBL, not XUL,so no #ifdefs.  This is for HTML as well.  (In fact all my
tests are HTML.)  I'll see what I can do about passing the styleset in.

Comment 6

[David Hyatt]

I don't believe this patch would cause any kind of slowdown.  It only has to
fill in two pointers (with two addrefs) to get to the styleset from the pres
context.  

Easiest thing to do is to back this up with some numbers, so I'll run jrgm's
tests and let you know the results.

Comment 7

[David Hyatt]

Ok, I have a clever solution.  The selector matches data lazily initializes the
style rule supplier member variable.  This way, you only obtain the style rule
supplier if/when you encounter the :-moz-bound-element pseudo.  

Patch forthcoming.

Comment 8

[David Hyatt]

Attachment: Patch #2 to nsCSSStyleSheet.cpp (the rest is the same)

Comment 9

[David Hyatt]

Ready for another r/sr.

Comment 10

[Marc Attinasi]

Very nice, David. And sorry to confuse the XUL #ifdef ;)

sr=attinasi pending Pierre's r=

Comment 11

[David Hyatt]

Fixed.