934788 - Faster selector matching for attribute selectors by not counting the number of attributes

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Olli Pettay [:smaug][[e-mail]]]

Attachment: patch

Currently SelectorMatches uses GetAttrCount and (safe) GetAttrNameAt to iterate
over all the attributes. Use of the latter should be enough, and we can add
a fast HasAttrs to Element.

We may want to add a faster way to get attr count, but it just shouldn't be
needed at all here.

Seems to help a % or two with bug 917247.

(Other things we could perhaps fix is GetAttr usage and string copying/addrefing,
few % could be optimized there)

https://tbpl.mozilla.org/?tree=Try&rev=6abee7f8a9d1

Comment 1

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 827140 [details] [diff] [review]
patch

>+    return MappedAttrCount() || (AttrSlotCount() && mImpl->mBuffer[0]);

I'd prefer AttrSlotIsTaken(0) for that last check; it's clearer as to what's really going on and why it's safe.

r=me with that

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Attachment: patch

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/d1ea27ce8789

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/d1ea27ce8789