tree 40fbc20b299c176ca26b7d733bb4d539c99ccd7f
parent 88fb120119b63628a5a4022f796c523ce9c307a9
author benjamin@webkit.org <benjamin@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1415912433 +0000
committer benjamin@webkit.org <benjamin@webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1415912433 +0000

Implement the matching for :nth-last-child(An+B of selector-list)
https://bugs.webkit.org/show_bug.cgi?id=138650

Patch by Benjamin Poulain <bpoulain@apple.com> on 2014-11-13
Reviewed by Andreas Kling.

Source/WebCore:

Matching is trivial based on the existing CSS4 infrastructure.

The tricky part is style invalidation. In the cases of the old :nth-last-child()
and :nth-last-of-type(), we were using the flag ChildrenAffectedByBackwardPositionalRules.

The problem with ChildrenAffectedByBackwardPositionalRules is that it only invalidate
subtrees when nodes are being added or removed. It is a valuable optimization by itself
since tree updates are less common than property updates.

For the case of property updates, I have added the new flag "ChildrenAffectedByPropertyBasedBackwardPositionalRules".
It pretty much work the same way but invalidates subtree on style recalc.

Tests: fast/css/nth-child-and-nth-last-child.html
       fast/css/nth-last-child-of-classname.html
       fast/css/nth-last-child-of-complex-selector.html
       fast/css/nth-last-child-of-compound-selector.html
       fast/css/nth-last-child-of-style-sharing-1.html
       fast/css/nth-last-child-of-style-sharing-2.html
       fast/css/nth-last-child-of-style-update-optimization.html
       fast/css/nth-last-child-of-tagname.html
       fast/selectors/nth-last-child-of-class-style-update.html

* css/SelectorChecker.cpp:
(WebCore::SelectorChecker::checkOne):
* dom/Element.cpp:
(WebCore::Element::setChildrenAffectedByPropertyBasedBackwardPositionalRules):
(WebCore::Element::hasFlagsSetDuringStylingOfChildren):
(WebCore::Element::rareDataChildrenAffectedByPropertyBasedBackwardPositionalRules):
* dom/Element.h:
(WebCore::Element::childrenAffectedByPropertyBasedBackwardPositionalRules):
* dom/ElementRareData.h:
(WebCore::ElementRareData::childrenAffectedByPropertyBasedBackwardPositionalRules):
(WebCore::ElementRareData::setChildrenAffectedByPropertyBasedBackwardPositionalRules):
(WebCore::ElementRareData::ElementRareData):
(WebCore::ElementRareData::resetDynamicRestyleObservations):
* dom/Node.cpp:
(WebCore::Node::updateAncestorsForStyleRecalc):
(WebCore::Node::setNeedsStyleRecalc):
(WebCore::markAncestorsWithChildNeedsStyleRecalc): Deleted.
* dom/Node.h:
Unlike the other marking steps, ChildrenAffectedByPropertyBasedBackwardPositionalRules can only really
affect one level (because we don't have a parent-selectors). It is quite easy to mark large
trees with ChildrenAffectedByPropertyBasedBackwardPositionalRules by using a selector list that is a bit
too generic. When that happen, we must be careful not invalidating everything, just the affected subtree.

LayoutTests:

* fast/selectors/nth-last-child-of-class-style-update-expected.txt: Added.
* fast/selectors/nth-last-child-of-class-style-update.html: Added.
Verify simple cases of style update.

* fast/css/nth-last-child-of-style-update-optimization-expected.txt: Added.
* fast/css/nth-last-child-of-style-update-optimization.html: Added.
Verify that style invalidation stays reasonable.

* fast/css/nth-last-child-of-style-sharing-1-expected.html: Added.
* fast/css/nth-last-child-of-style-sharing-1.html: Added.
* fast/css/nth-last-child-of-style-sharing-2-expected.html: Added.
* fast/css/nth-last-child-of-style-sharing-2.html: Added.
Check that style sharing is disabled for elements matching :nth-last-child().

* fast/css/nth-child-and-nth-last-child-expected.html: Added.
* fast/css/nth-child-and-nth-last-child.html: Added.
Test uniqueness testing by combining :nth-child() and :nth-last-child().

* fast/css/nth-last-child-of-classname-expected.html: Added.
* fast/css/nth-last-child-of-classname.html: Added.
* fast/css/nth-last-child-of-complex-selector-expected.html: Added.
* fast/css/nth-last-child-of-complex-selector.html: Added.
* fast/css/nth-last-child-of-compound-selector-expected.html: Added.
* fast/css/nth-last-child-of-compound-selector.html: Added.
* fast/css/nth-last-child-of-tagname-expected.html: Added.
* fast/css/nth-last-child-of-tagname.html: Added.
Test matching, those are the "last-child" counterpart of the existing
"nth-child-of" tests.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@176084 268f45cc-cd09-0410-ab3c-d52691b4dbfc