Fix for bug 13337, deep tag nesting is slow. This patch fixes a number of O(n^2) issues as well as making
a few performance optimizations based off profiling. Details next to each change below.
Note that calcMinMaxWidth being slow is a critical separate piece of this puzzle. Until bug 13430 is fixed,
render tree construction will be O(n^2) (because of the minmaxrecalc bit setting being stupid enough to
always crawl to the root of the tree) and calcMinMaxWidth will waste tons of unnecessary time.
When these fixes are combined with the calcMinMaxWidth fix in 13430, the penguin page specified in 13337
loads in < 2 seconds (down from an infinite hang before).
Reviewed by aroben, ollie
* css/cssstyleselector.cpp:
(WebCore::CSSStyleSelector::locateCousinList):
(WebCore::CSSStyleSelector::locateSharedStyle):
* css/csstyleselector.h
Cap the depth of cousin searching on the shared style optimization. We will be willing to (at most) crawl
up the tree the same distance that we were willing to crawl backwards through sibling lists. Leaving it
uncapped resulted in pathological style resolution for the case of an infinitely nested chain of singletons.
* html/HTMLParser.cpp:
(WebCore::HTMLParser::handleResidualStyleCloseTagAcrossBlocks):
(WebCore::HTMLParser::popBlock):
Cap the number of residual style tags that we are willing to reopen. We will reopen at most 200
residual style tags, since the assumption is that once that many tags are on the stack, you're probably already
every kind of bold, italic, and color of the rainbow.
* rendering/RenderFlow.cpp:
(WebCore::RenderFlow::absoluteClippedOverflowRect):
absoluteClippedOverflowRect can just return the empty rect when the inline flow has no line boxes instead of
doing a bunch of work (and calling containingBlock()) for no reason.
* rendering/RenderInline.cpp:
(WebCore::RenderInline::addChildToFlow):
Remove the useless containingBlock() check from addChildToFlow. Obviously every inline's containing block
is a block flow.
* rendering/bidi.cpp:
(WebCore::inlineWidth):
(WebCore::RenderBlock::createLineBoxes):
Cap the depth of individual line trees to 200. Again the assumption is that once that many open inlines exist
all on one line that there's no way this would be intentional.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@21061 268f45cc-cd09-0410-ab3c-d52691b4dbfc
7 files changed
