+2012-09-25 Antti Koivisto <antti@apple.com>
+
+ Optimize stylesheet insertions
+ https://bugs.webkit.org/show_bug.cgi?id=97627
+
+ Reviewed by Andreas Kling.
+
+ We currently do scope analysis for stylesheets that are added to the end of the active stylesheet list to avoid unnecessary style
+ recalcs and StyleResolver rebuilding. However it is somewhat common to insert <style> elements dynamically to positions other than last.
+ In this case we currently simply force full style recalc. We should do scope analysis and partial style recalcs also in these cases.
+
+ PerformanceTests/CSS/StyleSheetInsert.html microbenchmark shows ~20x progression from the patch.
+
+ * css/StyleResolver.cpp:
+ (WebCore::StyleResolver::StyleResolver):
+ (WebCore::StyleResolver::resetAuthorStyle):
+
+ Add a way to reset author RuleSet without deleting the whole StyleResolver.
+
+ (WebCore):
+ * css/StyleResolver.h:
+ (StyleResolver):
+ * dom/DocumentStyleSheetCollection.cpp:
+ (WebCore::DocumentStyleSheetCollection::analyzeStyleSheetChange):
+
+ Check if there have been insertions to the stylesheet list. If so we need to reset
+ the StyleResolver (to handle rule position changes) but don't need to force full
+ style recalc. Do scope analysis for inserted stylesheets as well.
+
+ (WebCore::DocumentStyleSheetCollection::updateActiveStyleSheets):
+ * dom/DocumentStyleSheetCollection.h:
+
git://git.webkit.org / WebKit-https.git / blobdiff