Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 9ca6a02d5b6ab91a124a8b4c11b837b42b3250a3
https://github.com/WebKit/WebKit/commit/9ca6a02d5b6ab91a124a8b4c11b837b42b3250a3
Author: Tyler Wilcock <tyle...@apple.com>
Date: 2025-05-22 (Thu, 22 May 2025)
Changed paths:
A LayoutTests/accessibility/mac/text-marker-ordering-expected.txt
A LayoutTests/accessibility/mac/text-marker-ordering.html
M LayoutTests/platform/mac-wk1/TestExpectations
M Source/WebCore/accessibility/AXCoreObject.cpp
M Source/WebCore/accessibility/AXCoreObject.h
M Source/WebCore/accessibility/AXTextMarker.cpp
M Source/WebCore/accessibility/AXTextMarker.h
M Source/WebCore/accessibility/AccessibilityObject.h
M Source/WebCore/accessibility/isolatedtree/mac/AXIsolatedObjectMac.mm
Log Message:
-----------
AX: AXTextMarker::partialOrderByTraversal is extremely slow on large webpages
https://bugs.webkit.org/show_bug.cgi?id=293257
rdar://151648013
Reviewed by Joshua Hoffman.
When holding VO-Right on html.spec.whatwg.org for 120 seconds, 48.6 seconds are
spent in AXTextMarker::partialOrderByTraversal.
This commit replaces that function with a new one:
AXTextMarker::partialOrderByAncestry. This function walks up and keeps
track of the ancestry for the |this| and |other| text markers. When we find a
shared ancestor, we get the next-most
recent ancestor (which will be different for each), and determine what
child-index it is in the shared ancestor. This
gets us the same information, much faster.
The old method took 48.6 seconds to process 1800 order-comparisons on
html.spec.whatwg.org. The new one takes 4.4ms.
This is also faster in the case of simpler, more common webpages:
YouTube: 0.45ms vs 18.2ms for 237 comparisons
Wikipedia: 3.8ms vs. 18.7ms for 270 comparisons
Behavior covered by existing tests, and new test. I also did manual testing on
html.spec.whatwg.org, YouTube, and Wikipedia where
I RELEASE_ASSERT'd that the new function computed the same thing as the old
one, and did not find any divergent cases.
* LayoutTests/accessibility/mac/text-marker-ordering-expected.txt: Added.
* LayoutTests/accessibility/mac/text-marker-ordering.html: Added.
* LayoutTests/platform/mac-wk1/TestExpectations:
* Source/WebCore/accessibility/AXCoreObject.cpp:
(WebCore::AXCoreObject::partialOrder):
* Source/WebCore/accessibility/AXCoreObject.h:
* Source/WebCore/accessibility/AXTextMarker.cpp:
(WebCore::operator<=>):
(WebCore::AXTextMarker::partialOrderByTraversal const): Deleted.
* Source/WebCore/accessibility/AXTextMarker.h:
(WebCore::AXTextMarker::findLast const):
* Source/WebCore/accessibility/AccessibilityObject.h:
* Source/WebCore/accessibility/isolatedtree/mac/AXIsolatedObjectMac.mm:
(WebCore::AXIsolatedObject::textMarkerRange const):
Canonical link: https://commits.webkit.org/295312@main
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