Improve the find word boundary performance

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[KyungTae Kim]

Created attachment 219051 [details]
testcase

Currently, the finding end word boundary has poor performance when the word is very wrong.

If you double click on the texts in the attached file, that takes several seconds to select the word.

Both startWordBoudary and endWordBoundary uses findWordBoundary that returns both start and end boundary, then use only start or end boundary.

By using the separate function for finding end word boundary, the word selection performance can be improved by up to 50%.

[KyungTae Kim]

Created attachment 219052 [details]
Patch

[Build Bot]

Comment on attachment 219052 [details]
Patch

Attachment 219052 [details] did not pass mac-wk2-ews (mac-wk2):
Output: http://webkit-queues.appspot.com/results/48138217

[KyungTae Kim]

Created attachment 219057 [details]
Patch

[Sam Weinig]

Comment on attachment 219057 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=219057&action=review

> Source/WebCore/editing/VisibleUnits.cpp:653
> +#if PLATFORM(MAC)

Please don't put platform specific changes in this platform independent file.

[Darin Adler]

It’s OK to do this by adding the new function. We should add a Mac implementation too, even if there is no performance benefit on Mac.

[KyungTae Kim]

Created attachment 219133 [details]
Patch

[Darin Adler]

Comment on attachment 219133 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=219133&action=review

> Source/WebCore/ChangeLog:11
> +        No tests because no operation changes.

Normally we are able to build performance tests that show benefits in cases like this.

> Source/WebCore/platform/text/mac/TextBoundaries.mm:52
> +void findEndWordBoundary(const UChar* chars, int len, int position, int* end)
> +{
> +    NSString* string = [[NSString alloc] initWithCharactersNoCopy:const_cast<unichar*>(chars)
> +        length:len freeWhenDone:NO];
> +    NSAttributedString* attr = [[NSAttributedString alloc] initWithString:string];
> +    NSRange range = [attr doubleClickAtIndex:(position >= len) ? len - 1 : position];
> +    [attr release];
> +    [string release];
> +    *end = range.location + range.length;
> +}

Looks fine. Or we could just have this call findWordBoundary.

[WebKit Commit Bot]

Comment on attachment 219133 [details]
Patch

Clearing flags on attachment: 219133

Committed r160526: <http://trac.webkit.org/changeset/160526>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.