Bug 62800 – HTMLTable should cache its 'rows' collection results

• Status: RESOLVED
• Resolution: FIXED
• Component: DOM

[Julien Chaffraix]

This stems from http://code.google.com/p/chromium/issues/detail?id=73120

The test page is a 22k table. Some JS code is calling table.rows for each element at least twice. Currently, we create a new HTMLTableRowsCollection every time table.rows is called. This means that the length is potentially recalculated every time table.rows is used.

In the example, the DOM is not mutated so we could potentially reuse the CollectionCache to avoid the bad behavior.

Patch forthcoming.

[Julien Chaffraix]

Created attachment 97451 [details]
Patch

[Darin Adler]

Comment on attachment 97451 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=97451&action=review

> Source/WebCore/html/HTMLTableElement.cpp:630
> +        m_collectionCache = adoptPtr(new CollectionCache());

I usually don’t put in the parentheses in cases like this.

[WebKit Review Bot]

Comment on attachment 97451 [details]
Patch

Clearing flags on attachment: 97451

Committed r89035: <http://trac.webkit.org/changeset/89035>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.

[Darin Adler]

I am seeing crashes when running dom/html/level2/html/HTMLCollection01.html and other tests now.

Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000098
0   com.apple.WebCore             	0x000000010fe13478 WTF::OwnPtr<WebCore::CollectionCache>::operator!() const + 8 (OwnPtr.h:65)
1   com.apple.WebCore             	0x000000010fe8b0e9 WebCore::HTMLTableElement::collectionCache() const + 41 (HTMLTableElement.cpp:629)
2   com.apple.WebCore             	0x000000010fe8ed18 WebCore::HTMLTableRowsCollection::HTMLTableRowsCollection(WTF::PassRefPtr<WebCore::HTMLTableElement>) + 72 (HTMLTableRowsCollection.cpp:153)

Caused by this patch?

[Darin Adler]

Yup, this patch makes incorrect use of PassRefPtr.