Bug 160712 – CharacterData.data setter optimization is not spec-compliant and is observable

• Component: DOM
• Status: RESOLVED FIXED

[Chris Dumez]

We have an optimization in CharacterData.setData() that avoid doing any work if the new data is identical to the old data. However, this optimization is not spec-compliant:
- https://dom.spec.whatwg.org/#dom-characterdata-data

This is an issue because this is observable using DOM mutation observer or ranges.

[Chris Dumez]

Created attachment 285682 [details]
Patch

[Ryosuke Niwa]

Comment on attachment 285682 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=285682&action=review

> Source/WebCore/dom/CharacterData.cpp:44
> +    auto& document = node.document();
> +    return !document.hasListenerType(Document::DOMCHARACTERDATAMODIFIED_LISTENER) && !document.hasMutationObserversOfType(MutationObserver::CharacterData);

We also need to check subtreemodified event.

> Source/WebCore/dom/CharacterData.cpp:53
> +        document().textRemoved(this, 0, oldLength);

We also need to call document().frame()->selection().textWasReplaced to be consistent.

[Chris Dumez]

Created attachment 285685 [details]
Patch

[Chris Dumez]

Created attachment 285689 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 285689 [details]
Patch

Clearing flags on attachment: 285689

Committed r204316: <http://trac.webkit.org/changeset/204316>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.