Bug 78812 - Removing the last presentation attribute should result in a null attributeStyle().
Summary: Removing the last presentation attribute should result in a null attributeSty...
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: DOM (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Andreas Kling
URL:
Keywords:
Depends on:
Blocks: 78798
  Show dependency tree / graph
 
Reported: 2012-02-16 07:40 PST by Andreas Kling
Modified: 2012-02-17 01:21 PST (History)
2 users (show)

See Also:

Attachments
Patch (2.65 KB, patch)
2012-02-16 07:45 PST, Andreas Kling 		koivisto: review+
Details | Formatted Diff | Diff
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Andreas Kling 2012-02-16 07:40:50 PST 
Hanging an empty attribute style on a StyledElement is a waste of resources. If updateAttributeStyle() doesn't find any presentation attributes we should set a null attributeStyle.
Comment 1 Andreas Kling 2012-02-16 07:45:48 PST 
Created attachment 127377 [details]
Patch
Comment 2 Andreas Kling 2012-02-16 08:18:01 PST 
Comment on attachment 127377 [details]
Patch

We can avoid the heap allocation altogether if we don't have any presentation attributes..
Comment 3 Andreas Kling 2012-02-16 08:33:12 PST 
Comment on attachment 127377 [details]
Patch

Actually, calling the isPresentationAttribute() virtual on every attribute is more expensive than avoiding the temporary StylePropertySet.
Comment 4 Eric Seidel (no email) 2012-02-16 15:09:58 PST 
So this is a performance fix?  Memory fix?  Or is this in any way visible to the web?
Comment 5 Andreas Kling 2012-02-17 01:02:05 PST 
Committed r108049: <http://trac.webkit.org/changeset/108049>
Comment 6 Andreas Kling 2012-02-17 01:21:01 PST 
(In reply to comment #4)
> So this is a performance fix?  Memory fix?  Or is this in any way visible to the web?

It's a small performance and memory fix for cases where removing an attribute on an element and causing it to no longer have any presentation attributes is slightly more efficient.