Use emptyString() instead of "" when possible

[Chris Dumez]

Use emptyString() instead of "" when possible to reduce String allocations.

[Chris Dumez]

Created attachment 283691 [details]
Patch

[Chris Dumez]

Comment on attachment 283691 [details]
Patch

Clearing flags on attachment: 283691

Committed r203250: <http://trac.webkit.org/changeset/203250>

[Chris Dumez]

All reviewed patches have been landed.  Closing bug.

[Elliott Sprehn]

Does this actually save allocations? String("") does StringImpl::create(LChar*) which does strlen and then StringImpl::create(LChar*, unsigned) which does:

https://github.com/adobe/webkit/blob/master/Source/WTF/wtf/text/StringImpl.cpp#L255

    if (!characters || !length)
        return empty();

I think this patch saves branches and function calls, but not allocations?

[Chris Dumez]

(In reply to comment #4)
> Does this actually save allocations? String("") does
> StringImpl::create(LChar*) which does strlen and then
> StringImpl::create(LChar*, unsigned) which does:
> 
> https://github.com/adobe/webkit/blob/master/Source/WTF/wtf/text/StringImpl.
> cpp#L255
> 
>     if (!characters || !length)
>         return empty();
> 
> I think this patch saves branches and function calls, but not allocations?

You're totally right Elliot, I did not know about this optimization in StringImpl.