Implement -forwardingTargetForSelector on WKScrollViewDelegateForwarder

• Component: WebKit2
• Status: RESOLVED FIXED

[Tim Horton]

This is a ~4.3% win on UI process total time (5%->0.7%) running http://www.kevs3d.co.uk/dev/canvasmark/, as predicted by https://bugs.webkit.org/show_bug.cgi?id=127085#c2.

[Radar WebKit Bug Importer]

<rdar://problem/16877802>

[Tim Horton]

Created attachment 231244 [details]
patch

Comment on attachment 231244 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=231244&action=review

> Source/WebKit2/UIProcess/ios/WKScrollView.mm:91
> +    BOOL internalDelegateWillRespond = [_internalDelegate respondsToSelector:aSelector];
> +    BOOL externalDelegateWillRespond = [_externalDelegate respondsToSelector:aSelector];

We could make things even faster by caching these for some or all selectors.

> Source/WebKit2/UIProcess/ios/WKScrollView.mm:97
> +    return self;

The documentation for -forwardingTargetForSelector: says
    (Obviously if you return self from this method, the code would just fall into an infinite loop.)
Why are you returning self?

[Tim Horton]

(In reply to comment #3)
> (From update of attachment 231244 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=231244&action=review
> 
> > Source/WebKit2/UIProcess/ios/WKScrollView.mm:91
> > +    BOOL internalDelegateWillRespond = [_internalDelegate respondsToSelector:aSelector];
> > +    BOOL externalDelegateWillRespond = [_externalDelegate respondsToSelector:aSelector];
> 
> We could make things even faster by caching these for some or all selectors.
> 
> > Source/WebKit2/UIProcess/ios/WKScrollView.mm:97
> > +    return self;
> 
> The documentation for -forwardingTargetForSelector: says
>     (Obviously if you return self from this method, the code would just fall into an infinite loop.)
> Why are you returning self?

Ha! I missed that, and misunderstood the fallback case. Also that suggests to me that we never run into this case, because I haven't seen any infinite loops yet today :D

[Tim Horton]

Created attachment 231246 [details]
patch

[Tim Horton]

http://trac.webkit.org/changeset/168593