[webkit-reviews] review requested: [Bug 50996] Consider disabling DNS prefetch when proxy is used : [Attachment 76700] updated patch

[bugzilla-daemon at webkit.org]

Alexey Proskuryakov <ap at webkit.org> has asked  for review:
Bug 50996: Consider disabling DNS prefetch when proxy is used
https://bugs.webkit.org/show_bug.cgi?id=50996

Attachment 76700: updated patch
https://bugs.webkit.org/attachment.cgi?id=76700&action=review

------- Additional Comments from Alexey Proskuryakov <ap at webkit.org>
> Don’t you need to use CFNumberGetValue instead? Is comparing a CFNumber of 0
a good enough way to check? CFNumberGetValue does some conversion.

When checking that, I came to the conclusion that we can't second-guess
CFNetwork here. The logic is much more complicated - for example, an *Enabled
key can be missing altogether if there are keys for port and host.

So, I changed the code to use a CFNetwork API.

> We should either prove it’s not slow or do something to make sure we’re not
affected.

This worries me, too.

Shark sees the proxyIsEnabledInSystemPreferences(), but on one sample out of
6500. I've also made the check happen later, as the queue coalesces identical
requests.