[Webkit-unassigned] [Bug 157924] REGRESSION (r188642): All pages are blank when printing a webpage in iOS Safari
bugzilla-daemon at webkit.org
bugzilla-daemon at webkit.org
Thu May 19 16:25:51 PDT 2016
https://bugs.webkit.org/show_bug.cgi?id=157924
--- Comment #5 from Andy Estes <aestes at apple.com> ---
(In reply to comment #4)
> There are two issues I think:
>
> 1) The functional style would have you let WTF::Condition do the time math
> for you. Instead of having a wait loop, do:
>
> m_condition.waitFor(m_lock, timeout, [&] () -> bool { loop body });
Unfortunately this would just move the overflow into Condition::absoluteFromRelative(), where have these two lines:
Clock::duration myRelativeTimeout =
std::chrono::duration_cast<Clock::duration>(relativeTimeout);
return Clock::now() + myRelativeTimeout;
libc++ represents both nanoseconds and milliseconds using the same type (long long), so the duration_cast will overflow trying to convert the largest long long into an even larger number of nanosecond ticks. Now we're right back where we started, subtracting from Clock::now() instead of adding.
>
> 2) The style that I've been settling on is to just use doubles for time.
> Maybe when I have time to mess around I'll propose that we do this. I've
> encountered so many bugs due to std::chrono having overflows where our old
> double-based time code would have recovered like a champ. In fact, one of
> those overflows was in GCC's version of libstdc++! It would cause some uses
> of std::condition_variable to freak out on Linux but not anywhere else.
>
> In this case, we could just go back to using a double timeout.
> waitForSeconds(+Inf) should correctly cause our code to recognize that you
> want to timeout forever.
>
> I'm also fine with Geoff's proposed solution.
Yeah, this is basically what I proposed doing in Radar, although now Geoff made me realize that my patch has a totally unnecessary subtraction in it!
Thanks for the feedback, Geoff and Phil.
--
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.webkit.org/pipermail/webkit-unassigned/attachments/20160519/c0b65d7a/attachment-0001.html>
More information about the webkit-unassigned
mailing list