On Oct 4, 2010, at 11:31 AM, Tony Gentilcore wrote:
> If you subclass RefCounted<T> or Noncopyable, which is very common, you pick
> up FastAllocBase.
Yes, so in those cases you don’t want to use it.
> So, my naive guess is that any class/struct which doesn't pick up
> FastAllocBase through its inheritance chain should subclass it directly. Is
> that a reasonable guideline?
That’s OK, but:
1) FastAllocBase has been causing object size bloat, so we are planning to
switch from base classes to macros. See bug 42998
<https://bugs.webkit.org/show_bug.cgi?id=42998>.
2) If the object will not ever be allocated with new, there is no benefit
to deriving from FastAllocBase.
3) Our original plan was to that on platforms where
ENABLE_GLOBAL_FASTMALLOC_NEW, such as Mac OS X, we would change the operator
new to check at runtime and immediately assert in debug builds if someone
forgot to use FastAllocBase. But as you can see if you look at FastMalloc.h,
this has not been done yet.
So for the moment it’s fine to follow the guideline you mention, but (1) will
change how we do it soon, (2) is worth considering, and (3) will eventually
make the guideline clearer than it is now because we’ll notice when we do it
wrong!
-- Darin
_______________________________________________
webkit-dev mailing list
webkit-dev@lists.webkit.org
http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
