On 2014/05/08 09:17:48, rossberg wrote:
I agree with Michael, that seems too simplistic an implementation. We
need a
proper solution for memory management and rehashing. That requires the
use of
weakness in some form or the other.
Michael and I have discussed this a couple of days ago. The current
implementation with a doubly-linked list of iterators will be very hard to
make
weak correctly. We hence concluded that this is probably the wrong
approach
moving forward. One alternative might be to have each map/set carry a
weak set
of its iterators, and defer rehashing to points where that is empty. But
perhaps
there are other solutions.
I'm also not sure iterators are worth introducing a separate flag, or a
separate
file.
It is true that this ties the lifetime of the iterator and the map
together. It
is a known temporary restriction.
I know how to solve the memory management but I haven't yet been able to
figure
out how to get that working in the V8 code base. I've talked this through
with
Adam so he knows the basics of the solution too.
The idea is to have a single linked list. When GC happens we remove the
collected items from this list. Similar to how you currently do
VisitWeakList
and WeakListVisitor. This means that the Map/Set does not keep the iterator
alive but the iterator keeps the Map/Set alive which is a requirement. I
took
some rough notes when I looked at this last time:
https://docs.google.com/a/google.com/document/d/1-v25eMlmIJFdeAlYEziSV0VXI9QWUSWbdz6tuE-A22o/edit#heading=h.e03fz1pee5xt
This was done as a seperate file because iterators depends on Symbol which
we
are not shipping and no other browser has implemented. Since everyone else
is
shipping Map and Set I didn't want to gate Map and Set on Symbols.
https://codereview.chromium.org/259883002/
--
--
v8-dev mailing list
v8-dev@googlegroups.com
http://groups.google.com/group/v8-dev
---
You received this message because you are subscribed to the Google Groups "v8-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to v8-dev+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
