On May 28, 2009, at 5:17 PM, Ian Hickson wrote:
On Thu, 28 May 2009, Maciej Stachowiak wrote:
On May 28, 2009, at 1:08 PM, Ian Hickson wrote:
On Thu, 28 May 2009, Maciej Stachowiak wrote:
If so, that seems like it could create unbounded memory leaks in
long-running Web applications that use MessagePorts, even if all
references to both endpoints of the MessageChannel are dropped.
That
seems unacceptable to me, unless I misunderstood.
The requirement is actually indistinguishable from the UA using the
other alternative and just having a really slow garbage collector
that
only runs at page-closing time.
So it's exactly equivalent to the old requirement, except the spec
now
specifically points out that you can just leak forever instead. I
don't
think that addresses the original concern at all.
I've tweaked the text some to make it clear that once the port is not
entangled, it doesn't continue being protected in this way.
The new text seems to be this:
"When a MessagePort object is entangled, user agents must either act
as if the object has a strong reference to its entangledMessagePort
object, or as if the MessagePort object's owner has a strong reference
to the MessagePort object"
It seems to me this allows the following case: two message ports A and
B are entangled. A is treated as having a strong reference to B, but
is not treated as if its owner has a strong reference to it. However,
B is not treated as having a strong reference to A, but is treated as
if its owner has a strong reference to it. Is that intended? I think
this behavior would be practically implementable and quite useful in
many cases, even though it is asymmetric. But I am not sure if the
text intended to allow it.
Regards,
Maciej
