[whatwg] Worker lifecycle
mjs at apple.com
Thu May 28 19:47:37 PDT 2009
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.
>>>> 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
>>> only runs at page-closing time.
>> So it's exactly equivalent to the old requirement, except the spec
>> specifically points out that you can just leak forever instead. I
>> 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.
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