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Re: [UndoManager] Re-introduce DOMTransaction interface?

From: Adam Barth <w3c@adambarth.com>
Date: Thu, 5 Jul 2012 07:15:02 -0700
Message-ID: <CAJE5ia81hzsniNJZjJOVOJdYM_HOOw9jFi6rRnDoh13cb+XrvA@mail.gmail.com>
To: olli@pettay.fi
Cc: Ryosuke Niwa <rniwa@webkit.org>, public-webapps <public-webapps@w3.org>, Ojan Vafai <ojan@chromium.org>, Jonas Sicking <jonas@sicking.cc>, Ehsan Akhgari <ehsan@mozilla.com>, Erik Arvidsson <arv@chromium.org>, Sukolsak Sakshuwong <sukolsak@gmail.com>, Aryeh Gregor <ayg@aryeh.name>
On Thu, Jul 5, 2012 at 1:37 AM, Olli Pettay <Olli.Pettay@helsinki.fi> wrote:
> On 07/05/2012 08:00 AM, Adam Barth wrote:
>> On Wed, Jul 4, 2012 at 5:25 PM, Olli Pettay <Olli.Pettay@helsinki.fi>
>> wrote:
>>> On 07/05/2012 03:11 AM, Ryosuke Niwa wrote:
>>> So, it is very much implementation detail.
>>>
>>> (And I still don't understand how a callback can be so hard in this case.
>>> There are plenty of different kinds of callback objects.
>>>   new MutationObserver(some_callback_function_object) )
>>
>> I haven't tested, by my reading of the MutationObserver implementation
>> in WebKit is that it leaks.  Specifically:
>>
>> MutationObserver --retains--> MutationCallback --retains-->
>> some_callback_function_object --retains--> MutationObserver
>>
>> I don't see any code that breaks this cycle.
>
> Ok. In Gecko cycle collector breaks the cycle. But very much an
> implementation detail.
>
>> DOM events
>
> Probably EventListeners, not Events.
>
>> have a bunch of delicate code to avoid break these
>> reference cycles and avoid leaks.  We can re-invent that wheel here,
>
> Or use some generic approach to fix such leaks.
>
>> but it's going to be buggy and leaky.
>
> In certain kinds of implementations.
>
>> I appreciatie that these jQuery-style APIs are fashionable at the
>> moment, but API fashions come and go.  If we use this approach, we'll
>> need to maintain this buggy, leaky code forever.
>
> Implementation detail. Very much so :)

Right, my point is that this style of API is difficult to implement
correctly, which means authors will end up suffering low-quality
implementations for a long time.

On Thu, Jul 5, 2012 at 2:22 AM, Olli Pettay <Olli.Pettay@helsinki.fi> wrote:
> But anyhow, event based API is ok to me.
> In general I prefer events/event listeners over other callbacks.

Great.  I'd recommend going with that approach because it will let us
provide authors with high-quality implementations of the spec much
sooner.

Adam
Received on Thursday, 5 July 2012 14:16:04 GMT

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