[Kde-pim] Re: EntityTreeModel doesn't handle setData(Item) calls in quick succession

[David Jarvie]

On Mon, September 27, 2010 4:48 pm, Sérgio Martins wrote:
> On Mon, Sep 27, 2010 at 12:11 PM, Stephen Kelly <steveire at gmail.com>
> wrote:
>> Stephen Kelly wrote:
>>
>>> Correct. This is something I've been meaning to find a solution for for
>>> a
>>> while. I'd like it to be solved on a Session level, or at least on a
>>> generic level. Volker said there was something in KOrg for this as a
>>> starting point?
>>
>> Sergio do you know something about this? I think you wrote the code I
>> mentioned here. Can it be made generic and put into session?
>
> I had this problem in korg:
>
> 1. modifyJob1 for itemA is created (and revision is incremented
> internally).
>
> 2. User does more changes on the same item.
>
> 3. KOrg knows modifyJob1 didn't finish yet, so it keeps¹ the change
> and will only trigger a 2nd modifyJob when the first ends.
>
> 4. modifyJob1 finishes and KOrg fires modifyJob2.
>
> Problem: The item sent in modifyJob2 still has the old revision,
> because the user was too fast.
>
> Solution: Do an item2.setRevision( item1.revision() ) before fireing
> modifyJob2. This "hack" doesn't break conflict resolution because
> we're certain that the revision we're setting came from us. If an
> external program changes the item, we still get the conflict dialog.
>
>
> Notes:
> ¹ - It doesn't use a queue to keep changes. If change3 appears, only
> change3 is kept, change2 is discarded, and when modifyJob1 finishes,
> change3 is sent.
>
>
> Steve, I don't think there's much to be reused, just used a variable
> to put the latest change on hold, and increment the revision safely.

I implemented a queue in KAlarm before I realised that I was duplicating
ETM's jobs. I'm not sure whether I still have the code - I could look for
it tonight if you want - but it was fairly simple.

-- 
David Jarvie.
KDE developer.
KAlarm author - http://www.astrojar.org.uk/kalarm

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