> On 2010-09-10 23:56:04, Aaron Seigo wrote:
> > if there is nothing connected to it, why would it want to fill that data?
> > if nothing is connected, then there is precisely no reason to deliver that
> > data. it sounds like the system monitor engine is doing something wrong.
>
> Alex Merry wrote:
> System monitor maintains its list of sources (ie: things that can be
> monitored) by maintaining a bunch of DataContainers. Ordinarily, these just
> have some meta-information about the thing being monitored, such as a
> human-readable name and the units. Only when a source is connected to are
> the values updated.
>
> This is not an unusual approach to take, as far as I'm aware - that's
> kind of the point of DataContainer, right? It's just that systemmonitor
> doesn't bother subclassing DataContainer, but instead uses it directly.
>
> Note that the way KSysGuard works means that if it fetches the list of
> things that can be monitored, it has to fetch the meta-info as well, so it
> may as well store it. The issue is simply that it has to fetch this
> asynchonously, and visualizations may request a source before it has done so.
>
> Aaron Seigo wrote:
> "This is not an unusual approach to take"
>
> no, it is quite unusual. a DataContainer, once added to an engine due to
> a sourceRequestEvents not only represents that source but the source has the
> lifespan of the request.
>
> instead, what it ought to do is add all the DataContainers using
> DataEngine::addSource(DataContainer *) and then update them in
> updateRequestEvent. this behaviour can be triggered with
> setMinimumPollingInterval(0). this is documented in the apidox and is the way
> to get the desired behavior.
>
> so, yes, SystemMonitor is at fault here :)
>
> Alex Merry wrote:
> I don't see how that would help.
>
> The issue systemmonitor is trying to deal with is that it finds out what
> sources it should add *after* one of them is requested. So it has the option
> of refusing to deal with the request at all (in which case visualizations
> would need to listen to sourceAdded() - not a problem in itself, but this
> make break existing visualizations using systemmonitor) or adding it in the
> hope that it will be created (the current behaviour, and the cause of the
> problems).
>
> With the latter approach, when it finds out what sources are available,
> it has the choice of populating the existing source (in which case it may
> well be removed by DataEngine at some point) or removing it and re-adding it
> (disconnecting the visualization in the process, defeating the purpose of
> creating the dummy source in the first place).
an easier way around this is to disconnect the DataContainer's becameUnused
signal:
DataContainer *s = containerForSource(source);
if (s) {
disconnect(s, SIGNAL(becameUnused(QString))), this,
SLOT(removeSource(QString)));
}
- Aaron
-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
http://svn.reviewboard.kde.org/r/5312/#review7530
-----------------------------------------------------------
On 2010-09-10 23:30:32, Alex Merry wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://svn.reviewboard.kde.org/r/5312/
> -----------------------------------------------------------
>
> (Updated 2010-09-10 23:30:32)
>
>
> Review request for Plasma.
>
>
> Summary
> -------
>
> Allow DataEngine implementations to prevent DataEngine from automatically
> deleting sources create in sourceRequestEvent.
>
> Rationale: engines that fetch a list of sources asynchronously at creation
> time (such as systemmonitor) may reasonably want to create dummy data sources
> when they are requested before the list has been fetched. However, they
> probably don't want these to be removed again when disconnected from.
>
>
> Diffs
> -----
>
> /trunk/KDE/kdelibs/plasma/dataengine.cpp 1173953
> /trunk/KDE/kdelibs/plasma/private/dataengine_p.h 1173953
> /trunk/KDE/kdelibs/plasma/dataengine.h 1173953
>
> Diff: http://svn.reviewboard.kde.org/r/5312/diff
>
>
> Testing
> -------
>
> It makes the systemmonitor engine work properly. Specifically, it solves the
> bug in bubblemon where if you had the bubblemon displaying, say, CPU Total
> Load when plasma started and then changed it to, say, CPU Idle Load, the CPU
> Total Load source would be removed and there would be an empty place where it
> should be in the list in the config dialog.
>
>
> Thanks,
>
> Alex
>
>
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