Akonadi Calendar Dataengine

[Aaron J. Seigo]

On April 6, 2010, Frederik Gladhorn wrote:
> What if I get a second sourceRequestEvent() for the same source string? Do

if the source already exists, it won't get called again.

sourceRequestEvent is *only* called when the source does not exist. once it 
exists, calls are made to updateSourEvent as needed (e.g. due to a connected 
visualization requesting a polling interval when calling connectSource). the 
DataEngine may also decide to update the source on its own.

there are a few issues i see in the current code in playground:

a) eventData["StartDate"] = model->index(row, 
Akonadi::CalendarModel::DateTimeStart).data().toDateTime().toString();

that last toString() probably isn't needed. puting the QDateTime object in 
there is just fine.


b) this is in akonadiCalendarSourceRequest, but it should be in 
initAkonadiCalendar (to avoid multiple connections):

 connect(m_calendarModel, SIGNAL(rowsInserted(QModelIndex, int , int )),
            this, SLOT(calendarModelRowsInserted(QModelIndex,int,int)));


c) when a source is requested, akonadiCalendarSourceRequest is called. this 
creates a new Akonadi::DateRangeFilterProxyModel and that remains around for 
the lifetime of the engine.

what i'd recommend here is creating a subclass of Plasma::DataContainer that 
has the Akonadi::DateRangeFilterProxyModel as a member. then in 
sourceRequetEvent, the engine could just do something like:

initAkonadiCalendar();
addSource(new AkonadiDateRangeSource(name, start, end));
return true;

this hypothetical AkonadiDateRangeSource class would subclass 
Plasma::DataContainer, call setObjectName(name) in its constructor, connect 
the signals to itself which call setData() on itself as appropriate and then 
setNeedsUpdate() (which schedules the signals for the visualizations that are 
connected).

this way, when the source goes out of use (e.g. all the visualizations 
disconnect from it) then the Akonadi::DateRangeFilterProxyModel would also get 
deleted. it would also move all of the Akonadi code related to the events date 
ranges out into its own class (nice for code clarity)

-- 
Aaron J. Seigo
humru othro a kohnu se
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