util_mark_task_complete_sync

Marks the vtodo as complete with eventual update of other properties.

This is useful also for recurring tasks, for which it moves the vtodo into the next occurrence according to the recurrence rule.

When the vtodo is marked as completed, then the existing COMPLETED date-time is preserved if exists, otherwise it's set either to completed_time, or to the current time, when the completed_time is (time_t) -1.

The function doesn't change LAST-MODIFIED neither the SEQUENCE property, it's up to the caller to do it.

Note the cal_client, cancellable and throws is used only for timezone resolution. The function doesn't store the vtodo to the cal_client, it only updates the vtodo component.

Parameters:

vtodo	a VTODO component
completed_time	completed time to set, or (time_t) -1 to use current time
cal_client	an Client to which the vtodo belongs
cancellable	optional Cancellable object, or null

Returns:

Whether succeeded.