public IObservable <IChangeSet <T> > Run()
{
return(Observable.Create <IChangeSet <T> >(observer =>
{
var disposable = new CompositeDisposable();
var sourceLists = new List <ReferenceCountTracker <T> >();
var resultList = new ChangeAwareListWithRefCounts <T>();
lock (_locker)
{
foreach (var item in _source)
{
var list = new ReferenceCountTracker <T>();
sourceLists.Add(list);
disposable.Add(item.Synchronize(_locker).Subscribe(changes =>
{
CloneSourceList(list, changes);
var notifications = UpdateResultList(changes, sourceLists, resultList);
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
}));
}
}
return disposable;
}));
}
private static void CloneSourceList(ReferenceCountTracker <T> tracker, IChangeSet <T> changes)
{
foreach (var change in changes)
{
switch (change.Reason)
{
case ListChangeReason.Add:
tracker.Add(change.Item.Current);
break;
case ListChangeReason.AddRange:
foreach (var t in change.Range)
{
tracker.Add(t);
}
break;
case ListChangeReason.Replace:
tracker.Remove(change.Item.Previous.Value);
tracker.Add(change.Item.Current);
break;
case ListChangeReason.Remove:
tracker.Remove(change.Item.Current);
break;
case ListChangeReason.RemoveRange:
case ListChangeReason.Clear:
foreach (var t in change.Range)
{
tracker.Remove(t);
}
break;
}
}
}