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 void ProcessItem(MergeContainer[] sourceLists, ChangeAwareListWithRefCounts <T> resultingList, T item)
{
//check whether the item should be removed from the list
var isInResult = resultingList.Contains(item);
var shouldBeInResult = MatchesConstraint(sourceLists, item);
if (shouldBeInResult)
{
if (!isInResult)
{
resultingList.Add(item);
}
}
else
{
if (isInResult)
{
resultingList.Remove(item);
}
}
}
private IChangeSet <T> UpdateResultList(IChangeSet <T> changes, List <ReferenceCountTracker <T> > sourceLists, ChangeAwareListWithRefCounts <T> resultList)
{
//child caches have been updated before we reached this point.
foreach (var change in changes.Flatten())
{
var item = change.Current;
var isInResult = resultList.Contains(item);
var shouldBeInResult = MatchesConstraint(sourceLists, item);
if (shouldBeInResult)
{
if (!isInResult)
{
resultList.Add(item);
}
}
else
{
if (isInResult)
{
resultList.Remove(item);
}
}
}
return(resultList.CaptureChanges());
}
public IObservable <IChangeSet <T> > Run()
{
return(Observable.Create <IChangeSet <T> >(observer =>
{
//this is the resulting list which produces all notifications
var resultList = new ChangeAwareListWithRefCounts <T>();
//Transform to a merge container.
//This populates a RefTracker when the original source is subscribed to
var sourceLists = _source.Connect()
.Synchronize(_locker)
.Transform(changeset => new MergeContainer(changeset))
.AsObservableList();
//merge the items back together
var allChanges = sourceLists.Connect()
.MergeMany(mc => mc.Source)
.Synchronize(_locker)
.Subscribe(changes =>
{
//Populate result list and chck for changes
var notifications = UpdateResultList(sourceLists.Items.AsArray(), resultList, changes);
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
});
//when an list is removed, need to
var removedItem = sourceLists.Connect()
.OnItemRemoved(mc =>
{
//Remove items if required
var notifications = ProcessChanges(sourceLists.Items.AsArray(), resultList, mc.Tracker.Items);
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
if (_type == CombineOperator.And || _type == CombineOperator.Except)
{
var itemsToCheck = sourceLists.Items.SelectMany(mc2 => mc2.Tracker.Items).ToArray();
var notification2 = ProcessChanges(sourceLists.Items.AsArray(), resultList, itemsToCheck);
if (notification2.Count != 0)
{
observer.OnNext(notification2);
}
}
})
.Subscribe();
//when an list is added or removed, need to
var sourceChanged = sourceLists.Connect()
.WhereReasonsAre(ListChangeReason.Add, ListChangeReason.AddRange)
.ForEachItemChange(mc =>
{
var notifications = ProcessChanges(sourceLists.Items.AsArray(), resultList, mc.Current.Tracker.Items);
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
if (_type == CombineOperator.And || _type == CombineOperator.Except)
{
var notification2 = ProcessChanges(sourceLists.Items.AsArray(), resultList, resultList.ToArray());
if (notification2.Count != 0)
{
observer.OnNext(notification2);
}
}
})
.Subscribe();
return new CompositeDisposable(sourceLists, allChanges, removedItem, sourceChanged);
}));
}
private IChangeSet <T> ProcessChanges(MergeContainer[] sourceLists, ChangeAwareListWithRefCounts <T> resultingList, IEnumerable <T> items)
{
//check whether the item should be removed from the list
items.ForEach(item => { ProcessItem(sourceLists, resultingList, item); });
return(resultingList.CaptureChanges());
}
private IChangeSet <T> UpdateResultList(MergeContainer[] sourceLists, ChangeAwareListWithRefCounts <T> resultingList, IChangeSet <T> changes)
{
//child caches have been updated before we reached this point.
changes.Flatten().ForEach(change => { ProcessItem(sourceLists, resultingList, change.Current); });
return(resultingList.CaptureChanges());
}