public IObservable <IChangeSet <T> > Run()
{
return(Observable.Create <IChangeSet <T> >(observer =>
{
var locker = new object();
var orginal = new ChangeAwareList <T>();
var target = new ChangeAwareList <T>();
var changed = _source.Synchronize(locker).Select(changes =>
{
if (_resetThreshold > 1)
{
orginal.Clone(changes);
}
return changes.TotalChanges > _resetThreshold && _comparer != null ? Reset(orginal, target) : Process(target, changes);
});
var resort = _resort.Synchronize(locker).Select(changes => Reorder(target));
var changeComparer = _comparerObservable.Synchronize(locker).Select(comparer => ChangeComparer(target, comparer));
return changed.Merge(resort).Merge(changeComparer)
.Where(changes => changes.Count != 0)
.SubscribeSafe(observer);
}));
}
public Continuation <IChangeSet <T> > Write(IChangeSet <T> changes)
{
if (changes == null)
{
throw new ArgumentNullException(nameof(changes));
}
IChangeSet <T> result;
lock (_locker)
{
try
{
_data.Clone(changes);
result = _data.CaptureChanges();
}
catch (Exception ex)
{
return(new Continuation <IChangeSet <T> >(ex));
}
}
return(new Continuation <IChangeSet <T> >(result));
}
private IChangeSet <T> ProcessImpl(ChangeAwareList <T> target, IChangeSet <T> changes)
{
if (_comparer == null)
{
target.Clone(changes);
return(target.CaptureChanges());
}
foreach (var change in changes)
{
switch (change.Reason)
{
case ListChangeReason.Add:
{
var current = change.Item.Current;
Insert(target, current);
break;
}
case ListChangeReason.AddRange:
{
var ordered = change.Range.OrderBy(t => t, _comparer).ToList();
if (target.Count == 0)
{
target.AddRange(ordered);
}
else
{
ordered.ForEach(item => Insert(target, item));
}
break;
}
case ListChangeReason.Replace:
{
var current = change.Item.Current;
//TODO: check whether an item should stay in the same position
//i.e. update and move
Remove(target, change.Item.Previous.Value);
Insert(target, current);
break;
}
case ListChangeReason.Remove:
{
var current = change.Item.Current;
Remove(target, current);
break;
}
case ListChangeReason.RemoveRange:
{
target.RemoveMany(change.Range);
break;
}
case ListChangeReason.Clear:
{
target.Clear();
break;
}
}
}
return(target.CaptureChanges());
}
