private void Transform(ChangeAwareList <TransformedItemContainer> transformed, IChangeSet <TSource> changes)
{
if (changes == null)
{
throw new ArgumentNullException(nameof(changes));
}
transformed.EnsureCapacityFor(changes);
foreach (var item in changes)
{
switch (item.Reason)
{
case ListChangeReason.Add:
{
var change = item.Item;
if (change.CurrentIndex < 0 | change.CurrentIndex >= transformed.Count)
{
transformed.Add(_containerFactory(change.Current));
}
else
{
transformed.Insert(change.CurrentIndex, _containerFactory(change.Current));
}
break;
}
case ListChangeReason.AddRange:
{
transformed.AddOrInsertRange(item.Range.Select(_containerFactory), item.Range.Index);
break;
}
case ListChangeReason.Replace:
{
var change = item.Item;
if (change.CurrentIndex == change.PreviousIndex)
{
transformed[change.CurrentIndex] = _containerFactory(change.Current);
}
else
{
transformed.RemoveAt(change.PreviousIndex);
transformed.Insert(change.CurrentIndex, _containerFactory(change.Current));
}
break;
}
case ListChangeReason.Remove:
{
var change = item.Item;
bool hasIndex = change.CurrentIndex >= 0;
if (hasIndex)
{
transformed.RemoveAt(item.Item.CurrentIndex);
}
else
{
var toremove = transformed.FirstOrDefault(t => ReferenceEquals(t.Source, t));
if (toremove != null)
{
transformed.Remove(toremove);
}
}
break;
}
case ListChangeReason.RemoveRange:
{
if (item.Range.Index >= 0)
{
transformed.RemoveRange(item.Range.Index, item.Range.Count);
}
else
{
var toremove = transformed.Where(t => ReferenceEquals(t.Source, t)).ToArray();
transformed.RemoveMany(toremove);
}
break;
}
case ListChangeReason.Clear:
{
//i.e. need to store transformed reference so we can correctly clear
var toClear = new Change <TransformedItemContainer>(ListChangeReason.Clear, transformed);
transformed.ClearOrRemoveMany(toClear);
break;
}
case ListChangeReason.Moved:
{
var change = item.Item;
bool hasIndex = change.CurrentIndex >= 0;
if (!hasIndex)
{
throw new UnspecifiedIndexException("Cannot move as an index was not specified");
}
var collection = transformed as IExtendedList <TransformedItemContainer>;
if (collection != null)
{
collection.Move(change.PreviousIndex, change.CurrentIndex);
}
else
{
var current = transformed[change.PreviousIndex];
transformed.RemoveAt(change.PreviousIndex);
transformed.Insert(change.CurrentIndex, current);
}
break;
}
}
}
}
