internal static bool ProcessChangeSourceItem <TSourceItem>(int sourceIndex,
TSourceItem sourceItem,
List <FilteringItemInfo> filteringItemInfos,
IFiltering <TSourceItem> filtering,
Positions <Position> filteredPositions,
CollectionComputing <TSourceItem> current,
ExpressionWatcher expressionWatcher)
{
if (expressionWatcher._disposed)
{
return(false);
}
FilteringItemInfo itemInfo = filteringItemInfos[sourceIndex];
bool newPredicateValue = filtering.applyPredicate(sourceItem, itemInfo.PredicateFunc);
bool oldPredicateValue = itemInfo.FilteredPosition != null;
if (newPredicateValue != oldPredicateValue)
{
if (newPredicateValue)
{
int newIndex = itemInfo.NextFilteredItemPosition.Index;
itemInfo.FilteredPosition = filteredPositions.Insert(newIndex);
newIndex = itemInfo.FilteredPosition.Index;
modifyNextFilteredItemIndex(sourceIndex, itemInfo.FilteredPosition, filteringItemInfos);
current.baseInsertItem(newIndex, sourceItem);
return(true);
}
else // if (oldPredicaeValue)
{
int index = itemInfo.FilteredPosition.Index;
filteredPositions.Remove(index);
itemInfo.FilteredPosition = null;
modifyNextFilteredItemIndex(sourceIndex, itemInfo.NextFilteredItemPosition, filteringItemInfos);
current.baseRemoveItem(index);
return(true);
}
}
return(false);
}
//TODO Uncomment new feature and write test
//[ObservableComputationsCall]
//public Filtering<TSourceItem> TryConstructInsertOrRemoveRequestHandlers()
//{
// ConstructInsertOrRemoveActionsVisitor
// constructInsertOrRemoveActionsVisitor =
// new ConstructInsertOrRemoveActionsVisitor();
// constructInsertOrRemoveActionsVisitor.Visit(_predicateExpressionOriginal);
// Action<TSourceItem> transformSourceItemIntoMember =
// constructInsertOrRemoveActionsVisitor.TransformSourceItemIntoMember;
// if (transformSourceItemIntoMember != null)
// {
// InsertItemRequestHandler = (index, item) => transformSourceItemIntoMember(item);
// }
// Action<TSourceItem> transformSourceItemNotIntoMember =
// constructInsertOrRemoveActionsVisitor.TransformSourceItemIntoNotMember;
// if (transformSourceItemNotIntoMember != null)
// {
// RemoveItemRequestHandler = index => transformSourceItemNotIntoMember(this[index]);
// }
// return this;
//}
//private class ConstructInsertOrRemoveActionsVisitor : ExpressionVisitor
//{
// public Action<TSourceItem> TransformSourceItemIntoMember;
// public Action<TSourceItem> TransformSourceItemIntoNotMember;
// #region Overrides of ExpressionVisitor
// //TODO !sourceItem.NullableProp.HasValue должно преобразооваться в sourceItem.NullableProp == null
// // TODO обрабытывать выражения типа '25 == sourceItem.Id'
// protected override Expression VisitBinary(BinaryExpression node)
// {
// ExpressionType nodeType = node.NodeType;
// if (nodeType == ExpressionType.Equal || nodeType == ExpressionType.NotEqual)
// {
// if (node.Left is MemberExpression memberExpression)
// {
// Expression rightExpression = node.Right;
// // ReSharper disable once PossibleNullReferenceException
// MemberInfo memberExpressionMember = memberExpression.Member;
// Type declaringType = memberExpressionMember.DeclaringType;
// // ReSharper disable once PossibleNullReferenceException
// if (declaringType.IsConstructedGenericType
// && declaringType.GetGenericTypeDefinition() == typeof(Nullable<>)
// && memberExpressionMember.Name == "Value")
// {
// memberExpression = (MemberExpression) memberExpression.Expression;
// rightExpression = Expression.Convert(rightExpression,
// typeof (Nullable<>).MakeGenericType(node.Left.Type));
// }
// ParameterExpression parameterExpression = getParameterExpression(memberExpression);
// if (parameterExpression != null)
// {
// if (memberExpression.Type != rightExpression.Type)
// {
// rightExpression = Expression.Convert(rightExpression, memberExpression.Type);
// }
// if (!memberExpressionMember.IsReadOnly())
// {
// if (nodeType == ExpressionType.Equal)
// {
// TransformSourceItemIntoMember = Expression.Lambda<Action<TSourceItem>>(Expression.Assign(memberExpression, rightExpression), parameterExpression).Compile();
// }
// else if (nodeType == ExpressionType.NotEqual)
// {
// TransformSourceItemIntoNotMember = Expression.Lambda<Action<TSourceItem>>(Expression.Assign(memberExpression, rightExpression), parameterExpression).Compile();
// }
// }
// }
// }
// }
// return node;
// }
// private ParameterExpression getParameterExpression(MemberExpression memberExpression)
// {
// if (memberExpression.Expression is ParameterExpression parameterExpression)
// {
// return parameterExpression;
// }
// if (memberExpression.Expression is MemberExpression expressionMemberExpression)
// {
// return getParameterExpression(expressionMemberExpression); // memberExpression.Expression может быть не MemberExpression
// }
// return null;
// }
// #endregion
//}
protected override void processSource()
{
int originalCount = _items.Count;
if (_sourceReadAndSubscribed)
{
Utils.disposeExpressionItemInfos(_itemInfos, _predicateExpressionCallCount, this);
Utils.removeDownstreamConsumedComputing(_itemInfos, this);
_filteredPositions = new Positions <Position>(new List <Position>(_initialCapacity));
Utils.disposeSource(
_sourceScalar,
_source,
out _itemInfos,
out _sourcePositions,
_sourceAsList,
handleSourceCollectionChanged);
_sourceReadAndSubscribed = false;
}
Utils.changeSource(ref _source, _sourceScalar, _downstreamConsumedComputings, _consumers, this, out _sourceAsList, false);
if (_source != null && _isActive)
{
Utils.initializeFromObservableCollectionWithChangeMarker(
_source,
ref _sourceAsList,
ref _rootSourceWrapper,
ref _lastProcessedSourceChangeMarker);
Position nextItemPosition = _filteredPositions.Add();
int count = _sourceAsList.Count;
TSourceItem[] sourceCopy = new TSourceItem[count];
_sourceAsList.CopyTo(sourceCopy, 0);
_sourceAsList.CollectionChanged += handleSourceCollectionChanged;
int insertingIndex = 0;
int sourceIndex;
for (sourceIndex = 0; sourceIndex < count; sourceIndex++)
{
TSourceItem sourceItem = sourceCopy[sourceIndex];
Position currentFilteredItemPosition = null;
FilteringItemInfo itemInfo = registerSourceItem(sourceItem, sourceIndex, null, null);
if (_thisAsFiltering.applyPredicate(sourceItem, itemInfo.PredicateFunc))
{
if (originalCount > insertingIndex)
{
_items[insertingIndex++] = sourceItem;
}
else
{
_items.Insert(insertingIndex++, sourceItem);
}
currentFilteredItemPosition = nextItemPosition;
nextItemPosition = _filteredPositions.Add();
}
itemInfo.FilteredPosition = currentFilteredItemPosition;
itemInfo.NextFilteredItemPosition = nextItemPosition;
}
for (int index = originalCount - 1; index >= insertingIndex; index--)
{
_items.RemoveAt(index);
}
_sourceReadAndSubscribed = true;
}
else
{
_items.Clear();
}
reset();
}
