private void ReconcileWithBaseNode(AssetMemberNode assetNode)
{
if (assetNode?.BaseContent == null || !assetNode.CanOverride)
{
return;
}
var baseNode = (AssetMemberNode)assetNode.BaseContent;
var localValue = assetNode.Retrieve();
var baseValue = assetNode.BaseContent.Retrieve();
// Reconcile occurs only when the node is not overridden.
if (!assetNode.IsContentOverridden())
{
assetNode.ResettingOverride = true;
// Handle null cases first
if (localValue == null || baseValue == null)
{
if (localValue == null && baseValue != null)
{
var clonedValue = CloneValueFromBase(baseValue, assetNode);
assetNode.Update(clonedValue);
}
else if (localValue != null /*&& baseValue == null*/)
{
assetNode.Update(null);
}
}
// Then handle collection and dictionary cases
else if (assetNode.Descriptor is CollectionDescriptor || assetNode.Descriptor is DictionaryDescriptor)
{
// Items to add and to remove are stored in local collections and processed later, since they might affect indices
var itemsToRemove = new List <ItemId>();
var itemsToAdd = new SortedList <object, ItemId>(new DefaultKeyComparer());
// Check for item present in the instance and absent from the base.
foreach (var index in assetNode.Indices)
{
// Skip overridden items
if (assetNode.IsItemOverridden(index))
{
continue;
}
var itemId = assetNode.IndexToId(index);
if (itemId != ItemId.Empty)
{
// Look if an item with the same id exists in the base.
if (!baseNode.HasId(itemId))
{
// If not, remove this item from the instance.
itemsToRemove.Add(itemId);
}
}
else
{
// This case should not happen, but if we have an empty id due to corrupted data let's just remove the item.
itemsToRemove.Add(itemId);
}
}
// Clean items marked as "override-deleted" that are absent from the base.
var ids = CollectionItemIdHelper.GetCollectionItemIds(localValue);
foreach (var deletedId in ids.DeletedItems.ToList())
{
if (assetNode.BaseContent.Indices.All(x => baseNode.IndexToId(x) != deletedId))
{
ids.UnmarkAsDeleted(deletedId);
}
}
// Add item present in the base and missing here, and also update items that have different values between base and instance
foreach (var index in assetNode.BaseContent.Indices)
{
var itemId = baseNode.IndexToId(index);
// TODO: What should we do if it's empty? It can happen only from corrupted data
// Skip items marked as "override-deleted"
if (itemId == ItemId.Empty || assetNode.IsItemDeleted(itemId))
{
continue;
}
Index localIndex;
if (!assetNode.TryIdToIndex(itemId, out localIndex))
{
// For dictionary, we might have a key collision, if so, we consider that the new value from the base is deleted in the instance.
var keyCollision = assetNode.Descriptor is DictionaryDescriptor && (assetNode.ItemReferences?.HasIndex(index) == true || assetNode.Indices.Any(x => index.Equals(x)));
// For specific collections (eg. EntityComponentCollection) it might not be possible to add due to other kinds of collisions or invalid value.
var itemRejected = !CanUpdate(assetNode, ContentChangeType.CollectionAdd, localIndex, baseNode.Retrieve(index));
// We cannot add the item, let's mark it as deleted.
if (keyCollision || itemRejected)
{
var instanceIds = CollectionItemIdHelper.GetCollectionItemIds(assetNode.Retrieve());
instanceIds.MarkAsDeleted(itemId);
}
else
{
// Add it if the key is available for add
itemsToAdd.Add(index.Value, itemId);
}
}
else
{
// If the item is present in both the instance and the base, check if we need to reconcile the value
var member = assetNode as IMemberNode;
var targetNode = assetNode.ItemReferences?[localIndex]?.TargetNode;
// Skip it if it's overridden
if (!assetNode.IsItemOverridden(localIndex))
{
var localItemValue = assetNode.Retrieve(localIndex);
var baseItemValue = baseNode.Retrieve(index);
if (ShouldReconcileItem(member, targetNode, localItemValue, baseItemValue, assetNode.ItemReferences != null))
{
var clonedValue = CloneValueFromBase(baseItemValue, assetNode);
assetNode.Update(clonedValue, localIndex);
}
}
// In dictionaries, the keys might be different between the instance and the base. We need to reconcile them too
if (assetNode.Descriptor is DictionaryDescriptor && !assetNode.IsKeyOverridden(localIndex))
{
if (ShouldReconcileItem(member, targetNode, localIndex.Value, index.Value, false))
{
// Reconcile using a move (Remove + Add) of the key-value pair
var clonedIndex = new Index(CloneValueFromBase(index.Value, assetNode));
var localItemValue = assetNode.Retrieve(localIndex);
assetNode.Remove(localItemValue, localIndex);
assetNode.Add(localItemValue, clonedIndex);
ids[clonedIndex.Value] = itemId;
}
}
}
}
// Process items marked to be removed
foreach (var item in itemsToRemove)
{
var index = assetNode.IdToIndex(item);
var value = assetNode.Retrieve(index);
assetNode.Remove(value, index);
// We're reconciling, so let's hack the normal behavior of marking the removed item as deleted.
ids.UnmarkAsDeleted(item);
}
// Process items marked to be added
foreach (var item in itemsToAdd)
{
var baseIndex = baseNode.IdToIndex(item.Value);
var baseItemValue = baseNode.Retrieve(baseIndex);
var clonedValue = CloneValueFromBase(baseItemValue, assetNode);
if (assetNode.Descriptor is CollectionDescriptor)
{
// In a collection, we need to find an index that matches the index on the base to maintain order.
// To do so, we iterate from the index in the base to zero.
var currentBaseIndex = baseIndex.Int - 1;
// Initialize the target index to zero, in case we don't find any better index.
var localIndex = new Index(0);
// Find the first item of the base that also exists (in term of id) in the local node, iterating backward (from baseIndex to 0)
while (currentBaseIndex >= 0)
{
ItemId baseId;
// This should not happen since the currentBaseIndex comes from the base.
if (!baseNode.TryIndexToId(new Index(currentBaseIndex), out baseId))
{
throw new InvalidOperationException("Cannot find an identifier matching the index in the base collection");
}
Index sameIndexInInstance;
// If we have an matching item, we want to insert right after it
if (assetNode.TryIdToIndex(baseId, out sameIndexInInstance))
{
localIndex = new Index(sameIndexInInstance.Int + 1);
break;
}
currentBaseIndex--;
}
assetNode.Restore(clonedValue, localIndex, item.Value);
}
else
{
// This case is for dictionary. Key collisions have already been handle at that point so we can directly do the add without further checks.
assetNode.Restore(clonedValue, baseIndex, item.Value);
}
}
}
// Finally, handle single properties
else
{
var member = assetNode as IMemberNode;
var targetNode = assetNode.TargetReference?.TargetNode;
if (ShouldReconcileItem(member, targetNode, localValue, baseValue, assetNode.TargetReference != null))
{
var clonedValue = CloneValueFromBase(baseValue, assetNode);
assetNode.Update(clonedValue);
}
}
assetNode.ResettingOverride = false;
}
}
public NodeOverride(AssetMemberNode overriddenNode, Index overriddenIndex, OverrideTarget target)
{
Node = overriddenNode;
Index = overriddenIndex;
Target = target;
}