internal void AddToListAndToVisualTree(UIDocument uiDocument, VisualElement visualTree, int firstInsertIndex = 0)
{
int index = 0;
foreach (var sibling in m_AttachedUIDocuments)
{
if (uiDocument.sortingOrder > sibling.sortingOrder)
{
index++;
continue;
}
if (uiDocument.sortingOrder < sibling.sortingOrder)
{
break;
}
// They're the same value, compare their count (UIDocuments created first show up first).
if (uiDocument.m_UIDocumentCount > sibling.m_UIDocumentCount)
{
index++;
continue;
}
break;
}
if (index < m_AttachedUIDocuments.Count)
{
m_AttachedUIDocuments.Insert(index, uiDocument);
if (visualTree == null || uiDocument.rootVisualElement == null)
{
return;
}
// Not every UIDocument is in the tree already (because their root is null, for example), so we need
// to figure out the insertion point.
if (index > 0)
{
VisualElement previousInTree = null;
int i = 1;
while (previousInTree == null && index - i >= 0)
{
var previousUIDocument = m_AttachedUIDocuments[index - i++];
previousInTree = previousUIDocument.rootVisualElement;
}
if (previousInTree != null)
{
index = visualTree.IndexOf(previousInTree) + 1;
}
}
if (index > visualTree.childCount)
{
index = visualTree.childCount;
}
}
else
{
// Add in the end.
m_AttachedUIDocuments.Add(uiDocument);
}
if (visualTree == null || uiDocument.rootVisualElement == null)
{
return;
}
int insertionIndex = firstInsertIndex + index;
if (insertionIndex < visualTree.childCount)
{
visualTree.Insert(insertionIndex, uiDocument.rootVisualElement);
}
else
{
visualTree.Add(uiDocument.rootVisualElement);
}
}