// Does a deep extract of all top-level TextElements between two positions.
// Returns the combined symbol count of all extracted elements.
// Each extracted element (and its children) are moved into a private tree.
// This insures that outside references to the TextElement can still use
// the TextElements freely, inserting or removing content, etc.
//
// Also calls AddLogicalChild on any top-level UIElements encountered.
private int CutTopLevelLogicalNodes(TextTreeNode containingNode, TextPointer startPosition, TextPointer endPosition, out int charCount)
{
SplayTreeNode node;
SplayTreeNode nextNode;
SplayTreeNode stopNode;
TextTreeTextElementNode elementNode;
TextTreeObjectNode uiElementNode;
char[] elementText;
int symbolCount;
TextContainer tree;
TextPointer newTreeStart;
DependencyObject logicalParent;
object currentLogicalChild;
Invariant.Assert(startPosition.GetScopingNode() == endPosition.GetScopingNode(), "startPosition/endPosition not in same sibling tree!");
node = startPosition.GetAdjacentSiblingNode(LogicalDirection.Forward);
stopNode = endPosition.GetAdjacentSiblingNode(LogicalDirection.Forward);
symbolCount = 0;
charCount = 0;
logicalParent = containingNode.GetLogicalTreeNode();
while (node != stopNode)
{
currentLogicalChild = null;
// Get the next node now, before we extract any TextElementNodes.
nextNode = node.GetNextNode();
elementNode = node as TextTreeTextElementNode;
if (elementNode != null)
{
// Grab the IMECharCount before we modify the node.
// This value depends on the node's current context.
int imeCharCountInOriginalContainer = elementNode.IMECharCount;
// Cut and record the matching symbols.
elementText = TextTreeText.CutText(_rootNode.RootTextBlock, elementNode.GetSymbolOffset(this.Generation), elementNode.SymbolCount);
// Rip the element out of its sibling tree.
// textElementNode.TextElement's TextElementNode will be updated
// with a deep copy of all contained nodes. We need a deep copy
// to ensure the new element/tree has no TextPointer references.
ExtractElementFromSiblingTree(containingNode, elementNode, true /* deep */);
// Assert that the TextElement now points to a new TextElementNode, not the original one.
Invariant.Assert(elementNode.TextElement.TextElementNode != elementNode);
// We want to start referring to the copied node, update elementNode.
elementNode = elementNode.TextElement.TextElementNode;
UpdateContainerSymbolCount(containingNode, -elementNode.SymbolCount, -imeCharCountInOriginalContainer);
NextGeneration(true /* deletedContent */);
// Stick it in a private tree so it's safe for the outside world to play with.
tree = new TextContainer(null, false /* plainTextOnly */);
newTreeStart = tree.Start;
tree.InsertElementToSiblingTree(newTreeStart, newTreeStart, elementNode);
Invariant.Assert(elementText.Length == elementNode.SymbolCount);
tree.UpdateContainerSymbolCount(elementNode.GetContainingNode(), elementNode.SymbolCount, elementNode.IMECharCount);
tree.DemandCreateText();
TextTreeText.InsertText(tree.RootTextBlock, 1 /* symbolOffset */, elementText);
tree.NextGeneration(false /* deletedContent */);
currentLogicalChild = elementNode.TextElement;
// Keep a running total of how many symbols we've removed.
symbolCount += elementNode.SymbolCount;
charCount += imeCharCountInOriginalContainer;
}
else
{
uiElementNode = node as TextTreeObjectNode;
if (uiElementNode != null)
{
currentLogicalChild = uiElementNode.EmbeddedElement;
}
}
// Remove the child from the logical tree
LogicalTreeHelper.RemoveLogicalChild(logicalParent, currentLogicalChild);
node = nextNode;
}
if (symbolCount > 0)
{
startPosition.SyncToTreeGeneration();
endPosition.SyncToTreeGeneration();
}
return symbolCount;
}
