|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
// Description: Default Framework TextContainer implementation.
//
//#define DEBUG_SLOW
using System;
using System.Windows.Threading;
using MS.Internal;
using System.Collections;
using System.ComponentModel;
using System.Windows.Controls;
using System.Windows.Markup;
using MS.Internal.Documents;
using System.Windows.Data;
namespace System.Windows.Documents
{
/// <summary>
/// The TextContainer class is an implementation of the abstract TextContainer class,
/// the Framework's Text Object Model. It serves as a general purpose
/// backing store for text documents.
///
/// TextContainer accepts three kinds of content:
///
/// - Text. Raw characters/strings.
/// - UIElement controls.
/// - TextElements -- Inline, Paragraph, etc. These elements scope other
/// content and provide structural information and/or hold DependencyProperty
/// values.
///
/// References to content in the TextContainer are represented by TextPointer and
/// TextNavigator objects. Once allocated, TextPositions may never be modified;
/// TextNavigators may be repositioned and are the most efficent way to walk
/// the TextContainer content.
///
/// Listeners may attach delegates to the TextChanged event to receive a
/// notification whenever content is added, removed, or modified.
///
/// In addition to TextContainer overrides, TextContainer extends the Text Object Model
/// with a number of features:
///
/// - The TextContainer constructor takes an optional DependencyObject argument
/// used to inherit DependencyProperty values. If this argument is also
/// a FrameworkElement or FrameworkContentElement, it will parent all
/// top-level TextElements.
/// - Several methods are added that allow direct access to TextElement
/// instances.
///
/// </summary>
//
// INTERNAL COMMENTS.
//
// It's necessary understand the Avalon Text Object Model to follow the
// TextContainer implementation. There's a spec for the OM at
// http://avalon/uis/TextBox%20and%20RichTextBox/Text%20Object%20Model.doc.
//
// The TextContainer is implemented as a tree of trees. The outer tree follows
// the logical relationships between TextElements and their children. Each
// child collection is stored as an individual splay tree.
//
// For example,
//
// <Paragraph>Hi!</Paragraph><Paragraph>Fancy <Inline>text</Inline>.</Paragraph>
//
// becomes
//
// [TextTreeRootNode]
// ||
// [TextTreeTextElementNode]
// || \
// || \
// || \
// [TextTreeTextNode "Hi!"] [TextTreeTextElementNode]
// ||
// [TextTreeTextElementNode]
// / || \
// / || \
// / || \
// / || \
// / || \
// / || \
// [TextTreeTextNode "Fancy "] [TextTreeTextNode "text"] [TextTreeTextNode "."]
//
// "||" is a link from tree to tree, "|" is a link between nodes in a single tree.
//
// Nodes in the tree are one of
// - TextTreeRootNode. One per tree, always the top-level root. The
// root node is special because it holds tree global state, and because
// it can never be removed. Never has siblings, may contain other
// nodes.
//
// - TextTreeTextElementNode. Always maps to a single TextElement.
// Element nodes may contain other nodes.
//
// - TextTreeTextNode. References text. Never contains other nodes.
//
// - TextTreeObjectNode. Always maps to a single UIElement. Never
// contains other nodes.
//
// All nodes derive from the base TextTreeNode class.
//
// Raw text is stored in a separate tree of TextTreeTextBlocks. The static
// TextTreeText class handles all operations on the tree.
//
// TextPositions and TextNavigators are implemented in the TextPointer
// and TextTreeNavigators classes respectively.
internal class TextContainer : ITextContainer
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
/// <summary>
/// Creates a new TextContainer instance.
/// </summary>
/// <param name="parent">
/// A DependencyObject used to supply inherited property values for
/// TextElements contained within this TextContainer.
///
/// parent may be null.
///
/// If the object is FrameworkElement or FrameworkContentElement, it will be
/// the parent of all top-level TextElements.
/// </param>
/// <param name="plainTextOnly">
/// If true, only plain text may be inserted into this
/// TextContainer and perf optimizations are enabled.
/// </param>
internal TextContainer(DependencyObject parent, bool plainTextOnly)
{
_parent = parent;
SetFlags(plainTextOnly, Flags.PlainTextOnly);
}
#endregion Constructors
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
#region Public Methods
/// <summary>
/// Debug only ToString override.
/// </summary>
public override string ToString()
{
#if DEBUG
return ("TextContainer Id=" + _debugId + " SymbolCount=" + this.SymbolCount);
#else
return base.ToString();
#endif // DEBUG
}
#endregion Public Methods
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
// Allocates an UndoManager for this instance.
// This method should only be called once, but by controls
// that also creates TextEditors and want undo.
internal void EnableUndo(FrameworkElement uiScope)
{
Invariant.Assert(_undoManager == null, SR.TextContainer_UndoManagerCreatedMoreThanOnce);
_undoManager = new UndoManager();
MS.Internal.Documents.UndoManager.AttachUndoManager(uiScope, _undoManager);
}
internal void DisableUndo(FrameworkElement uiScope)
{
Invariant.Assert(_undoManager != null, "UndoManager not created.");
Invariant.Assert(_undoManager == MS.Internal.Documents.UndoManager.GetUndoManager(uiScope));
MS.Internal.Documents.UndoManager.DetachUndoManager(uiScope);
_undoManager = null;
}
/// <summary>
/// Sets a local value on the text element scoping position.
/// </summary>
/// <param name="position">
/// A position scoped by the element on which to set the property.
/// </param>
/// <param name="property">
/// Property to set.
/// </param>
/// <param name="value">
/// Value to set.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// Throws InvalidOperationException if position is not scoped by a
/// text element or if property may not be applied on the scoping text
/// element.
/// </exception>
internal void SetValue(TextPointer position, DependencyProperty property, object value)
{
TextElement textElement;
// VerifyAccess();
ArgumentNullException.ThrowIfNull(position);
ArgumentNullException.ThrowIfNull(property);
EmptyDeadPositionList();
ValidateSetValue(position);
BeginChange();
try
{
textElement = position.Parent as TextElement;
Invariant.Assert(textElement != null);
textElement.SetValue(property, value);
}
finally
{
EndChange();
}
}
/// <summary>
/// Sets local values on the text element scoping position.
/// </summary>
/// <param name="position">
/// A position scoped by the element on which to set the property.
/// </param>
/// <param name="values">
/// Values to set.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// Throws InvalidOperationException if position is not scoped by a
/// text element or if a property value may not be applied on the
/// scoping text element.
/// </exception>
internal void SetValues(TextPointer position, LocalValueEnumerator values)
{
TextElement textElement;
LocalValueEntry property;
// VerifyAccess();
ArgumentNullException.ThrowIfNull(position);
// LocalValueEnumerator is a struct.
// if (values == null)
// {
// throw new ArgumentNullException("values");
// }
EmptyDeadPositionList();
ValidateSetValue(position);
BeginChange();
try
{
textElement = position.Parent as TextElement;
Invariant.Assert(textElement != null);
values.Reset();
while (values.MoveNext())
{
property = values.Current;
// HUCK to word around a bug in property system.
// CachedSource property gets incorrect value in localValueEnumerator -
// object instead on HwndWindow. This causes crash in TextElement.SetValue.
// We actually don't need to transfer this property in this method,
// so the huck does not destory any functionality.
// More than that, we need to decide which properties are good to be
// copied this way. Actually we are interested in only formatting
// (serializable) properties. So we propably need to skip all other.
// However this bug needs a fix anyway.
if (property.Property.Name == "CachedSource")
{
continue;
}
// If the property is readonly on the text element, then we shouldn't
// try to copy the property value.
if (property.Property.ReadOnly)
{
continue;
}
// Don't copy over Run.Text. This will get automatically invalidated by TextContainer
// when the Run's text content is set. Setting this property now will cause TextContainer
// changes that get us into trouble in the middle of undo.
if (property.Property == Run.TextProperty)
{
continue;
}
BindingExpressionBase expr = property.Value as BindingExpressionBase;
if (expr != null)
{
// We can't duplicate a binding so copy over the current value instead.
textElement.SetValue(property.Property, expr.Value);
}
else
{
textElement.SetValue(property.Property, property.Value);
}
}
}
finally
{
EndChange();
}
}
internal void BeginChange()
{
BeginChange(true /* undo */);
}
internal void BeginChangeNoUndo()
{
BeginChange(false /* undo */);
}
/// <summary>
/// </summary>
internal void EndChange()
{
EndChange(false /* skipEvents */);
}
/// <summary>
/// </summary>
internal void EndChange(bool skipEvents)
{
TextContainerChangedEventArgs changes;
Invariant.Assert(_changeBlockLevel > 0, "Unmatched EndChange call!");
_changeBlockLevel--;
if (_changeBlockLevel == 0)
{
try
{
//
// Re-enable processing of the queue before the change notification.
//
_rootNode.DispatcherProcessingDisabled.Dispose();
//
// Raise the Changed event.
//
if (_changes != null)
{
changes = _changes;
_changes = null;
if (this.ChangedHandler != null && !skipEvents)
{
#if PROPERTY_CHANGES
changes.MergePropertyChanges();
#endif
ChangedHandler(this, changes);
}
}
}
finally
{
//
// Close the undo unit.
//
if (_changeBlockUndoRecord != null)
{
try
{
_changeBlockUndoRecord.OnEndChange();
}
finally
{
_changeBlockUndoRecord = null;
}
}
}
}
}
/// <summary>
/// </summary>
void ITextContainer.BeginChange()
{
BeginChange();
}
void ITextContainer.BeginChangeNoUndo()
{
BeginChangeNoUndo();
}
/// <summary>
/// </summary>
void ITextContainer.EndChange()
{
EndChange(false /* skipEvents */);
}
/// <summary>
/// </summary>
void ITextContainer.EndChange(bool skipEvents)
{
EndChange(skipEvents);
}
// Allocate a new ITextPointer at the specified offset.
// Equivalent to this.Start.CreatePointer(offset), but does not
// necessarily allocate this.Start.
ITextPointer ITextContainer.CreatePointerAtOffset(int offset, LogicalDirection direction)
{
return CreatePointerAtOffset(offset, direction);
}
// Allocate a new ITextPointer at the specified offset.
// Equivalent to this.Start.CreatePointer(offset), but does not
// necessarily allocate this.Start.
internal TextPointer CreatePointerAtOffset(int offset, LogicalDirection direction)
{
EmptyDeadPositionList();
DemandCreatePositionState();
return new TextPointer(this, offset + 1, direction);
}
// Allocate a new ITextPointer at a specificed offset in unicode chars within the document.
ITextPointer ITextContainer.CreatePointerAtCharOffset(int charOffset, LogicalDirection direction)
{
return CreatePointerAtCharOffset(charOffset, direction);
}
// Allocate a new ITextPointer at the specified character offset.
// Returns null if this.IMECharCount == 0 -- there are no char offsets.
// If a character offset has two possible mappings, for example
//
// <Run>abc</Run><Run>def</Run>
//
// character offset 3 could be at the end of the first Run or the start
// of the second -- then this method always returns the leftmost position
// (ie, end of the first Run).
internal TextPointer CreatePointerAtCharOffset(int charOffset, LogicalDirection direction)
{
EmptyDeadPositionList();
DemandCreatePositionState();
TextTreeNode node;
ElementEdge edge;
GetNodeAndEdgeAtCharOffset(charOffset, out node, out edge);
return (node == null) ? null : new TextPointer(this, node, edge, direction);
}
ITextPointer ITextContainer.CreateDynamicTextPointer(StaticTextPointer position, LogicalDirection direction)
{
return CreatePointerAtOffset(GetInternalOffset(position) - 1, direction);
}
internal StaticTextPointer CreateStaticPointerAtOffset(int offset)
{
SplayTreeNode node;
ElementEdge edge;
int nodeOffset;
EmptyDeadPositionList();
DemandCreatePositionState();
// Add +1 to offset because we're converting from external to internal offsets.
GetNodeAndEdgeAtOffset(offset + 1, false /* splitNode */, out node, out edge);
nodeOffset = (offset + 1) - node.GetSymbolOffset(this.Generation);
return new StaticTextPointer(this, node, nodeOffset);
}
StaticTextPointer ITextContainer.CreateStaticPointerAtOffset(int offset)
{
return CreateStaticPointerAtOffset(offset);
}
TextPointerContext ITextContainer.GetPointerContext(StaticTextPointer pointer, LogicalDirection direction)
{
TextTreeNode node = (TextTreeNode)pointer.Handle0;
int nodeOffset = pointer.Handle1;
TextPointerContext context;
ElementEdge edge;
if (node is TextTreeTextNode && nodeOffset > 0 && nodeOffset < node.SymbolCount)
{
context = TextPointerContext.Text;
}
else if (direction == LogicalDirection.Forward)
{
edge = node.GetEdgeFromOffset(nodeOffset, LogicalDirection.Forward);
context = TextPointer.GetPointerContextForward(node, edge);
}
else
{
edge = node.GetEdgeFromOffset(nodeOffset, LogicalDirection.Backward);
context = TextPointer.GetPointerContextBackward(node, edge);
}
return context;
}
// Returns the "internal" offset of a StaticTextPointer, which includes
// an extra symbol for the root node.
internal int GetInternalOffset(StaticTextPointer position)
{
TextTreeNode node = (TextTreeNode)position.Handle0;
int nodeOffset = position.Handle1;
int offset;
if (node is TextTreeTextNode)
{
offset = node.GetSymbolOffset(this.Generation) + nodeOffset;
}
else
{
offset = TextPointer.GetSymbolOffset(this, node, node.GetEdgeFromOffsetNoBias(nodeOffset));
}
return offset;
}
int ITextContainer.GetOffsetToPosition(StaticTextPointer position1, StaticTextPointer position2)
{
return GetInternalOffset(position2) - GetInternalOffset(position1);
}
int ITextContainer.GetTextInRun(StaticTextPointer position, LogicalDirection direction, char[] textBuffer, int startIndex, int count)
{
TextTreeNode node = (TextTreeNode)position.Handle0;
int nodeOffset = position.Handle1;
TextTreeTextNode textNode;
textNode = node as TextTreeTextNode;
if (textNode == null || nodeOffset == 0 || nodeOffset == node.SymbolCount)
{
textNode = TextPointer.GetAdjacentTextNodeSibling(node, node.GetEdgeFromOffsetNoBias(nodeOffset), direction);
nodeOffset = -1;
}
return textNode == null ? 0 : TextPointer.GetTextInRun(this, textNode.GetSymbolOffset(this.Generation), textNode, nodeOffset, direction, textBuffer, startIndex, count);
}
object ITextContainer.GetAdjacentElement(StaticTextPointer position, LogicalDirection direction)
{
TextTreeNode node = (TextTreeNode)position.Handle0;
int nodeOffset = position.Handle1;
DependencyObject adjacentElement;
if (node is TextTreeTextNode && nodeOffset > 0 && nodeOffset < node.SymbolCount)
{
adjacentElement = null;
}
else
{
adjacentElement = TextPointer.GetAdjacentElement(node, node.GetEdgeFromOffset(nodeOffset, direction), direction);
}
return adjacentElement;
}
private TextTreeNode GetScopingNode(StaticTextPointer position)
{
TextTreeNode node = (TextTreeNode)position.Handle0;
int nodeOffset = position.Handle1;
TextTreeNode scopingNode;
if (node is TextTreeTextNode && nodeOffset > 0 && nodeOffset < node.SymbolCount)
{
scopingNode = node;
}
else
{
scopingNode = TextPointer.GetScopingNode(node, node.GetEdgeFromOffsetNoBias(nodeOffset));
}
return scopingNode;
}
DependencyObject ITextContainer.GetParent(StaticTextPointer position)
{
return GetScopingNode(position).GetLogicalTreeNode();
}
StaticTextPointer ITextContainer.CreatePointer(StaticTextPointer position, int offset)
{
int positionOffset = GetInternalOffset(position) - 1; // -1 to convert to external offset.
return ((ITextContainer)this).CreateStaticPointerAtOffset(positionOffset + offset);
}
StaticTextPointer ITextContainer.GetNextContextPosition(StaticTextPointer position, LogicalDirection direction)
{
TextTreeNode node = (TextTreeNode)position.Handle0;
int nodeOffset = position.Handle1;
ElementEdge edge;
StaticTextPointer nextContextPosition;
bool moved;
if (node is TextTreeTextNode && nodeOffset > 0 && nodeOffset < node.SymbolCount)
{
// Jump to the edge of this run of text nodes.
if (this.PlainTextOnly)
{
// Instead of iterating through N text nodes, exploit
// the fact (when we can) that text nodes are only ever contained in
// runs with no other content. Jump straight to the end.
node = (TextTreeNode)node.GetContainingNode();
edge = (direction == LogicalDirection.Backward) ? ElementEdge.AfterStart : ElementEdge.BeforeEnd;
}
else
{
while (true)
{
TextTreeTextNode nextTextNode = ((direction == LogicalDirection.Forward) ? node.GetNextNode() : node.GetPreviousNode()) as TextTreeTextNode;
if (nextTextNode == null)
break;
node = nextTextNode;
}
edge = (direction == LogicalDirection.Backward) ? ElementEdge.BeforeStart : ElementEdge.AfterEnd;
}
moved = true;
}
else if (direction == LogicalDirection.Forward)
{
edge = node.GetEdgeFromOffset(nodeOffset, LogicalDirection.Forward);
moved = TextPointer.GetNextNodeAndEdge(node, edge, this.PlainTextOnly, out node, out edge);
}
else
{
edge = node.GetEdgeFromOffset(nodeOffset, LogicalDirection.Backward);
moved = TextPointer.GetPreviousNodeAndEdge(node, edge, this.PlainTextOnly, out node, out edge);
}
if (moved)
{
nextContextPosition = new StaticTextPointer(this, node, node.GetOffsetFromEdge(edge));
}
else
{
nextContextPosition = StaticTextPointer.Null;
}
return nextContextPosition;
}
int ITextContainer.CompareTo(StaticTextPointer position1, StaticTextPointer position2)
{
int offsetThis;
int offsetPosition;
int result;
offsetThis = GetInternalOffset(position1);
offsetPosition = GetInternalOffset(position2);
if (offsetThis < offsetPosition)
{
result = -1;
}
else if (offsetThis > offsetPosition)
{
result = +1;
}
else
{
result = 0;
}
return result;
}
int ITextContainer.CompareTo(StaticTextPointer position1, ITextPointer position2)
{
int offsetThis;
int offsetPosition;
int result;
offsetThis = GetInternalOffset(position1);
offsetPosition = position2.Offset + 1; // Convert to internal offset with +1.
if (offsetThis < offsetPosition)
{
result = -1;
}
else if (offsetThis > offsetPosition)
{
result = +1;
}
else
{
result = 0;
}
return result;
}
object ITextContainer.GetValue(StaticTextPointer position, DependencyProperty formattingProperty)
{
DependencyObject parent = GetScopingNode(position).GetDependencyParent();
return (parent == null) ? DependencyProperty.UnsetValue : parent.GetValue(formattingProperty);
}
// Prepares the tree for an AddChange call, and raises the Changing
// event if it has not already fired in this change block.
//
// This method must be called before a matching AddChange.
//
// (We cannot simply merge BeforeAddChange/AddChange because
// in practice callers will sometimes raise LogicalTree events which
// must be fired between Changing/Changed events.)
internal void BeforeAddChange()
{
Invariant.Assert(_changeBlockLevel > 0, "All public APIs must call BeginChange!");
if (this.HasListeners)
{
// Contact any listeners.
if (this.ChangingHandler != null)
{
ChangingHandler(this, EventArgs.Empty);
}
if (_changes == null)
{
_changes = new TextContainerChangedEventArgs();
}
}
}
// Adds a change to the current change block.
// This call must be preceeded by a matching BeforeAddChange.
internal void AddChange(TextPointer startPosition, int symbolCount, int charCount, PrecursorTextChangeType textChange)
{
AddChange(startPosition, symbolCount, charCount, textChange, null, false);
}
// Adds a change to the current change block.
// This call must be preceeded by a matching BeforeAddChange.
internal void AddChange(TextPointer startPosition, int symbolCount, int charCount, PrecursorTextChangeType textChange, DependencyProperty property, bool affectsRenderOnly)
{
Invariant.Assert(textChange != PrecursorTextChangeType.ElementAdded &&
textChange != PrecursorTextChangeType.ElementExtracted,
"Need second TextPointer for ElementAdded/Extracted operations!");
AddChange(startPosition, null, symbolCount, /* leftEdgeCharCount */ 0, charCount, textChange, property, affectsRenderOnly);
}
// Adds a change to the current change block.
// This call must be preceeded by a matching BeforeAddChange.
internal void AddChange(TextPointer startPosition, TextPointer endPosition,
int symbolCount, int leftEdgeCharCount, int childCharCount,
PrecursorTextChangeType textChange, DependencyProperty property, bool affectsRenderOnly)
{
Invariant.Assert(_changeBlockLevel > 0, "All public APIs must call BeginChange!");
Invariant.Assert(!CheckFlags(Flags.ReadOnly) ||
textChange == PrecursorTextChangeType.PropertyModified,
"Illegal to modify TextContainer structure inside Change event scope!");
if (this.HasListeners)
{
// Lazy init _changes. This looks redundant with the BeforeAddChange call
// we already require -- strictly speaking that's true. But in practice,
// we want the Invariant in this method to remind callers to think about
// when they must call BeforeAddChange ahead of logical tree events. Then,
// in practice, there's a subtle bug where a listener might not initially
// exist but is added during the logical tree events. That we handle
// here with an additional BeforeAddChange call instead of requiring all
// our callers to remember to handle the more subtle case.
if (_changes == null)
{
_changes = new TextContainerChangedEventArgs();
}
Invariant.Assert(_changes != null, "Missing call to BeforeAddChange!");
_changes.AddChange(textChange, startPosition.Offset, symbolCount, this.CollectTextChanges);
if (this.ChangeHandler != null)
{
FireChangeEvent(startPosition, endPosition, symbolCount, leftEdgeCharCount, childCharCount, textChange, property, affectsRenderOnly);
}
}
}
// Set the bit on the current change collection that remembers that
// a local property value has changed on a TextElement covered by
// the collection.
internal void AddLocalValueChange()
{
Invariant.Assert(_changeBlockLevel > 0, "All public APIs must call BeginChange!");
_changes.SetLocalPropertyValueChanged();
}
// The InsertText worker. Adds text to the tree at a specified position.
// text is either a string or char[] to insert.
internal void InsertTextInternal(TextPointer position, object text)
{
TextTreeTextNode textNode;
SplayTreeNode containingNode;
TextPointer originalPosition;
int symbolOffset;
int textLength;
LogicalDirection direction;
Invariant.Assert(text is string || text is char[], "Unexpected type for 'text' parameter!");
textLength = GetTextLength(text);
if (textLength == 0)
return;
DemandCreateText();
position.SyncToTreeGeneration();
if (Invariant.Strict)
{
if (position.Node.SymbolCount == 0)
{
// We expect only TextTreeTextNodes ever have zero symbol counts.
// This can happen in two cases:
//
// <TextNode referencedEdge=BeforeStart symbolCount=1+/> <TextNode referencedEdge=AfterEnd symbolCount=0/>
// or
// <TextNode referencedEdge=BeforeStart symbolCount=0/> <TextNode referencedEdge=AfterEnd symbolCount=1+/>
//
Invariant.Assert(position.Node is TextTreeTextNode);
Invariant.Assert((position.Edge == ElementEdge.AfterEnd && position.Node.GetPreviousNode() is TextTreeTextNode && position.Node.GetPreviousNode().SymbolCount > 0) ||
(position.Edge == ElementEdge.BeforeStart && position.Node.GetNextNode() is TextTreeTextNode && position.Node.GetNextNode().SymbolCount > 0));
}
}
BeforeAddChange();
// During document load we won't have listeners and we can save
// an allocation on every insert. This can easily save 1000's of allocations during boot.
originalPosition = this.HasListeners ? new TextPointer(position, LogicalDirection.Backward) : null;
// Find a bordering TextTreeTextNode, if any.
// We know position already points to the current TextNode, if there is one, so
// we can't append text to that node (it would disrespect position's gravity to do so).
// So we either have to find a neighboring text node with no position references, or
// create a new node.
// Look for a bordering text node.
if (position.Edge == ElementEdge.BeforeStart || position.Edge == ElementEdge.BeforeEnd)
{
direction = LogicalDirection.Backward;
}
else
{
direction = LogicalDirection.Forward;
}
textNode = position.GetAdjacentTextNodeSibling(direction);
if (textNode != null)
{
// We can't use a text node that is already referred to by text positions.
// Doing so could displace the positions, since they expect to remain at
// the node edge no matter what happens.
if ((direction == LogicalDirection.Backward && textNode.AfterEndReferenceCount) ||
(direction == LogicalDirection.Forward && textNode.BeforeStartReferenceCount))
{
textNode = null;
}
}
if (textNode == null)
{
// No text node available. Create and insert one.
textNode = new TextTreeTextNode();
textNode.InsertAtPosition(position);
containingNode = textNode.GetContainingNode();
}
else
{
// We didn't insert a new node, so splay textNode to the root so
// we don't invalidate any LeftSymbolCounts of ancestor nodes.
textNode.Splay();
containingNode = textNode.ParentNode;
}
// Update the symbol counts.
textNode.SymbolCount += textLength; // This simultaneously updates textNode.IMECharCount.
UpdateContainerSymbolCount(containingNode, /* symbolCount */ textLength, /* charCount */ textLength);
// Insert the raw text.
symbolOffset = textNode.GetSymbolOffset(this.Generation);
TextTreeText.InsertText(_rootNode.RootTextBlock, symbolOffset, text);
// Handle undo.
TextTreeUndo.CreateInsertUndoUnit(this, symbolOffset, textLength);
// Announce the change.
NextGeneration(false /* deletedContent */);
AddChange(originalPosition, /* symbolCount */ textLength, /* charCount */ textLength, PrecursorTextChangeType.ContentAdded);
// Notify the TextElement of a content change.
TextElement textElement = position.Parent as TextElement;
if (textElement != null)
{
textElement.OnTextUpdated();
}
}
// InsertElement worker. Adds a TextElement to the tree.
// If element is already in a tree, we remove it, do a deep copy of its content,
// and insert that too.
internal void InsertElementInternal(TextPointer startPosition, TextPointer endPosition, TextElement element)
{
TextTreeTextElementNode elementNode;
int symbolOffset;
int childSymbolCount;
TextPointer startEdgePosition;
TextPointer endEdgePosition;
char[] elementText;
ExtractChangeEventArgs extractChangeEventArgs;
DependencyObject parentLogicalNode;
bool newElementNode;
int deltaCharCount;
Invariant.Assert(!this.PlainTextOnly);
Invariant.Assert(startPosition.TextContainer == this);
Invariant.Assert(endPosition.TextContainer == this);
DemandCreateText();
startPosition.SyncToTreeGeneration();
endPosition.SyncToTreeGeneration();
bool scopesExistingContent = startPosition.CompareTo(endPosition) != 0;
BeforeAddChange();
// Remove element from any previous tree.
// When called from a public method we already checked all the
// illegal cases in CanInsertElementInternal.
if (element.TextElementNode != null)
{
// This element is already in a tree. Remove it!
bool sameTextContainer = (this == element.TextContainer);
if (!sameTextContainer)
{
// This is a cross-tree extract.
// We need to start a change block now, so that we can
// raise a Changing event inside ExtractElementInternal
// before raising the LogicalTree events below.
// We'll make an EndChange call to wrap up below.
element.TextContainer.BeginChange();
}
bool exceptionThrown = true;
try
{
// ExtractElementInternal will raise LogicalTree events which
// could raise exceptions from external code.
elementText = element.TextContainer.ExtractElementInternal(element, true /* deep */, out extractChangeEventArgs);
exceptionThrown = false;
}
finally
{
if (exceptionThrown && !sameTextContainer)
{
// If an exception is thrown, make sure we close the
// change block we opened above before unwinding.
element.TextContainer.EndChange();
}
}
elementNode = element.TextElementNode;
deltaCharCount = extractChangeEventArgs.ChildIMECharCount;
if (sameTextContainer)
{
// Re-sync the TextPointers in case we just extracted from this tree.
startPosition.SyncToTreeGeneration();
endPosition.SyncToTreeGeneration();
// We must add the extract change now, before we move on to the insert.
// (When !sameTextContainer we want to delay the notification in the extract
// tree until the insert tree is in an accessible state, ie at the end of this method.)
extractChangeEventArgs.AddChange();
// Don't re-raise the change below.
extractChangeEventArgs = null;
}
newElementNode = false;
}
else
{
// Allocate a node in the tree to hold the element.
elementText = null;
elementNode = new TextTreeTextElementNode();
deltaCharCount = 0;
newElementNode = true;
extractChangeEventArgs = null;
}
parentLogicalNode = startPosition.GetLogicalTreeNode();
// Invalidate any TextElementCollection that depends on the parent.
// Make sure we do that before raising any public events.
TextElementCollectionHelper.MarkDirty(parentLogicalNode);
// Link the TextElement to the TextElementNode.
if (newElementNode)
{
elementNode.TextElement = element;
element.TextElementNode = (TextTreeTextElementNode)elementNode;
}
// If the new element will become the parent of an old element,
// the old element may become a firstIMEVisibleSibling.
TextTreeTextElementNode newFirstIMEVisibleNode = null;
int newFirstIMEVisibleNodeCharDelta = 0;
if (scopesExistingContent)
{
newFirstIMEVisibleNode = startPosition.GetAdjacentTextElementNodeSibling(LogicalDirection.Forward);
if (newFirstIMEVisibleNode != null)
{
newFirstIMEVisibleNodeCharDelta = -newFirstIMEVisibleNode.IMELeftEdgeCharCount;
newFirstIMEVisibleNode.IMECharCount += newFirstIMEVisibleNodeCharDelta;
}
}
// Attach the element node.
childSymbolCount = InsertElementToSiblingTree(startPosition, endPosition, elementNode);
// Add the edge char count to our delta. We couldn't get this before
// because it depends on the position of the element in the tree.
deltaCharCount += elementNode.IMELeftEdgeCharCount;
TextTreeTextElementNode formerFirstIMEVisibleNode = null;
int formerFirstIMEVisibleNodeCharDelta = 0;
if (element.IsFirstIMEVisibleSibling && !scopesExistingContent)
{
formerFirstIMEVisibleNode = (TextTreeTextElementNode)elementNode.GetNextNode();
if (formerFirstIMEVisibleNode != null)
{
// The following node was the former first ime visible sibling.
// It just moved, and gains an edge character.
formerFirstIMEVisibleNodeCharDelta = formerFirstIMEVisibleNode.IMELeftEdgeCharCount;
formerFirstIMEVisibleNode.IMECharCount += formerFirstIMEVisibleNodeCharDelta;
}
}
// Ancester nodes gain the two edge symbols.
UpdateContainerSymbolCount(elementNode.GetContainingNode(), /* symbolCount */ elementText == null ? 2 : elementText.Length, deltaCharCount + formerFirstIMEVisibleNodeCharDelta + newFirstIMEVisibleNodeCharDelta);
symbolOffset = elementNode.GetSymbolOffset(this.Generation);
if (newElementNode)
{
// Insert text to account for the element edges.
TextTreeText.InsertElementEdges(_rootNode.RootTextBlock, symbolOffset, childSymbolCount);
}
else
{
// element already has an existing child, just copy over the corresponding text.
TextTreeText.InsertText(_rootNode.RootTextBlock, symbolOffset, elementText);
}
NextGeneration(false /* deletedContent */);
// Handle undo.
TextTreeUndo.CreateInsertElementUndoUnit(this, symbolOffset, elementText != null /* deep */);
// If we extracted the TextElement from another tree, raise that event now.
// We can't raise this event any earlier, because prior to now _this_ tree
// is in an invalid state and this tree could be referenced by a listener
// to changes on the other tree.
if (extractChangeEventArgs != null)
{
// Announce the extract from the old tree.
// NB: we already Removed the element from the original logical tree with LogicalTreeHelper,
// and did a BeginChange above.
extractChangeEventArgs.AddChange();
extractChangeEventArgs.TextContainer.EndChange();
}
// Raise the public event for the insert into this tree.
// During document load we won't have listeners and we can save
// an allocation on every insert. This can easily save 1000's of allocations during boot.
if (this.HasListeners)
{
// REVIEW:benwest: this is a great place to use StaticTextPointer to eliminate allocations.
startEdgePosition = new TextPointer(this, elementNode, ElementEdge.BeforeStart);
if (childSymbolCount == 0 || elementText != null)
{
AddChange(startEdgePosition, elementText == null ? 2 : elementText.Length, deltaCharCount, PrecursorTextChangeType.ContentAdded);
}
else
{
endEdgePosition = new TextPointer(this, elementNode, ElementEdge.BeforeEnd);
AddChange(startEdgePosition, endEdgePosition, elementNode.SymbolCount,
elementNode.IMELeftEdgeCharCount, elementNode.IMECharCount - elementNode.IMELeftEdgeCharCount,
PrecursorTextChangeType.ElementAdded, null, false);
}
if (formerFirstIMEVisibleNodeCharDelta != 0)
{
RaiseEventForFormerFirstIMEVisibleNode(formerFirstIMEVisibleNode);
}
if (newFirstIMEVisibleNodeCharDelta != 0)
{
RaiseEventForNewFirstIMEVisibleNode(newFirstIMEVisibleNode);
}
}
// Insert the element into a Framework logical tree
element.BeforeLogicalTreeChange();
try
{
LogicalTreeHelper.AddLogicalChild(parentLogicalNode, element);
}
finally
{
element.AfterLogicalTreeChange();
}
// Reparent all children.
// We only need to do this if we created a new element node.
if (newElementNode)
{
ReparentLogicalChildren(elementNode, elementNode.TextElement, parentLogicalNode /* oldParent */);
}
// Notify the TextElement of a content change if it was moved to parent new content. This
// can happen when Runs get merged.
if (scopesExistingContent)
{
element.OnTextUpdated();
}
}
// InsertEmbeddedObject worker. Adds a UIElement to the tree.
internal void InsertEmbeddedObjectInternal(TextPointer position, DependencyObject embeddedObject)
{
TextTreeNode objectNode;
int symbolOffset;
DependencyObject parentLogicalNode;
TextPointer insertPosition;
Invariant.Assert(!this.PlainTextOnly);
DemandCreateText();
position.SyncToTreeGeneration();
BeforeAddChange();
parentLogicalNode = position.GetLogicalTreeNode();
// Insert a node.
objectNode = new TextTreeObjectNode(embeddedObject);
objectNode.InsertAtPosition(position);
// Update the symbol count.
UpdateContainerSymbolCount(objectNode.GetContainingNode(), objectNode.SymbolCount, objectNode.IMECharCount);
// Insert the corresponding text.
symbolOffset = objectNode.GetSymbolOffset(this.Generation);
TextTreeText.InsertObject(_rootNode.RootTextBlock, symbolOffset);
NextGeneration(false /* deletedContent */);
// Handle undo.
TextTreeUndo.CreateInsertUndoUnit(this, symbolOffset, 1);
// Tell parent to update Logical Tree
LogicalTreeHelper.AddLogicalChild(parentLogicalNode, embeddedObject);
// Raise the public event.
// During document load we won't have listeners and we can save
// an allocation on every insert. This can easily save 1000's of allocations during boot.
if (this.HasListeners)
{
insertPosition = new TextPointer(this, objectNode, ElementEdge.BeforeStart);
AddChange(insertPosition, 1, 1, PrecursorTextChangeType.ContentAdded);
}
}
// DeleteContent worker. Removes content from the tree.
internal void DeleteContentInternal(TextPointer startPosition, TextPointer endPosition)
{
TextTreeNode containingNode;
int symbolCount;
int charCount;
TextTreeUndoUnit undoUnit;
TextPointer deletePosition;
startPosition.SyncToTreeGeneration();
endPosition.SyncToTreeGeneration();
if (startPosition.CompareTo(endPosition) == 0)
return;
BeforeAddChange();
undoUnit = TextTreeUndo.CreateDeleteContentUndoUnit(this, startPosition, endPosition);
containingNode = startPosition.GetScopingNode();
// Invalidate any TextElementCollection that depends on the parent.
// Make sure we do that before raising any public events.
TextElementCollectionHelper.MarkDirty(containingNode.GetLogicalTreeNode());
int nextIMEVisibleNodeCharDelta = 0;
TextTreeTextElementNode nextIMEVisibleNode = GetNextIMEVisibleNode(startPosition, endPosition);
if (nextIMEVisibleNode != null)
{
// The node following the delete just became the first sibling.
// This might affect its ime char count.
nextIMEVisibleNodeCharDelta = -nextIMEVisibleNode.IMELeftEdgeCharCount;
nextIMEVisibleNode.IMECharCount += nextIMEVisibleNodeCharDelta;
}
// First cut: remove all top-level TextElements and their chilren.
// We need to put each TextElement in its own tree, so that any outside
// references can still play with the TextElements safely.
symbolCount = CutTopLevelLogicalNodes(containingNode, startPosition, endPosition, out charCount);
// Cut what's left.
int remainingCharCount;
symbolCount += DeleteContentFromSiblingTree(containingNode, startPosition, endPosition, nextIMEVisibleNodeCharDelta != 0, out remainingCharCount);
charCount += remainingCharCount;
Invariant.Assert(symbolCount > 0);
if (undoUnit != null)
{
undoUnit.SetTreeHashCode();
}
// Public tree event.
deletePosition = new TextPointer(startPosition, LogicalDirection.Forward);
AddChange(deletePosition, symbolCount, charCount, PrecursorTextChangeType.ContentRemoved);
if (nextIMEVisibleNodeCharDelta != 0)
{
RaiseEventForNewFirstIMEVisibleNode(nextIMEVisibleNode);
}
}
internal void GetNodeAndEdgeAtOffset(int offset, out SplayTreeNode node, out ElementEdge edge)
{
GetNodeAndEdgeAtOffset(offset, true /* splitNode */, out node, out edge);
}
// Finds a node/edge pair matching a given symbol offset in the tree.
// If the pair matches a character within a text node, the text node is split.
internal void GetNodeAndEdgeAtOffset(int offset, bool splitNode, out SplayTreeNode node, out ElementEdge edge)
{
int nodeOffset;
int siblingTreeOffset;
bool checkZeroWidthNode;
// Offset zero/SymbolCount-1 are before/after the root node, which
// is an illegal position -- you can't add or remove content there
// and it's never exposed publicly.
Invariant.Assert(offset >= 1 && offset <= this.InternalSymbolCount - 1, "Bogus symbol offset!");
// If this flag is set true on exit, we need to consider the case
// where we've found a "zero-width" (SymbolCount == 0) text node.
// Zero width nodes needs special handling, since they are logically
// part of a following or preceding node.
checkZeroWidthNode = false;
// Find the node.
node = _rootNode;
nodeOffset = 0;
// Each iteration walks through one tree.
while (true)
{
// While we're at it, fix up the node's SymbolOffsetCache,
// since we're doing the work already.
Invariant.Assert(node.Generation != _rootNode.Generation ||
node.SymbolOffsetCache == -1 ||
node.SymbolOffsetCache == nodeOffset, "Bad node offset cache!");
node.Generation = _rootNode.Generation;
node.SymbolOffsetCache = nodeOffset;
if (offset == nodeOffset)
{
edge = ElementEdge.BeforeStart;
checkZeroWidthNode = true;
break;
}
if (node is TextTreeRootNode || node is TextTreeTextElementNode)
{
if (offset == nodeOffset + 1)
{
edge = ElementEdge.AfterStart;
break;
}
if (offset == nodeOffset + node.SymbolCount - 1)
{
edge = ElementEdge.BeforeEnd;
break;
}
}
if (offset == nodeOffset + node.SymbolCount)
{
edge = ElementEdge.AfterEnd;
checkZeroWidthNode = true;
break;
}
// No child node? That means we're inside a TextTreeTextNode.
if (node.ContainedNode == null)
{
Invariant.Assert(node is TextTreeTextNode);
// Need to split the TextTreeTextNode.
// Here we want a character buried inside a single node, split
// the node open....
if (splitNode)
{
node = ((TextTreeTextNode)node).Split(offset - nodeOffset, ElementEdge.AfterEnd);
}
edge = ElementEdge.BeforeStart;
break;
}
// Need to look into one of the child nodes.
node = node.ContainedNode;
nodeOffset += 1; // Skip over the parent element start edge.
// Walk down the sibling tree.
node = node.GetSiblingAtOffset(offset - nodeOffset, out siblingTreeOffset);
nodeOffset += siblingTreeOffset;
}
// If we're on a zero-width TextTreeTextNode we need some special handling.
if (checkZeroWidthNode)
{
node = AdjustForZeroWidthNode(node, edge);
}
}
// Finds a node/edge pair matching a given char offset in the tree.
// If the pair matches a character within a text node, the text node is split.
internal void GetNodeAndEdgeAtCharOffset(int charOffset, out TextTreeNode node, out ElementEdge edge)
{
int nodeCharOffset;
int siblingTreeCharOffset;
bool checkZeroWidthNode;
// Offset zero/SymbolCount-1 are before/after the root node, which
// is an illegal position -- you can't add or remove content there
// and it's never exposed publicly.
Invariant.Assert(charOffset >= 0 && charOffset <= this.IMECharCount, "Bogus char offset!");
if (this.IMECharCount == 0)
{
node = null;
edge = ElementEdge.BeforeStart;
return;
}
// If this flag is set true on exit, we need to consider the case
// where we've found a "zero-width" (SymbolCount == 0) text node.
// Zero width nodes needs special handling, since they are logically
// part of a following or preceding node.
checkZeroWidthNode = false;
// Find the node.
node = _rootNode;
nodeCharOffset = 0;
// Each iteration walks through one tree.
while (true)
{
int leftEdgeCharCount = 0;
TextTreeTextElementNode textElementNode = node as TextTreeTextElementNode;
if (textElementNode != null)
{
leftEdgeCharCount = textElementNode.IMELeftEdgeCharCount;
if (leftEdgeCharCount > 0)
{
if (charOffset == nodeCharOffset)
{
edge = ElementEdge.BeforeStart;
break;
}
if (charOffset == nodeCharOffset + leftEdgeCharCount)
{
edge = ElementEdge.AfterStart;
break;
}
}
}
else if (node is TextTreeTextNode || node is TextTreeObjectNode)
{
if (charOffset == nodeCharOffset)
{
edge = ElementEdge.BeforeStart;
checkZeroWidthNode = true;
break;
}
if (charOffset == nodeCharOffset + node.IMECharCount)
{
edge = ElementEdge.AfterEnd;
checkZeroWidthNode = true;
break;
}
}
// No child node? That means we're inside a TextTreeTextNode.
if (node.ContainedNode == null)
{
Invariant.Assert(node is TextTreeTextNode);
// Need to split the TextTreeTextNode.
// Here we want a character buried inside a single node, split
// the node open....
node = ((TextTreeTextNode)node).Split(charOffset - nodeCharOffset, ElementEdge.AfterEnd);
edge = ElementEdge.BeforeStart;
break;
}
// Need to look into one of the child nodes.
node = (TextTreeNode)node.ContainedNode;
nodeCharOffset += leftEdgeCharCount; // Skip over the parent element start edge.
// Walk down the sibling tree.
node = (TextTreeNode)node.GetSiblingAtCharOffset(charOffset - nodeCharOffset, out siblingTreeCharOffset);
nodeCharOffset += siblingTreeCharOffset;
}
// If we're on a zero-width TextTreeTextNode we need some special handling.
if (checkZeroWidthNode)
{
node = (TextTreeNode)AdjustForZeroWidthNode(node, edge);
}
}
// This method checks for any finalized positions and, if found, decrements
// their nodes' reference counts before finally releasing the positions
// into the void. See TextPointer for an explanation
// of the entire process.
//
// Called from all public entry points.
internal void EmptyDeadPositionList()
{
#if REFCOUNT_DEAD_TEXTPOINTERS
TextPointer[] localList;
TextPointer position;
ArrayList deadPositionList;
int i;
if (_rootNode == null)
return; // No TextPositions allocated yet.
deadPositionList = _rootNode.DeadPositionList;
localList = null;
// We need to lock deadPositionList before accessing it because
// it is also referenced by the finalizer thread.
// We hold it just long enough to make a copy and clear it.
//
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// NB: This lock will occasionally cause reentrancy.
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// See PS Task Item 14229: there's a general problem where any CLR
// lock will rev up a message pump if blocked. The Core team is
// expecting a CLR drop in 3.3 that will enable us to change this
// behavior, within Avalon. benwest:3/31/2004.
lock (deadPositionList)
{
if (deadPositionList.Count > 0)
{
localList = new TextPointer[deadPositionList.Count];
deadPositionList.CopyTo(localList);
deadPositionList.Clear();
}
}
// Now go through the thread safe copy and decrement reference
// counts. Ultimately this will merge text nodes that have been
// split by positions.
if (localList != null)
{
for (i = 0; i < localList.Length; i++)
{
position = localList[i];
position.SyncToTreeGeneration();
position.Node.DecrementReferenceCount(position.Edge);
}
}
#endif // REFCOUNT_DEAD_TEXTPOINTERS
}
// Returns the lenth of a text object. Text objects are always either
// strings or char arrays.
internal static int GetTextLength(object text)
{
string textString;
int length;
Invariant.Assert(text is string || text is char[], "Bad text parameter!");
textString = text as string;
if (textString != null)
{
length = textString.Length;
}
else
{
length = ((char[])text).Length;
}
return length;
}
internal void AssertTree()
{
#if DEBUG_SLOW
if (_rootNode != null && _rootNode.ContainedNode != null)
{
AssertTreeRecursive(_rootNode);
}
#endif // DEBUG_SLOW
}
// Returns a hash code identifying the current content state.
// Used to flag errors in the undo code.
internal int GetContentHashCode()
{
return this.InternalSymbolCount;
}
// Increments the tree's layout generation counter.
// This happens whenever a layout related property value
// changes on a TextElement.
internal void NextLayoutGeneration()
{
_rootNode.LayoutGeneration++;
}
// Removes a TextElement from the tree.
// Any TextElement content is left in the tree.
internal void ExtractElementInternal(TextElement element)
{
ExtractChangeEventArgs extractChangeEventArgs;
ExtractElementInternal(element, false /* deep */, out extractChangeEventArgs);
}
// Wrapper for this.TextView.IsAtCaretUnitBoundary, adds a cache.
internal bool IsAtCaretUnitBoundary(TextPointer position)
{
position.DebugAssertGeneration();
Invariant.Assert(position.HasValidLayout);
if (_rootNode.CaretUnitBoundaryCacheOffset != position.GetSymbolOffset())
{
_rootNode.CaretUnitBoundaryCacheOffset = position.GetSymbolOffset();
_rootNode.CaretUnitBoundaryCache = _textview.IsAtCaretUnitBoundary(position);
if (!_rootNode.CaretUnitBoundaryCache && position.LogicalDirection == LogicalDirection.Backward)
{
// In MIL Text and TextView worlds, a position at trailing edge of a newline (with backward gravity)
// is not an allowed caret stop.
// However, in TextPointer world we must allow such a position to be a valid insertion position,
// since it breaks textrange normalization for empty ranges.
// Hence, we need to check for TextView.IsAtCaretUnitBoundary in reverse direction here.
TextPointer positionForwardGravity = position.GetPositionAtOffset(0, LogicalDirection.Forward);
_rootNode.CaretUnitBoundaryCache = _textview.IsAtCaretUnitBoundary(positionForwardGravity);
}
}
return _rootNode.CaretUnitBoundaryCache;
}
#endregion Internal Methods
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
#region Internal Properties
/// <summary>
/// A position preceding the first symbol of this TextContainer.
/// </summary>
/// <remarks>
/// The returned TextPointer has LogicalDirection.Backward gravity.
/// </remarks>
internal TextPointer Start
{
get
{
TextPointer startPosition;
// VerifyAccess();
EmptyDeadPositionList();
DemandCreatePositionState();
startPosition = new TextPointer(this, _rootNode, ElementEdge.AfterStart, LogicalDirection.Backward);
startPosition.Freeze();
#if REFCOUNT_DEAD_TEXTPOINTERS
// Since start/end position are always on the root node, and the
// root node can never be removed, we don't need to ref count it
// and therefore we don't need to run the TextPointer finalizer.
GC.SuppressFinalize(startPosition);
#endif // REFCOUNT_DEAD_TEXTPOINTERS
return startPosition;
}
}
/// <summary>
/// A position following the last symbol of this TextContainer.
/// </summary>
/// <remarks>
/// The returned TextPointer has LogicalDirection.Forward gravity.
/// </remarks>
internal TextPointer End
{
get
{
TextPointer endPosition;
// VerifyAccess();
EmptyDeadPositionList();
DemandCreatePositionState();
endPosition = new TextPointer(this, _rootNode, ElementEdge.BeforeEnd, LogicalDirection.Forward);
endPosition.Freeze();
#if REFCOUNT_DEAD_TEXTPOINTERS
// Since start/end position are always on the root node, and the
// root node can never be removed, we don't need to ref count it
// and therefore we don't need to run the TextPointer finalizer.
GC.SuppressFinalize(endPosition);
#endif // REFCOUNT_DEAD_TEXTPOINTERS
return endPosition;
}
}
/// <summary>
/// An object from which property values are inherited.
/// </summary>
/// <remarks>
/// May be null.
/// </remarks>
internal DependencyObject Parent
{
get
{
// VerifyAccess();
return _parent;
}
}
bool ITextContainer.IsReadOnly
{
get
{
return CheckFlags(Flags.ReadOnly);
}
}
ITextPointer ITextContainer.Start
{
get
{
return this.Start;
}
}
ITextPointer ITextContainer.End
{
get
{
return this.End;
}
}
// The tree generation. Incremented whenever the tree content changes.
// Use NextGeneration to increment the generation.
uint ITextContainer.Generation
{
get
{
return this.Generation;
}
}
Highlights ITextContainer.Highlights
{
get
{
return this.Highlights;
}
}
DependencyObject ITextContainer.Parent
{
get
{
return this.Parent;
}
}
// TextEditor owns setting and clearing this property inside its
// ctor/OnDetach methods.
ITextSelection ITextContainer.TextSelection
{
get
{
return this.TextSelection;
}
set
{
_textSelection = value;
}
}
// Optional undo manager, may be null.
UndoManager ITextContainer.UndoManager
{
get
{
return this.UndoManager;
}
}
// <see cref="System.Windows.Documents.ITextContainer/>
ITextView ITextContainer.TextView
{
get
{
return this.TextView;
}
set
{
this.TextView = value;
}
}
// <see cref="System.Windows.Documents.ITextContainer/>
internal ITextView TextView
{
get
{
return _textview;
}
set
{
_textview = value;
}
}
// Count of symbols in this tree, equivalent to this.Start.GetOffsetToPosition(this.End),
// but doesn't necessarily allocate anything.
int ITextContainer.SymbolCount
{
get
{
return this.SymbolCount;
}
}
// Count of symbols in this tree, equivalent to this.Start.GetOffsetToPosition(this.End),
// but doesn't necessarily allocate anything.
internal int SymbolCount
{
get
{
// ITextContainer symbol count does not include the root node,
// so subtract 2 symbols.
return this.InternalSymbolCount - 2;
}
}
// The symbol count for the entire tree. This includes the private
// root node, which has 2 symbols, one for each edge.
internal int InternalSymbolCount
{
get
{
return (_rootNode == null ? 2 : _rootNode.SymbolCount);
}
}
// Character count for the entire tree.
internal int IMECharCount
{
get
{
return (_rootNode == null ? 0 : _rootNode.IMECharCount);
}
}
// Character count for the entire tree.
int ITextContainer.IMECharCount
{
get
{
return this.IMECharCount;
}
}
// A tree of TextTreeTextBlocks, used to store raw text.
// Callers must use DemandCreateText before accessing this property.
internal TextTreeRootTextBlock RootTextBlock
{
get
{
Invariant.Assert(_rootNode != null, "Asking for TextBlocks before root node create!");
return _rootNode.RootTextBlock;
}
}
// The tree generation. Incremented whenever the tree content changes.
// Use NextGeneration to increment the generation.
internal uint Generation
{
get
{
// It shouldn't be possible to modify the tree before allocating
// a TextPointer...which creates the root node.
Invariant.Assert(_rootNode != null, "Asking for Generation before root node create!");
return _rootNode.Generation;
}
}
// Like Generation, but only updated when a change could affect positions.
// Positions only need to synchronize after deletes, inserts are harmless.
internal uint PositionGeneration
{
get
{
Invariant.Assert(_rootNode != null, "Asking for PositionGeneration before root node create!");
return _rootNode.PositionGeneration;
}
}
// Like Generation, but incremented on each layout related property change
// to a TextElement in the tree.
internal uint LayoutGeneration
{
get
{
Invariant.Assert(_rootNode != null, "Asking for LayoutGeneration before root node create!");
return _rootNode.LayoutGeneration;
}
}
#if REFCOUNT_DEAD_TEXTPOINTERS
// A list of positions ready to be garbage collected. The TextPointer
// finalizer adds positions to this list.
internal ArrayList DeadPositionList
{
get
{
// It shouldn't be possible to get here before allocating a position,
// which also allocates the root node.
Invariant.Assert(_rootNode != null, "Asking for DeadPositionList before root node create!");
return _rootNode.DeadPositionList;
}
}
#endif // REFCOUNT_DEAD_TEXTPOINTERS
// Collection of highlights applied to TextContainer content.
internal Highlights Highlights
{
get
{
if (_highlights == null)
{
_highlights = new Highlights(this);
}
return _highlights;
}
}
// The root node -- contains all content.
internal TextTreeRootNode RootNode
{
get { return _rootNode; }
}
// The first node contained by the root node -- first toplevel node.
internal TextTreeNode FirstContainedNode
{
get
{
return (_rootNode == null) ? null : (TextTreeNode)_rootNode.GetFirstContainedNode();
}
}
// The last node contained by the root node -- last toplevel node.
internal TextTreeNode LastContainedNode
{
get
{
return (_rootNode == null) ? null : (TextTreeNode)_rootNode.GetLastContainedNode();
}
}
// Undo manager associated with this TextContainer.
// May be null.
internal UndoManager UndoManager
{
get
{
return _undoManager;
}
}
// TextSelection associated with this container.
internal ITextSelection TextSelection
{
get
{
return _textSelection;
}
}
// Returns true if anyone is listening to the Changing, Change or Changed events.
// Notably, this property usually returns false during document load.
internal bool HasListeners
{
get
{
return (this.ChangingHandler != null || this.ChangeHandler != null || this.ChangedHandler != null);
}
}
// Set in the ctor. If true, only plain text may be inserted
// into the TextContainer and perf optimizations are enabled.
internal bool PlainTextOnly
{
get
{
return CheckFlags(Flags.PlainTextOnly);
}
}
// If TRUE, text changes will be collected in TextContainerChangedEventArgs.Changes when
// TextContainerChangedEventArgs.AddChange() is called.
internal bool CollectTextChanges
{
get
{
return CheckFlags(Flags.CollectTextChanges);
}
set
{
SetFlags(value, Flags.CollectTextChanges);
}
}
#endregion Internal Properties
//------------------------------------------------------
//
// Internal Events
//
//------------------------------------------------------
#region Internal Events
event EventHandler ITextContainer.Changing
{
add { Changing += value; }
remove { Changing -= value; }
}
event TextContainerChangeEventHandler ITextContainer.Change
{
add { Change += value; }
remove { Change -= value; }
}
event TextContainerChangedEventHandler ITextContainer.Changed
{
add { Changed += value; }
remove { Changed -= value; }
}
internal event EventHandler Changing
{
add { ChangingHandler += value; }
remove { ChangingHandler -= value; }
}
internal event TextContainerChangeEventHandler Change
{
add { ChangeHandler += value; }
remove { ChangeHandler -= value; }
}
internal event TextContainerChangedEventHandler Changed
{
add { ChangedHandler += value; }
remove { ChangedHandler -= value; }
}
#endregion Internal Events
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
#region Private Methods
// Scans all the immediate contained nodes of a TextElementNode, and
// calls AddLogicalChild methods if supported to alert the children
// about a new parent.
private void ReparentLogicalChildren(SplayTreeNode containerNode, DependencyObject newParentLogicalNode, DependencyObject oldParentLogicalNode)
{
ReparentLogicalChildren(containerNode.GetFirstContainedNode(), null, newParentLogicalNode, oldParentLogicalNode);
}
// Scans all the immediate contained nodes of a TextElementNode, and
// calls AddLogicalChild methods if supported to alert the children
// about a new parent.
private void ReparentLogicalChildren(SplayTreeNode firstChildNode, SplayTreeNode lastChildNode, DependencyObject newParentLogicalNode, DependencyObject oldParentLogicalNode)
{
SplayTreeNode node;
DependencyObject logicalTreeNode;
TextTreeTextElementNode elementNode;
TextTreeObjectNode uiElementNode;
Invariant.Assert(!(newParentLogicalNode == null && oldParentLogicalNode == null), "Both new and old parents should not be null");
for (node = firstChildNode; node != null; node = node.GetNextNode())
{
logicalTreeNode = null;
elementNode = node as TextTreeTextElementNode;
if (elementNode != null)
{
logicalTreeNode = elementNode.TextElement;
}
else
{
uiElementNode = node as TextTreeObjectNode;
if (uiElementNode != null)
{
logicalTreeNode = uiElementNode.EmbeddedElement;
}
}
TextElement textElement = logicalTreeNode as TextElement;
if (textElement != null)
{
textElement.BeforeLogicalTreeChange();
}
try
{
if (oldParentLogicalNode != null)
{
LogicalTreeHelper.RemoveLogicalChild(oldParentLogicalNode, logicalTreeNode);
}
if (newParentLogicalNode != null)
{
LogicalTreeHelper.AddLogicalChild(newParentLogicalNode, logicalTreeNode);
}
}
finally
{
if (textElement != null)
{
textElement.AfterLogicalTreeChange();
}
}
if (node == lastChildNode)
break;
}
}
// This method is called by GetNodeAndEdgeAtOffset to adjust a node
// matching a symbol offset.
//
// When text positions reference both sides of a text run
// we always split the run into a zero-width TextTreeTextNode
// followed by a non-zero-width node. We do this so that
// later we can safely split the non-zero node without disturbing
// existing text positions.
//
// Here, we have to be very careful never to reference a node
// edge between the zero-width node and the non-zero width node.
//
// A: <TextTreeTextNode SymbolCount=0/><TextTreeTextNode SymbolCount=1+/>
// B: <TextTreeTextNode SymbolCount=1+/><TextTreeTextNode SymbolCount=0/>
//
// In case A, if we're searching for the first character in the second
// node, we want to return the first (zero-width) node. A TextPointer
// could be at node1/BeforeBegin but node2/BeforeBegin is invalid.
//
// In case B, if we're searching for the last character in the first
// node, we want to return the second (zero-width) node. A TextPointer
// could be at node2/AfterEnd but not node1/AfterEnd is invalid.
private SplayTreeNode AdjustForZeroWidthNode(SplayTreeNode node, ElementEdge edge)
{
TextTreeTextNode textNode;
SplayTreeNode nextNode;
SplayTreeNode previousNode;
textNode = node as TextTreeTextNode;
if (textNode == null)
{
Invariant.Assert(node.SymbolCount > 0, "Only TextTreeTextNodes may have zero symbol counts!");
return node;
}
if (textNode.SymbolCount == 0)
{
// There are only ever at most two consectuative zero-width
// text nodes (one for each possible position gravity). Make sure
// we chose the following one. This ensures consistency with
// the typical non-zero width case -- we return the node whose
// start edge is closest to a character offset.
nextNode = textNode.GetNextNode();
if (nextNode != null)
{
if (Invariant.Strict)
{
if (nextNode.SymbolCount == 0)
{
// Node and previousNode are logically one text run.
// <TextTreeTextNode SymbolCount=1+/><node SymbolCount=0/><TextTreeTextNode SymbolCount=0/><TextTreeTextNode SymbolCount=1+/>
Invariant.Assert(nextNode is TextTreeTextNode);
Invariant.Assert(!textNode.BeforeStartReferenceCount);
Invariant.Assert(!((TextTreeTextNode)nextNode).AfterEndReferenceCount);
Invariant.Assert(textNode.GetPreviousNode() == null || textNode.GetPreviousNode().SymbolCount > 0, "Found three consecutive zero-width text nodes! (1)");
Invariant.Assert(nextNode.GetNextNode() == null || nextNode.GetNextNode().SymbolCount > 0, "Found three consecutive zero-width text nodes! (2)");
}
}
if (!textNode.BeforeStartReferenceCount)
{
// Node and previousNode are logically one text run.
// <TextTreeTextNode SymbolCount=1+/><node SymbolCount=0/><AnyNode/>
node = nextNode;
}
}
}
else if (edge == ElementEdge.BeforeStart)
{
if (textNode.AfterEndReferenceCount)
{
// <TextTreeTextNode SymbolCount=0/><node SymbolCount=1+/>
// Case A. Check for previous zero-width node.
previousNode = textNode.GetPreviousNode();
if (previousNode != null && previousNode.SymbolCount == 0 && !((TextTreeNode)previousNode).AfterEndReferenceCount)
{
Invariant.Assert(previousNode is TextTreeTextNode);
node = previousNode;
}
}
}
else // edge == ElementEdge.AfterEnd
{
if (textNode.BeforeStartReferenceCount)
{
// B: <node SymbolCount=1+/><TextTreeTextNode SymbolCount=0/>
// Case B. Check for following zero-width node.
nextNode = textNode.GetNextNode();
if (nextNode != null && nextNode.SymbolCount == 0 && !((TextTreeNode)nextNode).BeforeStartReferenceCount)
{
Invariant.Assert(nextNode is TextTreeTextNode);
node = nextNode;
}
}
}
return node;
}
// Inserts an element node into a sibling tree.
// Returns the symbol count of any contained nodes the elementNode covers.
private int InsertElementToSiblingTree(TextPointer startPosition, TextPointer endPosition, TextTreeTextElementNode elementNode)
{
int childSymbolCount = 0;
int childCharCount = 0;
if (startPosition.CompareTo(endPosition) == 0)
{
// Simple insert, no children for elementNode.
// Calculate childCharCount now, before we change position.
// IMELeftEdgeCharCount depends on context.
int childIMECharCount = elementNode.IMECharCount - elementNode.IMELeftEdgeCharCount;
elementNode.InsertAtPosition(startPosition);
if (elementNode.ContainedNode != null)
{
childSymbolCount = elementNode.SymbolCount - 2;
childCharCount = childIMECharCount;
}
}
else
{
// Complex insert, elementNode is going to have children.
childSymbolCount = InsertElementToSiblingTreeComplex(startPosition, endPosition, elementNode, out childCharCount);
}
elementNode.SymbolCount = childSymbolCount + 2;
elementNode.IMECharCount = childCharCount + elementNode.IMELeftEdgeCharCount;
return childSymbolCount;
}
// Inserts an element node into a sibling tree. The node is expected to cover existing content.
// Returns the symbol count of all contained nodes the elementNode covers.
private int InsertElementToSiblingTreeComplex(TextPointer startPosition, TextPointer endPosition, TextTreeTextElementNode elementNode,
out int childCharCount)
{
SplayTreeNode containingNode;
SplayTreeNode leftSubTree;
SplayTreeNode middleSubTree;
SplayTreeNode rightSubTree;
int childSymbolCount;
containingNode = startPosition.GetScopingNode();
// Rip out all the nodes the new element node is going to contain.
childSymbolCount = CutContent(startPosition, endPosition, out childCharCount, out leftSubTree, out middleSubTree, out rightSubTree);
// Join left/right trees under elementNode.
TextTreeNode.Join(elementNode, leftSubTree, rightSubTree);
// Reparent middle tree under elementNode.
elementNode.ContainedNode = middleSubTree;
middleSubTree.ParentNode = elementNode;
// Reparent the whole thing under the original container.
containingNode.ContainedNode = elementNode;
elementNode.ParentNode = containingNode;
return childSymbolCount;
}
// Removes nodes from a sibling tree. containingNode must scope start/end.
// Returns the combined symbol count of all the removed nodes.
private int DeleteContentFromSiblingTree(SplayTreeNode containingNode, TextPointer startPosition, TextPointer endPosition, bool newFirstIMEVisibleNode, out int charCount)
{
SplayTreeNode leftSubTree;
SplayTreeNode middleSubTree;
SplayTreeNode rightSubTree;
SplayTreeNode rootNode;
TextTreeNode previousNode;
ElementEdge previousEdge;
TextTreeNode nextNode;
ElementEdge nextEdge;
int symbolCount;
int symbolOffset;
// Early out in the no-op case. CutContent can't handle an empty content span.
if (startPosition.CompareTo(endPosition) == 0)
{
if (newFirstIMEVisibleNode)
{
UpdateContainerSymbolCount(containingNode, /* symbolCount */ 0, /* charCount */ -1);
}
charCount = 0;
return 0;
}
// Get the symbol offset now before the CutContent call invalidates startPosition.
symbolOffset = startPosition.GetSymbolOffset();
// Do the cut. middleSubTree is what we want to remove.
symbolCount = CutContent(startPosition, endPosition, out charCount, out leftSubTree, out middleSubTree, out rightSubTree);
// We need to remember the original previous/next node for the span
// we're about to drop, so any orphaned positions can find their way
// back.
if (middleSubTree != null)
{
if (leftSubTree != null)
{
previousNode = (TextTreeNode)leftSubTree.GetMaxSibling();
previousEdge = ElementEdge.AfterEnd;
}
else
{
previousNode = (TextTreeNode)containingNode;
previousEdge = ElementEdge.AfterStart;
}
if (rightSubTree != null)
{
nextNode = (TextTreeNode)rightSubTree.GetMinSibling();
nextEdge = ElementEdge.BeforeStart;
}
else
{
nextNode = (TextTreeNode)containingNode;
nextEdge = ElementEdge.BeforeEnd;
}
// Increment previous/nextNode reference counts. This may involve
// splitting a text node, so we use refs.
AdjustRefCountsForContentDelete(ref previousNode, previousEdge, ref nextNode, nextEdge, (TextTreeNode)middleSubTree);
// Make sure left/rightSubTree stay local roots, we might
// have inserted new elements in the AdjustRefCountsForContentDelete call.
if (leftSubTree != null)
{
leftSubTree.Splay();
}
if (rightSubTree != null)
{
rightSubTree.Splay();
}
// Similarly, middleSubtree might not be a local root any more,
// so splay it too.
middleSubTree.Splay();
// Note TextContainer now has no references to middleSubTree, if there are
// no orphaned positions this allocation won't be kept around.
Invariant.Assert(middleSubTree.ParentNode == null, "Assigning fixup node to parented child!");
middleSubTree.ParentNode = new TextTreeFixupNode(previousNode, previousEdge, nextNode, nextEdge);
}
// Put left/right sub trees back into the TextContainer.
rootNode = TextTreeNode.Join(leftSubTree, rightSubTree);
containingNode.ContainedNode = rootNode;
if (rootNode != null)
{
rootNode.ParentNode = containingNode;
}
if (symbolCount > 0)
{
int nextNodeCharDelta = 0;
if (newFirstIMEVisibleNode)
{
// The following node is the new first ime visible sibling.
// It just moved, and loses an edge character.
nextNodeCharDelta = -1;
}
UpdateContainerSymbolCount(containingNode, -symbolCount, -charCount + nextNodeCharDelta);
TextTreeText.RemoveText(_rootNode.RootTextBlock, symbolOffset, symbolCount);
NextGeneration(true /* deletedContent */);
// Notify the TextElement of a content change. Note that any full TextElements
// between startPosition and endPosition will be handled by CutTopLevelLogicalNodes,
// which will move them from this tree to their own private trees without changing
// their contents.
Invariant.Assert(startPosition.Parent == endPosition.Parent);
TextElement textElement = startPosition.Parent as TextElement;
if (textElement != null)
{
textElement.OnTextUpdated();
}
}
return symbolCount;
}
// 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;
}
// Increments the position reference counts on nodes immediately
// preceding and following a delete operation.
//
// Whenever we delete a span of content, we have to worry about any
// positions still referencing the deleted content. They have enough
// information to find their way back to the surrounding nodes, but
// we need to increment the ref count on those nodes now so that they'll
// still be around when the positions need them.
//
// Because incrementing a ref count on a text node edge may involve
// splitting the text node, this method takes refs to nodes and will
// update the refs if a node is split.
//
// Called by DeleteContentFromSiblingTree and ExtractElementInternal.
private void AdjustRefCountsForContentDelete(ref TextTreeNode previousNode, ElementEdge previousEdge,
ref TextTreeNode nextNode, ElementEdge nextEdge,
TextTreeNode middleSubTree)
{
bool leftEdgeReferenceCount;
bool rightEdgeReferenceCount;
leftEdgeReferenceCount = false;
rightEdgeReferenceCount = false;
// Get the count of all positions referencing text node edges across the deleted content.
GetReferenceCounts((TextTreeNode)middleSubTree.GetMinSibling(), ref leftEdgeReferenceCount, ref rightEdgeReferenceCount);
previousNode = previousNode.IncrementReferenceCount(previousEdge, rightEdgeReferenceCount);
nextNode = nextNode.IncrementReferenceCount(nextEdge, leftEdgeReferenceCount);
}
// Sums the reference counts for a node and all following or contained nodes.
private void GetReferenceCounts(TextTreeNode node, ref bool leftEdgeReferenceCount, ref bool rightEdgeReferenceCount)
{
do
{
// We can combine BeforeStart/BeforeEnd and AfterStart/AfterEnd because
// they include all positions with equal gravity.
leftEdgeReferenceCount |= node.BeforeStartReferenceCount || node.BeforeEndReferenceCount;
rightEdgeReferenceCount |= node.AfterStartReferenceCount || node.AfterEndReferenceCount;
if (node.ContainedNode != null)
{
GetReferenceCounts((TextTreeNode)node.ContainedNode.GetMinSibling(), ref leftEdgeReferenceCount, ref rightEdgeReferenceCount);
}
node = (TextTreeNode)node.GetNextNode();
}
while (node != null);
}
// Increments the position reference counts on nodes immediately
// preceding and following a delete operation on a single TextElementNode.
// This is similar to AdjustRefCountsForContentDelete, except that
// in this case we deleting a single node, and positions at the
// BeforeStart/AfterEnd edges may move into contained content, which
// is still live in the tree.
//
// Whenever we delete a span of content, we have to worry about any
// positions still referencing the deleted content. They have enough
// information to find their way back to the surrounding nodes, but
// we need to increment the ref count on those nodes now so that they'll
// still be around when the positions need them.
//
// Because incrementing a ref count on a text node edge may involve
// splitting the text node, this method takes refs to nodes and will
// update the refs if a node is split.
//
// Called by ExtractElementFromSiblingTree.
private void AdjustRefCountsForShallowDelete(ref TextTreeNode previousNode, ElementEdge previousEdge,
ref TextTreeNode nextNode,ElementEdge nextEdge,
ref TextTreeNode firstContainedNode, ref TextTreeNode lastContainedNode,
TextTreeTextElementNode extractedElementNode)
{
previousNode = previousNode.IncrementReferenceCount(previousEdge, extractedElementNode.AfterStartReferenceCount);
nextNode = nextNode.IncrementReferenceCount(nextEdge, extractedElementNode.BeforeEndReferenceCount);
if (firstContainedNode != null)
{
firstContainedNode = firstContainedNode.IncrementReferenceCount(ElementEdge.BeforeStart, extractedElementNode.BeforeStartReferenceCount);
}
else
{
nextNode = nextNode.IncrementReferenceCount(nextEdge, extractedElementNode.BeforeStartReferenceCount);
}
if (lastContainedNode != null)
{
lastContainedNode = lastContainedNode.IncrementReferenceCount(ElementEdge.AfterEnd, extractedElementNode.AfterEndReferenceCount);
}
else
{
previousNode = previousNode.IncrementReferenceCount(previousEdge, extractedElementNode.AfterEndReferenceCount);
}
}
// Splits a sibling tree into three sub trees -- a tree with content before startPosition,
// a tree with content between startPosition/endPosition, and a tree with content following endPosition.
// Any of the subtrees may be null on exit, if they contain no content (eg, if
// startPosition == endPosition, middleSubTree will be null on exit, and so forth).
//
// All returned roots have null ParentNode pointers -- the caller MUST
// reparent all of them, even if deleting content, to ensure orphaned
// TextPositions can find their way back to the original tree.
//
// Returns the symbol count of middleSubTree -- all the content between startPosition and endPosition.
private int CutContent(TextPointer startPosition, TextPointer endPosition, out int charCount, out SplayTreeNode leftSubTree, out SplayTreeNode middleSubTree, out SplayTreeNode rightSubTree)
{
SplayTreeNode childNode;
int symbolCount;
Invariant.Assert(startPosition.GetScopingNode() == endPosition.GetScopingNode(), "startPosition/endPosition not in same sibling tree!");
Invariant.Assert(startPosition.CompareTo(endPosition) != 0, "CutContent doesn't expect empty span!");
// Get the root of all nodes to the left of the split.
switch (startPosition.Edge)
{
case ElementEdge.BeforeStart:
leftSubTree = startPosition.Node.GetPreviousNode();
break;
case ElementEdge.AfterStart:
leftSubTree = null;
break;
case ElementEdge.BeforeEnd:
default:
Invariant.Assert(false, "Unexpected edge!"); // Should have gone to simple insert case.
leftSubTree = null;
break;
case ElementEdge.AfterEnd:
leftSubTree = startPosition.Node;
break;
}
// Get the root of all nodes to the right of the split.
switch (endPosition.Edge)
{
case ElementEdge.BeforeStart:
rightSubTree = endPosition.Node;
break;
case ElementEdge.AfterStart:
default:
Invariant.Assert(false, "Unexpected edge! (2)"); // Should have gone to simple insert case.
rightSubTree = null;
break;
case ElementEdge.BeforeEnd:
rightSubTree = null;
break;
case ElementEdge.AfterEnd:
rightSubTree = endPosition.Node.GetNextNode();
break;
}
// Get the root of all nodes covered by startPosition/endPosition.
if (rightSubTree == null)
{
if (leftSubTree == null)
{
middleSubTree = startPosition.GetScopingNode().ContainedNode;
}
else
{
middleSubTree = leftSubTree.GetNextNode();
}
}
else
{
middleSubTree = rightSubTree.GetPreviousNode();
if (middleSubTree == leftSubTree)
{
middleSubTree = null;
}
}
// Split the tree into three sub trees matching the roots we've found.
if (leftSubTree != null)
{
leftSubTree.Split();
Invariant.Assert(leftSubTree.Role == SplayTreeNodeRole.LocalRoot);
leftSubTree.ParentNode.ContainedNode = null;
leftSubTree.ParentNode = null;
}
symbolCount = 0;
charCount = 0;
if (middleSubTree != null)
{
if (rightSubTree != null)
{
// Split will move middleSubTree up to the root.
middleSubTree.Split();
}
else
{
// Make sure middleSubTree is a root.
middleSubTree.Splay();
}
Invariant.Assert(middleSubTree.Role == SplayTreeNodeRole.LocalRoot, "middleSubTree is not a local root!");
if (middleSubTree.ParentNode != null)
{
middleSubTree.ParentNode.ContainedNode = null;
middleSubTree.ParentNode = null;
}
// Calc the symbol count of the middle tree.
for (childNode = middleSubTree; childNode != null; childNode = childNode.RightChildNode)
{
symbolCount += childNode.LeftSymbolCount + childNode.SymbolCount;
charCount += childNode.LeftCharCount + childNode.IMECharCount;
}
}
if (rightSubTree != null)
{
// Make sure rightSubTree is a root before returning.
// We haven't done anything yet to ensure this.
rightSubTree.Splay();
}
Invariant.Assert(leftSubTree == null || leftSubTree.Role == SplayTreeNodeRole.LocalRoot);
Invariant.Assert(middleSubTree == null || middleSubTree.Role == SplayTreeNodeRole.LocalRoot);
Invariant.Assert(rightSubTree == null || rightSubTree.Role == SplayTreeNodeRole.LocalRoot);
return symbolCount;
}
// ExtractElement worker. Removes a TextElement from the tree.
//
// If deep is true, also removes any content covered by the element.
// In this case element.TextTreeElementNode will be replaced with a
// deep copy of all contained nodes. Since this is a copy, it can
// be safely inserted into a new tree -- no positions reference it.
//
// deep is true when this method is called during a cross-tree insert
// (that is, when a TextElement is extracted from one tree and inserted
// into another via a call to InsertElement).
//
// If deep is true, returns the raw text corresponding to element and
// its contained content. Otherwise returns null.
//
// If deep is true, extractChangeEventArgs will be non-null on exit,
// containing all the information needed to raise a matching TextChanged
// event. Otherwise, extractChangeEventArgs will be null on exit.
private char[] ExtractElementInternal(TextElement element, bool deep, out ExtractChangeEventArgs extractChangeEventArgs)
{
TextTreeTextElementNode elementNode;
SplayTreeNode containingNode;
TextPointer startPosition;
TextPointer endPosition;
bool empty;
int symbolOffset;
char[] elementText;
TextTreeUndoUnit undoUnit;
SplayTreeNode firstContainedChildNode;
SplayTreeNode lastContainedChildNode;
DependencyObject oldLogicalParent;
BeforeAddChange();
firstContainedChildNode = null;
lastContainedChildNode = null;
extractChangeEventArgs = null;
elementText = null;
elementNode = element.TextElementNode;
containingNode = elementNode.GetContainingNode();
empty = (elementNode.ContainedNode == null);
startPosition = new TextPointer(this, elementNode, ElementEdge.BeforeStart, LogicalDirection.Backward);
// We only need the end position if this element originally spanned any content.
endPosition = null;
if (!empty)
{
endPosition = new TextPointer(this, elementNode, ElementEdge.AfterEnd, LogicalDirection.Backward);
}
symbolOffset = elementNode.GetSymbolOffset(this.Generation);
// Remember the old parent
oldLogicalParent = ((TextTreeNode)containingNode).GetLogicalTreeNode();
// Invalidate any TextElementCollection that depends on the parent.
// Make sure we do that before raising any public events.
TextElementCollectionHelper.MarkDirty(oldLogicalParent);
// Remove the element from the logical tree.
// NB: we do this even for a deep extract, because we can't wait --
// during a deep extract/move to new tree, the property system must be
// notified before the element moves into its new tree.
element.BeforeLogicalTreeChange();
try
{
LogicalTreeHelper.RemoveLogicalChild(oldLogicalParent, element);
}
finally
{
element.AfterLogicalTreeChange();
}
// Handle undo.
if (deep && !empty)
{
undoUnit = TextTreeUndo.CreateDeleteContentUndoUnit(this, startPosition, endPosition);
}
else
{
undoUnit = TextTreeUndo.CreateExtractElementUndoUnit(this, elementNode);
}
// Save the first/last contained node now -- after the ExtractElementFromSiblingTree
// call it will be too late to find them.
if (!deep && !empty)
{
firstContainedChildNode = elementNode.GetFirstContainedNode();
lastContainedChildNode = elementNode.GetLastContainedNode();
}
// Record all the IME related char state before the extract.
int imeCharCount = elementNode.IMECharCount;
int imeLeftEdgeCharCount = elementNode.IMELeftEdgeCharCount;
int nextNodeCharDelta = 0;
// DevDiv.1092668 We care about the next node only if it will become the First IME Visible Sibling
// after the extraction. If this is a deep extract we shouldn't care if the element is empty,
// since all of its contents are getting extracted as well
TextTreeTextElementNode nextNode = null;
if ((deep || empty) && element.IsFirstIMEVisibleSibling)
{
nextNode = (TextTreeTextElementNode)elementNode.GetNextNode();
if (nextNode != null)
{
// The following node is the new first ime visible sibling.
// It just moved, and loses an edge character.
nextNodeCharDelta = -nextNode.IMELeftEdgeCharCount;
nextNode.IMECharCount += nextNodeCharDelta;
}
}
// Rip the element out of its sibling tree.
// If this is a deep extract element's TextElementNode will be updated
// with a deep copy of all contained nodes.
ExtractElementFromSiblingTree(containingNode, elementNode, deep);
// The first contained node of the extracted node may no longer
// be a first sibling after the parent extract. If that's the case,
// update its char count.
int containedNodeCharDelta = 0;
TextTreeTextElementNode firstContainedElementNode = firstContainedChildNode as TextTreeTextElementNode;
if (firstContainedElementNode != null)
{
containedNodeCharDelta = firstContainedElementNode.IMELeftEdgeCharCount;
firstContainedElementNode.IMECharCount += containedNodeCharDelta;
}
if (!deep)
{
// Unlink the TextElement from the TextElementNode.
element.TextElementNode = null;
// Pull out the edge symbols from the text store.
TextTreeText.RemoveElementEdges(_rootNode.RootTextBlock, symbolOffset, elementNode.SymbolCount);
}
else
{
// We leave element.TextElement alone, since for a deep extract we've already
// stored a copy of the original nodes there that we'll use in a following insert.
// Cut and return the matching symbols.
elementText = TextTreeText.CutText(_rootNode.RootTextBlock, symbolOffset, elementNode.SymbolCount);
}
// Ancestor nodes lose either the whole node or two element edge symbols, depending
// on whether or not this is a deep extract.
if (deep)
{
UpdateContainerSymbolCount(containingNode, -elementNode.SymbolCount, -imeCharCount + nextNodeCharDelta + containedNodeCharDelta);
}
else
{
UpdateContainerSymbolCount(containingNode, /* symbolCount */ -2, /* charCount */ -imeLeftEdgeCharCount + nextNodeCharDelta + containedNodeCharDelta);
}
NextGeneration(true /* deletedContent */);
if (undoUnit != null)
{
undoUnit.SetTreeHashCode();
}
// Raise the public event.
if (deep)
{
extractChangeEventArgs = new ExtractChangeEventArgs(this, startPosition, elementNode, nextNodeCharDelta == 0 ? null : nextNode, containedNodeCharDelta == 0 ? null : firstContainedElementNode, imeCharCount, imeCharCount - imeLeftEdgeCharCount);
}
else if (empty)
{
AddChange(startPosition, /* symbolCount */ 2, /* charCount */ imeCharCount, PrecursorTextChangeType.ContentRemoved);
}
else
{
AddChange(startPosition, endPosition, elementNode.SymbolCount,
imeLeftEdgeCharCount,
imeCharCount - imeLeftEdgeCharCount,
PrecursorTextChangeType.ElementExtracted, null, false);
}
// Raise events for nodes that just gained or lost an IME char due
// to changes in their surroundings.
if (extractChangeEventArgs == null)
{
if (nextNodeCharDelta != 0)
{
RaiseEventForNewFirstIMEVisibleNode(nextNode);
}
if (containedNodeCharDelta != 0)
{
RaiseEventForFormerFirstIMEVisibleNode(firstContainedElementNode);
}
}
if (!deep && !empty)
{
ReparentLogicalChildren(firstContainedChildNode, lastContainedChildNode, oldLogicalParent /* new parent */, element /* old parent */);
}
//
// Remove char count for logical break, since the element is leaving the tree.
//
if (null != element.TextElementNode)
{
element.TextElementNode.IMECharCount -= imeLeftEdgeCharCount;
}
return elementText;
}
// Removes an element node from its sibling tree.
//
// If deep == true, then this method also removes any contained nodes
// and returns a deep copy of them.
//
// If deep == false, any contained nodes are inserted into the original
// node's sibling tree.
private void ExtractElementFromSiblingTree(SplayTreeNode containingNode, TextTreeTextElementNode elementNode, bool deep)
{
TextTreeNode previousNode;
ElementEdge previousEdge;
TextTreeNode nextNode;
ElementEdge nextEdge;
SplayTreeNode childNode;
SplayTreeNode minChildNode;
SplayTreeNode maxChildNode;
SplayTreeNode localRootNode;
TextTreeNode firstContainedNode;
TextTreeNode lastContainedNode;
// Remember the nodes surrounding the one we're going to remove.
previousNode = (TextTreeNode)elementNode.GetPreviousNode();
previousEdge = ElementEdge.AfterEnd;
if (previousNode == null)
{
previousNode = (TextTreeNode)containingNode;
previousEdge = ElementEdge.AfterStart;
}
nextNode = (TextTreeNode)elementNode.GetNextNode();
nextEdge = ElementEdge.BeforeStart;
if (nextNode == null)
{
nextNode = (TextTreeNode)containingNode;
nextEdge = ElementEdge.BeforeEnd;
}
// Remove the element node.
elementNode.Remove();
Invariant.Assert(elementNode.Role == SplayTreeNodeRole.LocalRoot);
if (deep)
{
// Increment previous/nextNode reference counts. This may involve
// splitting a text node, so we use refs.
AdjustRefCountsForContentDelete(ref previousNode, previousEdge, ref nextNode, nextEdge, elementNode);
// Reparent the removed node with a FixupNode, so that any orphaned
// positions can find their way back to the tree.
// We have to do this after the AdjustRefCountsForContentDelete call, because the fixup
// node doesn't act like a regular node.
elementNode.ParentNode = new TextTreeFixupNode(previousNode, previousEdge, nextNode, nextEdge);
DeepCopy(elementNode);
}
else
{
// Reparent contained nodes to elementNode's parent.
childNode = elementNode.ContainedNode;
elementNode.ContainedNode = null;
if (childNode != null)
{
childNode.ParentNode = null;
firstContainedNode = (TextTreeNode)childNode.GetMinSibling();
lastContainedNode = (TextTreeNode)childNode.GetMaxSibling();
}
else
{
firstContainedNode = null;
lastContainedNode = null;
}
// Increment previous/nextNode reference counts. This may involve
// splitting a text node, so we use refs.
AdjustRefCountsForShallowDelete(ref previousNode, previousEdge, ref nextNode, nextEdge, ref firstContainedNode, ref lastContainedNode, elementNode);
// Reparent the removed node with a FixupNode, so that any orphaned
// positions can find their way back to the tree.
// We have to do this after the AdjustRefCountsForContentDelete call, because the fixup
// node doesn't act like a regular node.
elementNode.ParentNode = new TextTreeFixupNode(previousNode, previousEdge, nextNode, nextEdge, firstContainedNode, lastContainedNode);
if (childNode != null)
{
// Get previous/next nodes into roots of individual trees.
// Then merge them with the element's children.
// We need to splay childNode because it may no longer be a local root.
// The addrefs in AdjustRefCountsForShallowDelete may have created new nodes
// and shuffled the tree.
childNode.Splay();
localRootNode = childNode;
if (previousNode != containingNode)
{
previousNode.Split();
Invariant.Assert(previousNode.Role == SplayTreeNodeRole.LocalRoot);
Invariant.Assert(previousNode.RightChildNode == null);
minChildNode = childNode.GetMinSibling();
minChildNode.Splay();
previousNode.RightChildNode = minChildNode;
minChildNode.ParentNode = previousNode;
localRootNode = previousNode;
}
if (nextNode != containingNode)
{
nextNode.Splay();
Invariant.Assert(nextNode.Role == SplayTreeNodeRole.LocalRoot);
Invariant.Assert(nextNode.LeftChildNode == null);
maxChildNode = childNode.GetMaxSibling();
maxChildNode.Splay();
nextNode.LeftChildNode = maxChildNode;
nextNode.LeftSymbolCount += maxChildNode.LeftSymbolCount + maxChildNode.SymbolCount;
nextNode.LeftCharCount += maxChildNode.LeftCharCount + maxChildNode.IMECharCount;
maxChildNode.ParentNode = nextNode;
localRootNode = nextNode;
}
containingNode.ContainedNode = localRootNode;
if (localRootNode != null)
{
localRootNode.ParentNode = containingNode;
}
}
}
}
// Returns a copy of elementNode and all its children. The copy is
// guaranteed to have no position references.
//
// All TextElements referencing TextTreeTextElementNodes in the copy
// are adjusted to point to the new copied nodes.
private TextTreeTextElementNode DeepCopy(TextTreeTextElementNode elementNode)
{
TextTreeTextElementNode clone;
clone = (TextTreeTextElementNode)elementNode.Clone();
elementNode.TextElement.TextElementNode = clone;
if (elementNode.ContainedNode != null)
{
clone.ContainedNode = DeepCopyContainedNodes((TextTreeNode)elementNode.ContainedNode.GetMinSibling());
clone.ContainedNode.ParentNode = clone;
}
return clone;
}
// Returns a copy of a sibling tree. node is expected to be the first sibling.
private TextTreeNode DeepCopyContainedNodes(TextTreeNode node)
{
TextTreeNode rootClone;
TextTreeNode previousClone;
TextTreeNode clone;
TextTreeTextElementNode elementNode;
rootClone = null;
previousClone = null;
do
{
elementNode = node as TextTreeTextElementNode;
if (elementNode != null)
{
clone = DeepCopy(elementNode);
}
else
{
clone = node.Clone();
}
// clone will be null in one case: if we're trying to clone an
// empty TextNode. We can skip empty TextNodes (symbol count == 0)
// because we know the clones have no TextPointer references, so
// an empty node serves no purpose.
Invariant.Assert(clone != null || node is TextTreeTextNode && node.SymbolCount == 0);
if (clone != null)
{
clone.ParentNode = previousClone;
if (previousClone != null)
{
previousClone.RightChildNode = clone;
}
else
{
Invariant.Assert(clone.Role == SplayTreeNodeRole.LocalRoot);
// Remember the first clone created.
rootClone = clone;
}
previousClone = clone;
}
node = (TextTreeNode)node.GetNextNode();
}
while (node != null);
return rootClone;
}
// Lazy allocates the root node, which we don't need until someone asks
// for Start/End.
private void DemandCreatePositionState()
{
if (_rootNode == null)
{
_rootNode = new TextTreeRootNode(this);
}
}
// Lazy initializer for the TextTreeText. Called just before content insertion.
private void DemandCreateText()
{
Invariant.Assert(_rootNode != null, "Unexpected DemandCreateText call before position allocation.");
if (_rootNode.RootTextBlock == null)
{
_rootNode.RootTextBlock = new TextTreeRootTextBlock();
// Insert the root node (this TextTree) element edges.
TextTreeText.InsertElementEdges(_rootNode.RootTextBlock, 0, 0);
}
}
// Updates the SymbolCount for node's container nodes -- all the way to the TextTree root.
private void UpdateContainerSymbolCount(SplayTreeNode containingNode, int symbolCount, int charCount)
{
do
{
containingNode.Splay();
containingNode.SymbolCount += symbolCount;
containingNode.IMECharCount += charCount;
containingNode = containingNode.ParentNode;
}
while (containingNode != null);
}
// Increments the tree's generation counter. This method should be
// called anytime the tree's content changes.
//
// TextPointers only need to worry about deletions, hence the deletedContent
// parameter which should be set true if any content was removed.
//
// Note we're ignoring wrap-around on the generation counter. If we average
// one edit per second it will take 136 years to overflow.
private void NextGeneration(bool deletedContent)
{
AssertTree();
AssertTreeAndTextSize();
_rootNode.Generation++;
if (deletedContent)
{
_rootNode.PositionGeneration++;
}
// Layout generation is a superset.
NextLayoutGeneration();
}
// Copies a LocalValueEnumerator properties into an array of DependencyProperty.
// This method is useful because LocalValueEnumerator does not support
// setting or clearing local values while enumerating.
private DependencyProperty[] LocalValueEnumeratorToArray(LocalValueEnumerator valuesEnumerator)
{
DependencyProperty[] properties;
int count;
properties = new DependencyProperty[valuesEnumerator.Count];
count = 0;
valuesEnumerator.Reset();
while (valuesEnumerator.MoveNext())
{
properties[count++] = valuesEnumerator.Current.Property;
}
return properties;
}
#region ValidateXXXHelpers
// Validation for SetValue.
private void ValidateSetValue(TextPointer position)
{
TextElement element;
if (position.TextContainer != this)
{
throw new InvalidOperationException(SR.Format(SR.NotInThisTree, "position"));
}
position.SyncToTreeGeneration();
element = position.Parent as TextElement;
if (element == null)
{
throw new InvalidOperationException(SR.NoElement);
}
}
#endregion ValidateXXXHelpers
// Verifies the TextContainer symbol count is in synch with the TextTreeText
// character count.
private void AssertTreeAndTextSize()
{
if (Invariant.Strict)
{
int count;
TextTreeTextBlock textBlock;
if (_rootNode.RootTextBlock != null)
{
count = 0;
for (textBlock = (TextTreeTextBlock)_rootNode.RootTextBlock.ContainedNode.GetMinSibling(); textBlock != null; textBlock = (TextTreeTextBlock)textBlock.GetNextNode())
{
Invariant.Assert(textBlock.Count > 0, "Empty TextBlock!");
count += textBlock.Count;
}
Invariant.Assert(count == this.InternalSymbolCount, "TextContainer.SymbolCount does not match TextTreeText size!");
}
}
}
#if DEBUG_SLOW
private void AssertTreeRecursive(TextTreeNode containingNode)
{
TextTreeNode node;
if (containingNode.ContainedNode == null)
{
Invariant.Assert(containingNode.ParentNode == null || containingNode.ParentNode.ContainedNode == containingNode);
return;
}
Invariant.Assert(containingNode.ContainedNode.ParentNode == containingNode);
for (node = (TextTreeNode)containingNode.ContainedNode.GetMinSibling(); node != null; node = (TextTreeNode)node.GetNextNode())
{
if (node != containingNode.ContainedNode)
{
Invariant.Assert(node.ParentNode.LeftChildNode == node || node.ParentNode.RightChildNode == node);
}
Invariant.Assert(node.SymbolCount >= 0);
if (node.SymbolCount == 0)
{
Invariant.Assert(node is TextTreeTextNode);
Invariant.Assert(node.BeforeStartReferenceCount > 0 || node.AfterEndReferenceCount > 0);
}
if (node.ContainedNode != null)
{
AssertTreeRecursive((TextTreeNode)node.ContainedNode);
}
}
}
#endif // DEBUG_SLOW
// Worker for internal Begin methods.
private void BeginChange(bool undo)
{
if (undo && _changeBlockUndoRecord == null && _changeBlockLevel == 0)
{
Invariant.Assert(_changeBlockLevel == 0);
_changeBlockUndoRecord = new ChangeBlockUndoRecord(this, String.Empty);
}
// Disable processing of the queue during change notifications to prevent reentrancy.
if (_changeBlockLevel == 0)
{
DemandCreatePositionState(); // Ensure _rootNode != null.
if (this.Dispatcher != null)
{
_rootNode.DispatcherProcessingDisabled = this.Dispatcher.DisableProcessing();
}
}
_changeBlockLevel++;
// We'll raise the Changing event when/if we get an actual
// change added, inside BeforeAddChange.
}
// Worker for AddChange, fires a Change event.
private void FireChangeEvent(TextPointer startPosition, TextPointer endPosition, int symbolCount,
int leftEdgeCharCount, int childCharCount,
PrecursorTextChangeType precursorTextChange, DependencyProperty property, bool affectsRenderOnly)
{
Invariant.Assert(this.ChangeHandler != null);
// Set a flag to disallow reentrant edits. We really can't support
// that here, because any edits to the document would break the
// BeginChange/EndChange contract (no edits by listeners in a change
// block!).
// (Note, we will allow re-entrant property changes only, because
// property change events are not exposed publicly on TextBox or RTB.)
SetFlags(true, Flags.ReadOnly);
try
{
if (precursorTextChange == PrecursorTextChangeType.ElementAdded)
{
Invariant.Assert(symbolCount > 2, "ElementAdded must span at least two element edges and one content symbol!");
TextContainerChangeEventArgs args1 = new TextContainerChangeEventArgs(startPosition, 1, leftEdgeCharCount, TextChangeType.ContentAdded);
TextContainerChangeEventArgs args2 = new TextContainerChangeEventArgs(endPosition, 1, 0, TextChangeType.ContentAdded);
ChangeHandler(this, args1);
ChangeHandler(this, args2);
}
else if (precursorTextChange == PrecursorTextChangeType.ElementExtracted)
{
Invariant.Assert(symbolCount > 2, "ElementExtracted must span at least two element edges and one content symbol!");
TextContainerChangeEventArgs args1 = new TextContainerChangeEventArgs(startPosition, 1, leftEdgeCharCount, TextChangeType.ContentRemoved);
TextContainerChangeEventArgs args2 = new TextContainerChangeEventArgs(endPosition, 1, 0, TextChangeType.ContentRemoved);
ChangeHandler(this, args1);
ChangeHandler(this, args2);
}
else
{
TextContainerChangeEventArgs args = new TextContainerChangeEventArgs(startPosition, symbolCount, leftEdgeCharCount + childCharCount, ConvertSimplePrecursorChangeToTextChange(precursorTextChange), property, affectsRenderOnly);
ChangeHandler(this, args);
}
}
finally
{
SetFlags(false, Flags.ReadOnly);
}
}
// Returns the TextChange matching an ContentAdded, ContentRemoved,
// or PropertyModified PrecursorTextChange.
private TextChangeType ConvertSimplePrecursorChangeToTextChange(PrecursorTextChangeType precursorTextChange)
{
Invariant.Assert(precursorTextChange != PrecursorTextChangeType.ElementAdded && precursorTextChange != PrecursorTextChangeType.ElementExtracted);
return (TextChangeType)precursorTextChange;
}
// Helper for DeleteContentInternal.
// If startPosition is placed at the very front of its parent's sibling list,
// returns the next sibling following endPositoin (the new head of the sibling
// list). The new head node is interesting because its IMELeftEdgeCharCount may
// change because of its new position.
private TextTreeTextElementNode GetNextIMEVisibleNode(TextPointer startPosition, TextPointer endPosition)
{
TextTreeTextElementNode nextIMEVisibleNode = null;
TextElement adjacentElement = startPosition.GetAdjacentElement(LogicalDirection.Forward) as TextElement;
if (adjacentElement != null && adjacentElement.IsFirstIMEVisibleSibling)
{
nextIMEVisibleNode = (TextTreeTextElementNode)endPosition.GetAdjacentSiblingNode(LogicalDirection.Forward);
}
return nextIMEVisibleNode;
}
// Fires Change events for IMELeftEdgeCharCount deltas to a node after it
// moves out of position such that it is no longer the leftmost child
// of its parent.
private void RaiseEventForFormerFirstIMEVisibleNode(TextTreeNode node)
{
TextPointer startEdgePosition = new TextPointer(this, node, ElementEdge.BeforeStart);
// Next node was the old first node. Its IMECharCount
// just bumped up, report that.
AddChange(startEdgePosition, /* symbolCount */ 0, /* IMECharCount */ 1, PrecursorTextChangeType.ContentAdded);
}
// Fires Change events for IMELeftEdgeCharCount deltas to a node after it
// moves into position such that it is the leftmost child
// of its parent.
private void RaiseEventForNewFirstIMEVisibleNode(TextTreeNode node)
{
TextPointer startEdgePosition = new TextPointer(this, node, ElementEdge.BeforeStart);
// node was the old second node. Its IMECharCount
// just dropped down, report that.
AddChange(startEdgePosition, /* symbolCount */ 0, /* IMECharCount */ 1, PrecursorTextChangeType.ContentRemoved);
}
// Sets boolean state.
private void SetFlags(bool value, Flags flags)
{
_flags = value ? (_flags | flags) : (_flags & (~flags));
}
// Reads boolean state.
private bool CheckFlags(Flags flags)
{
return ((_flags & flags) == flags);
}
#endregion Private methods
//------------------------------------------------------
//
// Private Properties
//
//------------------------------------------------------
#region Private Properties
// Dispatcher associated with the parent of this TextContainer, or
// null if the TextContainer has no parent.
private Dispatcher Dispatcher
{
get
{
return (this.Parent != null) ? this.Parent.Dispatcher : null;
}
}
#endregion Private Properties
//------------------------------------------------------
//
// Private Types
//
//------------------------------------------------------
#region Private Types
// Holds the state for delayed ChangeEvent.
// We delay change events for element extracts when a TextElement is
// being moved from tree to another. When the TextElement is safely
// in the new tree, then we raise a change event in the old tree.
private class ExtractChangeEventArgs
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
// Creates a new instance.
internal ExtractChangeEventArgs(TextContainer textTree, TextPointer startPosition, TextTreeTextElementNode node,
TextTreeTextElementNode newFirstIMEVisibleNode, TextTreeTextElementNode formerFirstIMEVisibleNode, int charCount, int childCharCount)
{
_textTree = textTree;
_startPosition = startPosition;
_symbolCount = node.SymbolCount;
_charCount = charCount;
_childCharCount = childCharCount;
_newFirstIMEVisibleNode = newFirstIMEVisibleNode;
_formerFirstIMEVisibleNode = formerFirstIMEVisibleNode;
}
#endregion Constructors
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
// Fires change event recorded in this object.
internal void AddChange()
{
_textTree.AddChange(_startPosition, _symbolCount, _charCount, PrecursorTextChangeType.ContentRemoved);
if (_newFirstIMEVisibleNode != null)
{
_textTree.RaiseEventForNewFirstIMEVisibleNode(_newFirstIMEVisibleNode);
}
if (_formerFirstIMEVisibleNode != null)
{
_textTree.RaiseEventForFormerFirstIMEVisibleNode(_formerFirstIMEVisibleNode);
}
}
#endregion Internal Methods
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
#region Internal Properties
// TextContainer associated with the pending event.
internal TextContainer TextContainer { get { return _textTree; } }
// Count of chars covered the extracted element, not counting edges.
internal int ChildIMECharCount { get { return _childCharCount; } }
#endregion Internal Properties
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
// TextContainer associated with the pending event.
private readonly TextContainer _textTree;
// TextPointer associated with the pending event.
// This is the position immediately precedining the former location
// of the extracted element.
private readonly TextPointer _startPosition;
// Count of symbols covered by the extracted element, including the
// two element edges.
private readonly int _symbolCount;
// Count of chars covered the extracted element.
private readonly int _charCount;
// Count of chars covered the extracted element, not counting edges.
private readonly int _childCharCount;
// Next node following the extracted node.
private readonly TextTreeTextElementNode _newFirstIMEVisibleNode;
// Former first contained node of the extracted node.
private readonly TextTreeTextElementNode _formerFirstIMEVisibleNode;
#endregion Private Fields
}
// Booleans for the _flags field.
[System.Flags]
private enum Flags
{
// Set true during TextContainer.Change event callback.
// When true, modifying the TextContainer is disallowed.
ReadOnly = 0x1,
// Set in the ctor. If true, only plain text may be inserted
// into the TextContainer and perf optimizations are enabled.
PlainTextOnly = 0x2,
// Set in the ctor. Passed on to TextContainerChangedEventArgs to control
// whether or not content changes are tracked.
CollectTextChanges = 0x4,
}
#endregion Private Types
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
//
// !!! IMPORTANT !!!
//
// Before adding new fields to TextContainer, consider adding them instead
// to TextTreeRootNode. We lazy allocate the root node when TextPositions
// are allocated (before any content can be inserted), so it's usually
// a more appropriate place for state. Keep empty trees cheap!
//
// Parent DependencyObject, supplied in ctor. May be null.
private readonly DependencyObject _parent;
// Root node of the tree. Lazy allocated when the first TextPointer
// is requested.
private TextTreeRootNode _rootNode;
// Collection of highlights applied to TextContainer content.
private Highlights _highlights;
// BeginChange ref count. When non-zero, we are inside a change block.
private int _changeBlockLevel;
// Array of pending changes in the current change block.
// Null outside of a change block.
private TextContainerChangedEventArgs _changes;
// TextView associated with this TextContainer.
private ITextView _textview;
// Undo manager associated with this TextContainer.
// May be null.
private UndoManager _undoManager;
// TextSelection associated with this container.
private ITextSelection _textSelection;
// Undo unit associated with the current change block, if any.
private ChangeBlockUndoRecord _changeBlockUndoRecord;
// implementation of ITextContainer.Changing
private EventHandler ChangingHandler;
// implementation of ITextContainer.Change
private TextContainerChangeEventHandler ChangeHandler;
// implementation of ITextContainer.Changed
private TextContainerChangedEventHandler ChangedHandler;
// Boolean flags, set with Flags enum.
private Flags _flags;
#if DEBUG
private int _debugId = TextTreeNode.GetDebugId();
#endif // DEBUG
#endregion Private Fields
}
}
|