void OnPencilDisposed(Pencil pencil, TextDataChangedEventArgs args)
{
Debug.Assert(pencil == this.activePencil, "Disposing a pencil that isn't the active one.");
if (args != null)
{
if (this.LastChange != null)
{
this.LastChange.NextChange = args.Change;
}
TextChange finalChange = args.Change;
while (finalChange.NextChange != null)
{
finalChange = finalChange.NextChange;
}
this.TextData = finalChange.NewTextData;
this.LastChange = finalChange;
var handler = this.TextDataChanged;
if (handler != null)
{
handler(this, args);
}
if (pencil.UndoUnit != null)
{
var now = DateTime.Now;
bool merged = false;
if (((now - this.timeOfLastEdit).TotalMilliseconds < MinimumMillisecondsTimeBetweenUndoUnits) && (this.undoStack.Count > 0))
{
// If possible, merge this unit with the one on the stack.
TextUndoUnit existingUnit = this.undoStack.Peek();
TextUndoUnit incomingUnit = pencil.UndoUnit;
if (incomingUnit.Metadata != null && incomingUnit.Metadata.TryMerge(existingUnit.Metadata))
{
// Successful merge
existingUnit.Metadata = incomingUnit.Metadata;
existingUnit.Merge(pencil.UndoUnit);
merged = true;
}
}
if (!merged)
{
this.undoStack.Push(pencil.UndoUnit);
}
this.redoStack.Clear();
this.timeOfLastEdit = now;
}
}
this.activePencil = null;
this.pencilEvent.Set();
}
void NotifyAfterUndoRedo(TextUndoUnit unit, object instigator, bool isUndo)
{
foreach (var observer in this.undoObservers)
{
observer.OnAfterUndoRedoUnit(unit, instigator, isUndo);
}
}
internal void Merge(TextUndoUnit incomingUnit)
{
if (this.changes == null)
{
this.changes = incomingUnit.changes;
}
else if (incomingUnit.changes != null)
{
this.changes.AddRange(incomingUnit.changes);
}
}
public Pencil(TextBuffer buffer, bool forUndoRedo)
{
this.buffer = buffer;
this.firstChange = null;
this.lastChange = null;
if (!forUndoRedo)
{
this.undoUnit = new TextUndoUnit();
}
}
internal void Merge(TextUndoUnit incomingUnit)
{
if (this.changes == null)
{
this.changes = incomingUnit.changes;
}
else if (incomingUnit.changes != null)
{
this.changes.AddRange(incomingUnit.changes);
}
}
public void Redo(object instigator)
{
TextUndoUnit unit = null;
using (var pencil = GetPencil(forUndoRedo: true))
{
if (this.redoStack.Count > 0)
{
unit = this.redoStack.Pop();
NotifyBeforeUndoRedo(unit, instigator, isUndo: false);
unit.Redo(pencil);
this.undoStack.Push(unit);
}
}
if (unit != null)
{
NotifyAfterUndoRedo(unit, instigator, isUndo: false);
}
}
void ITextUndoObserver.OnAfterUndoRedoUnit(TextUndoUnit unit, object instigator, bool isUndo)
{
if (object.ReferenceEquals(instigator, this))
{
var meta = unit.Metadata as SelectionUndoMetadata;
if (meta != null)
{
var selection = isUndo ? meta.OldSelection : meta.NewSelection;
if (selection.IsEmpty)
{
MoveCaret(selection.Span.Start, false);
}
else if (selection.AnchoredAtTop)
{
this.SelectionAnchor = selection.Span.Start;
MoveCaret(selection.Span.End, true);
}
else
{
this.SelectionAnchor = selection.Span.End;
MoveCaret(selection.Span.Start, true);
}
}
this.inUndoRedo = false;
}
}
void ITextUndoObserver.OnBeforeUndoRedoUnit(TextUndoUnit unit, object instigator, bool isUndo)
{
if (object.ReferenceEquals(instigator, this))
{
this.inUndoRedo = true;
}
}
public Pencil(TextBuffer buffer, bool forUndoRedo)
{
this.buffer = buffer;
this.firstChange = null;
this.lastChange = null;
if (!forUndoRedo)
{
this.undoUnit = new TextUndoUnit();
}
}
void NotifyAfterUndoRedo(TextUndoUnit unit, object instigator, bool isUndo)
{
foreach (var observer in this.undoObservers)
{
observer.OnAfterUndoRedoUnit(unit, instigator, isUndo);
}
}
