When moving text using drag'n'drop, combine text removal on drag and text insertion on drop into a single undo group.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@3839 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/WeakReferenceTests.cs

@@ -31,21 +31,21 @@ namespace ICSharpCode.AvalonEdit.Tests
 		{
 			bool collectedTextView = false;
 			TextDocument textDocument = new TextDocument();
-			Assert.AreEqual(0, textDocument.LineTracker.Count);
+			Assert.AreEqual(0, textDocument.LineTrackers.Count);
 			
 			TextView textView = new TextViewWithGCCallback(delegate { collectedTextView = true; });
 			textView.Document = textDocument;
-			Assert.AreEqual(1, textDocument.LineTracker.Count);
+			Assert.AreEqual(1, textDocument.LineTrackers.Count);
 			textView = null;
 			
 			GarbageCollect();
 			Assert.IsTrue(collectedTextView);
 			// document cannot immediately clear the line tracker
-			Assert.AreEqual(1, textDocument.LineTracker.Count);
+			Assert.AreEqual(1, textDocument.LineTrackers.Count);
 			
 			// but it should clear it on the next change
 			textDocument.Insert(0, "a");
-			Assert.AreEqual(0, textDocument.LineTracker.Count);
+			Assert.AreEqual(0, textDocument.LineTrackers.Count);
 		}
 		
 		[Test]

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/UndoStack.cs

@@ -49,21 +49,66 @@ namespace ICSharpCode.AvalonEdit.Document
 		int undoGroupDepth;
 		int actionCountInUndoGroup;
 		int optionalActionCount;
+		object lastGroupDescriptor;
+		
+		/// <summary>
+		/// If an undo group is open, gets the group descriptor of the current top-level
+		/// undo group.
+		/// If no undo group is open, gets the group descriptor from the previous undo group.
+		/// </summary>
+		/// <remarks>The group descriptor can be used to join adjacent undo groups:
+		/// use a group descriptor to mark your changes, and on the second action,
+		/// compare LastGroupDescriptor and use <see cref="StartContinuedUndoGroup"/> if you
+		/// want to join the undo groups.</remarks>
+		public object LastGroupDescriptor {
+			get { return lastGroupDescriptor; }
+		}
 		
 		/// <summary>
 		/// Starts grouping changes.
 		/// Maintains a counter so that nested calls are possible.
 		/// </summary>
 		public void StartUndoGroup()
+		{
+			StartUndoGroup(null);
+		}
+		
+		/// <summary>
+		/// Starts grouping changes.
+		/// Maintains a counter so that nested calls are possible.
+		/// </summary>
+		/// <param name="groupDescriptor">An object that is stored with the undo group.
+		/// If this is not a top-level undo group, the parameter is ignored.</param>
+		public void StartUndoGroup(object groupDescriptor)
 		{
 			if (undoGroupDepth == 0) {
 				actionCountInUndoGroup = 0;
 				optionalActionCount = 0;
+				lastGroupDescriptor = groupDescriptor;
 			}
 			undoGroupDepth++;
 			//Util.LoggingService.Debug("Open undo group (new depth=" + undoGroupDepth + ")");
 		}
 		
+		/// <summary>
+		/// Starts grouping changes, continuing with the previously closed undo group.
+		/// Maintains a counter so that nested calls are possible.
+		/// If the call to StartContinuedUndoGroup is a nested call, it behaves exactly
+		/// as <see cref="StartUndoGroup()"/>, only top-level calls can continue existing undo groups.
+		/// </summary>
+		/// <param name="groupDescriptor">An object that is stored with the undo group.
+		/// If this is not a top-level undo group, the parameter is ignored.</param>
+		public void StartContinuedUndoGroup(object groupDescriptor)
+		{
+			if (undoGroupDepth == 0) {
+				actionCountInUndoGroup = undostack.Count > 0 ? 1 : 0;
+				optionalActionCount = 0;
+				lastGroupDescriptor = groupDescriptor;
+			}
+			undoGroupDepth++;
+			//Util.LoggingService.Debug("Continue undo group (new depth=" + undoGroupDepth + ")");
+		}
+		
 		/// <summary>
 		/// Stops grouping changes.
 		/// </summary>
@@ -102,6 +147,7 @@ namespace ICSharpCode.AvalonEdit.Document
 		{
 			VerifyNoUndoGroupOpen();
 			if (undostack.Count > 0) {
+				lastGroupDescriptor = null;
 				acceptChanges = false;
 				IUndoableOperation uedit = undostack.Pop();
 				redostack.Push(uedit);
@@ -121,6 +167,7 @@ namespace ICSharpCode.AvalonEdit.Document
 		{
 			VerifyNoUndoGroupOpen();
 			if (redostack.Count > 0) {
+				lastGroupDescriptor = null;
 				acceptChanges = false;
 				IUndoableOperation uedit = redostack.Pop();
 				undostack.Push(uedit);
@@ -195,6 +242,7 @@ namespace ICSharpCode.AvalonEdit.Document
 		{
 			VerifyNoUndoGroupOpen();
 			if (undostack.Count != 0) {
+				lastGroupDescriptor = null;
 				undostack.Clear();
 				NotifyPropertyChanged("CanUndo");
 			}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/FoldingMarginMarker.cs

@@ -38,6 +38,7 @@ namespace ICSharpCode.AvalonEdit.Gui
 			if (!e.Handled) {
 				if (e.ChangedButton == MouseButton.Left) {
 					IsExpanded = !IsExpanded;
+				e.Handled = true;
 				}
 			}
 		}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/SelectionMouseHandler.cs

@@ -164,8 +164,16 @@ namespace ICSharpCode.AvalonEdit.Gui
 							e.Effects = DragDropEffects.None;
 						} else {
 							Debug.WriteLine("Drop: insert at " + start);
-							textArea.Document.Insert(start, text);
-							textArea.Selection = new SimpleSelection(start, start + text.Length);
+							// Mark the undo group with the currentDragDescriptor, if the drag
+							// is originating from the same control. This allows combining
+							// the undo groups when text is moved.
+							textArea.Document.UndoStack.StartUndoGroup(this.currentDragDescriptor);
+							try {
+								textArea.Document.Insert(start, text);
+								textArea.Selection = new SimpleSelection(start, start + text.Length);
+							} finally {
+								textArea.Document.UndoStack.EndUndoGroup();
+							}
 						}
 					}
 				}
@@ -206,6 +214,8 @@ namespace ICSharpCode.AvalonEdit.Gui
 		#endregion
 		
 		#region Start Drag
+		object currentDragDescriptor;
+		
 		void StartDrag()
 		{
 			// prevent nested StartDrag calls
@@ -219,14 +229,21 @@ namespace ICSharpCode.AvalonEdit.Gui
 			dataObject.SetText(text);
 			
 			DragDropEffects allowedEffects = DragDropEffects.All;
-			List<AnchorSegment> deleteOnMove;
-			deleteOnMove = textArea.Selection.Segments.Select(s => new AnchorSegment(textArea.Document, s)).ToList();
+			var deleteOnMove = textArea.Selection.Segments.Select(s => new AnchorSegment(textArea.Document, s)).ToList();
+			
+			object dragDescriptor = new object();
+			this.currentDragDescriptor = dragDescriptor;
 			
 			Debug.WriteLine("DoDragDrop with allowedEffects=" + allowedEffects);
 			DragDropEffects resultEffect = DragDrop.DoDragDrop(textArea, dataObject, allowedEffects);
 			Debug.WriteLine("DoDragDrop done, resultEffect=" + resultEffect);
 			
+			this.currentDragDescriptor = null;
+			
 			if (deleteOnMove != null && resultEffect == DragDropEffects.Move) {
+				bool draggedInsideSingleDocument = (dragDescriptor == textArea.Document.UndoStack.LastGroupDescriptor);
+				if (draggedInsideSingleDocument)
+					textArea.Document.UndoStack.StartContinuedUndoGroup(null);
 				textArea.Document.BeginUpdate();
 				try {
 					foreach (ISegment s in deleteOnMove) {
@@ -234,6 +251,8 @@ namespace ICSharpCode.AvalonEdit.Gui
 					}
 				} finally {
 					textArea.Document.EndUpdate();
+					if (draggedInsideSingleDocument)
+						textArea.Document.UndoStack.EndUndoGroup();
 				}
 			}
 		}