NRefactory: Set parent of child when it is added to collection

lib/NRefactory/Project/NRefactory.csproj

@@ -54,6 +54,7 @@
     <None Include="Resources\ICSharpCode.NRefactory.snk" />
     <None Include="Src\Lexer\BuildKeywords.pl" />
     <Compile Include="Configuration\AssemblyInfo.cs" />
+    <Compile Include="Src\Ast\NodeCollection.cs" />
     <Compile Include="Src\Lexer\AbstractLexer.cs" />
     <Compile Include="Src\Lexer\CSharp\Keywords.cs" />
     <Compile Include="Src\Lexer\CSharp\Lexer.cs" />

lib/NRefactory/Project/Src/Ast/AbstractNode.cs

@@ -15,14 +15,20 @@ namespace ICSharpCode.NRefactory.Ast
 {
 	public abstract class AbstractNode : INode
 	{
-		IList<INode> children = new List<INode>();
+		NodeCollection children;
 		
 		public INode Parent { get; set; }
 		public Location StartLocation { get; set; }
 		public Location EndLocation { get; set; }
 		public object UserData { get; set; }
 		
-		public IList<INode> Children {
+		IList<INode> INode.Children {
+			get {
+				return children;
+			}
+		}
+		
+		public NodeCollection Children {
 			get {
 				return children;
 			}
@@ -32,6 +38,12 @@ namespace ICSharpCode.NRefactory.Ast
 			}
 		}
 		
+		public AbstractNode()
+		{
+			children = new NodeCollection();
+			children.Added += delegate(object sender, NodeEventArgs e) { e.Node.Parent = this; };
+		}
+		
 		public virtual void AddChild(INode childNode)
 		{
 			Debug.Assert(childNode != null);

lib/NRefactory/Project/Src/Ast/NodeCollection.cs

@@ -0,0 +1,99 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="David Srbecký" email="dsrbecky@gmail.com"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace ICSharpCode.NRefactory.Ast
+{
+	public class NodeCollection: Collection<INode>
+	{
+		public event EventHandler<NodeEventArgs> Added;
+		public event EventHandler<NodeEventArgs> Removed;
+		
+		protected virtual void OnAdded(NodeEventArgs e)
+		{
+			if (Added != null) {
+				Added(this, e);
+			}
+		}
+		
+		protected virtual void OnRemoved(NodeEventArgs e)
+		{
+			if (Removed != null) {
+				Removed(this, e);
+			}
+		}
+		
+		protected override void ClearItems()
+		{
+			while(this.Count > 0) {
+				this.RemoveFirst();
+			}
+		}
+		
+		protected override void InsertItem(int index, INode item)
+		{
+			base.InsertItem(index, item);
+			OnAdded(new NodeEventArgs(item));
+		}
+		
+		protected override void RemoveItem(int index)
+		{
+			INode removedNode = this[index];
+			base.RemoveItem(index);
+			OnRemoved(new NodeEventArgs(removedNode));
+		}
+		
+		protected override void SetItem(int index, INode item)
+		{
+			base.RemoveItem(index);
+			base.InsertItem(index, item);
+		}
+		
+		#region Convenience methods
+		
+		public INode First {
+			get {
+				return this[0];
+			}
+		}
+		
+		public INode Last {
+			get {
+				return this[this.Count - 1];
+			}
+		}
+		
+		public void RemoveFirst()
+		{
+			this.RemoveAt(0);
+		}
+		
+		public void RemoveLast()
+		{
+			this.RemoveAt(this.Count - 1);
+		}
+		
+		#endregion
+	}
+	
+	public class NodeEventArgs: EventArgs
+	{
+		INode inode;
+		
+		public INode Node {
+			get { return inode; }
+		}
+		
+		public NodeEventArgs(INode inode)
+		{
+			this.inode = inode;
+		}
+	}
+}