[Gtk-sharp-list] Memory leak in tree cell func

[Matjaž Mihelič]

Same example as provided for gtk, except added empty method to handle
cell information and connected it in constructor.

Memory leak is constant on every call and more cells you use, more it
leaks. Easiest way to see it in action is simply resizing this window
for few seconds.

m.

// TreeModelSample.cs - TreeModelSample application.
//
// Author: Mike Kestner  <mkestner at novell.com>
//
// Copyright (c) 2007 Novell, Inc.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the Lesser GNU General 
// Public License as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the
// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.

namespace GtkSamples {

	using System;
	using System.Collections;
	using System.Reflection;
	using System.Runtime.InteropServices;
	using Gtk;

	public class TreeModelDemo : Gtk.Window {
		
		void test (TreeViewColumn tree_column, CellRenderer cell, TreeModel
tree_model, TreeIter iter)
		{
		}
		
		public TreeModelDemo () : base ("TreeModel demo")
		{
			DefaultSize = new Gdk.Size (640,480);
			ScrolledWindow sw = new ScrolledWindow ();
			TreeView view = new TreeView (new TreeModelAdapter (new MyTreeModel
()));
			view.HeadersVisible = true;
			CellRendererText cr1 = new CellRendererText ();
			CellRendererText cr2 = new CellRendererText ();
			view.AppendColumn ("Name", cr1, "text", 0);
			view.AppendColumn ("Type", cr2, "text", 1);
			view.Columns[0].SetCellDataFunc (cr1, new TreeCellDataFunc (test));
			view.Columns[1].SetCellDataFunc (cr2, new TreeCellDataFunc (test));
			sw.Add (view);
			sw.ShowAll ();
			Add (sw);
		}

		protected override bool OnDeleteEvent (Gdk.Event ev)
		{
			Application.Quit ();
			return true;
		}

		public static void Main (string[] args)
		{
			Application.Init ();
			Gtk.Window win = new TreeModelDemo ();	
			win.Show ();
			Application.Run ();
		}

	}

	public class MyTreeModel : GLib.Object, TreeModelImplementor {

		Assembly[] assemblies;

		public MyTreeModel ()
		{
			assemblies = AppDomain.CurrentDomain.GetAssemblies ();
		}

		object GetNodeAtPath (TreePath path)
		{
			if (path.Indices.Length > 0) {
				Assembly assm = assemblies [path.Indices [0]];
				if (path.Indices.Length > 1) {
					Type t = assm.GetTypes ()[path.Indices [1]];
					if (path.Indices.Length > 2)
						return t.GetMembers () [path.Indices [2]];
					else
						return t;
				} else
					return assm;
			} else
				return null;
		}

		Hashtable node_hash = new Hashtable ();

		public TreeModelFlags Flags {
			get {
				return TreeModelFlags.ItersPersist;
			}
		}

		public int NColumns {
			get {
				return 2;
			}
		}

		public GLib.GType GetColumnType (int col)
		{
			GLib.GType result = GLib.GType.String;
			return result;
		}

		TreeIter IterFromNode (object node)
		{
			GCHandle gch;
			if (node_hash [node] != null)
				gch = (GCHandle) node_hash [node];
			else
				gch = GCHandle.Alloc (node);
			TreeIter result = TreeIter.Zero;
			result.UserData = (IntPtr) gch;
			return result;
		}

		object NodeFromIter (TreeIter iter)
		{
			GCHandle gch = (GCHandle) iter.UserData;
			return gch.Target;
		}

		TreePath PathFromNode (object node)
		{
			if (node == null)
				return new TreePath ();

			object work = node;
			TreePath path = new TreePath ();

			if (work is MemberInfo) {
				Type parent = (work as MemberInfo).ReflectedType;
				path.PrependIndex (Array.IndexOf (parent.GetMembers (), work));
				work = parent;
			}
				
			if (work is Type) {
				Assembly assm = (work as Type).Assembly;
				path.PrependIndex (Array.IndexOf (assm.GetTypes (), work));
				work = assm;
			}

			if (work is Assembly)
				path.PrependIndex (Array.IndexOf (assemblies, node));
				
			return path;
		}

		public bool GetIter (out TreeIter iter, TreePath path)
		{
			if (path == null)
				throw new ArgumentNullException ("path");

			iter = TreeIter.Zero;

			object node = GetNodeAtPath (path);
			if (node == null)
				return false;

			iter = IterFromNode (node);
			return true;
		}

		public TreePath GetPath (TreeIter iter)
		{
			object node = NodeFromIter (iter);
			if (node == null) 
				throw new ArgumentException ("iter");

			return PathFromNode (node);
		}

		public void GetValue (TreeIter iter, int col, ref GLib.Value val)
		{
			object node = NodeFromIter (iter);
			if (node == null)
				return;

			if (node is Assembly)
				val = new GLib.Value (col == 0 ? (node as Assembly).GetName
().Name : "Assembly");
			else if (node is Type)
				val = new GLib.Value (col == 0 ? (node as Type).Name : "Type");
			else
				val = new GLib.Value (col == 0 ? (node as MemberInfo).Name :
"Member");
		}

		public bool IterNext (ref TreeIter iter)
		{
			object node = NodeFromIter (iter);
			if (node == null)
				return false;

			int idx;
			if (node is Assembly) {
				idx = Array.IndexOf (assemblies, node) + 1;
				if (idx < assemblies.Length) {
					iter = IterFromNode (assemblies [idx]);
					return true;
				}
			} else if (node is Type) {
				Type[] siblings = (node as Type).Assembly.GetTypes ();
				idx = Array.IndexOf (siblings, node) + 1;
				if (idx < siblings.Length) {
					iter = IterFromNode (siblings [idx]);
					return true;
				}
			} else {
				MemberInfo[] siblings = (node as
MemberInfo).ReflectedType.GetMembers ();
				idx = Array.IndexOf (siblings, node) + 1;
				if (idx < siblings.Length) {
					iter = IterFromNode (siblings [idx]);
					return true;
				}
			}
			return false;
		}

		int ChildCount (object node)
		{
			if (node is Assembly)
				return (node as Assembly).GetTypes ().Length;
			else if (node is Type)
				return (node as Type).GetMembers ().Length;
			else
				return 0;
		}

		public bool IterChildren (out TreeIter child, TreeIter parent)
		{
			child = TreeIter.Zero;

			if (parent.UserData == IntPtr.Zero) {
				child = IterFromNode (assemblies [0]);
				return true;
			}

			object node = NodeFromIter (parent);
			if (node == null || ChildCount (node) <= 0)
				return false;

			if (node is Assembly)
				child = IterFromNode ((node as Assembly).GetTypes () [0]);
			else if (node is Type)
				child = IterFromNode ((node as Type).GetMembers () [0]);
			return true;
		}

		public bool IterHasChild (TreeIter iter)
		{
			object node = NodeFromIter (iter);
			if (node == null || ChildCount (node) <= 0)
					return false;

			return true;
		}

		public int IterNChildren (TreeIter iter)
		{
			if (iter.UserData == IntPtr.Zero)
				return assemblies.Length;
				
			object node = NodeFromIter (iter);
			if (node == null)
				return 0;

			return ChildCount (node);
		}

		public bool IterNthChild (out TreeIter child, TreeIter parent, int n)
		{
			child = TreeIter.Zero;

			if (parent.UserData == IntPtr.Zero) {
				if (assemblies.Length <= n)
					return false;
				child = IterFromNode (assemblies [n]);
				return true;
			}
				
			object node = NodeFromIter (parent);
			if (node == null || ChildCount (node) <= n)
				return false;

			if (node is Assembly)
				child = IterFromNode ((node as Assembly).GetTypes () [n]);
			else if (node is Type)
				child = IterFromNode ((node as Type).GetMembers () [n]);
			return true;
		}

		public bool IterParent (out TreeIter parent, TreeIter child)
		{
			parent = TreeIter.Zero;
			object node = NodeFromIter (child);
			if (node == null || node is Assembly)
				return false;

			if (node is Type)
				parent = IterFromNode ((node as Type).Assembly);
			else if (node is MemberInfo)
				parent = IterFromNode ((node as MemberInfo).ReflectedType);
			return true;
		}

		public void RefNode (TreeIter iter)
		{
		}

		public void UnrefNode (TreeIter iter)
		{
		}
	}
}