Enforce existing 5 action hardcoded undo limit.

This was present in the code but not enforced, which led to a memory leak over time as part properties were changed, whether by viewer, script or another source.
This commit enforces that limit, which will soon become configurable.
Regression test for undo limit added
Should help with http://opensimulator.org/mantis/view.php?id=6279

1 files changed, 33 insertions, 26 deletions

diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
index 63eb387..9e78242 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
@@ -266,8 +266,8 @@ namespace OpenSim.Region.Framework.Scenes
         private string m_sitAnimation = "SIT";
         private string m_text = String.Empty;
         private string m_touchName = String.Empty;
-        private readonly Stack<UndoState> m_undo = new Stack<UndoState>(5);
-        private readonly Stack<UndoState> m_redo = new Stack<UndoState>(5);
+        private readonly List<UndoState> m_undo = new List<UndoState>(5);
+        private readonly List<UndoState> m_redo = new List<UndoState>(5);
 
         private bool m_passTouches = false;
         private bool m_passCollisions = false;
@@ -3176,7 +3176,7 @@ namespace OpenSim.Region.Framework.Scenes
                         {
                             if (m_undo.Count > 0)
                             {
-                                UndoState last = m_undo.Peek();
+                                UndoState last = m_undo[m_undo.Count - 1];
                                 if (last != null)
                                 {
                                     // TODO: May need to fix for group comparison
@@ -3199,7 +3199,10 @@ namespace OpenSim.Region.Framework.Scenes
                             {
                                 UndoState nUndo = new UndoState(this, forGroup);
     
-                                m_undo.Push(nUndo);
+                                m_undo.Add(nUndo);
+
+                                if (m_undo.Count > ParentGroup.GetSceneMaxUndo())
+                                    m_undo.RemoveAt(0);
     
                                 if (m_redo.Count > 0)
                                     m_redo.Clear();
@@ -3245,21 +3248,24 @@ namespace OpenSim.Region.Framework.Scenes
 
                 if (m_undo.Count > 0)
                 {
-                    UndoState goback = m_undo.Pop();
+                    UndoState goback = m_undo[m_undo.Count - 1];
+                    m_undo.RemoveAt(m_undo.Count - 1);
 
-                    if (goback != null)
+                    UndoState nUndo = null;
+    
+                    if (ParentGroup.GetSceneMaxUndo() > 0)
                     {
-                        UndoState nUndo = null;
-        
-                        if (ParentGroup.GetSceneMaxUndo() > 0)
-                        {
-                            nUndo = new UndoState(this, goback.ForGroup);
-                        }
+                        nUndo = new UndoState(this, goback.ForGroup);
+                    }
+
+                    goback.PlaybackState(this);
 
-                        goback.PlaybackState(this);
+                    if (nUndo != null)
+                    {
+                        m_redo.Add(nUndo);
 
-                        if (nUndo != null)
-                            m_redo.Push(nUndo);
+                        if (m_redo.Count > ParentGroup.GetSceneMaxUndo())
+                            m_redo.RemoveAt(0);
                     }
                 }
 
@@ -3279,20 +3285,21 @@ namespace OpenSim.Region.Framework.Scenes
 
                 if (m_redo.Count > 0)
                 {
-                    UndoState gofwd = m_redo.Pop();
-    
-                    if (gofwd != null)
+                    UndoState gofwd = m_redo[m_redo.Count - 1];
+                    m_redo.RemoveAt(m_redo.Count - 1);
+
+                    if (ParentGroup.GetSceneMaxUndo() > 0)
                     {
-                        if (ParentGroup.GetSceneMaxUndo() > 0)
-                        {
-                            UndoState nUndo = new UndoState(this, gofwd.ForGroup);
-    
-                            m_undo.Push(nUndo);
-                        }
-    
-                        gofwd.PlayfwdState(this);
+                        UndoState nUndo = new UndoState(this, gofwd.ForGroup);
+
+                        m_undo.Add(nUndo);
+
+                        if (m_undo.Count > ParentGroup.GetSceneMaxUndo())
+                            m_undo.RemoveAt(0);
                     }
 
+                    gofwd.PlayfwdState(this);
+
 //                m_log.DebugFormat(
 //                    "[SCENE OBJECT PART]: Handled redo request for {0} {1}, stack size now {2}",
 //                    Name, LocalId, m_redo.Count);