1 files changed, 619 insertions, 250 deletions

diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs b/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
index 1ca390a..7053c02 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
@@ -104,8 +104,95 @@ namespace OpenSim.Region.Framework.Scenes
         /// since the group's last persistent backup
         /// </summary>
         private bool m_hasGroupChanged = false;
-        private long timeFirstChanged;
-        private long timeLastChanged;
+        private long timeFirstChanged = 0;
+        private long timeLastChanged = 0;
+        private long m_maxPersistTime = 0;
+        private long m_minPersistTime = 0;
+        private Random m_rand;
+        private bool m_suspendUpdates;
+        private System.Threading.ReaderWriterLockSlim m_partsLock = new System.Threading.ReaderWriterLockSlim();        
+        private List<ScenePresence> m_linkedAvatars = new List<ScenePresence>();
+
+        public bool areUpdatesSuspended
+        {
+            get
+            {
+                return m_suspendUpdates;
+            }
+            set 
+            {
+                m_suspendUpdates = value;   
+                if (!value)
+                {
+                    QueueForUpdateCheck();
+                }               
+            }
+        }
+
+        public void lockPartsForRead(bool locked)
+        {
+            if (locked)
+            {
+                if (m_partsLock.RecursiveReadCount > 0)
+                {
+                    m_log.Error("[SceneObjectGroup.m_parts] Recursive read lock requested. This should not happen and means something needs to be fixed. For now though, it's safe to continue.");
+                    m_partsLock.ExitReadLock();
+                }
+                if (m_partsLock.RecursiveWriteCount > 0)
+                {
+                    m_log.Error("[SceneObjectGroup.m_parts] Recursive read lock requested (write lock exists on this thread). This should not happen and means something needs to be fixed.");
+                    m_partsLock.ExitWriteLock();
+                }
+
+                while (!m_partsLock.TryEnterReadLock(60000))
+                {
+                    m_log.Error("[SceneObjectGroup.m_parts] Thread lock detected while trying to aquire READ lock of m_parts in SceneObjectGroup. I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+                    if (m_partsLock.IsWriteLockHeld)
+                    {
+                        m_partsLock = new System.Threading.ReaderWriterLockSlim();
+                    }
+                }
+            }
+            else
+            {
+                if (m_partsLock.RecursiveReadCount > 0)
+                {
+                    m_partsLock.ExitReadLock();
+                }
+            }
+        }
+        public void lockPartsForWrite(bool locked)
+        {
+            if (locked)
+            {
+                if (m_partsLock.RecursiveReadCount > 0)
+                {
+                    m_log.Error("[SceneObjectGroup.m_parts] Recursive write lock requested. This should not happen and means something needs to be fixed. For now though, it's safe to continue.");
+                    m_partsLock.ExitReadLock();
+                }
+                if (m_partsLock.RecursiveWriteCount > 0)
+                {
+                    m_log.Error("[SceneObjectGroup.m_parts] Recursive write lock requested. This should not happen and means something needs to be fixed.");
+                    m_partsLock.ExitWriteLock();
+                }
+
+                while (!m_partsLock.TryEnterWriteLock(60000))
+                {
+                    m_log.Error("[SceneObjectGroup.m_parts] Thread lock detected while trying to aquire WRITE lock of m_scripts in XEngine. I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+                    if (m_partsLock.IsWriteLockHeld)
+                    {
+                        m_partsLock = new System.Threading.ReaderWriterLockSlim();
+                    }
+                }
+            }
+            else
+            {
+                if (m_partsLock.RecursiveWriteCount > 0)
+                {
+                    m_partsLock.ExitWriteLock();
+                }
+            }
+        }
 
         public bool HasGroupChanged
         {
@@ -113,9 +200,39 @@ namespace OpenSim.Region.Framework.Scenes
             {
                 if (value)
                 {
+                    if (m_isBackedUp)
+                    {
+                        m_scene.SceneGraph.FireChangeBackup(this);
+                    }
                     timeLastChanged = DateTime.Now.Ticks;
                     if (!m_hasGroupChanged)
                         timeFirstChanged = DateTime.Now.Ticks;
+                    if (m_rootPart != null && m_rootPart.UUID != null && m_scene != null)
+                    {
+                        if (m_rand == null)
+                        {
+                            byte[] val = new byte[16];
+                            m_rootPart.UUID.ToBytes(val, 0);
+                            m_rand = new Random(BitConverter.ToInt32(val, 0));
+                        }
+                       
+                        if (m_scene.GetRootAgentCount() == 0)
+                        {
+                            //If the region is empty, this change has been made by an automated process
+                            //and thus we delay the persist time by a random amount between 1.5 and 2.5.
+
+                            float factor = 1.5f + (float)(m_rand.NextDouble());
+                            m_maxPersistTime = (long)((float)m_scene.m_persistAfter * factor);
+                            m_minPersistTime = (long)((float)m_scene.m_dontPersistBefore * factor);
+                        }
+                        else
+                        {
+                            //If the region is not empty, we want to obey the minimum and maximum persist times
+                            //but add a random factor so we stagger the object persistance a little
+                            m_maxPersistTime = (long)((float)m_scene.m_persistAfter * (1.0d - (m_rand.NextDouble() / 5.0d))); //Multiply by 1.0-1.5
+                            m_minPersistTime = (long)((float)m_scene.m_dontPersistBefore * (1.0d + (m_rand.NextDouble() / 2.0d))); //Multiply by 0.8-1.0
+                        }
+                    }
                 }
                 m_hasGroupChanged = value;
             }
@@ -131,8 +248,19 @@ namespace OpenSim.Region.Framework.Scenes
                 return false;
             if (m_scene.ShuttingDown)
                 return true;
+
+            if (m_minPersistTime == 0 || m_maxPersistTime == 0)
+            {
+                m_maxPersistTime = m_scene.m_persistAfter;
+                m_minPersistTime = m_scene.m_dontPersistBefore;
+            }
+                
             long currentTime = DateTime.Now.Ticks;
-            if (currentTime - timeLastChanged > m_scene.m_dontPersistBefore || currentTime - timeFirstChanged > m_scene.m_persistAfter)
+
+            if (timeLastChanged == 0) timeLastChanged = currentTime;
+            if (timeFirstChanged == 0) timeFirstChanged = currentTime;
+
+            if (currentTime - timeLastChanged > m_minPersistTime || currentTime - timeFirstChanged > m_maxPersistTime)
                 return true;
             return false;
         }
@@ -221,7 +349,21 @@ namespace OpenSim.Region.Framework.Scenes
         public virtual Quaternion Rotation
         {
             get { return m_rotation; }
-            set { m_rotation = value; }
+            set {
+                lockPartsForRead(true);
+                try
+                {
+                    foreach(SceneObjectPart p in m_parts.Values)
+                    {
+                        p.StoreUndoState(UndoType.STATE_GROUP_ROTATION);
+                    }
+                }
+                finally
+                {
+                    lockPartsForRead(false);
+                }
+                m_rotation = value; 
+            }
         }
 
         public Quaternion GroupRotation
@@ -258,13 +400,16 @@ namespace OpenSim.Region.Framework.Scenes
             set
             {
                 m_regionHandle = value;
-                lock (m_parts)
+                lockPartsForRead(true);
                 {
                     foreach (SceneObjectPart part in m_parts.Values)
                     {
+                        
                         part.RegionHandle = m_regionHandle;
+                        
                     }
                 }
+                lockPartsForRead(false);
             }
         }
 
@@ -298,6 +443,12 @@ namespace OpenSim.Region.Framework.Scenes
                 {
                     m_scene.CrossPrimGroupIntoNewRegion(val, this, true);
                 }
+
+                lockPartsForRead(true);
+                foreach (SceneObjectPart part in m_parts.Values)
+                {
+                    part.IgnoreUndoUpdate = true;
+                }
                 if (RootPart.GetStatusSandbox())
                 {
                     if (Util.GetDistanceTo(RootPart.StatusSandboxPos, value) > 10)
@@ -305,16 +456,17 @@ namespace OpenSim.Region.Framework.Scenes
                         RootPart.ScriptSetPhysicsStatus(false);
                         Scene.SimChat(Utils.StringToBytes("Hit Sandbox Limit"),
                               ChatTypeEnum.DebugChannel, 0x7FFFFFFF, RootPart.AbsolutePosition, Name, UUID, false);
+                        lockPartsForRead(false);
                         return;
                     }
                 }
-                lock (m_parts)
+                foreach (SceneObjectPart part in m_parts.Values)
                 {
-                    foreach (SceneObjectPart part in m_parts.Values)
-                    {
-                        part.GroupPosition = val;
-                    }
+                    part.IgnoreUndoUpdate = false;
+                    part.StoreUndoState(UndoType.STATE_GROUP_POSITION);
+                    part.GroupPosition = val;
                 }
+                lockPartsForRead(false);
 
                 //if (m_rootPart.PhysActor != null)
                 //{
@@ -457,6 +609,7 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public SceneObjectGroup()
         {
+            
         }
 
         /// <summary>
@@ -473,7 +626,7 @@ namespace OpenSim.Region.Framework.Scenes
         /// Constructor.  This object is added to the scene later via AttachToScene()
         /// </summary>
         public SceneObjectGroup(UUID ownerID, Vector3 pos, Quaternion rot, PrimitiveBaseShape shape)
-        { 
+        {
             SetRootPart(new SceneObjectPart(ownerID, shape, pos, rot, Vector3.Zero));
         }
 
@@ -504,13 +657,16 @@ namespace OpenSim.Region.Framework.Scenes
 
         public void SetFromItemID(UUID AssetId)
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     part.FromItemID = AssetId;
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         public UUID GetFromItemID()
@@ -523,6 +679,9 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public virtual void AttachToBackup()
         {
+            if (IsAttachment) return;
+            m_scene.SceneGraph.FireAttachToBackup(this);
+
             if (InSceneBackup)
             {
                 //m_log.DebugFormat(
@@ -579,7 +738,7 @@ namespace OpenSim.Region.Framework.Scenes
             Vector3 maxScale = Vector3.Zero;
             Vector3 finalScale = new Vector3(0.5f, 0.5f, 0.5f);
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
@@ -593,8 +752,11 @@ namespace OpenSim.Region.Framework.Scenes
                     maxScale.X = (partscale.X + partoffset.X > maxScale.X) ? partscale.X + partoffset.X : maxScale.X;
                     maxScale.Y = (partscale.Y + partoffset.Y > maxScale.Y) ? partscale.Y + partoffset.Y : maxScale.Y;
                     maxScale.Z = (partscale.Z + partoffset.Z > maxScale.Z) ? partscale.Z + partoffset.Z : maxScale.Z;
+                    
                 }
             }
+            lockPartsForRead(false);
+
             finalScale.X = (minScale.X > maxScale.X) ? minScale.X : maxScale.X;
             finalScale.Y = (minScale.Y > maxScale.Y) ? minScale.Y : maxScale.Y;
             finalScale.Z = (minScale.Z > maxScale.Z) ? minScale.Z : maxScale.Z;
@@ -610,10 +772,11 @@ namespace OpenSim.Region.Framework.Scenes
 
             EntityIntersection result = new EntityIntersection();
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     // Temporary commented to stop compiler warning
                     //Vector3 partPosition =
                     //    new Vector3(part.AbsolutePosition.X, part.AbsolutePosition.Y, part.AbsolutePosition.Z);
@@ -641,8 +804,10 @@ namespace OpenSim.Region.Framework.Scenes
                             result.distance = inter.distance;
                         }
                     }
+                    
                 }
             }
+            lockPartsForRead(false);
             return result;
         }
 
@@ -661,10 +826,11 @@ namespace OpenSim.Region.Framework.Scenes
             minY = 256f;
             minZ = 8192f;
 
-            lock(m_parts);
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     Vector3 worldPos = part.GetWorldPosition();
                     Vector3 offset = worldPos - AbsolutePosition;
                     Quaternion worldRot;
@@ -723,6 +889,8 @@ namespace OpenSim.Region.Framework.Scenes
                     backBottomRight.Y = orig.Y + (part.Scale.Y / 2);
                     backBottomRight.Z = orig.Z - (part.Scale.Z / 2);
 
+                    
+
                     //m_log.InfoFormat("pre corner 1 is {0} {1} {2}", frontTopLeft.X, frontTopLeft.Y, frontTopLeft.Z);
                     //m_log.InfoFormat("pre corner 2 is {0} {1} {2}", frontTopRight.X, frontTopRight.Y, frontTopRight.Z);
                     //m_log.InfoFormat("pre corner 3 is {0} {1} {2}", frontBottomRight.X, frontBottomRight.Y, frontBottomRight.Z);
@@ -894,6 +1062,7 @@ namespace OpenSim.Region.Framework.Scenes
                         minZ = backBottomLeft.Z;
                 }
             }
+            lockPartsForRead(false);
         }
 
         public Vector3 GetAxisAlignedBoundingBox(out float offsetHeight)
@@ -929,21 +1098,29 @@ namespace OpenSim.Region.Framework.Scenes
 
         public void SaveScriptedState(XmlTextWriter writer)
         {
+            SaveScriptedState(writer, false);
+        }
+
+        public void SaveScriptedState(XmlTextWriter writer, bool oldIDs)
+        {
             XmlDocument doc = new XmlDocument();
             Dictionary<UUID,string> states = new Dictionary<UUID,string>();
 
             // Capture script state while holding the lock
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
-                    Dictionary<UUID,string> pstates = part.Inventory.GetScriptStates();
+                    
+                    Dictionary<UUID,string> pstates = part.Inventory.GetScriptStates(oldIDs);
                     foreach (UUID itemid in pstates.Keys)
                     {
                         states.Add(itemid, pstates[itemid]);
                     }
+                    
                 }
             }
+            lockPartsForRead(false);
 
             if (states.Count > 0)
             {
@@ -962,6 +1139,47 @@ namespace OpenSim.Region.Framework.Scenes
         }
 
         /// <summary>
+        /// Add the avatar to this linkset (avatar is sat).
+        /// </summary>
+        /// <param name="agentID"></param>
+        public void AddAvatar(UUID agentID)
+        {
+            ScenePresence presence;
+            if (m_scene.TryGetScenePresence(agentID, out presence))
+            {
+                if (!m_linkedAvatars.Contains(presence))
+                {
+                    m_linkedAvatars.Add(presence);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Delete the avatar from this linkset (avatar is unsat).
+        /// </summary>
+        /// <param name="agentID"></param>
+        public void DeleteAvatar(UUID agentID)
+        {
+            ScenePresence presence;
+            if (m_scene.TryGetScenePresence(agentID, out presence))
+            {
+                if (m_linkedAvatars.Contains(presence))
+                {
+                    m_linkedAvatars.Remove(presence);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Returns the list of linked presences (avatars sat on this group)
+        /// </summary>
+        /// <param name="agentID"></param>
+        public List<ScenePresence> GetLinkedAvatars()
+        {
+            return m_linkedAvatars;
+        }
+
+        /// <summary>
         /// Attach this scene object to the given avatar.
         /// </summary>
         /// <param name="agentID"></param>
@@ -1112,13 +1330,16 @@ namespace OpenSim.Region.Framework.Scenes
 
         public override void UpdateMovement()
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     part.UpdateMovement();
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         public ushort GetTimeDilation()
@@ -1162,7 +1383,7 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="part"></param>
         public void AddPart(SceneObjectPart part)
         {
-            lock (m_parts)
+            lockPartsForWrite(true);
             {
                 part.SetParent(this);
                 m_parts.Add(part.UUID, part);
@@ -1172,6 +1393,7 @@ namespace OpenSim.Region.Framework.Scenes
                 if (part.LinkNum == 2 && RootPart != null)
                     RootPart.LinkNum = 1;
             }
+            lockPartsForWrite(false);
         }
 
         /// <summary>
@@ -1179,28 +1401,33 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         private void UpdateParentIDs()
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     if (part.UUID != m_rootPart.UUID)
                     {
                         part.ParentID = m_rootPart.LocalId;
                     }
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         public void RegenerateFullIDs()
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     part.UUID = UUID.Random();
-
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         // helper provided for parts.
@@ -1261,7 +1488,7 @@ namespace OpenSim.Region.Framework.Scenes
 
         public virtual void OnGrabPart(SceneObjectPart part, Vector3 offsetPos, IClientAPI remoteClient)
         {
-            part.StoreUndoState();
+            part.StoreUndoState(UndoType.STATE_PRIM_ALL);
             part.OnGrab(offsetPos, remoteClient);
         }
 
@@ -1281,27 +1508,32 @@ namespace OpenSim.Region.Framework.Scenes
 
             DetachFromBackup();
 
-            lock (m_parts)
+            lockPartsForRead(true);
+            List<SceneObjectPart> values = new List<SceneObjectPart>(m_parts.Values);
+            lockPartsForRead(false);
+            
+            foreach (SceneObjectPart part in values)
             {
-                foreach (SceneObjectPart part in m_parts.Values)
-                {
 //                    part.Inventory.RemoveScriptInstances();
-                    Scene.ForEachScenePresence(delegate(ScenePresence avatar)
+                
+                Scene.ForEachScenePresence(delegate (ScenePresence sp)
+                {
+                    if (sp.ParentID == LocalId)
                     {
-                        if (avatar.ParentID == LocalId)
-                        {
-                            avatar.StandUp();
-                        }
+                        sp.StandUp();
+                    }
 
-                        if (!silent)
-                        {
-                            part.UpdateFlag = 0;
-                            if (part == m_rootPart)
-                                avatar.ControllingClient.SendKillObject(m_regionHandle, part.LocalId);
-                        }
-                    });
-                }
+                    if (!silent)
+                    {
+                        part.UpdateFlag = 0;
+                        if (part == m_rootPart)
+                            sp.ControllingClient.SendKillObject(m_regionHandle, part.LocalId);
+                    }
+                });
+                
             }
+            
+          
         }
 
         public void AddScriptLPS(int count)
@@ -1326,17 +1558,20 @@ namespace OpenSim.Region.Framework.Scenes
 
             scriptEvents aggregateScriptEvents=0;
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     if (part == null)
                         continue;
                     if (part != RootPart)
                         part.ObjectFlags = objectflagupdate;
                     aggregateScriptEvents |= part.AggregateScriptEvents;
+                    
                 }
             }
+            lockPartsForRead(false);
 
             m_scriptListens_atTarget = ((aggregateScriptEvents & scriptEvents.at_target) != 0);
             m_scriptListens_notAtTarget = ((aggregateScriptEvents & scriptEvents.not_at_target) != 0);
@@ -1378,42 +1613,52 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="m_physicalPrim"></param>
         public void ApplyPhysics(bool m_physicalPrim)
         {
-            lock (m_parts)
+            lockPartsForRead(true);
+            
+            if (m_parts.Count > 1)
             {
-                if (m_parts.Count > 1)
+                List<SceneObjectPart> values = new List<SceneObjectPart>(m_parts.Values);
+                lockPartsForRead(false);
+                m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive, m_physicalPrim);
+                foreach (SceneObjectPart part in values)
                 {
-                    m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive, m_physicalPrim);
-                    foreach (SceneObjectPart part in m_parts.Values)
+                    
+                    if (part.LocalId != m_rootPart.LocalId)
                     {
-                        if (part.LocalId != m_rootPart.LocalId)
-                        {
-                            part.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), part.VolumeDetectActive, m_physicalPrim);
-                        }
+                        part.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), part.VolumeDetectActive, m_physicalPrim);
                     }
                     
-                    // Hack to get the physics scene geometries in the right spot
-                    ResetChildPrimPhysicsPositions();
-                }
-                else
-                {
-                    m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive, m_physicalPrim);
                 }
+                // Hack to get the physics scene geometries in the right spot
+                ResetChildPrimPhysicsPositions();
+            }
+            else
+            {
+                lockPartsForRead(false);
+                m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive, m_physicalPrim);
             }
         }
 
         public void SetOwnerId(UUID userId)
         {
-            ForEachPart(delegate(SceneObjectPart part) { part.OwnerID = userId; });
+                ForEachPart(delegate(SceneObjectPart part) 
+                {
+                    
+                    part.OwnerID = userId;
+                    
+                });
         }
 
         public void ForEachPart(Action<SceneObjectPart> whatToDo)
         {
-            lock (m_parts)
+            lockPartsForRead(true);
+            List<SceneObjectPart> values = new List<SceneObjectPart>(m_parts.Values);
+            lockPartsForRead(false);    
+            foreach (SceneObjectPart part in values)
             {
-                foreach (SceneObjectPart part in m_parts.Values)
-                {
-                    whatToDo(part);
-                }
+                
+                whatToDo(part);
+                
             }
         }
 
@@ -1511,15 +1756,17 @@ namespace OpenSim.Region.Framework.Scenes
             RootPart.SendFullUpdate(
                 remoteClient, m_scene.Permissions.GenerateClientFlags(remoteClient.AgentId, RootPart.UUID));
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     if (part != RootPart)
                         part.SendFullUpdate(
                             remoteClient, m_scene.Permissions.GenerateClientFlags(remoteClient.AgentId, part.UUID));
                 }
             }
+            lockPartsForRead(false);
         }
 
         #region Copying
@@ -1580,10 +1827,11 @@ namespace OpenSim.Region.Framework.Scenes
 
             List<SceneObjectPart> partList;
 
-            lock (m_parts)
-            {
-                partList = new List<SceneObjectPart>(m_parts.Values);
-            }
+            lockPartsForRead(true);
+            
+            partList = new List<SceneObjectPart>(m_parts.Values);
+            
+            lockPartsForRead(false);
             
             partList.Sort(delegate(SceneObjectPart p1, SceneObjectPart p2)
                 {
@@ -1800,13 +2048,40 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
         
+        public void rotLookAt(Quaternion target, float strength, float damping)
+        {
+            SceneObjectPart rootpart = m_rootPart;
+            if (rootpart != null)
+            {
+                if (IsAttachment)
+                {
+                /*
+                    ScenePresence avatar = m_scene.GetScenePresence(rootpart.AttachedAvatar);
+                    if (avatar != null)
+                    {
+                    Rotate the Av?
+                    } */
+                }
+                else
+                {
+                    if (rootpart.PhysActor != null)
+                    {                                                                   // APID must be implemented in your physics system for this to function.
+                        rootpart.PhysActor.APIDTarget = new Quaternion(target.X, target.Y, target.Z, target.W);
+                        rootpart.PhysActor.APIDStrength = strength;
+                        rootpart.PhysActor.APIDDamping = damping;
+                        rootpart.PhysActor.APIDActive = true;
+                    }
+                }
+            }
+        }
+
         public void stopLookAt()
         {
             SceneObjectPart rootpart = m_rootPart;
             if (rootpart != null)
             {
                 if (rootpart.PhysActor != null)
-                {
+                {                                                       // APID must be implemented in your physics system for this to function.
                     rootpart.PhysActor.APIDActive = false;
                 }
             }
@@ -1874,10 +2149,11 @@ namespace OpenSim.Region.Framework.Scenes
             SceneObjectPart newPart = part.Copy(m_scene.AllocateLocalId(), OwnerID, GroupID, m_parts.Count, userExposed);
             newPart.SetParent(this);
 
-            lock (m_parts)
+            lockPartsForWrite(true);
             {
                 m_parts.Add(newPart.UUID, newPart);
             }
+            lockPartsForWrite(false);
 
             SetPartAsNonRoot(newPart);
 
@@ -1940,7 +2216,7 @@ namespace OpenSim.Region.Framework.Scenes
             //if ((RootPart.Flags & PrimFlags.TemporaryOnRez) != 0)
             //    return;
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 bool UsePhysics = ((RootPart.Flags & PrimFlags.Physics) != 0);
 
@@ -1960,9 +2236,12 @@ namespace OpenSim.Region.Framework.Scenes
                 {
                     if (!IsSelected)
                         part.UpdateLookAt();
+
                     part.SendScheduledUpdates();
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         public void ScheduleFullUpdateToAvatar(ScenePresence presence)
@@ -1971,27 +2250,29 @@ namespace OpenSim.Region.Framework.Scenes
             
             RootPart.AddFullUpdateToAvatar(presence);
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     if (part != RootPart)
                         part.AddFullUpdateToAvatar(presence);
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         public void ScheduleTerseUpdateToAvatar(ScenePresence presence)
         {
-//            m_log.DebugFormat("[SOG]: Scheduling terse update for {0} {1} just to avatar {2}", Name, UUID, presence.Name);
-            
-            lock (m_parts)
+            lockPartsForRead(true);
+
+            foreach (SceneObjectPart part in m_parts.Values)
             {
-                foreach (SceneObjectPart part in m_parts.Values)
-                {
-                    part.AddTerseUpdateToAvatar(presence);
-                }
+                part.AddTerseUpdateToAvatar(presence);
             }
+
+            lockPartsForRead(false);
         }
 
         /// <summary>
@@ -1999,20 +2280,23 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public void ScheduleGroupForFullUpdate()
         {
-            if (IsAttachment)
-                m_log.DebugFormat("[SOG]: Scheduling full update for {0} {1}", Name, LocalId);
+            //if (IsAttachment)
+               // m_log.DebugFormat("[SOG]: Scheduling full update for {0} {1}", Name, LocalId);
             
             checkAtTargets();
             RootPart.ScheduleFullUpdate();
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     if (part != RootPart)
                         part.ScheduleFullUpdate();
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         /// <summary>
@@ -2020,37 +2304,38 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public void ScheduleGroupForTerseUpdate()
         {
-//            m_log.DebugFormat("[SOG]: Scheduling terse update for {0} {1}", Name, UUID);
-            
-            lock (m_parts)
+            lockPartsForRead(true);
+            foreach (SceneObjectPart part in m_parts.Values)
             {
-                foreach (SceneObjectPart part in m_parts.Values)
-                {
-                    part.ScheduleTerseUpdate();
-                }
+                part.ScheduleTerseUpdate();
             }
+
+            lockPartsForRead(false);
         }
 
         /// <summary>
         /// Immediately send a full update for this scene object.
         /// </summary>
         public void SendGroupFullUpdate()
-        {
+        {                       
             if (IsDeleted)
                 return;
 
-//            m_log.DebugFormat("[SOG]: Sending immediate full group update for {0} {1}", Name, UUID);
+//            m_log.DebugFormat("[SOG]: Sending immediate full group update for {0} {1}", Name, UUID);            
             
             RootPart.SendFullUpdateToAllClients();
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
+                    
                     if (part != RootPart)
                         part.SendFullUpdateToAllClients();
+                    
                 }
             }
+            lockPartsForRead(false);
         }
 
         /// <summary>
@@ -2082,14 +2367,15 @@ namespace OpenSim.Region.Framework.Scenes
         {
             if (IsDeleted)
                 return;
-            
-            lock (m_parts)
+
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
                     part.SendTerseUpdateToAllClients();
                 }
             }
+            lockPartsForRead(false);
         }
 
         #endregion
@@ -2103,16 +2389,18 @@ namespace OpenSim.Region.Framework.Scenes
         /// <returns>null if no child part with that linknum or child part</returns>
         public SceneObjectPart GetLinkNumPart(int linknum)
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
                     if (part.LinkNum == linknum)
                     {
+                        lockPartsForRead(false);
                         return part;
                     }
                 }
             }
+            lockPartsForRead(false);
 
             return null;
         }
@@ -2140,17 +2428,19 @@ namespace OpenSim.Region.Framework.Scenes
         public SceneObjectPart GetChildPart(uint localID)
         {
             //m_log.DebugFormat("Entered looking for {0}", localID);
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
                     //m_log.DebugFormat("Found {0}", part.LocalId);
                     if (part.LocalId == localID)
                     {
+                        lockPartsForRead(false);
                         return part;
                     }
                 }
             }
+            lockPartsForRead(false);
 
             return null;
         }
@@ -2180,17 +2470,19 @@ namespace OpenSim.Region.Framework.Scenes
         public bool HasChildPrim(uint localID)
         {
             //m_log.DebugFormat("Entered HasChildPrim looking for {0}", localID);
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
                     //m_log.DebugFormat("Found {0}", part.LocalId);
                     if (part.LocalId == localID)
                     {
+                        lockPartsForRead(false);
                         return true;
                     }
                 }
             }
+            lockPartsForRead(false);
 
             return false;
         }
@@ -2240,53 +2532,57 @@ namespace OpenSim.Region.Framework.Scenes
             if (m_rootPart.LinkNum == 0)
                 m_rootPart.LinkNum = 1;
 
-            lock (m_parts)
-            {
-                m_parts.Add(linkPart.UUID, linkPart);
+            lockPartsForWrite(true);
+            
+            m_parts.Add(linkPart.UUID, linkPart);
+
+            lockPartsForWrite(false);
 
-                // Insert in terms of link numbers, the new links
-                // before the current ones (with the exception of 
-                // the root prim. Shuffle the old ones up
-                foreach (KeyValuePair<UUID, SceneObjectPart> kvp in m_parts) 
+            // Insert in terms of link numbers, the new links
+            // before the current ones (with the exception of 
+            // the root prim. Shuffle the old ones up
+            lockPartsForRead(true);
+            foreach (KeyValuePair<UUID, SceneObjectPart> kvp in m_parts) 
+            {
+                if (kvp.Value.LinkNum != 1)
                 {
-                    if (kvp.Value.LinkNum != 1)
-                    {
-                        // Don't update root prim link number
-                        kvp.Value.LinkNum += objectGroup.PrimCount;
-                    }
+                    // Don't update root prim link number
+                    kvp.Value.LinkNum += objectGroup.PrimCount;
                 }
+            }
+            lockPartsForRead(false);
 
-                linkPart.LinkNum = 2;
+            linkPart.LinkNum = 2;
 
-                linkPart.SetParent(this);
-                linkPart.CreateSelected = true;
+            linkPart.SetParent(this);
+            linkPart.CreateSelected = true;
 
-                //if (linkPart.PhysActor != null)
-                //{
-                // m_scene.PhysicsScene.RemovePrim(linkPart.PhysActor);
-        
-                //linkPart.PhysActor = null;
-                //}
+            //if (linkPart.PhysActor != null)
+            //{
+            // m_scene.PhysicsScene.RemovePrim(linkPart.PhysActor);
+    
+            //linkPart.PhysActor = null;
+            //}
 
-                //TODO: rest of parts
-                int linkNum = 3;
-                foreach (SceneObjectPart part in objectGroup.Children.Values)
+            //TODO: rest of parts
+            int linkNum = 3;
+            foreach (SceneObjectPart part in objectGroup.Children.Values)
+            {
+                if (part.UUID != objectGroup.m_rootPart.UUID)
                 {
-                    if (part.UUID != objectGroup.m_rootPart.UUID)
-                    {
-                        LinkNonRootPart(part, oldGroupPosition, oldRootRotation, linkNum++);
-                    }
-                    part.ClearUndoState();
+                    LinkNonRootPart(part, oldGroupPosition, oldRootRotation, linkNum++);
                 }
+                part.ClearUndoState();
             }
 
             m_scene.UnlinkSceneObject(objectGroup.UUID, true);
             objectGroup.m_isDeleted = true;
+
+            objectGroup.lockPartsForWrite(true);
             
-            lock (objectGroup.m_parts)
-            {
-                objectGroup.m_parts.Clear();
-            }
+            objectGroup.m_parts.Clear();
+            
+            objectGroup.lockPartsForWrite(false);
             
             // Can't do this yet since backup still makes use of the root part without any synchronization
 //            objectGroup.m_rootPart = null;
@@ -2356,11 +2652,12 @@ namespace OpenSim.Region.Framework.Scenes
             Quaternion worldRot = linkPart.GetWorldRotation();
 
             // Remove the part from this object
-            lock (m_parts)
+            lockPartsForWrite(true);
             {
                 m_parts.Remove(linkPart.UUID);
             }
-
+            lockPartsForWrite(false);
+            lockPartsForRead(true);
             if (m_parts.Count == 1 && RootPart != null) //Single prim is left
                 RootPart.LinkNum = 0;
             else
@@ -2371,6 +2668,7 @@ namespace OpenSim.Region.Framework.Scenes
                         p.LinkNum--;
                 }
             }
+            lockPartsForRead(false);
 
             linkPart.ParentID = 0;
             linkPart.LinkNum = 0;
@@ -2414,6 +2712,8 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="objectGroup"></param>
         public virtual void DetachFromBackup()
         {
+            m_scene.SceneGraph.FireDetachFromBackup(this);
+
             if (m_isBackedUp)
                 m_scene.EventManager.OnBackup -= ProcessBackup;
             
@@ -2692,9 +2992,12 @@ namespace OpenSim.Region.Framework.Scenes
 
             if (selectionPart != null)
             {
-                lock (m_parts)
+                lockPartsForRead(true);
+                List<SceneObjectPart> parts = new List<SceneObjectPart>(m_parts.Values);
+                lockPartsForRead(false);
+                foreach (SceneObjectPart part in parts)
                 {
-                    foreach (SceneObjectPart part in m_parts.Values)
+                    if (part.Scale.X > 10.0 || part.Scale.Y > 10.0 || part.Scale.Z > 10.0)
                     {
                         if (part.Scale.X > m_scene.RegionInfo.PhysPrimMax || 
                             part.Scale.Y > m_scene.RegionInfo.PhysPrimMax ||
@@ -2704,12 +3007,13 @@ namespace OpenSim.Region.Framework.Scenes
                             break;
                         }
                     }
+                }
 
-                    foreach (SceneObjectPart part in m_parts.Values)
-                    {
-                        part.UpdatePrimFlags(UsePhysics, IsTemporary, IsPhantom, IsVolumeDetect);
-                    }
+                foreach (SceneObjectPart part in parts)
+                {
+                    part.UpdatePrimFlags(UsePhysics, IsTemporary, IsPhantom, IsVolumeDetect);
                 }
+                
             }
         }
 
@@ -2722,6 +3026,17 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
+
+
+        /// <summary>
+        /// Gets the number of parts
+        /// </summary>
+        /// <returns></returns>
+        public int GetPartCount()
+        {
+            return Children.Count;
+        }
+
         /// <summary>
         /// Get the parts of this scene object
         /// </summary>
@@ -2795,11 +3110,9 @@ namespace OpenSim.Region.Framework.Scenes
                 scale.Y = m_scene.m_maxNonphys;
             if (scale.Z > m_scene.m_maxNonphys)
                 scale.Z = m_scene.m_maxNonphys;
-
             SceneObjectPart part = GetChildPart(localID);
             if (part != null)
             {
-                part.Resize(scale);
                 if (part.PhysActor != null)
                 {
                     if (part.PhysActor.IsPhysical)
@@ -2814,7 +3127,7 @@ namespace OpenSim.Region.Framework.Scenes
                     part.PhysActor.Size = scale;
                     m_scene.PhysicsScene.AddPhysicsActorTaint(part.PhysActor);
                 }
-                //if (part.UUID != m_rootPart.UUID)
+                part.Resize(scale);
 
                 HasGroupChanged = true;
                 ScheduleGroupForFullUpdate();
@@ -2836,7 +3149,6 @@ namespace OpenSim.Region.Framework.Scenes
             SceneObjectPart part = GetChildPart(localID);
             if (part != null)
             {
-                part.IgnoreUndoUpdate = true;
                 if (scale.X > m_scene.m_maxNonphys)
                     scale.X = m_scene.m_maxNonphys;
                 if (scale.Y > m_scene.m_maxNonphys)
@@ -2856,94 +3168,100 @@ namespace OpenSim.Region.Framework.Scenes
                 float y = (scale.Y / part.Scale.Y);
                 float z = (scale.Z / part.Scale.Z);
 
-                lock (m_parts)
+                lockPartsForRead(true);
+                if (x > 1.0f || y > 1.0f || z > 1.0f)
                 {
-                    if (x > 1.0f || y > 1.0f || z > 1.0f)
+                    foreach (SceneObjectPart obPart in m_parts.Values)
                     {
-                        foreach (SceneObjectPart obPart in m_parts.Values)
+                        if (obPart.UUID != m_rootPart.UUID)
                         {
-                            if (obPart.UUID != m_rootPart.UUID)
-                            {
-                                obPart.IgnoreUndoUpdate = true;
-                                Vector3 oldSize = new Vector3(obPart.Scale);
+                            Vector3 oldSize = new Vector3(obPart.Scale);
+                            obPart.IgnoreUndoUpdate = true;
 
-                                float f = 1.0f;
-                                float a = 1.0f;
+                            float f = 1.0f;
+                            float a = 1.0f;
 
-                                if (part.PhysActor != null && part.PhysActor.IsPhysical)
+                            if (part.PhysActor != null && part.PhysActor.IsPhysical)
+                            {
+                                if (oldSize.X*x > m_scene.m_maxPhys)
                                 {
-                                    if (oldSize.X*x > m_scene.m_maxPhys)
-                                    {
-                                        f = m_scene.m_maxPhys / oldSize.X;
-                                        a = f / x;
-                                        x *= a;
-                                        y *= a;
-                                        z *= a;
-                                    }
-                                    if (oldSize.Y*y > m_scene.m_maxPhys)
-                                    {
-                                        f = m_scene.m_maxPhys / oldSize.Y;
-                                        a = f / y;
-                                        x *= a;
-                                        y *= a;
-                                        z *= a;
-                                    }
-                                    if (oldSize.Z*z > m_scene.m_maxPhys)
-                                    {
-                                        f = m_scene.m_maxPhys / oldSize.Z;
-                                        a = f / z;
-                                        x *= a;
-                                        y *= a;
-                                        z *= a;
-                                    }
+                                    f = m_scene.m_maxPhys / oldSize.X;
+                                    a = f / x;
+                                    x *= a;
+                                    y *= a;
+                                    z *= a;
                                 }
-                                else
+                                if (oldSize.Y*y > m_scene.m_maxPhys)
+                                {
+                                    f = m_scene.m_maxPhys / oldSize.Y;
+                                    a = f / y;
+                                    x *= a;
+                                    y *= a;
+                                    z *= a;
+                                }
+                                if (oldSize.Z*z > m_scene.m_maxPhys)
+                                {
+                                    f = m_scene.m_maxPhys / oldSize.Z;
+                                    a = f / z;
+                                    x *= a;
+                                    y *= a;
+                                    z *= a;
+                                }
+                            }
+                            else
+                            {
+                                if (oldSize.X*x > m_scene.m_maxNonphys)
+                                {
+                                    f = m_scene.m_maxNonphys / oldSize.X;
+                                    a = f / x;
+                                    x *= a;
+                                    y *= a;
+                                    z *= a;
+                                }
+                                if (oldSize.Y*y > m_scene.m_maxNonphys)
+                                {
+                                    f = m_scene.m_maxNonphys / oldSize.Y;
+                                    a = f / y;
+                                    x *= a;
+                                    y *= a;
+                                    z *= a;
+                                }
+                                if (oldSize.Z*z > m_scene.m_maxNonphys)
                                 {
-                                    if (oldSize.X*x > m_scene.m_maxNonphys)
-                                    {
-                                        f = m_scene.m_maxNonphys / oldSize.X;
-                                        a = f / x;
-                                        x *= a;
-                                        y *= a;
-                                        z *= a;
-                                    }
-                                    if (oldSize.Y*y > m_scene.m_maxNonphys)
-                                    {
-                                        f = m_scene.m_maxNonphys / oldSize.Y;
-                                        a = f / y;
-                                        x *= a;
-                                        y *= a;
-                                        z *= a;
-                                    }
-                                    if (oldSize.Z*z > m_scene.m_maxNonphys)
-                                    {
-                                        f = m_scene.m_maxNonphys / oldSize.Z;
-                                        a = f / z;
-                                        x *= a;
-                                        y *= a;
-                                        z *= a;
-                                    }
+                                    f = m_scene.m_maxNonphys / oldSize.Z;
+                                    a = f / z;
+                                    x *= a;
+                                    y *= a;
+                                    z *= a;
                                 }
-                                obPart.IgnoreUndoUpdate = false;
-                                obPart.StoreUndoState();
+                                
                             }
                         }
                     }
                 }
+                lockPartsForRead(false);
 
                 Vector3 prevScale = part.Scale;
                 prevScale.X *= x;
                 prevScale.Y *= y;
-                prevScale.Z *= z;
+                prevScale.Z *= z;;
+
+                part.IgnoreUndoUpdate = false;
+                part.StoreUndoState(UndoType.STATE_GROUP_SCALE);
+                part.IgnoreUndoUpdate = true;
                 part.Resize(prevScale);
+                part.IgnoreUndoUpdate = false;
 
-                lock (m_parts)
+                lockPartsForRead(true);
                 {
                     foreach (SceneObjectPart obPart in m_parts.Values)
                     {
-                        obPart.IgnoreUndoUpdate = true;
                         if (obPart.UUID != m_rootPart.UUID)
                         {
+                            obPart.IgnoreUndoUpdate = false;
+                            obPart.StoreUndoState(UndoType.STATE_GROUP_SCALE);
+                            obPart.IgnoreUndoUpdate = true;
+
                             Vector3 currentpos = new Vector3(obPart.OffsetPosition);
                             currentpos.X *= x;
                             currentpos.Y *= y;
@@ -2956,9 +3274,9 @@ namespace OpenSim.Region.Framework.Scenes
                             obPart.UpdateOffSet(currentpos);
                         }
                         obPart.IgnoreUndoUpdate = false;
-                        obPart.StoreUndoState();
                     }
                 }
+                lockPartsForRead(false);
 
                 if (part.PhysActor != null)
                 {
@@ -2967,7 +3285,6 @@ namespace OpenSim.Region.Framework.Scenes
                 }
 
                 part.IgnoreUndoUpdate = false;
-                part.StoreUndoState();
                 HasGroupChanged = true;
                 ScheduleGroupForTerseUpdate();
             }
@@ -2983,14 +3300,11 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="pos"></param>
         public void UpdateGroupPosition(Vector3 pos)
         {
-            foreach (SceneObjectPart part in Children.Values)
-            {
-                part.StoreUndoState();
-            }
             if (m_scene.EventManager.TriggerGroupMove(UUID, pos))
             {
                 if (IsAttachment)
                 {
+                    m_rootPart.StoreUndoState(UndoType.STATE_GROUP_POSITION);
                     m_rootPart.AttachedPos = pos;
                 }
                 if (RootPart.GetStatusSandbox())
@@ -3023,7 +3337,7 @@ namespace OpenSim.Region.Framework.Scenes
             SceneObjectPart part = GetChildPart(localID);
             foreach (SceneObjectPart parts in Children.Values)
             {
-                parts.StoreUndoState();
+                parts.StoreUndoState(UndoType.STATE_PRIM_POSITION);
             }
             if (part != null)
             {
@@ -3048,7 +3362,7 @@ namespace OpenSim.Region.Framework.Scenes
         {
             foreach (SceneObjectPart part in Children.Values)
             {
-                part.StoreUndoState();
+                part.StoreUndoState(UndoType.STATE_PRIM_POSITION);
             }
             Vector3 newPos = new Vector3(pos.X, pos.Y, pos.Z);
             Vector3 oldPos =
@@ -3061,7 +3375,7 @@ namespace OpenSim.Region.Framework.Scenes
             axDiff *= Quaternion.Inverse(partRotation);
             diff = axDiff;
 
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart obPart in m_parts.Values)
                 {
@@ -3071,11 +3385,29 @@ namespace OpenSim.Region.Framework.Scenes
                     }
                 }
             }
+            lockPartsForRead(false);
 
-            AbsolutePosition = newPos;
+            //We have to set undoing here because otherwise an undo state will be saved
+            if (!m_rootPart.Undoing)
+            {
+                m_rootPart.Undoing = true;
+                AbsolutePosition = newPos;
+                m_rootPart.Undoing = false;
+            }
+            else
+            {
+                AbsolutePosition = newPos;
+            }
 
             HasGroupChanged = true;
-            ScheduleGroupForTerseUpdate();
+            if (m_rootPart.Undoing)
+            {
+                ScheduleGroupForFullUpdate();
+            }
+            else
+            {
+                ScheduleGroupForTerseUpdate();
+            }
         }
 
         public void OffsetForNewRegion(Vector3 offset)
@@ -3095,7 +3427,7 @@ namespace OpenSim.Region.Framework.Scenes
         {
             foreach (SceneObjectPart parts in Children.Values)
             {
-                parts.StoreUndoState();
+                parts.StoreUndoState(UndoType.STATE_GROUP_ROTATION);
             }
             m_rootPart.UpdateRotation(rot);
 
@@ -3119,7 +3451,7 @@ namespace OpenSim.Region.Framework.Scenes
         {
             foreach (SceneObjectPart parts in Children.Values)
             {
-                parts.StoreUndoState();
+                parts.StoreUndoState(UndoType.STATE_GROUP_ROTATION);
             }
             m_rootPart.UpdateRotation(rot);
 
@@ -3146,7 +3478,7 @@ namespace OpenSim.Region.Framework.Scenes
             SceneObjectPart part = GetChildPart(localID);
             foreach (SceneObjectPart parts in Children.Values)
             {
-                parts.StoreUndoState();
+                parts.StoreUndoState(UndoType.STATE_PRIM_ROTATION);
             }
             if (part != null)
             {
@@ -3174,15 +3506,24 @@ namespace OpenSim.Region.Framework.Scenes
                 if (part.UUID == m_rootPart.UUID)
                 {
                     UpdateRootRotation(rot);
-                    AbsolutePosition = pos;
+                    if (!m_rootPart.Undoing)
+                    {
+                        m_rootPart.Undoing = true;
+                        AbsolutePosition = pos;
+                        m_rootPart.Undoing = false;
+                    }
+                    else
+                    {
+                        AbsolutePosition = pos;
+                    }
                 }
                 else
                 {
+                    part.StoreUndoState(UndoType.STATE_PRIM_ROTATION);
                     part.IgnoreUndoUpdate = true;
                     part.UpdateRotation(rot);
                     part.OffsetPosition = pos;
                     part.IgnoreUndoUpdate = false;
-                    part.StoreUndoState();
                 }
             }
         }
@@ -3196,7 +3537,13 @@ namespace OpenSim.Region.Framework.Scenes
             Quaternion axRot = rot;
             Quaternion oldParentRot = m_rootPart.RotationOffset;
 
-            m_rootPart.StoreUndoState();
+            m_rootPart.StoreUndoState(UndoType.STATE_PRIM_ROTATION);
+            bool cancelUndo = false;
+            if (!m_rootPart.Undoing)
+            {
+                m_rootPart.Undoing = true;
+                cancelUndo = true;
+            }
             m_rootPart.UpdateRotation(rot);
             if (m_rootPart.PhysActor != null)
             {
@@ -3204,33 +3551,31 @@ namespace OpenSim.Region.Framework.Scenes
                 m_scene.PhysicsScene.AddPhysicsActorTaint(m_rootPart.PhysActor);
             }
 
-            lock (m_parts)
+            lockPartsForRead(true);
+
+            foreach (SceneObjectPart prim in m_parts.Values)
             {
-                foreach (SceneObjectPart prim in m_parts.Values)
+                if (prim.UUID != m_rootPart.UUID)
                 {
-                    if (prim.UUID != m_rootPart.UUID)
-                    {
-                        prim.IgnoreUndoUpdate = true;
-                        Vector3 axPos = prim.OffsetPosition;
-                        axPos *= oldParentRot;
-                        axPos *= Quaternion.Inverse(axRot);
-                        prim.OffsetPosition = axPos;
-                        Quaternion primsRot = prim.RotationOffset;
-                        Quaternion newRot = primsRot * oldParentRot;
-                        newRot *= Quaternion.Inverse(axRot);
-                        prim.RotationOffset = newRot;
-                        prim.ScheduleTerseUpdate();
-                    }
+                    prim.IgnoreUndoUpdate = true;
+                    Vector3 axPos = prim.OffsetPosition;
+                    axPos *= oldParentRot;
+                    axPos *= Quaternion.Inverse(axRot);
+                    prim.OffsetPosition = axPos;
+                    Quaternion primsRot = prim.RotationOffset;
+                    Quaternion newRot = primsRot * oldParentRot;
+                    newRot *= Quaternion.Inverse(axRot);
+                    prim.RotationOffset = newRot;
+                    prim.ScheduleTerseUpdate();
+                    prim.IgnoreUndoUpdate = false;
                 }
             }
-            foreach (SceneObjectPart childpart in Children.Values)
+            if (cancelUndo == true)
             {
-                if (childpart != m_rootPart)
-                {
-                    childpart.IgnoreUndoUpdate = false;
-                    childpart.StoreUndoState();
-                }
+                m_rootPart.Undoing = false;
             }
+            lockPartsForRead(false);
+
             m_rootPart.ScheduleTerseUpdate();
         }
 
@@ -3352,7 +3697,7 @@ namespace OpenSim.Region.Framework.Scenes
                     if (atTargets.Count > 0)
                     {
                         uint[] localids = new uint[0];
-                        lock (m_parts)
+                        lockPartsForRead(true);
                         {
                             localids = new uint[m_parts.Count];
                             int cntr = 0;
@@ -3362,6 +3707,7 @@ namespace OpenSim.Region.Framework.Scenes
                                 cntr++;
                             }
                         }
+                        lockPartsForRead(false);
                         
                         for (int ctr = 0; ctr < localids.Length; ctr++)
                         {
@@ -3380,7 +3726,7 @@ namespace OpenSim.Region.Framework.Scenes
                     {
                         //trigger not_at_target
                         uint[] localids = new uint[0];
-                        lock (m_parts)
+                        lockPartsForRead(true);
                         {
                             localids = new uint[m_parts.Count];
                             int cntr = 0;
@@ -3390,7 +3736,8 @@ namespace OpenSim.Region.Framework.Scenes
                                 cntr++;
                             }
                         }
-                        
+                        lockPartsForRead(false);    
+
                         for (int ctr = 0; ctr < localids.Length; ctr++)
                         {
                             m_scene.EventManager.TriggerNotAtTargetEvent(localids[ctr]);
@@ -3431,7 +3778,8 @@ namespace OpenSim.Region.Framework.Scenes
                     if (atRotTargets.Count > 0)
                     {
                         uint[] localids = new uint[0];
-                        lock (m_parts)
+                        lockPartsForRead(true);
+                        try
                         {
                             localids = new uint[m_parts.Count];
                             int cntr = 0;
@@ -3441,6 +3789,10 @@ namespace OpenSim.Region.Framework.Scenes
                                 cntr++;
                             }
                         }
+                        finally
+                        {
+                            lockPartsForRead(false);
+                        }
 
                         for (int ctr = 0; ctr < localids.Length; ctr++)
                         {
@@ -3459,7 +3811,8 @@ namespace OpenSim.Region.Framework.Scenes
                     {
                         //trigger not_at_target
                         uint[] localids = new uint[0];
-                        lock (m_parts)
+                        lockPartsForRead(true);
+                        try
                         {
                             localids = new uint[m_parts.Count];
                             int cntr = 0;
@@ -3469,6 +3822,10 @@ namespace OpenSim.Region.Framework.Scenes
                                 cntr++;
                             }
                         }
+                        finally
+                        {
+                            lockPartsForRead(false);
+                        }
 
                         for (int ctr = 0; ctr < localids.Length; ctr++)
                         {
@@ -3482,19 +3839,20 @@ namespace OpenSim.Region.Framework.Scenes
         public float GetMass()
         {
             float retmass = 0f;
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
                     retmass += part.GetMass();
                 }
             }
+            lockPartsForRead(false);
             return retmass;
         }
         
         public void CheckSculptAndLoad()
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 if (!IsDeleted)
                 {
@@ -3519,6 +3877,7 @@ namespace OpenSim.Region.Framework.Scenes
                     }
                 }
             }
+            lockPartsForRead(false);
         }
 
         protected void AssetReceived(string id, Object sender, AssetBase asset)
@@ -3539,7 +3898,7 @@ namespace OpenSim.Region.Framework.Scenes
         /// <param name="client"></param>
         public void SetGroup(UUID GroupID, IClientAPI client)
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
@@ -3549,6 +3908,7 @@ namespace OpenSim.Region.Framework.Scenes
 
                 HasGroupChanged = true;
             }
+            lockPartsForRead(false);
 
             // Don't trigger the update here - otherwise some client issues occur when multiple updates are scheduled
             // for the same object with very different properties.  The caller must schedule the update.
@@ -3570,11 +3930,12 @@ namespace OpenSim.Region.Framework.Scenes
 
         public void SetAttachmentPoint(byte point)
         {
-            lock (m_parts)
+            lockPartsForRead(true);
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                     part.SetAttachmentPoint(point);
             }
+            lockPartsForRead(false);
         }
 
         #region ISceneObject
@@ -3608,6 +3969,14 @@ namespace OpenSim.Region.Framework.Scenes
             SetFromItemID(uuid);
         }
 
+        public void ResetOwnerChangeFlag()
+        {
+            ForEachPart(delegate(SceneObjectPart part)
+            {
+                part.ResetOwnerChangeFlag();
+            });
+        }
+
         #endregion
     }
 }