Merge branch 'danmerge_symsync' into dev

OpenSim/Region/Application/OpenSimBase.cs

@@ -411,6 +411,12 @@ namespace OpenSim
 
             scene.StartTimer();
 
+            //SYMMETRIC SYNC
+            //For INonSharedRegionModule, there is no more PostInitialise(). So we trigger OnPostSceneCreation event here
+            //to let the Sync modules to do their work once all modules are loaded and scene has interfaces to all of them.
+            scene.EventManager.TriggerOnPostSceneCreation(scene);
+            //end of SYMMETRIC SYNC
+
             return clientServer;
         }
 

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/RegionSyncServerModule.cs

@@ -75,7 +75,8 @@ namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
             }
 
             // If syncConfig does not indicate "server", do not start up server mode
-            string mode = syncConfig.GetString("Mode", "server").ToLower();
+            //string mode = syncConfig.GetString("Mode", "server").ToLower();
+            string mode = syncConfig.GetString("Mode", "").ToLower();
             if(mode != "server")
             {
                 scene.RegionSyncEnabled = false;

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/SymmetricSync/ClientManagerSyncModule.cs

@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) Contributors: TO BE FILLED
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using Nini.Config;
+using OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Framework.Client;
+using OpenSim.Region.CoreModules.Framework.InterfaceCommander;
+using OpenSim.Region.Framework.Interfaces;
+using OpenSim.Region.Framework.Scenes;
+using log4net;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using Mono.Addins;
+
+namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
+{
+
+    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "AttachmentsModule")]
+    public class ClientManagerSyncModule : INonSharedRegionModule, IDSGActorSyncModule
+    {
+        #region INonSharedRegionModule
+
+        public void Initialise(IConfigSource config)
+        {
+            m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+            IConfig syncConfig = config.Configs["RegionSyncModule"];
+            m_active = false;
+            if (syncConfig == null)
+            {
+                m_log.Warn(LogHeader + " No RegionSyncModule config section found. Shutting down.");
+                return;
+            }
+            else if (!syncConfig.GetBoolean("Enabled", false))
+            {
+                m_log.Warn(LogHeader + " RegionSyncModule is not enabled. Shutting down.");
+                return;
+            }
+
+            string actorType = syncConfig.GetString("DSGActorType", "").ToLower();
+
+            //Read in configuration, if the local actor is configured to be a client manager, load this module.
+            if (!actorType.Equals("client_manager"))
+            {
+                m_log.Warn(LogHeader + ": not configured as Scene Persistence Actor. Shut down.");
+                return;
+            }
+
+            m_actorID = syncConfig.GetString("ActorID", "");
+            if (m_actorID.Equals(""))
+            {
+                m_log.Warn(LogHeader + ": ActorID not specified in config file. Shutting down.");
+                return;
+            }
+
+            m_active = true;
+
+            m_log.Warn(LogHeader + " Initialised");
+
+        }
+
+        //Called after Initialise()
+        public void AddRegion(Scene scene)
+        {
+            if (!m_active)
+                return;
+
+            //connect with scene
+            m_scene = scene;
+
+            //register the module with SceneGraph. If needed, SceneGraph checks the module's ActorType to know what type of module it is.
+            m_scene.RegisterModuleInterface<IDSGActorSyncModule>(this);
+
+            // Setup the command line interface
+            //m_scene.EventManager.OnPluginConsole += EventManager_OnPluginConsole;
+            //InstallInterfaces();
+
+            //Register for the OnPostSceneCreation event
+            //m_scene.EventManager.OnPostSceneCreation += OnPostSceneCreation;
+
+            //Register for Scene/SceneGraph events
+            m_scene.SceneGraph.OnObjectCreate += new ObjectCreateDelegate(ClientManager_OnObjectCreate);
+            m_scene.EventManager.OnSymmetricSyncStop += ClientManager_OnSymmetricSyncStop;
+        }
+
+        //Called after AddRegion() has been called for all region modules of the scene.
+        //NOTE::However, at this point, Scene may not have requested all the needed region module interfaces yet.
+        public void RegionLoaded(Scene scene)
+        {
+            if (!m_active)
+                return;
+
+        }
+
+        public void RemoveRegion(Scene scene)
+        {
+        }
+
+        public Type ReplaceableInterface
+        {
+            get { return null; }
+        }
+
+        public void Close()
+        {
+            m_scene = null;
+        }
+
+        public string Name
+        {
+            get { return "ClientManagerSyncModule"; }
+        }
+
+        #endregion //INonSharedRegionModule
+
+
+        #region IDSGActorSyncModule members and functions
+
+        private DSGActorTypes m_actorType = DSGActorTypes.ClientManager;
+        public DSGActorTypes ActorType
+        {
+            get { return m_actorType; }
+        }
+
+        private string m_actorID;
+        public string ActorID
+        {
+            get { return m_actorID; }
+        }
+
+        #endregion //IDSGActorSyncModule
+
+        #region ClientManagerSyncModule memebers and functions
+        private ILog m_log;
+        private bool m_active = false;
+        public bool Active
+        {
+            get { return m_active; }
+        }
+
+        private Scene m_scene;
+
+        private string LogHeader = "[ClientManagerSyncModule]";
+
+        /// <summary>
+        /// Script Engine's action upon an object is added to the local scene
+        /// </summary>
+        private void ClientManager_OnObjectCreate(EntityBase entity)
+        {
+            if (entity is SceneObjectGroup)
+            {
+            }
+        }
+
+        public void ClientManager_OnSymmetricSyncStop()
+        {
+            //remove all objects
+            m_scene.DeleteAllSceneObjects();
+        }
+
+        #endregion //ScriptEngineSyncModule
+    }
+}

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/SymmetricSync/PhysicsEngineSyncModule.cs

@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) Contributors: TO BE FILLED
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using Nini.Config;
+using OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Framework.Client;
+using OpenSim.Region.CoreModules.Framework.InterfaceCommander;
+using OpenSim.Region.Framework.Interfaces;
+using OpenSim.Region.Framework.Scenes;
+using log4net;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using Mono.Addins;
+
+namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
+{
+
+    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "AttachmentsModule")]
+    public class PhysicsEngineSyncModule : INonSharedRegionModule, IDSGActorSyncModule
+    {
+        #region INonSharedRegionModule
+
+        public void Initialise(IConfigSource config)
+        {
+            m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+            IConfig syncConfig = config.Configs["RegionSyncModule"];
+            m_active = false;
+            if (syncConfig == null)
+            {
+                m_log.Warn(LogHeader + " No RegionSyncModule config section found. Shutting down.");
+                return;
+            }
+            else if (!syncConfig.GetBoolean("Enabled", false))
+            {
+                m_log.Warn(LogHeader + " RegionSyncModule is not enabled. Shutting down.");
+                return;
+            }
+
+            string actorType = syncConfig.GetString("DSGActorType", "").ToLower();
+
+            //Read in configuration, if the local actor is configured to be a client manager, load this module.
+            if (!actorType.Equals("physics_engine"))
+            {
+                m_log.Warn(LogHeader + ": not configured as Scene Persistence Actor. Shut down.");
+                return;
+            }
+
+            m_actorID = syncConfig.GetString("ActorID", "");
+            if (m_actorID.Equals(""))
+            {
+                m_log.Warn(LogHeader + ": ActorID not specified in config file. Shutting down.");
+                return;
+            }
+
+            m_active = true;
+
+            m_log.Warn(LogHeader + " Initialised");
+
+        }
+
+        //Called after Initialise()
+        public void AddRegion(Scene scene)
+        {
+            if (!m_active)
+                return;
+
+            //connect with scene
+            m_scene = scene;
+
+            //register the module with SceneGraph. If needed, SceneGraph checks the module's ActorType to know what type of module it is.
+            m_scene.RegisterModuleInterface<IDSGActorSyncModule>(this);
+
+            // Setup the command line interface
+            //m_scene.EventManager.OnPluginConsole += EventManager_OnPluginConsole;
+            //InstallInterfaces();
+
+            //Register for the OnPostSceneCreation event
+            //m_scene.EventManager.OnPostSceneCreation += OnPostSceneCreation;
+
+            //Register for Scene/SceneGraph events
+            m_scene.SceneGraph.OnObjectCreate += new ObjectCreateDelegate(PhysicsEngine_OnObjectCreate);
+            m_scene.EventManager.OnSymmetricSyncStop += PhysicsEngine_OnSymmetricSyncStop;
+        }
+
+        //Called after AddRegion() has been called for all region modules of the scene.
+        //NOTE::However, at this point, Scene may not have requested all the needed region module interfaces yet.
+        public void RegionLoaded(Scene scene)
+        {
+            if (!m_active)
+                return;
+
+        }
+
+        public void RemoveRegion(Scene scene)
+        {
+        }
+
+        public Type ReplaceableInterface
+        {
+            get { return null; }
+        }
+
+        public void Close()
+        {
+            m_scene = null;
+        }
+
+        public string Name
+        {
+            get { return "PhysicsEngineSyncModule"; }
+        }
+
+        #endregion //INonSharedRegionModule
+
+
+        #region IDSGActorSyncModule members and functions
+
+        private DSGActorTypes m_actorType = DSGActorTypes.PhysicsEngine;
+        public DSGActorTypes ActorType
+        {
+            get { return m_actorType; }
+        }
+
+        private string m_actorID;
+        public string ActorID
+        {
+            get { return m_actorID; }
+        }
+
+        #endregion //IDSGActorSyncModule
+
+        #region PhysicsEngineSyncModule memebers and functions
+        private ILog m_log;
+        private bool m_active = false;
+        public bool Active
+        {
+            get { return m_active; }
+        }
+
+        private Scene m_scene;
+
+        private string LogHeader = "[PhysicsEngineSyncModule]";
+
+        /// <summary>
+        /// Script Engine's action upon an object is added to the local scene
+        /// </summary>
+        private void PhysicsEngine_OnObjectCreate(EntityBase entity)
+        {
+            if (entity is SceneObjectGroup)
+            {
+            }
+        }
+
+        public void PhysicsEngine_OnSymmetricSyncStop()
+        {
+            //remove all objects
+            m_scene.DeleteAllSceneObjects();
+        }
+
+        #endregion //ScriptEngineSyncModule
+    }
+}

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/SymmetricSync/ScenePersistenceSyncModule.cs

@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) Contributors: TO BE FILLED
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using Nini.Config;
+using OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Framework.Client;
+using OpenSim.Region.CoreModules.Framework.InterfaceCommander;
+using OpenSim.Region.Framework.Interfaces;
+using OpenSim.Region.Framework.Scenes;
+using log4net;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using Mono.Addins;
+
+namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
+{
+    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "AttachmentsModule")]
+    public class ScenePersistenceSyncModule : INonSharedRegionModule, IDSGActorSyncModule    
+    {
+        #region INonSharedRegionModule
+
+        public void Initialise(IConfigSource config)
+        {
+            m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+            IConfig syncConfig = config.Configs["RegionSyncModule"];
+            m_active = false;
+            if (syncConfig == null)
+            {
+                m_log.Warn(LogHeader + " No RegionSyncModule config section found. Shutting down.");
+                return;
+            }
+            else if (!syncConfig.GetBoolean("Enabled", false))
+            {
+                m_log.Warn(LogHeader + " RegionSyncModule is not enabled. Shutting down.");
+                return;
+            }
+
+            string actorType = syncConfig.GetString("DSGActorType", "").ToLower();
+            if (!actorType.Equals("scene_persistence"))
+            {
+                m_log.Warn(LogHeader + ": not configured as Scene Persistence Actor. Shutting down.");
+                return;
+            }
+
+            m_actorID = syncConfig.GetString("ActorID", "");
+            if (m_actorID.Equals(""))
+            {
+                m_log.Warn(LogHeader + ": ActorID not specified in config file. Shutting down.");
+                return;
+            }
+
+            m_active = true;
+
+            m_log.Warn(LogHeader+" Initialised");
+
+        }
+
+        //Called after Initialise()
+        public void AddRegion(Scene scene)
+        {
+            if (!m_active)
+                return;
+            m_log.Warn(LogHeader + " AddRegion() called");
+            //connect with scene
+            m_scene = scene;
+
+            //register the module with SceneGraph. If needed, SceneGraph checks the module's ActorType to know what type of module it is.
+            m_scene.RegisterModuleInterface<IDSGActorSyncModule>(this);
+
+            // Setup the command line interface
+            //m_scene.EventManager.OnPluginConsole += EventManager_OnPluginConsole;
+            //InstallInterfaces();
+
+            //Register for the OnPostSceneCreation event
+            //m_scene.EventManager.OnPostSceneCreation += OnPostSceneCreation;
+
+            //Register for Scene/SceneGraph events
+            m_scene.SceneGraph.OnObjectCreate += new ObjectCreateDelegate(ScenePersistence_OnObjectCreate);
+        }
+
+        //Called after AddRegion() has been called for all region modules of the scene.
+        //NOTE::However, at this point, Scene may not have requested all the needed region module interfaces yet. 
+        //      So to try to access other region modules in RegionLoaded, e.g. RegionSyncModule, is not a good idea.
+        public void RegionLoaded(Scene scene)
+        {
+            if (!m_active)
+                return;
+            m_log.Warn(LogHeader + " RegionLoaded() called");
+
+        }
+
+        public void RemoveRegion(Scene scene)
+        {
+        }
+
+        public Type ReplaceableInterface
+        {
+            get { return null; }
+        }
+
+        public void Close()
+        {
+            m_scene = null;
+        }
+
+        public string Name
+        {
+            get { return "ScenePersistenceSyncModule"; }
+        }
+
+        #endregion //INonSharedRegionModule
+
+        #region IDSGActorSyncModule members and functions
+
+        private DSGActorTypes m_actorType = DSGActorTypes.ScenePersistence;
+        public DSGActorTypes ActorType
+        {
+            get { return m_actorType; }
+        }
+
+        private string m_actorID;
+        public string ActorID
+        {
+            get { return m_actorID; }
+        }
+
+        #endregion //IDSGActorSyncModule
+
+        #region ScenePersistenceSyncModule memebers and functions
+        private ILog m_log;
+        private bool m_active = false;
+        public bool Active
+        {
+            get { return m_active; }
+        }
+
+        private Scene m_scene;
+
+        private string LogHeader = "[ScenePersistenceSyncModule]";
+
+        public void OnPostSceneCreation(Scene createdScene)
+        {
+            //If this is the local scene the actor is working on, do something
+            if (createdScene == m_scene)
+            {
+            }
+        }
+
+        /// <summary>
+        /// ScenePersistence's actions upon an object is added to the local scene.
+        /// </summary>
+        private void ScenePersistence_OnObjectCreate(EntityBase entity)
+        {
+            if (entity is SceneObjectGroup)
+            {
+                m_log.Warn(LogHeader + ": link to backup for " + entity.UUID);
+                SceneObjectGroup sog = (SceneObjectGroup)entity;
+                sog.AttachToBackup();
+            }
+        }
+
+        #endregion //ScenePersistenceSyncModule
+    }
+
+
+
+}

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/SymmetricSync/ScriptEngineSyncModule.cs

@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) Contributors: TO BE FILLED
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using Nini.Config;
+using OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Framework.Client;
+using OpenSim.Region.CoreModules.Framework.InterfaceCommander;
+using OpenSim.Region.Framework.Interfaces;
+using OpenSim.Region.Framework.Scenes;
+using log4net;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using Mono.Addins;
+
+namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
+{
+    
+    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "AttachmentsModule")]
+    public class ScriptEngineSyncModule : INonSharedRegionModule, IDSGActorSyncModule
+    {
+        #region INonSharedRegionModule
+
+        public void Initialise(IConfigSource config)
+        {
+            m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+            IConfig syncConfig = config.Configs["RegionSyncModule"];
+            m_active = false;
+            if (syncConfig == null)
+            {
+                m_log.Warn(LogHeader + " No RegionSyncModule config section found. Shutting down.");
+                return;
+            }
+            else if (!syncConfig.GetBoolean("Enabled", false))
+            {
+                m_log.Warn(LogHeader + " RegionSyncModule is not enabled. Shutting down.");
+                return;
+            }
+
+            string actorType = syncConfig.GetString("DSGActorType", "").ToLower();
+            if (!actorType.Equals("script_engine"))
+            {
+                m_log.Warn(LogHeader + ": not configured as Scene Persistence Actor. Shut down.");
+                return;
+            }
+
+            m_actorID = syncConfig.GetString("ActorID", "");
+            if (m_actorID.Equals(""))
+            {
+                m_log.Warn(LogHeader + ": ActorID not specified in config file. Shutting down.");
+                return;
+            }
+
+            m_active = true;
+
+            m_log.Warn(LogHeader + " Initialised");
+
+        }
+
+        //Called after Initialise()
+        public void AddRegion(Scene scene)
+        {
+            if (!m_active)
+                return;
+            m_log.Warn(LogHeader + " AddRegion() called");
+            //connect with scene
+            m_scene = scene;
+
+            //register the module with SceneGraph. If needed, SceneGraph checks the module's ActorType to know what type of module it is.
+            m_scene.RegisterModuleInterface<IDSGActorSyncModule>(this);
+
+            // Setup the command line interface
+            //m_scene.EventManager.OnPluginConsole += EventManager_OnPluginConsole;
+            //InstallInterfaces();
+
+            //Register for the OnPostSceneCreation event
+            //m_scene.EventManager.OnPostSceneCreation += OnPostSceneCreation;
+
+            //Register for Scene/SceneGraph events
+            m_scene.SceneGraph.OnObjectCreate += new ObjectCreateDelegate(ScriptEngine_OnObjectCreate);
+            m_scene.EventManager.OnSymmetricSyncStop += ScriptEngine_OnSymmetricSyncStop;
+        }
+
+        //Called after AddRegion() has been called for all region modules of the scene.
+        //NOTE::However, at this point, Scene may not have requested all the needed region module interfaces yet.
+        public void RegionLoaded(Scene scene)
+        {
+            if (!m_active)
+                return;
+
+        }
+
+        public void RemoveRegion(Scene scene)
+        {
+        }
+
+        public Type ReplaceableInterface
+        {
+            get { return null; }
+        }
+
+        public void Close()
+        {
+            m_scene = null;
+        }
+
+        public string Name
+        {
+            get { return "ScriptEngineSyncModule"; }
+        }
+
+        #endregion //INonSharedRegionModule
+
+        #region IDSGActorSyncModule members and functions
+
+        private DSGActorTypes m_actorType = DSGActorTypes.ScriptEngine;
+        public DSGActorTypes ActorType
+        {
+            get { return m_actorType; }
+        }
+
+        private string m_actorID;
+        public string ActorID
+        {
+            get { return m_actorID; }
+        }
+
+        #endregion //IDSGActorSyncModule
+
+
+        #region ScriptEngineSyncModule memebers and functions
+        private ILog m_log;
+        private bool m_active = false;
+        public bool Active
+        {
+            get { return m_active; }
+        }
+
+        private Scene m_scene;
+
+        private string LogHeader = "[ScriptEngineSyncModule]";
+
+        public void OnPostSceneCreation(Scene createdScene)
+        {
+            //If this is the local scene the actor is working on, do something
+            if (createdScene == m_scene)
+            {
+            }
+        }
+
+        /// <summary>
+        /// Script Engine's action upon an object is added to the local scene
+        /// </summary>
+        private void ScriptEngine_OnObjectCreate(EntityBase entity)
+        {
+            if (entity is SceneObjectGroup)
+            {
+                m_log.Warn(LogHeader + ": start script for obj " + entity.UUID);
+                SceneObjectGroup sog = (SceneObjectGroup)entity; 
+                sog.CreateScriptInstances(0, false, m_scene.DefaultScriptEngine, 0);
+                sog.ResumeScripts();
+            }
+        }
+
+        public void ScriptEngine_OnSymmetricSyncStop()
+        {
+            //Inform script engine to save script states and stop scripts
+            m_scene.EventManager.TriggerScriptEngineSyncStop();
+            //remove all objects
+            m_scene.DeleteAllSceneObjects();
+        }
+
+        #endregion //ScriptEngineSyncModule
+
+    }
+     
+
+}

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/SymmetricSync/SymmetricSyncMessage.cs

@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) Contributors: TO BE FILLED
+ */
+
+using System;
+using System.IO;
+using OpenMetaverse;
+using log4net;
+
+namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
+{
+    //Initial code in SymmetricSyncMessage copied from RegionSyncMessage. 
+
+    /// <summary>
+    /// Types of symmetric sync messages among actors. 
+    /// NOTE:: To enable message subscription, we may need to move the definition of MsgType to, say IRegionSyncModule, so that it can be exposed to other region modules.
+    /// </summary>
+    public class SymmetricSyncMessage
+    {
+        #region MsgType Enum
+        public enum MsgType
+        {
+            Null,
+            // Actor -> SIM(Scene)
+            GetTerrain,
+            GetObjects,
+            
+            // SIM -> CM
+            Terrain,
+            NewObject,       // objects
+            UpdatedObject,   // objects
+            RemovedObject,   // objects
+            // BIDIR
+            //EchoRequest,
+            //EchoResponse,
+            RegionName,
+            //RegionStatus,
+            ActorID,
+        }
+        #endregion
+
+        #region Member Data
+        private MsgType m_type;
+        private byte[] m_data;
+        static ILog m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+        #endregion
+
+        #region Constructors
+        public SymmetricSyncMessage(MsgType type, byte[] data)
+        {
+            m_type = type;
+            m_data = data;
+        }
+
+        public SymmetricSyncMessage(MsgType type, string msg)
+        {
+            m_type = type;
+            m_data = System.Text.Encoding.ASCII.GetBytes(msg);
+        }
+
+        public SymmetricSyncMessage(MsgType type)
+        {
+            m_type = type;
+            m_data = new byte[0];
+        }
+
+        public SymmetricSyncMessage(Stream stream)
+        {
+            //ILog log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+            //try
+            {
+                m_type = (MsgType)Utils.BytesToInt(GetBytesFromStream(stream, 4));
+                int length = Utils.BytesToInt(GetBytesFromStream(stream, 4));
+                m_data = GetBytesFromStream(stream, length);
+                //log.WarnFormat("RegionSyncMessage Constructed {0} ({1} bytes)", m_type.ToString(), length);
+            }
+        }
+
+        private byte[] GetBytesFromStream(Stream stream, int count)
+        {
+            // Loop to receive the message length
+            byte[] ret = new byte[count];
+            int i = 0;
+            while (i < count)
+            {
+                i += stream.Read(ret, i, count - i);
+            }
+            return ret;
+        }
+
+        #endregion
+
+        #region Accessors
+        public MsgType Type
+        {
+            get { return m_type; }
+        }
+
+        public int Length
+        {
+            get { return m_data.Length; }
+        }
+
+        public byte[] Data
+        {
+            get { return m_data; }
+        }
+        #endregion
+
+        #region Conversions
+        public byte[] ToBytes()
+        {
+            byte[] buf = new byte[m_data.Length + 8];
+            Utils.IntToBytes((int)m_type, buf, 0);
+            Utils.IntToBytes(m_data.Length, buf, 4);
+            Array.Copy(m_data, 0, buf, 8, m_data.Length);
+            return buf;
+        }
+
+        public override string ToString()
+        {
+            return String.Format("{0} ({1} bytes)", m_type.ToString(), m_data.Length.ToString());
+        }
+        #endregion
+
+
+        public static void HandleSuccess(string header, SymmetricSyncMessage msg, string message)
+        {
+            m_log.WarnFormat("{0} Handled {1}: {2}", header, msg.ToString(), message);
+        }
+
+        public static void HandleTrivial(string header, SymmetricSyncMessage msg, string message)
+        {
+            m_log.WarnFormat("{0} Issue handling {1}: {2}", header, msg.ToString(), message);
+        }
+
+        public static void HandleWarning(string header, SymmetricSyncMessage msg, string message)
+        {
+            m_log.WarnFormat("{0} Warning handling {1}: {2}", header, msg.ToString(), message);
+        }
+
+        public static void HandleError(string header, SymmetricSyncMessage msg, string message)
+        {
+            m_log.WarnFormat("{0} Error handling {1}: {2}", header, msg.ToString(), message);
+        }
+
+        public static bool HandlerDebug(string header, SymmetricSyncMessage msg, string message)
+        {
+            m_log.WarnFormat("{0} DBG ({1}): {2}", header, msg.ToString(), message);
+            return true;
+        }
+    }
+}

OpenSim/Region/CoreModules/RegionSync/RegionSyncModule/SymmetricSync/SyncConnector.cs

@@ -0,0 +1,298 @@
+/*
+ * Copyright (c) Contributors: TO BE FILLED
+ */
+
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Net.Sockets;
+using System.Threading;
+using System.Text;
+using log4net;
+using OpenMetaverse;
+
+namespace OpenSim.Region.CoreModules.RegionSync.RegionSyncModule
+{
+    // For implementations, a lot was copied from RegionSyncClientView, especially the SendLoop/ReceiveLoop.
+    public class SyncConnector
+    {
+        private TcpClient m_tcpConnection = null;
+        private RegionSyncListenerInfo m_remoteListenerInfo = null;
+        private Thread m_rcvLoop;
+        private Thread m_send_loop;
+
+        private string LogHeader = "[SYNC CONNECTOR]";
+        // The logfile
+        private ILog m_log;
+
+        //members for in/out messages queueing
+        object stats = new object();
+        private long queuedUpdates=0;
+        private long dequeuedUpdates=0;
+        private long msgsIn=0;
+        private long msgsOut=0;
+        private long bytesIn=0;
+        private long bytesOut=0;
+        private int msgCount = 0;
+        // A queue for outgoing traffic. 
+        private BlockingUpdateQueue m_outQ = new BlockingUpdateQueue();
+
+        private RegionSyncModule m_regionSyncModule = null;
+
+        private int m_connectorNum;
+        public int ConnectorNum
+        {
+            get { return m_connectorNum; }
+        }
+
+        //the actorID of the other end of the connection
+        private string m_syncOtherSideActorID;
+        public string OtherSideActorID
+        {
+            get { return m_syncOtherSideActorID; }
+            set { m_syncOtherSideActorID = value; }
+        }
+
+        //The region name of the other side of the connection
+        private string m_syncOtherSideRegionName="";
+        public string OtherSideRegionName
+        {
+            get { return m_syncOtherSideRegionName; }
+        }
+
+        // Check if the client is connected
+        public bool Connected
+        { get { return (m_tcpConnection !=null && m_tcpConnection.Connected); } }
+
+        public string Description
+        {
+            get
+            {
+                if (m_syncOtherSideRegionName == null)
+                    return String.Format("SyncConnector #{0}", m_connectorNum);
+                return String.Format("SyncConnector #{0} ({1:10})", m_connectorNum, m_syncOtherSideRegionName);
+            }
+        }
+
+        /// <summary>
+        /// The constructor that will be called when a SyncConnector is created passively: a remote SyncConnector has initiated the connection.
+        /// </summary>
+        /// <param name="connectorNum"></param>
+        /// <param name="tcpclient"></param>
+        public SyncConnector(int connectorNum, TcpClient tcpclient, RegionSyncModule syncModule)
+        {
+            m_tcpConnection = tcpclient;
+            m_connectorNum = connectorNum;
+            m_regionSyncModule = syncModule;
+            m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+        }
+
+        /// <summary>
+        /// The constructor that will be called when a SyncConnector is created actively: it is created to send connection request to a remote listener
+        /// </summary>
+        /// <param name="connectorNum"></param>
+        /// <param name="listenerInfo"></param>
+        public SyncConnector(int connectorNum, RegionSyncListenerInfo listenerInfo, RegionSyncModule syncModule)
+        {
+            m_remoteListenerInfo = listenerInfo;
+            m_connectorNum = connectorNum;
+            m_regionSyncModule = syncModule;
+            m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+        }
+
+        //Connect to the remote listener
+        public bool Connect()
+        {
+            m_tcpConnection = new TcpClient();
+            try
+            {
+                m_tcpConnection.Connect(m_remoteListenerInfo.Addr, m_remoteListenerInfo.Port);
+            }
+            catch (Exception e)
+            {
+                m_log.WarnFormat("{0} [Start] Could not connect to RegionSyncServer at {1}:{2}", LogHeader, m_remoteListenerInfo.Addr, m_remoteListenerInfo.Port);
+                m_log.Warn(e.Message);
+                return false;
+            }
+            return true;
+        }
+
+        /// <summary>
+        /// Start both the send and receive threads
+        /// </summary>
+        public void StartCommThreads()
+        {
+            // Create a thread for the receive loop
+            m_rcvLoop = new Thread(new ThreadStart(ReceiveLoop));
+            m_rcvLoop.Name = Description + " (ReceiveLoop)";
+            m_log.WarnFormat("{0} Starting {1} thread", Description, m_rcvLoop.Name);
+            m_rcvLoop.Start();
+
+            // Create a thread for the send loop
+            m_send_loop = new Thread(new ThreadStart(delegate() { SendLoop(); }));
+            m_send_loop.Name = Description + " (SendLoop)";
+            m_log.WarnFormat("{0} Starting {1} thread", Description, m_send_loop.Name);
+            m_send_loop.Start();
+        }
+
+        public void Shutdown()
+        {
+            m_log.Warn(LogHeader + " shutdown connection");
+            // Abort receive and send loop
+            m_rcvLoop.Abort();
+            m_send_loop.Abort();
+
+            // Close the connection
+            m_tcpConnection.Client.Close();
+            m_tcpConnection.Close();
+        }
+
+        ///////////////////////////////////////////////////////////
+        // Sending messages out to the other side of the connection
+        ///////////////////////////////////////////////////////////
+        // Send messages from the update Q as fast as we can DeQueue them
+        // *** This is the main send loop thread for each connected client
+        private void SendLoop()
+        {
+            try
+            {
+                while (true)
+                {
+                    // Dequeue is thread safe
+                    byte[] update = m_outQ.Dequeue();
+                    lock (stats)
+                        dequeuedUpdates++;
+                    Send(update);
+                }
+            }
+            catch (Exception e)
+            {
+                m_log.ErrorFormat("{0} has disconnected: {1} (SendLoop)", Description, e.Message);
+            }
+            Shutdown();
+        }
+
+        /// <summary>
+        /// Enqueue update of an object/avatar into the outgoing queue, and return right away
+        /// </summary>
+        /// <param name="id">UUID of the object/avatar</param>
+        /// <param name="update">the update infomation in byte format</param>
+        public void EnqueueOutgoingUpdate(UUID id, byte[] update)
+        {
+            lock (stats)
+                queuedUpdates++;
+            // Enqueue is thread safe
+            m_outQ.Enqueue(id, update);
+        }
+
+        //Send out a messge directly. This should only by called for short messages that are not sent frequently.
+        //Don't call this function for sending out updates. Call EnqueueOutgoingUpdate instead
+        public void Send(SymmetricSyncMessage msg)
+        {
+            Send(msg.ToBytes());
+        }
+
+        private void Send(byte[] data)
+        {
+            if (m_tcpConnection.Connected)
+            {
+                try
+                {
+                    lock (stats)
+                    {
+                        msgsOut++;
+                        bytesOut += data.Length;
+                    }
+                    m_tcpConnection.GetStream().BeginWrite(data, 0, data.Length, ar =>
+                    {
+                        if (m_tcpConnection.Connected)
+                        {
+                            try
+                            {
+                                m_tcpConnection.GetStream().EndWrite(ar);
+                            }
+                            catch (Exception)
+                            { }
+                        }
+                    }, null);
+                }
+                catch (IOException)
+                {
+                    m_log.WarnFormat("{0}:{1} has disconnected.", Description, m_connectorNum);
+                }
+            }
+        }
+
+        ///////////////////////////////////////////////////////////
+        // Receiving messages from the other side ofthe connection
+        ///////////////////////////////////////////////////////////
+        private void ReceiveLoop()
+        {
+            m_log.WarnFormat("{0} Thread running: {1}", LogHeader, m_rcvLoop.Name);
+            while (true && m_tcpConnection.Connected)
+            {
+                SymmetricSyncMessage msg;
+                // Try to get the message from the network stream
+                try
+                {
+                    msg = new SymmetricSyncMessage(m_tcpConnection.GetStream());
+                    //m_log.WarnFormat("{0} Received: {1}", LogHeader, msg.ToString());
+                }
+                // If there is a problem reading from the client, shut 'er down. 
+                catch
+                {
+                    //ShutdownClient();
+                    m_log.WarnFormat("{0}:{1} has disconnected.", Description, m_connectorNum);
+                    Shutdown();
+                    return;
+                }
+                // Try handling the message
+                try
+                {
+                    HandleMessage(msg);
+                }
+                catch (Exception e)
+                {
+                    m_log.WarnFormat("{0} Encountered an exception: {1} (MSGTYPE = {2})", Description, e.Message, msg.ToString());
+                }
+            }
+        }
+
+        private void HandleMessage(SymmetricSyncMessage msg)
+        {
+
+            msgCount++;
+            switch (msg.Type)
+            {
+                case SymmetricSyncMessage.MsgType.RegionName:
+                    {
+                        m_syncOtherSideRegionName = Encoding.ASCII.GetString(msg.Data, 0, msg.Length);
+                        if (m_regionSyncModule.IsSyncRelay)
+                        {
+                            SymmetricSyncMessage outMsg = new SymmetricSyncMessage(SymmetricSyncMessage.MsgType.RegionName, m_regionSyncModule.LocalScene.RegionInfo.RegionName);
+                            Send(outMsg);
+                        }
+                        m_log.DebugFormat("Syncing to region \"{0}\"", m_syncOtherSideRegionName); 
+                        return;
+                    }
+                case SymmetricSyncMessage.MsgType.ActorID:
+                    {
+                        m_syncOtherSideActorID = Encoding.ASCII.GetString(msg.Data, 0, msg.Length);
+                        if (m_regionSyncModule.IsSyncRelay)
+                        {
+                            SymmetricSyncMessage outMsg = new SymmetricSyncMessage(SymmetricSyncMessage.MsgType.ActorID, m_regionSyncModule.ActorID);
+                            Send(outMsg);
+                        }
+                        m_log.DebugFormat("Syncing to actor \"{0}\"", m_syncOtherSideActorID);
+                        return;
+                    }
+                default:
+                    break;
+            }
+
+            //For any other messages, we simply deliver the message to RegionSyncModule for now.
+            //Later on, we may deliver messages to different modules, say sync message to RegionSyncModule and event message to ActorSyncModule.
+            m_regionSyncModule.HandleIncomingMessage(msg);
+        }
+    }
+}

OpenSim/Region/CoreModules/World/Terrain/TerrainModule.cs

@@ -589,6 +589,56 @@ namespace OpenSim.Region.CoreModules.World.Terrain
             client.OnUnackedTerrain += client_OnUnackedTerrain;
         }
         
+        //SYMMETRIC SYNC
+        private long m_lastUpdateTimeStamp = DateTime.Now.Ticks;
+        public long LastUpdateTimeStamp
+        {
+            get { return m_lastUpdateTimeStamp; }
+            set { m_lastUpdateTimeStamp = value; }
+        }
+
+        private string m_lastUpdateActorID;
+        public string LastUpdateActorID
+        {
+            get { return m_lastUpdateActorID; }
+            set { m_lastUpdateActorID = value; }
+        }
+
+        private void SyncInfoUpdate(long timeStamp, string actorID)
+        {
+            m_lastUpdateTimeStamp = timeStamp;
+            m_lastUpdateActorID = actorID;
+        }
+
+        /*
+        public void CheckForTerrainUpdatesBySynchronization(long timeStamp, string actorID)
+        {
+            SyncInfoUpdate(timeStamp, actorID);
+            CheckForTerrainUpdates(false);
+        }
+         * */
+
+        public void TaintTerrianBySynchronization(long timeStamp, string actorID)
+        {
+            SyncInfoUpdate(timeStamp, actorID);
+            CheckForTerrainUpdates(false, timeStamp, actorID);
+        }
+
+        public bool TerrianModifiedLocally(string localActorID)
+        {
+            if (localActorID == m_lastUpdateActorID)
+                return true;
+            return false;
+        }
+
+        public void GetSyncInfo(out long lastUpdateTimeStamp, out string lastUpdateActorID)
+        {
+            lastUpdateTimeStamp = m_lastUpdateTimeStamp;
+            lastUpdateActorID = m_lastUpdateActorID;
+        }
+
+        //end of SYMMETRIC SYNC
+
         /// <summary>
         /// Checks to see if the terrain has been modified since last check
         /// but won't attempt to limit those changes to the limits specified in the estate settings
@@ -596,7 +646,21 @@ namespace OpenSim.Region.CoreModules.World.Terrain
         /// </summary>
         private void CheckForTerrainUpdates()
         {
-            CheckForTerrainUpdates(false);
+            //SYMMETRIC SYNC
+
+            //Assumption: Thus function is only called when the terrain is updated by the local actor. 
+            //            Updating terrain during receiving sync messages from another actor will call CheckForTerrainUpdates.
+
+            //Update the timestamp to the current time tick, and set the LastUpdateActorID to be self
+            long currentTimeTick = DateTime.Now.Ticks;
+            string localActorID = m_scene.GetSyncActorID();
+            SyncInfoUpdate(currentTimeTick, localActorID);
+            //Check if the terrain has been modified and send out sync message if modified.
+            CheckForTerrainUpdates(false, currentTimeTick, localActorID);
+
+            //end of SYMMETRIC SYNC
+
+            //CheckForTerrainUpdates(false);
         }
 
         /// <summary>
@@ -607,7 +671,10 @@ namespace OpenSim.Region.CoreModules.World.Terrain
         /// currently invoked by client_OnModifyTerrain only and not the Commander interfaces
         /// <param name="respectEstateSettings">should height map deltas be limited to the estate settings limits</param>
         /// </summary>
-        private void CheckForTerrainUpdates(bool respectEstateSettings)
+        //private void CheckForTerrainUpdates(bool respectEstateSettings)
+        //SYMMETRIC SYNC: Change the interface, to input the right sync information for the most recent update
+        private void CheckForTerrainUpdates(bool respectEstateSettings, long lastUpdateTimeStamp, string lastUpdateActorID)
+        //end of SYMMETRIC SYNC
         {
             bool shouldTaint = false;
             float[] serialised = m_channel.GetFloatsSerialised();
@@ -636,6 +703,13 @@ namespace OpenSim.Region.CoreModules.World.Terrain
             if (shouldTaint)
             {
                 m_tainted = true;
+                //SYMMETRIC SYNC
+                //Terrain has been modified, send out sync message if needed
+                if (m_scene.RegionSyncModule != null)
+                {
+                    m_scene.RegionSyncModule.SendTerrainUpdates(m_lastUpdateActorID);
+                }
+                //end of SYMMETRIC SYNC
             }
         }
 
@@ -748,7 +822,10 @@ namespace OpenSim.Region.CoreModules.World.Terrain
                         m_painteffects[(StandardTerrainEffects) action].PaintEffect(
                             m_channel, allowMask, west, south, height, size, seconds);
 
-                        CheckForTerrainUpdates(!god); //revert changes outside estate limits
+                        //CheckForTerrainUpdates(!god); //revert changes outside estate limits
+                        //SYMMETRIC SYNC
+                        CheckForTerrainUpdates(!god, DateTime.Now.Ticks, m_scene.GetSyncActorID());
+                        //end of SYMMETRIC SYNC
                     }
                 }
                 else
@@ -789,7 +866,10 @@ namespace OpenSim.Region.CoreModules.World.Terrain
                         m_floodeffects[(StandardTerrainEffects) action].FloodEffect(
                             m_channel, fillArea, size);
 
-                        CheckForTerrainUpdates(!god); //revert changes outside estate limits
+                        //CheckForTerrainUpdates(!god); //revert changes outside estate limits
+                        //SYMMETRIC SYNC
+                        CheckForTerrainUpdates(!god, DateTime.Now.Ticks, m_scene.GetSyncActorID());
+                        //end of SYMMETRIC SYNC
                     }
                 }
                 else

OpenSim/Region/Framework/Interfaces/ITerrainModule.cs

@@ -64,5 +64,21 @@ namespace OpenSim.Region.Framework.Interfaces
         void InstallPlugin(string name, ITerrainEffect plug);
 
         void UndoTerrain(ITerrainChannel channel);
+
+        //SYMMETRIC SYNC
+        void TaintTerrianBySynchronization(long timeStamp, string actorID);
+        /// <summary>
+        /// Return true if the most recent update on terrain is done locally (i.e. not by receiving a terrain-sync message).
+        /// </summary>
+        /// <param name="localActorID"></param>
+        /// <returns></returns>
+        bool TerrianModifiedLocally(string localActorID);
+        /// <summary>
+        /// Obtain the timestemp and actorID information for the most recent update on terrain.
+        /// </summary>
+        /// <param name="lastUpdateTimeStamp"></param>
+        /// <param name="lastUpdateActorID"></param>
+        void GetSyncInfo(out long lastUpdateTimeStamp, out string lastUpdateActorID);
+        //end of SYMMETRIC SYNC
     }
 }

OpenSim/Region/Framework/Scenes/EventManager.cs

@@ -376,7 +376,6 @@ namespace OpenSim.Region.Framework.Scenes
         public delegate void RegionUp(GridRegion region);
         public event RegionUp OnRegionUp;
 
-
         public class MoneyTransferArgs : EventArgs
         {
             public UUID sender;
@@ -2184,7 +2183,7 @@ namespace OpenSim.Region.Framework.Scenes
                     catch (Exception e)
                     {
                         m_log.ErrorFormat(
-                            "[EVENT MANAGER]: Delegate for TriggerOnSceneObjectLoaded failed - continuing.  {0} {1}", 
+                            "[EVENT MANAGER]: Delegate for TriggerScriptEngineSyncStop failed - continuing.  {0} {1}", 
                             e.Message, e.StackTrace);
                     }
                 }
@@ -2243,5 +2242,55 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
         #endregion
+
+        //SYMMETRIC SYNC
+        public event PostSceneCreation OnPostSceneCreation;
+        public delegate void PostSceneCreation(Scene createdScene);
+
+        public void TriggerOnPostSceneCreation(Scene createdScene)
+        {
+            PostSceneCreation handler = OnPostSceneCreation;
+            if (handler != null)
+            {
+                foreach (PostSceneCreation d in handler.GetInvocationList())
+                {
+                    try
+                    {
+                        d(createdScene);
+                    }
+                    catch (Exception e)
+                    {
+                        m_log.ErrorFormat(
+                            "[EVENT MANAGER]: Delegate for TriggerOnPostSceneCreation failed - continuing.  {0} {1}",
+                            e.Message, e.StackTrace);
+                    }
+                }
+            }
+        }
+
+        public delegate void SymmetricSyncStop();
+        public event SymmetricSyncStop OnSymmetricSyncStop;
+        public void TriggerOnSymmetricSyncStop()
+        {
+            SymmetricSyncStop handlerSymmetricSyncStop = OnSymmetricSyncStop;
+            if (handlerSymmetricSyncStop != null)
+            {
+                foreach (SymmetricSyncStop d in handlerSymmetricSyncStop.GetInvocationList())
+                {
+                    try
+                    {
+                        d();
+                    }
+                    catch (Exception e)
+                    {
+                        m_log.ErrorFormat(
+                            "[EVENT MANAGER]: Delegate for TriggerOnSymmetricSyncStop failed - continuing.  {0} {1}",
+                            e.Message, e.StackTrace);
+                    }
+                }
+            }
+        }
+
+        //end of SYMMETRIC SYNC
     }
 }

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -408,7 +408,10 @@ namespace OpenSim.Region.Framework.Scenes
         {
             get { return m_AvatarFactory; }
         }
-        #region REGION SYNC
+
+
+        #region REGION SYNC -- Asymmetric sync, old style, depreciated ---------
+
         protected IRegionSyncServerModule m_regionSyncServerModule;
         protected IRegionSyncClientModule m_regionSyncClientModule;
 
@@ -576,6 +579,100 @@ namespace OpenSim.Region.Framework.Scenes
         // }
 
         #endregion 
+
+
+        #region SYMMETRIC SYNC
+        ///////////////////////////////////////////////////////////////////////////////////////////////
+        //KittyL: 12/23/2010. SYMMETRIC SYNC: Implementation for the symmetric synchronization model.
+        ///////////////////////////////////////////////////////////////////////////////////////////////
+
+        private IRegionSyncModule m_regionSyncModule = null;
+        public IRegionSyncModule RegionSyncModule
+        {
+            get { return m_regionSyncModule; }
+            //set { m_regionSyncModule = value; }
+        }
+
+        private IDSGActorSyncModule m_DSGActorSyncModule = null;
+        public IDSGActorSyncModule ActorSyncModule
+        {
+            get { return m_DSGActorSyncModule; }
+
+        }
+
+        //This enumeration would help to identify if after a NewObject/UpdatedObject message is received,
+        //the object is a new object and hence added to the scene graph, or it an object with some properties
+        //just updated, or the copy of the object in the UpdatedObject message is the same with local copy 
+        //(before we add time-stamp to identify updates from different actors/scene, it could be possible the same
+        //update be forwarded, say from script engine to scene, and then back to script engine.
+        public enum ObjectUpdateResult
+        {
+            New, //the New/UpdatedObject message ends up adding a new object to local scene graph
+            Updated, //the object has some property updated after processing the New/UpdatedObject 
+            Unchanged, //no property of the object has been changed after processing the New/UpdatedObject 
+            //(it probably is the same update this end has sent out before
+            Error //Errors happen during processing the message, e.g. the entity with the given UUID is not of type SceneObjectGroup 
+        }
+
+        public string GetSyncActorID()
+        {
+            if (m_DSGActorSyncModule != null)
+            {
+                return m_DSGActorSyncModule.ActorID;
+            }
+            return "";
+        }
+
+        //This function should only be called by an actor who's local Scene is just a cache of the authorative Scene.
+        //If the object already exists, use the new copy to replace it.
+        //Return true if added, false if just updated
+        public ObjectUpdateResult AddOrUpdateObjectBySynchronization(SceneObjectGroup sog)
+        {
+            return m_sceneGraph.AddOrUpdateObjectBySynchronization(sog);
+        }
+
+        //Similar to DeleteSceneObject, except that this does not change LastUpdateActorID and LastUpdateTimeStamp
+        public void DeleteSceneObjectBySynchronization(SceneObjectGroup group)
+        {
+            //            m_log.DebugFormat("[SCENE]: Deleting scene object {0} {1}", group.Name, group.UUID);
+
+            //SceneObjectPart rootPart = group.GetChildPart(group.UUID);
+
+            // Serialise calls to RemoveScriptInstances to avoid
+            // deadlocking on m_parts inside SceneObjectGroup
+            lock (m_deleting_scene_object)
+            {
+                group.RemoveScriptInstances(true);
+            }
+
+            SceneObjectPart[] partList = group.Parts;
+
+            foreach (SceneObjectPart part in partList)
+            {
+                if (part.IsJoint() && ((part.Flags & PrimFlags.Physics) != 0))
+                {
+                    PhysicsScene.RequestJointDeletion(part.Name); // FIXME: what if the name changed?
+                }
+                else if (part.PhysActor != null)
+                {
+                    PhysicsScene.RemovePrim(part.PhysActor);
+                    part.PhysActor = null;
+                }
+            }
+
+            if (UnlinkSceneObject(group, false))
+            {
+                EventManager.TriggerObjectBeingRemovedFromScene(group);
+                EventManager.TriggerParcelPrimCountTainted();
+            }
+
+            bool silent = false; //do not suppress broadcasting changes to other clients, for debugging with viewers
+            group.DeleteGroupFromScene(silent);
+
+        }
+
+        #endregion //SYMMETRIC SYNC
+
         public ICapabilitiesModule CapsModule
         {
             get { return m_capsModule; }
@@ -1265,6 +1362,16 @@ namespace OpenSim.Region.Framework.Scenes
             RegionSyncClientModule = RequestModuleInterface<IRegionSyncClientModule>();
             ScriptEngineToSceneConnectorModule = RequestModuleInterface<IScriptEngineToSceneConnectorModule>();
 
+            //////////////////////////////////////////////////////////////////////
+            //SYMMETRIC SYNC (KittyL: started 12/23/2010)
+            //////////////////////////////////////////////////////////////////////
+            m_regionSyncModule = RequestModuleInterface<IRegionSyncModule>();
+            m_DSGActorSyncModule = RequestModuleInterface<IDSGActorSyncModule>();
+
+            //////////////////////////////////////////////////////////////////////
+            //end of SYMMETRIC SYNC
+            //////////////////////////////////////////////////////////////////////
+            
             // Shoving this in here for now, because we have the needed
             // interfaces at this point
             //
@@ -1416,7 +1523,7 @@ namespace OpenSim.Region.Framework.Scenes
                     // If it's a client manager, just send prim updates
                     // This will get fixed later to only send to locally logged in presences rather than all presences
                     // but requires pulling apart the concept of a client from the concept of a presence/avatar
-                    if (IsSyncedClient() || !RegionSyncEnabled)
+                    if (IsSyncedClient())
 
                     {
                         ForEachScenePresence(delegate(ScenePresence sp) { sp.SendPrimUpdates(); });
@@ -1450,24 +1557,14 @@ namespace OpenSim.Region.Framework.Scenes
                         m_regionSyncServerModule.SendUpdates();
                     }
 
-                    /*
+                    //SYMMETRIC SYNC
-                    // The authoritative sim should not try to send coarse locations
+
-                    // Leave this up to the client managers
+                    //NOTE: If it is configured as symmetric sync in opensim.ini, the above IsSyncedServer() or IsSyncedClient() should all return false
-                    if (!IsSyncedServer())
+                    if (RegionSyncModule != null)
                     {
-                        if (m_frame % m_update_coarse_locations == 0)
+                        RegionSyncModule.SendSceneUpdates();
-                        {
-                            List<Vector3> coarseLocations;
-                            List<UUID> avatarUUIDs;
-                            SceneGraph.GetCoarseLocations(out coarseLocations, out avatarUUIDs, 60);
-                            // Send coarse locations to clients 
-                            ForEachScenePresence(delegate(ScenePresence presence)
-                            {
-                                presence.SendCoarseLocations(coarseLocations, avatarUUIDs);
-                            });
                     }
-                    }
+                    //end of SYMMETRIC SYNC
-                     * */
 
                     int tmpPhysicsMS2 = Util.EnvironmentTickCount();
                     // Do not simulate physics locally if this is a synced client
@@ -2317,6 +2414,15 @@ namespace OpenSim.Region.Framework.Scenes
             group.DeleteGroupFromScene(silent);
 
 //            m_log.DebugFormat("[SCENE]: Exit DeleteSceneObject() for {0} {1}", group.Name, group.UUID);            
+
+            //SYMMETRIC SYNC
+            //Set the ActorID and TimeStamp info for this latest update
+            foreach (SceneObjectPart part in group.Parts)
+            {
+                part.SyncInfoUpdate();
+            }
+            //end of SYMMETRIC SYNC
+
         }
 
         /// <summary>

OpenSim/Region/Framework/Scenes/SceneGraph.cs

@@ -373,23 +373,13 @@ namespace OpenSim.Region.Framework.Scenes
 
             sceneObject.AttachToScene(m_parentScene);
 
-            //KittyL: edited to support script engine actor
-            //if (sendClientUpdates)
-            //    sceneObject.ScheduleGroupForFullUpdate();
             if (sendClientUpdates)
-            {
                 sceneObject.ScheduleGroupForFullUpdate();
-            }
             
             Entities.Add(sceneObject);
 
-            //KittyL: edited to support script engine actor
+            if (attachToBackup)
-            //if (attachToBackup)
-            //    sceneObject.AttachToBackup();
-            if (attachToBackup && m_parentScene.IsAuthoritativeScene())
-            {
                 sceneObject.AttachToBackup();
-            }
             
             if (OnObjectCreate != null)
                 OnObjectCreate(sceneObject);
@@ -465,7 +455,10 @@ namespace OpenSim.Region.Framework.Scenes
         protected internal void AddToUpdateList(SceneObjectGroup obj)
         {
             lock (m_updateList)
+            {
                 m_updateList[obj.UUID] = obj;
+                m_log.Debug("added " + obj.UUID + " to m_updateList");
+            }
         }
 
         /// <summary>
@@ -484,6 +477,13 @@ namespace OpenSim.Region.Framework.Scenes
                 lock (m_updateList)
                 {
                     updates = new List<SceneObjectGroup>(m_updateList.Values);
+
+                    if (updates.Count > 0)
+                    {
+                        m_log.Debug("SceneGraph: " + updates.Count + " objects to send updates for");
+                    }
+
+
                     m_updateList.Clear();
                 }
 
@@ -1928,7 +1928,103 @@ namespace OpenSim.Region.Framework.Scenes
 
         }
 
-        #endregion
+        #endregion // REGION SYNC
 
+        #region SYMMETRIC SYNC
+
+        public Scene.ObjectUpdateResult AddOrUpdateObjectBySynchronization(SceneObjectGroup updatedSog)
+        {
+            UUID sogID = updatedSog.UUID;
+
+            if (Entities.ContainsKey(sogID))
+            {
+                //update the object
+                EntityBase entity = Entities[sogID];
+                if (entity is SceneObjectGroup)
+                {
+                    SceneObjectGroup localSog = (SceneObjectGroup)entity;
+                    Scene.ObjectUpdateResult updateResult = localSog.UpdateObjectAllProperties(updatedSog);
+                    return updateResult;
+                }
+                else
+                {
+                    m_log.Warn("Entity with " + sogID + " is not of type SceneObjectGroup");
+                    //return false;
+                    return Scene.ObjectUpdateResult.Error;
+                }
+            }
+            else
+            {
+                m_log.Debug("AddSceneObjectByStateSynch to be called");
+                AddSceneObjectByStateSynch(updatedSog);
+                return Scene.ObjectUpdateResult.New;
+            }
+        }
+
+        //This is an object added due to receiving a state synchronization message from Scene or an actor. Do similar things as the original AddSceneObject(),
+        //but call ScheduleGroupForFullUpdate_TimeStampUnchanged() instead, so as not to modify the timestamp or actorID, since the object was not created
+        //locally.
+        protected bool AddSceneObjectByStateSynch(SceneObjectGroup sceneObject)
+        {
+            if (sceneObject == null || sceneObject.RootPart == null || sceneObject.RootPart.UUID == UUID.Zero)
+                return false;
+
+            if (Entities.ContainsKey(sceneObject.UUID))
+                return false;
+
+            SceneObjectPart[] children = sceneObject.Parts;
+
+            // Clamp child prim sizes and add child prims to the m_numPrim count
+            if (m_parentScene.m_clampPrimSize)
+            {
+                foreach (SceneObjectPart part in children)
+                {
+                    Vector3 scale = part.Shape.Scale;
+
+                    if (scale.X > m_parentScene.m_maxNonphys)
+                        scale.X = m_parentScene.m_maxNonphys;
+                    if (scale.Y > m_parentScene.m_maxNonphys)
+                        scale.Y = m_parentScene.m_maxNonphys;
+                    if (scale.Z > m_parentScene.m_maxNonphys)
+                        scale.Z = m_parentScene.m_maxNonphys;
+
+                    part.Shape.Scale = scale;
+                }
+            }
+            m_numPrim += children.Length;
+
+            sceneObject.AttachToScene(m_parentScene);
+
+            //SYMMETRIC SYNC, 
+            sceneObject.ScheduleGroupForFullUpdate_SyncInfoUnchanged();
+            //end of SYMMETRIC SYNC, 
+
+            Entities.Add(sceneObject);
+
+            //ScenePersistenceSyncModule will attach the object to backup when it catches the OnObjectCreate event.
+            //if (attachToBackup)
+            //    sceneObject.AttachToBackup();
+
+            if (OnObjectCreate != null)
+                OnObjectCreate(sceneObject);
+
+            lock (SceneObjectGroupsByFullID)
+            {
+                SceneObjectGroupsByFullID[sceneObject.UUID] = sceneObject;
+                foreach (SceneObjectPart part in children)
+                    SceneObjectGroupsByFullID[part.UUID] = sceneObject;
+            }
+
+            lock (SceneObjectGroupsByLocalID)
+            {
+                SceneObjectGroupsByLocalID[sceneObject.LocalId] = sceneObject;
+                foreach (SceneObjectPart part in children)
+                    SceneObjectGroupsByLocalID[part.LocalId] = sceneObject;
+            }
+
+            return true;
+        }
+
+        #endregion //SYMMETRIC SYNC
     }
 }

OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs

@@ -3455,6 +3455,145 @@ namespace OpenSim.Region.Framework.Scenes
             this.m_locX = updatedSog.LocX;
             this.m_locY = updatedSog.LocY;
         }
+#endregion 
+
+        #region SYMMETRIC SYNC
+
+        //update the existing copy of the object with updated properties in 'updatedSog'
+        //NOTE: updates on script content are handled seperately (e.g. user edited the script and saved it) -- SESyncServerOnUpdateScript(), a handler of EventManager.OnUpdateScript        
+        //public void UpdateObjectProperties(SceneObjectGroup updatedSog)
+
+        /// <summary>
+        /// Update the existing copy of the object with updated properties in 'updatedSog'. For now we update 
+        /// all properties. Later on this should be edited to allow only updating a bucket of properties.
+        /// </summary>
+        /// <param name="updatedSog"></param>
+        /// <returns></returns>
+        public Scene.ObjectUpdateResult UpdateObjectAllProperties(SceneObjectGroup updatedSog)
+        {
+            if (!this.GroupID.Equals(updatedSog.GroupID))
+                return Scene.ObjectUpdateResult.Error;
+
+            ////////////////////////////////////////////////////////////////////////////////////////////////////
+            //NOTE!!! 
+            //We do not want to simply call SceneObjectGroup.Copy here to clone the object: 
+            //the prims (SceneObjectParts) in updatedSog are different instances than those in the local copy,
+            //and we want to preserve the references to the prims in this local copy, especially for scripts 
+            //of each prim, where the scripts have references to the local copy. If the local copy is replaced,
+            //the prims (parts) will be replaces and we need to update all the references that were pointing to 
+            //the previous prims.
+            ////////////////////////////////////////////////////////////////////////////////////////////////////
+
+            Scene.ObjectUpdateResult groupUpdateResult = Scene.ObjectUpdateResult.Unchanged;
+            Dictionary<UUID, SceneObjectPart> updatedParts = new Dictionary<UUID, SceneObjectPart>();
+            bool partsRemoved = false; //has any old part been removed?
+            bool rootPartChanged = false; //has the rootpart be changed to a different prim?
+
+            lock (m_parts)
+            {
+                //update rootpart, if changed
+                if (m_rootPart.UUID != updatedSog.RootPart.UUID)
+                {
+                    m_rootPart = updatedSog.RootPart;
+                    rootPartChanged = true;
+                }
+
+                //foreach (KeyValuePair<UUID, SceneObjectPart> pair in updatedSog.Parts)
+                foreach (SceneObjectPart updatedPart in updatedSog.Parts)
+                {
+                    UUID partUUID = updatedPart.UUID;
+                    Scene.ObjectUpdateResult partUpdateResult = Scene.ObjectUpdateResult.Unchanged;
+                    if (HasChildPrim(partUUID))
+                    {
+                        //update the existing part
+                        SceneObjectPart oldPart = GetChildPart(partUUID);
+                        partUpdateResult = oldPart.UpdateAllProperties(updatedPart);
+                        updatedParts.Add(partUUID, updatedPart);
+                    }
+                    else
+                    {
+                        //a new part
+                        //m_parts.Add(partUUID, updatedPart);
+                        AddPart(updatedPart);
+                        partUpdateResult = Scene.ObjectUpdateResult.New;
+                    }
+
+                    if (partUpdateResult != Scene.ObjectUpdateResult.Unchanged)
+                    {
+                        if (partUpdateResult == Scene.ObjectUpdateResult.New)
+                            groupUpdateResult = Scene.ObjectUpdateResult.Updated;
+                        else
+                            groupUpdateResult = partUpdateResult; //Error or Updated
+                    }
+                }
+
+                //For any parts that are not in the updatesParts (the old parts that are still in updatedSog), delete them.
+                foreach (SceneObjectPart oldPart in this.Parts)
+                {
+                    if (!updatedParts.ContainsKey(oldPart.UUID))
+                    {
+                        m_parts.Remove(oldPart.UUID);
+                        partsRemoved = true;
+                    }
+                }
+
+                //Update the rootpart's ID in each non root parts
+                if (rootPartChanged)
+                {
+                    UpdateParentIDs();
+                }
+            }
+
+            if (partsRemoved)
+            {
+                groupUpdateResult = Scene.ObjectUpdateResult.Updated;
+            }
+
+            /*
+            //update the authoritative scene that this object is located, which is identified by (LocX, LocY)
+            if (this.m_locX != updatedSog.LocX)
+            {
+                this.m_locX = updatedSog.LocX;
+                groupUpdateResult = Scene.ObjectUpdateResult.Updated;
+            }
+            if (this.m_locY != updatedSog.LocY)
+            {
+                this.m_locY = updatedSog.LocY;
+                groupUpdateResult = Scene.ObjectUpdateResult.Updated;
+            }
+             * */
+
+            //Schedule updates to be sent out, if the local copy has just been updated
+            //(1) if we are debugging the actor with a viewer attaching to it,
+            //we need to schedule updates to be sent to the viewer.
+            //(2) or if we are a relaying node to relay updates, we need to forward the updates.
+            //NOTE: LastUpdateTimeStamp and LastUpdateActorID should be kept the same as in the received copy of the object.
+            if (groupUpdateResult == Scene.ObjectUpdateResult.Updated)
+            {
+                ScheduleGroupForFullUpdate_SyncInfoUnchanged();
+            }
+
+            return groupUpdateResult;
+        }
+
+        public void ScheduleGroupForFullUpdate_SyncInfoUnchanged()
+        {
+            if (IsAttachment)
+                m_log.DebugFormat("[SOG]: Scheduling full update for {0} {1}", Name, LocalId);
+
+            checkAtTargets();
+            RootPart.ScheduleFullUpdate_SyncInfoUnchanged();
+
+            lock (m_parts)
+            {
+                foreach (SceneObjectPart part in this.Parts)
+                {
+                    if (part != RootPart)
+                        part.ScheduleFullUpdate_SyncInfoUnchanged();
+                }
+            }
+        }
+
         #endregion
     }
 }

OpenSim/Region/Framework/Scenes/SceneObjectPart.cs

@@ -2892,6 +2892,13 @@ namespace OpenSim.Region.Framework.Scenes
             //            m_log.DebugFormat(
             //                "[SCENE OBJECT PART]: Scheduling full  update for {0}, {1} at {2}",
             //                UUID, Name, TimeStampFull);
+
+            //SYMMETRIC SYNC
+
+            //update information (timestamp, actorID, etc) needed for synchronization across copies of Scene
+            SyncInfoUpdate();
+            
+            //end of SYMMETRIC SYNC
         }
 
         /// <summary>
@@ -2913,6 +2920,13 @@ namespace OpenSim.Region.Framework.Scenes
             //                m_log.DebugFormat(
             //                    "[SCENE OBJECT PART]: Scheduling terse update for {0}, {1} at {2}",
             //                    UUID, Name, TimeStampTerse);
+
+                //SYMMETRIC SYNC
+
+                //update information (timestamp, actorID, etc) needed for synchronization across copies of Scene
+                SyncInfoUpdate();
+
+                //end of SYMMETRIC SYNC
             }
         }
 
@@ -3130,6 +3144,12 @@ namespace OpenSim.Region.Framework.Scenes
                 }
             }
             ClearUpdateSchedule();
+
+            //SYMMETRIC SYNC
+
+            m_parentGroup.Scene.RegionSyncModule.QueueSceneObjectPartForUpdate(this);
+            
+            //end of SYMMETRIC SYNC
         }
 
         /// <summary>
@@ -4888,5 +4908,208 @@ namespace OpenSim.Region.Framework.Scenes
 
         #endregion
 
+        #region SYMMETRIC SYNC
+
+        //Time stamp for the most recent update on this prim. We only have one time-stamp per prim for now.
+        //The goal is to evetually have time-stamp per property bucket for each prim.
+        private long m_lastUpdateTimeStamp = DateTime.Now.Ticks;
+        public long LastUpdateTimeStamp
+        {
+            get { return m_lastUpdateTimeStamp; }
+            set { m_lastUpdateTimeStamp = value; }
+        }
+
+        //The ID the identifies which actor has caused the most recent update to the prim.
+        //We use type "string" for the ID only to make it human-readable. 
+        private string m_lastUpdateActorID;
+        public string LastUpdateActorID
+        {
+            get { return m_lastUpdateActorID; }
+            set { m_lastUpdateActorID = value; }
+        }
+
+        public void UpdateTimestamp()
+        {
+            m_lastUpdateTimeStamp = DateTime.Now.Ticks;
+        }
+
+        public void SetLastUpdateActorID()
+        {
+            if (m_parentGroup != null)
+            {
+                m_lastUpdateActorID = m_parentGroup.Scene.ActorSyncModule.ActorID;
+            }
+            else
+            {
+                m_log.Error("Prim " + UUID + " is not in a SceneObjectGroup yet");
+            }
+        }
+
+        public void SyncInfoUpdate()
+        {
+            //Trick: calling UpdateTimestamp here makes sure that when an object was received and de-serialized, before
+            //       its parts are linked together, neither TimeStamp or ActorID will be modified. This is because during de-serialization, 
+            //       ScheduleFullUpdate() is called when m_parentGroup == null
+            if (m_parentGroup != null)
+            {
+                UpdateTimestamp();
+                m_lastUpdateActorID = m_parentGroup.Scene.ActorSyncModule.ActorID;
+            }
+        }
+
+        //!!!!!! -- TODO: 
+        //!!!!!! -- We should call UpdateXXX functions to update each property, cause some of such updates involves sanity checking.
+        public Scene.ObjectUpdateResult UpdateAllProperties(SceneObjectPart updatedPart)
+        {
+            ////////////////////////////////////////////////////////////////////////////////////////////////////
+            //NOTE!!!: So far this function is written with Script Engine updating local Scene cache in mind.
+            ////////////////////////////////////////////////////////////////////////////////////////////////////
+
+            ////////////////////Assumptions: ////////////////////
+            //(1) prim's UUID and LocalID shall not change (UUID is the unique identifies, LocalID is used to refer to the prim by, say scripts)
+            //(2) RegionHandle won't be updated -- each copy of Scene is hosted on a region with different region handle
+            //(3) ParentID won't be updated -- if the rootpart of the SceneObjectGroup changed, that will be updated in SceneObjectGroup.UpdateObjectProperties
+
+            ////////////////////Furture enhancements:////////////////////
+            //For now, we only update the set of properties that are included in serialization. 
+            //See SceneObjectSerializer for the properties that are included in a serialized SceneObjectPart.
+            //Later on, we may implement update functions that allow updating certain properties or certain buckets of properties.
+
+            if (updatedPart == null)
+                return Scene.ObjectUpdateResult.Error;
+
+            if (m_lastUpdateTimeStamp > updatedPart.LastUpdateTimeStamp)
+            {
+                //Our timestamp is more update to date, keep our values of the properties. Do not update anything.
+                return Scene.ObjectUpdateResult.Unchanged;
+            }
+
+            if (m_lastUpdateTimeStamp == updatedPart.LastUpdateTimeStamp)
+            {
+                //if (m_parentGroup.Scene.GetActorID() != updatedPart.LastUpdatedByActorID)
+                if (m_lastUpdateActorID != updatedPart.LastUpdateActorID)
+                {
+                    m_log.Warn("Different actors modified SceneObjetPart " + UUID + " with the same TimeStamp, CONFLICT RESOLUTION TO BE IMPLEMENTED!!!!");
+                    return Scene.ObjectUpdateResult.Unchanged;
+                }
+
+                //My own update was relayed back. Don't relay it.
+                return Scene.ObjectUpdateResult.Unchanged;
+            }
+
+            //Otherwise, our timestamp is less up to date, update the prim with the received copy
+
+            Scene.ObjectUpdateResult partUpdateResult = Scene.ObjectUpdateResult.Updated;
+
+            //See SceneObjectSerializer for the properties that are included in a serialized SceneObjectPart.
+            this.AllowedDrop = updatedPart.AllowedDrop;
+            this.CreatorID = updatedPart.CreatorID;
+            this.CreatorData = updatedPart.CreatorData;
+            this.FolderID = updatedPart.FolderID;
+            this.InventorySerial = updatedPart.InventorySerial;
+            this.TaskInventory = updatedPart.TaskInventory;
+            //Following two properties, UUID and LocalId, shall not be updated.
+            //this.UUID 
+            //this.LocalId
+            this.Name = updatedPart.Name;
+            this.Material = updatedPart.Material;
+            this.PassTouches = updatedPart.PassTouches;
+            //RegionHandle shall not be copied, since updatedSog is sent by a different actor, which has a different local region
+            //this.RegionHandle 
+            this.ScriptAccessPin = updatedPart.ScriptAccessPin;
+            this.GroupPosition = updatedPart.GroupPosition;
+            this.OffsetPosition = updatedPart.OffsetPosition;
+            this.RotationOffset = updatedPart.RotationOffset;
+            this.Velocity = updatedPart.Velocity;
+            this.AngularVelocity = updatedPart.AngularVelocity;
+            this.Acceleration = updatedPart.Acceleration;
+            this.Description = updatedPart.Description;
+            this.Color = updatedPart.Color;
+            this.Text = updatedPart.Text;
+            this.SitName = updatedPart.SitName;
+            this.TouchName = updatedPart.TouchName;
+            this.LinkNum = updatedPart.LinkNum;
+            this.ClickAction = updatedPart.ClickAction;
+            this.Shape = updatedPart.Shape;
+            this.Scale = updatedPart.Scale;
+            this.UpdateFlag = updatedPart.UpdateFlag;
+            this.SitTargetOrientation = updatedPart.SitTargetOrientation;
+            this.SitTargetPosition = updatedPart.SitTargetPosition;
+            this.SitTargetPositionLL = updatedPart.SitTargetPositionLL;
+            this.SitTargetOrientationLL = updatedPart.SitTargetOrientationLL;
+            //ParentID should still point to the rootpart in the local sog, do not update. If the root part changed, we will update it in SceneObjectGroup.UpdateObjectProperties()
+            //this.ParentID;
+            this.CreationDate = updatedPart.CreationDate;
+            this.Category = updatedPart.Category;
+            this.SalePrice = updatedPart.SalePrice;
+            this.ObjectSaleType = updatedPart.ObjectSaleType;
+            this.OwnershipCost = updatedPart.OwnershipCost;
+            this.GroupID = updatedPart.GroupID;
+            this.OwnerID = updatedPart.OwnerID;
+            this.LastOwnerID = updatedPart.LastOwnerID;
+            this.BaseMask = updatedPart.BaseMask;
+            this.OwnerMask = updatedPart.OwnerMask;
+            this.GroupMask = updatedPart.GroupMask;
+            this.EveryoneMask = updatedPart.EveryoneMask;
+            this.NextOwnerMask = updatedPart.NextOwnerMask;
+            this.Flags = updatedPart.Flags;
+            this.CollisionSound = updatedPart.CollisionSound;
+            this.CollisionSoundVolume = updatedPart.CollisionSoundVolume;
+            this.MediaUrl = updatedPart.MediaUrl;
+            this.TextureAnimation = updatedPart.TextureAnimation;
+            this.ParticleSystem = updatedPart.ParticleSystem;
+
+            //Update the timestamp and LastUpdatedByActorID first.
+            this.m_lastUpdateActorID = updatedPart.LastUpdateActorID;
+            this.m_lastUpdateTimeStamp = updatedPart.LastUpdateTimeStamp;
+
+
+            /*
+            this.m_inventory.Items = (TaskInventoryDictionary)updatedPart.m_inventory.Items.Clone();
+            //update shape information, for now, only update fileds in Shape whose set functions are defined in PrimitiveBaseShape
+            this.Shape = updatedPart.Shape.Copy();
+            this.Shape.TextureEntry = updatedPart.Shape.TextureEntry;
+             * */
+
+            return partUpdateResult;
+        }
+
+        /// <summary>
+        /// Schedules this prim for a full update, without changing the timestamp or actorID (info on when and who modified any property).
+        /// NOTE: this is the same as the original SceneObjectPart.ScheduleFullUpdate().
+        /// </summary>
+        public void ScheduleFullUpdate_SyncInfoUnchanged()
+        {
+            m_log.DebugFormat("[SCENE OBJECT PART]: ScheduleFullUpdate_SyncInfoUnchanged for {0} {1}", Name, LocalId);
+
+            if (m_parentGroup != null)
+            {
+                m_parentGroup.QueueForUpdateCheck();
+            }
+
+            int timeNow = Util.UnixTimeSinceEpoch();
+
+            // If multiple updates are scheduled on the same second, we still need to perform all of them
+            // So we'll force the issue by bumping up the timestamp so that later processing sees these need
+            // to be performed.
+            if (timeNow <= TimeStampFull)
+            {
+                TimeStampFull += 1;
+            }
+            else
+            {
+                TimeStampFull = (uint)timeNow;
+            }
+
+            m_updateFlag = 2;
+
+            //            m_log.DebugFormat(
+            //                "[SCENE OBJECT PART]: Scheduling full  update for {0}, {1} at {2}",
+            //                UUID, Name, TimeStampFull);
+
+        }
+
+        #endregion 
+
     }
 }

OpenSim/Region/Framework/Scenes/Serialization/SceneObjectSerializer.cs

@@ -215,6 +215,10 @@ namespace OpenSim.Region.Framework.Scenes.Serialization
 
                     sceneObject.AddPart(part);
 
+                    //SYMMETRIC SYNC
+                    //KittyL: 12/27/2010, added ActorID for symmetric synch model
+                    part.SetLastUpdateActorID();
+
                     // SceneObjectGroup.AddPart() tries to be smart and automatically set the LinkNum.
                     // We override that here
                     if (originalLinkNum != 0)
@@ -324,6 +328,12 @@ namespace OpenSim.Region.Framework.Scenes.Serialization
             m_SOPXmlProcessors.Add("MediaUrl", ProcessMediaUrl);
             m_SOPXmlProcessors.Add("TextureAnimation", ProcessTextureAnimation);
             m_SOPXmlProcessors.Add("ParticleSystem", ProcessParticleSystem);
+
+            //SYMMETRIC SYNC
+            m_SOPXmlProcessors.Add("LastUpdateTimeStamp", ProcessUpdateTimeStamp);
+            m_SOPXmlProcessors.Add("LastUpdateActorID", ProcessLastUpdateActorID);
+            //end of SYMMETRIC SYNC
+
             #endregion
 
             #region TaskInventoryXmlProcessors initialization
@@ -681,6 +691,19 @@ namespace OpenSim.Region.Framework.Scenes.Serialization
         {
             obj.ParticleSystem = Convert.FromBase64String(reader.ReadElementContentAsString("ParticleSystem", String.Empty));
         }
+
+        //SYMMETRIC SYNC
+        private static void ProcessUpdateTimeStamp(SceneObjectPart obj, XmlTextReader reader)
+        {
+            obj.LastUpdateTimeStamp = reader.ReadElementContentAsLong("LastUpdateTimeStamp", string.Empty);
+        }
+
+        private static void ProcessLastUpdateActorID(SceneObjectPart obj, XmlTextReader reader)
+        {
+            obj.LastUpdateActorID = reader.ReadElementContentAsString("LastUpdateActorID", string.Empty);
+        }
+        //end of SYMMETRIC SYNC
+
         #endregion
 
         #region TaskInventoryXmlProcessors
@@ -1159,6 +1182,11 @@ namespace OpenSim.Region.Framework.Scenes.Serialization
             WriteBytes(writer, "TextureAnimation", sop.TextureAnimation);
             WriteBytes(writer, "ParticleSystem", sop.ParticleSystem);
 
+            //SYMMETRIC SYNC
+            writer.WriteElementString("LastUpdateTimeStamp", sop.LastUpdateTimeStamp.ToString());
+            writer.WriteElementString("LastUpdateActorID", sop.LastUpdateActorID);
+            //end of SYMMETRIC SYNC
+
             writer.WriteEndElement();
         }
 

bin/config-include/SimianGrid.ini

@@ -65,7 +65,8 @@
     AssetLoaderArgs = "assets/AssetSets.xml"
 
 [Groups]
-    Enabled = true
+    ;Enabled = true
+    Enabled = false
     Module  = GroupsModule
     DebugEnabled     = false
     NoticesEnabled   = true