* The rest of the fix necessary for mantis #766 - terse updates broken

* Even very rapid linking/delinking should now behave normally.  Terse updates still occur as before
* Hopefully this ends the recent linking problems - please let us know if there are more

OpenSim/Region/Environment/Scenes/SceneObjectGroup.cs

@@ -948,7 +948,18 @@ namespace OpenSim.Region.Environment.Scenes
         public void LinkToGroup(SceneObjectGroup objectGroup)
         {
             if (objectGroup.RootPart.UpdateFlag > 0)
+            {
+                // I've never actually seen this happen, though I think it's theoretically possible                
+                m_log.ErrorFormat(
+                    "[SCENE OBJECT GROUP]: Aborted linking {0}, {1} to {2}, {3} as it has yet to finish delinking", 
+                    objectGroup.RootPart.Name, objectGroup.RootPart.UUID, RootPart.Name, RootPart.UUID);
+                                
                 return;
+            }
+            
+//            m_log.DebugFormat(
+//                "[SCENE OBJECT GROUP]: Linking group with root part {0}, {1} to group with root part {2}, {3}", 
+//                objectGroup.RootPart.Name, objectGroup.RootPart.UUID, RootPart.Name, RootPart.UUID);
 
             SceneObjectPart linkPart = objectGroup.m_rootPart;
             
@@ -1017,13 +1028,25 @@ namespace OpenSim.Region.Environment.Scenes
         /// <param name="partID"></param>
         public void DelinkFromGroup(uint partID)
         {
+            // Don't try and update if we're already in the middle of updating
             if (RootPart.UpdateFlag > 0)
+            {
+                // I've never actually seen this happen, though I think it's theoretically possible
+                m_log.WarnFormat(
+                    "[SCENE OBJECT GROUP]: Aborted delink update for {0}, {1} as it has yet to finish linking", 
+                    RootPart.Name, RootPart.UUID);
+                
                 return;
+            }
             
             SceneObjectPart linkPart = GetChildPart(partID);
 
             if (null != linkPart)
             {      
+//                m_log.DebugFormat(
+//                    "[SCENE OBJECT GROUP]: Delinking part {0}, {1} from group with root part {2}, {3}", 
+//                    linkPart.Name, linkPart.UUID, RootPart.Name, RootPart.UUID);
+                
                 LLQuaternion worldRot = linkPart.GetWorldRotation();  
     
                 // Remove the part from this object
@@ -1645,7 +1668,7 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         /// <summary>
-        /// 
+        /// Send a full update to the client for the given part
         /// </summary>
         /// <param name="remoteClient"></param>
         /// <param name="part"></param>
@@ -1662,7 +1685,7 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         /// <summary>
-        /// 
+        /// Send a terse update to the client for the given part
         /// </summary>
         /// <param name="remoteClient"></param>
         /// <param name="part"></param>

OpenSim/Region/Environment/Scenes/SceneObjectPart.cs

@@ -270,7 +270,6 @@ namespace OpenSim.Region.Environment.Scenes
                     m_groupPosition.Y = PhysActor.Position.Y;
                     m_groupPosition.Z = PhysActor.Position.Z;
                 }
-
                 return m_groupPosition;
             }
             set
@@ -1116,7 +1115,10 @@ namespace OpenSim.Region.Environment.Scenes
             
             int timeNow = Util.UnixTimeSinceEpoch();
                         
-            if (timeNow == TimeStampFull)
+            // 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 peformed.
+            if (timeNow <= TimeStampFull)
             {
                 TimeStampFull += 1;
             }
@@ -1126,6 +1128,10 @@ namespace OpenSim.Region.Environment.Scenes
             }
             
             m_updateFlag = 2;
+            
+//            m_log.DebugFormat(
+//                "[SCENE OBJECT PART]: Scheduling full  update for {0}, {1} at {2}", 
+//                UUID, Name, TimeStampFull);
         }
 
         public void AddFlag(LLObject.ObjectFlags flag)
@@ -1155,7 +1161,8 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         /// <summary>
-        /// 
+        /// Schedule a terse update for this prim.  Terse updates only send position,
+        /// rotation, velocity, rotational velocity and shape information.
         /// </summary>
         public void ScheduleTerseUpdate()
         {
@@ -1169,6 +1176,9 @@ namespace OpenSim.Region.Environment.Scenes
                 TimeStampTerse = (uint) Util.UnixTimeSinceEpoch();
                 m_updateFlag = 1;
 
+//                m_log.DebugFormat(
+//                    "[SCENE OBJECT PART]: Scheduling terse update for {0}, {1} at {2}", 
+//                    UUID, Name, TimeStampTerse);
             }
         }
 
@@ -1836,7 +1846,7 @@ namespace OpenSim.Region.Environment.Scenes
         }
 
         /// <summary>
-        /// 
+        /// Send a terse update to the client.
         /// </summary>
         /// <param name="remoteClient"></param>
         public void SendTerseUpdate(IClientAPI remoteClient)

OpenSim/Region/Environment/Scenes/ScenePresence.cs

@@ -472,20 +472,14 @@ namespace OpenSim.Region.Environment.Scenes
                     {
                         ScenePartUpdate update = m_updateTimes[part.UUID];
 
-                        // Two updates can occur with the same timestamp (especially
+                        // We deal with the possibility that two updates occur at the same unix time
-                        // since our timestamp resolution is to the nearest second).  Therefore, we still need
+                        // at the update point itself.
-                        // to send an update even if the last full update time is identical to the part's 
-                        // update timestamp.
-                        //
-                        // If we don't do this, various events (such as linking and delinking in the same
-                        // second), will stop working properly!
                         if (update.LastFullUpdateTime < part.TimeStampFull)
                         {
 //                            m_log.DebugFormat(
 //                                "[SCENE PRESENCE]: Fully   updating prim {0}, {1} - part timestamp {2}", 
 //                                part.Name, part.UUID, part.TimeStampFull);
                             
-                            //need to do a full update
                             part.SendFullUpdate(ControllingClient, GenerateClientFlags(part.UUID));
 
                             // We'll update to the part's timestamp rather than the current time to