add LSL_Integer osGetLinkNumber(LSL_String name). uses a cache for the string to linknumber map, cache invalidations may still be missing :(

OpenSim/Region/Framework/Scenes/SceneGraph.cs

@@ -1985,6 +1985,7 @@ namespace OpenSim.Region.Framework.Scenes
                     {
                         newRoot.TriggerScriptChangedEvent(Changed.LINK);
                         newRoot.ParentGroup.HasGroupChanged = true;
+                        newRoot.ParentGroup.InvalidatePartsLinkMaps();
                         newRoot.ParentGroup.ScheduleGroupForFullUpdate();
                     }
                 }
@@ -2001,6 +2002,7 @@ namespace OpenSim.Region.Framework.Scenes
                     // from the database. They will be rewritten immediately,
                     // minus the rows for the unlinked child prims.
                     m_parentScene.SimulationDataService.RemoveObject(g.UUID, m_parentScene.RegionInfo.RegionID);
+                    g.InvalidatePartsLinkMaps();
                     g.TriggerScriptChangedEvent(Changed.LINK);
                     g.HasGroupChanged = true; // Persist
                     g.ScheduleGroupForFullUpdate();

OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs

@@ -2004,6 +2004,7 @@ namespace OpenSim.Region.Framework.Scenes
 
             if (part.LinkNum == 2)
                 RootPart.LinkNum = 1;
+            InvalidatePartsLinkMaps();
         }
 
         /// <summary>
@@ -2560,6 +2561,7 @@ namespace OpenSim.Region.Framework.Scenes
                 dupe.ScheduleGroupForFullUpdate();
             }
 
+            dupe.InvalidatePartsLinkMaps();
             m_dupeInProgress = false;
             return dupe;
         }
@@ -3321,6 +3323,7 @@ namespace OpenSim.Region.Framework.Scenes
             ResetChildPrimPhysicsPositions();
 
             InvalidBoundsRadius();
+            InvalidatePartsLinkMaps();
 
             if (m_rootPart.PhysActor != null)
                 m_rootPart.PhysActor.Building = false;
@@ -3477,6 +3480,7 @@ namespace OpenSim.Region.Framework.Scenes
             objectGroup.HasGroupChangedDueToDelink = true;
 
             InvalidBoundsRadius();
+            InvalidatePartsLinkMaps();
             objectGroup.AggregatePerms();
 
             if (sendEvents)
@@ -5333,6 +5337,63 @@ namespace OpenSim.Region.Framework.Scenes
             m_PlaySoundSlavePrims.Clear();
             m_LoopSoundMasterPrim = null;
             m_targets.Clear();
+            m_partsNameToLinkMap.Clear();
+        }
+
+        Dictionary<string,int> m_partsNameToLinkMap = new Dictionary<string, int>();
+
+        // this scales bad but so does GetLinkNumPart
+        public int GetLinkNumber(string name)
+        {
+            if(String.IsNullOrEmpty(name) || name == "Object")
+                return -1;
+
+            lock(m_partsNameToLinkMap)
+            {
+                if(m_partsNameToLinkMap.Count == 0)
+                {
+                    SceneObjectPart[] parts = m_parts.GetArray();
+                    for (int i = 0; i < parts.Length; i++)
+                    {
+                        string s = parts[i].Name;
+                        if(String.IsNullOrEmpty(s) || s == "Object" || s == "Primitive")
+                            continue;
+
+                        if(m_partsNameToLinkMap.ContainsKey(s))
+                        {
+                            int ol = parts[i].LinkNum;
+                            if(ol < m_partsNameToLinkMap[s])
+                                m_partsNameToLinkMap[s] = ol;
+                        }
+                        else
+                            m_partsNameToLinkMap[s] = parts[i].LinkNum;
+                    }
+                }
+
+                if(m_partsNameToLinkMap.ContainsKey(name))
+                    return m_partsNameToLinkMap[name];
+            }
+
+            if(m_sittingAvatars.Count > 0)
+            {
+                int j = m_parts.Count;
+                if(j > 1)
+                    j++;
+                ScenePresence[] avs = m_sittingAvatars.ToArray();
+                for (int i = 0; i < avs.Length; i++, j++)
+                {
+                    if (avs[i].Name == name)
+                        return j;
+                }
+            }
+
+            return -1;
+        }
+
+        public void InvalidatePartsLinkMaps()
+        {
+            lock(m_partsNameToLinkMap)
+                m_partsNameToLinkMap.Clear();
         }
 
         #endregion

OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs

@@ -4663,5 +4663,14 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             sog.TeleportObject(myid, targetPos, rotation, flags);
             // a delay here may break vehicles
         }
+
+        public LSL_Integer osGetLinkNumber(LSL_String name)
+        {
+            m_host.AddScriptLPS(1);
+            SceneObjectGroup sog = m_host.ParentGroup;
+            if(sog== null || sog.IsDeleted)
+                return -1;
+            return sog.GetLinkNumber(name);
+        }
     }
 }

OpenSim/Region/ScriptEngine/Shared/Api/Runtime/OSSL_Stub.cs

@@ -1144,5 +1144,10 @@ namespace OpenSim.Region.ScriptEngine.Shared.ScriptBase
         {
             m_OSSL_Functions.osTeleportObject(objectUUID, targetPos, targetrotation, flags);
         }
+
+        public LSL_Integer osGetLinkNumber(LSL_String name)
+        {
+            return m_OSSL_Functions.osGetLinkNumber(name);
+        }
     }
 }