From 43220afda2a69e7849c2ab9f98dcbd61a3da218b Mon Sep 17 00:00:00 2001
From: Justin Clark-Casey (justincc)
Date: Wed, 13 Mar 2013 23:42:14 +0000
Subject: Improve DAExampleModule to show current necessary locking to avoid
 race conditions with a serialization thread.

---
 .../Framework/DynamicAttributes/DAExampleModule.cs | 24 ++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

(limited to 'OpenSim/Region/CoreModules/Framework/DynamicAttributes')

diff --git a/OpenSim/Region/CoreModules/Framework/DynamicAttributes/DAExampleModule.cs b/OpenSim/Region/CoreModules/Framework/DynamicAttributes/DAExampleModule.cs
index 37131b9..f874495 100644
--- a/OpenSim/Region/CoreModules/Framework/DynamicAttributes/DAExampleModule.cs
+++ b/OpenSim/Region/CoreModules/Framework/DynamicAttributes/DAExampleModule.cs
@@ -85,19 +85,27 @@ namespace OpenSim.Region.Framework.DynamicAttributes.DAExampleModule
         {
             OSDMap attrs = null;
             SceneObjectPart sop = m_scene.GetSceneObjectPart(groupId);
+
+            if (sop == null)
+                return true;
+
             if (!sop.DynAttrs.TryGetValue(Name, out attrs))
                 attrs = new OSDMap();
             
             OSDInteger newValue;
-                
-            if (!attrs.ContainsKey("moves"))
-                newValue = new OSDInteger(1);
-            else
-                newValue = new OSDInteger(((OSDInteger)attrs["moves"]).AsInteger() + 1);
-                    
-            attrs["moves"] = newValue;
 
-            sop.DynAttrs[Name] = attrs;
+            // We have to lock on the entire dynamic attributes map to avoid race conditions with serialization code.
+            lock (sop.DynAttrs)            
+            {
+                if (!attrs.ContainsKey("moves"))
+                    newValue = new OSDInteger(1);
+                else
+                    newValue = new OSDInteger(attrs["moves"].AsInteger() + 1);
+                        
+                attrs["moves"] = newValue;
+
+                sop.DynAttrs[Name] = attrs;
+            }
     
             m_dialogMod.SendGeneralAlert(string.Format("{0} {1} moved {2} times", sop.Name, sop.UUID, newValue));
             
-- 
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