From efcf00ee60c48b81d88ea48e31162e4fd97575f5 Mon Sep 17 00:00:00 2001
From: Sean Dague
Date: Thu, 5 Feb 2009 16:12:51 +0000
Subject: From: Christopher Yeoh <yeohc@au1.ibm.com>

This patch fixes the problem where if an object containing a script is
deleted at the same time as an object containing the same script is
rezzed, it can result in the assembly file being deleted after the
second object script initialisation has found it but not started using
it yet, resulting in the script not starting up.

---
 OpenSim/Region/ScriptEngine/XEngine/XEngine.cs | 63 +++++++++++++++++++-------
 1 file changed, 46 insertions(+), 17 deletions(-)

diff --git a/OpenSim/Region/ScriptEngine/XEngine/XEngine.cs b/OpenSim/Region/ScriptEngine/XEngine/XEngine.cs
index 7a52205..f0f867b 100644
--- a/OpenSim/Region/ScriptEngine/XEngine/XEngine.cs
+++ b/OpenSim/Region/ScriptEngine/XEngine/XEngine.cs
@@ -100,6 +100,9 @@ namespace OpenSim.Region.ScriptEngine.XEngine
         private Dictionary<UUID, string> m_Assemblies =
                 new Dictionary<UUID, string>();
 
+        private Dictionary<string, int> m_AddingAssemblies =
+                new Dictionary<string, int>();
+
         // This will list AppDomains by script asset
 
         private Dictionary<UUID, AppDomain> m_AppDomains =
@@ -509,8 +512,16 @@ namespace OpenSim.Region.ScriptEngine.XEngine
 
             try
             {
-                assembly = m_Compiler.PerformScriptCompile(script,
-                                                           assetID.ToString());
+                lock (m_AddingAssemblies) 
+                {
+                    assembly = m_Compiler.PerformScriptCompile(script,
+                                                               assetID.ToString());
+                    if (!m_AddingAssemblies.ContainsKey(assembly)) {
+                        m_AddingAssemblies[assembly] = 1;
+                    } else {
+                        m_AddingAssemblies[assembly]++;
+                    }
+                }
             }
             catch (Exception e)
             {
@@ -592,6 +603,10 @@ namespace OpenSim.Region.ScriptEngine.XEngine
                             m_log.ErrorFormat("[XEngine] Exception creating app domain:\n {0}", e.ToString());
                             m_ScriptErrorMessage += "Exception creating app domain:\n";
                             m_ScriptFailCount++;
+                            lock (m_AddingAssemblies) 
+                            {
+                                m_AddingAssemblies[assembly]--;
+                            }
                             return false;
                         }
                     }
@@ -626,6 +641,11 @@ namespace OpenSim.Region.ScriptEngine.XEngine
                 if (!m_Assemblies.ContainsKey(assetID))
                     m_Assemblies[assetID] = assembly;
 
+                lock (m_AddingAssemblies) 
+                {
+                    m_AddingAssemblies[assembly]--;
+                }
+
                 if (instance!=null) 
                     instance.Init();
             }
@@ -710,24 +730,33 @@ namespace OpenSim.Region.ScriptEngine.XEngine
                     assetIDList.Remove(i.AssetID);
             }
 
-            foreach (UUID assetID in assetIDList)
+            lock (m_AddingAssemblies)
             {
-//                m_log.DebugFormat("[XEngine] Removing unreferenced assembly {0}", m_Assemblies[assetID]);
-                try
-                {
-                    if (File.Exists(m_Assemblies[assetID]))
-                        File.Delete(m_Assemblies[assetID]);
-
-                    if (File.Exists(m_Assemblies[assetID]+".state"))
-                        File.Delete(m_Assemblies[assetID]+".state");
-
-                    if (File.Exists(m_Assemblies[assetID]+".mdb"))
-                        File.Delete(m_Assemblies[assetID]+".mdb");
-                }
-                catch (Exception)
+                foreach (UUID assetID in assetIDList)
                 {
+                    // Do not remove assembly files if another instance of the script
+                    // is currently initialising
+                    if (!m_AddingAssemblies.ContainsKey(m_Assemblies[assetID])
+                        || m_AddingAssemblies[m_Assemblies[assetID]] == 0) 
+                    {
+//                        m_log.DebugFormat("[XEngine] Removing unreferenced assembly {0}", m_Assemblies[assetID]);
+                        try
+                        {
+                            if (File.Exists(m_Assemblies[assetID]))
+                                File.Delete(m_Assemblies[assetID]);
+                            
+                            if (File.Exists(m_Assemblies[assetID]+".state"))
+                                File.Delete(m_Assemblies[assetID]+".state");
+                            
+                            if (File.Exists(m_Assemblies[assetID]+".mdb"))
+                                File.Delete(m_Assemblies[assetID]+".mdb");
+                        }
+                        catch (Exception)
+                        {
+                        }
+                        m_Assemblies.Remove(assetID);
+                    }
                 }
-                m_Assemblies.Remove(assetID);
             }
         }
 
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