From f0996fa47d43346c7b88cf833ae24c6a98235981 Mon Sep 17 00:00:00 2001
From: mfranz <mfranz>
Date: Thu, 26 Jan 2006 00:18:27 +0000
Subject: [PATCH] create a new context for listener functions to avoid context
 corruption (caused a crash when a timer triggered a listener) ... Idea and OK
 by Andy

---
 src/Scripting/NasalSys.cxx |  3 ++-
 src/Scripting/NasalSys.hxx | 11 ++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/Scripting/NasalSys.cxx b/src/Scripting/NasalSys.cxx
index 4bbe08295..6b30376e3 100644
--- a/src/Scripting/NasalSys.cxx
+++ b/src/Scripting/NasalSys.cxx
@@ -617,7 +617,8 @@ void FGNasalSys::setListener(int argc, naRef* args)
     if(!(naIsCode(handler) || naIsCCode(handler) || naIsFunc(handler)))
         return;
 
-    node->addChangeListener(new FGNasalListener(handler, this, gcSave(handler)));
+    gcSave(handler);
+    node->addChangeListener(new FGNasalListener(handler, this));
 }
 
 // functions providing access to the NasalDisplay - used to display text directly on the screen
diff --git a/src/Scripting/NasalSys.hxx b/src/Scripting/NasalSys.hxx
index 1a1423bc6..41e3d96ef 100644
--- a/src/Scripting/NasalSys.hxx
+++ b/src/Scripting/NasalSys.hxx
@@ -112,20 +112,21 @@ private:
 
 class FGNasalListener : public SGPropertyChangeListener {
 public:
-    FGNasalListener(naRef handler, FGNasalSys* nasal, int gcKey)
-            : _handler(handler), _gcKey(gcKey), _nas(nasal) {}
+    FGNasalListener(naRef handler, FGNasalSys* nasal)
+            : _handler(handler), _nas(nasal) {}
 
     void valueChanged(SGPropertyNode* node) {
         _nas->_cmdArg = node;
-        naCall(_nas->_context, _handler, 0, 0, naNil(), naNil());
-        if(naGetError(_nas->_context))
+        naContext subc = naNewContext();
+        naCall(subc, _handler, 0, 0, naNil(), naNil());
+        if(naGetError(subc))
             _nas->logError();
+        naFreeContext(subc);
     }
 
 private:
     friend class FGNasalSys;
     naRef _handler;
-    int _gcKey;
     FGNasalSys* _nas;
 };