Implement basic tracer support. App properties to activate:

rhino.optlevel = -1
rhino.trace = true

src/helma/scripting/rhino/RhinoEngine.java

@@ -26,6 +26,7 @@ import helma.objectmodel.*;
 import helma.objectmodel.db.DbMapping;
 import helma.objectmodel.db.Relation;
 import helma.scripting.*;
+import helma.scripting.rhino.debug.Tracer;
 import helma.util.CacheMap;
 import helma.util.Updatable;
 import org.mozilla.javascript.*;
@@ -146,6 +147,12 @@ public class RhinoEngine implements ScriptingEngine {
         context.setCompileFunctionsWithDynamicScope(true);
         context.setWrapFactory(core.wrapper);
 
+        boolean trace = "true".equals(app.getProperty("rhino.trace"));
+
+        if (trace) {
+            context.setDebugger(new Tracer(getResponse()), null);
+        }
+
         int optLevel = 0;
 
         try {

src/helma/scripting/rhino/debug/Tracer.java

@@ -0,0 +1,112 @@
+/*
+ * Helma License Notice
+ *
+ * The contents of this file are subject to the Helma License
+ * Version 2.0 (the "License"). You may not use this file except in
+ * compliance with the License. A copy of the License is available at
+ * http://adele.helma.org/download/helma/license.txt
+ *
+ * Copyright 1998-2003 Helma Software. All Rights Reserved.
+ *
+ * $RCSfile$
+ * $Author$
+ * $Revision$
+ * $Date$
+ */
+
+package helma.scripting.rhino.debug;
+
+
+import org.mozilla.javascript.*;
+import org.mozilla.javascript.debug.*;
+import helma.framework.ResponseTrans;
+
+public class Tracer implements Debugger {
+
+    ResponseTrans res;
+
+    /**
+     *  Create a tracer that writes to this response object
+     */
+    public Tracer(ResponseTrans res) {
+        this.res = res;
+    }
+
+
+    /**
+     *  Implementws handleCompilationDone in interface org.mozilla.javascript.debug.Debugger
+     */
+    public void handleCompilationDone(Context cx, DebuggableScript script, String source) {
+        // res.debug("CompilationDone: "+toString(script));
+    }
+
+    /**
+     *  Implementws getFrame in interface org.mozilla.javascript.debug.Debugger
+     */
+    public DebugFrame getFrame(Context cx, DebuggableScript script) {
+        // res.debug("getFrame: "+toString(script));
+        if (script.isFunction()) {
+            return new TracerFrame(script);
+        }
+        return null;
+    }
+
+    static String toString(DebuggableScript script) {
+        if (script.isFunction()) {
+            return script.getSourceName()+": "+script.getFunctionName();
+        } else {
+            return script.getSourceName();
+        }
+    }
+
+class TracerFrame implements DebugFrame {
+
+    DebuggableScript script;
+
+    TracerFrame(DebuggableScript script) {
+        this.script = script;
+    }
+
+    /**
+     * Called when execution is ready to start bytecode interpretation
+     * for entered a particular function or script.
+     */
+    public void onEnter(Context cx, Scriptable activation,
+                            Scriptable thisObj, Object[] args) {
+        StringBuffer b = new StringBuffer("Trace: ");
+        b.append(Tracer.toString(script));
+        b.append("(");
+        for (int i=0; i<args.length; i++) {
+            b.append(args[i]);
+            if (i<args.length-1) {
+                b.append(", ");
+            }
+        }
+        b.append(")");
+        res.debug(b.toString());
+    }
+
+    /**
+     *  Called when thrown exception is handled by the function or script.
+     */
+    public void onExceptionThrown(Context cx, Throwable ex) {
+        res.debug("Exception Thrown: "+ex);
+    }
+
+    /**
+     *  Called when the function or script for this frame is about to return.
+     */
+    public void onExit(Context cx, boolean byThrow, Object resultOrException) {
+        // res.debug("Exit: "+Tracer.toString(script));
+    }
+
+    /**
+     *  Called when executed code reaches new line in the source.
+     */
+    public void onLineChange(Context cx, int lineNumber) {
+        // res.debug("LineChange: "+Tracer.toString(script));
+    }
+
+} // end of class TracerFrame
+} // end of class Tracer
+