Fix problem found by Andrew Wason <aw@softcom.com>:

Subject:
        null arguments
   Date:
        Wed, 04 Aug 1999 13:22:35 -0400
   From:
        Andrew Wason <aw@softcom.com>
     To:
        norris@netscape.com
    CC:
        Howard Lin <howard@softcom.com>




When I try to pass a null argument to an interface implemented in JS, I get:

js: Cannot convert null to an object.
js: uncaught JavaScript exception:
org.mozilla.javascript.EvaluatorException: Cannot convert null to an object.


var b = new Packages.javax.swing.border.Border() {
        getBorderInsets : function(c) {
                return new Insets(0,0,0,0);
        }
};
b.getBorderInsets(null);


Here is the stack trace where the exception is happening:

java.lang.reflect.InvocationTargetException:
org.mozilla.javascript.EvaluatorException: Cannot convert null to an object.
         at
org.mozilla.javascript.tools.ToolErrorReporter.runtimeError(ToolErrorReporte
r.java:106)
         at org.mozilla.javascript.Context.reportRuntimeError(Context.java:484)
         at org.mozilla.javascript.Context.reportRuntimeError(Context.java:500)
         at
org.mozilla.javascript.ScriptRuntime.toObject(ScriptRuntime.java:529)
         at org.mozilla.javascript.Context.toObject(Context.java:1107)
         at adapter0.getBorderInsets(<adapter>)
         at java.lang.reflect.Method.invoke(Native Method)
         at
org.mozilla.javascript.NativeJavaMethod.call(NativeJavaMethod.java,
Compiled Code)
         at org.mozilla.javascript.ScriptRuntime.call(ScriptRuntime.java:1256)
         at org.mozilla.javascript.Interpreter.interpret(Interpreter.java,
Compiled Code)
         at
org.mozilla.javascript.InterpretedScript.call(InterpretedScript.java:49)
         at
org.mozilla.javascript.InterpretedScript.exec(InterpretedScript.java:37)
         at org.mozilla.javascript.Context.evaluateReader(Context.java:691)
         at
org.mozilla.javascript.tools.shell.Main.processSource(Main.java, Compiled Code)
         at org.mozilla.javascript.tools.shell.Main.main(Main.java:146)


Context.toObject does not allow wrapping nulls.
JavaAdapter.generateOverride should generate bytecode to check if an
argument is null and if it is not call Context.toObject.

I'll take a look at fixing this after the other JavaAdapter patches get
checked in so we don't get out of sync.

Andrew
--
Andrew Wason
SoftCom, Inc.
aw@softcom.com

js/rhino/org/mozilla/javascript/Context.java

@@ -1110,6 +1110,8 @@ public final class Context {
     public static Scriptable toObject(Object value, Scriptable scope, 
                                       Class staticType) 
     {
+        if (value == null && staticType != null)
+            return null;
         return ScriptRuntime.toObject(scope, value, staticType);
     }
 

js/rhino/src/org/mozilla/javascript/Context.java

@@ -1110,6 +1110,8 @@ public final class Context {
     public static Scriptable toObject(Object value, Scriptable scope, 
                                       Class staticType) 
     {
+        if (value == null && staticType != null)
+            return null;
         return ScriptRuntime.toObject(scope, value, staticType);
     }