Allow freezing of NativeJavaObject and subclasses

rhino/src/main/java/org/mozilla/javascript/AbstractEcmaObjectOperations.java

@@ -122,9 +122,15 @@ static boolean setIntegrityLevel(Context cx, Object o, INTEGRITY_LEVEL level) {
              7. both conditions under which false would be returned cannot occur here
              8. both conditions under which false would be returned cannot occur here
         */
+        // TODO check .preventExtensions() return value once implemented and act accordingly to spec
+
+        if (o instanceof NativeJavaObject) {
+            ((NativeJavaObject) o).freezeObject();
+            return true;
+        }
+
         ScriptableObject obj = ScriptableObject.ensureScriptableObject(o);
 
-        // TODO check .preventExtensions() return value once implemented and act accordingly to spec
         obj.preventExtensions();
 
         for (Object key : obj.getIds(true, true)) {

rhino/src/main/java/org/mozilla/javascript/NativeJavaArray.java

@@ -99,6 +99,9 @@ public void put(String id, Scriptable start, Object value) {
     @Override
     public void put(int index, Scriptable start, Object value) {
         if (0 <= index && index < length) {
+            if (super.checkFrozen(Integer.toString(index)) == FrozenCheckResult.SILENTLY_IGNORE)
+                return;
+
             Array.set(array, index, Context.jsToJava(value, cls));
         } else {
             throw Context.reportRuntimeErrorById(

rhino/src/main/java/org/mozilla/javascript/NativeJavaClass.java

@@ -94,6 +94,7 @@ public Object get(String name, Scriptable start) {
 
     @Override
     public void put(String name, Scriptable start, Object value) {
+        if (super.checkFrozen(name) == FrozenCheckResult.SILENTLY_IGNORE) return;
         members.put(this, name, javaObject, value, true);
     }
 

rhino/src/main/java/org/mozilla/javascript/NativeJavaList.java

@@ -124,6 +124,9 @@ public Object get(Symbol key, Scriptable start) {
     @Override
     public void put(int index, Scriptable start, Object value) {
         if (index >= 0) {
+            if (super.checkFrozen(Integer.toString(index)) == FrozenCheckResult.SILENTLY_IGNORE)
+                return;
+
             Object javaValue = Context.jsToJava(value, Object.class);
             if (index == list.size()) {
                 list.add(javaValue); // use "add" at the end of list.
@@ -139,6 +142,8 @@ public void put(int index, Scriptable start, Object value) {
     @Override
     public void put(String name, Scriptable start, Object value) {
         if (list != null && "length".equals(name)) {
+            if (super.checkFrozen(name) == FrozenCheckResult.SILENTLY_IGNORE) return;
+
             setLength(value);
             return;
         }

rhino/src/main/java/org/mozilla/javascript/NativeJavaMap.java

@@ -109,6 +109,7 @@ public Object get(Symbol key, Scriptable start) {
     public void put(String name, Scriptable start, Object value) {
         Context cx = Context.getCurrentContext();
         if (cx != null && cx.hasFeature(Context.FEATURE_ENABLE_JAVA_MAP_ACCESS)) {
+            if (super.checkFrozen(name) == FrozenCheckResult.SILENTLY_IGNORE) return;
             map.put(name, Context.jsToJava(value, Object.class));
         } else {
             super.put(name, start, value);
@@ -119,6 +120,8 @@ public void put(String name, Scriptable start, Object value) {
     public void put(int index, Scriptable start, Object value) {
         Context cx = Context.getContext();
         if (cx != null && cx.hasFeature(Context.FEATURE_ENABLE_JAVA_MAP_ACCESS)) {
+            if (super.checkFrozen(Integer.toString(index)) == FrozenCheckResult.SILENTLY_IGNORE)
+                return;
             map.put(Integer.valueOf(index), Context.jsToJava(value, Object.class));
         } else {
             super.put(index, start, value);

rhino/src/main/java/org/mozilla/javascript/NativeJavaObject.java

@@ -115,9 +115,13 @@ public void put(String name, Scriptable start, Object value) {
         // We could be asked to modify the value of a property in the
         // prototype. Since we can't add a property to a Java object,
         // we modify it in the prototype rather than copy it down.
-        if (prototype == null || members.has(name, false))
+        if (prototype == null || members.has(name, false)) {
+            if (checkFrozen(name) == FrozenCheckResult.SILENTLY_IGNORE) return;
+
             members.put(this, name, javaObject, value, false);
-        else prototype.put(name, prototype, value);
+        } else {
+            prototype.put(name, prototype, value);
+        }
     }
 
     @Override
@@ -127,6 +131,8 @@ public void put(Symbol symbol, Scriptable start, Object value) {
         // we modify it in the prototype rather than copy it down.
         String name = symbol.toString();
         if (prototype == null || members.has(name, false)) {
+            if (checkFrozen(symbol.toString()) == FrozenCheckResult.SILENTLY_IGNORE) return;
+
             members.put(this, name, javaObject, value, false);
         } else if (prototype instanceof SymbolScriptable) {
             ((SymbolScriptable) prototype).put(symbol, prototype, value);
@@ -249,6 +255,38 @@ public Object getDefaultValue(Class<?> hint) {
         return value;
     }
 
+    /**
+     * Freeze this object, preventing changes to the values of existing properties. It is already
+     * not possible to defined new properties on this class, so we do not need to distinguish like
+     * {@link ScriptableObject#isExtensible} and {@link ScriptableObject#isSealed}.
+     */
+    public void freezeObject() {
+        this.isFrozen = true;
+    }
+
+    /**
+     * Checks whether the object is frozen or not. Can either throw an exception (in strict mode) or
+     * return whether we should perform or silently ignore the assignment.
+     */
+    protected FrozenCheckResult checkFrozen(String id) {
+        if (isFrozen) {
+            // In strict mode, we throw an error. In non-strict mode, we silently ignore the
+            // assignment
+            if (Context.isCurrentContextStrict()) {
+                String msg = "Assignment to \"" + id + "\" on frozen object in strict mode";
+                throw ScriptRuntime.constructError("ReferenceError", msg);
+            } else return FrozenCheckResult.SILENTLY_IGNORE;
+        }
+
+        // Go ahead!
+        return FrozenCheckResult.PERFORM_ASSIGNMENT;
+    }
+
+    protected enum FrozenCheckResult {
+        SILENTLY_IGNORE,
+        PERFORM_ASSIGNMENT,
+    }
+
     /**
      * Determine whether we can/should convert between the given type and the desired one. This
      * should be superceded by a conversion-cost calculation function, but for now I'll hide behind
@@ -958,6 +996,7 @@ protected String getTag() {
     protected Scriptable parent;
 
     protected transient Object javaObject;
+    protected transient boolean isFrozen = false;
 
     protected transient Class<?> staticType;
     protected transient JavaMembers members;

rhino/src/main/java/org/mozilla/javascript/NativeObject.java

@@ -633,7 +633,8 @@ public Object execIdCall(
                 {
                     Object arg = args.length < 1 ? Undefined.instance : args[0];
                     if (cx.getLanguageVersion() >= Context.VERSION_ES6
-                            && !(arg instanceof ScriptableObject)) {
+                            && !(arg instanceof ScriptableObject)
+                            && !(arg instanceof NativeJavaObject)) {
                         return arg;
                     }