Bug 1186213 - Add an API to deep-freeze the result of Cu.cloneInto. r=gkrizsanits

js/xpconnect/src/ExportHelpers.cpp

@@ -271,7 +271,17 @@ StackScopedClone(JSContext* cx, StackScopedCloneOptions& options,
     }
 
     // Now recreate the clones in the target compartment.
-    return buffer.read(cx, val, &gStackScopedCloneCallbacks, &data);
+    if (!buffer.read(cx, val, &gStackScopedCloneCallbacks, &data))
+        return false;
+
+    // Deep-freeze if requested.
+    if (options.deepFreeze && val.isObject()) {
+        RootedObject obj(cx, &val.toObject());
+        if (!JS_DeepFreezeObject(cx, obj))
+            return false;
+    }
+
+    return true;
 }
 
 // Note - This function mirrors the logic of CheckPassToChrome in

js/xpconnect/src/xpcprivate.h

@@ -3567,11 +3567,13 @@ public:
         : OptionsBase(cx, options)
         , wrapReflectors(false)
         , cloneFunctions(false)
+        , deepFreeze(false)
     { }
 
     virtual bool Parse() {
         return ParseBoolean("wrapReflectors", &wrapReflectors) &&
-               ParseBoolean("cloneFunctions", &cloneFunctions);
+               ParseBoolean("cloneFunctions", &cloneFunctions) &&
+               ParseBoolean("deepFreeze", &deepFreeze);
     }
 
     // When a reflector is encountered, wrap it rather than aborting the clone.
@@ -3580,6 +3582,9 @@ public:
     // When a function is encountered, clone it (exportFunction-style) rather than
     // aborting the clone.
     bool cloneFunctions;
+
+    // If true, the resulting object is deep-frozen after being cloned.
+    bool deepFreeze;
 };
 
 JSObject*

js/xpconnect/tests/unit/test_deepFreezeClone.js

@@ -0,0 +1,33 @@
+const Cu = Components.utils;
+
+function checkThrows(f, rgxp) { try { f(); do_check_false(); } catch (e) { do_check_true(rgxp.test(e)); } }
+
+var o = { foo: 42, bar : { tick: 'tock' } };
+function checkClone(clone, frozen) {
+  var waived = Cu.waiveXrays(clone);
+  function touchFoo() { "use strict"; waived.foo = 12; do_check_eq(waived.foo, 12); }
+  function touchBar() { "use strict"; waived.bar.tick = 'tack'; do_check_eq(waived.bar.tick, 'tack'); }
+  function addProp() { "use strict"; waived.newProp = 100; do_check_eq(waived.newProp, 100); }
+  if (!frozen) {
+    touchFoo();
+    touchBar();
+    addProp();
+  } else {
+    checkThrows(touchFoo, /read-only/);
+    checkThrows(touchBar, /read-only/);
+    checkThrows(addProp, /extensible/);
+  }
+
+  var desc = Object.getOwnPropertyDescriptor(waived, 'foo');
+  do_check_eq(desc.writable, !frozen);
+  do_check_eq(desc.configurable, !frozen);
+  desc = Object.getOwnPropertyDescriptor(waived.bar, 'tick');
+  do_check_eq(desc.writable, !frozen);
+  do_check_eq(desc.configurable, !frozen);
+}
+
+function run_test() {
+  var sb = new Cu.Sandbox(null);
+  checkClone(Cu.waiveXrays(Cu.cloneInto(o, sb)), false);
+  checkClone(Cu.cloneInto(o, sb, { deepFreeze: true }), true);
+}

js/xpconnect/tests/unit/xpcshell.ini

@@ -62,6 +62,7 @@ support-files =
 [test_bug1170311.js]
 [test_bug_442086.js]
 [test_callFunctionWithAsyncStack.js]
+[test_deepFreezeClone.js]
 [test_file.js]
 [test_blob.js]
 [test_blob2.js]