1 files changed, 116 insertions, 0 deletions
diff --git a/js/xpconnect/wrappers/WaiveXrayWrapper.cpp b/js/xpconnect/wrappers/WaiveXrayWrapper.cpp
new file mode 100644
index 0000000000..9a4a24d8d7
--- /dev/null
+++ b/js/xpconnect/wrappers/WaiveXrayWrapper.cpp
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WaiveXrayWrapper.h"
+#include "WrapperFactory.h"
+#include "jsapi.h"
+
+using namespace JS;
+
+namespace xpc {
+
+static bool WaiveAccessors(JSContext* cx,
+                           MutableHandle<PropertyDescriptor> desc) {
+  if (desc.hasGetterObject() && desc.getterObject()) {
+    RootedValue v(cx, JS::ObjectValue(*desc.getterObject()));
+    if (!WrapperFactory::WaiveXrayAndWrap(cx, &v)) {
+      return false;
+    }
+    desc.setGetterObject(&v.toObject());
+  }
+
+  if (desc.hasSetterObject() && desc.setterObject()) {
+    RootedValue v(cx, JS::ObjectValue(*desc.setterObject()));
+    if (!WrapperFactory::WaiveXrayAndWrap(cx, &v)) {
+      return false;
+    }
+    desc.setSetterObject(&v.toObject());
+  }
+  return true;
+}
+
+bool WaiveXrayWrapper::getOwnPropertyDescriptor(
+    JSContext* cx, HandleObject wrapper, HandleId id,
+    MutableHandle<PropertyDescriptor> desc) const {
+  return CrossCompartmentWrapper::getOwnPropertyDescriptor(cx, wrapper, id,
+                                                           desc) &&
+         WrapperFactory::WaiveXrayAndWrap(cx, desc.value()) &&
+         WaiveAccessors(cx, desc);
+}
+
+bool WaiveXrayWrapper::get(JSContext* cx, HandleObject wrapper,
+                           HandleValue receiver, HandleId id,
+                           MutableHandleValue vp) const {
+  return CrossCompartmentWrapper::get(cx, wrapper, receiver, id, vp) &&
+         WrapperFactory::WaiveXrayAndWrap(cx, vp);
+}
+
+bool WaiveXrayWrapper::call(JSContext* cx, HandleObject wrapper,
+                            const JS::CallArgs& args) const {
+  return CrossCompartmentWrapper::call(cx, wrapper, args) &&
+         WrapperFactory::WaiveXrayAndWrap(cx, args.rval());
+}
+
+bool WaiveXrayWrapper::construct(JSContext* cx, HandleObject wrapper,
+                                 const JS::CallArgs& args) const {
+  return CrossCompartmentWrapper::construct(cx, wrapper, args) &&
+         WrapperFactory::WaiveXrayAndWrap(cx, args.rval());
+}
+
+// NB: This is important as the other side of a handshake with FieldGetter. See
+// nsXBLProtoImplField.cpp.
+bool WaiveXrayWrapper::nativeCall(JSContext* cx, JS::IsAcceptableThis test,
+                                  JS::NativeImpl impl,
+                                  const JS::CallArgs& args) const {
+  return CrossCompartmentWrapper::nativeCall(cx, test, impl, args) &&
+         WrapperFactory::WaiveXrayAndWrap(cx, args.rval());
+}
+
+bool WaiveXrayWrapper::hasInstance(JSContext* cx, HandleObject wrapper,
+                                   MutableHandleValue v, bool* bp) const {
+  if (v.isObject() && WrapperFactory::IsXrayWrapper(&v.toObject())) {
+    // If |v| is a XrayWrapper and in the same compartment as the value
+    // wrapped by |wrapper|, then the Xrays of |v| would be waived upon
+    // calling CrossCompartmentWrapper::hasInstance. This may trigger
+    // getters and proxy traps of unwrapped |v|. To prevent that from
+    // happening, we exit early.
+
+    // |wrapper| is the right operand of "instanceof", and must either be
+    // a function or an object with a @@hasInstance method. We are not going
+    // to call @@hasInstance, so only check whether it is a function.
+    // This check is here for consistency with usual "instanceof" behavior,
+    // which throws if the right operand is not a function. Without this
+    // check, the "instanceof" operator would return false and potentially
+    // hide errors in the code that uses the "instanceof" operator.
+    if (!JS::IsCallable(wrapper)) {
+      RootedValue wrapperv(cx, JS::ObjectValue(*wrapper));
+      js::ReportIsNotFunction(cx, wrapperv);
+      return false;
+    }
+
+    *bp = false;
+    return true;
+  }
+
+  // Both |wrapper| and |v| have no Xrays here.
+  return CrossCompartmentWrapper::hasInstance(cx, wrapper, v, bp);
+}
+
+bool WaiveXrayWrapper::getPrototype(JSContext* cx, HandleObject wrapper,
+                                    MutableHandleObject protop) const {
+  return CrossCompartmentWrapper::getPrototype(cx, wrapper, protop) &&
+         (!protop || WrapperFactory::WaiveXrayAndWrap(cx, protop));
+}
+
+bool WaiveXrayWrapper::getPrototypeIfOrdinary(
+    JSContext* cx, HandleObject wrapper, bool* isOrdinary,
+    MutableHandleObject protop) const {
+  return CrossCompartmentWrapper::getPrototypeIfOrdinary(cx, wrapper,
+                                                         isOrdinary, protop) &&
+         (!protop || WrapperFactory::WaiveXrayAndWrap(cx, protop));
+}
+
+}  // namespace xpc