1 files changed, 362 insertions, 0 deletions
diff --git a/dom/bindings/DOMJSProxyHandler.cpp b/dom/bindings/DOMJSProxyHandler.cpp
new file mode 100644
index 000000000..65e540bc1
--- /dev/null
+++ b/dom/bindings/DOMJSProxyHandler.cpp
@@ -0,0 +1,362 @@
+/* -*- 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 "mozilla/dom/DOMJSProxyHandler.h"
+#include "xpcpublic.h"
+#include "xpcprivate.h"
+#include "XPCWrapper.h"
+#include "WrapperFactory.h"
+#include "nsDOMClassInfo.h"
+#include "nsWrapperCacheInlines.h"
+#include "mozilla/dom/BindingUtils.h"
+
+#include "jsapi.h"
+
+using namespace JS;
+
+namespace mozilla {
+namespace dom {
+
+jsid s_length_id = JSID_VOID;
+
+bool
+DefineStaticJSVals(JSContext* cx)
+{
+  return AtomizeAndPinJSString(cx, s_length_id, "length");
+}
+
+const char DOMProxyHandler::family = 0;
+
+js::DOMProxyShadowsResult
+DOMProxyShadows(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id)
+{
+  JS::Rooted<JSObject*> expando(cx, DOMProxyHandler::GetExpandoObject(proxy));
+  JS::Value v = js::GetProxyExtra(proxy, JSPROXYSLOT_EXPANDO);
+  bool isOverrideBuiltins = !v.isObject() && !v.isUndefined();
+  if (expando) {
+    bool hasOwn;
+    if (!JS_AlreadyHasOwnPropertyById(cx, expando, id, &hasOwn))
+      return js::ShadowCheckFailed;
+
+    if (hasOwn) {
+      return isOverrideBuiltins ?
+        js::ShadowsViaIndirectExpando : js::ShadowsViaDirectExpando;
+    }
+  }
+
+  if (!isOverrideBuiltins) {
+    // Our expando, if any, didn't shadow, so we're not shadowing at all.
+    return js::DoesntShadow;
+  }
+
+  bool hasOwn;
+  if (!GetProxyHandler(proxy)->hasOwn(cx, proxy, id, &hasOwn))
+    return js::ShadowCheckFailed;
+
+  return hasOwn ? js::Shadows : js::DoesntShadowUnique;
+}
+
+// Store the information for the specialized ICs.
+struct SetDOMProxyInformation
+{
+  SetDOMProxyInformation() {
+    js::SetDOMProxyInformation((const void*) &DOMProxyHandler::family,
+                               JSPROXYSLOT_EXPANDO, DOMProxyShadows);
+  }
+};
+
+SetDOMProxyInformation gSetDOMProxyInformation;
+
+// static
+void
+DOMProxyHandler::ClearExternalRefsForWrapperRelease(JSObject* obj)
+{
+  MOZ_ASSERT(IsDOMProxy(obj), "expected a DOM proxy object");
+  JS::Value v = js::GetProxyExtra(obj, JSPROXYSLOT_EXPANDO);
+  if (v.isUndefined()) {
+    // No expando.
+    return;
+  }
+
+  // See EnsureExpandoObject for the work we're trying to undo here.
+
+  if (v.isObject()) {
+    // Drop us from the DOM expando hashtable.  Don't worry about clearing our
+    // slot reference to the expando; we're about to die anyway.
+    xpc::ObjectScope(obj)->RemoveDOMExpandoObject(obj);
+    return;
+  }
+
+  // Prevent having a dangling pointer to our expando from the
+  // ExpandoAndGeneration.
+  js::ExpandoAndGeneration* expandoAndGeneration =
+    static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
+  expandoAndGeneration->expando = UndefinedValue();
+}
+
+// static
+JSObject*
+DOMProxyHandler::GetAndClearExpandoObject(JSObject* obj)
+{
+  MOZ_ASSERT(IsDOMProxy(obj), "expected a DOM proxy object");
+  JS::Value v = js::GetProxyExtra(obj, JSPROXYSLOT_EXPANDO);
+  if (v.isUndefined()) {
+    return nullptr;
+  }
+
+  if (v.isObject()) {
+    js::SetProxyExtra(obj, JSPROXYSLOT_EXPANDO, UndefinedValue());
+    xpc::ObjectScope(obj)->RemoveDOMExpandoObject(obj);
+  } else {
+    js::ExpandoAndGeneration* expandoAndGeneration =
+      static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
+    v = expandoAndGeneration->expando;
+    if (v.isUndefined()) {
+      return nullptr;
+    }
+    // We have to expose v to active JS here.  The reason for that is that we
+    // might be in the middle of a GC right now.  If our proxy hasn't been
+    // traced yet, when it _does_ get traced it won't trace the expando, since
+    // we're breaking that link.  But the Rooted we're presumably being placed
+    // into is also not going to trace us, because Rooted marking is done at
+    // the very beginning of the GC.  In that situation, we need to manually
+    // mark the expando as live here.  JS::ExposeValueToActiveJS will do just
+    // that for us.
+    //
+    // We don't need to do this in the non-expandoAndGeneration case, because
+    // in that case our value is stored in a slot and slots will already mark
+    // the old thing live when the value in the slot changes.
+    JS::ExposeValueToActiveJS(v);
+    expandoAndGeneration->expando = UndefinedValue();
+  }
+
+
+  return &v.toObject();
+}
+
+// static
+JSObject*
+DOMProxyHandler::EnsureExpandoObject(JSContext* cx, JS::Handle<JSObject*> obj)
+{
+  NS_ASSERTION(IsDOMProxy(obj), "expected a DOM proxy object");
+  JS::Value v = js::GetProxyExtra(obj, JSPROXYSLOT_EXPANDO);
+  if (v.isObject()) {
+    return &v.toObject();
+  }
+
+  js::ExpandoAndGeneration* expandoAndGeneration;
+  if (!v.isUndefined()) {
+    expandoAndGeneration = static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
+    if (expandoAndGeneration->expando.isObject()) {
+      return &expandoAndGeneration->expando.toObject();
+    }
+  } else {
+    expandoAndGeneration = nullptr;
+  }
+
+  JS::Rooted<JSObject*> expando(cx,
+    JS_NewObjectWithGivenProto(cx, nullptr, nullptr));
+  if (!expando) {
+    return nullptr;
+  }
+
+  nsISupports* native = UnwrapDOMObject<nsISupports>(obj);
+  nsWrapperCache* cache;
+  CallQueryInterface(native, &cache);
+  if (expandoAndGeneration) {
+    cache->PreserveWrapper(native);
+    expandoAndGeneration->expando.setObject(*expando);
+
+    return expando;
+  }
+
+  if (!xpc::ObjectScope(obj)->RegisterDOMExpandoObject(obj)) {
+    return nullptr;
+  }
+
+  cache->SetPreservingWrapper(true);
+  js::SetProxyExtra(obj, JSPROXYSLOT_EXPANDO, ObjectValue(*expando));
+
+  return expando;
+}
+
+bool
+DOMProxyHandler::preventExtensions(JSContext* cx, JS::Handle<JSObject*> proxy,
+                                   JS::ObjectOpResult& result) const
+{
+  // always extensible per WebIDL
+  return result.failCantPreventExtensions();
+}
+
+bool
+DOMProxyHandler::isExtensible(JSContext *cx, JS::Handle<JSObject*> proxy, bool *extensible) const
+{
+  *extensible = true;
+  return true;
+}
+
+bool
+BaseDOMProxyHandler::getOwnPropertyDescriptor(JSContext* cx,
+                                              JS::Handle<JSObject*> proxy,
+                                              JS::Handle<jsid> id,
+                                              MutableHandle<PropertyDescriptor> desc) const
+{
+  return getOwnPropDescriptor(cx, proxy, id, /* ignoreNamedProps = */ false,
+                              desc);
+}
+
+bool
+DOMProxyHandler::defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+                                Handle<PropertyDescriptor> desc,
+                                JS::ObjectOpResult &result, bool *defined) const
+{
+  if (desc.hasGetterObject() && desc.setter() == JS_StrictPropertyStub) {
+    return result.failGetterOnly();
+  }
+
+  if (xpc::WrapperFactory::IsXrayWrapper(proxy)) {
+    return result.succeed();
+  }
+
+  JS::Rooted<JSObject*> expando(cx, EnsureExpandoObject(cx, proxy));
+  if (!expando) {
+    return false;
+  }
+
+  if (!JS_DefinePropertyById(cx, expando, id, desc, result)) {
+    return false;
+  }
+  *defined = true;
+  return true;
+}
+
+bool
+DOMProxyHandler::set(JSContext *cx, Handle<JSObject*> proxy, Handle<jsid> id,
+                     Handle<JS::Value> v, Handle<JS::Value> receiver,
+                     ObjectOpResult &result) const
+{
+  MOZ_ASSERT(!xpc::WrapperFactory::IsXrayWrapper(proxy),
+             "Should not have a XrayWrapper here");
+  bool done;
+  if (!setCustom(cx, proxy, id, v, &done)) {
+    return false;
+  }
+  if (done) {
+    return result.succeed();
+  }
+
+  // Make sure to ignore our named properties when checking for own
+  // property descriptors for a set.
+  JS::Rooted<PropertyDescriptor> ownDesc(cx);
+  if (!getOwnPropDescriptor(cx, proxy, id, /* ignoreNamedProps = */ true,
+                            &ownDesc)) {
+    return false;
+  }
+  return js::SetPropertyIgnoringNamedGetter(cx, proxy, id, v, receiver, ownDesc, result);
+}
+
+bool
+DOMProxyHandler::delete_(JSContext* cx, JS::Handle<JSObject*> proxy,
+                         JS::Handle<jsid> id, JS::ObjectOpResult &result) const
+{
+  JS::Rooted<JSObject*> expando(cx);
+  if (!xpc::WrapperFactory::IsXrayWrapper(proxy) && (expando = GetExpandoObject(proxy))) {
+    return JS_DeletePropertyById(cx, expando, id, result);
+  }
+
+  return result.succeed();
+}
+
+bool
+BaseDOMProxyHandler::watch(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+                           JS::Handle<JSObject*> callable) const
+{
+  return js::WatchGuts(cx, proxy, id, callable);
+}
+
+bool
+BaseDOMProxyHandler::unwatch(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id) const
+{
+  return js::UnwatchGuts(cx, proxy, id);
+}
+
+bool
+BaseDOMProxyHandler::ownPropertyKeys(JSContext* cx,
+                                     JS::Handle<JSObject*> proxy,
+                                     JS::AutoIdVector& props) const
+{
+  return ownPropNames(cx, proxy, JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS, props);
+}
+
+bool
+BaseDOMProxyHandler::getPrototypeIfOrdinary(JSContext* cx, JS::Handle<JSObject*> proxy,
+                                            bool* isOrdinary,
+                                            JS::MutableHandle<JSObject*> proto) const
+{
+  *isOrdinary = true;
+  proto.set(GetStaticPrototype(proxy));
+  return true;
+}
+
+bool
+BaseDOMProxyHandler::getOwnEnumerablePropertyKeys(JSContext* cx,
+                                                  JS::Handle<JSObject*> proxy,
+                                                  JS::AutoIdVector& props) const
+{
+  return ownPropNames(cx, proxy, JSITER_OWNONLY, props);
+}
+
+bool
+DOMProxyHandler::setCustom(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
+                           JS::Handle<JS::Value> v, bool *done) const
+{
+  *done = false;
+  return true;
+}
+
+//static
+JSObject *
+DOMProxyHandler::GetExpandoObject(JSObject *obj)
+{
+  MOZ_ASSERT(IsDOMProxy(obj), "expected a DOM proxy object");
+  JS::Value v = js::GetProxyExtra(obj, JSPROXYSLOT_EXPANDO);
+  if (v.isObject()) {
+    return &v.toObject();
+  }
+
+  if (v.isUndefined()) {
+    return nullptr;
+  }
+
+  js::ExpandoAndGeneration* expandoAndGeneration =
+    static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
+  v = expandoAndGeneration->expando;
+  return v.isUndefined() ? nullptr : &v.toObject();
+}
+
+void
+ShadowingDOMProxyHandler::trace(JSTracer* trc, JSObject* proxy) const
+{
+  DOMProxyHandler::trace(trc, proxy);
+
+  MOZ_ASSERT(IsDOMProxy(proxy), "expected a DOM proxy object");
+  JS::Value v = js::GetProxyExtra(proxy, JSPROXYSLOT_EXPANDO);
+  MOZ_ASSERT(!v.isObject(), "Should not have expando object directly!");
+
+  if (v.isUndefined()) {
+    // This can happen if we GC while creating our object, before we get a
+    // chance to set up its JSPROXYSLOT_EXPANDO slot.
+    return;
+  }
+
+  js::ExpandoAndGeneration* expandoAndGeneration =
+    static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
+  JS::TraceEdge(trc, &expandoAndGeneration->expando,
+                "Shadowing DOM proxy expando");
+}
+
+} // namespace dom
+} // namespace mozilla