[runtime] support new Proxy() instead of Proxy.create and install getPrototypeOf trap

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 827 matching lines @@
   Handle<FixedArray> elems(FixedArray::cast(object->elements()), isolate);
   if (elems->map() != isolate->heap()->fixed_cow_array_map()) return elems;
   Handle<FixedArray> writable_elems = isolate->factory()->CopyFixedArrayWithMap(
       elems, isolate->factory()->fixed_array_map());
   object->set_elements(*writable_elems);
   isolate->counters()->cow_arrays_converted()->Increment();
   return writable_elems;
 }
 
 
+// ES6 9.5.1
+// static
+MaybeHandle<Object> JSProxy::GetPrototype(Handle<JSProxy> proxy) {
+  Isolate* isolate = proxy->GetIsolate();
+  // 1. Let handler be the value of the [[ProxyHandler]] internal slot.
+  Handle<Object> raw_handler(proxy->handler(), isolate);
+  // 2. If handler is null, throw a TypeError exception.
+  // 3. Assert: Type(handler) is Object.
+  if (!raw_handler->IsSpecObject()) {
+    // TODO(cbruni): Throw correct error message.
+    THROW_NEW_ERROR(
+        isolate, NewTypeError(MessageTemplate::kProxyHandlerNonObject), Object);
+  }
+  Handle<JSReceiver> handler = Handle<JSReceiver>::cast(raw_handler);
+  // 4. Let target be the value of the [[ProxyTarget]] internal slot.
+  // TODO(cbruni): Change target type to JSReceiver by default.
+  Handle<JSReceiver> target(JSReceiver::cast(proxy->target()), isolate);
+  // 5. Let trap be ? GetMethod(handler, "getPrototypeOf").
+  Handle<Object> trap;
+  Handle<String> trap_name = isolate->factory()->getPrototypeOf_string();
+  ASSIGN_RETURN_ON_EXCEPTION(isolate, trap, GetMethod(handler, trap_name),
+                             Object);
+  // 6. If trap is undefined, then return target.[[GetPrototypeOf]]().
+  if (trap->IsUndefined()) {
+    return Object::GetPrototype(isolate, target);
+  }
+  // 7. Let handlerProto be ? Call(trap, handler, «target»).
+  Handle<Object> argv[] = {target};
+  Handle<Object> handler_proto;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate, handler_proto,
+      Execution::Call(isolate, trap, handler, arraysize(argv), argv), Object);
+  // 8. If Type(handlerProto) is neither Object nor Null, throw a TypeError.
+  if (!(handler_proto->IsSpecObject() || handler_proto->IsNull())) {
+    THROW_NEW_ERROR(isolate,
+                    NewTypeError(MessageTemplate::kProxyHandlerTrapMissing,
+                                 handler, trap_name),
+                    Object);
+  }
+  // 9. Let extensibleTarget be ? IsExtensible(target).
+  Maybe<bool> isExtensible = JSReceiver::IsExtensible(target);
+  if (isExtensible.IsNothing()) return MaybeHandle<Object>();
+  // 10. If extensibleTarget is true, return handlerProto.
+  if (isExtensible.FromJust()) return handler_proto;
+  // 11. Let targetProto be ? target.[[GetPrototypeOf]]().
+  Handle<Object> target_proto;
+  ASSIGN_RETURN_ON_EXCEPTION(isolate, handler_proto,
+                             Object::GetPrototype(isolate, target), Object);
+  // 12. If SameValue(handlerProto, targetProto) is false, throw a TypeError.
+  if (!handler_proto->SameValue(*target_proto)) {
+    THROW_NEW_ERROR(isolate,
+                    NewTypeError(MessageTemplate::kProxyHandlerTrapMissing,
+                                 handler, trap_name),
+                    Object);
+  }
+  // 13. Return handlerProto.
+  return handler_proto;
+}
+
+
 MaybeHandle<Object> JSProxy::GetPropertyWithHandler(Handle<JSProxy> proxy,
                                                     Handle<Object> receiver,
                                                     Handle<Name> name) {
   Isolate* isolate = proxy->GetIsolate();
 
   // TODO(rossberg): adjust once there is a story for symbols vs proxies.
   if (name->IsSymbol()) return isolate->factory()->undefined_value();
 
   Handle<Object> args[] = { receiver, name };
   return CallTrap(
@@ skipping 4697 matching lines @@
   proxy->set_hash(*hash);
   return hash;
 }
 
 
 Object* JSObject::GetIdentityHash() {
   DisallowHeapAllocation no_gc;
   Isolate* isolate = GetIsolate();
   if (IsJSGlobalProxy()) {
     return JSGlobalProxy::cast(this)->hash();
+  } else if (IsJSProxy()) {

[rossberg, 2015/11/12 17:04:39]

A JSObject can never be a JSProxy.

[Camillo Bruni, 2015/11/12 20:20:56]

indeed, wrong way around.

+    return JSProxy::cast(this)->GetIdentityHash();
   }
   Handle<Name> hash_code_symbol(isolate->heap()->hash_code_symbol());
   Handle<Object> stored_value =
       Object::GetPropertyOrElement(Handle<Object>(this, isolate),
                                    hash_code_symbol).ToHandleChecked();
   return stored_value->IsSmi() ? *stored_value
                                : isolate->heap()->undefined_value();
 }
 
 
 Handle<Smi> JSObject::GetOrCreateIdentityHash(Handle<JSObject> object) {
   if (object->IsJSGlobalProxy()) {
     return GetOrCreateIdentityHashHelper(Handle<JSGlobalProxy>::cast(object));
+  } else if (object->IsJSProxy()) {

[rossberg, 2015/11/12 17:04:39]

Saem here.

+    return JSProxy::GetOrCreateIdentityHash(Handle<JSProxy>::cast(object));
   }
 
   Isolate* isolate = object->GetIsolate();
 
   Handle<Object> maybe_hash(object->GetIdentityHash(), isolate);
   if (maybe_hash->IsSmi()) return Handle<Smi>::cast(maybe_hash);
 
   Handle<Smi> hash(GenerateIdentityHash(isolate), isolate);
   Handle<Name> hash_code_symbol(isolate->heap()->hash_code_symbol());
   JSObject::AddProperty(object, hash_code_symbol, hash, NONE);
@@ skipping 1284 matching lines @@
     RETURN_ON_EXCEPTION_VALUE(
         isolate,
         EnqueueChangeRecord(object, "preventExtensions", Handle<Name>(),
                             isolate->factory()->the_hole_value()),
         Nothing<bool>());
   }
   return Just(true);
 }
 
 
+// static
+Maybe<bool> JSReceiver::IsExtensible(Handle<JSReceiver> object) {
+  if (object->IsJSProxy()) {
+    // TODO(neis,cbruni): Redirect to the trap on JSProxy.
+    return Just(true);
+  }
+  return Just(JSObject::IsExtensible(Handle<JSObject>::cast(object)));
+}
+
+
 bool JSObject::IsExtensible(Handle<JSObject> object) {
   Isolate* isolate = object->GetIsolate();
   if (object->IsAccessCheckNeeded() &&
       !isolate->MayAccess(handle(isolate->context()), object)) {
     return true;
   }
   if (object->IsJSGlobalProxy()) {
     PrototypeIterator iter(isolate, *object);
     if (iter.IsAtEnd()) return false;
     DCHECK(iter.GetCurrent()->IsJSGlobalObject());
@@ skipping 1172 matching lines @@
   }
 
   return result;
 }
 
 
 Handle<Map> Map::CopyDropDescriptors(Handle<Map> map) {
   Handle<Map> result = RawCopy(map, map->instance_size());
 
   // Please note instance_type and instance_size are set when allocated.
-  result->SetInObjectProperties(map->GetInObjectProperties());
-  result->set_unused_property_fields(map->unused_property_fields());
-
+  if (map->IsJSObjectMap()) {
+    result->SetInObjectProperties(map->GetInObjectProperties());
+    result->set_unused_property_fields(map->unused_property_fields());
+  }
   result->ClearCodeCache(map->GetHeap());
   map->NotifyLeafMapLayoutChange();
   return result;
 }
 
 
 Handle<Map> Map::ShareDescriptor(Handle<Map> map,
                                  Handle<DescriptorArray> descriptors,
                                  Descriptor* descriptor) {
   // Sanity check. This path is only to be taken if the map owns its descriptor
@@ skipping 5847 matching lines @@
 
 
 Maybe<bool> JSObject::SetPrototype(Handle<JSObject> object,
                                    Handle<Object> value, bool from_javascript,
                                    ShouldThrow should_throw) {
   Isolate* isolate = object->GetIsolate();
 
   const bool observed = from_javascript && object->map()->is_observed();
   Handle<Object> old_value;
   if (observed) {
-    old_value = Object::GetPrototype(isolate, object);
+    ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, old_value,
+                                     Object::GetPrototype(isolate, object),
+                                     Nothing<bool>());
   }
 
   Maybe<bool> result =
       SetPrototypeUnobserved(object, value, from_javascript, should_throw);
   MAYBE_RETURN(result, Nothing<bool>());
 
   if (result.FromJust() && observed) {
-    Handle<Object> new_value = Object::GetPrototype(isolate, object);
+    Handle<Object> new_value;
+    ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, new_value,
+                                     Object::GetPrototype(isolate, object),
+                                     Nothing<bool>());
     if (!new_value->SameValue(*old_value)) {
       RETURN_ON_EXCEPTION_VALUE(
           isolate, JSObject::EnqueueChangeRecord(
                        object, "setPrototype",
                        isolate->factory()->proto_string(), old_value),
           Nothing<bool>());
     }
   }
 
   return result;
@@ skipping 3938 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8