[proxies] Update Object.defineProperty/ies for JSProxies

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 4647 matching lines @@
     THROW_NEW_ERROR(
         isolate,
         NewTypeError(MessageTemplate::kProxyHandlerDeleteFailed, handler),
         Object);
   }
   return isolate->factory()->ToBoolean(result_bool);
 }
 
 
 Maybe<PropertyAttributes> JSProxy::GetPropertyAttributesWithHandler(
-    Handle<JSProxy> proxy, Handle<Object> receiver, Handle<Name> name) {
-  Isolate* isolate = proxy->GetIsolate();
+    LookupIterator* it) {
+  Isolate* isolate = it->isolate();
   HandleScope scope(isolate);
-
-  // TODO(rossberg): adjust once there is a story for symbols vs proxies.
-  if (name->IsSymbol()) return Just(ABSENT);
-
-  Handle<Object> args[] = { name };
-  Handle<Object> result;
-  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
-      isolate, result, proxy->CallTrap(proxy, "getPropertyDescriptor",
-                                       Handle<Object>(), arraysize(args), args),
-      Nothing<PropertyAttributes>());
-
-  if (result->IsUndefined()) return Just(ABSENT);
-
-  Handle<Object> argv[] = { result };
-  Handle<Object> desc;
-  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
-      isolate, desc,
-      Execution::Call(isolate, isolate->to_complete_property_descriptor(),
-                      result, arraysize(argv), argv),
-      Nothing<PropertyAttributes>());
-
-  // Convert result to PropertyAttributes.
-  Handle<String> enum_n = isolate->factory()->InternalizeOneByteString(
-      STATIC_CHAR_VECTOR("enumerable_"));
-  Handle<Object> enumerable;
-  ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, enumerable,
-                                   Object::GetProperty(desc, enum_n),
-                                   Nothing<PropertyAttributes>());
-  Handle<String> conf_n = isolate->factory()->InternalizeOneByteString(
-      STATIC_CHAR_VECTOR("configurable_"));
-  Handle<Object> configurable;
-  ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, configurable,
-                                   Object::GetProperty(desc, conf_n),
-                                   Nothing<PropertyAttributes>());
-  Handle<String> writ_n = isolate->factory()->InternalizeOneByteString(
-      STATIC_CHAR_VECTOR("writable_"));
-  Handle<Object> writable;
-  ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, writable,
-                                   Object::GetProperty(desc, writ_n),
-                                   Nothing<PropertyAttributes>());
-  if (!writable->BooleanValue()) {
-    Handle<String> set_n = isolate->factory()->InternalizeOneByteString(
-        STATIC_CHAR_VECTOR("set_"));
-    Handle<Object> setter;
-    ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, setter,
-                                     Object::GetProperty(desc, set_n),
-                                     Nothing<PropertyAttributes>());
-    writable = isolate->factory()->ToBoolean(!setter->IsUndefined());
-  }
-
-  if (configurable->IsFalse()) {
-    Handle<Object> handler(proxy->handler(), isolate);
-    Handle<String> trap = isolate->factory()->InternalizeOneByteString(
-        STATIC_CHAR_VECTOR("getPropertyDescriptor"));
-    Handle<Object> error = isolate->factory()->NewTypeError(
-        MessageTemplate::kProxyPropNotConfigurable, handler, name, trap);
-    isolate->Throw(*error);
-    return Nothing<PropertyAttributes>();
-  }
-
-  int attributes = NONE;
-  if (!enumerable->BooleanValue()) attributes |= DONT_ENUM;
-  if (!configurable->BooleanValue()) attributes |= DONT_DELETE;
-  if (!writable->BooleanValue()) attributes |= READ_ONLY;
-  return Just(static_cast<PropertyAttributes>(attributes));
+  PropertyDescriptor desc;
+  bool found = JSProxy::GetOwnPropertyDescriptor(it, &desc);
+  if (isolate->has_pending_exception()) return Nothing<PropertyAttributes>();
+  if (!found) return Just(ABSENT);
+  return Just(desc.ToAttributes());
 }
 
 
 MaybeHandle<Object> JSProxy::CallTrap(Handle<JSProxy> proxy,
                                       const char* name,
                                       Handle<Object> derived,
                                       int argc,
                                       Handle<Object> argv[]) {
   Isolate* isolate = proxy->GetIsolate();
   Handle<Object> handler(proxy->handler(), isolate);
@@ skipping 362 matching lines @@
 
 
 Maybe<PropertyAttributes> JSReceiver::GetPropertyAttributes(
     LookupIterator* it) {
   for (; it->IsFound(); it->Next()) {
     switch (it->state()) {
       case LookupIterator::NOT_FOUND:
       case LookupIterator::TRANSITION:
         UNREACHABLE();
       case LookupIterator::JSPROXY:
-        return JSProxy::GetPropertyAttributesWithHandler(
-            it->GetHolder<JSProxy>(), it->GetReceiver(), it->GetName());
+        return JSProxy::GetPropertyAttributesWithHandler(it);
       case LookupIterator::INTERCEPTOR: {
         Maybe<PropertyAttributes> result =
             JSObject::GetPropertyAttributesWithInterceptor(it);
         if (!result.IsJust()) return result;
         if (result.FromJust() != ABSENT) return result;
         break;
       }
       case LookupIterator::ACCESS_CHECK:
         if (it->HasAccess()) break;
         return JSObject::GetPropertyAttributesWithFailedAccessCheck(it);
@@ skipping 877 matching lines @@
   return Object::ToString(isolate, key);
 }
 
 
 // ES6 19.1.2.4
 // static
 Object* JSReceiver::DefineProperty(Isolate* isolate, Handle<Object> object,
                                    Handle<Object> key,
                                    Handle<Object> attributes) {
   // 1. If Type(O) is not Object, throw a TypeError exception.
-  // TODO(jkummerow): Implement Proxy support, change to "IsSpecObject".
-  if (!object->IsJSObject()) {
+  if (!object->IsSpecObject()) {
     Handle<String> fun_name =
         isolate->factory()->InternalizeUtf8String("Object.defineProperty");
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewTypeError(MessageTemplate::kCalledOnNonObject, fun_name));
   }
   // 2. Let key be ToPropertyKey(P).
   // 3. ReturnIfAbrupt(key).
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, key, ToPropertyKey(isolate, key));
   // 4. Let desc be ToPropertyDescriptor(Attributes).
   // 5. ReturnIfAbrupt(desc).
   PropertyDescriptor desc;
   if (!PropertyDescriptor::ToPropertyDescriptor(isolate, attributes, &desc)) {
     return isolate->heap()->exception();
   }
   // 6. Let success be DefinePropertyOrThrow(O,key, desc).
-  bool success = DefineOwnProperty(isolate, Handle<JSObject>::cast(object), key,
-                                   &desc, THROW_ON_ERROR);
+  bool success = DefineOwnProperty(isolate, Handle<JSReceiver>::cast(object),
+                                   key, &desc, THROW_ON_ERROR);
   // 7. ReturnIfAbrupt(success).
   if (isolate->has_pending_exception()) return isolate->heap()->exception();
   CHECK(success == true);
   // 8. Return O.
   return *object;
 }
 
 
 // ES6 19.1.2.3.1
 // static
 Object* JSReceiver::DefineProperties(Isolate* isolate, Handle<Object> object,
                                      Handle<Object> properties) {
   // 1. If Type(O) is not Object, throw a TypeError exception.
-  // TODO(jkummerow): Implement Proxy support, change to "IsSpecObject".
-  if (!object->IsJSObject()) {
+  if (!object->IsSpecObject()) {
     Handle<String> fun_name =
         isolate->factory()->InternalizeUtf8String("Object.defineProperties");
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewTypeError(MessageTemplate::kCalledOnNonObject, fun_name));
   }
   // 2. Let props be ToObject(Properties).
   // 3. ReturnIfAbrupt(props).
   Handle<JSReceiver> props;
   if (!Object::ToObject(isolate, properties).ToHandle(&props)) {
     THROW_NEW_ERROR_RETURN_FAILURE(
@@ skipping 10 matching lines @@
   std::vector<PropertyDescriptor> descriptors(capacity);
   // 7. Repeat for each element nextKey of keys in List order,
   for (int i = 0; i < keys->length(); ++i) {
     Handle<Object> next_key(keys->get(i), isolate);
     // 7a. Let propDesc be props.[[GetOwnProperty]](nextKey).
     // 7b. ReturnIfAbrupt(propDesc).
     bool success = false;
     LookupIterator it = LookupIterator::PropertyOrElement(
         isolate, props, next_key, &success, LookupIterator::HIDDEN);
     DCHECK(success);
-    // TODO(jkummerow): Support JSProxies. Make sure we call the correct
-    // getOwnPropertyDescriptor trap, and convert the result object to a
-    // PropertyDescriptor.
-    Maybe<PropertyAttributes> maybe = JSObject::GetPropertyAttributes(&it);
+    Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
     if (!maybe.IsJust()) return isolate->heap()->exception();
     PropertyAttributes attrs = maybe.FromJust();
     // 7c. If propDesc is not undefined and propDesc.[[Enumerable]] is true:
     if (attrs == ABSENT) continue;
     // GetKeys() only returns enumerable keys.
     DCHECK((attrs & DONT_ENUM) == 0);
     // 7c i. Let descObj be Get(props, nextKey).
     // 7c ii. ReturnIfAbrupt(descObj).
     Handle<Object> desc_obj;
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, desc_obj,
-                                       JSObject::GetProperty(&it));
+                                       Object::GetProperty(&it));
     // 7c iii. Let desc be ToPropertyDescriptor(descObj).
     success = PropertyDescriptor::ToPropertyDescriptor(isolate, desc_obj,
                                                        &descriptors[i]);
     // 7c iv. ReturnIfAbrupt(desc).
     if (!success) return isolate->heap()->exception();
     // 7c v. Append the pair (a two element List) consisting of nextKey and
     //       desc to the end of descriptors.
     descriptors[i].set_name(next_key);
   }
   // 8. For each pair from descriptors in list order,
   for (size_t i = 0; i < descriptors.size(); ++i) {
     PropertyDescriptor* desc = &descriptors[i];
     // 8a. Let P be the first element of pair.
     // 8b. Let desc be the second element of pair.
     // 8c. Let status be DefinePropertyOrThrow(O, P, desc).
-    bool status = DefineOwnProperty(isolate, Handle<JSObject>::cast(object),
+    bool status = DefineOwnProperty(isolate, Handle<JSReceiver>::cast(object),
                                     desc->name(), desc, THROW_ON_ERROR);
     // 8d. ReturnIfAbrupt(status).
     if (isolate->has_pending_exception()) return isolate->heap()->exception();
     CHECK(status == true);
   }
   // 9. Return o.
   return *object;
 }
 
 
 // static
 bool JSReceiver::DefineOwnProperty(Isolate* isolate, Handle<JSReceiver> object,
                                    Handle<Object> key, PropertyDescriptor* desc,
                                    ShouldThrow should_throw) {
   if (object->IsJSArray()) {
     return JSArray::DefineOwnProperty(isolate, Handle<JSArray>::cast(object),
                                       key, desc, should_throw);
   }
+  if (object->IsJSProxy()) {
+    return JSProxy::DefineOwnProperty(isolate, Handle<JSProxy>::cast(object),
+                                      key, desc, should_throw);
+  }
   // TODO(jkummerow): Support Modules (ES6 9.4.6.6)
-  // TODO(jkummerow): Support Proxies (ES6 9.5.6)
   if (!object->IsJSObject()) return true;

[neis, 2015/11/17 21:37:40]

This condition will now always be false.

[Jakob Kummerow, 2015/11/18 14:35:50]

Done.

 
   // OrdinaryDefineOwnProperty, by virtue of calling
   // DefineOwnPropertyIgnoreAttributes, can handle arguments (ES6 9.4.4.2)
   // and IntegerIndexedExotics (ES6 9.4.5.3), with one exception:
   // TODO(jkummerow): Setting an indexed accessor on a typed array should throw.
   return OrdinaryDefineOwnProperty(isolate, Handle<JSObject>::cast(object), key,
                                    desc, should_throw);
 }
 
 
@@ skipping 560 matching lines @@
   success = actual_new_len == new_len;
   if (!success && should_throw == THROW_ON_ERROR) {
     isolate->Throw(*isolate->factory()->NewTypeError(
         MessageTemplate::kStrictDeleteProperty,
         isolate->factory()->NewNumberFromUint(actual_new_len - 1), a));
   }
   return success;
 }
 
 
+// ES6 9.5.6
+// static
+bool JSProxy::DefineOwnProperty(Isolate* isolate, Handle<JSProxy> object,
+                                Handle<Object> key, PropertyDescriptor* desc,
+                                ShouldThrow should_throw) {
+  // 1. Assert: IsPropertyKey(P) is true.
+  DCHECK(key->IsName() || key->IsNumber());
+  // 2. Let handler be the value of the [[ProxyHandler]] internal slot of O.
+  Handle<Object> handler(object->handler(), isolate);
+  // 3. If handler is null, throw a TypeError exception.

[neis, 2015/11/17 21:37:40]

I would prefer using an IsRevoked function here.

[Jakob Kummerow, 2015/11/18 14:35:50]

Yeah, well, we don't have that yet. I've added a TODO.

+  if (handler->IsNull()) {
+    isolate->Throw(*isolate->factory()->NewTypeError(
+        MessageTemplate::kProxyHandlerNonObject));
+    return false;
+  }
+  // 4. Assert: Type(handler) is Object.
+  DCHECK(handler->IsJSReceiver());
+  // If the handler is not null, the target can't be null either.
+  DCHECK(object->target()->IsSpecObject());

[neis, 2015/11/17 21:37:40]

What is the relationship between IsSpecObject and IsJSReceiver?

[Jakob Kummerow, 2015/11/18 14:35:50]

They're identical. Consolidating the entire codebase on one of them is a
long-standing cleanup TODO.

+  // 5. Let target be the value of the [[ProxyTarget]] internal slot of O.
+  Handle<JSReceiver> target(JSReceiver::cast(object->target()), isolate);
+  // 6. Let trap be ? GetMethod(handler, "defineProperty").
+  Handle<Object> trap;
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate, trap,
+      Object::GetMethod(Handle<JSReceiver>::cast(handler),
+                        isolate->factory()->defineProperty_string()),
+      false);
+  // 7. If trap is undefined, then:
+  if (trap->IsUndefined()) {
+    // 7a. Return target.[[DefineOwnProperty]](P, Desc).
+    return JSReceiver::DefineOwnProperty(isolate, target, key, desc,
+                                         should_throw);
+  }
+  // 8. Let descObj be FromPropertyDescriptor(Desc).
+  Handle<Object> desc_obj = desc->ToObject(isolate);
+  // 9. Let booleanTrapResult be
+  //    ToBoolean(? Call(trap, handler, «target, P, descObj»)).
+  Handle<Name> property_name =
+      key->IsName()
+          ? Handle<Name>::cast(key)
+          : Handle<Name>::cast(isolate->factory()->NumberToString(key));
+  Handle<Object> trap_result_obj;
+  Handle<Object> args[] = {target, property_name, desc_obj};
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate, trap_result_obj,
+      Execution::Call(isolate, trap, handler, arraysize(args), args), false);
+  // 10. If booleanTrapResult is false, return false.
+  if (trap_result_obj->BooleanValue() == false) {

[neis, 2015/11/17 21:37:40]

if (!...)

[Jakob Kummerow, 2015/11/18 14:35:50]

Done. (I was intentionally staying close to the spec, but I don't care much.)

+    if (should_throw == THROW_ON_ERROR) {
+      // TODO(jkummerow): Better error message?
+      isolate->Throw(*isolate->factory()->NewTypeError(
+          MessageTemplate::kProxyHandlerReturned, handler, trap_result_obj,
+          key));
+    }
+    return false;
+  }
+  // 11. Let targetDesc be ? target.[[GetOwnProperty]](P).
+  PropertyDescriptor target_desc;
+  bool target_found =
+      JSReceiver::GetOwnPropertyDescriptor(isolate, target, key, &target_desc);
+  if (isolate->has_pending_exception()) return false;
+  // 12. Let extensibleTarget be ? IsExtensible(target).
+  Maybe<bool> maybe_extensible = JSReceiver::IsExtensible(target);
+  if (maybe_extensible.IsNothing()) return false;
+  bool extensible_target = maybe_extensible.FromJust();
+  // 13. If Desc has a [[Configurable]] field and if Desc.[[Configurable]]
+  //     is false, then:
+  // 13a. Let settingConfigFalse be true.
+  // 14. Else let settingConfigFalse be false.
+  bool setting_config_false = desc->has_configurable() && !desc->configurable();
+  // 15. If targetDesc is undefined, then
+  if (!target_found) {
+    // 15a. If extensibleTarget is false, throw a TypeError exception.
+    if (!extensible_target) {
+      isolate->Throw(*isolate->factory()->NewTypeError(
+          MessageTemplate::kProxyTargetNotExtensible));
+      return false;
+    }
+    // 15b. If settingConfigFalse is true, throw a TypeError exception.
+    if (setting_config_false) {
+      // TODO(jkummerow): Better error message?
+      isolate->Throw(*isolate->factory()->NewTypeError(
+          MessageTemplate::kRedefineDisallowed, key));
+      return false;
+    }
+  } else {
+    // 16. Else targetDesc is not undefined,
+    // 16a. If IsCompatiblePropertyDescriptor(extensibleTarget, Desc,
+    //      targetDesc) is false, throw a TypeError exception.
+    bool valid = IsCompatiblePropertyDescriptor(
+        isolate, extensible_target, desc, &target_desc, property_name);
+    if (!valid) {
+      DCHECK(isolate->has_pending_exception());
+      return false;
+    }
+    // 16b. If settingConfigFalse is true and targetDesc.[[Configurable]] is
+    //      true, throw a TypeError exception.
+    if (setting_config_false && target_desc.configurable()) {
+      // TODO(jkummerow): Better error message?
+      isolate->Throw(*isolate->factory()->NewTypeError(
+          MessageTemplate::kRedefineDisallowed, key));
+      return false;
+    }
+  }
+  // 17. Return true.
+  return true;
+}
+
+
 // static
 bool JSReceiver::GetOwnPropertyDescriptor(Isolate* isolate,
                                           Handle<JSReceiver> object,
                                           Handle<Object> key,
                                           PropertyDescriptor* desc) {
   bool success = false;
   DCHECK(key->IsName() || key->IsNumber());  // |key| is a PropertyKey...
   LookupIterator it = LookupIterator::PropertyOrElement(
       isolate, object, key, &success, LookupIterator::HIDDEN);
   DCHECK(success);  // ...so creating a LookupIterator can't fail.
@@ skipping 11471 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