test.cpp

// Copyright 2015 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.

// static
MaybeHandle<Object> JSProxy::GetProperty(Isolate* isolate,
                                         Handle<JSProxy> proxy,
                                         Handle<Name> name,
                                         Handle<Object> receiver,
                                         bool* was_found) {
  *was_found = true;
  if (receiver->IsJSGlobalObject()) {
    THROW_NEW_ERROR(
        isolate,
        NewTypeError(MessageTemplate::kReadGlobalReferenceThroughProxy, name),
        Object);
  }

  DCHECK(!name->IsPrivate());
  STACK_CHECK(isolate, MaybeHandle<Object>());
  Handle<Name> trap_name = isolate->factory()->get_string();
  // 1. Assert: IsPropertyKey(P) is true.
  // 2. Let handler be the value of the [[ProxyHandler]] internal slot of O.
  Handle<Object> handler(proxy->handler(), isolate);
  // 3. If handler is null, throw a TypeError exception.
  // 4. Assert: Type(handler) is Object.
  if (proxy->IsRevoked()) {
    THROW_NEW_ERROR(isolate,
                    NewTypeError(MessageTemplate::kProxyRevoked, trap_name),
                    Object);
  }
  // 5. Let target be the value of the [[ProxyTarget]] internal slot of O.
  Handle<JSReceiver> target(proxy->target(), isolate);
  // 6. Let trap be ? GetMethod(handler, "get").
  Handle<Object> trap;
  ASSIGN_RETURN_ON_EXCEPTION(
      isolate, trap,
      Object::GetMethod(Handle<JSReceiver>::cast(handler), trap_name), Object);
  // 7. If trap is undefined, then
  if (trap->IsUndefined(isolate)) {
    // 7.a Return target.[[Get]](P, Receiver).
    LookupIterator it =
        LookupIterator::PropertyOrElement(isolate, receiver, name, target);
    MaybeHandle<Object> result = Object::GetProperty(&it);
    *was_found = it.IsFound();
    return result;
  }
  // 8. Let trapResult be ? Call(trap, handler, «target, P, Receiver»).
  Handle<Object> trap_result;
  Handle<Object> args[] = {target, name, receiver};
  ASSIGN_RETURN_ON_EXCEPTION(
      isolate, trap_result,
      Execution::Call(isolate, trap, handler, arraysize(args), args), Object);
  // 9. Let targetDesc be ? target.[[GetOwnProperty]](P).
  PropertyDescriptor target_desc;
  Maybe<bool> target_found =
      JSReceiver::GetOwnPropertyDescriptor(isolate, target, name, &target_desc);
  MAYBE_RETURN_NULL(target_found);
  // 10. If targetDesc is not undefined, then
  if (target_found.FromJust()) {
    // 10.a. If IsDataDescriptor(targetDesc) and targetDesc.[[Configurable]] is
    //       false and targetDesc.[[Writable]] is false, then
    // 10.a.i. If SameValue(trapResult, targetDesc.[[Value]]) is false,
    //        throw a TypeError exception.
    bool inconsistent = PropertyDescriptor::IsDataDescriptor(&target_desc) &&
                        !target_desc.configurable() &&
                        !target_desc.writable() &&
                        !trap_result->SameValue(*target_desc.value());
    if (inconsistent) {
      THROW_NEW_ERROR(
          isolate, NewTypeError(MessageTemplate::kProxyGetNonConfigurableData,
                                name, target_desc.value(), trap_result),
          Object);
    }
    // 10.b. If IsAccessorDescriptor(targetDesc) and targetDesc.[[Configurable]]
    //       is false and targetDesc.[[Get]] is undefined, then
    // 10.b.i. If trapResult is not undefined, throw a TypeError exception.
    inconsistent = PropertyDescriptor::IsAccessorDescriptor(&target_desc) &&
!target_desc.configurable() &&
target_desc.get()->IsUndefined(isolate) &&
!trap_result->IsUndefined(isolate);
    if (inconsistent) {
      THROW_NEW_ERROR(
          isolate,
          NewTypeError(MessageTemplate::kProxyGetNonConfigurableAccessor, name,
                       trap_result),
          Object);
    }
  }
  // 11. Return trap_result
  return trap_result;
}