src/third_party/v8/src/builtins/proxy-set-prototype-of.tq

// Copyright 2019 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/builtins/builtins-proxy-gen.h'

namespace proxy {

// ES #sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v
// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v
transitioning builtin
ProxySetPrototypeOf(implicit context: Context)(
    proxy: JSProxy, proto: Null|JSReceiver, doThrow: Boolean): JSAny {
  PerformStackCheck();
  const kTrapName: constexpr string = 'setPrototypeOf';
  try {
    // 1. Assert: Either Type(V) is Object or Type(V) is Null.
    assert(proto == Null || Is<JSReceiver>(proto));

    // 2. Let handler be O.[[ProxyHandler]].
    // 3. If handler is null, throw a TypeError exception.
    // 4. Assert: Type(handler) is Object.
    assert(proxy.handler == Null || Is<JSReceiver>(proxy.handler));
    const handler =
        Cast<JSReceiver>(proxy.handler) otherwise ThrowProxyHandlerRevoked;

    // 5. Let target be O.[[ProxyTarget]].
    const target = proxy.target;

    // 6. Let trap be ? GetMethod(handler, "setPrototypeOf").
    // 7. If trap is undefined, then (see 7.a below).
    const trap: Callable = GetMethod(handler, kTrapName)
        otherwise goto TrapUndefined(target, proto);

    // 8. Let booleanTrapResult be ToBoolean(? Call(trap, handler, « target, V
    // »)).
    const trapResult = Call(context, trap, handler, target, proto);

    // 9. If booleanTrapResult is false, return false.
    if (!ToBoolean(trapResult)) {
      if (doThrow == True) {
        ThrowTypeError(
            MessageTemplate::kProxyTrapReturnedFalsishFor, kTrapName);
      }
      return False;
    }

    // 10. Let extensibleTarget be ? IsExtensible(target).
    // 11. If extensibleTarget is true, return true.
    const extensibleTarget: Object = object::ObjectIsExtensibleImpl(target);
    assert(extensibleTarget == True || extensibleTarget == False);
    if (extensibleTarget == True) {
      return True;
    }

    // 12. Let targetProto be ? target.[[GetPrototypeOf]]().
    const targetProto = object::ObjectGetPrototypeOfImpl(target);

    // 13. If SameValue(V, targetProto) is false, throw a TypeError
    // exception.
    // 14. Return true.
    if (SameValue(proto, targetProto)) {
      return True;
    }
    ThrowTypeError(MessageTemplate::kProxySetPrototypeOfNonExtensible);
  } label TrapUndefined(target: JSAny, proto: JSReceiver|Null) {
    // 7.a. Return ? target.[[SetPrototypeOf]]().
    if (doThrow == True) {
      return object::ObjectSetPrototypeOfThrow(target, proto);
    }
    return object::ObjectSetPrototypeOfDontThrow(target, proto);
  } label ThrowProxyHandlerRevoked deferred {
    ThrowTypeError(MessageTemplate::kProxyRevoked, kTrapName);
  }
}
}