src/builtins/proxy-has-property.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-hasproperty-p
  // https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p
  transitioning builtin ProxyHasProperty(implicit context: Context)(
      proxy: JSProxy, name: Name): Object {
    assert(IsJSProxy(proxy));

    PerformStackCheck();

    // 1. Assert: IsPropertyKey(P) is true.
    assert(IsName(name));
    assert(!IsPrivateSymbol(name));

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

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

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

      // 8. Let booleanTrapResult be ToBoolean(? Call(trap, handler, «
      // target»)).
      // 9. If booleanTrapResult is false, then (see 9.a. in
      // CheckHasTrapResult).
      // 10. Return booleanTrapResult.
      const trapResult = Call(context, trap, handler, target, name);
      if (BranchIfToBooleanIsTrue(trapResult)) {
        return True;
      }
      return CheckHasTrapResult(target, proxy, name);
    }
    label TrapUndefined(target: Object) {
      // 7.a. Return ? target.[[HasProperty]](P).
      tail HasProperty(target, name);
    }
    label ThrowProxyHandlerRevoked deferred {
      ThrowTypeError(kProxyRevoked, 'has');
    }
  }
}