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// 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-preventextensions
// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-preventextensions
transitioning builtin
ProxyPreventExtensions(implicit context: Context)(
proxy: JSProxy, doThrow: Boolean): Object {
PerformStackCheck();
const kTrapName: constexpr string = 'preventExtensions';
try {
// 1. Let handler be O.[[ProxyHandler]].
// 2. If handler is null, throw a TypeError exception.
// 3. Assert: Type(handler) is Object.
assert(proxy.handler == Null || Is<JSReceiver>(proxy.handler));
const handler =
Cast<JSReceiver>(proxy.handler) otherwise ThrowProxyHandlerRevoked;
// 4. Let target be O.[[ProxyTarget]].
const target = proxy.target;
// 5. Let trap be ? GetMethod(handler, "preventExtensions").
// 6. If trap is undefined, then (see 6.a below).
const trap: Callable = GetMethod(handler, kTrapName)
otherwise goto TrapUndefined(target);
// 7. Let booleanTrapResult be ToBoolean(? Call(trap, handler, «
// target»)).
const trapResult = Call(context, trap, handler, target);
// 8. If booleanTrapResult is true, then
// 8.a. Let extensibleTarget be ? IsExtensible(target).
// 8.b If extensibleTarget is true, throw a TypeError exception.
if (BranchIfToBooleanIsTrue(trapResult)) {
const extensibleTarget: Object = object::ObjectIsExtensible(target);
assert(extensibleTarget == True || extensibleTarget == False);
if (extensibleTarget == True) {
ThrowTypeError(kProxyPreventExtensionsExtensible);
}
} else {
if (doThrow == True) {
ThrowTypeError(kProxyTrapReturnedFalsish, kTrapName);
}
return False;
}
// 9. Return booleanTrapResult.
return True;
}
label TrapUndefined(target: Object) {
// 6.a. Return ? target.[[PreventExtensions]]().
if (doThrow == True) {
return object::ObjectPreventExtensionsThrow(target);
}
return object::ObjectPreventExtensionsDontThrow(target);
}
label ThrowProxyHandlerRevoked deferred {
ThrowTypeError(kProxyRevoked, kTrapName);
}
}
} // namespace proxy
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