ladybird/Userland/Libraries/LibWeb/DOM/AbortSignal.cpp
Luke Wilde dce6327ae7 LibWeb: Add the ability for an AbortSignal to follow another
Following another abort signal basically means to make an abort signal
abort when another abort signal is aborted, unless the following signal
is already aborted.
2022-10-26 18:49:41 +01:00

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/*
* Copyright (c) 2021, Luke Wilde <lukew@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/DOM/AbortSignal.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/DOM/EventDispatcher.h>
#include <LibWeb/HTML/EventHandler.h>
namespace Web::DOM {
JS::NonnullGCPtr<AbortSignal> AbortSignal::construct_impl(JS::Realm& realm)
{
return *realm.heap().allocate<AbortSignal>(realm, realm);
}
AbortSignal::AbortSignal(JS::Realm& realm)
: EventTarget(realm)
{
set_prototype(&Bindings::cached_web_prototype(realm, "AbortSignal"));
}
// https://dom.spec.whatwg.org/#abortsignal-add
void AbortSignal::add_abort_algorithm(JS::SafeFunction<void()> abort_algorithm)
{
// 1. If signal is aborted, then return.
if (aborted())
return;
// 2. Append algorithm to signals abort algorithms.
m_abort_algorithms.append(move(abort_algorithm));
}
// https://dom.spec.whatwg.org/#abortsignal-signal-abort
void AbortSignal::signal_abort(JS::Value reason)
{
// 1. If signal is aborted, then return.
if (aborted())
return;
// 2. Set signals abort reason to reason if it is given; otherwise to a new "AbortError" DOMException.
if (!reason.is_undefined())
m_abort_reason = reason;
else
m_abort_reason = WebIDL::AbortError::create(realm(), "Aborted without reason").ptr();
// 3. For each algorithm in signals abort algorithms: run algorithm.
for (auto& algorithm : m_abort_algorithms)
algorithm();
// 4. Empty signals abort algorithms.
m_abort_algorithms.clear();
// 5. Fire an event named abort at signal.
dispatch_event(*Event::create(realm(), HTML::EventNames::abort));
}
void AbortSignal::set_onabort(WebIDL::CallbackType* event_handler)
{
set_event_handler_attribute(HTML::EventNames::abort, event_handler);
}
WebIDL::CallbackType* AbortSignal::onabort()
{
return event_handler_attribute(HTML::EventNames::abort);
}
// https://dom.spec.whatwg.org/#dom-abortsignal-throwifaborted
JS::ThrowCompletionOr<void> AbortSignal::throw_if_aborted() const
{
// The throwIfAborted() method steps are to throw thiss abort reason, if this is aborted.
if (!aborted())
return {};
return JS::throw_completion(m_abort_reason);
}
void AbortSignal::visit_edges(JS::Cell::Visitor& visitor)
{
Base::visit_edges(visitor);
visitor.visit(m_abort_reason);
}
// https://dom.spec.whatwg.org/#abortsignal-follow
void AbortSignal::follow(JS::NonnullGCPtr<AbortSignal> parent_signal)
{
// A followingSignal (an AbortSignal) is made to follow a parentSignal (an AbortSignal) by running these steps:
// 1. If followingSignal is aborted, then return.
if (aborted())
return;
// 2. If parentSignal is aborted, then signal abort on followingSignal with parentSignals abort reason.
if (parent_signal->aborted()) {
signal_abort(parent_signal->reason());
return;
}
// 3. Otherwise, add the following abort steps to parentSignal:
// NOTE: `this` and `parent_signal` are protected by AbortSignal using JS::SafeFunction.
parent_signal->add_abort_algorithm([this, parent_signal]() mutable {
// 1. Signal abort on followingSignal with parentSignals abort reason.
signal_abort(parent_signal->reason());
});
}
}