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/*
* Copyright (C) 2014 Yoav Weiss (yoav@yoav.ws)
* Copyright (C) 2015 Akamai Technologies Inc. All rights reserved.
* Copyright (C) 2023 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "Microtasks.h"
#include "CommonVM.h"
#include "EventLoop.h"
#include "RejectedPromiseTracker.h"
#include "ScriptExecutionContext.h"
#include "WorkerGlobalScope.h"
#include <JavaScriptCore/CatchScope.h>
#include <wtf/MainThread.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/SetForScope.h>
namespace WebCore {
MicrotaskQueue::MicrotaskQueue(JSC::VM& vm, EventLoop& eventLoop)
: m_vm(vm)
, m_eventLoop(eventLoop)
{
}
MicrotaskQueue::~MicrotaskQueue() = default;
void MicrotaskQueue::append(std::unique_ptr<EventLoopTask>&& task)
{
m_microtaskQueue.append(WTFMove(task));
}
void MicrotaskQueue::performMicrotaskCheckpoint()
{
if (m_performingMicrotaskCheckpoint)
return;
SetForScope change(m_performingMicrotaskCheckpoint, true);
JSC::VM& vm = this->vm();
JSC::JSLockHolder locker(vm);
auto catchScope = DECLARE_CATCH_SCOPE(vm);
Vector<std::unique_ptr<EventLoopTask>> toKeep;
while (!m_microtaskQueue.isEmpty() && !vm.executionForbidden()) {
Vector<std::unique_ptr<EventLoopTask>> queue = WTFMove(m_microtaskQueue);
for (auto& task : queue) {
auto* group = task->group();
if (!group || group->isStoppedPermanently())
continue;
if (group->isSuspended())
toKeep.append(WTFMove(task));
else {
task->execute();
if (UNLIKELY(!catchScope.clearExceptionExceptTermination()))
break; // Encountered termination.
}
}
}
vm.finalizeSynchronousJSExecution();
m_microtaskQueue = WTFMove(toKeep);
if (!vm.executionForbidden()) {
auto checkpointTasks = std::exchange(m_checkpointTasks, { });
for (auto& checkpointTask : checkpointTasks) {
auto* group = checkpointTask->group();
if (!group || group->isStoppedPermanently())
continue;
if (group->isSuspended()) {
m_checkpointTasks.append(WTFMove(checkpointTask));
continue;
}
checkpointTask->execute();
if (UNLIKELY(!catchScope.clearExceptionExceptTermination()))
break; // Encountered termination.
}
}
// https://html.spec.whatwg.org/multipage/webappapis.html#perform-a-microtask-checkpoint (step 4).
auto* vmPtr = &vm;
m_eventLoop->forEachAssociatedContext([vmPtr](auto& context) {
auto& vm = *vmPtr;
if (UNLIKELY(vm.executionForbidden()))
return;
auto catchScope = DECLARE_CATCH_SCOPE(vm);
if (auto* tracker = context.rejectedPromiseTracker())
tracker->processQueueSoon();
catchScope.clearExceptionExceptTermination();
});
// FIXME: We should cleanup Indexed Database transactions as per:
// https://html.spec.whatwg.org/multipage/webappapis.html#perform-a-microtask-checkpoint (step 5).
}
void MicrotaskQueue::addCheckpointTask(std::unique_ptr<EventLoopTask>&& task)
{
m_checkpointTasks.append(WTFMove(task));
}
} // namespace WebCore
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