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/*
* Copyright (C) 2017-2021 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "DeferredWorkTimer.h"
#include "JSPromise.h"
#include "StrongInlines.h"
#include "VM.h"
#include <wtf/RunLoop.h>
namespace JSC {
namespace DeferredWorkTimerInternal {
static const bool verbose = false;
}
inline DeferredWorkTimer::TicketData::TicketData(VM& vm, JSObject* scriptExecutionOwner, Vector<Strong<JSCell>>&& dependencies)
: dependencies(WTFMove(dependencies))
, scriptExecutionOwner(vm, scriptExecutionOwner)
{
}
inline VM& DeferredWorkTimer::TicketData::vm()
{
ASSERT(!isCancelled());
return target()->vm();
}
inline void DeferredWorkTimer::TicketData::cancel()
{
scriptExecutionOwner.clear();
dependencies.clear();
}
DeferredWorkTimer::DeferredWorkTimer(VM& vm)
: Base(vm)
{
}
void DeferredWorkTimer::doWork(VM& vm)
{
ASSERT(vm.currentThreadIsHoldingAPILock());
Locker locker { m_taskLock };
cancelTimer();
if (!m_runTasks)
return;
Vector<std::tuple<Ticket, Task>> suspendedTasks;
while (!m_tasks.isEmpty()) {
auto [ticket, task] = m_tasks.takeFirst();
dataLogLnIf(DeferredWorkTimerInternal::verbose, "Doing work on: ", RawPointer(ticket));
auto pendingTicket = m_pendingTickets.find(ticket);
// We may have already canceled this task or its owner may have been canceled.
if (pendingTicket == m_pendingTickets.end())
continue;
ASSERT(ticket == pendingTicket->get());
if (ticket->isCancelled()) {
m_pendingTickets.remove(pendingTicket);
continue;
}
// We shouldn't access the TicketData to get this globalObject until
// after we confirm that the ticket is still valid (which we did above).
auto globalObject = ticket->target()->structure(vm)->globalObject();
switch (globalObject->globalObjectMethodTable()->scriptExecutionStatus(globalObject, ticket->scriptExecutionOwner.get())) {
case ScriptExecutionStatus::Suspended:
suspendedTasks.append(std::make_tuple(ticket, WTFMove(task)));
continue;
case ScriptExecutionStatus::Stopped:
m_pendingTickets.remove(pendingTicket);
continue;
case ScriptExecutionStatus::Running:
break;
}
// Remove ticket from m_pendingTickets since we are going to run it.
// But we want to keep ticketData while running task since it ensures dependencies are strongly held.
std::unique_ptr<TicketData> ticketData = m_pendingTickets.take(pendingTicket);
// Allow tasks we are about to run to schedule work.
m_currentlyRunningTask = true;
{
auto dropper = DropLockForScope(locker);
// This is the start of a runloop turn, we can release any weakrefs here.
vm.finalizeSynchronousJSExecution();
auto scope = DECLARE_CATCH_SCOPE(vm);
task(ticket);
ticketData = nullptr;
if (Exception* exception = scope.exception()) {
scope.clearException();
globalObject->globalObjectMethodTable()->reportUncaughtExceptionAtEventLoop(globalObject, exception);
}
vm.drainMicrotasks();
ASSERT(!vm.exceptionForInspection());
}
m_currentlyRunningTask = false;
}
while (!suspendedTasks.isEmpty())
m_tasks.prepend(suspendedTasks.takeLast());
// It is theoretically possible that a client may cancel a pending ticket and
// never call scheduleWorkSoon() on it. As such, it would not be found when
// we iterated m_tasks above. We'll need to make sure to purge them here.
m_pendingTickets.removeIf([] (auto& ticket) {
return ticket->isCancelled();
});
if (m_pendingTickets.isEmpty() && m_shouldStopRunLoopWhenAllTicketsFinish) {
ASSERT(m_tasks.isEmpty());
RunLoop::current().stop();
}
}
void DeferredWorkTimer::runRunLoop()
{
ASSERT(!m_apiLock->vm()->currentThreadIsHoldingAPILock());
ASSERT(&RunLoop::current() == &m_apiLock->vm()->runLoop());
m_shouldStopRunLoopWhenAllTicketsFinish = true;
if (m_pendingTickets.size())
RunLoop::run();
}
DeferredWorkTimer::Ticket DeferredWorkTimer::addPendingWork(VM& vm, JSObject* target, Vector<Strong<JSCell>>&& dependencies)
{
ASSERT(vm.currentThreadIsHoldingAPILock() || (Thread::mayBeGCThread() && vm.heap.worldIsStopped()));
for (unsigned i = 0; i < dependencies.size(); ++i)
ASSERT(dependencies[i].get() != target);
auto* globalObject = target->globalObject();
JSObject* scriptExecutionOwner = globalObject->globalObjectMethodTable()->currentScriptExecutionOwner(globalObject);
dependencies.append(Strong<JSCell>(vm, target));
auto ticketData = makeUnique<TicketData>(vm, scriptExecutionOwner, WTFMove(dependencies));
Ticket ticket = ticketData.get();
dataLogLnIf(DeferredWorkTimerInternal::verbose, "Adding new pending ticket: ", RawPointer(ticket));
auto result = m_pendingTickets.add(WTFMove(ticketData));
RELEASE_ASSERT(result.isNewEntry);
return ticket;
}
bool DeferredWorkTimer::hasPendingWork(Ticket ticket)
{
auto result = m_pendingTickets.find(ticket);
if (result == m_pendingTickets.end() || ticket->isCancelled())
return false;
ASSERT(ticket->vm().currentThreadIsHoldingAPILock() || (Thread::mayBeGCThread() && ticket->vm().heap.worldIsStopped()));
return true;
}
bool DeferredWorkTimer::hasDependancyInPendingWork(Ticket ticket, JSCell* dependency)
{
auto result = m_pendingTickets.find(ticket);
if (result == m_pendingTickets.end() || ticket->isCancelled())
return false;
ASSERT(ticket->vm().currentThreadIsHoldingAPILock() || (Thread::mayBeGCThread() && ticket->vm().heap.worldIsStopped()));
return (*result)->dependencies.contains(dependency);
}
void DeferredWorkTimer::scheduleWorkSoon(Ticket ticket, Task&& task)
{
Locker locker { m_taskLock };
m_tasks.append(std::make_tuple(ticket, WTFMove(task)));
if (!isScheduled() && !m_currentlyRunningTask)
setTimeUntilFire(0_s);
}
bool DeferredWorkTimer::cancelPendingWork(Ticket ticket)
{
ASSERT(m_pendingTickets.contains(ticket));
ASSERT(ticket->isCancelled() || ticket->vm().currentThreadIsHoldingAPILock() || (Thread::mayBeGCThread() && ticket->vm().heap.worldIsStopped()));
bool result = false;
if (!ticket->isCancelled()) {
dataLogLnIf(DeferredWorkTimerInternal::verbose, "Canceling ticket: ", RawPointer(ticket));
ticket->cancel();
result = true;
}
return result;
}
void DeferredWorkTimer::didResumeScriptExecutionOwner()
{
ASSERT(!m_currentlyRunningTask);
Locker locker { m_taskLock };
if (!isScheduled() && m_tasks.size())
setTimeUntilFire(0_s);
}
} // namespace JSC