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/*
* Copyright (C) 2017-2023 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.
*/
#pragma once
#include "JSRunLoopTimer.h"
#include "WeakInlines.h"
#include <wtf/Deque.h>
#include <wtf/FixedVector.h>
#include <wtf/HashSet.h>
#include <wtf/RefPtr.h>
#include <wtf/ThreadSafeWeakPtr.h>
#include <wtf/Vector.h>
namespace JSC {
class VM;
class JSCell;
class JSObject;
class JSGlobalObject;
class DeferredWorkTimer final : public JSRunLoopTimer {
public:
using Base = JSRunLoopTimer;
enum class WorkType : uint8_t {
ImminentlyScheduled,
AtSomePoint,
};
class TicketData : public ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr<TicketData> {
private:
WTF_MAKE_TZONE_ALLOCATED(TicketData);
WTF_MAKE_NONCOPYABLE(TicketData);
public:
inline static Ref<TicketData> create(WorkType, JSObject* scriptExecutionOwner, Vector<JSCell*>&& dependencies);
WorkType type() const { return m_type; }
inline VM& vm();
JSObject* target();
bool isTargetObject();
inline const FixedVector<JSCell*>& dependencies(bool mayBeCancelled = false);
inline JSObject* scriptExecutionOwner();
inline void cancel();
// We should not modify dependencies unless it is legitimate to do so during the end of GC.
inline void cancelAndClear();
bool isCancelled() const { return m_isCancelled; }
private:
inline TicketData(WorkType, JSObject* scriptExecutionOwner, Vector<JSCell*>&& dependencies);
WorkType m_type;
FixedVector<JSCell*> m_dependencies;
JSObject* m_scriptExecutionOwner { nullptr };
bool m_isCancelled { false };
};
using Ticket = TicketData*;
void doWork(VM&) final;
JS_EXPORT_PRIVATE Ticket addPendingWork(WorkType, VM&, JSObject* target, Vector<JSCell*>&& dependencies);
void cancelPendingWork(VM&);
JS_EXPORT_PRIVATE bool hasAnyPendingWork() const;
JS_EXPORT_PRIVATE bool hasImminentlyScheduledWork() const;
bool hasPendingWork(Ticket);
bool hasDependencyInPendingWork(Ticket, JSCell* dependency);
bool cancelPendingWork(Ticket);
void cancelPendingWorkSafe(JSGlobalObject*);
// If the script execution owner your ticket is associated with gets canceled
// the Task will not be called and will be deallocated. So it's important
// to make sure your memory ownership model won't leak memory when
// this occurs. The easiest way is to make sure everything is either owned
// by a GC'd value in dependencies or by the Task lambda.
using Task = Function<void(Ticket)>;
JS_EXPORT_PRIVATE void scheduleWorkSoon(Ticket, Task&&);
JS_EXPORT_PRIVATE void didResumeScriptExecutionOwner();
void stopRunningTasks() { m_runTasks = false; }
JS_EXPORT_PRIVATE void runRunLoop();
static Ref<DeferredWorkTimer> create(VM& vm) { return adoptRef(*new DeferredWorkTimer(vm)); }
private:
DeferredWorkTimer(VM&);
Lock m_taskLock;
bool m_runTasks { true };
bool m_shouldStopRunLoopWhenAllTicketsFinish { false };
bool m_currentlyRunningTask { false };
Deque<std::tuple<Ticket, Task>> m_tasks WTF_GUARDED_BY_LOCK(m_taskLock);
UncheckedKeyHashSet<Ref<TicketData>> m_pendingTickets;
};
inline JSObject* DeferredWorkTimer::TicketData::target()
{
ASSERT(!isCancelled() && isTargetObject());
// This function can be triggered on the main thread with a GC end phase
// and a sweeping state. So, jsCast is not wanted here.
return std::bit_cast<JSObject*>(m_dependencies.last());
}
inline const FixedVector<JSCell*>& DeferredWorkTimer::TicketData::dependencies(bool mayBeCancelled)
{
ASSERT_UNUSED(mayBeCancelled, mayBeCancelled || !isCancelled());
return m_dependencies;
}
inline JSObject* DeferredWorkTimer::TicketData::scriptExecutionOwner()
{
ASSERT(!isCancelled());
return m_scriptExecutionOwner;
}
} // namespace JSC
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