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/*
* Copyright (C) 2019-2021 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 "JSWeakObjectRef.h"
#include "JSCInlines.h"
namespace JSC {
const ClassInfo JSWeakObjectRef::s_info = { "WeakRef"_s, &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSWeakObjectRef) };
void JSWeakObjectRef::finishCreation(VM& vm, JSCell* value)
{
m_lastAccessVersion = vm.currentWeakRefVersion();
m_value.set(vm, this, value);
Base::finishCreation(vm);
}
template<typename Visitor>
void JSWeakObjectRef::visitChildrenImpl(JSCell* cell, Visitor& visitor)
{
auto* thisObject = jsCast<JSWeakObjectRef*>(cell);
ASSERT_GC_OBJECT_INHERITS(thisObject, info());
Base::visitChildren(thisObject, visitor);
// This doesn't need to be atomic because if we are out of date we will get write barriered and revisit ourselves.
if (visitor.vm().currentWeakRefVersion() == thisObject->m_lastAccessVersion) {
ASSERT(thisObject->m_value);
visitor.append(thisObject->m_value);
}
}
DEFINE_VISIT_CHILDREN(JSWeakObjectRef);
void JSWeakObjectRef::finalizeUnconditionally(VM& vm, CollectionScope)
{
if (m_value && !vm.heap.isMarked(m_value.get()))
m_value.clear();
}
}
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