1/*
2 * Copyright (C) 2019 Apple, Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "JSWeakObjectRef.h"
28
29#include "JSCInlines.h"
30
31namespace JSC {
32
33const ClassInfo JSWeakObjectRef::s_info = { "WeakRef", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSWeakObjectRef) };
34
35void JSWeakObjectRef::finishCreation(VM& vm, JSObject* value)
36{
37 m_lastAccessVersion = vm.currentWeakRefVersion();
38 m_value.set(vm, this, value);
39 Base::finishCreation(vm);
40}
41
42void JSWeakObjectRef::visitChildren(JSCell* cell, SlotVisitor& visitor)
43{
44 auto* thisObject = jsCast<JSWeakObjectRef*>(cell);
45 ASSERT_GC_OBJECT_INHERITS(thisObject, info());
46 Base::visitChildren(thisObject, visitor);
47 // This doesn't need to be atomic because if we are out of date we will get write barriered and revisit ourselves.
48 if (visitor.vm().currentWeakRefVersion() == thisObject->m_lastAccessVersion) {
49 ASSERT(thisObject->m_value);
50 visitor.append(thisObject->m_value);
51 }
52}
53
54void JSWeakObjectRef::finalizeUnconditionally(VM& vm)
55{
56 if (m_value && !vm.heap.isMarked(m_value.get()))
57 m_value.clear();
58}
59
60String JSWeakObjectRef::toStringName(const JSC::JSObject*, ExecState*)
61{
62 return "Object"_s;
63}
64
65}
66
67