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/*
* Copyright (C) 2020-2022 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 "JSInternalFieldObjectImpl.h"
namespace JSC {
class JSFinalizationRegistry final : public JSInternalFieldObjectImpl<1> {
public:
using Base = JSInternalFieldObjectImpl<1>;
enum class Field : uint8_t {
Callback,
};
static size_t allocationSize(Checked<size_t> inlineCapacity)
{
ASSERT_UNUSED(inlineCapacity, inlineCapacity == 0U);
return sizeof(JSFinalizationRegistry);
}
template<typename CellType, SubspaceAccess mode>
static GCClient::IsoSubspace* subspaceFor(VM& vm)
{
return vm.finalizationRegistrySpace<mode>();
}
static std::array<JSValue, numberOfInternalFields> initialValues()
{
return { {
jsNull(),
} };
}
const WriteBarrier<Unknown>& internalField(Field field) const { return Base::internalField(static_cast<uint32_t>(field)); }
WriteBarrier<Unknown>& internalField(Field field) { return Base::internalField(static_cast<uint32_t>(field)); }
JSObject* callback() const { return jsCast<JSObject*>(internalField(Field::Callback).get()); }
static JSFinalizationRegistry* create(VM&, Structure*, JSObject* callback);
static JSFinalizationRegistry* createWithInitialValues(VM&, Structure*);
static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);
void runFinalizationCleanup(JSGlobalObject*);
DECLARE_EXPORT_INFO;
void finalizeUnconditionally(VM&, CollectionScope);
DECLARE_VISIT_CHILDREN;
static void destroy(JSCell*);
static constexpr DestructionMode needsDestruction = NeedsDestruction;
JSValue takeDeadHoldingsValue();
bool unregister(VM&, JSCell* token);
// token should be a JSObject, Symbol, or undefined.
void registerTarget(VM&, JSCell* target, JSValue holdings, JSValue token);
struct LiveRegistration {
JSCell* target;
JSValue heldValue;
JSCell* unregisterToken = nullptr;
};
JS_EXPORT_PRIVATE size_t liveCount(const Locker<JSCellLock>&);
Vector<LiveRegistration> liveRegistrations(const Locker<JSCellLock>&) const;
struct DeadRegistration {
JSValue heldValue;
JSCell* unregisterToken = nullptr;
};
JS_EXPORT_PRIVATE size_t deadCount(const Locker<JSCellLock>&);
Vector<DeadRegistration> deadRegistrations(const Locker<JSCellLock>&) const;
private:
JSFinalizationRegistry(VM& vm, Structure* structure)
: Base(vm, structure)
{
}
JS_EXPORT_PRIVATE void finishCreation(VM&, JSGlobalObject*, JSObject* callback);
struct Registration {
JSCell* target;
WriteBarrier<Unknown> holdings;
};
using LiveRegistrations = Vector<Registration>;
// We don't need the target anymore since we know it's dead.
using DeadRegistrations = Vector<WriteBarrier<Unknown>>;
// Note that we don't bother putting a write barrier on the key or target because they are weakly referenced.
UncheckedKeyHashMap<JSCell*, LiveRegistrations> m_liveRegistrations;
UncheckedKeyHashMap<JSCell*, DeadRegistrations> m_deadRegistrations;
// We use a separate list for no unregister values instead of a special key in the tables above because the UncheckedKeyHashMap has a tendency to reallocate under us when iterating...
LiveRegistrations m_noUnregistrationLive;
DeadRegistrations m_noUnregistrationDead;
bool m_hasAlreadyScheduledWork { false };
};
} // namespace JSC
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