mirror of
https://github.com/darlinghq/darling-JavaScriptCore.git
synced 2025-04-09 02:10:43 +00:00
96 lines
2.8 KiB
C++
96 lines
2.8 KiB
C++
/*
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* Copyright (C) 2011, 2016 Apple Inc. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#pragma once
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#include "CallFrame.h"
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#include "GetVM.h"
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#include "VMInlines.h"
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#include <wtf/StackStats.h>
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namespace JSC {
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class StringRecursionChecker {
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WTF_MAKE_NONCOPYABLE(StringRecursionChecker);
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public:
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StringRecursionChecker(JSGlobalObject*, JSObject* thisObject);
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~StringRecursionChecker();
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JSValue earlyReturnValue() const; // 0 if everything is OK, value to return for failure cases
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private:
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JSValue throwStackOverflowError();
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JSValue emptyString();
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JSValue performCheck();
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JSGlobalObject* m_globalObject;
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JSObject* m_thisObject;
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JSValue m_earlyReturnValue;
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StackStats::CheckPoint stackCheckpoint;
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};
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inline JSValue StringRecursionChecker::performCheck()
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{
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VM& vm = getVM(m_globalObject);
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if (UNLIKELY(!vm.isSafeToRecurseSoft()))
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return throwStackOverflowError();
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bool alreadyVisited = false;
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if (!vm.stringRecursionCheckFirstObject)
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vm.stringRecursionCheckFirstObject = m_thisObject;
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else if (vm.stringRecursionCheckFirstObject == m_thisObject)
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alreadyVisited = true;
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else
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alreadyVisited = !vm.stringRecursionCheckVisitedObjects.add(m_thisObject).isNewEntry;
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if (alreadyVisited)
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return emptyString(); // Return empty string to avoid infinite recursion.
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return JSValue(); // Indicate success.
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}
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inline StringRecursionChecker::StringRecursionChecker(JSGlobalObject* globalObject, JSObject* thisObject)
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: m_globalObject(globalObject)
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, m_thisObject(thisObject)
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, m_earlyReturnValue(performCheck())
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{
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}
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inline JSValue StringRecursionChecker::earlyReturnValue() const
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{
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return m_earlyReturnValue;
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}
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inline StringRecursionChecker::~StringRecursionChecker()
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{
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if (m_earlyReturnValue)
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return;
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VM& vm = getVM(m_globalObject);
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if (vm.stringRecursionCheckFirstObject == m_thisObject)
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vm.stringRecursionCheckFirstObject = nullptr;
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else {
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ASSERT(vm.stringRecursionCheckVisitedObjects.contains(m_thisObject));
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vm.stringRecursionCheckVisitedObjects.remove(m_thisObject);
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}
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}
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} // namespace JSC
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