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/*
* Copyright (C) 2011 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifndef StringRecursionChecker_h
#define StringRecursionChecker_h
#include "Interpreter.h"
namespace JSC {
class StringRecursionChecker {
WTF_MAKE_NONCOPYABLE(StringRecursionChecker);
public:
StringRecursionChecker(ExecState*, JSObject* thisObject);
~StringRecursionChecker();
JSValue earlyReturnValue() const; // 0 if everything is OK, value to return for failure cases
private:
JSValue throwStackOverflowError();
JSValue emptyString();
JSValue performCheck();
ExecState* m_exec;
JSObject* m_thisObject;
JSValue m_earlyReturnValue;
};
inline JSValue StringRecursionChecker::performCheck()
{
int size = m_exec->globalData().stringRecursionCheckVisitedObjects.size();
if (size >= MaxSmallThreadReentryDepth && size >= m_exec->globalData().maxReentryDepth)
return throwStackOverflowError();
bool alreadyVisited = !m_exec->globalData().stringRecursionCheckVisitedObjects.add(m_thisObject).isNewEntry;
if (alreadyVisited)
return emptyString(); // Return empty string to avoid infinite recursion.
return JSValue(); // Indicate success.
}
inline StringRecursionChecker::StringRecursionChecker(ExecState* exec, JSObject* thisObject)
: m_exec(exec)
, m_thisObject(thisObject)
, m_earlyReturnValue(performCheck())
{
}
inline JSValue StringRecursionChecker::earlyReturnValue() const
{
return m_earlyReturnValue;
}
inline StringRecursionChecker::~StringRecursionChecker()
{
if (m_earlyReturnValue)
return;
ASSERT(m_exec->globalData().stringRecursionCheckVisitedObjects.contains(m_thisObject));
m_exec->globalData().stringRecursionCheckVisitedObjects.remove(m_thisObject);
}
}
#endif
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