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/*
* Copyright (C) 2015 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. AND ITS CONTRIBUTORS ``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 ITS 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.
*/
#ifndef VNodeTracker_h
#define VNodeTracker_h
#include "MemoryPressureHandler.h"
#include "Timer.h"
#include <chrono>
#include <wtf/Forward.h>
#include <wtf/RefCounter.h>
namespace WebCore {
class VNodeTracker {
friend class WTF::NeverDestroyed<VNodeTracker>;
public:
using PressureHandler = std::function<void(Critical)>;
enum TokenType { };
using Token = RefCounter::Token<TokenType>;
WEBCORE_EXPORT static VNodeTracker& singleton();
void setPressureHandler(PressureHandler);
Token token();
private:
VNodeTracker();
void checkPressureState();
void pressureWarningTimerFired();
std::chrono::milliseconds nextPressureWarningInterval() const;
void platformInitialize();
unsigned m_hardVNodeLimit { 400 };
unsigned m_softVNodeLimit { 300 };
PressureHandler m_pressureHandler;
RefCounter m_vnodeCounter;
Timer m_pressureWarningTimer;
std::chrono::steady_clock::time_point m_lastWarningTime;
};
inline void VNodeTracker::setPressureHandler(PressureHandler handler)
{
m_pressureHandler = handler;
}
inline auto VNodeTracker::token() -> Token
{
if (!m_pressureHandler)
return Token();
Token token(m_vnodeCounter.token<TokenType>());
checkPressureState();
return token;
}
} // namespace WebCore
#endif // VNodeTracker_h
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