MemoryWatcher.h

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/* @@@LICENSE
*
*      Copyright (c) 2009-2012 Hewlett-Packard Development Company, L.P.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* LICENSE@@@ */




#ifndef MEMORYWATCHER_H
#define MEMORYWATCHER_H

#include "Common.h"

#include <stdint.h>
#include <map>

#include "SignalSlot.h"
#include "Timer.h"

#if defined(HAS_MEMCHUTE)
extern "C" {
#include <memchute.h>
}
#endif

class MemoryWatcher
{
public:

        enum MemState {
                Normal = 0,
                Medium,
                Low,
                Critical
        };

        static MemoryWatcher* instance();

        void start();
        
        MemState state() const { return m_state; }

        void doLowMemActions(bool allowExpensive=false);
        
        bool allowNewWebAppLaunch();

        static void dropBufferCaches();

private:

        MemoryWatcher();
        ~MemoryWatcher();

        bool timerTicked();
        int getCurrentRssUsage() const;

    void adjustOomScore();

#if defined(HAS_MEMCHUTE)
    static void memchuteCallback(MemchuteThreshold threshold);
#endif

public:

        Signal<MemState> signalMemoryStateChanged;
        
private:

        Timer<MemoryWatcher> m_timer;
        int m_currRssUsage;

        int m_timeAtLastLowMemAction;
        int m_timeAtLastExpensiveLowMemAction;

        static const int kFileNameLen = 128;
        char m_fileName[kFileNameLen];

        MemState m_state;
        MemState m_lastNotifiedState;
        

#if defined(HAS_MEMCHUTE)
        int m_memchuteCriticalThreshold;
        MemchuteWatcher* m_memWatch;
#endif  

};

#endif /* MEMORYWATCHER_H */