TaskStopwatch.hxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
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 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#ifndef INCLUDED_VCL_TASK_STOPWATCH_HXX
#define INCLUDED_VCL_TASK_STOPWATCH_HXX

#include <tools/time.hxx>
#include <vcl/dllapi.h>
#include <vcl/inputtypes.hxx>
#include <vcl/svapp.hxx>

class VCL_DLLPUBLIC TaskStopwatch
{
    static constexpr VclInputFlags eDefaultInputStop = VCL_INPUT_ANY & ~VclInputFlags::TIMER;
    static constexpr unsigned int nDefaultTimeSlice = 50;
    static unsigned int m_nTimeSlice;

    sal_uInt64 m_nStartTicks;
    sal_uInt64 m_nIterStartTicks;
    bool m_bConsiderLastIterTime;
    VclInputFlags m_eInputStop;

    bool nextIter(bool bQueryOnly)
    {
        sal_uInt64 nCurTicks = tools::Time::GetSystemTicks();
        // handle system ticks wrap as exceeded time slice
        if (nCurTicks < m_nStartTicks)
            return false;

        if (!bQueryOnly && m_bConsiderLastIterTime)
        {
            // based on the last iter runtime, we don't expect to finish in time
            // m_nTimeSlice < (nCurTicks - m_nStartTicks) + (nCurTicks - m_nIterStartTicks)
            if (m_nTimeSlice < 2 * nCurTicks - m_nIterStartTicks - m_nStartTicks)
                return false;
        }
        // time slice exceeded
        else if (m_nTimeSlice < nCurTicks - m_nStartTicks)
            return false;

        if (!bQueryOnly)
            m_nIterStartTicks = nCurTicks;

        return !Application::AnyInput(m_eInputStop);
    }

public:
    TaskStopwatch(bool bConciderLastIterTime = true)
        : m_nStartTicks(tools::Time::GetSystemTicks())
        , m_nIterStartTicks(m_nStartTicks)
        , m_bConsiderLastIterTime(bConciderLastIterTime)
        , m_eInputStop(eDefaultInputStop)
    {
    }

    bool exceededRuntime() { return !nextIter(true); }

    bool continueIter() { return nextIter(false); }

    void reset()
    {
        m_nStartTicks = tools::Time::GetSystemTicks();
        m_nIterStartTicks = m_nStartTicks;
    }

    void setInputStop(VclInputFlags eInputStop = eDefaultInputStop) { m_eInputStop = eInputStop; }
    VclInputFlags inputStop() const { return m_eInputStop; }

    static unsigned int timeSlice() { return m_nTimeSlice; }
    static void setTimeSlice(unsigned int nTimeSlice) { m_nTimeSlice = nTimeSlice; }
};

#endif // INCLUDED_VCL_TASK_STOPWATCH_HXX

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