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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* 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>
/**
* Helper class primary used to track time of long running iterating tasks.
*
* Normally it should be sufficient to instantiate the watch object before
* starting the iteration and query continueIter() at the end of each.
*
* Called Stopwatch, because there is already a Timer class in the Scheduler.
*
* TODO: merge into the general Scheduler, so this can also be used to track
* Task runtimes in a more general way.
* TODO: handle fast iterations, where continueIter is called multiple times
* per tick, by counting the iterations per tick and use that for approximation.
**/
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:
/**
* Per default the watch considers the last iter time when asking for an
* other iteration, so considers Scheduler::acceptableTaskTime as a
* maximum value.
*
* If you already know your iter time vary in a large range, consider
* setting bConciderLastIterTime to false, so Scheduler::acceptableTaskTime
* will be used as a minimum time slot.
**/
TaskStopwatch(bool bConciderLastIterTime = true)
: m_nStartTicks(tools::Time::GetSystemTicks())
, m_nIterStartTicks(m_nStartTicks)
, m_bConsiderLastIterTime(bConciderLastIterTime)
, m_eInputStop(eDefaultInputStop)
{
}
/**
* Returns true, if the time slot is already exceeded
**/
bool exceededRuntime() { return !nextIter(true); }
/**
* Returns true, if another iteration will probably pass in the time slot
**/
bool continueIter() { return nextIter(false); }
/**
* Reset the stopwatch
**/
void reset()
{
m_nStartTicks = tools::Time::GetSystemTicks();
m_nIterStartTicks = m_nStartTicks;
}
/**
* Sets the input events, which should also "exceed" the stopwatch.
*
* Per default this ignores the VclInputFlags::TIMER.
*/
void setInputStop(VclInputFlags eInputStop = eDefaultInputStop) { m_eInputStop = eInputStop; }
VclInputFlags inputStop() const { return m_eInputStop; }
/**
* Sets the time considered the acceptable maximum for a task to run
*
* This is an orientation for long time background jobs to yield to
* the scheduler, so Idle task don't starve each other too much.
**/
static unsigned int timeSlice() { return m_nTimeSlice; }
static void setTimeSlice(unsigned int nTimeSlice) { m_nTimeSlice = nTimeSlice; }
};
#endif // INCLUDED_VCL_TASK_STOPWATCH_HXX
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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