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Diffstat (limited to 'include/vcl/TaskStopwatch.hxx')
-rw-r--r-- | include/vcl/TaskStopwatch.hxx | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/include/vcl/TaskStopwatch.hxx b/include/vcl/TaskStopwatch.hxx new file mode 100644 index 0000000000..b27b3a316a --- /dev/null +++ b/include/vcl/TaskStopwatch.hxx @@ -0,0 +1,117 @@ +/* -*- 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() + { + sal_uInt64 nCurTicks = tools::Time::GetSystemTicks(); + // handle system ticks wrap as exceeded time slice + if (nCurTicks < m_nStartTicks) + return false; + + if (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; + + 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 another iteration will probably pass in the time slot + **/ + bool continueIter() { return nextIter(); } + + /** + * 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: */ |