Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/include/vcl/TaskStopwatch.hxx b/include/vcl/TaskStopwatch.hxx
new file mode 100644
index 000000000..b27b3a316
--- /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: */