tdf#100092: Deterministic scheduling to prevent unpredictable behavior.

Low priority idles can fire more or less randomly, and consequently two
consequent runs of LibreOffice differ in the amount of the idles that have
been performed during an operation.

This commit adds a possibility to turn on a 'deterministic mode' where two
subsequent runs of LibreOffice trigger about the same amount of events when
they perform the same set of operations.

Change-Id: I92566ef4eee20e7d604cfd48f01c4df30c77e653

1 files changed, 8 insertions, 1 deletions

diff --git a/include/vcl/scheduler.hxx b/include/vcl/scheduler.hxx
index 760c228b174e..3abd37d6976e 100644
--- a/include/vcl/scheduler.hxx
+++ b/include/vcl/scheduler.hxx
@@ -47,6 +47,7 @@ protected:
 
     // These should be constexpr static, when supported.
     static const sal_uInt64 ImmediateTimeoutMs = 1;
+    static const sal_uInt64 InfiniteTimeoutMs = 1000 * 60 * 60 * 24; // 1 day
 
     static void ImplStartTimer(sal_uInt64 nMS, bool bForce = false);
 
@@ -84,7 +85,7 @@ public:
     Scheduler&      operator=( const Scheduler& rScheduler );
     static void ImplDeInitScheduler();
 
-    // Process one pending Timer with highhest priority
+    /// Process one pending Timer with highhest priority
     static void CallbackTaskScheduling( bool ignore );
     /// Calculate minimum timeout - and return its value.
     static sal_uInt64 CalculateMinimumTimeout( bool &bHasActiveIdles );
@@ -92,6 +93,12 @@ public:
     static bool       ProcessTaskScheduling( bool bTimerOnly );
     /// Process all events until we are idle
     static void       ProcessEventsToIdle();
+
+    /// Control the deterministic mode.  In this mode, two subsequent runs of
+    /// LibreOffice fire about the same amount idles.
+    static void SetDeterministicMode(bool bDeterministic);
+    /// Return the current state of deterministic mode.
+    static bool GetDeterministicMode();
 };
 
 #endif // INCLUDED_VCL_SCHEDULER_HXX