tdf#119458 just wakeup Scheduler on active Idle

So this almost returns the code to the original state, before I
started fixing tdf#116370... a long way. This introduces the new
Scheduler::Wakeup() function, which will just queue a Scheduler
event in the System event queue unconditionally.

This should prevent fdo#73165, which I couldn't reproduce, but
just to be sure.

More importantly this patch resets the m_bStartOnUnblock when
the Idle job actually runs. This run should already determinates
if more Idle work needs to be done, and others can still call
BeginIdling() to ensure further processing.

This also drops the IsBusyDoc() test from UnblockIdling(). We
can't really know, if the document is still busy when the
Scheduler is finally running, be it by the system timer or
Application::Reschedule().

Change-Id: I6cc4a3c48dcaf62b6985c7bc1c95c96697443f3b
Reviewed-on: https://gerrit.libreoffice.org/59730
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

include/vcl/scheduler.hxx

@@ -65,6 +65,18 @@ public:
      */
     static void       ProcessEventsToIdle();
 
+    /**
+     * Wakes up the scheduler
+     *
+     * This doesn't handle any events! It just ensures the Scheduler is run as
+     * soon as possible by forcing the Scheduler timer to fire.
+     *
+     * Can be used for complex UpdateMinPeriod function, where the task is
+     * actually active but not ready and we want to skip the Task::Start()
+     * queue append for faster reaction.
+     */
+    static void       Wakeup();
+
     /// Control the deterministic mode.  In this mode, two subsequent runs of
     /// LibreOffice fire about the same amount idles.
     static void       SetDeterministicMode(bool bDeterministic);

sw/source/core/doc/DocumentTimerManager.cxx

@@ -33,6 +33,7 @@
 #include <docsh.hxx>
 #include <docfld.hxx>
 #include <fldbas.hxx>
+#include <vcl/scheduler.hxx>
 
 namespace sw
 {
@@ -49,10 +50,14 @@ DocumentTimerManager::DocumentTimerManager( SwDoc& i_rSwdoc ) : m_rDoc( i_rSwdoc
 
 void DocumentTimerManager::StartIdling()
 {
-    if (m_nIdleBlockCount > 0)
-        m_bStartOnUnblock = true;
-    else if (!m_aDocIdle.IsActive())
-        m_aDocIdle.Start();
+    m_bStartOnUnblock = true;
+    if (0 == m_nIdleBlockCount)
+    {
+        if (!m_aDocIdle.IsActive())
+            m_aDocIdle.Start();
+        else
+            Scheduler::Wakeup();
+    }
 }
 
 void DocumentTimerManager::StopIdling()
@@ -64,11 +69,6 @@ void DocumentTimerManager::StopIdling()
 void DocumentTimerManager::BlockIdling()
 {
     assert(SAL_MAX_UINT32 != m_nIdleBlockCount);
-    if (0 == m_nIdleBlockCount)
-    {
-        assert(!m_bStartOnUnblock);
-        m_bStartOnUnblock = false;
-    }
     ++m_nIdleBlockCount;
 }
 
@@ -79,10 +79,10 @@ void DocumentTimerManager::UnblockIdling()
 
     if ((0 == m_nIdleBlockCount) && m_bStartOnUnblock)
     {
-        m_bStartOnUnblock = false;
-        // kick the active idle, if it's not anymore blocked by IsDocIdle()
-        if (IsDocIdle())
+        if (!m_aDocIdle.IsActive())
             m_aDocIdle.Start();
+        else
+            Scheduler::Wakeup();
     }
 }
 
@@ -137,6 +137,7 @@ IMPL_LINK_NOARG( DocumentTimerManager, DoIdleJobs, Timer*, void )
         pModLogFile = new ::rtl::Logfile( "First DoIdleJobs" );
 #endif
     BlockIdling();
+    StopIdling();
 
     IdleJob eJob = GetNextIdleJob();
 

vcl/source/app/scheduler.cxx

@@ -506,6 +506,11 @@ next_entry:
     return !!pMostUrgent;
 }
 
+void Scheduler::Wakeup()
+{
+    Scheduler::ImplStartTimer( 0, false, tools::Time::GetSystemTicks() );
+}
+
 void Task::StartTimer( sal_uInt64 nMS )
 {
     Scheduler::ImplStartTimer( nMS, false, tools::Time::GetSystemTicks() );