tdf#119458 fix sw background Idle state handling

Starting the SwDocIdle in StartIdeling() just reintroduces the
bug fixed in commit 401cba4c ("tdf#116370 cleanup Writer idle
job handing"), so trading one bug for the other.

For the real solution we have to handle two states:
1. The SwDocIdle being active
2. The SwDocIdle being blocked

For the first state we can just use the active state of the Idle
itself. Since it's not a AutoIdle, it will be turned of, if
invoked. Either some Idle handler will want to be run it again or
some other thread might start it again, if needed.
Since we're now tracking the wanted Idle state via the active task
flag, we can drop the explicit mbStartIdleTimer handling.

As a result of the first change, we can't stop the Idle anymore
when blocking it. But the Idle itself checks its ready state via
IsDocIdle() in its UpdateMinPeriod function, so we have to add
the blocking state to IsDocIdle().

Change-Id: I33017a8e07208a6a3bce761cc899ac3ca944cd61
Reviewed-on: https://gerrit.libreoffice.org/59586
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

sw/inc/IDocumentTimerAccess.hxx

@@ -21,7 +21,7 @@
 #define INCLUDED_SW_INC_IDOCUMENTTIMERACCESS_HXX
 
 /**
- * Handle the background job of the Writer document.
+ * Handle the background jobs of a Writer document.
  *
  * Initially it's disabled and unblocked.
  *
@@ -34,7 +34,9 @@ class IDocumentTimerAccess
 {
 public:
     /**
-     * Start the idle job depending on the block count.
+     * Start the idle task.
+     *
+     * Depends on the block count and various document states.
      */
     virtual void StartIdling() = 0;
 
@@ -47,13 +49,14 @@ public:
      * Increment block count.
      *
      * Prevents further background idle processing.
+     * This doesn't guarantee the Idle task is not currently running!
      */
     virtual void BlockIdling() = 0;
 
     /**
      * Decrement block count.
      *
-     * May start the idle job.
+     * May re-start the idle task, if active.
      */
     virtual void UnblockIdling() = 0;
 

sw/source/core/doc/DocumentTimerManager.cxx

@@ -38,46 +38,39 @@ namespace sw
 {
 
 DocumentTimerManager::DocumentTimerManager( SwDoc& i_rSwdoc ) : m_rDoc( i_rSwdoc ),
-                                                                mbStartIdleTimer( false ),
-                                                                mIdleBlockCount( 0 ),
-                                                                maDocIdle( i_rSwdoc )
+                                                                m_nIdleBlockCount( 0 ),
+                                                                m_aDocIdle( i_rSwdoc )
 {
-    maDocIdle.SetPriority( TaskPriority::LOWEST );
-    maDocIdle.SetInvokeHandler( LINK( this, DocumentTimerManager, DoIdleJobs) );
-    maDocIdle.SetDebugName( "sw::DocumentTimerManager maDocIdle" );
+    m_aDocIdle.SetPriority(TaskPriority::LOWEST);
+    m_aDocIdle.SetInvokeHandler(LINK( this, DocumentTimerManager, DoIdleJobs));
+    m_aDocIdle.SetDebugName("sw::DocumentTimerManager m_aDocIdle");
 }
 
 void DocumentTimerManager::StartIdling()
 {
-    if( !mIdleBlockCount )
-    {
-        mbStartIdleTimer = false;
-        maDocIdle.Start();
-    }
-    else
-        mbStartIdleTimer = true;
+    if (!m_aDocIdle.IsActive())
+        m_aDocIdle.Start();
 }
 
 void DocumentTimerManager::StopIdling()
 {
-    mbStartIdleTimer = false;
-    maDocIdle.Stop();
+    m_aDocIdle.Stop();
 }
 
 void DocumentTimerManager::BlockIdling()
 {
-    maDocIdle.Stop();
-    ++mIdleBlockCount;
+    assert(SAL_MAX_UINT32 != m_nIdleBlockCount);
+    ++m_nIdleBlockCount;
 }
 
 void DocumentTimerManager::UnblockIdling()
 {
-    --mIdleBlockCount;
-    if( !mIdleBlockCount && mbStartIdleTimer && !maDocIdle.IsActive() )
-    {
-        mbStartIdleTimer = false;
-        maDocIdle.Start();
-    }
+    assert(0 != m_nIdleBlockCount);
+    --m_nIdleBlockCount;
+
+    // kick the active idle, if it's not anymore blocked by IsDocIdle()
+    if (m_aDocIdle.IsActive() && IsDocIdle())
+        m_aDocIdle.Start();
 }
 
 DocumentTimerManager::IdleJob DocumentTimerManager::GetNextIdleJob() const

sw/source/core/inc/DocumentTimerManager.hxx

@@ -66,14 +66,13 @@ private:
 
     SwDoc& m_rDoc;
 
-    bool mbStartIdleTimer; //< idle timer mode start/stop
-    sal_Int32 mIdleBlockCount;
-    SwDocIdle maDocIdle;
+    sal_uInt32 m_nIdleBlockCount; ///< Don't run the Idle, if > 0
+    SwDocIdle m_aDocIdle;
 };
 
 inline bool DocumentTimerManager::IsDocIdle() const
 {
-    return( GetNextIdleJob() != IdleJob::Busy );
+    return ((0 == m_nIdleBlockCount) && (GetNextIdleJob() != IdleJob::Busy));
 }
 
 }