Prevent tasks from spamming progress reports

nyalldawson · nyalldawson · commit 21c5eaf9bea9 · 2018-05-03T11:23:23.000+10:00
Doing so grinds the QGIS to a halt, yet often progress reports are being sent every feature (which results in thousands of 0.00001 progress increment reports for large layers!!) (cherry-picked from 8961ac4)
diff --git a/src/core/qgstaskmanager.cpp b/src/core/qgstaskmanager.cpp
@@ -212,8 +212,11 @@ void QgsTask::setProgress( double progress )
     progress = ( progress + totalProgress ) / ( mSubTasks.count() + 1 );
   }
 
+  // avoid flooding with too many events
+  if ( static_cast< int >( mTotalProgress  * 10 ) != static_cast< int >( progress * 10 ) )
+    emit progressChanged( progress );
+
   mTotalProgress = progress;
-  emit progressChanged( mTotalProgress );
 }
 
 void QgsTask::completed()

Original file line number	Diff line number	Diff line change
`@@ -212,8 +212,11 @@ void QgsTask::setProgress( double progress )`
`212`	`212`	`progress = ( progress + totalProgress ) / ( mSubTasks.count() + 1 );`
`213`	`213`	`}`
`214`	`214`
	`215`	`+ // avoid flooding with too many events`
	`216`	`+ if ( static_cast< int >( mTotalProgress * 10 ) != static_cast< int >( progress * 10 ) )`
	`217`	`+ emit progressChanged( progress );`
	`218`	`+`
`215`	`219`	`mTotalProgress = progress;`
`216`		`- emit progressChanged( mTotalProgress );`
`217`	`220`	`}`
`218`	`221`
`219`	`222`	`void QgsTask::completed()`