Use a proxy task for field calculator

src/app/qgsattributetabledialog.cpp

@@ -53,6 +53,8 @@
 #include "qgsgui.h"
 #include "qgsclipboard.h"
 #include "qgsfeaturestore.h"
+#include "qgsguiutils.h"
+#include "qgsproxyprogresstask.h"
 
 QgsExpressionContext QgsAttributeTableDialog::createExpressionContext() const
 {
@@ -503,10 +505,6 @@ void QgsAttributeTableDialog::formFilterSet( const QString &filter, QgsAttribute
 
 void QgsAttributeTableDialog::runFieldCalculation( QgsVectorLayer *layer, const QString &fieldName, const QString &expression, const QgsFeatureIds &filteredIds )
 {
-  QApplication::setOverrideCursor( Qt::WaitCursor );
-
-  mLayer->beginEditCommand( QStringLiteral( "Field calculator" ) );
-
   int fieldindex = layer->fields().indexFromName( fieldName );
   if ( fieldindex < 0 )
   {
@@ -516,6 +514,9 @@ void QgsAttributeTableDialog::runFieldCalculation( QgsVectorLayer *layer, const
     return;
   }
 
+  QgsTemporaryCursorOverride cursorOverride( Qt::WaitCursor );
+  mLayer->beginEditCommand( QStringLiteral( "Field calculator" ) );
+
   bool calculationSuccess = true;
   QString error;
 
@@ -542,6 +543,12 @@ void QgsAttributeTableDialog::runFieldCalculation( QgsVectorLayer *layer, const
 
   //go through all the features and change the new attributes
   QgsFeatureIterator fit = layer->getFeatures( request );
+
+  std::unique_ptr< QgsScopedProxyProgressTask > task = qgis::make_unique< QgsScopedProxyProgressTask >( tr( "Calculating field" ) );
+
+  long long count = !filteredIds.isEmpty() ? filteredIds.size() : layer->featureCount();
+  long long i = 0;
+
   QgsFeature feature;
   while ( fit.nextFeature( feature ) )
   {
@@ -550,6 +557,9 @@ void QgsAttributeTableDialog::runFieldCalculation( QgsVectorLayer *layer, const
       continue;
     }
 
+    i++;
+    task->setProgress( i / static_cast< double >( count ) * 100 );
+
     context.setFeature( feature );
     context.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "row_number" ), rownum, true ) );
 
@@ -571,7 +581,8 @@ void QgsAttributeTableDialog::runFieldCalculation( QgsVectorLayer *layer, const
     rownum++;
   }
 
-  QApplication::restoreOverrideCursor();
+  cursorOverride.release();
+  task.reset();
 
   if ( !calculationSuccess )
   {

src/app/qgsfieldcalculator.cpp

@@ -27,6 +27,7 @@
 #include "qgssettings.h"
 #include "qgsgui.h"
 #include "qgsguiutils.h"
+#include "qgsproxyprogresstask.h"
 
 #include <QMessageBox>
 
@@ -289,8 +290,15 @@ void QgsFieldCalculator::accept()
       req.setFilterFids( mVectorLayer->selectedFeatureIds() );
     }
     QgsFeatureIterator fit = mVectorLayer->getFeatures( req );
+
+    std::unique_ptr< QgsScopedProxyProgressTask > task = qgis::make_unique< QgsScopedProxyProgressTask >( tr( "Calculating field" ) );
+    long long count = mOnlyUpdateSelectedCheckBox->isChecked() ? mVectorLayer->selectedFeatureCount() : mVectorLayer->featureCount();
+    long long i = 0;
     while ( fit.nextFeature( feature ) )
     {
+      i++;
+      task->setProgress( i / static_cast< double >( count ) * 100 );
+
       expContext.setFeature( feature );
       expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "row_number" ), rownum, true ) );
 
@@ -323,6 +331,7 @@ void QgsFieldCalculator::accept()
     if ( !calculationSuccess )
     {
       cursorOverride.release();
+      task.reset();
       QMessageBox::critical( nullptr, tr( "Evaluation Error" ), tr( "An error occurred while evaluating the calculation string:\n%1" ).arg( error ) );
       mVectorLayer->destroyEditCommand();
       return;