move getValues, getDoubleValues to vector layer utils source file

Author: nirvn

python/core/qgsvectorlayer.sip.in

@@ -2013,40 +2013,6 @@ Calculates an aggregated value from the layer's features.
 :return: calculated aggregate value
 
 .. versionadded:: 2.16
-%End
-
-    QList< QVariant > getValues( const QString &fieldOrExpression, bool &ok, bool selectedOnly = false, QgsFeedback *feedback = 0 ) const;
-%Docstring
-Fetches all values from a specified field name or expression.
-
-:param fieldOrExpression: field name or an expression string
-:param ok: will be set to false if field or expression is invalid, otherwise true
-:param selectedOnly: set to true to get values from selected features only
-:param feedback: optional feedback object to allow cancelation
-
-:return: list of fetched values
-
-.. versionadded:: 2.9
-
-.. seealso:: :py:func:`getDoubleValues`
-%End
-
-    QList< double > getDoubleValues( const QString &fieldOrExpression, bool &ok, bool selectedOnly = false, int *nullCount = 0, QgsFeedback *feedback = 0 ) const;
-%Docstring
-Fetches all double values from a specified field name or expression. Null values or
-invalid expression results are skipped.
-
-:param fieldOrExpression: field name or an expression string evaluating to a double value
-:param ok: will be set to false if field or expression is invalid, otherwise true
-:param selectedOnly: set to true to get values from selected features only
-:param nullCount: optional pointer to integer to store number of null values encountered in
-:param feedback: optional feedback object to allow cancelation
-
-:return: list of fetched values
-
-.. versionadded:: 2.9
-
-.. seealso:: :py:func:`getValues`
 %End
 
     void setFeatureBlendMode( QPainter::CompositionMode blendMode );

python/core/qgsvectorlayerutils.sip.in

@@ -57,6 +57,56 @@ Returns the duplicated features in the given layer
 
     };
 
+    static QgsFeatureIterator getValuesIterator( const QgsVectorLayer *layer, const QString &fieldOrExpression, bool &ok, bool selectedOnly );
+%Docstring
+Create a feature iterator for a specified field name or expression.
+
+:param layer: vector layer to retrieve values from
+:param fieldOrExpression: field name or an expression string
+:param ok: will be set to false if field or expression is invalid, otherwise true
+:param selectedOnly: set to true to get values from selected features only
+
+:return: feature iterator
+
+.. versionadded:: 3.0
+%End
+
+    static QList< QVariant > getValues( const QgsVectorLayer *layer, const QString &fieldOrExpression, bool &ok, bool selectedOnly = false, QgsFeedback *feedback = 0 );
+%Docstring
+Fetches all values from a specified field name or expression.
+
+:param layer: vector layer to retrieve values from
+:param fieldOrExpression: field name or an expression string
+:param ok: will be set to false if field or expression is invalid, otherwise true
+:param selectedOnly: set to true to get values from selected features only
+:param feedback: optional feedback object to allow cancelation
+
+:return: list of fetched values
+
+.. versionadded:: 3.0
+
+.. seealso:: :py:func:`getDoubleValues`
+%End
+
+    static QList< double > getDoubleValues( const QgsVectorLayer *layer, const QString &fieldOrExpression, bool &ok, bool selectedOnly = false, int *nullCount = 0, QgsFeedback *feedback = 0 );
+%Docstring
+Fetches all double values from a specified field name or expression. Null values or
+invalid expression results are skipped.
+
+:param layer: vector layer to retrieve values from
+:param fieldOrExpression: field name or an expression string evaluating to a double value
+:param ok: will be set to false if field or expression is invalid, otherwise true
+:param selectedOnly: set to true to get values from selected features only
+:param nullCount: optional pointer to integer to store number of null values encountered in
+:param feedback: optional feedback object to allow cancelation
+
+:return: list of fetched values
+
+.. versionadded:: 3.0
+
+.. seealso:: :py:func:`getValues`
+%End
+
     static bool valueExists( const QgsVectorLayer *layer, int fieldIndex, const QVariant &value, const QgsFeatureIds &ignoreIds = QgsFeatureIds() );
 %Docstring
 Returns true if the specified value already exists within a field. This method can be used to test for uniqueness

src/app/qgsstatisticalsummarydockwidget.h

@@ -24,6 +24,7 @@
 #include "qgsdockwidget.h"
 #include "qgsfeedback.h"
 #include "qgsvectorlayer.h"
+#include "qgsvectorlayerutils.h"
 #include "qgis_app.h"
 
 class QMenu;
@@ -60,7 +61,7 @@ class QgsStatisticsValueGatherer: public QThread
       connect( mFeedback, &QgsFeedback::progressChanged, this, &QgsStatisticsValueGatherer::progressChanged );
 
       bool ok;
-      mValues = mLayer->getValues( mExpression, ok, mSelectedOnly, mFeedback );
+      mValues = QgsVectorLayerUtils::getValues( mLayer, mExpression, ok, mSelectedOnly, mFeedback );
       if ( !ok )
       {
         mWasCanceled = true;

src/core/qgshistogram.cpp

@@ -19,6 +19,7 @@
 
 #include "qgsstatisticalsummary.h"
 #include "qgsvectorlayer.h"
+#include "qgsvectorlayerutils.h"
 
 void QgsHistogram::prepareValues()
 {
@@ -45,7 +46,7 @@ bool QgsHistogram::setValues( const QgsVectorLayer *layer, const QString &fieldO
     return false;
 
   bool ok;
-  mValues = layer->getDoubleValues( fieldOrExpression, ok, false, nullptr, feedback );
+  mValues = QgsVectorLayerUtils::getDoubleValues( layer, fieldOrExpression, ok, false, nullptr, feedback );
   if ( !ok )
     return false;
 

src/core/qgsvectorlayer.cpp

@@ -3655,106 +3655,6 @@ QVariant QgsVectorLayer::aggregate( QgsAggregateCalculator::Aggregate aggregate,
   return c.calculate( aggregate, fieldOrExpression, context, ok );
 }
 
-QList<QVariant> QgsVectorLayer::getValues( const QString &fieldOrExpression, bool &ok, bool selectedOnly, QgsFeedback *feedback ) const
-{
-  QList<QVariant> values;
-
-  std::unique_ptr<QgsExpression> expression;
-  QgsExpressionContext context;
-
-  int attrNum = mFields.lookupField( fieldOrExpression );
-
-  if ( attrNum == -1 )
-  {
-    // try to use expression
-    expression.reset( new QgsExpression( fieldOrExpression ) );
-    context.appendScopes( QgsExpressionContextUtils::globalProjectLayerScopes( this ) );
-
-    if ( expression->hasParserError() || !expression->prepare( &context ) )
-    {
-      ok = false;
-      return values;
-    }
-  }
-
-  QgsFeature f;
-  QSet<QString> lst;
-  if ( !expression )
-    lst.insert( fieldOrExpression );
-  else
-    lst = expression->referencedColumns();
-
-  QgsFeatureRequest request = QgsFeatureRequest()
-                              .setFlags( ( expression && expression->needsGeometry() ) ?
-                                         QgsFeatureRequest::NoFlags :
-                                         QgsFeatureRequest::NoGeometry )
-                              .setSubsetOfAttributes( lst, fields() );
-
-  QgsFeatureIterator fit;
-  if ( !selectedOnly )
-  {
-    fit = getFeatures( request );
-  }
-  else
-  {
-    fit = getSelectedFeatures( request );
-  }
-
-  // create list of non-null attribute values
-  while ( fit.nextFeature( f ) )
-  {
-    if ( expression )
-    {
-      context.setFeature( f );
-      QVariant v = expression->evaluate( &context );
-      values << v;
-    }
-    else
-    {
-      values << f.attribute( attrNum );
-    }
-    if ( feedback && feedback->isCanceled() )
-    {
-      ok = false;
-      return values;
-    }
-  }
-  ok = true;
-  return values;
-}
-
-QList<double> QgsVectorLayer::getDoubleValues( const QString &fieldOrExpression, bool &ok, bool selectedOnly, int *nullCount, QgsFeedback *feedback ) const
-{
-  QList<double> values;
-
-  if ( nullCount )
-    *nullCount = 0;
-
-  QList<QVariant> variantValues = getValues( fieldOrExpression, ok, selectedOnly, feedback );
-  if ( !ok )
-    return values;
-
-  bool convertOk;
-  Q_FOREACH ( const QVariant &value, variantValues )
-  {
-    double val = value.toDouble( &convertOk );
-    if ( convertOk )
-      values << val;
-    else if ( value.isNull() )
-    {
-      if ( nullCount )
-        *nullCount += 1;
-    }
-    if ( feedback && feedback->isCanceled() )
-    {
-      ok = false;
-      return values;
-    }
-  }
-  ok = true;
-  return values;
-}
-
 void QgsVectorLayer::setFeatureBlendMode( QPainter::CompositionMode featureBlendMode )
 {
   mFeatureBlendMode = featureBlendMode;

src/core/qgsvectorlayer.h

@@ -1821,32 +1821,6 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
                         QgsExpressionContext *context = nullptr,
                         bool *ok = nullptr ) const;
 
-    /**
-     * Fetches all values from a specified field name or expression.
-     * \param fieldOrExpression field name or an expression string
-     * \param ok will be set to false if field or expression is invalid, otherwise true
-     * \param selectedOnly set to true to get values from selected features only
-     * \param feedback optional feedback object to allow cancelation
-     * \returns list of fetched values
-     * \since QGIS 2.9
-     * \see getDoubleValues
-     */
-    QList< QVariant > getValues( const QString &fieldOrExpression, bool &ok, bool selectedOnly = false, QgsFeedback *feedback = nullptr ) const;
-
-    /**
-     * Fetches all double values from a specified field name or expression. Null values or
-     * invalid expression results are skipped.
-     * \param fieldOrExpression field name or an expression string evaluating to a double value
-     * \param ok will be set to false if field or expression is invalid, otherwise true
-     * \param selectedOnly set to true to get values from selected features only
-     * \param nullCount optional pointer to integer to store number of null values encountered in
-     * \param feedback optional feedback object to allow cancelation
-     * \returns list of fetched values
-     * \since QGIS 2.9
-     * \see getValues
-     */
-    QList< double > getDoubleValues( const QString &fieldOrExpression, bool &ok, bool selectedOnly = false, int *nullCount = nullptr, QgsFeedback *feedback = nullptr ) const;
-
     //! Set the blending mode used for rendering each feature
     void setFeatureBlendMode( QPainter::CompositionMode blendMode );
     //! Returns the current blending mode for features