Merge pull request #2600 from m-kuhn/orderby-renderer

Allow definition of feature rendering order

python/core/qgsfeaturerequest.sip

@@ -78,6 +78,42 @@ class QgsFeatureRequest
 
     };
 
+    class OrderBy
+    {
+      public:
+        OrderBy();
+
+        OrderBy( const QList<QgsFeatureRequest::OrderByClause>& other );
+
+        /**
+         * Get a copy as a list of OrderByClauses
+         *
+         * This is only required in python where the inheritance
+         * is not properly propagated and this makes it usable.
+         */
+        QList<QgsFeatureRequest::OrderByClause> list() const;
+
+        /**
+         * Serialize to XML
+         */
+        void save( QDomElement& elem ) const;
+
+        /**
+         * Deserialize from XML
+         */
+        void load( const QDomElement& elem );
+
+        /**
+         * Returns a set of used attributes
+         */
+        QSet<QString> usedAttributes() const;
+
+        /**
+         * Dumps the content to an SQL equivalent syntax
+         */
+        QString dump() const;
+    };
+
     /**
      * A special attribute that if set matches all attributes
      */
@@ -175,12 +211,12 @@ class QgsFeatureRequest
     /**
      * Return a list of order by clauses specified for this feature request.
      */
-    QList<QgsFeatureRequest::OrderByClause> orderBys() const;
+    QgsFeatureRequest::OrderBy orderBy() const;
 
     /**
      * Set a list of order by clauses.
      */
-    void setOrderBys(const QList<QgsFeatureRequest::OrderByClause>& orderBys );
+    QgsFeatureRequest& setOrderBy(const QgsFeatureRequest::OrderBy& orderBy );
 
     /** Set the maximum number of features to request.
      * @param limit maximum number of features, or -1 to request all features.

python/core/symbology-ng/qgsrendererv2.sip

@@ -312,6 +312,18 @@ class QgsFeatureRendererV2
      */
     void setForceRasterRender( bool forceRaster );
 
+    /**
+     * Get the order in which features shall be processed by this renderer.
+     * @note added in QGIS 2.14
+     */
+    QgsFeatureRequest::OrderBy orderBy() const;
+
+    /**
+     * Define the order in which features shall be processed by this renderer.
+     * @note added in QGIS 2.14
+     */
+    void setOrderBy( const QgsFeatureRequest::OrderBy& orderBy );
+
   protected:
     QgsFeatureRendererV2( const QString& type );
 

python/gui/qgsorderbydialog.sip

@@ -0,0 +1,34 @@
+/***************************************************************************
+ qgsorderbydialog.h
+
+ ---------------------
+ begin                : 20.12.2015
+ copyright            : (C) 2015 by Matthias Kuhn
+ email                : matthias@opengis.ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+class QgsOrderByDialog : QDialog
+{
+%TypeHeaderCode
+#include "qgsorderbydialog.h"
+%End
+  public:
+    QgsOrderByDialog( QgsVectorLayer* layer, QWidget* parent = nullptr );
+
+    /**
+     * Set the order by to manage
+     */
+    void setOrderBys( const QList<QgsFeatureRequest::OrderByClause>& orderBys );
+
+    /**
+     * Get the order by defined in the dialog
+     */
+    QgsFeatureRequest::OrderBy orderBys();
+};

src/core/qgsfeatureiterator.cpp

@@ -120,6 +120,7 @@ class QgsExpressionSorter
 QgsAbstractFeatureIterator::QgsAbstractFeatureIterator( const QgsFeatureRequest& request )
     : mRequest( request )
     , mClosed( false )
+    , mZombie( false )
     , refs( 0 )
     , mFetchedCount( 0 )
     , mGeometrySimplifier( nullptr )
@@ -149,6 +150,12 @@ bool QgsAbstractFeatureIterator::nextFeature( QgsFeature& f )
       ++mFeatureIterator;
       dataOk = true;
     }
+    else
+    {
+      dataOk = false;
+      // even the zombie dies at this point...
+      mZombie = false;
+    }
   }
   else
   {
@@ -213,7 +220,7 @@ void QgsAbstractFeatureIterator::ref()
     prepareSimplification( mRequest.simplifyMethod() );
 
     // Should be called as last preparation step since it possibly will already fetch all features
-    setupOrderBy( mRequest.orderBys() );
+    setupOrderBy( mRequest.orderBy() );
   }
   refs++;
 }
@@ -279,10 +286,12 @@ void QgsAbstractFeatureIterator::setupOrderBy( const QList<QgsFeatureRequest::Or
       mCachedFeatures.append( indexedFeature );
     }
 
-    std::sort( mCachedFeatures.begin(), mCachedFeatures.end(), QgsExpressionSorter( preparedOrderBys ) );
+    qSort( mCachedFeatures.begin(), mCachedFeatures.end(), QgsExpressionSorter( preparedOrderBys ) );
 
     mFeatureIterator = mCachedFeatures.constBegin();
     mUseCachedFeatures = true;
+    // The real iterator is closed, we are only serving cached features
+    mZombie = true;
   }
 }
 

src/core/qgsfeatureiterator.h

@@ -89,7 +89,17 @@ class CORE_EXPORT QgsAbstractFeatureIterator
     /** Set to true, as soon as the iterator is closed. */
     bool mClosed;
 
+    /**
+     * A feature iterator may be closed already but still be serving features from the cache.
+     * This is done when we serve features which have been pre-fetched and the order by has
+     * been locally sorted.
+     * In such a scenario, all resources have been released (mClosed is true) but the deads
+     * are still alive.
+     */
+    bool mZombie;
+
     //! reference counting (to allow seamless copying of QgsFeatureIterator instances)
+    //! TODO QGIS3: make this private
     int refs;
     void ref(); //!< add reference
     void deref(); //!< remove reference, delete if refs == 0
@@ -247,7 +257,7 @@ inline bool QgsFeatureIterator::close()
 
 inline bool QgsFeatureIterator::isClosed() const
 {
-  return mIter ? mIter->mClosed : true;
+  return mIter ? mIter->mClosed && !mIter->mZombie : true;
 }
 
 inline bool operator== ( const QgsFeatureIterator &fi1, const QgsFeatureIterator &fi2 )

src/core/qgsfeaturerequest.cpp

@@ -84,7 +84,7 @@ QgsFeatureRequest& QgsFeatureRequest::operator=( const QgsFeatureRequest & rh )
   mAttrs = rh.mAttrs;
   mSimplifyMethod = rh.mSimplifyMethod;
   mLimit = rh.mLimit;
-  mOrderBys = rh.mOrderBys;
+  mOrderBy = rh.mOrderBy;
   return *this;
 }
 
@@ -144,24 +144,25 @@ QgsFeatureRequest &QgsFeatureRequest::setExpressionContext( const QgsExpressionC
 
 QgsFeatureRequest& QgsFeatureRequest::addOrderBy( const QString& expression, bool ascending )
 {
-  mOrderBys.append( OrderByClause( expression, ascending ) );
+  mOrderBy.append( OrderByClause( expression, ascending ) );
   return *this;
 }
 
 QgsFeatureRequest& QgsFeatureRequest::addOrderBy( const QString& expression, bool ascending, bool nullsfirst )
 {
-  mOrderBys.append( OrderByClause( expression, ascending, nullsfirst ) );
+  mOrderBy.append( OrderByClause( expression, ascending, nullsfirst ) );
   return *this;
 }
 
-QList<QgsFeatureRequest::OrderByClause> QgsFeatureRequest::orderBys() const
+QgsFeatureRequest::OrderBy QgsFeatureRequest::orderBy() const
 {
-  return mOrderBys;
+  return mOrderBy;
 }
 
-void QgsFeatureRequest::setOrderBys( const QList<QgsFeatureRequest::OrderByClause>& orderBys )
+QgsFeatureRequest& QgsFeatureRequest::setOrderBy( const QgsFeatureRequest::OrderBy& orderBy )
 {
-  mOrderBys = orderBys;
+  mOrderBy = orderBy;
+  return *this;
 }
 
 QgsFeatureRequest& QgsFeatureRequest::setLimit( long limit )
@@ -307,7 +308,90 @@ void QgsFeatureRequest::OrderByClause::setNullsFirst( bool nullsFirst )
   mNullsFirst = nullsFirst;
 }
 
+QString QgsFeatureRequest::OrderByClause::dump() const
+{
+  return QString( "%1 %2 %3" )
+         .arg( mExpression.expression() )
+         .arg( mAscending ? "ASC" : "DESC" )
+         .arg( mNullsFirst ? "NULLS FIRST" : "NULLS LAST" );
+}
+
 QgsExpression QgsFeatureRequest::OrderByClause::expression() const
 {
   return mExpression;
 }
+
+QgsFeatureRequest::OrderBy::OrderBy( const QList<QgsFeatureRequest::OrderByClause>& other )
+{
+  Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, other )
+  {
+    append( clause );
+  }
+}
+
+QList<QgsFeatureRequest::OrderByClause> QgsFeatureRequest::OrderBy::list() const
+{
+  return *this;
+}
+
+void QgsFeatureRequest::OrderBy::save( QDomElement& elem ) const
+{
+  QDomDocument doc = elem.ownerDocument();
+  QList<OrderByClause>::ConstIterator it;
+  for ( it = constBegin(); it != constEnd(); ++it )
+  {
+    const OrderByClause& clause = *it;
+    QDomElement clauseElem = doc.createElement( "orderByClause" );
+    clauseElem.setAttribute( "asc", clause.ascending() );
+    clauseElem.setAttribute( "nullsFirst", clause.nullsFirst() );
+    clauseElem.appendChild( doc.createTextNode( clause.expression().expression() ) );
+
+    elem.appendChild( clauseElem );
+  }
+}
+
+void QgsFeatureRequest::OrderBy::load( const QDomElement& elem )
+{
+  clear();
+
+  QDomNodeList clauses = elem.childNodes();
+
+  for ( int i = 0; i < clauses.size(); ++i )
+  {
+    QDomElement clauseElem = clauses.at( i ).toElement();
+    QString expression = clauseElem.text();
+    bool asc = clauseElem.attribute( "asc" ).toInt() != 0;
+    bool nullsFirst  = clauseElem.attribute( "nullsFirst" ).toInt() != 0;
+
+    append( OrderByClause( expression, asc, nullsFirst ) );
+  }
+}
+
+QSet<QString> QgsFeatureRequest::OrderBy::usedAttributes() const
+{
+  QSet<QString> usedAttributes;
+
+  QList<OrderByClause>::ConstIterator it;
+  for ( it = constBegin(); it != constEnd(); ++it )
+  {
+    const OrderByClause& clause = *it;
+
+    usedAttributes.unite( clause.expression().referencedColumns().toSet() );
+  }
+
+  return usedAttributes;
+}
+QString QgsFeatureRequest::OrderBy::dump() const
+{
+  QStringList results;
+
+  QList<OrderByClause>::ConstIterator it;
+  for ( it = constBegin(); it != constEnd(); ++it )
+  {
+    const OrderByClause& clause = *it;
+
+    results << clause.dump();
+  }
+
+  return results.join( ", " );
+}

src/core/qgsfeaturerequest.h

@@ -155,12 +155,67 @@ class CORE_EXPORT QgsFeatureRequest
          */
         void setNullsFirst( bool nullsFirst );
 
+        /**
+         * Dumps the content to an SQL equivalent
+         */
+        QString dump() const;
+
       private:
         QgsExpression mExpression;
         bool mAscending;
         bool mNullsFirst;
     };
 
+    /**
+     * Represents a list of OrderByClauses, with the most important first and the least
+     * important last.
+     *
+     * @note added in QGIS 2.14
+     */
+    class OrderBy : public QList<OrderByClause>
+    {
+      public:
+        /**
+         * Create a new empty order by
+         */
+        OrderBy()
+            : QList<OrderByClause>()
+        {}
+
+        /**
+         * Create a new order by from a list of clauses
+         */
+        OrderBy( const QList<OrderByClause>& other );
+
+        /**
+         * Get a copy as a list of OrderByClauses
+         *
+         * This is only required in python where the inheritance
+         * is not properly propagated and this makes it usable.
+         */
+        QList<OrderByClause> list() const;
+
+        /**
+         * Serialize to XML
+         */
+        void save( QDomElement& elem ) const;
+
+        /**
+         * Deserialize from XML
+         */
+        void load( const QDomElement& elem );
+
+        /**
+         * Returns a set of used attributes
+         */
+        QSet<QString> usedAttributes() const;
+
+        /**
+         * Dumps the content to an SQL equivalent syntax
+         */
+        QString dump() const;
+    };
+
     /**
      * A special attribute that if set matches all attributes
      */
@@ -277,13 +332,17 @@ class CORE_EXPORT QgsFeatureRequest
 
     /**
      * Return a list of order by clauses specified for this feature request.
+     *
+     * @note added in 2.14
      */
-    QList<OrderByClause> orderBys() const;
+    OrderBy orderBy() const;
 
     /**
      * Set a list of order by clauses.
+     *
+     * @note added in 2.14
      */
-    void setOrderBys( const QList<OrderByClause>& orderBys );
+    QgsFeatureRequest& setOrderBy( const OrderBy& orderBy );
 
     /** Set the maximum number of features to request.
      * @param limit maximum number of features, or -1 to request all features.
@@ -346,7 +405,7 @@ class CORE_EXPORT QgsFeatureRequest
     QgsAttributeList mAttrs;
     QgsSimplifyMethod mSimplifyMethod;
     long mLimit;
-    QList<OrderByClause> mOrderBys;
+    OrderBy mOrderBy;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsFeatureRequest::Flags )

src/core/qgsvectorlayerfeatureiterator.cpp

@@ -105,17 +105,30 @@ QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayerFeat
   if ( mProviderRequest.flags() & QgsFeatureRequest::SubsetOfAttributes )
   {
     // prepare list of attributes to match provider fields
-    QgsAttributeList providerSubset;
+    QSet<int> providerSubset;
     QgsAttributeList subset = mProviderRequest.subsetOfAttributes();
     int nPendingFields = mSource->mFields.count();
-    for ( int i = 0; i < subset.count(); ++i )
+    Q_FOREACH ( int attrIndex, subset )
     {
-      int attrIndex = subset[i];
       if ( attrIndex < 0 || attrIndex >= nPendingFields ) continue;
       if ( mSource->mFields.fieldOrigin( attrIndex ) == QgsFields::OriginProvider )
         providerSubset << mSource->mFields.fieldOriginIndex( attrIndex );
     }
-    mProviderRequest.setSubsetOfAttributes( providerSubset );
+
+    // This is done in order to be prepared to do fallback order bys
+    // and be sure we have the required columns.
+    // TODO:
+    // It would be nicer to first check if we can compile the order by
+    // and only modify the subset if we cannot.
+    if ( !mProviderRequest.orderBy().isEmpty() )
+    {
+      Q_FOREACH ( const QString& attr, mProviderRequest.orderBy().usedAttributes() )
+      {
+        providerSubset << mSource->mFields.fieldNameIndex( attr );
+      }
+    }
+
+    mProviderRequest.setSubsetOfAttributes( providerSubset.toList() );
   }
 
   if ( mProviderRequest.filterType() == QgsFeatureRequest::FilterExpression )

src/core/qgsvectorlayerrenderer.cpp

@@ -150,10 +150,13 @@ bool QgsVectorLayerRenderer::render()
   QgsRectangle requestExtent = mContext.extent();
   mRendererV2->modifyRequestExtent( requestExtent, mContext );
 
+  QgsFeatureRequest::OrderBy orderBy = mRendererV2->orderBy();
+
   QgsFeatureRequest featureRequest = QgsFeatureRequest()
                                      .setFilterRect( requestExtent )
                                      .setSubsetOfAttributes( mAttrNames, mFields )
-                                     .setExpressionContext( mContext.expressionContext() );
+                                     .setExpressionContext( mContext.expressionContext() )
+                                     .setOrderBy( orderBy );
 
   const QgsFeatureFilterProvider* featureFilterProvider = mContext.featureFilterProvider();
   if ( featureFilterProvider )

src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp

@@ -498,7 +498,7 @@ QgsCategorizedSymbolRendererV2* QgsCategorizedSymbolRendererV2::clone() const
   r->setUsingSymbolLevels( usingSymbolLevels() );
   r->setSizeScaleField( sizeScaleField() );
 
-  copyPaintEffect( r );
+  copyRendererData( r );
   return r;
 }
 
@@ -761,6 +761,13 @@ QDomElement QgsCategorizedSymbolRendererV2::save( QDomDocument& doc )
   if ( mPaintEffect && !QgsPaintEffectRegistry::isDefaultStack( mPaintEffect ) )
     mPaintEffect->saveProperties( doc, rendererElem );
 
+  if ( !mOrderBy.isEmpty() )
+  {
+    QDomElement orderBy = doc.createElement( "orderby" );
+    mOrderBy.save( orderBy );
+    rendererElem.appendChild( orderBy );
+  }
+
   return rendererElem;
 }
 

src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp

@@ -529,7 +529,7 @@ QgsGraduatedSymbolRendererV2* QgsGraduatedSymbolRendererV2::clone() const
   r->setSizeScaleField( sizeScaleField() );
   r->setLabelFormat( labelFormat() );
   r->setGraduatedMethod( graduatedMethod() );
-  copyPaintEffect( r );
+  copyRendererData( r );
   return r;
 }
 
@@ -1171,6 +1171,13 @@ QDomElement QgsGraduatedSymbolRendererV2::save( QDomDocument& doc )
   if ( mPaintEffect && !QgsPaintEffectRegistry::isDefaultStack( mPaintEffect ) )
     mPaintEffect->saveProperties( doc, rendererElem );
 
+  if ( !mOrderBy.isEmpty() )
+  {
+    QDomElement orderBy = doc.createElement( "orderby" );
+    mOrderBy.save( orderBy );
+    rendererElem.appendChild( orderBy );
+  }
+
   return rendererElem;
 }
 

src/core/symbology-ng/qgsheatmaprenderer.cpp

@@ -297,7 +297,7 @@ QgsHeatmapRenderer* QgsHeatmapRenderer::clone() const
   newRenderer->setMaximumValue( mExplicitMax );
   newRenderer->setRenderQuality( mRenderQuality );
   newRenderer->setWeightExpression( mWeightExpressionString );
-  copyPaintEffect( newRenderer );
+  copyRendererData( newRenderer );
 
   return newRenderer;
 }
@@ -365,6 +365,13 @@ QDomElement QgsHeatmapRenderer::save( QDomDocument& doc )
   if ( mPaintEffect && !QgsPaintEffectRegistry::isDefaultStack( mPaintEffect ) )
     mPaintEffect->saveProperties( doc, rendererElem );
 
+  if ( !mOrderBy.isEmpty() )
+  {
+    QDomElement orderBy = doc.createElement( "orderby" );
+    mOrderBy.save( orderBy );
+    rendererElem.appendChild( orderBy );
+  }
+
   return rendererElem;
 }
 

src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp

@@ -344,7 +344,7 @@ QgsInvertedPolygonRenderer* QgsInvertedPolygonRenderer::clone() const
     newRenderer = new QgsInvertedPolygonRenderer( mSubRenderer.data() );
   }
   newRenderer->setPreprocessingEnabled( preprocessingEnabled() );
-  copyPaintEffect( newRenderer );
+  copyRendererData( newRenderer );
   return newRenderer;
 }
 

src/core/symbology-ng/qgspointdisplacementrenderer.cpp

@@ -80,7 +80,7 @@ QgsPointDisplacementRenderer* QgsPointDisplacementRenderer::clone() const
   {
     r->setCenterSymbol( mCenterSymbol->clone() );
   }
-  copyPaintEffect( r );
+  copyRendererData( r );
   return r;
 }
 

src/core/symbology-ng/qgsrendererv2.cpp

@@ -204,6 +204,15 @@ void QgsFeatureRendererV2::setScaleMethodToSymbol( QgsSymbolV2* symbol, int scal
   }
 }
 
+void QgsFeatureRendererV2::copyRendererData( QgsFeatureRendererV2* destRenderer ) const
+{
+  if ( !destRenderer || !mPaintEffect )
+    return;
+
+  destRenderer->setPaintEffect( mPaintEffect->clone() );
+  destRenderer->mOrderBy = mOrderBy;
+}
+
 void QgsFeatureRendererV2::copyPaintEffect( QgsFeatureRendererV2 *destRenderer ) const
 {
   if ( !destRenderer || !mPaintEffect )
@@ -212,7 +221,6 @@ void QgsFeatureRendererV2::copyPaintEffect( QgsFeatureRendererV2 *destRenderer )
   destRenderer->setPaintEffect( mPaintEffect->clone() );
 }
 
-
 QgsFeatureRendererV2::QgsFeatureRendererV2( const QString& type )
     : mType( type )
     , mUsingSymbolLevels( false )
@@ -331,6 +339,10 @@ QgsFeatureRendererV2* QgsFeatureRendererV2::load( QDomElement& element )
     {
       r->setPaintEffect( QgsPaintEffectRegistry::instance()->createEffect( effectElem ) );
     }
+
+    // restore order by
+    QDomElement orderByElem = element.firstChildElement( "orderby" );
+    r->mOrderBy.load( orderByElem );
   }
   return r;
 }
@@ -344,6 +356,12 @@ QDomElement QgsFeatureRendererV2::save( QDomDocument& doc )
   if ( mPaintEffect && !QgsPaintEffectRegistry::isDefaultStack( mPaintEffect ) )
     mPaintEffect->saveProperties( doc, rendererElem );
 
+  if ( !mOrderBy.isEmpty() )
+  {
+    QDomElement orderBy = doc.createElement( "orderby" );
+    mOrderBy.save( orderBy );
+    rendererElem.appendChild( orderBy );
+  }
   return rendererElem;
 }
 
@@ -598,6 +616,16 @@ void QgsFeatureRendererV2::setPaintEffect( QgsPaintEffect *effect )
   mPaintEffect = effect;
 }
 
+QgsFeatureRequest::OrderBy QgsFeatureRendererV2::orderBy() const
+{
+  return mOrderBy;
+}
+
+void QgsFeatureRendererV2::setOrderBy( const QgsFeatureRequest::OrderBy& orderBy )
+{
+  mOrderBy = orderBy;
+}
+
 void QgsFeatureRendererV2::convertSymbolSizeScale( QgsSymbolV2 * symbol, QgsSymbolV2::ScaleMethod method, const QString & field )
 {
   if ( symbol->type() == QgsSymbolV2::Marker )

src/core/symbology-ng/qgsrendererv2.h

@@ -21,6 +21,7 @@
 #include "qgsrendercontext.h"
 #include "qgssymbolv2.h"
 #include "qgsfield.h"
+#include "qgsfeaturerequest.h"
 
 #include <QList>
 #include <QString>
@@ -343,6 +344,18 @@ class CORE_EXPORT QgsFeatureRendererV2
      */
     void setForceRasterRender( bool forceRaster ) { mForceRaster = forceRaster; }
 
+    /**
+     * Get the order in which features shall be processed by this renderer.
+     * @note added in QGIS 2.14
+     */
+    QgsFeatureRequest::OrderBy orderBy() const;
+
+    /**
+     * Define the order in which features shall be processed by this renderer.
+     * @note added in QGIS 2.14
+     */
+    void setOrderBy( const QgsFeatureRequest::OrderBy& orderBy );
+
   protected:
     QgsFeatureRendererV2( const QString& type );
 
@@ -366,10 +379,21 @@ class CORE_EXPORT QgsFeatureRendererV2
 
     void setScaleMethodToSymbol( QgsSymbolV2* symbol, int scaleMethod );
 
-    /** Copies paint effect of this renderer to another renderer
+    /**
+     * Clones generic renderer data to another renderer.
+     * Currently clones
+     *  * Order By
+     *  * Paint Effect
+     *
      * @param destRenderer destination renderer for copied effect
      */
-    void copyPaintEffect( QgsFeatureRendererV2 *destRenderer ) const;
+    void copyRendererData( QgsFeatureRendererV2 *destRenderer ) const;
+
+    /** Copies paint effect of this renderer to another renderer
+     * @param destRenderer destination renderer for copied effect
+     * @deprecated use copyRendererData instead
+     */
+    Q_DECL_DEPRECATED void copyPaintEffect( QgsFeatureRendererV2 *destRenderer ) const;
 
     QString mType;
 
@@ -393,6 +417,8 @@ class CORE_EXPORT QgsFeatureRendererV2
      */
     static void convertSymbolRotation( QgsSymbolV2 * symbol, const QString & field );
 
+    QgsFeatureRequest::OrderBy mOrderBy;
+
   private:
     Q_DISABLE_COPY( QgsFeatureRendererV2 )
 };

src/core/symbology-ng/qgsrulebasedrendererv2.cpp

@@ -911,7 +911,7 @@ QgsRuleBasedRendererV2* QgsRuleBasedRendererV2::clone() const
   QgsRuleBasedRendererV2* r = new QgsRuleBasedRendererV2( clonedRoot );
 
   r->setUsingSymbolLevels( usingSymbolLevels() );
-  copyPaintEffect( r );
+  copyRendererData( r );
   return r;
 }
 

src/core/symbology-ng/qgssinglesymbolrendererv2.cpp

@@ -201,7 +201,7 @@ QgsSingleSymbolRendererV2* QgsSingleSymbolRendererV2::clone() const
   QgsSingleSymbolRendererV2* r = new QgsSingleSymbolRendererV2( mSymbol->clone() );
   r->setUsingSymbolLevels( usingSymbolLevels() );
   r->setSizeScaleField( sizeScaleField() );
-  copyPaintEffect( r );
+  copyRendererData( r );
   return r;
 }
 
@@ -381,6 +381,12 @@ QDomElement QgsSingleSymbolRendererV2::save( QDomDocument& doc )
   if ( mPaintEffect && !QgsPaintEffectRegistry::isDefaultStack( mPaintEffect ) )
     mPaintEffect->saveProperties( doc, rendererElem );
 
+  if ( !mOrderBy.isEmpty() )
+  {
+    QDomElement orderBy = doc.createElement( "orderby" );
+    mOrderBy.save( orderBy );
+    rendererElem.appendChild( orderBy );
+  }
   return rendererElem;
 }
 

src/gui/CMakeLists.txt

@@ -238,6 +238,7 @@ SET(QGIS_GUI_SRCS
   qgsnewvectorlayerdialog.cpp
   qgsnumericsortlistviewitem.cpp
   qgsoptionsdialogbase.cpp
+  qgsorderbydialog.cpp
   qgsowssourceselect.cpp
   qgspixmaplabel.cpp
   qgspluginmanagerinterface.cpp
@@ -367,6 +368,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsnewnamedialog.h
   qgsnewvectorlayerdialog.h
   qgsoptionsdialogbase.h
+  qgsorderbydialog.h
   qgsowssourceselect.h
   qgspixmaplabel.h
   qgspluginmanagerinterface.h

src/gui/qgsfieldexpressionwidget.h

@@ -79,7 +79,11 @@ class GUI_EXPORT QgsFieldExpressionWidget : public QWidget
       */
     bool isValidExpression( QString *expressionError = nullptr ) const;
 
+    /**
+     * If the content is not just a simple field this method will return true.
+     */
     bool isExpression() const;
+
     /**
       * Return the current text that is set in the expression area
       */

src/gui/qgsorderbydialog.cpp

@@ -0,0 +1,147 @@
+/***************************************************************************
+ qgosorderbydialog.cpp
+
+ ---------------------
+ begin                : 20.12.2015
+ copyright            : (C) 2015 by Matthias Kuhn
+ email                : matthias@opengis.ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsorderbydialog.h"
+
+#include "qgsexpressionbuilderdialog.h"
+#include "qgsfieldexpressionwidget.h"
+
+#include <QTableWidget>
+#include <QKeyEvent>
+
+QgsOrderByDialog::QgsOrderByDialog( QgsVectorLayer* layer, QWidget* parent )
+    : QDialog( parent )
+    , mLayer( layer )
+{
+  setupUi( this );
+
+  mOrderByTableWidget->horizontalHeader()->setResizeMode( QHeaderView::Stretch );
+  mOrderByTableWidget->horizontalHeader()->setResizeMode( 1, QHeaderView::ResizeToContents );
+  mOrderByTableWidget->horizontalHeader()->setResizeMode( 2, QHeaderView::ResizeToContents );
+
+  mOrderByTableWidget->installEventFilter( this );
+}
+
+void QgsOrderByDialog::setOrderBy( const QgsFeatureRequest::OrderBy& orderBy )
+{
+  mOrderByTableWidget->setRowCount( orderBy.length() + 1 );
+
+  int i = 0;
+  Q_FOREACH ( const QgsFeatureRequest::OrderByClause& orderByClause, orderBy )
+  {
+    setRow( i, orderByClause );
+
+    ++i;
+  }
+
+  // Add an empty widget at the end
+  setRow( i, QgsFeatureRequest::OrderByClause( "" ) );
+}
+
+QgsFeatureRequest::OrderBy QgsOrderByDialog::orderBy()
+{
+  QgsFeatureRequest::OrderBy orderBy;
+
+  for ( int i = 0; i < mOrderByTableWidget->rowCount(); ++i )
+  {
+    QString expressionText = static_cast<QgsFieldExpressionWidget*>( mOrderByTableWidget->cellWidget( i, 0 ) )->currentText();
+
+    if ( ! expressionText.isEmpty() )
+    {
+      bool asc = true;
+      int ascIndex = static_cast<QComboBox*>( mOrderByTableWidget->cellWidget( i, 1 ) )->currentIndex();
+      if ( ascIndex == 1 )
+        asc = false;
+
+      bool nullsFirst = false;
+      int nullsFirstIndex = static_cast<QComboBox*>( mOrderByTableWidget->cellWidget( i, 2 ) )->currentIndex();
+      if ( nullsFirstIndex == 1 )
+        nullsFirst = true;
+
+      QgsFeatureRequest::OrderByClause orderByClause( expressionText, asc, nullsFirst );
+
+      orderBy << orderByClause;
+    }
+  }
+
+  return orderBy;
+}
+
+void QgsOrderByDialog::onExpressionChanged( const QString& expression )
+{
+  // The sender() is the field widget which is the cell widget of the first column
+  int row;
+  for ( row = 0; row < mOrderByTableWidget->rowCount(); ++row )
+  {
+    if ( mOrderByTableWidget->cellWidget( row, 0 ) == sender() )
+    {
+      break;
+    }
+  }
+
+  if ( expression.isEmpty() && row != mOrderByTableWidget->rowCount() - 1 )
+  {
+    mOrderByTableWidget->removeRow( row );
+  }
+  else if ( !expression.isEmpty() && row == mOrderByTableWidget->rowCount() - 1 )
+  {
+    mOrderByTableWidget->insertRow( mOrderByTableWidget->rowCount() );
+    setRow( row + 1, QgsFeatureRequest::OrderByClause( "" ) );
+  }
+}
+
+void QgsOrderByDialog::setRow( int row, const QgsFeatureRequest::OrderByClause& orderByClause )
+{
+  QgsFieldExpressionWidget* fieldExpression = new QgsFieldExpressionWidget();
+  fieldExpression->setLayer( mLayer );
+  fieldExpression->setField( orderByClause.expression().expression() );
+  connect( fieldExpression, SIGNAL( fieldChanged( QString ) ), this, SLOT( onExpressionChanged( QString ) ) );
+
+  QComboBox* ascComboBox = new QComboBox();
+  ascComboBox->addItem( tr( "Ascending" ) );
+  ascComboBox->addItem( tr( "Descencing" ) );
+  ascComboBox->setCurrentIndex( orderByClause.ascending() ? 0 : 1 );
+
+  QComboBox* nullsFirstComboBox = new QComboBox();
+  nullsFirstComboBox->addItem( tr( "NULLs last" ) );
+  nullsFirstComboBox->addItem( tr( "NULLs first" ) );
+  nullsFirstComboBox->setCurrentIndex( orderByClause.nullsFirst() ? 1 : 0 );
+
+  mOrderByTableWidget->setCellWidget( row, 0, fieldExpression );
+  mOrderByTableWidget->setCellWidget( row, 1, ascComboBox );
+  mOrderByTableWidget->setCellWidget( row, 2, nullsFirstComboBox );
+}
+
+bool QgsOrderByDialog::eventFilter( QObject* obj, QEvent* e )
+{
+  Q_UNUSED( obj )
+  Q_ASSERT( obj == mOrderByTableWidget );
+
+  if ( e->type() == QEvent::KeyPress )
+  {
+    QKeyEvent* keyEvent = static_cast<QKeyEvent*>( e );
+
+    if ( keyEvent->key() == Qt::Key_Delete )
+    {
+      if ( mOrderByTableWidget->currentRow() != mOrderByTableWidget->rowCount() - 1 )
+        mOrderByTableWidget->removeRow( mOrderByTableWidget->currentRow() );
+      return true;
+    }
+  }
+
+  return false;
+}
+

src/gui/qgsorderbydialog.h

@@ -0,0 +1,69 @@
+/***************************************************************************
+ qgsorderbydialog.h
+
+ ---------------------
+ begin                : 20.12.2015
+ copyright            : (C) 2015 by Matthias Kuhn
+ email                : matthias@opengis.ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSORDERBYDIALOG_H
+#define QGSORDERBYDIALOG_H
+
+#include <QDialog>
+
+#include "qgsfeaturerequest.h"
+
+#include "ui_qgsorderbydialogbase.h"
+
+/**
+ * This is a dialog to build and manage a list of order by clauses.
+ *
+ * @note added in 2.14
+ */
+
+class GUI_EXPORT QgsOrderByDialog : public QDialog, private Ui::OrderByDialogBase
+{
+    Q_OBJECT
+
+  public:
+    /**
+     * Create a new order by dialog. This helps building order by structures.
+     *
+     * @param layer  The vector layer for which the order by should be produced
+     * @param parent The parent widget, optional
+     */
+    QgsOrderByDialog( QgsVectorLayer* layer, QWidget* parent = nullptr );
+
+    /**
+     * Set the order by to manage
+     */
+    void setOrderBy( const QgsFeatureRequest::OrderBy& orderBy );
+
+    /**
+     * Get the order by defined in the dialog
+     */
+    QgsFeatureRequest::OrderBy orderBy();
+
+  private slots:
+    void onExpressionChanged( const QString& expression );
+
+  private:
+    /**
+     * Initialize a row with the given information
+     */
+    void setRow( int row, const QgsFeatureRequest::OrderByClause& orderByClause );
+
+    QgsVectorLayer* mLayer;
+
+    bool eventFilter( QObject *obj, QEvent *e );
+};
+
+#endif // QGSORDERBYDIALOG_H

src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp

@@ -25,6 +25,7 @@
 #include "qgspointdisplacementrendererwidget.h"
 #include "qgsinvertedpolygonrendererwidget.h"
 #include "qgsheatmaprendererwidget.h"
+#include "qgsorderbydialog.h"
 
 #include "qgsapplication.h"
 #include "qgslogger.h"
@@ -109,13 +110,17 @@ QgsRendererV2PropertiesDialog::QgsRendererV2PropertiesDialog( QgsVectorLayer* la
   connect( mLayerTransparencySpnBx, SIGNAL( valueChanged( int ) ), mLayerTransparencySlider, SLOT( setValue( int ) ) );
 
   //paint effect widget
-  if ( mLayer->rendererV2() && mLayer->rendererV2()->paintEffect() )
+  if ( mLayer->rendererV2() )
   {
-    mPaintEffect = mLayer->rendererV2()->paintEffect()->clone();
-    mEffectWidget->setPaintEffect( mPaintEffect );
+    if ( mLayer->rendererV2()->paintEffect() )
+    {
+      mPaintEffect = mLayer->rendererV2()->paintEffect()->clone();
+      mEffectWidget->setPaintEffect( mPaintEffect );
+    }
+
+    mOrderBy = mLayer->rendererV2()->orderBy();
   }
 
-  QPixmap pix;
   QgsRendererV2Registry* reg = QgsRendererV2Registry::instance();
   QStringList renderers = reg->renderersList();
   Q_FOREACH ( const QString& name, renderers )
@@ -128,21 +133,31 @@ QgsRendererV2PropertiesDialog::QgsRendererV2PropertiesDialog( QgsVectorLayer* la
 
   // setup slot rendererChanged()
   connect( cboRenderers, SIGNAL( currentIndexChanged( int ) ), this, SLOT( rendererChanged() ) );
+  //setup order by
+  if ( mOrderBy.isEmpty() )
+  {
+    btnOrderBy->setEnabled( false );
+    checkboxEnableOrderBy->setChecked( false );
+    lineEditOrderBy->setEnabled( false );
+  }
+  else
+  {
+    checkboxEnableOrderBy->setChecked( true );
+  }
+  lineEditOrderBy->setReadOnly( true );
+  connect( checkboxEnableOrderBy, SIGNAL( toggled( bool ) ), btnOrderBy, SLOT( setEnabled( bool ) ) );
+  connect( checkboxEnableOrderBy, SIGNAL( toggled( bool ) ), lineEditOrderBy, SLOT( setEnabled( bool ) ) );
+  connect( btnOrderBy, SIGNAL( clicked( bool ) ), this, SLOT( showOrderByDialog() ) );
+  lineEditOrderBy->setText( mOrderBy.dump() );
 
   // set current renderer from layer
   QString rendererName = mLayer->rendererV2()->type();
-  for ( int i = 0; i < cboRenderers->count(); i++ )
-  {
-    if ( cboRenderers->itemData( i ).toString() == rendererName )
-    {
-      cboRenderers->setCurrentIndex( i );
-      return;
-    }
-  }
+
+  int rendererIdx = cboRenderers->findData( rendererName );
+  cboRenderers->setCurrentIndex( rendererIdx );
 
   // no renderer found... this mustn't happen
-  Q_ASSERT( false && "there must be a renderer!" );
-
+  Q_ASSERT( rendererIdx != -1 && "there must be a renderer!" );
 }
 
 QgsRendererV2PropertiesDialog::~QgsRendererV2PropertiesDialog()
@@ -223,6 +238,9 @@ void QgsRendererV2PropertiesDialog::apply()
   if ( renderer )
   {
     renderer->setPaintEffect( mPaintEffect->clone() );
+    // set the order by
+    renderer->setOrderBy( mOrderBy );
+
     mLayer->setRendererV2( renderer->clone() );
   }
 
@@ -240,6 +258,18 @@ void QgsRendererV2PropertiesDialog::onOK()
   accept();
 }
 
+void QgsRendererV2PropertiesDialog::showOrderByDialog()
+{
+  QgsOrderByDialog dlg( mLayer );
+
+  dlg.setOrderBy( mOrderBy );
+  if ( dlg.exec() )
+  {
+    mOrderBy = dlg.orderBy();
+    lineEditOrderBy->setText( mOrderBy.dump() );
+  }
+}
+
 
 void QgsRendererV2PropertiesDialog::keyPressEvent( QKeyEvent * e )
 {

src/gui/symbology-ng/qgsrendererv2propertiesdialog.h

@@ -21,6 +21,8 @@
 
 #include "ui_qgsrendererv2propsdialogbase.h"
 
+#include "qgsfeaturerequest.h"
+
 class QKeyEvent;
 
 class QgsVectorLayer;
@@ -52,6 +54,9 @@ class GUI_EXPORT QgsRendererV2PropertiesDialog : public QDialog, private Ui::Qgs
     void apply();
     void onOK();
 
+  private slots:
+    void showOrderByDialog();
+
   protected:
 
     //! Reimplements dialog keyPress event so we can ignore it
@@ -66,6 +71,8 @@ class GUI_EXPORT QgsRendererV2PropertiesDialog : public QDialog, private Ui::Qgs
     QgsPaintEffect* mPaintEffect;
 
     QgsMapCanvas* mMapCanvas;
+
+    QgsFeatureRequest::OrderBy mOrderBy;
 };
 
 

src/providers/mssql/qgsmssqlfeatureiterator.cpp

@@ -197,7 +197,7 @@ void QgsMssqlFeatureIterator::BuildStatement( const QgsFeatureRequest& request )
 
   if ( QSettings().value( "/qgis/compileExpressions", true ).toBool() )
   {
-    Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, request.orderBys() )
+    Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, request.orderBy() )
     {
       if (( clause.ascending() && !clause.nullsFirst() ) || ( !clause.ascending() && clause.nullsFirst() ) )
       {

src/providers/ogr/qgsogrfeatureiterator.cpp

@@ -243,7 +243,7 @@ bool QgsOgrFeatureIterator::rewind()
 
 bool QgsOgrFeatureIterator::close()
 {
-  if ( mClosed )
+  if ( !mConn )
     return false;
 
   iteratorClosed();
@@ -253,7 +253,9 @@ bool QgsOgrFeatureIterator::close()
     OGR_DS_ReleaseResultSet( mConn->ds, ogrLayer );
   }
 
-  QgsOgrConnPool::instance()->releaseConnection( mConn );
+  if ( mConn )
+    QgsOgrConnPool::instance()->releaseConnection( mConn );
+
   mConn = nullptr;
 
   mClosed = true;

src/providers/postgres/qgspostgresfeatureiterator.cpp

@@ -118,7 +118,7 @@ QgsPostgresFeatureIterator::QgsPostgresFeatureIterator( QgsPostgresFeatureSource
 
   if ( QSettings().value( "/qgis/compileExpressions", true ).toBool() )
   {
-    Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, request.orderBys() )
+    Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, request.orderBy() )
     {
       QgsPostgresExpressionCompiler compiler = QgsPostgresExpressionCompiler( source );
       QgsExpression expression = clause.expression();
@@ -313,7 +313,7 @@ bool QgsPostgresFeatureIterator::rewind()
 
 bool QgsPostgresFeatureIterator::close()
 {
-  if ( mClosed )
+  if ( !mConn )
     return false;
 
   mConn->closeCursor( mCursorName );

src/providers/spatialite/qgsspatialitefeatureiterator.cpp

@@ -123,7 +123,7 @@ QgsSpatiaLiteFeatureIterator::QgsSpatiaLiteFeatureIterator( QgsSpatiaLiteFeature
 
   if ( QSettings().value( "/qgis/compileExpressions", true ).toBool() )
   {
-    Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, request.orderBys() )
+    Q_FOREACH ( const QgsFeatureRequest::OrderByClause& clause, request.orderBy() )
     {
       QgsSpatiaLiteExpressionCompiler compiler = QgsSpatiaLiteExpressionCompiler( source );
       QgsExpression expression = clause.expression();
@@ -235,7 +235,7 @@ bool QgsSpatiaLiteFeatureIterator::rewind()
 
 bool QgsSpatiaLiteFeatureIterator::close()
 {
-  if ( mClosed )
+  if ( !mHandle )
     return false;
 
   iteratorClosed();

src/providers/virtual/qgsvirtuallayersqlitemodule.cpp

@@ -188,6 +188,7 @@ private:
         case QVariant::Int:
         case QVariant::UInt:
         case QVariant::Bool:
+        case QVariant::LongLong:
           typeName = "int";
           break;
         case QVariant::Double:
@@ -588,6 +589,9 @@ int vtable_column( sqlite3_vtab_cursor *cursor, sqlite3_context* ctxt, int idx )
       case QVariant::UInt:
         sqlite3_result_int( ctxt, v.toInt() );
         break;
+      case QVariant::LongLong:
+        sqlite3_result_int64( ctxt, v.toLongLong() );
+        break;
       case QVariant::Double:
         sqlite3_result_double( ctxt, v.toDouble() );
         break;

src/ui/qgsorderbydialogbase.ui

@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>OrderByDialogBase</class>
+ <widget class="QDialog" name="OrderByDialogBase">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>747</width>
+    <height>296</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Define order</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="1" column="0">
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="0">
+    <widget class="QTableWidget" name="mOrderByTableWidget">
+     <column>
+      <property name="text">
+       <string>Expression</string>
+      </property>
+     </column>
+     <column>
+      <property name="text">
+       <string>Asc / Desc</string>
+      </property>
+     </column>
+     <column>
+      <property name="text">
+       <string>NULLs handling</string>
+      </property>
+     </column>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>OrderByDialogBase</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>OrderByDialogBase</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>

src/ui/qgsrendererv2propsdialogbase.ui

@@ -85,6 +85,16 @@
       <bool>true</bool>
      </property>
      <layout class="QGridLayout" name="gridLayout">
+      <item row="2" column="0" colspan="4">
+       <widget class="QgsEffectStackCompactWidget" name="mEffectWidget" native="true">
+        <property name="minimumSize">
+         <size>
+          <width>16</width>
+          <height>16</height>
+         </size>
+        </property>
+       </widget>
+      </item>
       <item row="0" column="1" colspan="3">
        <layout class="QHBoxLayout" name="horizontalLayout_2">
         <item>
@@ -133,15 +143,30 @@
       <item row="1" column="1">
        <widget class="QgsBlendModeComboBox" name="mBlendModeComboBox"/>
       </item>
-      <item row="2" column="0" colspan="2">
-       <widget class="QgsEffectStackCompactWidget" name="mEffectWidget" native="true">
-        <property name="minimumSize">
-         <size>
-          <width>16</width>
-          <height>16</height>
-         </size>
-        </property>
-       </widget>
+      <item row="3" column="0" colspan="4">
+       <layout class="QHBoxLayout" name="horizontalLayout_3">
+        <item>
+         <widget class="QCheckBox" name="checkboxEnableOrderBy">
+          <property name="text">
+           <string>Control feature rendering order</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLineEdit" name="lineEditOrderBy">
+          <property name="readOnly">
+           <bool>true</bool>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QToolButton" name="btnOrderBy">
+          <property name="text">
+           <string>...</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
       </item>
      </layout>
     </widget>

tests/src/python/CMakeLists.txt

@@ -54,6 +54,7 @@ ADD_PYTHON_TEST(PyQgsRasterLayer test_qgsrasterlayer.py)
 ADD_PYTHON_TEST(PyQgsRectangle test_qgsrectangle.py)
 ADD_PYTHON_TEST(PyQgsRelation test_qgsrelation.py)
 ADD_PYTHON_TEST(PyQgsRulebasedRenderer test_qgsrulebasedrenderer.py)
+ADD_PYTHON_TEST(PyQgsSingleSymbolRenderer test_qgssinglesymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsShapefileProvider test_provider_shapefile.py)
 ADD_PYTHON_TEST(PyQgsSpatialIndex test_qgsspatialindex.py)
 ADD_PYTHON_TEST(PyQgsSpatialiteProvider test_provider_spatialite.py)

tests/src/python/providertestbase.py

@@ -185,6 +185,11 @@ class ProviderTestCase(object):
         values = [f['pk'] for f in self.provider.getFeatures(request)]
         self.assertEquals(values, [5, 4])
 
+        # Combination with subset of attributes
+        request = QgsFeatureRequest().addOrderBy('num_char', False).setSubsetOfAttributes(['pk'], self.vl.fields())
+        values = [f['pk'] for f in self.vl.getFeatures(request)]
+        self.assertEquals(values, [5, 4, 3, 2, 1])
+
     def testGetFeaturesFidTests(self):
         fids = [f.id() for f in self.provider.getFeatures()]
         assert len(fids) == 5, 'Expected 5 features, got {} instead'.format(len(fids))

tests/src/python/test_qgssinglesymbolrenderer.py

@@ -0,0 +1,90 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    test_qgssinglesymbolrenderer.py
+    ---------------------
+    Date                 : December 2015
+    Copyright            : (C) 2015 by Matthias Kuhn
+    Email                : matthias at opengis dot ch
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+__author__ = 'Matthias Kuhn'
+__date__ = 'December 2015'
+__copyright__ = '(C) 2015, Matthiasd Kuhn'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+import qgis
+import os
+
+from PyQt4.QtCore import QSize
+
+from qgis.core import (QgsVectorLayer,
+                       QgsMapLayerRegistry,
+                       QgsRectangle,
+                       QgsMultiRenderChecker,
+                       QgsSingleSymbolRendererV2,
+                       QgsFillSymbolV2,
+                       QgsMarkerSymbolV2,
+                       QgsRendererCategoryV2,
+                       QgsCategorizedSymbolRendererV2,
+                       QgsGraduatedSymbolRendererV2,
+                       QgsRendererRangeV2,
+                       QgsFeatureRequest
+                       )
+from utilities import (unitTestDataPath,
+                       getQgisTestApp,
+                       TestCase,
+                       unittest
+                       )
+# Convenience instances in case you may need them
+# not used in this test
+QGISAPP, CANVAS, IFACE, PARENT = getQgisTestApp()
+TEST_DATA_DIR = unitTestDataPath()
+
+
+class TestQgsSingleSymbolRenderer(TestCase):
+
+    def setUp(self):
+        myShpFile = os.path.join(TEST_DATA_DIR, 'polys_overlapping.shp')
+        layer = QgsVectorLayer(myShpFile, 'Polys', 'ogr')
+        QgsMapLayerRegistry.instance().addMapLayer(layer)
+
+        # Create rulebased style
+        sym1 = QgsFillSymbolV2.createSimple({'color': '#fdbf6f'})
+
+        self.renderer = QgsSingleSymbolRendererV2(sym1)
+        layer.setRendererV2(self.renderer)
+
+        rendered_layers = [layer.id()]
+        self.mapsettings = CANVAS.mapSettings()
+        self.mapsettings.setOutputSize(QSize(400, 400))
+        self.mapsettings.setOutputDpi(96)
+        self.mapsettings.setExtent(QgsRectangle(-163, 22, -70, 52))
+        self.mapsettings.setLayers(rendered_layers)
+
+    def tearDown(self):
+        QgsMapLayerRegistry.instance().removeAllMapLayers()
+
+    def testOrderBy(self):
+        self.renderer.setOrderBy(QgsFeatureRequest.OrderBy([QgsFeatureRequest.OrderByClause('Value', False)]))
+
+        # Setup rendering check
+        renderchecker = QgsMultiRenderChecker()
+        renderchecker.setMapSettings(self.mapsettings)
+        renderchecker.setControlName('expected_singlesymbol_orderby')
+        result = renderchecker.runTest('singlesymbol_orderby')
+
+        assert result
+
+if __name__ == '__main__':
+    unittest.main()