[FEATURE] add row cache for attribute table

Author: jef-n

images/images.qrc

@@ -203,6 +203,7 @@
         <file>themes/default/propertyicons/rendering.png</file>
         <file>themes/default/propertyicons/symbology.png</file>
         <file>themes/default/propertyicons/transparency.png</file>
+        <file>themes/default/propertyicons/gdal.png</file>
         <file>themes/default/qgis.xpm</file>
         <file>themes/default/rendererCategorizedSymbol.png</file>
         <file>themes/default/rendererGraduatedSymbol.png</file>

src/app/qgsoptions.cpp

@@ -67,7 +67,7 @@ QgsOptions::QgsOptions( QWidget *parent, Qt::WFlags fl ) :
   cmbSize->addItem( "32" );
 
   QStringList styles = QStyleFactory::keys();
-  foreach(QString style, styles )
+  foreach( QString style, styles )
   {
     cmbStyle->addItem( style );
   }
@@ -182,6 +182,8 @@ QgsOptions::QgsOptions( QWidget *parent, Qt::WFlags fl ) :
   cmbAttrTableBehaviour->addItem( tr( "Show features in current canvas" ) );
   cmbAttrTableBehaviour->setCurrentIndex( settings.value( "/qgis/attributeTableBehaviour", 0 ).toInt() );
 
+  spinBoxAttrTableRowCache->setValue( settings.value( "/qgis/attributeTableRowCache", 10000 ).toInt() );
+
   // set the display update threshold
   spinBoxUpdateThreshold->setValue( settings.value( "/Map/updateThreshold" ).toInt() );
   //set the default projection behaviour radio buttongs
@@ -584,6 +586,7 @@ void QgsOptions::saveOptions()
   settings.setValue( "/qgis/showTips", cbxShowTips->isChecked() );
   settings.setValue( "/qgis/dockAttributeTable", cbxAttributeTableDocked->isChecked() );
   settings.setValue( "/qgis/attributeTableBehaviour", cmbAttrTableBehaviour->currentIndex() );
+  settings.setValue( "/qgis/attributeTableRowCache", spinBoxAttrTableRowCache->value() );
   settings.setValue( "/qgis/dockIdentifyResults", cbxIdentifyResultsDocked->isChecked() );
   settings.setValue( "/qgis/dockSnapping", cbxSnappingOptionsDocked->isChecked() );
   settings.setValue( "/qgis/addPostgisDC", cbxAddPostgisDC->isChecked() );

src/gui/attributetable/qgsattributetablememorymodel.h

@@ -81,8 +81,6 @@ class QgsAttributeTableMemoryModel : public QgsAttributeTableModel
      * Loads the layer into the model
      */
     virtual void loadLayer();
-
-    QHash<QgsFeatureId, QgsFeature> mFeatureMap;
 };
 
 #endif //QGSATTRIBUTETABLEMEMORYMODEL_H

src/gui/attributetable/qgsattributetablemodel.cpp

@@ -33,6 +33,9 @@ QgsAttributeTableModel::QgsAttributeTableModel( QgsVectorLayer *theLayer, QObjec
     : QAbstractTableModel( parent )
 {
   mFeat.setFeatureId( std::numeric_limits<int>::min() );
+  mFeatureMap.clear();
+  mFeatureQueue.clear();
+
   mLayer = theLayer;
   loadAttributes();
 
@@ -50,9 +53,33 @@ bool QgsAttributeTableModel::featureAtId( QgsFeatureId fid ) const
   QgsDebugMsgLevel( QString( "loading feature %1" ).arg( fid ), 3 );
 
   if ( fid == std::numeric_limits<int>::min() )
+  {
     return false;
+  }
+  else if ( mFeatureMap.contains( fid ) )
+  {
+    mFeat = mFeatureMap[ fid ];
+    return true;
+  }
+  else if ( mLayer->featureAtId( fid, mFeat, false, true ) )
+  {
+    QSettings settings;
+    int cacheSize = settings.value( "/qgis/attributeTableRowCache", "10000" ).toInt();
+
+    if ( mFeatureQueue.size() == cacheSize )
+    {
+      mFeatureMap.remove( mFeatureQueue.dequeue() );
+    }
+
+    mFeatureQueue.enqueue( fid );
+    mFeatureMap.insert( fid, mFeat );
+
+    return true;
+  }
   else
-    return mLayer->featureAtId( fid, mFeat, false, true );
+  {
+    return false;
+  }
 }
 
 void QgsAttributeTableModel::featureDeleted( QgsFeatureId fid )
@@ -152,6 +179,10 @@ void QgsAttributeTableModel::layerDeleted()
 
 void QgsAttributeTableModel::attributeValueChanged( QgsFeatureId fid, int idx, const QVariant &value )
 {
+  if ( mFeatureMap.contains( fid ) )
+  {
+    mFeatureMap[ fid ].changeAttribute( fieldCol( idx ), value );
+  }
   setData( index( idToRow( fid ), fieldCol( idx ) ), value, Qt::EditRole );
 }
 

src/gui/attributetable/qgsattributetablemodel.h

@@ -21,6 +21,7 @@
 #include <QModelIndex>
 #include <QObject>
 #include <QHash>
+#include <QQueue>
 
 #include "qgsfeature.h" // QgsAttributeMap
 #include "qgsvectorlayer.h" // QgsAttributeList
@@ -196,6 +197,7 @@ class GUI_EXPORT QgsAttributeTableModel: public QAbstractTableModel
     int mFieldCount;
 
     mutable QgsFeature mFeat;
+    mutable QHash<QgsFeatureId, QgsFeature> mFeatureMap;
 
     QgsAttributeList mAttributes;
     QMap< int, const QMap<QString, QVariant> * > mValueMaps;
@@ -228,6 +230,10 @@ class GUI_EXPORT QgsAttributeTableModel: public QAbstractTableModel
      * @return feature exists
      */
     virtual bool featureAtId( QgsFeatureId fid ) const;
+
+  private:
+    mutable QQueue<QgsFeatureId> mFeatureQueue;
+
 };