Set filter on iterator:

Author: NathanW2

src/providers/ogr/qgsogrfeatureiterator.cpp

@@ -32,8 +32,9 @@
 
 
 QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrProvider* p, const QgsFeatureRequest& request )
-  : QgsAbstractFeatureIterator( request ), P( p ), ogrDataSource(0), ogrLayer(0), ogrDriver(0)
+  : QgsAbstractFeatureIterator( request ), P( p ), ogrDataSource(0), ogrLayer(0), mSubsetStringSet(false)
 {
+  mFeatureFetched = false;
 
   ogrDataSource = OGROpen( TO8F( P->filePath() ), false, NULL );
 
@@ -46,7 +47,15 @@ QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrProvider* p, const QgsFeatur
     ogrLayer = OGR_DS_GetLayerByName( ogrDataSource, TO8( p->layerName() ) );
   }
 
-  mFeatureFetched = false;
+  if ( !P->subsetString().isEmpty() )
+  {
+      QString sql = QString( "SELECT * FROM %1 WHERE %2" )
+                    .arg( P->quotedIdentifier( FROM8( OGR_FD_GetName( OGR_L_GetLayerDefn( ogrLayer ) ) ) ) )
+                    .arg( P->subsetString() );
+      QgsDebugMsg( QString( "SQL: %1" ).arg( sql ) );
+      ogrLayer = OGR_DS_ExecuteSQL( ogrDataSource, P->textEncoding()->fromUnicode( sql ).constData(), NULL, NULL );
+      mSubsetStringSet = true;
+  }
 
   ensureRelevantFields();
 
@@ -150,6 +159,11 @@ bool QgsOgrFeatureIterator::close()
   if ( mClosed )
     return false;
 
+  if (mSubsetStringSet)
+  {
+    OGR_DS_ReleaseResultSet(ogrDataSource, ogrLayer );
+  }
+
   OGR_DS_Destroy( ogrDataSource );
 
   mClosed = true;

src/providers/ogr/qgsogrfeatureiterator.h

@@ -51,6 +51,8 @@ class QgsOgrFeatureIterator : public QgsAbstractFeatureIterator
 
     OGRDataSourceH ogrDataSource;
     OGRLayerH ogrLayer;
+
+    bool mSubsetStringSet;
 };
 
 

src/providers/ogr/qgsogrprovider.h

@@ -15,6 +15,8 @@ email                : sherman at mrcc.com
  *                                                                         *
  ***************************************************************************/
 
+#include "QTextCodec"
+
 #include "qgsrectangle.h"
 #include "qgsvectordataprovider.h"
 #include "qgsvectorfilewriter.h"
@@ -256,6 +258,10 @@ class QgsOgrProvider : public QgsVectorDataProvider
 
     int layerIndex() { return mLayerIndex; }
 
+    QTextCodec* textEncoding() { return mEncoding; }
+
+    QString quotedIdentifier( QString field );
+
   protected:
     /** loads fields from input file to member attributeFields */
     void loadFields();
@@ -329,8 +335,6 @@ class QgsOgrProvider : public QgsVectorDataProvider
     /**Deletes one feature*/
     bool deleteFeature( QgsFeatureId id );
 
-    QString quotedIdentifier( QString field );
-
     /**Calls OGR_L_SyncToDisk and recreates the spatial index if present*/
     bool syncToDisc();