Add expression constructor to QgsFeatureRequest

Author: m-kuhn

python/core/qgsfeaturerequest.sip

@@ -30,6 +30,8 @@ class QgsFeatureRequest
     explicit QgsFeatureRequest( QgsFeatureId fid );
     //! construct a request with rectangle filter
     explicit QgsFeatureRequest( const QgsRectangle& rect );
+    //! construct a request with a filter expression
+    explicit QgsFeatureRequest( const QgsExpression& expression );
 
     FilterType filterType() const;
 

src/core/qgsfeaturerequest.cpp

@@ -42,6 +42,13 @@ QgsFeatureRequest::QgsFeatureRequest( const QgsRectangle& rect )
 {
 }
 
+QgsFeatureRequest::QgsFeatureRequest( const QgsExpression& expr )
+    : mFilter( FilterExpression )
+    , mFilterExpression( new QgsExpression( expr.dump() ) )
+    , mFlags( 0 )
+{
+}
+
 QgsFeatureRequest::QgsFeatureRequest( const QgsFeatureRequest &rh )
 {
   operator=( rh );

src/core/qgsfeaturerequest.h

@@ -80,6 +80,8 @@ class CORE_EXPORT QgsFeatureRequest
     explicit QgsFeatureRequest( QgsFeatureId fid );
     //! construct a request with rectangle filter
     explicit QgsFeatureRequest( const QgsRectangle& rect );
+    //! construct a request with a filter expression
+    explicit QgsFeatureRequest( const QgsExpression& expr );
     //! copy constructor
     QgsFeatureRequest( const QgsFeatureRequest& rh );