Add QgsMapLayer::isSpatial() method

The current approach of testing !vl || vl->geometryType() != NoGeometry
is not intuitive and has been the source of 2 recent bugs.

Replacing these tests with the new isSpatial() function makes it
immediately obvious what is being tested. It also allows for
non-spatial plugin layers to be correctly handled by overriding
this method.

python/core/qgsmaplayer.sip

@@ -273,6 +273,11 @@ class QgsMapLayer : QObject
     /** True if the layer can be edited */
     virtual bool isEditable() const;
 
+    /** Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it.
+     * @note added in QGIS 2.16
+     */
+    virtual bool isSpatial() const;
+
     /** Sets state from Dom document
        @param layerElement The Dom element corresponding to ``maplayer'' tag
        @note

python/core/qgsvectorlayer.sip

@@ -975,6 +975,8 @@ class QgsVectorLayer : QgsMapLayer
     /** Returns true if the provider is in editing mode */
     virtual bool isEditable() const;
 
+    virtual bool isSpatial() const;
+
     /** Returns true if the provider is in read-only mode */
     virtual bool isReadOnly() const;
 

python/core/raster/qgsrasterlayer.sip

@@ -144,6 +144,8 @@ class QgsRasterLayer : QgsMapLayer
     /** Returns a list with classification items (Text and color) */
     QList< QPair< QString, QColor > > legendSymbologyItems() const;
 
+    virtual bool isSpatial() const;
+
     /** \brief Obtain GDAL Metadata for this layer */
     QString metadata();
 

src/app/qgsapplayertreeviewmenuprovider.cpp

@@ -101,7 +101,7 @@ QMenu* QgsAppLayerTreeViewMenuProvider::createContextMenu()
       // duplicate layer
       QAction* duplicateLayersAction = menu->addAction( QgsApplication::getThemeIcon( "/mActionDuplicateLayer.svg" ), tr( "&Duplicate" ), QgisApp::instance(), SLOT( duplicateLayers() ) );
 
-      if ( !vlayer || vlayer->geometryType() != QGis::NoGeometry )
+      if ( layer->isSpatial() )
       {
         // set layer scale visibility
         menu->addAction( tr( "&Set Layer Scale Visibility" ), QgisApp::instance(), SLOT( setLayerScaleVisibility() ) );

src/core/qgsmaplayer.h

@@ -289,6 +289,11 @@ class CORE_EXPORT QgsMapLayer : public QObject
     /** True if the layer can be edited */
     virtual bool isEditable() const;
 
+    /** Returns true if the layer is considered a spatial layer, ie it has some form of geometry associated with it.
+     * @note added in QGIS 2.16
+     */
+    virtual bool isSpatial() const { return true; }
+
     /** Sets state from Dom document
        @param layerElement The Dom element corresponding to ``maplayer'' tag
        @note

src/core/qgsvectorlayer.cpp

@@ -2618,6 +2618,11 @@ bool QgsVectorLayer::isEditable() const
   return ( mEditBuffer && mDataProvider );
 }
 
+bool QgsVectorLayer::isSpatial() const
+{
+  return geometryType() != QGis::NoGeometry;
+}
+
 bool QgsVectorLayer::isReadOnly() const
 {
   return mReadOnly;

src/core/qgsvectorlayer.h

@@ -1088,6 +1088,8 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
     /** Returns true if the provider is in editing mode */
     virtual bool isEditable() const override;
 
+    virtual bool isSpatial() const override;
+
     /** Returns true if the provider is in read-only mode */
     virtual bool isReadOnly() const;
 

src/core/raster/qgsrasterlayer.h

@@ -280,6 +280,8 @@ class CORE_EXPORT QgsRasterLayer : public QgsMapLayer
     /** Returns a list with classification items (Text and color) */
     QgsLegendColorList legendSymbologyItems() const;
 
+    virtual bool isSpatial() const override { return true; }
+
     /** \brief Obtain GDAL Metadata for this layer */
     QString metadata() override;
 

src/gui/layertree/qgslayertreemapcanvasbridge.cpp

@@ -143,8 +143,7 @@ void QgsLayerTreeMapCanvasBridge::setCanvasLayers()
         if ( !layerNode->layer() )
           continue;
 
-        QgsVectorLayer *vl = qobject_cast<QgsVectorLayer *>( layerNode->layer() );
-        if ( !vl || vl->geometryType() != QGis::NoGeometry )
+        if ( layerNode->layer()->isSpatial() )
         {
           mCanvas->setDestinationCrs( layerNode->layer()->crs() );
           mCanvas->setMapUnits( layerNode->layer()->crs().mapUnits() );

tests/src/core/testqgsrasterlayer.cpp

@@ -69,6 +69,7 @@ class TestQgsRasterLayer : public QObject
     void cleanup() {} // will be called after every testfunction.
 
     void isValid();
+    void isSpatial();
     void pseudoColor();
     void colorRamp1();
     void colorRamp2();
@@ -205,6 +206,11 @@ void TestQgsRasterLayer::isValid()
   QVERIFY( render( "raster" ) );
 }
 
+void TestQgsRasterLayer::isSpatial()
+{
+  QVERIFY( mpRasterLayer->isSpatial() );
+}
+
 void TestQgsRasterLayer::pseudoColor()
 {
   QgsRasterShader* rasterShader = new QgsRasterShader();

tests/src/core/testqgsvectorlayer.cpp

@@ -104,6 +104,7 @@ class TestQgsVectorLayer : public QObject
     void uniqueValues();
     void minimumValue();
     void maximumValue();
+    void isSpatial();
 };
 
 void TestQgsVectorLayer::initTestCase()
@@ -341,5 +342,13 @@ void TestQgsVectorLayer::maximumValue()
   QCOMPARE( vLayer->maximumValue( 1000 ), QVariant() );
 }
 
+void TestQgsVectorLayer::isSpatial()
+{
+  QVERIFY( mpPointsLayer->isSpatial() );
+  QVERIFY( mpPolysLayer->isSpatial() );
+  QVERIFY( mpLinesLayer->isSpatial() );
+  QVERIFY( !mpNonSpatialLayer->isSpatial() );
+}
+
 QTEST_MAIN( TestQgsVectorLayer )
 #include "testqgsvectorlayer.moc"