Make constructors for QgsVectorLayer and QgsRasterLayer more flexible

...by moving extra arguments to new LayerOptions structs. This allows us to more easily add new layer constructor options without making the API cumbersome to use.
qgis · Nov 9, 2017 · ba62ffc · ba62ffc
1 parent 61b2f74
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diff --git a/doc/api_break.dox b/doc/api_break.dox
@@ -2080,9 +2080,9 @@ QgsRasterInterface        {#qgis_api_break_3_0_QgsRasterInterface}
 QgsRasterLayer        {#qgis_api_break_3_0_QgsRasterLayer}
 --------------
 
-- The constructor variant with loadDefaultStyleFlag as the 3rd parameter was removed. Use the
-constructor variant which accepts a data provider string and loadDefaultStyleFlag as the
-4th parameter instead.
+- The QgsRasterLayer constructor now takes a QgsRasterLayer.LayerOptions argument instead of the old
+loadDefaultStyle argument.
+- The constructor variant with loadDefaultStyleFlag as the 3rd parameter was removed.
 - setDrawingStyle() was removed. Use setRendererForDrawingStyle() or setRenderer() instead.
 - previewAsPixmap() was removed. Use previewAsImage() instead.
 - updateProgress() had no effect and was removed.
@@ -2551,6 +2551,8 @@ QgsVectorJoinInfo   {#qgis_api_break_3_0_QgsVectorJoinInfo}
 QgsVectorLayer        {#qgis_api_break_3_0_QgsVectorLayer}
 --------------
 
+- The QgsVectorLayer constructor now takes a QgsVectorLayer.LayerOptions argument instead of the old
+loadDefaultStyle argument.
 - excludeAttributesWMS() and setExcludeAttributesWMS() have been renamed to excludeAttributesWms() and
 setExcludeAttributesWms()
 - excludeAttributesWFS() and setExcludeAttributesWFS() have been renamed to excludeAttributesWfs() and

diff --git a/python/core/qgsvectorlayer.sip b/python/core/qgsvectorlayer.sip
@@ -314,22 +314,41 @@ class QgsVectorLayer : QgsMapLayer, QgsExpressionContextGenerator, QgsFeatureSin
       RemoveFromSelection,
     };
 
-    QgsVectorLayer( const QString &path = QString(), const QString &baseName = QString(),
-                    const QString &providerLib = "ogr", bool loadDefaultStyleFlag = true,
-                    bool readExtentFromXml = false );
+    struct LayerOptions
+    {
+
+      explicit LayerOptions( bool loadDefaultStyle = true, bool readExtentFromXml = false );
+%Docstring
+ Constructor for LayerOptions.
+%End
+
+      bool loadDefaultStyle;
+%Docstring
+Set to true if the default layer style should be loaded
+%End
+
+      bool readExtentFromXml;
+%Docstring
+ If true, the layer extent will be read from XML (i.e. stored in the
+ project file). If false, the extent will be determined by the provider on layer load.
+%End
+
+    };
+
+    explicit QgsVectorLayer( const QString &path = QString(), const QString &baseName = QString(),
+                             const QString &providerLib = "ogr", const QgsVectorLayer::LayerOptions &options = QgsVectorLayer::LayerOptions() );
 %Docstring
  Constructor - creates a vector layer
 
  The QgsVectorLayer is constructed by instantiating a data provider.  The provider
  interprets the supplied path (url) of the data source to connect to and access the
  data.
 
- \param  path  The path or url of the parameter.  Typically this encodes
+ \param path  The path or url of the parameter.  Typically this encodes
                parameters used by the data provider as url query items.
- \param  baseName The name used to represent the layer in the legend
- \param  providerLib  The name of the data provider, e.g., "memory", "postgres"
- \param  loadDefaultStyleFlag whether to load the default style
- \param  readExtentFromXml Read extent from XML if true or let provider determine it if false
+ \param baseName The name used to represent the layer in the legend
+ \param providerLib  The name of the data provider, e.g., "memory", "postgres"
+ \param options layer load options
 %End
 
 

diff --git a/python/core/raster/qgsrasterlayer.sip b/python/core/raster/qgsrasterlayer.sip
@@ -146,10 +146,24 @@ class QgsRasterLayer : QgsMapLayer
  Constructor. Provider is not set.
 %End
 
-    QgsRasterLayer( const QString &uri,
-                    const QString &baseName = QString(),
-                    const QString &providerKey = "gdal",
-                    bool loadDefaultStyleFlag = true );
+    struct LayerOptions
+    {
+
+      explicit LayerOptions( bool loadDefaultStyle = true );
+%Docstring
+ Constructor for LayerOptions.
+%End
+
+      bool loadDefaultStyle;
+%Docstring
+Set to true if the default layer style should be loaded
+%End
+    };
+
+    explicit QgsRasterLayer( const QString &uri,
+                             const QString &baseName = QString(),
+                             const QString &providerKey = "gdal",
+                             const QgsRasterLayer::LayerOptions &options = QgsRasterLayer::LayerOptions() );
 %Docstring
  This is the constructor for the RasterLayer class.
 

diff --git a/python/plugins/processing/tests/AlgorithmsTestBase.py b/python/plugins/processing/tests/AlgorithmsTestBase.py
@@ -239,10 +239,14 @@ def load_layer(self, id, param):
             if filepath in self.vector_layer_params:
                 return self.vector_layer_params[filepath]
 
-            lyr = QgsVectorLayer(filepath, param['name'], 'ogr', False)
+            options = QgsVectorLayer.LayerOptions()
+            options.loadDefaultStyle = False
+            lyr = QgsVectorLayer(filepath, param['name'], 'ogr', options)
             self.vector_layer_params[filepath] = lyr
         elif param['type'] == 'raster':
-            lyr = QgsRasterLayer(filepath, param['name'], 'gdal', False)
+            options = QgsRasterLayer.LayerOptions()
+            options.loadDefaultStyle = False
+            lyr = QgsRasterLayer(filepath, param['name'], 'gdal', options)
 
         self.assertTrue(lyr.isValid(), 'Could not load layer "{}" from param {}'.format(filepath, param))
         QgsProject.instance().addMapLayer(lyr)

diff --git a/src/app/dwg/qgsdwgimportdialog.cpp b/src/app/dwg/qgsdwgimportdialog.cpp
@@ -167,7 +167,9 @@ void QgsDwgImportDialog::pbLoadDatabase_clicked()
 
   bool lblVisible = false;
 
-  std::unique_ptr<QgsVectorLayer> d( new QgsVectorLayer( QStringLiteral( "%1|layername=drawing" ).arg( leDatabase->text() ), QStringLiteral( "layers" ), QStringLiteral( "ogr" ), false ) );
+  QgsVectorLayer::LayerOptions options;
+  options.loadDefaultStyle = false;
+  std::unique_ptr<QgsVectorLayer> d( new QgsVectorLayer( QStringLiteral( "%1|layername=drawing" ).arg( leDatabase->text() ), QStringLiteral( "layers" ), QStringLiteral( "ogr" ), options ) );
   if ( d && d->isValid() )
   {
     int idxPath = d->fields().lookupField( QStringLiteral( "path" ) );
@@ -202,7 +204,7 @@ void QgsDwgImportDialog::pbLoadDatabase_clicked()
 
   lblMessage->setVisible( lblVisible );
 
-  std::unique_ptr<QgsVectorLayer> l( new QgsVectorLayer( QStringLiteral( "%1|layername=layers" ).arg( leDatabase->text() ), QStringLiteral( "layers" ), QStringLiteral( "ogr" ), false ) );
+  std::unique_ptr<QgsVectorLayer> l( new QgsVectorLayer( QStringLiteral( "%1|layername=layers" ).arg( leDatabase->text() ), QStringLiteral( "layers" ), QStringLiteral( "ogr" ), options ) );
   if ( l && l->isValid() )
   {
     int idxName = l->fields().lookupField( QStringLiteral( "name" ) );
@@ -278,7 +280,9 @@ void QgsDwgImportDialog::pbImportDrawing_clicked()
 
 QgsVectorLayer *QgsDwgImportDialog::layer( QgsLayerTreeGroup *layerGroup, const QString &layerFilter, const QString &table )
 {
-  QgsVectorLayer *l = new QgsVectorLayer( QStringLiteral( "%1|layername=%2" ).arg( leDatabase->text(), table ), table, QStringLiteral( "ogr" ), false );
+  QgsVectorLayer::LayerOptions options;
+  options.loadDefaultStyle = false;
+  QgsVectorLayer *l = new QgsVectorLayer( QStringLiteral( "%1|layername=%2" ).arg( leDatabase->text(), table ), table, QStringLiteral( "ogr" ), options );
   l->setSubsetString( QStringLiteral( "%1space=0 AND block=-1" ).arg( layerFilter ) );
 
   if ( l->featureCount() == 0 )

diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -4162,7 +4162,9 @@ bool QgisApp::addVectorLayers( const QStringList &layerQStringList, const QStrin
 
     // create the layer
 
-    QgsVectorLayer *layer = new QgsVectorLayer( src, base, QStringLiteral( "ogr" ), false );
+    QgsVectorLayer::LayerOptions options;
+    options.loadDefaultStyle = false;
+    QgsVectorLayer *layer = new QgsVectorLayer( src, base, QStringLiteral( "ogr" ), options );
     Q_CHECK_PTR( layer );
 
     if ( ! layer )
@@ -4636,7 +4638,9 @@ void QgisApp::askUserForOGRSublayers( QgsVectorLayer *layer )
     QString name = fileName + " " + def.layerName;
     if ( !layerGeometryType.isEmpty() )
       name += " " + layerGeometryType;
-    QgsVectorLayer *layer = new QgsVectorLayer( composedURI, name, QStringLiteral( "ogr" ), false );
+    QgsVectorLayer::LayerOptions options;
+    options.loadDefaultStyle = false;
+    QgsVectorLayer *layer = new QgsVectorLayer( composedURI, name, QStringLiteral( "ogr" ), options );
     if ( layer && layer->isValid() )
     {
       myList << layer;
@@ -4714,7 +4718,9 @@ void QgisApp::addDatabaseLayers( QStringList const &layerPathList, QString const
     // create the layer
     QgsDataSourceUri uri( layerPath );
 
-    QgsVectorLayer *layer = new QgsVectorLayer( uri.uri( false ), uri.table(), providerKey, false );
+    QgsVectorLayer::LayerOptions options;
+    options.loadDefaultStyle = false;
+    QgsVectorLayer *layer = new QgsVectorLayer( uri.uri( false ), uri.table(), providerKey, options );
     Q_CHECK_PTR( layer );
 
     if ( ! layer )
@@ -9968,7 +9974,9 @@ QgsVectorLayer *QgisApp::addVectorLayer( const QString &vectorLayerPath, const Q
   }
 
   // create the layer
-  QgsVectorLayer *layer = new QgsVectorLayer( vectorLayerPath, baseName, providerKey, false );
+  QgsVectorLayer::LayerOptions options;
+  options.loadDefaultStyle = false;
+  QgsVectorLayer *layer = new QgsVectorLayer( vectorLayerPath, baseName, providerKey, options );
 
   if ( authok && layer && layer->isValid() )
   {

diff --git a/src/core/processing/qgsprocessingutils.cpp b/src/core/processing/qgsprocessingutils.cpp
@@ -174,12 +174,16 @@ QgsMapLayer *QgsProcessingUtils::loadMapLayerFromString( const QString &string )
   QString name = fi.baseName();
 
   // brute force attempt to load a matching layer
-  std::unique_ptr< QgsVectorLayer > layer( new QgsVectorLayer( string, name, QStringLiteral( "ogr" ), false ) );
+  QgsVectorLayer::LayerOptions options;
+  options.loadDefaultStyle = false;
+  std::unique_ptr< QgsVectorLayer > layer( new QgsVectorLayer( string, name, QStringLiteral( "ogr" ), options ) );
   if ( layer->isValid() )
   {
     return layer.release();
   }
-  std::unique_ptr< QgsRasterLayer > rasterLayer( new QgsRasterLayer( string, name, QStringLiteral( "gdal" ), false ) );
+  QgsRasterLayer::LayerOptions rasterOptions;
+  rasterOptions.loadDefaultStyle = false;
+  std::unique_ptr< QgsRasterLayer > rasterLayer( new QgsRasterLayer( string, name, QStringLiteral( "gdal" ), rasterOptions ) );
   if ( rasterLayer->isValid() )
   {
     return rasterLayer.release();

diff --git a/src/core/qgsprojectfiletransform.cpp b/src/core/qgsprojectfiletransform.cpp
@@ -340,7 +340,9 @@ void QgsProjectFileTransform::transform0110to1000()
       QString providerKey = providerNode.toElement().text();
 
       //create the layer to get the provider for int->fieldName conversion
-      QgsVectorLayer *layer = new QgsVectorLayer( dataSource, QLatin1String( "" ), providerKey, false );
+      QgsVectorLayer::LayerOptions options;
+      options.loadDefaultStyle = false;
+      QgsVectorLayer *layer = new QgsVectorLayer( dataSource, QLatin1String( "" ), providerKey, options );
       if ( !layer->isValid() )
       {
         delete layer;

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -136,13 +136,12 @@ typedef bool deleteStyleById_t(
 QgsVectorLayer::QgsVectorLayer( const QString &vectorLayerPath,
                                 const QString &baseName,
                                 const QString &providerKey,
-                                bool loadDefaultStyleFlag,
-                                bool readExtentFromXml )
+                                const LayerOptions &options )
   : QgsMapLayer( VectorLayer, baseName, vectorLayerPath )
   , mProviderKey( providerKey )
   , mAuxiliaryLayer( nullptr )
   , mAuxiliaryLayerKey( QString() )
-  , mReadExtentFromXml( readExtentFromXml )
+  , mReadExtentFromXml( options.readExtentFromXml )
 {
   mActions = new QgsActionManager( this );
   mConditionalStyles = new QgsConditionalLayerStyles();
@@ -153,7 +152,7 @@ QgsVectorLayer::QgsVectorLayer( const QString &vectorLayerPath,
   // if we're given a provider type, try to create and bind one to this layer
   if ( !vectorLayerPath.isEmpty() && !mProviderKey.isEmpty() )
   {
-    setDataSource( vectorLayerPath, baseName, providerKey, loadDefaultStyleFlag );
+    setDataSource( vectorLayerPath, baseName, providerKey, options.loadDefaultStyle );
   }
 
   connect( this, &QgsVectorLayer::selectionChanged, this, [ = ] { emit repaintRequested(); } );

diff --git a/src/core/qgsvectorlayer.h b/src/core/qgsvectorlayer.h
@@ -381,24 +381,47 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
       RemoveFromSelection, //!< Remove from current selection
     };
 
+    /**
+     * Setting options for loading vector layers.
+     * \since QGIS 3.0
+     */
+    struct LayerOptions
+    {
+
+      /**
+       * Constructor for LayerOptions.
+       */
+      explicit LayerOptions( bool loadDefaultStyle = true, bool readExtentFromXml = false )
+        : loadDefaultStyle( loadDefaultStyle )
+        , readExtentFromXml( readExtentFromXml )
+      {}
+
+      //! Set to true if the default layer style should be loaded
+      bool loadDefaultStyle = true;
+
+      /**
+       * If true, the layer extent will be read from XML (i.e. stored in the
+       * project file). If false, the extent will be determined by the provider on layer load.
+       */
+      bool readExtentFromXml = false;
+
+    };
+
     /**
      * Constructor - creates a vector layer
      *
      * The QgsVectorLayer is constructed by instantiating a data provider.  The provider
      * interprets the supplied path (url) of the data source to connect to and access the
      * data.
      *
-     * \param  path  The path or url of the parameter.  Typically this encodes
+     * \param path  The path or url of the parameter.  Typically this encodes
      *               parameters used by the data provider as url query items.
-     * \param  baseName The name used to represent the layer in the legend
-     * \param  providerLib  The name of the data provider, e.g., "memory", "postgres"
-     * \param  loadDefaultStyleFlag whether to load the default style
-     * \param  readExtentFromXml Read extent from XML if true or let provider determine it if false
-     *
+     * \param baseName The name used to represent the layer in the legend
+     * \param providerLib  The name of the data provider, e.g., "memory", "postgres"
+     * \param options layer load options
      */
-    QgsVectorLayer( const QString &path = QString(), const QString &baseName = QString(),
-                    const QString &providerLib = "ogr", bool loadDefaultStyleFlag = true,
-                    bool readExtentFromXml = false );
+    explicit QgsVectorLayer( const QString &path = QString(), const QString &baseName = QString(),
+                             const QString &providerLib = "ogr", const QgsVectorLayer::LayerOptions &options = QgsVectorLayer::LayerOptions() );
 
 
     virtual ~QgsVectorLayer();

diff --git a/src/core/raster/qgsrasterlayer.cpp b/src/core/raster/qgsrasterlayer.cpp
@@ -108,7 +108,7 @@ QgsRasterLayer::QgsRasterLayer()
 QgsRasterLayer::QgsRasterLayer( const QString &uri,
                                 const QString &baseName,
                                 const QString &providerKey,
-                                bool loadDefaultStyleFlag )
+                                const LayerOptions &options )
   : QgsMapLayer( RasterLayer, baseName, uri )
     // Constant that signals property not used.
   , QSTRING_NOT_SET( QStringLiteral( "Not Set" ) )
@@ -122,7 +122,7 @@ QgsRasterLayer::QgsRasterLayer( const QString &uri,
 
   // load default style
   bool defaultLoadedFlag = false;
-  if ( mValid && loadDefaultStyleFlag )
+  if ( mValid && options.loadDefaultStyle )
   {
     loadDefaultStyle( defaultLoadedFlag );
   }

diff --git a/src/core/raster/qgsrasterlayer.h b/src/core/raster/qgsrasterlayer.h
@@ -166,6 +166,24 @@ class CORE_EXPORT QgsRasterLayer : public QgsMapLayer
     //! \brief Constructor. Provider is not set.
     QgsRasterLayer();
 
+    /**
+     * Setting options for loading raster layers.
+     * \since QGIS 3.0
+     */
+    struct LayerOptions
+    {
+
+      /**
+       * Constructor for LayerOptions.
+       */
+      explicit LayerOptions( bool loadDefaultStyle = true )
+        : loadDefaultStyle( loadDefaultStyle )
+      {}
+
+      //! Set to true if the default layer style should be loaded
+      bool loadDefaultStyle = true;
+    };
+
     /**
      * \brief This is the constructor for the RasterLayer class.
      *
@@ -183,10 +201,10 @@ class CORE_EXPORT QgsRasterLayer : public QgsMapLayer
      *
      * -
      * */
-    QgsRasterLayer( const QString &uri,
-                    const QString &baseName = QString(),
-                    const QString &providerKey = "gdal",
-                    bool loadDefaultStyleFlag = true );
+    explicit QgsRasterLayer( const QString &uri,
+                             const QString &baseName = QString(),
+                             const QString &providerKey = "gdal",
+                             const QgsRasterLayer::LayerOptions &options = QgsRasterLayer::LayerOptions() );
 
     ~QgsRasterLayer();
 

diff --git a/src/providers/ogr/qgsogrdataitems.cpp b/src/providers/ogr/qgsogrdataitems.cpp
@@ -229,7 +229,9 @@ QList<QgsOgrDbLayerInfo *> QgsOgrLayerItem::subLayers( const QString &path, cons
     }
   }
   // Raster layers
-  QgsRasterLayer rlayer( path, QStringLiteral( "gdal_tmp" ), QStringLiteral( "gdal" ), false );
+  QgsRasterLayer::LayerOptions options;
+  options.loadDefaultStyle = false;
+  QgsRasterLayer rlayer( path, QStringLiteral( "gdal_tmp" ), QStringLiteral( "gdal" ), options );
   if ( !rlayer.dataProvider()->subLayers( ).empty() )
   {
     const QStringList layers( rlayer.dataProvider()->subLayers( ) );