Implementation of QgsMeshLayer::reload() and QgsMdalProvider::reloadD…

…ata()

Implementation of this override method permit to reload mesh end dataset groups when the data changed outside of the QGIS application.

python/core/auto_generated/mesh/qgsmeshlayer.sip.in

@@ -133,6 +133,9 @@ QgsMeshLayer cannot be copied.
     virtual bool writeXml( QDomNode &layer_node, QDomDocument &doc, const QgsReadWriteContext &context ) const;
 
 
+    virtual void reload();
+
+
     QString providerType() const;
 %Docstring
 Returns the provider type for this layer

src/core/mesh/qgsmeshlayer.cpp

@@ -457,6 +457,27 @@ bool QgsMeshLayer::writeXml( QDomNode &layer_node, QDomDocument &document, const
   return writeSymbology( layer_node, document, errorMsg, context );
 }
 
+void QgsMeshLayer::reload()
+{
+  if ( mDataProvider && mDataProvider->isValid() )
+  {
+
+    mDataProvider->reloadData();
+
+    //reload the mesh structure
+    if ( !mNativeMesh )
+      mNativeMesh.reset( new QgsMesh );
+
+    dataProvider()->populateMesh( mNativeMesh.get() );
+
+    //clear the TriangularMesh
+    mTriangularMesh.reset( new QgsTriangularMesh() );
+
+    //clear the rendererCache
+    mRendererCache.reset( new QgsMeshLayerRendererCache() );
+  }
+}
+
 bool QgsMeshLayer::setDataProvider( QString const &provider, const QgsDataProvider::ProviderOptions &options )
 {
   delete mDataProvider;

src/core/mesh/qgsmeshlayer.h

@@ -146,6 +146,8 @@ class CORE_EXPORT QgsMeshLayer : public QgsMapLayer
     bool readXml( const QDomNode &layer_node, QgsReadWriteContext &context ) override;
     bool writeXml( QDomNode &layer_node, QDomDocument &doc, const QgsReadWriteContext &context ) const override;
 
+    void reload() override;
+
     //! Returns the provider type for this layer
     QString providerType() const;
 

src/providers/mdal/qgsmdalprovider.cpp

@@ -54,14 +54,7 @@ QgsCoordinateReferenceSystem QgsMdalProvider::crs() const
 QgsMdalProvider::QgsMdalProvider( const QString &uri, const ProviderOptions &options )
   : QgsMeshDataProvider( uri, options )
 {
-  QByteArray curi = uri.toUtf8();
-  mMeshH = MDAL_LoadMesh( curi.constData() );
-  if ( mMeshH )
-  {
-    const QString proj = MDAL_M_projection( mMeshH );
-    if ( !proj.isEmpty() )
-      mCrs.createFromString( proj );
-  }
+  loadData();
 }
 
 QgsMdalProvider::~QgsMdalProvider()
@@ -241,6 +234,32 @@ bool QgsMdalProvider::persistDatasetGroup( const QString &path,
   return false;
 }
 
+void QgsMdalProvider::loadData()
+{
+  QByteArray curi = dataSourceUri().toUtf8();
+  mMeshH = MDAL_LoadMesh( curi.constData() );
+  if ( mMeshH )
+  {
+    const QString proj = MDAL_M_projection( mMeshH );
+    if ( !proj.isEmpty() )
+      mCrs.createFromString( proj );
+  }
+}
+
+void QgsMdalProvider::reloadData()
+{
+  if ( mMeshH )
+    MDAL_CloseMesh( mMeshH );
+
+  loadData();
+
+  if ( mMeshH )
+    for ( auto uri : mExtraDatasetUris )
+    {
+      std::string str = uri.toStdString();
+      MDAL_M_LoadDatasets( mMeshH, str.c_str() );
+    }
+}
 
 void QgsMdalProvider::fileMeshFilters( QString &fileMeshFiltersString, QString &fileMeshDatasetFiltersString )
 {

src/providers/mdal/qgsmdalprovider.h

@@ -77,6 +77,8 @@ class QgsMdalProvider : public QgsMeshDataProvider
                               const QVector<double> &times
                             ) override;
 
+    void reloadData() override;
+
     /**
      * Returns file filters for meshes and datasets to be used in Open File Dialogs
      * \param fileMeshFiltersString file mesh filters
@@ -102,6 +104,7 @@ class QgsMdalProvider : public QgsMeshDataProvider
   private:
     QVector<QgsMeshVertex> vertices( ) const;
     QVector<QgsMeshFace> faces( ) const;
+    void loadData();
     MeshH mMeshH;
     QStringList mExtraDatasetUris;
     QgsCoordinateReferenceSystem mCrs;