Fix writing weak relations to XML (#39090)

qgis · Sep 30, 2020 · 612129e · 612129e
1 parent cebc51b
commit 612129e
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Showing 4 changed files with 36 additions and 23 deletions.
diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -2639,17 +2639,17 @@ bool QgsVectorLayer::writeSymbology( QDomNode &node, QDomDocument &doc, QString
     const auto constReferencingRelations { QgsProject::instance()->relationManager()->referencingRelations( this ) };
     for ( const auto &rel : constReferencingRelations )
     {
-      QgsWeakRelation::writeXml( this, rel, referencedLayersElement, doc );
+      QgsWeakRelation::writeXml( this, QgsWeakRelation::Referencing, rel, referencedLayersElement, doc );
     }
 
     // Store referencing layers: relations where "this" is the parent layer (the referenced part, that holds the FK)
     QDomElement referencingLayersElement = doc.createElement( QStringLiteral( "referencingLayers" ) );
     node.appendChild( referencedLayersElement );
 
-    const auto constReferencedRelations { QgsProject::instance()->relationManager()->referencingRelations( this ) };
+    const auto constReferencedRelations { QgsProject::instance()->relationManager()->referencedRelations( this ) };
     for ( const auto &rel : constReferencedRelations )
     {
-      QgsWeakRelation::writeXml( this, rel, referencingLayersElement, doc );
+      QgsWeakRelation::writeXml( this, QgsWeakRelation::Referenced, rel, referencingLayersElement, doc );
     }
 
   }

diff --git a/src/core/qgsweakrelation.cpp b/src/core/qgsweakrelation.cpp
@@ -136,7 +136,7 @@ QgsWeakRelation QgsWeakRelation::readXml( const QgsVectorLayer *layer, WeakRelat
                           QString(), QString(), QString(), QString(), QString(), QList< QgsRelation::FieldPair >() );
 }
 
-void QgsWeakRelation::writeXml( const QgsVectorLayer *layer, const QgsRelation &relation, QDomNode &node, QDomDocument &doc )
+void QgsWeakRelation::writeXml( const QgsVectorLayer *layer, WeakRelationType type, const QgsRelation &relation, QDomNode &node, QDomDocument &doc )
 {
   if ( !layer )
     return;
@@ -147,22 +147,32 @@ void QgsWeakRelation::writeXml( const QgsVectorLayer *layer, const QgsRelation &
   const QgsPathResolver resolver { QgsProject::instance()->pathResolver() };
 
   relation.writeXml( node, doc );
-  QDomElement relationElement = node.firstChildElement( QStringLiteral( "relation" ) );
-  Q_ASSERT( !relationElement.isNull() );
-  if ( layer == relation.referencingLayer() )
-  {
-    // if the layer is the referencing one, we save the referenced layer info
-    relationElement.setAttribute( QStringLiteral( "layerId" ), relation.referencedLayer()->id() );
-    relationElement.setAttribute( QStringLiteral( "layerName" ), relation.referencedLayer()->name() );
-    relationElement.setAttribute( QStringLiteral( "dataSource" ), resolver.writePath( relation.referencedLayer()->publicSource() ) );
-    relationElement.setAttribute( QStringLiteral( "providerKey" ), relation.referencedLayer()->providerType() );
-  }
-  else
+  QDomNodeList relationsNodeList = node.toElement().elementsByTagName( QStringLiteral( "relation" ) );
+  QDomElement relationElement;
+
+  for ( int i = 0; i < relationsNodeList.size(); ++i )
   {
-    // if the layer is the referenced one, we save the referencing layer info
-    relationElement.setAttribute( QStringLiteral( "layerId" ), relation.referencingLayer()->id() );
-    relationElement.setAttribute( QStringLiteral( "layerName" ), relation.referencingLayer()->name() );
-    relationElement.setAttribute( QStringLiteral( "dataSource" ), resolver.writePath( relation.referencingLayer()->publicSource() ) );
-    relationElement.setAttribute( QStringLiteral( "providerKey" ), relation.referencingLayer()->providerType() );
+    relationElement = relationsNodeList.at( i ).toElement();
+    if ( relationElement.hasAttribute( QStringLiteral( "id" ) ) && relationElement.attribute( QStringLiteral( "id" ) ) == relation.id() )
+    {
+      switch ( type )
+      {
+        case Referencing:
+          // if the layer is the referencing one, we save the referenced layer info
+          relationElement.setAttribute( QStringLiteral( "layerId" ), relation.referencedLayer()->id() );
+          relationElement.setAttribute( QStringLiteral( "layerName" ), relation.referencedLayer()->name() );
+          relationElement.setAttribute( QStringLiteral( "dataSource" ), resolver.writePath( relation.referencedLayer()->publicSource() ) );
+          relationElement.setAttribute( QStringLiteral( "providerKey" ), relation.referencedLayer()->providerType() );
+          break;
+
+        case Referenced:
+          // if the layer is the referenced one, we save the referencing layer info
+          relationElement.setAttribute( QStringLiteral( "layerId" ), relation.referencingLayer()->id() );
+          relationElement.setAttribute( QStringLiteral( "layerName" ), relation.referencingLayer()->name() );
+          relationElement.setAttribute( QStringLiteral( "dataSource" ), resolver.writePath( relation.referencingLayer()->publicSource() ) );
+          relationElement.setAttribute( QStringLiteral( "providerKey" ), relation.referencingLayer()->providerType() );
+          break;
+      }
+    }
   }
 }
diff --git a/src/core/qgsweakrelation.h b/src/core/qgsweakrelation.h
@@ -110,12 +110,13 @@ class CORE_EXPORT QgsWeakRelation
      * Writes a weak relation infoto an XML structure. Used for saving .qgs projects
      *
      * \param layer the layer which we save the weak relation for
+     * \param type determines if the layer is referencing or referenced
      * \param relation the relation to save as a weak relation
      * \param node The parent node in which the relation will be created
      * \param doc  The document in which the relation will be saved
      * \since QGIS 3.16
      */
-    static void writeXml( const QgsVectorLayer *layer, const QgsRelation &relation, QDomNode &node, QDomDocument &doc );
+    static void writeXml( const QgsVectorLayer *layer, WeakRelationType type, const QgsRelation &relation, QDomNode &node, QDomDocument &doc );
 
   private:
 

diff --git a/tests/src/core/testqgsweakrelation.cpp b/tests/src/core/testqgsweakrelation.cpp
@@ -136,15 +136,17 @@ void TestQgsWeakRelation::testReadWrite()
       QStringLiteral( "qgis" ), QStringLiteral( "http://mrcc.com/qgis.dtd" ), QStringLiteral( "SYSTEM" ) );
   QDomDocument doc( documentType );
 
+  // Check the XML is written for the referenced layer
   QDomElement node = doc.createElement( QStringLiteral( "relation" ) );
-  QgsWeakRelation::writeXml( &referencedLayer, relation, node, doc );
+  QgsWeakRelation::writeXml( &referencedLayer, QgsWeakRelation::Referenced, relation, node, doc );
   QgsWeakRelation weakRelReferenced( QgsWeakRelation::readXml( &referencedLayer, QgsWeakRelation::Referenced, node,  QgsProject::instance()->pathResolver() ) );
   QCOMPARE( weakRelReferenced.fieldPairs(), fieldPairs );
   QCOMPARE( weakRelReferenced.strength(), QgsRelation::RelationStrength::Association );
   QCOMPARE( weakRelReferenced.referencedLayer().resolve( QgsProject::instance() ), &referencedLayer );
 
+  // Check the XML is written for the referencing layer
   node = doc.createElement( QStringLiteral( "relation" ) );
-  QgsWeakRelation::writeXml( &referencingLayer, relation, node, doc );
+  QgsWeakRelation::writeXml( &referencingLayer, QgsWeakRelation::Referencing, relation, node, doc );
   QgsWeakRelation weakRelReferencing( QgsWeakRelation::readXml( &referencingLayer, QgsWeakRelation::Referencing, node,  QgsProject::instance()->pathResolver() ) );
   QCOMPARE( weakRelReferencing.fieldPairs(), fieldPairs );
   QCOMPARE( weakRelReferencing.strength(), QgsRelation::RelationStrength::Association );