Add storeInvalidLayersProperties to store invalid layers

This can be used to restore initial layer status or to apply styles and other layer properties if the data source is changed. The idea is that the user can fix bad layers at any time, and by setting a new datasource she probably wants to keep the original layer properties.
qgis · Nov 5, 2018 · 1b041f4 · 1b041f4
1 parent bcd8581
commit 1b041f4
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Showing 3 changed files with 50 additions and 2 deletions.
diff --git a/python/core/auto_generated/layertree/qgslayertreeutils.sip.in b/python/core/auto_generated/layertree/qgslayertreeutils.sip.in
@@ -56,7 +56,14 @@ Returns true if any of the layers is modified
 
     static void removeInvalidLayers( QgsLayerTreeGroup *group );
 %Docstring
-Remove layer nodes that refer to invalid layers
+Removes layer nodes that refer to invalid layers
+%End
+
+    static void storeInvalidLayersProperties( QgsLayerTreeGroup *group, const QDomDocument *doc );
+%Docstring
+Stores in a custom layer node property the layer properties XML information for an invalid layer
+
+.. versionadded:: 3.6
 %End
 
     static void replaceChildrenOfEmbeddedGroups( QgsLayerTreeGroup *group );

diff --git a/src/core/layertree/qgslayertreeutils.cpp b/src/core/layertree/qgslayertreeutils.cpp
@@ -306,6 +306,40 @@ void QgsLayerTreeUtils::removeInvalidLayers( QgsLayerTreeGroup *group )
     group->removeChildNode( node );
 }
 
+void QgsLayerTreeUtils::storeInvalidLayersProperties( QgsLayerTreeGroup *group,  const QDomDocument *doc )
+{
+  const QDomNodeList mlNodeList( doc->documentElement()
+                                 .firstChildElement( QStringLiteral( "projectlayers" ) )
+                                 .elementsByTagName( QStringLiteral( "maplayer" ) ) );
+  for ( QgsLayerTreeNode *node : group->children() )
+  {
+    if ( QgsLayerTree::isLayer( node ) )
+    {
+      QgsMapLayer *l( QgsLayerTree::toLayer( node )->layer() );
+      if ( l && ! l->isValid( ) )
+      {
+        for ( int i = 0; i < mlNodeList.count(); i++ )
+        {
+          QDomNode mlNode( mlNodeList.at( i ) );
+          QString id( mlNode.firstChildElement( QStringLiteral( "id" ) ).firstChild().nodeValue() );
+          if ( id == l->id() )
+          {
+            QDomImplementation DomImplementation;
+            QDomDocumentType documentType = DomImplementation.createDocumentType( QStringLiteral( "qgis" ), QStringLiteral( "http://mrcc.com/qgis.dtd" ), QStringLiteral( "SYSTEM" ) );
+            QDomDocument document( documentType );
+            QDomElement element = mlNode.toElement();
+            document.appendChild( element );
+            QString str;
+            QTextStream stream( &str );
+            document.save( stream, 4 /*indent*/ );
+            l->setCustomProperty( QStringLiteral( "invalidLayerProperties" ), str );
+          }
+        }
+      }
+    }
+  }
+}
+
 QStringList QgsLayerTreeUtils::invisibleLayerList( QgsLayerTreeNode *node )
 {
   QStringList list;

diff --git a/src/core/layertree/qgslayertreeutils.h b/src/core/layertree/qgslayertreeutils.h
@@ -19,6 +19,7 @@
 #include <qnamespace.h>
 #include <QList>
 #include <QPair>
+#include <QDomNodeList>
 #include "qgis_core.h"
 
 class QDomElement;
@@ -58,9 +59,15 @@ class CORE_EXPORT QgsLayerTreeUtils
     //! Returns true if any of the layers is modified
     static bool layersModified( const QList<QgsLayerTreeLayer *> &layerNodes );
 
-    //! Remove layer nodes that refer to invalid layers
+    //! Removes layer nodes that refer to invalid layers
     static void removeInvalidLayers( QgsLayerTreeGroup *group );
 
+    /**
+     * Stores in a custom layer node property the layer properties XML information for an invalid layer
+     * \since 3.6
+     */
+    static void storeInvalidLayersProperties( QgsLayerTreeGroup *group, const QDomDocument *doc );
+
     //! Remove subtree of embedded groups and replaces it with a custom property embedded-visible-layers
     static void replaceChildrenOfEmbeddedGroups( QgsLayerTreeGroup *group );