[GRASS] prevent changing attributes of different layer

Author: blazek

src/providers/grass/qgsgrassfeatureiterator.cpp

@@ -649,6 +649,11 @@ int QgsGrassFeatureIterator::catFromFid( QgsFeatureId fid )
   return fid % 1000000000;
 }
 
+QVariant QgsGrassFeatureIterator::nonEditableValue( int layerNumber )
+{
+  return tr( "<not editable (layer %1)>" ).arg( layerNumber );
+}
+
 void QgsGrassFeatureIterator::setFeatureAttributes( int cat, QgsFeature *feature, QgsGrassVectorMap::TopoSymbol symbol )
 {
   QgsDebugMsgLevel( QString( "setFeatureAttributes cat = %1" ).arg( cat ), 3 );
@@ -701,15 +706,14 @@ void QgsGrassFeatureIterator::setFeatureAttributes( int cat, QgsFeature *feature
     }
     else
     {
-      // TODO: use real layer keyColumn(), but to get it the layer must be first opened and attributes loaded
-      int keyColumn = 0;
-      if ( *iter == keyColumn )
+      // We are setting cat of different layer in cat column of this layer
+      if ( *iter == mSource->mLayer->keyColumn() )
       {
         value = QVariant( cat );
       }
       else
       {
-        value = tr( "<not editable (layer %1)>" ).arg( layerNumber );
+        value = nonEditableValue( layerNumber );
       }
     }
     QgsDebugMsgLevel( QString( "iter = %1 value = %2" ).arg( *iter ).arg( value.toString() ), 3 );

src/providers/grass/qgsgrassfeatureiterator.h

@@ -96,6 +96,9 @@ class GRASS_LIB_EXPORT QgsGrassFeatureIterator : public QObject, public QgsAbstr
     // Get GRASS cat from QGIS fid
     static int catFromFid( QgsFeatureId fid );
 
+    // get attribute value to be used in different layer when it is edited
+    static QVariant nonEditableValue( int layerNumber );
+
   public slots:
     /** Cancel iterator, iterator will be closed on next occasion, probably when next getFeature() gets called.
      * This function can be called directly from other threads (setting bool is atomic) */

src/providers/grass/qgsgrassprovider.cpp

@@ -1709,8 +1709,33 @@ void QgsGrassProvider::onAttributeValueChanged( QgsFeatureId fid, int idx, const
 {
   QgsDebugMsg( QString( "fid = %1 idx = %2 value = %3" ).arg( fid ).arg( idx ).arg( value.toString() ) );
 
-  int oldLid = QgsGrassFeatureIterator::lidFromFid( fid );
+  int layerField = QgsGrassFeatureIterator::layerFromFid( fid );
   int cat = QgsGrassFeatureIterator::catFromFid( fid );
+  QgsDebugMsg( QString( "layerField = %1" ).arg( layerField ) );
+
+  if ( !FID_IS_NEW( fid ) && layerField != mLayerField )
+  {
+    QgsDebugMsg( "changing attributes in different layer is not allowed" );
+    // reset the value
+    QgsChangedAttributesMap &changedAttributes = const_cast<QgsChangedAttributesMap &>( mEditBuffer->changedAttributeValues() );
+    if ( idx == mLayer->keyColumn() )
+    {
+      // should not happen because cat field is not editable
+      changedAttributes[fid][idx] = cat;
+    }
+    else
+    {
+      changedAttributes[fid][idx] = QgsGrassFeatureIterator::nonEditableValue( layerField );
+    }
+    // update table
+    // TODO: This would be too slow with buld update (field calculator for example), causing update
+    // of the whole table after each change. How to update single row?
+    //emit dataChanged();
+    return;
+  }
+
+  int oldLid = QgsGrassFeatureIterator::lidFromFid( fid );
+
   int realLine = oldLid;
   int realCat = cat;
   if ( mLayer->map()->newLids().contains( oldLid ) ) // if it was changed already