delete layer action only on items that have capability "delete"

check if the item with the menu has this capability and only handle the selected items with this capabiltiy

Author: signedav

python/core/auto_generated/qgsdataitem.sip.in

@@ -201,6 +201,7 @@ Items that return valid URI will be returned in mime data when dragging a select
       Fast,
       Collapse,
       Rename,
+      Delete,
     };
     typedef QFlags<QgsDataItem::Capability> Capabilities;
 
@@ -312,11 +313,6 @@ Sets a custom sorting ``key`` for the item.
     void moveToThread( QThread *targetThread );
 %Docstring
 Move object and all its descendants to thread
-%End
-
-    virtual bool deleteLayer();
-%Docstring
-Delete this layer item
 %End
 
   protected:
@@ -490,6 +486,11 @@ Returns the string representation of the given ``layerType``
 Returns the icon name of the given ``layerType``
 
 .. versionadded:: 3
+%End
+
+    virtual bool deleteLayer();
+%Docstring
+Delete this layer item
 %End
 
   protected:

src/app/browser/qgsinbuiltdataitemproviders.cpp

@@ -366,14 +366,24 @@ void QgsLayerItemGuiProvider::populateContextMenu( QgsDataItem *item, QMenu *men
   } );
   menu->addAction( addAction );
 
-  const QString deleteText = selectedItems.count() == 1 ? tr( "Delete Layer" )
-                             : tr( "Delete Selected Layers" );
-  QAction *deleteAction = new QAction( deleteText, menu );
-  connect( deleteAction, &QAction::triggered, this, [ = ]
+  if ( item->capabilities2() & QgsDataItem::Delete )
   {
-    deleteLayers( selectedItems );
-  } );
-  menu->addAction( deleteAction );
+    QList<QgsLayerItem *> selectedDeletableItems;
+    for ( QgsDataItem *selectedItem : selectedItems )
+    {
+      if ( qobject_cast<QgsLayerItem *>( selectedItem ) && ( selectedItem->capabilities2() & QgsDataItem::Delete ) )
+        selectedDeletableItems.append( qobject_cast<QgsLayerItem *>( selectedItem ) );
+    }
+
+    const QString deleteText = selectedDeletableItems.count() == 1 ? tr( "Delete Layer" )
+                               : tr( "Delete Selected Layers" );
+    QAction *deleteAction = new QAction( deleteText, menu );
+    connect( deleteAction, &QAction::triggered, this, [ = ]
+    {
+      deleteLayers( selectedDeletableItems );
+    } );
+    menu->addAction( deleteAction );
+  }
 
   QAction *propertiesAction = new QAction( tr( "Layer Properties…" ), menu );
   connect( propertiesAction, &QAction::triggered, this, [ = ]
@@ -442,9 +452,9 @@ void QgsLayerItemGuiProvider::addLayersFromItems( const QList<QgsDataItem *> &it
     QgisApp::instance()->handleDropUriList( layerUriList );
 }
 
-void QgsLayerItemGuiProvider::deleteLayers( const QList<QgsDataItem *> &items )
+void QgsLayerItemGuiProvider::deleteLayers( const QList<QgsLayerItem *> &items )
 {
-  for ( QgsDataItem *item : items )
+  for ( QgsLayerItem *item : items )
   {
     if ( !item->deleteLayer() )
       QMessageBox::information( QgisApp::instance(), tr( "Delete Layer" ), tr( "Item Layer %1 cannot be deleted." ).arg( item->name() ) );

src/app/browser/qgsinbuiltdataitemproviders.h

@@ -100,7 +100,7 @@ class QgsLayerItemGuiProvider : public QObject, public QgsDataItemGuiProvider
 
     void addLayersFromItems( const QList<QgsDataItem *> &items );
     void showPropertiesForItem( QgsLayerItem *item );
-    void deleteLayers( const QList<QgsDataItem *> &items );
+    void deleteLayers( const QList<QgsLayerItem *> &items );
 
 };
 

src/core/qgsdataitem.cpp

@@ -219,11 +219,6 @@ void QgsDataItem::moveToThread( QThread *targetThread )
   QObject::moveToThread( targetThread );
 }
 
-bool QgsDataItem::deleteLayer()
-{
-  return false;
-}
-
 QIcon QgsDataItem::icon()
 {
   if ( state() == Populating && sPopulatingIcon )
@@ -706,6 +701,11 @@ QString QgsLayerItem::iconName( QgsLayerItem::LayerType layerType )
   }
 }
 
+bool QgsLayerItem::deleteLayer()
+{
+  return false;
+}
+
 bool QgsLayerItem::equal( const QgsDataItem *other )
 {
   //QgsDebugMsg ( mPath + " x " + other->mPath );

src/core/qgsdataitem.h

@@ -210,8 +210,9 @@ class CORE_EXPORT QgsDataItem : public QObject
       SetCrs            = 1 << 0, //!< Can set CRS on layer or group of layers
       Fertile           = 1 << 1, //!< Can create children. Even items without this capability may have children, but cannot create them, it means that children are created by item ancestors.
       Fast              = 1 << 2, //!< CreateChildren() is fast enough to be run in main thread when refreshing items, most root items (wms,wfs,wcs,postgres...) are considered fast because they are reading data only from QgsSettings
-      Collapse          = 1 << 3,  //!< The collapse/expand status for this items children should be ignored in order to avoid undesired network connections (wms etc.)
+      Collapse          = 1 << 3, //!< The collapse/expand status for this items children should be ignored in order to avoid undesired network connections (wms etc.)
       Rename            = 1 << 4, //!< Item can be renamed
+      Delete            = 1 << 5, //!< Item can be deleted
     };
     Q_DECLARE_FLAGS( Capabilities, Capability )
 
@@ -323,9 +324,6 @@ class CORE_EXPORT QgsDataItem : public QObject
     //! Move object and all its descendants to thread
     void moveToThread( QThread *targetThread );
 
-    //! Delete this layer item
-    virtual bool deleteLayer();
-
   protected:
     virtual void populate( const QVector<QgsDataItem *> &children );
 
@@ -508,6 +506,9 @@ class CORE_EXPORT QgsLayerItem : public QgsDataItem
      */
     static QString iconName( LayerType layerType );
 
+    //! Delete this layer item
+    virtual bool deleteLayer();
+
   protected:
 
     //! The provider key

src/providers/mssql/qgsmssqldataitems.cpp

@@ -561,6 +561,7 @@ QgsMssqlLayerItem::QgsMssqlLayerItem( QgsDataItem *parent, const QString &name,
   : QgsLayerItem( parent, name, path, QString(), layerType, QStringLiteral( "mssql" ) )
   , mLayerProperty( layerProperty )
 {
+  mCapabilities |= Delete;
   mUri = createUri();
   setState( Populated );
 }

src/providers/ogr/qgsgeopackagedataitems.cpp

@@ -699,6 +699,7 @@ bool QgsGeoPackageConnectionItem::equal( const QgsDataItem *other )
 QgsGeoPackageAbstractLayerItem::QgsGeoPackageAbstractLayerItem( QgsDataItem *parent, const QString &name, const QString &path, const QString &uri, QgsLayerItem::LayerType layerType, const QString &providerKey )
   : QgsLayerItem( parent, name, path, uri, layerType, providerKey )
 {
+  mCapabilities |= Delete;
   mToolTip = uri;
   setState( Populated ); // no children are expected
 }

src/providers/postgres/qgspostgresdataitems.cpp

@@ -296,6 +296,7 @@ QgsPGLayerItem::QgsPGLayerItem( QgsDataItem *parent, const QString &name, const
   : QgsLayerItem( parent, name, path, QString(), layerType, QStringLiteral( "postgres" ) )
   , mLayerProperty( layerProperty )
 {
+  mCapabilities |= Delete;
   mUri = createUri();
   setState( Populated );
   Q_ASSERT( mLayerProperty.size() == 1 );

src/providers/spatialite/qgsspatialitedataitems.cpp

@@ -37,6 +37,7 @@ QGISEXTERN bool deleteLayer( const QString &dbPath, const QString &tableName, QS
 QgsSLLayerItem::QgsSLLayerItem( QgsDataItem *parent, const QString &name, const QString &path, const QString &uri, LayerType layerType )
   : QgsLayerItem( parent, name, path, uri, layerType, QStringLiteral( "spatialite" ) )
 {
+  mCapabilities |= Delete;
   setState( Populated ); // no children are expected
 }