Implement clear action

python/core/qgsauxiliarystorage.sip

@@ -92,6 +92,15 @@ class QgsAuxiliaryLayer : QgsVectorLayer
 
 
 
+    bool clear();
+%Docstring
+ Deletes all features from the layer. Changes are automatically committed
+ and the layer remains editable.
+
+ :return: true if changes are committed without error, false otherwise.
+ :rtype: bool
+%End
+
     QgsVectorLayerJoinInfo joinInfo() const;
 %Docstring
  Returns information to use for joining with primary key and so on.

src/app/qgsvectorlayerproperties.cpp

@@ -84,6 +84,7 @@ QgsVectorLayerProperties::QgsVectorLayerProperties(
   , mLayer( lyr )
   , mOriginalSubsetSQL( lyr->subsetString() )
   , mAuxiliaryLayerActionNew( nullptr )
+  , mAuxiliaryLayerActionClear( nullptr )
 {
   setupUi( this );
   connect( mLayerOrigNameLineEdit, &QLineEdit::textEdited, this, &QgsVectorLayerProperties::mLayerOrigNameLineEdit_textEdited );
@@ -361,6 +362,10 @@ QgsVectorLayerProperties::QgsVectorLayerProperties(
   menu->addAction( mAuxiliaryLayerActionNew );
   connect( mAuxiliaryLayerActionNew, &QAction::triggered, this, &QgsVectorLayerProperties::onAuxiliaryLayerNew );
 
+  mAuxiliaryLayerActionClear = new QAction( tr( "Clear" ), this );
+  menu->addAction( mAuxiliaryLayerActionClear );
+  connect( mAuxiliaryLayerActionClear, &QAction::triggered, this, &QgsVectorLayerProperties::onAuxiliaryLayerClear );
+
   mAuxiliaryStorageActions->setMenu( menu );
 
   updateAuxiliaryStoragePage();
@@ -1554,3 +1559,24 @@ void QgsVectorLayerProperties::onAuxiliaryLayerNew()
     updateAuxiliaryStoragePage( true );
   }
 }
+
+void QgsVectorLayerProperties::onAuxiliaryLayerClear()
+{
+  QgsAuxiliaryLayer *alayer = mLayer->auxiliaryLayer();
+
+  if ( !alayer )
+    return;
+
+  const QString msg = tr( "Are you sure you want to clear auxiliary data for %1" ).arg( mLayer->name() );
+  QMessageBox::StandardButton reply;
+  reply = QMessageBox::question( this, "Clear auxiliary data", msg, QMessageBox::Yes | QMessageBox::No );
+
+  if ( reply == QMessageBox::Yes )
+  {
+    QApplication::setOverrideCursor( Qt::WaitCursor );
+    alayer->clear();
+    QApplication::restoreOverrideCursor();
+    updateAuxiliaryStoragePage( true );
+    mLayer->triggerRepaint();
+  }
+}

src/app/qgsvectorlayerproperties.h

@@ -157,6 +157,7 @@ class APP_EXPORT QgsVectorLayerProperties : public QgsOptionsDialogBase, private
     void updateFieldsPropertiesDialog();
 
     void onAuxiliaryLayerNew();
+    void onAuxiliaryLayerClear();
 
   private:
 
@@ -222,6 +223,7 @@ class APP_EXPORT QgsVectorLayerProperties : public QgsOptionsDialogBase, private
     QgsMetadataWidget *mMetadataWidget = nullptr;
 
     QAction *mAuxiliaryLayerActionNew;
+    QAction *mAuxiliaryLayerActionClear;
 
   private slots:
     void openPanel( QgsPanelWidget *panel );

src/core/qgsauxiliarystorage.cpp

@@ -115,6 +115,14 @@ void QgsAuxiliaryField::init( const QgsPropertyDefinition &def )
   }
 }
 
+bool QgsAuxiliaryLayer::clear()
+{
+  bool rc = deleteFeatures( allFeatureIds() );
+  commitChanges();
+  startEditing();
+  return rc;
+}
+
 QString QgsAuxiliaryField::name( const QgsPropertyDefinition &def, bool joined )
 {
   QString origin;

src/core/qgsauxiliarystorage.h

@@ -122,6 +122,14 @@ class CORE_EXPORT QgsAuxiliaryLayer : public QgsVectorLayer
 
     QgsAuxiliaryLayer &operator=( QgsAuxiliaryLayer const &rhs ) = delete;
 
+    /**
+     * Deletes all features from the layer. Changes are automatically committed
+     * and the layer remains editable.
+     *
+     * \returns true if changes are committed without error, false otherwise.
+     */
+    bool clear();
+
     /**
      * Returns information to use for joining with primary key and so on.
      */