Adds delete layer context action to ogr and geopackage items

TODO: decide what to do if the layer to be deleted was
added to the canvas: block the deletion?

Current implementation just ignores the fact with
no apparent serious consequences beside that
obviously the layer is not drawn anymore.

Author: elpaso

src/providers/ogr/qgsgeopackagedataitems.cpp

@@ -20,13 +20,16 @@
 #include "qgsproject.h"
 #include "qgsvectorlayer.h"
 #include "qgsrasterlayer.h"
+#include "qgsogrprovider.h"
 #include "qgsnewgeopackagelayerdialog.h"
 
 #include <QAction>
 #include <QMessageBox>
 #include <QFileDialog>
 #include <QInputDialog>
 
+QGISEXTERN bool deleteLayer( const QString &uri, const QString &errCause );
+
 QgsDataItem *QgsGeoPackageDataItemProvider::createDataItem( const QString &path, QgsDataItem *parentItem )
 {
   QgsDebugMsg( "path = " + path );
@@ -327,7 +330,6 @@ void QgsGeoPackageConnectionItem::addTable()
 QList<QAction *> QgsGeoPackageAbstractLayerItem::actions()
 {
   QList<QAction *> lst;
-
   // TODO: delete layer when the provider supports it (not currently implemented)
   return lst;
 }
@@ -352,3 +354,39 @@ QgsGeoPackageRasterLayerItem::QgsGeoPackageRasterLayerItem( QgsDataItem *parent,
 {
 
 }
+
+
+
+#ifdef HAVE_GUI
+QList<QAction *> QgsGeoPackageVectorLayerItem::actions()
+{
+  QList<QAction *> lst = QgsGeoPackageAbstractLayerItem::actions();
+  QAction *actionDeleteLayer = new QAction( tr( "Delete %1" ).arg( mName ), this );
+  connect( actionDeleteLayer, &QAction::triggered, this, &QgsGeoPackageVectorLayerItem::deleteLayer );
+  lst.append( actionDeleteLayer );
+  return lst;
+}
+
+
+void QgsGeoPackageVectorLayerItem::deleteLayer()
+{
+  if ( QMessageBox::question( nullptr, QObject::tr( "Delete Layer" ),
+                              QObject::tr( "Are you sure you want to delete %1?" ).arg( mName ),
+                              QMessageBox::Yes | QMessageBox::No, QMessageBox::No ) != QMessageBox::Yes )
+    return;
+
+  QString errCause;
+  bool res = ::deleteLayer( mUri, errCause );
+  if ( !res )
+  {
+    QMessageBox::warning( nullptr, tr( "Delete Layer" ), errCause );
+  }
+  else
+  {
+    QMessageBox::information( nullptr, tr( "Delete Layer" ), tr( "Layer deleted successfully." ) );
+    if ( mParent )
+      mParent->refresh();
+  }
+}
+#endif
+

src/providers/ogr/qgsgeopackagedataitems.h

@@ -49,7 +49,11 @@ class QgsGeoPackageVectorLayerItem : public QgsGeoPackageAbstractLayerItem
     Q_OBJECT
   public:
     QgsGeoPackageVectorLayerItem( QgsDataItem *parent, QString name, QString path, QString uri, LayerType layerType );
-
+#ifdef HAVE_GUI
+    QList<QAction *> actions() override;
+  public slots:
+    void deleteLayer();
+#endif
 };
 
 

src/providers/ogr/qgsogrdataitems.cpp

@@ -22,6 +22,7 @@
 #include <QFileInfo>
 #include <QTextStream>
 #include <QAction>
+#include <QMessageBox>
 
 #include <ogr_srs_api.h>
 #include <cpl_error.h>
@@ -31,6 +32,8 @@
 QGISEXTERN QStringList fileExtensions();
 QGISEXTERN QStringList wildcards();
 
+QGISEXTERN bool deleteLayer( const QString &uri, const QString &errCause );
+
 
 QgsOgrLayerItem::QgsOgrLayerItem( QgsDataItem *parent,
                                   QString name, QString path, QString uri, LayerType layerType )
@@ -56,6 +59,7 @@ QgsOgrLayerItem::QgsOgrLayerItem( QgsDataItem *parent,
   }
 }
 
+
 bool QgsOgrLayerItem::setCrs( const QgsCoordinateReferenceSystem &crs )
 {
   if ( !( mCapabilities & SetCrs ) )
@@ -110,6 +114,38 @@ QString QgsOgrLayerItem::layerName() const
     return info.completeBaseName();
 }
 
+#ifdef HAVE_GUI
+QList<QAction *> QgsOgrLayerItem::actions()
+{
+  QList<QAction *> lst;
+  QAction *actionDeleteLayer = new QAction( tr( "Delete %1" ).arg( mName ), this );
+  connect( actionDeleteLayer, &QAction::triggered, this, &QgsOgrLayerItem::deleteLayer );
+  lst.append( actionDeleteLayer );
+  return lst;
+}
+
+void QgsOgrLayerItem::deleteLayer()
+{
+  if ( QMessageBox::question( nullptr, QObject::tr( "Delete Layer" ),
+                              QObject::tr( "Are you sure you want to delete %1?" ).arg( mName ),
+                              QMessageBox::Yes | QMessageBox::No, QMessageBox::No ) != QMessageBox::Yes )
+    return;
+
+  QString errCause;
+  bool res = ::deleteLayer( mUri, errCause );
+  if ( !res )
+  {
+    QMessageBox::warning( nullptr, tr( "Delete Layer" ), errCause );
+  }
+  else
+  {
+    QMessageBox::information( nullptr, tr( "Delete Layer" ), tr( "Layer deleted successfully." ) );
+    if ( mParent )
+      mParent->refresh();
+  }
+}
+#endif
+
 // -------
 
 static QgsOgrLayerItem *dataItemForLayer( QgsDataItem *parentItem, QString name, QString path, OGRDataSourceH hDataSource, int layerId )

src/providers/ogr/qgsogrdataitems.h

@@ -29,6 +29,12 @@ class QgsOgrLayerItem : public QgsLayerItem
     bool setCrs( const QgsCoordinateReferenceSystem &crs ) override;
 
     QString layerName() const override;
+
+#ifdef HAVE_GUI
+    QList<QAction *> actions() override;
+  public slots:
+    void deleteLayer();
+#endif
 };
 
 

src/providers/ogr/qgsogrprovider.cpp

@@ -4297,3 +4297,76 @@ QGISEXTERN void cleanupProvider()
   // NOTE: QgsApplication takes care of
   // calling OGRCleanupAll();
 }
+
+
+
+QGISEXTERN bool deleteLayer( const QString &uri, QString &errCause )
+{
+  bool isSubLayer;
+  int layerIndex;
+  QString layerName;
+  QString subsetString;
+  OGRwkbGeometryType ogrGeometryType;
+  QString filePath = AnalyzeURI( uri,
+                                 isSubLayer,
+                                 layerIndex,
+                                 layerName,
+                                 subsetString,
+                                 ogrGeometryType );
+
+  OGRDataSourceH hDS = GDALOpenEx( filePath.toLocal8Bit().data(), GDAL_OF_RASTER | GDAL_OF_VECTOR | GDAL_OF_UPDATE, NULL, NULL, NULL );
+  if ( hDS  && ( ! layerName.isEmpty() || layerIndex != -1 ) )
+  {
+    if ( layerIndex == -1 )
+    {
+      for ( int i = 0; i < GDALDatasetGetLayerCount( hDS ); i++ )
+      {
+        OGRLayerH hL = GDALDatasetGetLayer( hDS, i );
+        if ( layerName == QString( OGR_L_GetName( hL ) ) )
+        {
+          layerIndex = i;
+        }
+      }
+    }
+    OGRErr error = GDALDatasetDeleteLayer( hDS, layerIndex );
+    switch ( error )
+    {
+      case OGRERR_NOT_ENOUGH_DATA:
+        errCause = QStringLiteral( "Not enough data to deserialize" );
+        break;
+      case OGRERR_NOT_ENOUGH_MEMORY:
+        errCause = QStringLiteral( "Not enough memory" );
+        break;
+      case OGRERR_UNSUPPORTED_GEOMETRY_TYPE:
+        errCause = QStringLiteral( "Unsupported geometry type" );
+        break;
+      case OGRERR_UNSUPPORTED_OPERATION:
+        errCause = QStringLiteral( "Unsupported operation" );
+        break;
+      case OGRERR_CORRUPT_DATA:
+        errCause = QStringLiteral( "Corrupt data" );
+        break;
+      case OGRERR_FAILURE:
+        errCause = QStringLiteral( "Failure" );
+        break;
+      case OGRERR_UNSUPPORTED_SRS:
+        errCause = QStringLiteral( "Unsupported SRS" );
+        break;
+      case OGRERR_INVALID_HANDLE:
+        errCause = QStringLiteral( "Invalid handle" );
+        break;
+      case OGRERR_NON_EXISTING_FEATURE:
+        errCause = QStringLiteral( "Non existing feature" );
+        break;
+      default:
+      case OGRERR_NONE:
+        errCause = QStringLiteral( "Success" );
+        break;
+    }
+    errCause = QStringLiteral( "OGR result code: %s" ).arg( errCause );
+    return error == OGRERR_NONE;
+  }
+  // This should never happen:
+  errCause = QStringLiteral( "Layer not found: %s" ).arg( uri );
+  return false;
+}