Geopackge bugfix: also show single raster layers

The previous implementation only showed subdatasets
while single raster were skipped.

Now the single rasters are also showed and the name
is retrieved from GDAL metadata IDENTIFIER.

The gpkg table name is used to delete the table.

src/providers/ogr/qgsgeopackagedataitems.cpp

@@ -26,6 +26,7 @@
 #include "qgsnewgeopackagelayerdialog.h"
 #include "qgsmessageoutput.h"
 #include "qgsvectorlayerexporter.h"
+#include "gdal.h"
 
 #include <QAction>
 #include <QMessageBox>
@@ -231,14 +232,51 @@ QVector<QgsDataItem *> QgsGeoPackageConnectionItem::createChildren()
   }
   // Raster layers
   QgsRasterLayer rlayer( mPath, QStringLiteral( "gdal_tmp" ), QStringLiteral( "gdal" ), false );
-  Q_FOREACH ( const QString &uri, rlayer.dataProvider()->subLayers( ) )
+  if ( rlayer.dataProvider()->subLayers( ).size() > 0 )
   {
-    QStringList pieces = uri.split( ':' );
-    QString name = pieces.value( pieces.length() - 1 );
-    QgsDebugMsgLevel( QStringLiteral( "Adding GeoPackage Raster item %1 %2 %3" ).arg( name, uri ), 3 );
-    QgsGeoPackageRasterLayerItem *item = new QgsGeoPackageRasterLayerItem( this, name, mPath, uri );
-    children.append( item );
+    Q_FOREACH ( const QString &uri, rlayer.dataProvider()->subLayers( ) )
+    {
+      QStringList pieces = uri.split( ':' );
+      QString name = pieces.value( pieces.length() - 1 );
+      QgsDebugMsgLevel( QStringLiteral( "Adding GeoPackage Raster item %1 %2 %3" ).arg( name, uri ), 3 );
+      QgsGeoPackageRasterLayerItem *item = new QgsGeoPackageRasterLayerItem( this, name, mPath, uri );
+      children.append( item );
+    }
+  }
+  else if ( rlayer.isValid( ) )
+  {
+    // Get the identifier
+    GDALAllRegister();
+    // do not print errors, but write to debug
+    CPLPushErrorHandler( CPLQuietErrorHandler );
+    CPLErrorReset();
+    GDALDatasetH hDS = GDALOpen( mPath.toUtf8().constData(), GA_ReadOnly );
+    CPLPopErrorHandler();
+
+    if ( ! hDS )
+    {
+      QgsDebugMsg( QString( "GDALOpen error # %1 : %2 " ).arg( CPLGetLastErrorNo() ).arg( CPLGetLastErrorMsg() ) );
 
+    }
+    else
+    {
+      QString uri( QStringLiteral( "GPKG:%1" ).arg( mPath ) );
+      QString name = GDALGetMetadataItem( hDS, "IDENTIFIER", NULL );
+      GDALClose( hDS );
+      // Fallback: will not be able to delete the table
+      if ( name.isEmpty() )
+      {
+        name = QFileInfo( mPath ).fileName();
+      }
+      else
+      {
+        uri += QStringLiteral( ":%1" ).arg( name );
+      }
+
+      QgsDebugMsgLevel( QStringLiteral( "Adding GeoPackage Raster item %1 %2 %3" ).arg( name, mPath ), 3 );
+      QgsGeoPackageRasterLayerItem *item = new QgsGeoPackageRasterLayerItem( this, name, mPath, uri );
+      children.append( item );
+    }
   }
   return children;
 
@@ -531,7 +569,7 @@ bool QgsGeoPackageRasterLayerItem::executeDeleteLayer( QString &errCause )
       QString baseUri = pieces.at( 1 );
       QString layerName = pieces.at( 2 );
       sqlite3 *handle;
-      int status = sqlite3_open_v2( baseUri.toLocal8Bit().data(), &handle, SQLITE_OPEN_READWRITE, NULL );
+      int status = sqlite3_open_v2( baseUri.toUtf8().constData(), &handle, SQLITE_OPEN_READWRITE, NULL );
       if ( status != SQLITE_OK )
       {
         errCause = sqlite3_errmsg( handle );
@@ -547,7 +585,7 @@ bool QgsGeoPackageRasterLayerItem::executeDeleteLayer( QString &errCause )
                               "DELETE FROM gpkg_tile_matrix_set WHERE table_name = '%1';" ).arg( layerName );
         status = sqlite3_exec(
                    handle,                              /* An open database */
-                   sql.toLocal8Bit().data(),            /* SQL to be evaluated */
+                   sql.toUtf8().constData(),            /* SQL to be evaluated */
                    NULL,                                /* Callback function */
                    NULL,                                /* 1st argument to callback */
                    &errmsg                              /* Error msg written here */