Read/write relative paths to gpkg rasters in project (when enabled)

wonder-sk · wonder-sk · commit 89a80c1b550f · 2018-11-05T12:31:01.000+01:00
Routines in raster layer were not aware of "GDAL:filename:table" syntax
used for raster layers from GeoPackages so project files were storing
absolute paths even when relative paths should have been used.
diff --git a/src/core/raster/qgsrasterlayer.cpp b/src/core/raster/qgsrasterlayer.cpp
@@ -1646,6 +1646,32 @@ bool QgsRasterLayer::writeXml( QDomNode &layer_node,
   return writeSymbology( layer_node, document, errorMsg, context );
 }
 
+// TODO: this should ideally go to gdal provider (together with most of encodedSource() + decodedSource())
+static bool _parseGpkgColons( const QString &src, QString &filename, QString &tablename )
+{
+  // GDAL accepts the following input format:  GPKG:filename:table
+  // (GDAL won't accept quoted filename)
+
+  QStringList lst = src.split( ':' );
+  if ( lst.count() != 3 && lst.count() != 4 )
+    return false;
+
+  tablename = lst.last();
+  if ( lst.count() == 3 )
+  {
+    filename = lst[1];
+    return true;
+  }
+  else if ( lst.count() == 4 && lst[1].count() == 1 && ( lst[2][0] == '/' || lst[2][0] == '\\' ) )
+  {
+    // a bit of handling to make sure that filename C:\hello.gpkg is parsed correctly
+    filename = lst[1] + ":" + lst[2];
+    return true;
+  }
+  return false;
+}
+
+
 QString QgsRasterLayer::encodedSource( const QString &source, const QgsReadWriteContext &context ) const
 {
   QString src( source );
@@ -1668,6 +1694,17 @@ QString QgsRasterLayer::encodedSource( const QString &source, const QgsReadWrite
         handled = true;
       }
     }
+    else if ( src.startsWith( QLatin1String( "GPKG:" ) ) )
+    {
+      // GPKG:filename:table
+      QString filename, tablename;
+      if ( _parseGpkgColons( src, filename, tablename ) )
+      {
+        filename = context.pathResolver().writePath( filename );
+        src = QStringLiteral( "GPKG:%1:%2" ).arg( filename, tablename );
+        handled = true;
+      }
+    }
     else if ( src.startsWith( QLatin1String( "HDF4_SDS:" ) ) )
     {
       // HDF4_SDS:subdataset_type:file_name:subdataset_index
@@ -1817,6 +1854,17 @@ QString QgsRasterLayer::decodedSource( const QString &source, const QString &pro
           handled = true;
         }
       }
+      else if ( src.startsWith( QLatin1String( "GPKG:" ) ) )
+      {
+        // GPKG:filename:table
+        QString filename, tablename;
+        if ( _parseGpkgColons( src, filename, tablename ) )
+        {
+          filename = context.pathResolver().readPath( filename );
+          src = QStringLiteral( "GPKG:%1:%2" ).arg( filename, tablename );
+          handled = true;
+        }
+      }
       else if ( src.startsWith( QLatin1String( "HDF4_SDS:" ) ) )
       {
         // HDF4_SDS:subdataset_type:file_name:subdataset_index
