Add support for attribute renaming to OGR provider

Author: nyalldawson

src/providers/ogr/qgsogrprovider.cpp

@@ -1315,6 +1315,48 @@ bool QgsOgrProvider::deleteAttributes( const QgsAttributeIds &attributes )
 #endif
 }
 
+bool QgsOgrProvider::renameAttributes( const QgsFieldNameMap& renamedAttributes )
+{
+  if ( !doInitialActionsForEdition() )
+    return false;
+
+#if defined(GDAL_VERSION_NUM) && GDAL_VERSION_NUM >= 1900
+  QgsFieldNameMap::const_iterator renameIt = renamedAttributes.constBegin();
+  bool result = true;
+  for ( ; renameIt != renamedAttributes.constEnd(); ++renameIt )
+  {
+    int fieldIndex = renameIt.key();
+    if ( fieldIndex < 0 || fieldIndex >= mAttributeFields.count() )
+    {
+      pushError( tr( "Invalid attribute index" ) );
+      result = false;
+      continue;
+    }
+    if ( mAttributeFields.indexFromName( renameIt.value() ) >= 0 )
+    {
+      //field name already in use
+      pushError( tr( "Error renaming field %1: name '%2' already exists" ).arg( fieldIndex ).arg( renameIt.value() ) );
+      result = false;
+      continue;
+    }
+
+    //type does not matter, it will not be used
+    OGRFieldDefnH fld = OGR_Fld_Create( mEncoding->fromUnicode( renameIt.value() ), OFTReal );
+    if ( OGR_L_AlterFieldDefn( ogrLayer, fieldIndex, fld, ALTER_NAME_FLAG ) != OGRERR_NONE )
+    {
+      pushError( tr( "OGR error renaming field %1: %2" ).arg( fieldIndex ).arg( CPLGetLastErrorMsg() ) );
+      result = false;
+    }
+  }
+  loadFields();
+  return result;
+#else
+  Q_UNUSED( attributes );
+  pushError( tr( "Renaming fields is not supported prior to GDAL 1.9.0" ) );
+  return false;
+#endif
+}
+
 
 bool QgsOgrProvider::changeAttributeValues( const QgsChangedAttributesMap &attr_map )
 {
@@ -1724,6 +1766,11 @@ void QgsOgrProvider::computeCapabilities()
       ability |= DeleteAttributes;
     }
 
+    if ( mWriteAccessPossible && OGR_L_TestCapability( ogrLayer, "AlterFieldDefn" ) )
+    {
+      ability |= RenameAttributes;
+    }
+
 #if defined(OLCStringsAsUTF8)
     if ( !OGR_L_TestCapability( ogrLayer, OLCStringsAsUTF8 ) )
     {

src/providers/ogr/qgsogrprovider.h

@@ -137,19 +137,9 @@ class QgsOgrProvider : public QgsVectorDataProvider
     /** Deletes a feature*/
     virtual bool deleteFeatures( const QgsFeatureIds & id ) override;
 
-    /**
-     * Adds new attributes
-     * @param attributes list of new attributes
-     * @return true in case of success and false in case of failure
-     */
     virtual bool addAttributes( const QList<QgsField> &attributes ) override;
-
-    /**
-     * Deletes existing attributes
-     * @param attributes a set containing names of attributes
-     * @return true in case of success and false in case of failure
-     */
     virtual bool deleteAttributes( const QgsAttributeIds &attributes ) override;
+    virtual bool renameAttributes( const QgsFieldNameMap& renamedAttributes ) override;
 
     /** Changes attribute values of existing features */
     virtual bool changeAttributeValues( const QgsChangedAttributesMap &attr_map ) override;

tests/src/python/test_provider_shapefile.py

@@ -294,5 +294,51 @@ def testreloadData(self):
         # And now check that fields are up-to-date
         self.assertEquals(len(vl1.fields()), len(vl2.fields()))
 
+    def testRenameAttributes(self):
+        ''' Test renameAttributes() '''
+
+        tmpdir = tempfile.mkdtemp()
+        self.dirs_to_cleanup.append(tmpdir)
+        srcpath = os.path.join(TEST_DATA_DIR, 'provider')
+        for file in glob.glob(os.path.join(srcpath, 'shapefile.*')):
+            shutil.copy(os.path.join(srcpath, file), tmpdir)
+        datasource = os.path.join(tmpdir, 'shapefile.shp')
+
+        vl = QgsVectorLayer(u'{}|layerid=0'.format(datasource), u'test', u'ogr')
+        provider = vl.dataProvider()
+
+        # bad rename
+        self.assertFalse(provider.renameAttributes({-1: 'not_a_field'}))
+        self.assertFalse(provider.renameAttributes({100: 'not_a_field'}))
+        # already exists
+        self.assertFalse(provider.renameAttributes({2: 'cnt'}))
+
+        # rename one field
+        self.assertTrue(provider.renameAttributes({2: 'newname'}))
+        self.assertEqual(provider.fields().at(2).name(), 'newname')
+        vl.updateFields()
+        fet = next(vl.getFeatures())
+        self.assertEqual(fet.fields()[2].name(), 'newname')
+
+        # rename two fields
+        self.assertTrue(provider.renameAttributes({2: 'newname2', 3: 'another'}))
+        self.assertEqual(provider.fields().at(2).name(), 'newname2')
+        self.assertEqual(provider.fields().at(3).name(), 'another')
+        vl.updateFields()
+        fet = next(vl.getFeatures())
+        self.assertEqual(fet.fields()[2].name(), 'newname2')
+        self.assertEqual(fet.fields()[3].name(), 'another')
+
+        # close file and reopen, then recheck to confirm that changes were saved to file
+        del vl
+        vl = None
+        vl = QgsVectorLayer(u'{}|layerid=0'.format(datasource), u'test', u'ogr')
+        provider = vl.dataProvider()
+        self.assertEqual(provider.fields().at(2).name(), 'newname2')
+        self.assertEqual(provider.fields().at(3).name(), 'another')
+        fet = next(vl.getFeatures())
+        self.assertEqual(fet.fields()[2].name(), 'newname2')
+        self.assertEqual(fet.fields()[3].name(), 'another')
+
 if __name__ == '__main__':
     unittest.main()

tests/src/python/test_provider_tabfile.py

@@ -13,7 +13,7 @@
 __revision__ = '$Format:%H$'
 
 import os
-
+import tempfile
 from qgis.core import QgsVectorLayer, QgsFeatureRequest, QgsVectorDataProvider
 from qgis.PyQt.QtCore import QDate, QTime, QDateTime, QVariant
 from qgis.testing import (
@@ -22,6 +22,9 @@
 )
 import osgeo.gdal
 from utilities import unitTestDataPath
+import tempfile
+import shutil
+import glob
 
 start_app()
 TEST_DATA_DIR = unitTestDataPath()
@@ -31,6 +34,18 @@
 
 class TestPyQgsTabfileProvider(unittest.TestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        """Run before all tests"""
+        cls.basetestpath = tempfile.mkdtemp()
+        cls.dirs_to_cleanup = [cls.basetestpath]
+
+    @classmethod
+    def tearDownClass(cls):
+        """Run after all tests"""
+        for dirname in cls.dirs_to_cleanup:
+            shutil.rmtree(dirname, True)
+
     def testDateTimeFormats(self):
         # check that date and time formats are correctly interpreted
         basetestfile = os.path.join(TEST_DATA_DIR, 'tab_file.tab')
@@ -75,5 +90,6 @@ def testUpdateMode(self):
         self.assertEquals(vl.dataProvider().property("_debug_open_mode"), "read-only")
         self.assertTrue(vl.dataProvider().isValid())
 
+
 if __name__ == '__main__':
     unittest.main()