Use metadata method to retrieve Shapefile encoding on GDAL 3.1+ builds

Avoids code duplication, correct behavior with vsi* sources
qgis · Feb 12, 2020 · 54eba4a · 54eba4a
1 parent 5c84d7f
commit 54eba4a
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Showing 6 changed files with 40 additions and 27 deletions.
diff --git a/src/analysis/processing/qgsalgorithmshpencodinginfo.cpp b/src/analysis/processing/qgsalgorithmshpencodinginfo.cpp
@@ -75,26 +75,19 @@ void QgsShapefileEncodingInfoAlgorithm::initAlgorithm( const QVariantMap & )
 bool QgsShapefileEncodingInfoAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
 {
   const QString path = parameterAsFile( parameters, QStringLiteral( "INPUT" ), context );
-  if ( !QFile::exists( path ) )
-  {
-    feedback->reportError( QObject::tr( "Input Shapefile %1 does not exist" ).arg( path ) );
-    return false;
-  }
+
+  mCpgEncoding = QgsOgrUtils::readShapefileEncodingFromCpg( path );
+  if ( mCpgEncoding.isEmpty() )
+    feedback->pushInfo( QObject::tr( "No encoding information present in CPG file" ) );
+  else
+    feedback->pushInfo( QObject::tr( "Detected encoding from CPG file: %1" ).arg( mCpgEncoding ) );
+
+  mLdidEncoding = QgsOgrUtils::readShapefileEncodingFromLdid( path );
+  if ( mLdidEncoding.isEmpty() )
+    feedback->pushInfo( QObject::tr( "No encoding information present in DBF LDID header" ) );
   else
-  {
-    mCpgEncoding = QgsOgrUtils::readShapefileEncodingFromCpg( path );
-    if ( mCpgEncoding.isEmpty() )
-      feedback->pushInfo( QObject::tr( "No encoding information present in CPG file" ) );
-    else
-      feedback->pushInfo( QObject::tr( "Detected encoding from CPG file: %1" ).arg( mCpgEncoding ) );
-
-    mLdidEncoding = QgsOgrUtils::readShapefileEncodingFromLdid( path );
-    if ( mLdidEncoding.isEmpty() )
-      feedback->pushInfo( QObject::tr( "No encoding information present in DBF LDID header" ) );
-    else
-      feedback->pushInfo( QObject::tr( "Detected encoding from DBF LDID header: %1" ).arg( mLdidEncoding ) );
-
-  }
+    feedback->pushInfo( QObject::tr( "Detected encoding from DBF LDID header: %1" ).arg( mLdidEncoding ) );
+
   return true;
 }
 

diff --git a/src/core/providers/ogr/qgsogrprovider.cpp b/src/core/providers/ogr/qgsogrprovider.cpp
@@ -4537,7 +4537,15 @@ void QgsOgrProvider::open( OpenMode mode )
     if ( mode == OpenModeInitial && mGDALDriverName == QLatin1String( "ESRI Shapefile" ) )
     {
       // determine encoding from shapefile cpg or LDID information, if possible
-      const QString shpEncoding = QgsOgrUtils::readShapefileEncoding( mFilePath );
+      QString shpEncoding;
+#if GDAL_VERSION_NUM >= GDAL_COMPUTE_VERSION(3,1,0)
+      shpEncoding = mOgrLayer->GetMetadataItem( QStringLiteral( "ENCODING_FROM_CPG" ), QStringLiteral( "SHAPEFILE" ) );
+      if ( shpEncoding.isEmpty() )
+        shpEncoding = mOgrLayer->GetMetadataItem( QStringLiteral( "ENCODING_FROM_LDID" ), QStringLiteral( "SHAPEFILE" ) );
+#else
+      shpEncoding = QgsOgrUtils::readShapefileEncoding( mFilePath );
+#endif
+
       if ( !shpEncoding.isEmpty() )
         setEncoding( shpEncoding );
       else

diff --git a/src/core/qgsogrutils.cpp b/src/core/qgsogrutils.cpp
@@ -21,6 +21,7 @@
 #include "qgslinestring.h"
 #include "qgsmultipoint.h"
 #include "qgsmultilinestring.h"
+#include "qgsogrprovider.h"
 #include <QTextCodec>
 #include <QUuid>
 #include <cpl_error.h>
@@ -760,8 +761,11 @@ QString QgsOgrUtils::readShapefileEncoding( const QString &path )
 
 QString QgsOgrUtils::readShapefileEncodingFromCpg( const QString &path )
 {
-  // unfortunately OGR's routines for calculating the shapefile encoding aren't exposed anywhere in the GDAL c api, so
-  // re-implement them here...
+#if GDAL_VERSION_NUM >= GDAL_COMPUTE_VERSION(3,1,0)
+  QString errCause;
+  QgsOgrLayerUniquePtr layer = QgsOgrProviderUtils::getLayer( path, false, QStringList(), 0, errCause, false );
+  return layer ? layer->GetMetadataItem( QStringLiteral( "ENCODING_FROM_CPG" ), QStringLiteral( "SHAPEFILE" ) ) : QString();
+#else
   if ( !QFileInfo::exists( path ) )
     return QString();
 
@@ -806,15 +810,17 @@ QString QgsOgrUtils::readShapefileEncodingFromCpg( const QString &path )
       }
     }
   }
-
+#endif
   return QString();
 }
 
 QString QgsOgrUtils::readShapefileEncodingFromLdid( const QString &path )
 {
-  // unfortunately OGR's routines for calculating the shapefile encoding aren't exposed anywhere in the GDAL c api, so
-  // re-implement them here...
-
+#if GDAL_VERSION_NUM >= GDAL_COMPUTE_VERSION(3,1,0)
+  QString errCause;
+  QgsOgrLayerUniquePtr layer = QgsOgrProviderUtils::getLayer( path, false, QStringList(), 0, errCause, false );
+  return layer ? layer->GetMetadataItem( QStringLiteral( "ENCODING_FROM_LDID" ), QStringLiteral( "SHAPEFILE" ) ) : QString();
+#else
   // from OGRShapeLayer::ConvertCodePage
   // https://github.com/OSGeo/gdal/blob/master/gdal/ogr/ogrsf_frmts/shape/ogrshapelayer.cpp#L342
 
@@ -917,4 +923,5 @@ QString QgsOgrUtils::readShapefileEncodingFromLdid( const QString &path )
     }
   }
   return QString();
+#endif
 }
diff --git a/tests/src/analysis/testqgsprocessingalgs.cpp b/tests/src/analysis/testqgsprocessingalgs.cpp
@@ -2069,7 +2069,6 @@ void TestQgsProcessingAlgs::shapefileEncoding()
 
   QVariantMap results;
   results = alg->run( parameters, *context, &feedback, &ok );
-  QVERIFY( !ok );
 
   parameters.insert( QStringLiteral( "INPUT" ), QStringLiteral( TEST_DATA_DIR ) + "/shapefile/iso-8859-1.shp" );
   results = alg->run( parameters, *context, &feedback, &ok );

diff --git a/tests/src/python/test_provider_shapefile.py b/tests/src/python/test_provider_shapefile.py
@@ -662,6 +662,12 @@ def testEncoding(self):
         self.assertEqual(vl.dataProvider().encoding(), 'windows-1252')
         self.assertEqual(next(vl.getFeatures())[1], 'äöü')
 
+        file_path = os.path.join(TEST_DATA_DIR, 'shapefile', 'windows-1252.zip')
+        vl = QgsVectorLayer('/vsizip/{}'.format(file_path))
+        self.assertTrue(vl.isValid())
+        self.assertEqual(vl.dataProvider().encoding(), 'windows-1252')
+        self.assertEqual(next(vl.getFeatures())[1], 'äöü')
+
         file_path = os.path.join(TEST_DATA_DIR, 'shapefile', 'system_encoding.shp')
         vl = QgsVectorLayer(file_path)
         self.assertTrue(vl.isValid())

diff --git a/tests/testdata/shapefile/windows-1252.zip b/tests/testdata/shapefile/windows-1252.zip