Implement a QgsProviderRegistry decodeUri function + test

python/core/auto_generated/qgsproviderregistry.sip.in

@@ -78,7 +78,7 @@ Sets library directory where to search for plugins
 %Docstring
 Creates a new instance of a provider.
 
-:param providerKey: identificator of the provider
+:param providerKey: identifier of the provider
 :param dataSource: string containing data source for the provider
 :param options: provider options
 
@@ -89,9 +89,25 @@ Creates a new instance of a provider.
 %Docstring
 Returns the provider capabilities
 
-:param providerKey: identificator of the provider
+:param providerKey: identifier of the provider
 
 .. versionadded:: 2.6
+%End
+
+    QVariantMap decodeUri( const QString &providerKey, const QString &uri );
+%Docstring
+Returns the components (e.g. file path, layer name) of a provider uri
+
+:param providerKey: identifier of the provider
+:param uri: uri string
+
+:return: map containing components
+
+.. note::
+
+   this function may not be supported by all providers, an empty map will be returned in such case
+
+.. versionadded:: 3.4
 %End
 
     QWidget *createSelectionWidget( const QString &providerKey,
@@ -109,7 +125,7 @@ responsible for deleting the returned widget.
 %Docstring
 Gets pointer to provider function
 
-:param providerKey: identificator of the provider
+:param providerKey: identifier of the provider
 :param functionName: name of function
 
 :return: pointer to function or NULL on error. If the provider uses direct provider

src/core/qgsproviderregistry.cpp

@@ -43,6 +43,8 @@ typedef QString databaseDrivers_t();
 typedef QString directoryDrivers_t();
 typedef QString protocolDrivers_t();
 typedef void initProviderFunction_t();
+typedef QVariantMap decodeUri_t( const QString &uri );
+
 //typedef int dataCapabilities_t();
 //typedef QgsDataItem * dataItem_t(QString);
 
@@ -438,6 +440,22 @@ QgsDataProvider *QgsProviderRegistry::createProvider( QString const &providerKey
   return dataProvider;
 } // QgsProviderRegistry::setDataProvider
 
+QVariantMap QgsProviderRegistry::decodeUri( const QString &providerKey, const QString &uri )
+{
+  std::unique_ptr< QLibrary > library( createProviderLibrary( providerKey ) );
+  if ( !library )
+  {
+    return QVariantMap();
+  }
+
+  decodeUri_t *decodeUri = reinterpret_cast< decodeUri_t *>( cast_to_fptr( library->resolve( "decodeUri" ) ) );
+  if ( !decodeUri )
+  {
+    return QVariantMap();
+  }
+  return decodeUri( uri );
+}
+
 int QgsProviderRegistry::providerCapabilities( const QString &providerKey ) const
 {
   std::unique_ptr< QLibrary > library( createProviderLibrary( providerKey ) );

src/core/qgsproviderregistry.h

@@ -91,7 +91,7 @@ class CORE_EXPORT QgsProviderRegistry
 
     /**
      * Creates a new instance of a provider.
-     * \param providerKey identificator of the provider
+     * \param providerKey identifier of the provider
      * \param dataSource  string containing data source for the provider
      * \param options provider options
      * \returns new instance of provider or NULL on error
@@ -102,11 +102,21 @@ class CORE_EXPORT QgsProviderRegistry
 
     /**
      * Returns the provider capabilities
-        \param providerKey identificator of the provider
+        \param providerKey identifier of the provider
         \since QGIS 2.6
      */
     int providerCapabilities( const QString &providerKey ) const;
 
+    /**
+     * Returns the components (e.g. file path, layer name) of a provider uri
+        \param providerKey identifier of the provider
+        \param uri uri string
+        \returns map containing components
+        \note this function may not be supported by all providers, an empty map will be returned in such case
+        \since QGIS 3.4
+     */
+    QVariantMap decodeUri( const QString &providerKey, const QString &uri );
+
     /**
      * Returns a new widget for selecting layers from a provider.
      * Either the \a parent widget must be set or the caller becomes
@@ -119,7 +129,7 @@ class CORE_EXPORT QgsProviderRegistry
 
     /**
      * Gets pointer to provider function
-     * \param providerKey identificator of the provider
+     * \param providerKey identifier of the provider
      * \param functionName name of function
      * \returns pointer to function or NULL on error. If the provider uses direct provider
      * function pointers instead of a library nullptr will be returned.

src/providers/gdal/qgsgdalprovider.cpp

@@ -1974,6 +1974,30 @@ QStringList QgsGdalProvider::subLayers() const
   return mSubLayers;
 }
 
+
+QGISEXTERN QVariantMap decodeUri( const QString &uri )
+{
+  QString path = uri;
+  QString layerName;
+
+  QString vsiPrefix = qgsVsiPrefix( path );
+  if ( !path.isEmpty() )
+    path = path.mid( vsiPrefix.count() );
+
+  if ( path.indexOf( ':' ) != -1 )
+  {
+    QStringList parts = path.split( ':' );
+    path  = parts[1];
+    if ( parts.count() > 2 )
+      layerName = parts[2];
+  }
+
+  QVariantMap uriComponents;
+  uriComponents.insert( QStringLiteral( "path" ), path );
+  uriComponents.insert( QStringLiteral( "layerName" ), layerName );
+  return uriComponents;
+}
+
 /**
  * Class factory to return a pointer to a newly created
  * QgsGdalProvider object

src/providers/ogr/qgsogrprovider.cpp

@@ -3021,6 +3021,39 @@ QString createFilters( const QString &type )
   }
 }
 
+QGISEXTERN QVariantMap decodeUri( const QString &uri )
+{
+  QString path = uri;
+  QString layerName;
+  int layerId = -1;
+
+  int pipeIndex = path.indexOf( '|' );
+  if ( pipeIndex != -1 )
+  {
+    if ( path.indexOf( QLatin1String( "|layername=" ) ) != -1 )
+    {
+      QRegularExpression regex( QStringLiteral( "\\|layername=([^|]*)" ) );
+      layerName = regex.match( path ).captured( 1 );
+    }
+    else if ( path.indexOf( QLatin1String( "|layerid=" ) ) )
+    {
+      QRegularExpression regex( QStringLiteral( "\\|layerid=([^|]*)" ) );
+      layerId = regex.match( path ).captured( 1 ).toInt();
+    }
+
+    path = path.left( pipeIndex );
+  }
+
+  QString vsiPrefix = qgsVsiPrefix( path );
+  if ( !vsiPrefix.isEmpty() )
+    path = path.mid( vsiPrefix.count() );
+
+  QVariantMap uriComponents;
+  uriComponents.insert( QStringLiteral( "path" ), path );
+  uriComponents.insert( QStringLiteral( "layerName" ), layerName );
+  uriComponents.insert( QStringLiteral( "layerId" ), layerId > -1 ? layerId : QVariant() ) ;
+  return uriComponents;
+}
 
 QGISEXTERN QString fileVectorFilters()
 {

src/providers/ogr/qgsogrprovider.h

@@ -96,7 +96,6 @@ class QgsOgrProvider : public QgsVectorDataProvider
      */
     QString dataSourceUri( bool expandAuthConfig = false ) const override;
 
-
     QgsAbstractFeatureSource *featureSource() const override;
 
     QgsCoordinateReferenceSystem crs() const override;

tests/src/providers/testqgsgdalprovider.cpp

@@ -44,6 +44,7 @@ class TestQgsGdalProvider : public QObject
     void init() {}// will be called before each testfunction is executed.
     void cleanup() {}// will be called after every testfunction.
 
+    void decodeUri(); // test decode URI implementation
     void scaleDataType(); //test resultant data types for int raster with float scale (#11573)
     void warpedVrt(); //test loading raster which requires a warped vrt
     void noData();
@@ -82,6 +83,20 @@ void TestQgsGdalProvider::cleanupTestCase()
   }
 }
 
+void TestQgsGdalProvider::decodeUri()
+{
+  QString uri = QStringLiteral( "/home/to/path/raster.tif" );
+  QVariantMap components;
+
+  components = QgsProviderRegistry::instance()->decodeUri( QStringLiteral( "gdal" ), uri );
+  QCOMPARE( components[QStringLiteral( "path" )].toString(), uri );
+
+  uri = QStringLiteral( "gpkg:/home/to/path/my_file.gpkg:layer_name" );
+  components = QgsProviderRegistry::instance()->decodeUri( QStringLiteral( "gdal" ), uri );
+  QCOMPARE( components[QStringLiteral( "path" )].toString(), QStringLiteral( "/home/to/path/my_file.gpkg" ) );
+  QCOMPARE( components[QStringLiteral( "layerName" )].toString(), QStringLiteral( "layer_name" ) );
+}
+
 void TestQgsGdalProvider::scaleDataType()
 {
   QString rasterWithOffset = QStringLiteral( TEST_DATA_DIR ) + "/int_raster_with_scale.tif";

tests/src/python/test_provider_ogr_gpkg.py

@@ -28,6 +28,7 @@ from qgis.core import (QgsFeature,
                        QgsField,
                        QgsFieldConstraints,
                        QgsGeometry,
+                       QgsProviderRegistry,
                        QgsRectangle,
                        QgsSettings,
                        QgsVectorLayer,
@@ -95,6 +96,25 @@ class TestPyQgsOGRProviderGpkg(unittest.TestCase):
 
         QgsSettings().clear()
 
+    def testDecodeUri(self):
+
+        filename = '/home/to/path/my_file.gpkg'
+
+        registry = QgsProviderRegistry.instance()
+        uri = filename
+        components = registry.decodeUri('ogr', uri)
+        self.assertEqual(components["path"], filename)
+
+        uri = '{}|layername=test'.format(filename)
+        components = registry.decodeUri('ogr', uri)
+        self.assertEqual(components["path"], filename)
+        self.assertEqual(components["layerName"], 'test')
+
+        uri = '{}|layerid=0'.format(filename)
+        components = registry.decodeUri('ogr', uri)
+        self.assertEqual(components["path"], filename)
+        self.assertEqual(components["layerId"], 0)
+
     def testSingleToMultiPolygonPromotion(self):
 
         tmpfile = os.path.join(self.basetestpath, 'testSingleToMultiPolygonPromotion.gpkg')