Port calculation of iterating destination to c++

Author: nyalldawson

python/core/processing/qgsprocessingutils.sip

@@ -126,6 +126,15 @@ class QgsProcessingUtils
  :rtype: QgsRectangle
 %End
 
+    static QVariant generateIteratingDestination( const QVariant &input, const QVariant &id, QgsProcessingContext &context );
+%Docstring
+ Converts an ``input`` parameter value for use in source iterating mode, where one individual sink
+ is created per input feature.
+ The ``id`` parameter represents the unique ID for this output, which is embedded into the resulting
+ parameter value.
+ :rtype: QVariant
+%End
+
 };
 
 

src/core/processing/qgsprocessingutils.cpp

@@ -23,6 +23,7 @@
 #include "qgsvectorlayerexporter.h"
 #include "qgsvectorfilewriter.h"
 #include "qgsmemoryproviderutils.h"
+#include "qgsprocessingparameters.h"
 
 QList<QgsRasterLayer *> QgsProcessingUtils::compatibleRasterLayers( QgsProject *project, bool sort )
 {
@@ -365,6 +366,40 @@ QgsRectangle QgsProcessingUtils::combineLayerExtents( const QList<QgsMapLayer *>
   return extent;
 }
 
+QVariant QgsProcessingUtils::generateIteratingDestination( const QVariant &input, const QVariant &id, QgsProcessingContext &context )
+{
+  if ( !input.isValid() )
+    return QStringLiteral( "memory:%1" ).arg( id.toString() );
+
+  if ( input.canConvert<QgsProcessingOutputLayerDefinition>() )
+  {
+    QgsProcessingOutputLayerDefinition fromVar = qvariant_cast<QgsProcessingOutputLayerDefinition>( input );
+    QVariant newSink = generateIteratingDestination( fromVar.sink, id, context );
+    fromVar.sink = QgsProperty::fromValue( newSink );
+    return fromVar;
+  }
+  else if ( input.canConvert<QgsProperty>() )
+  {
+    QString res = input.value< QgsProperty>().valueAsString( context.expressionContext() );
+    return generateIteratingDestination( res, id, context );
+  }
+  else
+  {
+    QString res = input.toString();
+    if ( res.startsWith( QStringLiteral( "memory:" ) ) )
+    {
+      return res + '_' + id.toString();
+    }
+    else
+    {
+      // assume a filename type output for now
+      // TODO - uris?
+      int lastIndex = res.lastIndexOf( '.' );
+      return res.left( lastIndex ) + '_' + id.toString() + res.mid( lastIndex );
+    }
+  }
+}
+
 
 //
 // QgsProcessingFeatureSource

src/core/processing/qgsprocessingutils.h

@@ -161,6 +161,14 @@ class CORE_EXPORT QgsProcessingUtils
      */
     static QgsRectangle combineLayerExtents( const QList< QgsMapLayer *> layers, const QgsCoordinateReferenceSystem &crs = QgsCoordinateReferenceSystem() );
 
+    /**
+     * Converts an \a input parameter value for use in source iterating mode, where one individual sink
+     * is created per input feature.
+     * The \a id parameter represents the unique ID for this output, which is embedded into the resulting
+     * parameter value.
+     */
+    static QVariant generateIteratingDestination( const QVariant &input, const QVariant &id, QgsProcessingContext &context );
+
   private:
 
     static bool canUseLayer( const QgsRasterLayer *layer );

tests/src/core/testqgsprocessing.cpp

@@ -290,6 +290,7 @@ class TestQgsProcessing: public QObject
     void processingFeatureSink();
     void algorithmScope();
     void validateInputCrs();
+    void generateIteratingDestination();
 
   private:
 
@@ -2714,5 +2715,32 @@ void TestQgsProcessing::validateInputCrs()
   alg.runValidateInputCrsChecks();
 }
 
+void TestQgsProcessing::generateIteratingDestination()
+{
+  QgsProcessingContext context;
+  QCOMPARE( QgsProcessingUtils::generateIteratingDestination( "memory:x", 1, context ).toString(), QStringLiteral( "memory:x_1" ) );
+  QCOMPARE( QgsProcessingUtils::generateIteratingDestination( "memory:x", 2, context ).toString(), QStringLiteral( "memory:x_2" ) );
+  QCOMPARE( QgsProcessingUtils::generateIteratingDestination( "ape.shp", 1, context ).toString(), QStringLiteral( "ape_1.shp" ) );
+  QCOMPARE( QgsProcessingUtils::generateIteratingDestination( "ape.shp", 2, context ).toString(), QStringLiteral( "ape_2.shp" ) );
+  QCOMPARE( QgsProcessingUtils::generateIteratingDestination( "/home/bif.o/ape.shp", 2, context ).toString(), QStringLiteral( "/home/bif.o/ape_2.shp" ) );
+
+  QgsProject p;
+  QgsProcessingOutputLayerDefinition def;
+  def.sink = QgsProperty::fromValue( "ape.shp" );
+  def.destinationProject = &p;
+  QVariant res = QgsProcessingUtils::generateIteratingDestination( def, 2, context );
+  QVERIFY( res.canConvert<QgsProcessingOutputLayerDefinition>() );
+  QgsProcessingOutputLayerDefinition fromVar = qvariant_cast<QgsProcessingOutputLayerDefinition>( res );
+  QCOMPARE( fromVar.sink.staticValue().toString(), QStringLiteral( "ape_2.shp" ) );
+  QCOMPARE( fromVar.destinationProject, &p );
+
+  def.sink = QgsProperty::fromExpression( "'ape' || '.shp'" );
+  res = QgsProcessingUtils::generateIteratingDestination( def, 2, context );
+  QVERIFY( res.canConvert<QgsProcessingOutputLayerDefinition>() );
+  fromVar = qvariant_cast<QgsProcessingOutputLayerDefinition>( res );
+  QCOMPARE( fromVar.sink.staticValue().toString(), QStringLiteral( "ape_2.shp" ) );
+  QCOMPARE( fromVar.destinationProject, &p );
+}
+
 QGSTEST_MAIN( TestQgsProcessing )
 #include "testqgsprocessing.moc"