Fixes #39137

qgis · Jan 14, 2021 · 6ea2ff5 · 6ea2ff5
1 parent 6daf9ef
commit 6ea2ff5
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Showing 4 changed files with 69 additions and 5 deletions.
diff --git a/python/gui/auto_generated/qgsexpressionlineedit.sip.in b/python/gui/auto_generated/qgsexpressionlineedit.sip.in
@@ -127,6 +127,15 @@ an expression context for the widget.
                   create an expression context when required.
 %End
 
+    void setExpressionContext( QgsExpressionContext &context );
+%Docstring
+Set a default expression context. Will be used if no QgsEcpressionContextGenerator or layer is set.
+
+:param context: The QgsExpressionContext to use.
+
+.. versionadded:: 3.18
+%End
+
   signals:
 
     void expressionChanged( const QString &expression );

diff --git a/src/gui/processing/qgsprocessingwidgetwrapperimpl.cpp b/src/gui/processing/qgsprocessingwidgetwrapperimpl.cpp
@@ -59,6 +59,8 @@
 #include "qgsrasterbandcombobox.h"
 #include "qgsprocessingoutputdestinationwidget.h"
 #include "qgscheckablecombobox.h"
+#include "qgsexpressioncontext.h"
+#include "qgsexpressioncontextutils.h"
 #include <QToolButton>
 #include <QLabel>
 #include <QHBoxLayout>
@@ -1839,12 +1841,15 @@ QgsProcessingAbstractParameterDefinitionWidget *QgsProcessingFileWidgetWrapper::
 QgsProcessingExpressionParameterDefinitionWidget::QgsProcessingExpressionParameterDefinitionWidget( QgsProcessingContext &context, const QgsProcessingParameterWidgetContext &widgetContext, const QgsProcessingParameterDefinition *definition, const QgsProcessingAlgorithm *algorithm, QWidget *parent )
   : QgsProcessingAbstractParameterDefinitionWidget( context, widgetContext, definition, algorithm, parent )
 {
+  mModel = widgetContext.model();
+
   QVBoxLayout *vlayout = new QVBoxLayout();
   vlayout->setContentsMargins( 0, 0, 0, 0 );
-
   vlayout->addWidget( new QLabel( tr( "Default value" ) ) );
 
   mDefaultLineEdit = new QgsExpressionLineEdit();
+  QgsExpressionContext expressionContext = createExpressionContext( context, algorithm );
+  mDefaultLineEdit->setExpressionContext( expressionContext );
   if ( const QgsProcessingParameterExpression *expParam = dynamic_cast<const QgsProcessingParameterExpression *>( definition ) )
     mDefaultLineEdit->setExpression( QgsProcessingParameters::parameterAsExpression( expParam, expParam->defaultValueForGui(), context ) );
   vlayout->addWidget( mDefaultLineEdit );
@@ -1858,21 +1863,22 @@ QgsProcessingExpressionParameterDefinitionWidget::QgsProcessingExpressionParamet
   if ( const QgsProcessingParameterExpression *expParam = dynamic_cast<const QgsProcessingParameterExpression *>( definition ) )
     initialParent = expParam->parentLayerParameterName();
 
-  if ( auto *lModel = widgetContext.model() )
+
+  if ( mModel )
   {
     // populate combo box with other model input choices
-    const QMap<QString, QgsProcessingModelParameter> components = lModel->parameterComponents();
+    const QMap<QString, QgsProcessingModelParameter> components = mModel->parameterComponents();
     for ( auto it = components.constBegin(); it != components.constEnd(); ++it )
     {
-      if ( const QgsProcessingParameterFeatureSource *definition = dynamic_cast< const QgsProcessingParameterFeatureSource * >( lModel->parameterDefinition( it.value().parameterName() ) ) )
+      if ( const QgsProcessingParameterFeatureSource *definition = dynamic_cast< const QgsProcessingParameterFeatureSource * >( mModel->parameterDefinition( it.value().parameterName() ) ) )
       {
         mParentLayerComboBox-> addItem( definition->description(), definition->name() );
         if ( !initialParent.isEmpty() && initialParent == definition->name() )
         {
           mParentLayerComboBox->setCurrentIndex( mParentLayerComboBox->count() - 1 );
         }
       }
-      else if ( const QgsProcessingParameterVectorLayer *definition = dynamic_cast< const QgsProcessingParameterVectorLayer * >( lModel->parameterDefinition( it.value().parameterName() ) ) )
+      else if ( const QgsProcessingParameterVectorLayer *definition = dynamic_cast< const QgsProcessingParameterVectorLayer * >( mModel->parameterDefinition( it.value().parameterName() ) ) )
       {
         mParentLayerComboBox-> addItem( definition->description(), definition->name() );
         if ( !initialParent.isEmpty() && initialParent == definition->name() )
@@ -1898,9 +1904,46 @@ QgsProcessingParameterDefinition *QgsProcessingExpressionParameterDefinitionWidg
 {
   auto param = qgis::make_unique< QgsProcessingParameterExpression >( name, description, mDefaultLineEdit->expression(), mParentLayerComboBox->currentData().toString() );
   param->setFlags( flags );
+  if ( mModel )
+  {
+    QStringList extraVars = mModel->variables().keys();
+    param->setAdditionalExpressionContextVariables( extraVars );
+  }
   return param.release();
 }
 
+QgsExpressionContext QgsProcessingExpressionParameterDefinitionWidget::createExpressionContext( QgsProcessingContext &context, const QgsProcessingAlgorithm *algorithm ) const
+{
+  QgsExpressionContext finalContext = context.expressionContext();
+  QString childId;
+
+  QgsExpressionContextScope *algScope = QgsExpressionContextUtils::processingAlgorithmScope( algorithm, QVariantMap(), context );
+  finalContext.appendScope( algScope );
+
+  QgsExpressionContextScope *modelScope = QgsExpressionContextUtils::processingModelAlgorithmScope( mModel, QVariantMap(), context );
+  finalContext << modelScope;
+  const QgsProcessingAlgorithm *childAlg = nullptr;
+  if ( mModel->childAlgorithms().contains( childId ) )
+    childAlg = mModel->childAlgorithm( childId ).algorithm();
+  QgsExpressionContextScope *algorithmScope = QgsExpressionContextUtils::processingAlgorithmScope( childAlg, QVariantMap(), context );
+  finalContext << algorithmScope;
+
+  QgsExpressionContextScope *childScope = mModel->createExpressionContextScopeForChildAlgorithm( childId, context, QVariantMap(), QVariantMap() );
+  finalContext << childScope;
+
+  QStringList highlightedVariables = childScope->variableNames();
+  QStringList highlightedFunctions = childScope->functionNames();
+  highlightedVariables += algorithmScope->variableNames();
+  highlightedVariables += algScope->variableNames();
+  highlightedVariables += mModel->variables().keys();
+  highlightedFunctions += algScope->functionNames();
+  highlightedFunctions += algorithmScope->functionNames();
+  finalContext.setHighlightedVariables( highlightedVariables );
+  finalContext.setHighlightedFunctions( highlightedFunctions );
+
+  return finalContext;
+}
+
 QgsProcessingExpressionWidgetWrapper::QgsProcessingExpressionWidgetWrapper( const QgsProcessingParameterDefinition *parameter, QgsProcessingGui::WidgetType type, QWidget *parent )
   : QgsAbstractProcessingParameterWidgetWrapper( parameter, type, parent )
 {

diff --git a/src/gui/processing/qgsprocessingwidgetwrapperimpl.h b/src/gui/processing/qgsprocessingwidgetwrapperimpl.h
@@ -66,6 +66,8 @@ class QgsProcessingMapLayerComboBox;
 class QgsRasterBandComboBox;
 class QgsProcessingLayerOutputDestinationWidget;
 class QgsCheckableComboBox;
+class QgsProcessingModelAlgorithm;
+class QgsExpressionContext;
 
 ///@cond PRIVATE
 
@@ -633,11 +635,13 @@ class GUI_EXPORT QgsProcessingExpressionParameterDefinitionWidget : public QgsPr
         const QgsProcessingParameterDefinition *definition = nullptr,
         const QgsProcessingAlgorithm *algorithm = nullptr, QWidget *parent SIP_TRANSFERTHIS = nullptr );
     QgsProcessingParameterDefinition *createParameter( const QString &name, const QString &description, QgsProcessingParameterDefinition::Flags flags ) const override;
+    QgsExpressionContext createExpressionContext( QgsProcessingContext &context, const QgsProcessingAlgorithm *algorithm ) const;
 
   private:
 
     QComboBox *mParentLayerComboBox = nullptr;
     QgsExpressionLineEdit *mDefaultLineEdit = nullptr;
+    QgsProcessingModelAlgorithm *mModel = nullptr;
 
 };
 
@@ -662,6 +666,7 @@ class GUI_EXPORT QgsProcessingExpressionWidgetWrapper : public QgsAbstractProces
     // QgsProcessingParameterWidgetWrapper interface
     QWidget *createWidget() override SIP_FACTORY;
     void postInitialize( const QList< QgsAbstractProcessingParameterWidgetWrapper * > &wrappers ) override;
+
   public slots:
     void setParentLayerWrapperValue( const QgsAbstractProcessingParameterWidgetWrapper *parentWrapper );
   protected:

diff --git a/src/gui/qgsexpressionlineedit.h b/src/gui/qgsexpressionlineedit.h
@@ -132,6 +132,13 @@ class GUI_EXPORT QgsExpressionLineEdit : public QWidget
      */
     void registerExpressionContextGenerator( const QgsExpressionContextGenerator *generator );
 
+    /**
+     * Set a default expression context. Will be used if no QgsEcpressionContextGenerator or layer is set.
+     * \param context The QgsExpressionContext to use.
+     * \since QGIS 3.18
+     */
+    void setExpressionContext( QgsExpressionContext &context ) { mExpressionContext = context; }
+
   signals:
 
     /**