Explicitly pass QgsProject object when dealing with expression contexts

Continued effort to reduce number of uses of QgsProject as singleton...

doc/api_break.dox

@@ -887,6 +887,12 @@ QgsExpression::Function       {#qgis_api_break_3_0_QgsExpression_Function}
 - `QgsExpression::Function::helptext()` has been renamed to `helpText()`
 
 
+QgsExpressionContextUtils       {#qgis_api_break_3_0_QgsExpressionContextUtils}
+-------------------------
+
+- projectScope(), setProjectVariable() and setProjectVariables() require pointer to QgsProject as the first argument.
+
+
 QgsFeature        {#qgis_api_break_3_0_QgsFeature}
 ----------
 

python/core/qgsexpressioncontext.sip

@@ -217,6 +217,12 @@ class QgsExpressionContext
 
     QgsExpressionContext();
 
+    /** Initializes the context with given list of scopes.
+     * Ownership of the scopes is transferred to the stack.
+     * @note added in QGIS 3.0
+     */
+    explicit QgsExpressionContext( const QList<QgsExpressionContextScope*>& scopes /Transfer/ );
+
     /** Copy constructor
      */
     QgsExpressionContext( const QgsExpressionContext& other );
@@ -359,6 +365,14 @@ class QgsExpressionContext
      */
     void appendScope( QgsExpressionContextScope* scope /Transfer/ );
 
+    /** Appends a list of scopes to the end of the context. This scopes will override
+     * any matching variables or functions provided by existing scopes within the
+     * context. Ownership of the scopes is transferred to the stack.
+     * @param scopes scopes to append to context
+     * @note added in QGIS 3.0
+     */
+    void appendScopes( const QList<QgsExpressionContextScope*>& scopes /Transfer/ );
+
     /**
      * Removes the last scope from the expression context and return it.
      */
@@ -484,15 +498,20 @@ class QgsExpressionContextUtils
     static QgsExpressionContextScope* globalScope() /Factory/;
     static void setGlobalVariable( const QString& name, const QVariant& value );
     static void setGlobalVariables( const QVariantMap& variables );
-    static QgsExpressionContextScope* projectScope() /Factory/;
-    static void setProjectVariable( const QString& name, const QVariant& value );
-    static void setProjectVariables( const QVariantMap& variables );
+    static QgsExpressionContextScope* projectScope( const QgsProject* project ) /Factory/;
+    static void setProjectVariable( QgsProject* project, const QString& name, const QVariant& value );
+    static void setProjectVariables( QgsProject* project, const QVariantMap& variables );
 
     /** Creates a new scope which contains variables and functions relating to a QgsMapLayer.
      * For instance, layer name, id and fields.
      */
     static QgsExpressionContextScope* layerScope( const QgsMapLayer *layer ) /Factory/;
 
+    /** Creates a list of three scopes: global, layer's project and layer.
+     * @note added in QGIS 3.0
+     */
+    static QList<QgsExpressionContextScope*> globalProjectLayerScopes( const QgsMapLayer* layer ) /Factory/;
+
     /** Sets a layer context variable. This variable will be contained within scopes retrieved via
      * layerScope().
      * @param layer map layer

python/gui/symbology-ng/qgssymbolwidgetcontext.sip

@@ -57,5 +57,11 @@
      * @see setAdditionalExpressionContextScopes()
      */
     QList< QgsExpressionContextScope > additionalExpressionContextScopes() const;
+
+    /** Returns list of scopes: global, project, atlas, map, layer.
+     * Ownership is transferred to the caller.
+     * @note added in QGIS 3.0
+     */
+    QList<QgsExpressionContextScope*> globalProjectAtlasMapLayerScopes( const QgsMapLayer* layer ) const /Factory/;
 };
 

src/app/composer/qgscompositionwidget.cpp

@@ -205,7 +205,7 @@ void QgsCompositionWidget::updateVariables()
 {
   QgsExpressionContext context;
   context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::compositionScope( mComposition );
   mVariableEditor->setContext( &context );
   mVariableEditor->setEditableScopeIndex( 2 );

src/app/qgsattributetabledialog.cpp

@@ -54,7 +54,7 @@ QgsExpressionContext QgsAttributeTableDialog::createExpressionContext() const
 {
   QgsExpressionContext expContext;
   expContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope();
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() );
 
   if ( mLayer )
     expContext << QgsExpressionContextUtils::layerScope( mLayer );
@@ -474,10 +474,7 @@ void QgsAttributeTableDialog::runFieldCalculation( QgsVectorLayer* layer, const
 
   int rownum = 1;
 
-  QgsExpressionContext context;
-  context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::layerScope( layer );
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( layer ) );
 
   QgsField fld = layer->fields().at( fieldindex );
 
@@ -583,10 +580,7 @@ void QgsAttributeTableDialog::filterColumnChanged( QObject* filterAction )
 void QgsAttributeTableDialog::filterExpressionBuilder()
 {
   // Show expression builder
-  QgsExpressionContext context;
-  context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::layerScope( mLayer );
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
 
   QgsExpressionBuilderDialog dlg( mLayer, mFilterQuery->text(), this, QStringLiteral( "generic" ), context );
   dlg.setWindowTitle( tr( "Expression based filter" ) );
@@ -965,10 +959,7 @@ void QgsAttributeTableDialog::setFilterExpression( const QString& filterString,
     return;
   }
 
-  QgsExpressionContext context;
-  context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::layerScope( mLayer );
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
 
   if ( !filterExpression.prepare( &context ) )
   {

src/app/qgsdiagramproperties.cpp

@@ -47,7 +47,7 @@ QgsExpressionContext QgsDiagramProperties::createExpressionContext() const
 {
   QgsExpressionContext expContext;
   expContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::atlasScope( nullptr )
   << QgsExpressionContextUtils::mapSettingsScope( mMapCanvas->mapSettings() )
   << QgsExpressionContextUtils::layerScope( mLayer );
@@ -571,7 +571,7 @@ void QgsDiagramProperties::on_mFindMaximumValueButton_clicked()
     QgsExpression exp( sizeFieldNameOrExp );
     QgsExpressionContext context;
     context << QgsExpressionContextUtils::globalScope()
-    << QgsExpressionContextUtils::projectScope()
+    << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
     << QgsExpressionContextUtils::mapSettingsScope( mMapCanvas->mapSettings() )
     << QgsExpressionContextUtils::layerScope( mLayer );
 
@@ -859,7 +859,7 @@ QString QgsDiagramProperties::showExpressionBuilder( const QString& initialExpre
 {
   QgsExpressionContext context;
   context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::atlasScope( nullptr )
   << QgsExpressionContextUtils::mapSettingsScope( mMapCanvas->mapSettings() )
   << QgsExpressionContextUtils::layerScope( mLayer );

src/app/qgsfieldcalculator.cpp

@@ -39,10 +39,7 @@ QgsFieldCalculator::QgsFieldCalculator( QgsVectorLayer* vl, QWidget* parent )
     return;
 
 
-  QgsExpressionContext expContext;
-  expContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::layerScope( mVectorLayer );
+  QgsExpressionContext expContext( QgsExpressionContextUtils::globalProjectLayerScopes( mVectorLayer ) );
 
   expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "row_number" ), 1, true ) );
   expContext.setHighlightedVariables( QStringList() << QStringLiteral( "row_number" ) );
@@ -168,10 +165,7 @@ void QgsFieldCalculator::accept()
   exp.setDistanceUnits( QgsProject::instance()->distanceUnits() );
   exp.setAreaUnits( QgsProject::instance()->areaUnits() );
 
-  QgsExpressionContext expContext;
-  expContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::layerScope( mVectorLayer );
+  QgsExpressionContext expContext( QgsExpressionContextUtils::globalProjectLayerScopes( mVectorLayer ) );
 
   if ( !exp.prepare( &expContext ) )
   {

src/app/qgsfieldsproperties.cpp

@@ -841,7 +841,7 @@ void QgsFieldsProperties::updateExpression()
 
   QgsExpressionContext context;
   context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope();
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() );
 
   QgsExpressionBuilderDialog dlg( mLayer, exp, nullptr, QStringLiteral( "generic" ), context );
 

src/app/qgsidentifyresultsdialog.cpp

@@ -587,10 +587,7 @@ void QgsIdentifyResultsDialog::addFeature( QgsVectorLayer *vlayer, const QgsFeat
   if ( !featureLabeled )
   {
     featItem->setText( 0, tr( "Title" ) );
-    QgsExpressionContext context;
-    context << QgsExpressionContextUtils::globalScope()
-    << QgsExpressionContextUtils::projectScope()
-    << QgsExpressionContextUtils::layerScope( vlayer );
+    QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( vlayer ) );
     context.setFeature( f );
 
     QString value = QgsExpression( vlayer->displayExpression() ).evaluate( &context ).toString();

src/app/qgslabelinggui.cpp

@@ -26,7 +26,7 @@ QgsExpressionContext QgsLabelingGui::createExpressionContext() const
 {
   QgsExpressionContext expContext;
   expContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::atlasScope( nullptr )
   << QgsExpressionContextUtils::mapSettingsScope( QgisApp::instance()->mapCanvas()->mapSettings() );
 

src/app/qgslabelpropertydialog.cpp

@@ -223,7 +223,7 @@ void QgsLabelPropertyDialog::setDataDefinedValues( const QgsPalLayerSettings &la
 
   QgsExpressionContext context;
   context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::atlasScope( nullptr )
   << QgsExpressionContextUtils::mapSettingsScope( QgisApp::instance()->mapCanvas()->mapSettings() )
   << QgsExpressionContextUtils::layerScope( vlayer );

src/app/qgsmaptoolfeatureaction.cpp

@@ -134,7 +134,7 @@ bool QgsMapToolFeatureAction::doAction( QgsVectorLayer *layer, int x, int y )
       // define custom substitutions: layer id and clicked coords
       QgsExpressionContext context;
       context << QgsExpressionContextUtils::globalScope()
-      << QgsExpressionContextUtils::projectScope()
+      << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
       << QgsExpressionContextUtils::mapSettingsScope( mCanvas->mapSettings() );
       QgsExpressionContextScope* actionScope = new QgsExpressionContextScope();
       actionScope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "click_x" ), point.x(), true ) );

src/app/qgspointmarkeritem.cpp

@@ -17,6 +17,7 @@
 #include "qgssymbol.h"
 #include "qgsmapcanvas.h"
 #include "qgsmapsettings.h"
+#include "qgsproject.h"
 #include <QPainter>
 #include <cmath>
 
@@ -31,7 +32,7 @@ QgsRenderContext QgsPointMarkerItem::renderContext( QPainter* painter )
 {
   QgsExpressionContext context;
   context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::atlasScope( nullptr );
   if ( mMapCanvas )
   {

src/app/qgsprojectproperties.cpp

@@ -723,7 +723,7 @@ QgsProjectProperties::QgsProjectProperties( QgsMapCanvas* mapCanvas, QWidget *pa
 
   // Variables editor
   mVariableEditor->context()->appendScope( QgsExpressionContextUtils::globalScope() );
-  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::projectScope() );
+  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::projectScope( QgsProject::instance() ) );
   mVariableEditor->reloadContext();
   mVariableEditor->setEditableScopeIndex( 1 );
 

src/app/qgsrulebasedlabelingwidget.cpp

@@ -19,6 +19,7 @@
 #include "qgsfeatureiterator.h"
 #include "qgslabelinggui.h"
 #include "qgsmapcanvas.h"
+#include "qgsproject.h"
 #include "qgsrulebasedlabeling.h"
 #include "qgsvectorlayer.h"
 #include "qgsvectorlayerlabeling.h"
@@ -27,6 +28,27 @@
 #include <QClipboard>
 #include <QMessageBox>
 
+
+static QList<QgsExpressionContextScope*> _globalProjectAtlasMapLayerScopes( QgsMapCanvas* mapCanvas, const QgsMapLayer* layer )
+{
+  QList<QgsExpressionContextScope*> scopes;
+  scopes << QgsExpressionContextUtils::globalScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
+  << QgsExpressionContextUtils::atlasScope( nullptr );
+  if ( mapCanvas )
+  {
+    scopes << QgsExpressionContextUtils::mapSettingsScope( mapCanvas->mapSettings() )
+    << new QgsExpressionContextScope( mapCanvas->expressionContextScope() );
+  }
+  else
+  {
+    scopes << QgsExpressionContextUtils::mapSettingsScope( QgsMapSettings() );
+  }
+  scopes << QgsExpressionContextUtils::layerScope( layer );
+  return scopes;
+}
+
+
 QgsRuleBasedLabelingWidget::QgsRuleBasedLabelingWidget( QgsVectorLayer* layer, QgsMapCanvas* canvas, QWidget* parent )
     : QgsPanelWidget( parent )
     , mLayer( layer )
@@ -643,20 +665,7 @@ void QgsLabelingRulePropsWidget::testFilter()
     return;
   }
 
-  QgsExpressionContext context;
-  context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::atlasScope( nullptr );
-  if ( mMapCanvas )
-  {
-    context << QgsExpressionContextUtils::mapSettingsScope( mMapCanvas->mapSettings() )
-    << new QgsExpressionContextScope( mMapCanvas->expressionContextScope() );
-  }
-  else
-  {
-    context << QgsExpressionContextUtils::mapSettingsScope( QgsMapSettings() );
-  }
-  context << QgsExpressionContextUtils::layerScope( mLayer );
+  QgsExpressionContext context( _globalProjectAtlasMapLayerScopes( mMapCanvas, mLayer ) );
 
   if ( !filter.prepare( &context ) )
   {
@@ -686,22 +695,10 @@ void QgsLabelingRulePropsWidget::testFilter()
   QMessageBox::information( this, tr( "Filter" ), tr( "Filter returned %n feature(s)", "number of filtered features", count ) );
 }
 
+
 void QgsLabelingRulePropsWidget::buildExpression()
 {
-  QgsExpressionContext context;
-  context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::atlasScope( nullptr );
-  if ( mMapCanvas )
-  {
-    context << QgsExpressionContextUtils::mapSettingsScope( mMapCanvas->mapSettings() )
-    << new QgsExpressionContextScope( mMapCanvas->expressionContextScope() );
-  }
-  else
-  {
-    context << QgsExpressionContextUtils::mapSettingsScope( QgsMapSettings() );
-  }
-  context << QgsExpressionContextUtils::layerScope( mLayer );
+  QgsExpressionContext context( _globalProjectAtlasMapLayerScopes( mMapCanvas, mLayer ) );
 
   QgsExpressionBuilderDialog dlg( mLayer, editFilter->text(), this, QStringLiteral( "generic" ), context );
 

src/app/qgsselectbyformdialog.cpp

@@ -68,10 +68,7 @@ void QgsSelectByFormDialog::zoomToFeatures( const QString& filter )
 {
   QgsFeatureIds ids;
 
-  QgsExpressionContext context;
-  context << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
-  << QgsExpressionContextUtils::layerScope( mLayer );
+  QgsExpressionContext context( QgsExpressionContextUtils::globalProjectLayerScopes( mLayer ) );
 
   QgsFeatureRequest request = QgsFeatureRequest().setFilterExpression( filter )
                               .setExpressionContext( context )

src/app/qgsstatisticalsummarydockwidget.cpp

@@ -62,7 +62,7 @@ QgsExpressionContext QgsStatisticalSummaryDockWidget::createExpressionContext()
 {
   QgsExpressionContext expContext;
   expContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::mapSettingsScope( QgisApp::instance()->mapCanvas()->mapSettings() )
   << QgsExpressionContextUtils::layerScope( mLayer );
 

src/app/qgsvectorlayerproperties.cpp

@@ -112,7 +112,7 @@ QgsVectorLayerProperties::QgsVectorLayerProperties(
   connect( mOptionsStackedWidget, SIGNAL( currentChanged( int ) ), this, SLOT( mOptionsStackedWidget_CurrentChanged( int ) ) );
 
   mContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope()
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
   << QgsExpressionContextUtils::atlasScope( nullptr )
   << QgsExpressionContextUtils::mapSettingsScope( QgisApp::instance()->mapCanvas()->mapSettings() )
   << QgsExpressionContextUtils::layerScope( mLayer );
@@ -1333,7 +1333,7 @@ void QgsVectorLayerProperties::updateVariableEditor()
   QgsExpressionContext context;
   mVariableEditor->setContext( &context );
   mVariableEditor->context()->appendScope( QgsExpressionContextUtils::globalScope() );
-  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::projectScope() );
+  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::projectScope( QgsProject::instance() ) );
   mVariableEditor->context()->appendScope( QgsExpressionContextUtils::layerScope( mLayer ) );
   mVariableEditor->reloadContext();
   mVariableEditor->setEditableScopeIndex( 2 );

src/core/composer/qgsatlascomposition.cpp

@@ -718,7 +718,7 @@ QgsExpressionContext QgsAtlasComposition::createExpressionContext()
 {
   QgsExpressionContext expressionContext;
   expressionContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope();
+  << QgsExpressionContextUtils::projectScope( QgsProject::instance() );
   if ( mComposition )
     expressionContext << QgsExpressionContextUtils::compositionScope( mComposition );