Allow vector rendering cancelation to also cancel feature iteration for that request

nyalldawson · nyalldawson · commit 6fa3bf8e8b1a · 2019-02-01T21:08:56.000+11:00
Connect the cancel rendering signal to the iteration cancelation.
This allows providers (e.g. WFS, AFS) to abort slow network requests
when they have been triggered by a render request and that request
is no longer required.

Allows much faster quit, render cancelation when using WFS/AFS layers.
diff --git a/src/core/qgsvectorlayerrenderer.cpp b/src/core/qgsvectorlayerrenderer.cpp
@@ -42,7 +42,7 @@
 QgsVectorLayerRenderer::QgsVectorLayerRenderer( QgsVectorLayer *layer, QgsRenderContext &context )
   : QgsMapLayerRenderer( layer->id() )
   , mContext( context )
-  , mInterruptionChecker( context )
+  , mInterruptionChecker( qgis::make_unique< QgsVectorLayerRendererInterruptionChecker >( context ) )
   , mLayer( layer )
   , mFields( layer->fields() )
   , mLabeling( false )
@@ -106,6 +106,10 @@ QgsVectorLayerRenderer::~QgsVectorLayerRenderer()
   delete mSource;
 }
 
+QgsFeedback *QgsVectorLayerRenderer::feedback() const
+{
+  return mInterruptionChecker.get();
+}
 
 bool QgsVectorLayerRenderer::render()
 {
@@ -239,7 +243,7 @@ bool QgsVectorLayerRenderer::render()
   // slow fetchFeature() implementations, such as in the WFS provider, can
   // check it, instead of relying on just the mContext.renderingStopped() check
   // in drawRenderer()
-  fit.setInterruptionChecker( &mInterruptionChecker );
+  fit.setInterruptionChecker( mInterruptionChecker.get() );
 
   if ( ( mRenderer->capabilities() & QgsFeatureRenderer::SymbolLevels ) && mRenderer->usingSymbolLevels() )
     drawRendererLevels( fit );
diff --git a/src/core/qgsvectorlayerrenderer.h b/src/core/qgsvectorlayerrenderer.h
@@ -76,6 +76,7 @@ class QgsVectorLayerRenderer : public QgsMapLayerRenderer
   public:
     QgsVectorLayerRenderer( QgsVectorLayer *layer, QgsRenderContext &context );
     ~QgsVectorLayerRenderer() override;
+    QgsFeedback *feedback() const override;
 
     bool render() override;
 
@@ -107,7 +108,7 @@ class QgsVectorLayerRenderer : public QgsMapLayerRenderer
 
     QgsRenderContext &mContext;
 
-    QgsVectorLayerRendererInterruptionChecker mInterruptionChecker;
+    std::unique_ptr< QgsVectorLayerRendererInterruptionChecker > mInterruptionChecker;
 
     //! The rendered layer
     QgsVectorLayer *mLayer = nullptr;
