optional fids counting

qgis · Nov 4, 2019 · 38fb55e · 38fb55e
1 parent 78afeea
commit 38fb55e
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Showing 6 changed files with 27 additions and 15 deletions.
diff --git a/python/core/auto_generated/qgsvectorlayer.sip.in b/python/core/auto_generated/qgsvectorlayer.sip.in
@@ -1042,13 +1042,15 @@ if the geometry type of the new data source matches the current geometry type of
     virtual QString loadDefaultStyle( bool &resultFlag /Out/ ) ${SIP_FINAL};
 
 
-    QgsVectorLayerFeatureCounter *countSymbolFeatures();
+    QgsVectorLayerFeatureCounter *countSymbolFeatures( bool storeSymbolFids = false );
 %Docstring
 Count features for symbols.
 The method will return the feature counter task. You will need to
 connect to the symbolFeatureCountMapChanged() signal to be
 notified when the freshly updated feature counts are ready.
 
+:param storeSymbolFids: If ``True`` will gather the feature ids (fids) per symbol, otherwise only the count. Default ``False``.
+
 .. note::
 
    If the count features for symbols has been already done a

diff --git a/python/core/auto_generated/qgsvectorlayerfeaturecounter.sip.in b/python/core/auto_generated/qgsvectorlayerfeaturecounter.sip.in
@@ -24,9 +24,13 @@ QgsVectorLayer.countSymbolFeatures() and connect to the signal
 %End
   public:
 
-    QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context = QgsExpressionContext() );
+    QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context = QgsExpressionContext(), bool storeSymbolFids = false );
 %Docstring
 Create a new feature counter for ``layer``.
+
+:param layer: Target QgsVectorLayer to perform counting on.
+:param context: Specific QgsExpressionContext to use during the rendering step.
+:param storeSymbolFids: If ``True`` will store the feature ids (fids), otherwise will only count the number of features per symbol. Default ``False``.
 %End
 
 

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -730,10 +730,9 @@ QgsFeatureIds QgsVectorLayer::symbolFeatureIds( const QString &legendKey ) const
 
   return mSymbolFeatureIdMap.value( legendKey, QgsFeatureIds() );
 }
-
-QgsVectorLayerFeatureCounter *QgsVectorLayer::countSymbolFeatures()
+QgsVectorLayerFeatureCounter *QgsVectorLayer::countSymbolFeatures( bool storeSymbolFids )
 {
-  if ( mSymbolFeatureCounted || mFeatureCounter )
+  if ( ( mSymbolFeatureCounted || mFeatureCounter ) && !( storeSymbolFids && mSymbolFeatureIdMap.isEmpty() ) )
     return mFeatureCounter;
 
   mSymbolFeatureCountMap.clear();
@@ -755,12 +754,11 @@ QgsVectorLayerFeatureCounter *QgsVectorLayer::countSymbolFeatures()
     return mFeatureCounter;
   }
 
-  if ( !mFeatureCounter )
+  if ( !mFeatureCounter || ( mFeatureCounter && ( storeSymbolFids && mSymbolFeatureIdMap.isEmpty() ) ) )
   {
-    mFeatureCounter = new QgsVectorLayerFeatureCounter( this );
-    connect( mFeatureCounter, &QgsTask::taskCompleted, this, &QgsVectorLayer::onFeatureCounterCompleted );
-    connect( mFeatureCounter, &QgsTask::taskTerminated, this, &QgsVectorLayer::onFeatureCounterTerminated );
-
+    mFeatureCounter = new QgsVectorLayerFeatureCounter( this, QgsExpressionContext(), storeSymbolFids );
+    connect( mFeatureCounter, &QgsTask::taskCompleted, this, &QgsVectorLayer::onFeatureCounterCompleted, Qt::UniqueConnection );
+    connect( mFeatureCounter, &QgsTask::taskTerminated, this, &QgsVectorLayer::onFeatureCounterTerminated, Qt::UniqueConnection );
     QgsApplication::taskManager()->addTask( mFeatureCounter );
   }
 

diff --git a/src/core/qgsvectorlayer.h b/src/core/qgsvectorlayer.h
@@ -1082,13 +1082,14 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * connect to the symbolFeatureCountMapChanged() signal to be
      * notified when the freshly updated feature counts are ready.
      *
+     * \param storeSymbolFids If TRUE will gather the feature ids (fids) per symbol, otherwise only the count. Default FALSE.
      * \note If the count features for symbols has been already done a
      *       NULLPTR is returned. If you need to wait for the results,
      *       you can call waitForFinished() on the feature counter.
      *
      * \since This is asynchronous since QGIS 3.0
      */
-    QgsVectorLayerFeatureCounter *countSymbolFeatures();
+    QgsVectorLayerFeatureCounter *countSymbolFeatures( bool storeSymbolFids = false );
 
     /**
      * Sets the string (typically sql) used to define a subset of the layer

diff --git a/src/core/qgsvectorlayerfeaturecounter.cpp b/src/core/qgsvectorlayerfeaturecounter.cpp
@@ -17,11 +17,12 @@
 #include "qgsvectorlayer.h"
 #include "qgsfeatureid.h"
 
-QgsVectorLayerFeatureCounter::QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context )
+QgsVectorLayerFeatureCounter::QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context, bool storeSymbolFids )
   : QgsTask( tr( "Counting features in %1" ).arg( layer->name() ), QgsTask::CanCancel )
   , mSource( new QgsVectorLayerFeatureSource( layer ) )
   , mRenderer( layer->renderer()->clone() )
   , mExpressionContext( context )
+  , mWithFids( storeSymbolFids )
   , mFeatureCount( layer->featureCount() )
 {
   if ( !mExpressionContext.scopeCount() )
@@ -40,7 +41,8 @@ bool QgsVectorLayerFeatureCounter::run()
   for ( ; symbolIt != symbolList.constEnd(); ++symbolIt )
   {
     mSymbolFeatureCountMap.insert( symbolIt->label(), 0 );
-    mSymbolFeatureIdMap.insert( symbolIt->label(), QgsFeatureIds() );
+    if ( mWithFids )
+      mSymbolFeatureIdMap.insert( symbolIt->label(), QgsFeatureIds() );
   }
 
   // If there are no features to be counted, we can spare us the trouble
@@ -74,7 +76,8 @@ bool QgsVectorLayerFeatureCounter::run()
       for ( const QString &key : featureKeyList )
       {
         mSymbolFeatureCountMap[key] += 1;
-        mSymbolFeatureIdMap[key].insert( f.id() );
+        if ( mWithFids )
+          mSymbolFeatureIdMap[key].insert( f.id() );
       }
       ++featuresCounted;
 

diff --git a/src/core/qgsvectorlayerfeaturecounter.h b/src/core/qgsvectorlayerfeaturecounter.h
@@ -38,8 +38,11 @@ class CORE_EXPORT QgsVectorLayerFeatureCounter : public QgsTask
 
     /**
      * Create a new feature counter for \a layer.
+     * \param layer Target QgsVectorLayer to perform counting on.
+     * \param context Specific QgsExpressionContext to use during the rendering step.
+     * \param storeSymbolFids If TRUE will store the feature ids (fids), otherwise will only count the number of features per symbol. Default FALSE.
      */
-    QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context = QgsExpressionContext() );
+    QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context = QgsExpressionContext(), bool storeSymbolFids = false );
 
 
     /**
@@ -92,6 +95,7 @@ class CORE_EXPORT QgsVectorLayerFeatureCounter : public QgsTask
     QgsExpressionContext mExpressionContext;
     QHash<QString, long> mSymbolFeatureCountMap;
     QHash<QString, QgsFeatureIds> mSymbolFeatureIdMap;
+    bool mWithFids = false;
     int mFeatureCount;
 
 };