Merge pull request #4230 from nyalldawson/cache_table_218

Backport attribute table optimisations from 3.0

python/core/qgsvectorlayercache.sip

@@ -33,19 +33,10 @@ class QgsVectorLayerCache : QObject
      */
     int cacheSize();
 
-    /**
-     * Enable or disable the caching of geometries
-     *
-     * @param cacheGeometry    Enable or disable the caching of geometries
-     */
     void setCacheGeometry( bool cacheGeometry );
 
+    bool cacheGeometry() const;
 
-    /**
-     * Set the subset of attributes to be cached
-     *
-     * @param attributes   The attributes to be cached
-     */
     void setCacheSubsetOfAttributes( const QgsAttributeList& attributes );
 
     /**

python/gui/attributetable/qgsdualview.sip

@@ -32,16 +32,8 @@ class QgsDualView : QStackedWidget
     explicit QgsDualView( QWidget* parent /TransferThis/ = 0 );
     virtual ~QgsDualView();
 
-    /**
-     * Has to be called to initialize the dual view.
-     *
-     * @param layer      The layer which should be used to fetch features
-     * @param mapCanvas  The mapCanvas (used for the FilterMode
-     *                   {@link QgsAttributeTableFilterModel::ShowVisible}
-     * @param request    Use a modified request to limit the shown features
-     * @param context    The context in which this view is shown
-     */
-    void init( QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, const QgsFeatureRequest& request = QgsFeatureRequest(), const QgsAttributeEditorContext& context = QgsAttributeEditorContext() );
+    void init( QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, const QgsFeatureRequest& request = QgsFeatureRequest(), const QgsAttributeEditorContext& context = QgsAttributeEditorContext(),
+               bool loadFeatures = true );
 
     /**
      * Change the current view mode.

src/app/qgsattributetabledialog.cpp

@@ -131,8 +131,10 @@ QgsAttributeTableDialog::QgsAttributeTableDialog( QgsVectorLayer *theLayer, QWid
   mEditorContext.setVectorLayerTools( QgisApp::instance()->vectorLayerTools() );
 
   QgsFeatureRequest r;
+  bool needsGeom = false;
+  QgsAttributeTableFilterModel::FilterMode initialMode = static_cast< QgsAttributeTableFilterModel::FilterMode>( settings.value( QString( "/qgis/attributeTableBehaviour" ), QgsAttributeTableFilterModel::ShowAll ).toInt() );
   if ( mLayer->geometryType() != QGis::NoGeometry &&
-       settings.value( "/qgis/attributeTableBehaviour", QgsAttributeTableFilterModel::ShowAll ).toInt() == QgsAttributeTableFilterModel::ShowVisible )
+       initialMode == QgsAttributeTableFilterModel::ShowVisible )
   {
     QgsMapCanvas *mc = QgisApp::instance()->mapCanvas();
     QgsRectangle extent( mc->mapSettings().mapToLayerCoordinates( theLayer, mc->extent() ) );
@@ -144,10 +146,18 @@ QgsAttributeTableDialog::QgsAttributeTableDialog( QgsVectorLayer *theLayer, QWid
     delete g;
 
     mActionShowAllFilter->setText( tr( "Show All Features In Initial Canvas Extent" ) );
+    needsGeom = true;
   }
+  else if ( initialMode == QgsAttributeTableFilterModel::ShowSelected )
+  {
+    if ( theLayer->selectedFeatureCount() > 0 )
+      r.setFilterFids( theLayer->selectedFeaturesIds() );
+  }
+  if ( !needsGeom )
+    r.setFlags( QgsFeatureRequest::NoGeometry );
 
   // Initialize dual view
-  mMainView->init( mLayer, QgisApp::instance()->mapCanvas(), r, mEditorContext );
+  mMainView->init( mLayer, QgisApp::instance()->mapCanvas(), r, mEditorContext, false );
 
   QgsAttributeTableConfig config = mLayer->attributeTableConfig();
   mMainView->setAttributeTableConfig( config );
@@ -322,7 +332,7 @@ void QgsAttributeTableDialog::updateTitle()
   QWidget *w = mDock ? qobject_cast<QWidget*>( mDock ) : qobject_cast<QWidget*>( this );
   w->setWindowTitle( tr( " %1 :: Features total: %2, filtered: %3, selected: %4%5" )
                      .arg( mLayer->name() )
-                     .arg( mMainView->featureCount() )
+                     .arg( qMax( static_cast< long >( mMainView->featureCount() ), mLayer->featureCount() ) ) // layer count may be estimated, so use larger of the two
                      .arg( mMainView->filteredFeatureCount() )
                      .arg( mLayer->selectedFeatureCount() )
                      .arg( mRubberBand ? tr( ", spatially limited" ) : "" )

src/core/qgsvectorlayercache.cpp

@@ -58,7 +58,9 @@ int QgsVectorLayerCache::cacheSize()
 
 void QgsVectorLayerCache::setCacheGeometry( bool cacheGeometry )
 {
-  mCacheGeometry = cacheGeometry && mLayer->hasGeometryType();
+  bool shouldCacheGeometry = cacheGeometry && mLayer->hasGeometryType();
+  bool mustInvalidate = shouldCacheGeometry && !mCacheGeometry; // going from no geometry -> geometry, so have to clear existing cache entries
+  mCacheGeometry = shouldCacheGeometry;
   if ( cacheGeometry )
   {
     connect( mLayer, SIGNAL( geometryChanged( QgsFeatureId, QgsGeometry& ) ), SLOT( geometryChanged( QgsFeatureId, QgsGeometry& ) ) );
@@ -67,6 +69,10 @@ void QgsVectorLayerCache::setCacheGeometry( bool cacheGeometry )
   {
     disconnect( mLayer, SIGNAL( geometryChanged( QgsFeatureId, QgsGeometry& ) ), this, SLOT( geometryChanged( QgsFeatureId, QgsGeometry& ) ) );
   }
+  if ( mustInvalidate )
+  {
+    invalidate();
+  }
 }
 
 void QgsVectorLayerCache::setCacheSubsetOfAttributes( const QgsAttributeList& attributes )
@@ -231,7 +237,7 @@ void QgsVectorLayerCache::attributeAdded( int field )
 {
   Q_UNUSED( field )
   mCachedAttributes.append( field );
-  mCache.clear();
+  invalidate();
 }
 
 void QgsVectorLayerCache::attributeDeleted( int field )
@@ -267,6 +273,7 @@ void QgsVectorLayerCache::layerDeleted()
 void QgsVectorLayerCache::invalidate()
 {
   mCache.clear();
+  mFullCache = false;
   emit invalidated();
 }
 

src/core/qgsvectorlayercache.h

@@ -103,9 +103,16 @@ class CORE_EXPORT QgsVectorLayerCache : public QObject
      * Enable or disable the caching of geometries
      *
      * @param cacheGeometry    Enable or disable the caching of geometries
+     * @see cacheGeometry()
      */
     void setCacheGeometry( bool cacheGeometry );
 
+    /**
+     * Returns true if the cache will fetch and cache feature geometries.
+     * @note added in QGIS 3.0
+     * @see setCacheGeometry()
+     */
+    bool cacheGeometry() const { return mCacheGeometry; }
 
     /**
      * Set the subset of attributes to be cached
@@ -131,6 +138,8 @@ class CORE_EXPORT QgsVectorLayerCache : public QObject
      * be used for slow data sources, be aware, that the call to this method might take a long time.
      *
      * @param fullCache   True: enable full caching, False: disable full caching
+     * @note when a cache is invalidated() (e.g. by adding an attribute to a layer) this setting
+     * is reset. A full cache rebuild must be performed by calling setFullCache( true ) again.
      * @see hasFullCache()
      */
     void setFullCache( bool fullCache );
@@ -273,7 +282,9 @@ class CORE_EXPORT QgsVectorLayerCache : public QObject
     void featureAdded( QgsFeatureId fid );
 
     /**
-     * The cache has been invalidated and cleared.
+     * The cache has been invalidated and cleared. Note that when a cache is invalidated
+     * the fullCache() setting will be cleared, and a full cache rebuild via setFullCache( true )
+     * will need to be performed.
      */
     void invalidated();