Fix rollback on large tables when attr table is opened

Author: elpaso

python/core/auto_generated/qgsapplication.sip.in

@@ -821,20 +821,6 @@ Set translation
 %Docstring
 Emits the signal to collect all the strings of .qgs to be included in ts file
 
-.. versionadded:: 3.4
-%End
-
-    void blockAttributeTableUpdates( const QgsVectorLayer *layer );
-%Docstring
-Emits the signal to block updates for attribute tables connected a particular ``layer``
-
-.. versionadded:: 3.4
-%End
-
-    void unblockAttributeTableUpdates( const QgsVectorLayer *layer );
-%Docstring
-Emits the signal to unblock updates for attribute tables connected a particular ``layer``
-
 .. versionadded:: 3.4
 %End
 
@@ -864,20 +850,6 @@ Emitted whenever a custom global variable changes.
 Emitted when project strings which require translation are being collected for inclusion in a .ts file.
 In order to register translatable strings, connect to this signal and register the strings within the specified ``translationContext``.
 
-.. versionadded:: 3.4
-%End
-
-    void attributeTableUpdateBlocked( const QgsVectorLayer *layer );
-%Docstring
-Emitted when attribute table updates for a particular ``layer`` must be blocked
-
-.. versionadded:: 3.4
-%End
-
-    void attributeTableUpdateUnblocked( const QgsVectorLayer *layer );
-%Docstring
-Emitted when all attribute table updates for a particular ``layer`` must be unblocked
-
 .. versionadded:: 3.4
 %End
 

python/core/auto_generated/qgsvectorlayer.sip.in

@@ -2371,6 +2371,13 @@ Is emitted, before changes are committed to the data provider
     void beforeRollBack();
 %Docstring
 Is emitted, before changes are rolled back
+%End
+
+    void afterRollBack();
+%Docstring
+Is emitted, after changes are rolled back
+
+.. versionadded:: 3.4
 %End
 
     void attributeAdded( int idx );

src/app/qgisapp.cpp

@@ -9189,6 +9189,17 @@ bool QgisApp::toggleEditing( QgsMapLayer *layer, bool allowCancel )
   return res;
 }
 
+
+void QgisApp::unblockAttributeTableUpdates( const QgsVectorLayer *layer )
+{
+  emit attributeTableUpdateUnblocked( layer );
+}
+
+void QgisApp::blockAttributeTableUpdates( const QgsVectorLayer *layer )
+{
+  emit attributeTableUpdateBlocked( layer );
+}
+
 void QgisApp::saveActiveLayerEdits()
 {
   saveEdits( activeLayer(), true, true );

src/app/qgisapp.h

@@ -1008,6 +1008,20 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
      */
     void triggerCrashHandler();
 
+    /**
+     * Emits the signal to block updates for attribute tables connected a particular \a layer
+     *
+     * \since QGIS 3.4
+     */
+    void blockAttributeTableUpdates( const QgsVectorLayer *layer );
+
+    /**
+     * Emits the signal to unblock updates for attribute tables connected a particular \a layer
+     *
+     * \since QGIS 3.4
+     */
+    void unblockAttributeTableUpdates( const QgsVectorLayer *layer );
+
   protected:
 
     //! Handle state changes (WindowTitleChange)
@@ -1741,6 +1755,20 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
      */
     void activeLayerChanged( QgsMapLayer *layer );
 
+    /**
+     * Emitted when attribute table updates for a particular \a layer must be blocked
+     *
+     * \since QGIS 3.4
+     */
+    void attributeTableUpdateBlocked( const QgsVectorLayer *layer );
+
+    /**
+     * Emitted when all attribute table updates for a particular \a layer must be unblocked
+     *
+     * \since QGIS 3.4
+     */
+    void attributeTableUpdateUnblocked( const QgsVectorLayer *layer );
+
   private:
     void startProfile( const QString &name );
     void endProfile();

src/app/qgsattributetabledialog.cpp

@@ -112,16 +112,19 @@ QgsAttributeTableDialog::QgsAttributeTableDialog( QgsVectorLayer *layer, QgsAttr
   connect( mMainView, &QgsDualView::showContextMenuExternally, this, &QgsAttributeTableDialog::showContextMenu );
 
   // Block/unblock table updates (feature cache signals)
-  connect( QgsApplication::instance(), &QgsApplication::attributeTableUpdateBlocked, [ = ]( const QgsVectorLayer * layer )
+  connect( QgisApp::instance(), &QgisApp::attributeTableUpdateBlocked, [ = ]( const QgsVectorLayer * layer )
   {
     if ( layer == mLayer )
       this->blockCacheUpdateSignals( true );
   } );
-  connect( QgsApplication::instance(), &QgsApplication::attributeTableUpdateUnblocked, [ = ]( const QgsVectorLayer * layer )
+  connect( QgisApp::instance(), &QgisApp::attributeTableUpdateUnblocked, [ = ]( const QgsVectorLayer * layer )
   {
     if ( layer == mLayer )
       this->blockCacheUpdateSignals( false );
   } );
+  // Massive rollbacks can also freeze the GUI due to the feature cache signals
+  connect( mLayer, &QgsVectorLayer::beforeRollBack, [ = ] { this->blockCacheUpdateSignals( true ); } );
+  connect( mLayer, &QgsVectorLayer::afterRollBack, [ = ] { this->blockCacheUpdateSignals( false ); } );
 
   const QgsFields fields = mLayer->fields();
   for ( const QgsField &field : fields )

src/app/qgsfieldcalculator.cpp

@@ -269,7 +269,7 @@ void QgsFieldCalculator::accept()
 
     // Begin feature modifications, block updates for attr tables
     // connected to this layer
-    QgsApplication::instance()->blockAttributeTableUpdates( mVectorLayer );
+    QgisApp::instance()->blockAttributeTableUpdates( mVectorLayer );
 
     //go through all the features and change the new attribute
     QgsFeature feature;
@@ -321,7 +321,7 @@ void QgsFieldCalculator::accept()
       rownum++;
     }
 
-    QgsApplication::instance()->unblockAttributeTableUpdates( mVectorLayer );
+    QgisApp::instance()->unblockAttributeTableUpdates( mVectorLayer );
 
     QApplication::restoreOverrideCursor();
 

src/core/qgsapplication.cpp

@@ -1535,15 +1535,6 @@ void QgsApplication::collectTranslatableObjects( QgsTranslationContext *translat
   emit requestForTranslatableObjects( translationContext );
 }
 
-void QgsApplication::unblockAttributeTableUpdates( const QgsVectorLayer *layer )
-{
-  emit attributeTableUpdateUnblocked( layer );
-}
-
-void QgsApplication::blockAttributeTableUpdates( const QgsVectorLayer *layer )
-{
-  emit attributeTableUpdateBlocked( layer );
-}
 
 QString QgsApplication::nullRepresentation()
 {

src/core/qgsapplication.h

@@ -758,20 +758,6 @@ class CORE_EXPORT QgsApplication : public QApplication
      */
     void collectTranslatableObjects( QgsTranslationContext *translationContext );
 
-    /**
-     * Emits the signal to block updates for attribute tables connected a particular \a layer
-     *
-     * \since QGIS 3.4
-     */
-    void blockAttributeTableUpdates( const QgsVectorLayer *layer );
-
-    /**
-     * Emits the signal to unblock updates for attribute tables connected a particular \a layer
-     *
-     * \since QGIS 3.4
-     */
-    void unblockAttributeTableUpdates( const QgsVectorLayer *layer );
-
 
 #ifdef SIP_RUN
     SIP_IF_FEATURE( ANDROID )
@@ -804,20 +790,6 @@ class CORE_EXPORT QgsApplication : public QApplication
      */
     void requestForTranslatableObjects( QgsTranslationContext *translationContext );
 
-    /**
-     * Emitted when attribute table updates for a particular \a layer must be blocked
-     *
-     * \since QGIS 3.4
-     */
-    void attributeTableUpdateBlocked( const QgsVectorLayer *layer );
-
-    /**
-     * Emitted when all attribute table updates for a particular \a layer must be unblocked
-     *
-     * \since QGIS 3.4
-     */
-    void attributeTableUpdateUnblocked( const QgsVectorLayer *layer );
-
 
   private:
 

src/core/qgsvectorlayer.cpp

@@ -2973,6 +2973,8 @@ bool QgsVectorLayer::rollBack( bool deleteBuffer )
 
   mEditBuffer->rollBack();
 
+  emit afterRollBack();
+
   if ( isModified() )
   {
     // new undo stack roll back method

src/core/qgsvectorlayer.h

@@ -2167,6 +2167,12 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
     //! Is emitted, before changes are rolled back
     void beforeRollBack();
 
+    /**
+     * Is emitted, after changes are rolled back
+     * \since QGIS 3.4
+     */
+    void afterRollBack();
+
     /**
      * Will be emitted, when a new attribute has been added to this vector layer.
      * Applies only to types QgsFields::OriginEdit, QgsFields::OriginProvider and QgsFields::OriginExpression