Allow to filter joined fields with a virtual layer

python/core/core.sip

@@ -145,6 +145,7 @@
 %Include qgsvisibilitypresetcollection.sip
 %Include qgslayerdefinition.sip
 %Include qgsvirtuallayerdefinition.sip
+%Include qgsvirtuallayerdefinitionutils.sip
 %Include qgsxmlutils.sip
 
 %Include auth/qgsauthcertutils.sip

python/core/layertree/qgslayertreeutils.sip

@@ -44,4 +44,11 @@ class QgsLayerTreeUtils
     static QString legendFilterByExpression( const QgsLayerTreeLayer& layer, bool* enabled = 0 );
     //! Test if one of the layers in a group has an expression filter
     static bool hasLegendFilterExpression( const QgsLayerTreeGroup& group );
+
+    //! Insert a QgsMapLayer just below another one
+    //! @param group the tree group where layers are (can be the root group)
+    //! @param refLayer the reference layer
+    //! @param layerToInsert the new layer to insert just below the reference layer
+    //! @returns the new tree layer
+    static QgsLayerTreeLayer* insertLayerBelow( QgsLayerTreeGroup* group, const QgsMapLayer* refLayer, QgsMapLayer* layerToInsert );
 };

python/core/qgsvirtuallayerdefinitionutils.sip

@@ -0,0 +1,12 @@
+/**
+ * Utils class for QgsVirtualLayerDefinition
+ */
+class QgsVirtualLayerDefinitionUtils
+{
+%TypeHeaderCode
+#include <qgsvirtuallayerdefinitionutils.h>
+%End
+  public:
+    //! Get a virtual layer definition from a vector layer where vector joins are replaced by SQL LEFT JOINs
+    static QgsVirtualLayerDefinition fromJoinedLayer( QgsVectorLayer* joinedLayer );
+};

src/app/qgisapp.cpp

@@ -230,6 +230,8 @@
 #include "qgsmaprendererparalleljob.h"
 #include "qgsversioninfo.h"
 #include "qgslegendfilterbutton.h"
+#include "qgsvirtuallayerdefinition.h"
+#include "qgsvirtuallayerdefinitionutils.h"
 
 #include "qgssublayersdialog.h"
 #include "ogr/qgsopenvectorlayerdialog.h"
@@ -3793,37 +3795,11 @@ void QgisApp::replaceSelectedVectorLayer( const QString& uri, const QString& lay
     return;
 
   QgsMapLayerRegistry::instance()->addMapLayer( newLayer, /*addToLegend*/ false, /*takeOwnership*/ true );
-  // copy symbology, if possible
-  if ( oldLayer->geometryType() == newLayer->geometryType() )
-  {
-    QDomImplementation DomImplementation;
-    QDomDocumentType documentType =
-      DomImplementation.createDocumentType(
-        "qgis", "http://mrcc.com/qgis.dtd", "SYSTEM" );
-    QDomDocument doc( documentType );
-    QDomElement rootNode = doc.createElement( "qgis" );
-    rootNode.setAttribute( "version", QString( "%1" ).arg( QGis::QGIS_VERSION ) );
-    doc.appendChild( rootNode );
-    QString errorMsg;
-    oldLayer->writeSymbology( rootNode, doc, errorMsg );
-    newLayer->readSymbology( rootNode, errorMsg );
-  }
+  duplicateVectorStyle( oldLayer, newLayer );
 
-  // get the index in its parent for the current layer
-  QgsLayerTreeLayer* inTree = QgsProject::instance()->layerTreeRoot()->findLayer( oldLayer->id() );
-  int idx = 0;
-  foreach ( QgsLayerTreeNode* vl, inTree->parent()->children() )
-  {
-    if ( vl->nodeType() == QgsLayerTreeNode::NodeLayer && static_cast<QgsLayerTreeLayer*>( vl )->layer() == oldLayer )
-    {
-      break;
-    }
-    idx++;
-  }
-  // insert the new layer
-  QgsLayerTreeGroup* parent = static_cast<QgsLayerTreeGroup*>( inTree->parent() ) ? static_cast<QgsLayerTreeGroup*>( inTree->parent() ) : QgsProject::instance()->layerTreeRoot();
-  parent->insertLayer( idx, newLayer );
-  // remove the current layer
+  // insert the new layer just below the old one
+  QgsLayerTreeUtils::insertLayerBelow( QgsProject::instance()->layerTreeRoot(), oldLayer, newLayer );
+  // and remove the old layer
   QgsMapLayerRegistry::instance()->removeMapLayer( oldLayer );
 } // QgisApp:replaceSelectedVectorLayer
 
@@ -7431,12 +7407,58 @@ QList<QgsMapLayer *> QgisApp::editableLayers( bool modified ) const
   return editLayers;
 }
 
+void QgisApp::duplicateVectorStyle( QgsVectorLayer* srcLayer, QgsVectorLayer* destLayer )
+{
+  // copy symbology, if possible
+  if ( srcLayer->geometryType() == destLayer->geometryType() )
+  {
+    QDomImplementation DomImplementation;
+    QDomDocumentType documentType =
+      DomImplementation.createDocumentType(
+        "qgis", "http://mrcc.com/qgis.dtd", "SYSTEM" );
+    QDomDocument doc( documentType );
+    QDomElement rootNode = doc.createElement( "qgis" );
+    rootNode.setAttribute( "version", QString( "%1" ).arg( QGis::QGIS_VERSION ) );
+    doc.appendChild( rootNode );
+    QString errorMsg;
+    srcLayer->writeSymbology( rootNode, doc, errorMsg );
+    destLayer->readSymbology( rootNode, errorMsg );
+  }
+}
+
 void QgisApp::layerSubsetString()
 {
   QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( activeLayer() );
   if ( !vlayer )
     return;
 
+  if ( !vlayer->vectorJoins().isEmpty() )
+  {
+    if ( QMessageBox::question( NULL, tr( "Filter on joined fields" ),
+                                tr( "You are about to set a subset filter on a layer that has joined fields. "
+                                    "Joined fields cannot be filtered, unless you convert the layer to a virtual layer first. "
+                                    "Would you like to create a virtual layer out of this layer first ?" ),
+                                QMessageBox::Yes | QMessageBox::No ) == QMessageBox::Yes )
+    {
+      QgsVirtualLayerDefinition def = QgsVirtualLayerDefinitionUtils::fromJoinedLayer( vlayer );
+      QgsVectorLayer* newLayer = new QgsVectorLayer( def.toString(), vlayer->name() + " (virtual)", "virtual" );
+      if ( newLayer->isValid() )
+      {
+        duplicateVectorStyle( vlayer, newLayer );
+        QgsMapLayerRegistry::instance()->addMapLayer( newLayer, /*addToLegend*/ false, /*takeOwnership*/ true );
+        QgsLayerTreeUtils::insertLayerBelow( QgsProject::instance()->layerTreeRoot(), vlayer, newLayer );
+        mLayerTreeView->setCurrentLayer( newLayer );
+        // hide the old layer
+        QgsProject::instance()->layerTreeRoot()->findLayer( vlayer->id() )->setVisible( Qt::Unchecked );
+        vlayer = newLayer;
+      }
+      else
+      {
+        delete newLayer;
+      }
+    }
+  }
+
   // launch the query builder
   QgsQueryBuilder *qb = new QgsQueryBuilder( vlayer, this );
   QString subsetBefore = vlayer->subsetString();

src/app/qgisapp.h

@@ -1402,6 +1402,9 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
     /** Apply raster brightness */
     void adjustBrightnessContrast( int delta, bool updateBrightness = true );
 
+    /** Copy a vector style from a layer to another one, if they have the same geometry type */
+    void duplicateVectorStyle( QgsVectorLayer* srcLayer, QgsVectorLayer* destLayer );
+
     QgisAppStyleSheet *mStyleSheetBuilder;
 
     // actions for menus and toolbars -----------------

src/core/CMakeLists.txt

@@ -205,6 +205,7 @@ SET(QGIS_CORE_SRCS
   qgsvectorsimplifymethod.cpp
   qgsvisibilitypresetcollection.cpp
   qgsvirtuallayerdefinition.cpp
+  qgsvirtuallayerdefinitionutils.cpp
   qgsxmlutils.cpp
   qgsslconnect.cpp
   qgslocalec.cpp

src/core/layertree/qgslayertreeutils.cpp

@@ -394,3 +394,21 @@ bool QgsLayerTreeUtils::hasLegendFilterExpression( const QgsLayerTreeGroup& grou
   }
   return false;
 }
+
+QgsLayerTreeLayer* QgsLayerTreeUtils::insertLayerBelow( QgsLayerTreeGroup* group, const QgsMapLayer* refLayer, QgsMapLayer* layerToInsert )
+{
+  // get the index of the reflayer
+  QgsLayerTreeLayer* inTree = group->findLayer( refLayer->id() );
+  int idx = 0;
+  foreach ( QgsLayerTreeNode* vl, inTree->parent()->children() )
+  {
+    if ( vl->nodeType() == QgsLayerTreeNode::NodeLayer && static_cast<QgsLayerTreeLayer*>( vl )->layer() == refLayer )
+    {
+      break;
+    }
+    idx++;
+  }
+  // insert the new layer
+  QgsLayerTreeGroup* parent = static_cast<QgsLayerTreeGroup*>( inTree->parent() ) ? static_cast<QgsLayerTreeGroup*>( inTree->parent() ) : group;
+  return parent->insertLayer( idx, layerToInsert );
+}

src/core/layertree/qgslayertreeutils.h

@@ -27,6 +27,7 @@ class QStringList;
 class QgsLayerTreeNode;
 class QgsLayerTreeGroup;
 class QgsLayerTreeLayer;
+class QgsMapLayer;
 
 /**
  * Assorted functions for dealing with layer trees.
@@ -72,6 +73,13 @@ class CORE_EXPORT QgsLayerTreeUtils
     static QString legendFilterByExpression( const QgsLayerTreeLayer& layer, bool* enabled = nullptr );
     //! Test if one of the layers in a group has an expression filter
     static bool hasLegendFilterExpression( const QgsLayerTreeGroup& group );
+
+    //! Insert a QgsMapLayer just below another one
+    //! @param group the tree group where layers are (can be the root group)
+    //! @param refLayer the reference layer
+    //! @param layerToInsert the new layer to insert just below the reference layer
+    //! @returns the new tree layer
+    static QgsLayerTreeLayer* insertLayerBelow( QgsLayerTreeGroup* group, const QgsMapLayer* refLayer, QgsMapLayer* layerToInsert );
 };
 
 #endif // QGSLAYERTREEUTILS_H

src/core/qgsvirtuallayerdefinition.cpp

@@ -19,6 +19,8 @@ email                : hugo dot mercier at oslandia dot com
 #include <QStringList>
 
 #include "qgsvirtuallayerdefinition.h"
+#include "qgsvectorlayer.h"
+#include "qgsvectordataprovider.h"
 
 QgsVirtualLayerDefinition::QgsVirtualLayerDefinition( const QString& filePath ) :
     mFilePath( filePath ),

src/core/qgsvirtuallayerdefinitionutils.cpp

@@ -0,0 +1,80 @@
+/***************************************************************************
+                qgsvirtuallayerdefinitionutils.cpp
+begin                : Jan 2016
+copyright            : (C) 2016 Hugo Mercier, Oslandia
+email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsvirtuallayerdefinitionutils.h"
+#include "qgsvectorlayer.h"
+#include "qgsvectordataprovider.h"
+
+QgsVirtualLayerDefinition QgsVirtualLayerDefinitionUtils::fromJoinedLayer( QgsVectorLayer* layer )
+{
+  QgsVirtualLayerDefinition def;
+
+  QStringList leftJoins;
+  QStringList columns;
+
+  columns << "t.*"; // columns from the main layer
+
+  // look for the uid
+  const QgsFields& fields = layer->dataProvider()->fields();
+  {
+    QgsAttributeList pk = layer->dataProvider()->pkAttributeIndexes();
+    if ( pk.size() == 1 )
+    {
+      def.setUid( fields.field( pk[0] ).name() );
+    }
+    else
+    {
+      // find an uid name
+      QString uid = "uid";
+      while ( fields.fieldNameIndex( uid ) != -1 )
+        uid += "_"; // add "_" each time this name already exists
+
+      // add a column
+      columns << "t.rowid AS " + uid;
+      def.setUid( uid );
+    }
+  }
+
+  int joinIdx = 0;
+  foreach ( const QgsVectorJoinInfo& join, layer->vectorJoins() )
+  {
+    QString joinName = QString( "j%1" ).arg( ++joinIdx );
+    QString prefix = join.prefix.isEmpty() ? layer->name() + "_" : join.prefix;
+
+    leftJoins << QString( "LEFT JOIN %1 AS %2 ON t.\"%3\"=%2.\"%5\"" ).arg( join.joinLayerId ).arg( joinName ).arg( join.joinFieldName ).arg( join.targetFieldName );
+    if ( join.joinFieldNamesSubset() )
+    {
+      foreach ( const QString& f, *join.joinFieldNamesSubset() )
+      {
+        columns << joinName + "." + f + " AS " + prefix + f;
+      }
+    }
+    else
+    {
+      const QgsFields& joinedFields = layer->dataProvider()->fields();
+      for ( int i = 0; i < joinedFields.count(); i++ )
+      {
+        const QgsField& f = joinedFields.field( i );
+        columns << joinName + "." + f.name() + " AS " + prefix + f.name();
+      }
+    }
+  }
+
+  QString query = "SELECT " + columns.join( ", " ) + " FROM " + layer->id() + " AS t " + leftJoins.join( " " );
+  def.setQuery( query );
+
+  return def;
+}

src/core/qgsvirtuallayerdefinitionutils.h

@@ -0,0 +1,34 @@
+/***************************************************************************
+                qgsvirtuallayerdefinitionutils.h
+begin                : Jan, 2016
+copyright            : (C) 2016 Hugo Mercier, Oslandia
+email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSVIRTUALLAYERDEFINITION_UTILS_H
+#define QGSVIRTUALLAYERDEFINITION_UTILS_H
+
+#include "qgsvirtuallayerdefinition.h"
+
+class QgsVectorLayer;
+
+/**
+ * Utils class for QgsVirtualLayerDefinition
+ */
+class CORE_EXPORT QgsVirtualLayerDefinitionUtils
+{
+  public:
+    //! Get a virtual layer definition from a vector layer where vector joins are replaced by SQL LEFT JOINs
+    static QgsVirtualLayerDefinition fromJoinedLayer( QgsVectorLayer* joinedLayer );
+};
+
+#endif

src/providers/virtual/qgsvirtuallayersourceselect.cpp

@@ -107,6 +107,9 @@ QgsVirtualLayerSourceSelect::QgsVirtualLayerSourceSelect( QWidget* parent, Qt::W
 
   apis->prepare();
   mQueryEdit->lexer()->setAPIs( apis );
+
+  mQueryEdit->setWrapMode( QsciScintilla::WrapWord );
+
 }
 
 QgsVirtualLayerSourceSelect::~QgsVirtualLayerSourceSelect()