Add group support for QLR files

Add class for handling QLR files. Add sip bindings

Funded by Nicholas Duggan

python/core/qgslayerdefinition.sip

@@ -0,0 +1,11 @@
+class CORE_EXPORT QgsLayerDefinition
+{
+%TypeHeaderCode
+#include <qgslayerdefinition.h>
+%End
+public:
+  static bool openLayerDefinition( const QString & path, QgsLayerTreeGroup* rootGroup, QString &errorMessage /Out/ );
+  static bool openLayerDefinition( QDomDocument doc, QgsLayerTreeGroup* rootGroup, QString &errorMessage /Out/ );
+  static bool exportLayerDefinition( QString path, QList<QgsLayerTreeNode*> selectedTreeNodes, QString &errorMessage /Out/ );
+};
+

src/app/qgisapp.cpp

@@ -138,6 +138,7 @@
 #include "qgsgpsinformationwidget.h"
 #include "qgsguivectorlayertools.h"
 #include "qgslabelinggui.h"
+#include "qgslayerdefinition.h"
 #include "qgslayertree.h"
 #include "qgslayertreemapcanvasbridge.h"
 #include "qgslayertreemodel.h"
@@ -4124,8 +4125,13 @@ void QgisApp::dxfExport()
 
 void QgisApp::openLayerDefinition( const QString & path )
 {
-  QList<QgsMapLayer*> layers = QgsMapLayer::fromLayerDefinitionFile( path );
-  QgsMapLayerRegistry::instance()->addMapLayers( layers );
+  QString errorMessage;
+  bool loaded = QgsLayerDefinition::loadLayerDefinition( path, QgsProject::instance()->layerTreeRoot(), errorMessage );
+  if ( !loaded )
+  {
+    QgsDebugMsg( errorMessage );
+    messageBar()->pushMessage( tr( "Error loading layer definition" ), errorMessage, QgsMessageBar::WARNING );
+  }
 }
 
 // Open the project file corresponding to the
@@ -5038,26 +5044,17 @@ void QgisApp::saveAsFile()
 
 void QgisApp::saveAsLayerDefinition()
 {
-  QList<QgsMapLayer*> layers = mLayerTreeView->selectedLayers();
-
-  if ( layers.isEmpty() )
-    return;
 
   QString path = QFileDialog::getSaveFileName( this, "Save as Layer Definition File", QDir::home().path(), "*.qlr" );
   QgsDebugMsg( path );
   if ( path.isEmpty() )
     return;
 
-  if ( !path.endsWith( ".qlr" ) )
-    path = path.append( ".qlr" );
-
-  QFile file( path );
-  QFileInfo fileinfo( file );
-  QDomDocument doc = QgsMapLayer::asLayerDefinition( layers, fileinfo.canonicalFilePath() );
-  if ( file.open( QFile::WriteOnly | QFile::Truncate ) )
+  QString errorMessage;
+  bool saved = QgsLayerDefinition::exportLayerDefinition( path, mLayerTreeView->selectedNodes(), errorMessage );
+  if ( !saved )
   {
-    QTextStream qlayerstream( &file );
-    doc.save( qlayerstream, 2 );
+    messageBar()->pushMessage( tr( "Error saving layer definintion file" ), errorMessage, QgsMessageBar::WARNING );
   }
 }
 

src/app/qgsapplayertreeviewmenuprovider.cpp

@@ -56,6 +56,8 @@ QMenu* QgsAppLayerTreeViewMenuProvider::createContextMenu()
       if ( mView->selectedNodes( true ).count() >= 2 )
         menu->addAction( actions->actionGroupSelected( menu ) );
 
+      menu->addAction( tr( "Save As Layer Definition File..." ), QgisApp::instance(), SLOT( saveAsLayerDefinition() ) );
+
       menu->addAction( actions->actionAddGroup( menu ) );
     }
     else if ( QgsLayerTree::isLayer( node ) )

src/core/CMakeLists.txt

@@ -95,6 +95,7 @@ SET(QGIS_CORE_SRCS
   qgsgeometryvalidator.cpp
   qgsgml.cpp
   qgsgmlschema.cpp
+  qgslayerdefinition.cpp
   qgslabel.cpp
   qgslabelattributes.cpp
   qgslabelsearchtree.cpp
@@ -480,6 +481,7 @@ SET(QGIS_CORE_HDRS
   qgsfontutils.h
   qgsgeometry.h
   qgsgeometrycache.h
+  qgslayerdefinition.h
   qgslabel.h
   qgslabelattributes.h
   qgslabelsearchtree.h

src/core/qgslayerdefinition.cpp

@@ -0,0 +1,122 @@
+#include <QDomNode>
+#include <QFileInfo>
+#include <QFile>
+#include <QDir>
+#include <QTextStream>
+
+#include "qgslogger.h"
+#include "qgsmaplayer.h"
+#include "qgslayertree.h"
+#include "qgsmaplayerregistry.h"
+#include "qgslayerdefinition.h"
+
+bool QgsLayerDefinition::loadLayerDefinition( const QString &path, QgsLayerTreeGroup *rootGroup, QString &errorMessage )
+{
+  QFile file( path );
+  if ( !file.open( QIODevice::ReadOnly ) )
+  {
+    errorMessage = QString( "Can not open file" );
+    return false;
+  }
+
+  QDomDocument doc;
+  QString message;
+  if ( !doc.setContent( &file, &message ) )
+  {
+    errorMessage = message;
+    return false;
+  }
+
+  QFileInfo fileinfo( file );
+  QDir::setCurrent( fileinfo.absoluteDir().path() );
+
+  return loadLayerDefinition( doc, rootGroup, errorMessage );
+}
+
+bool QgsLayerDefinition::loadLayerDefinition( QDomDocument doc, QgsLayerTreeGroup *rootGroup, QString &errorMessage )
+{
+  QgsLayerTreeGroup* root = new QgsLayerTreeGroup;
+  // We have to replace the IDs before we load them because it's too late once they are loaded
+  QDomNodeList ids = doc.elementsByTagName( "id" );
+  for ( int i = 0; i < ids.size(); ++i )
+  {
+    QDomNode idnode = ids.at( i );
+    QDomElement idElem = idnode.toElement();
+    QString oldid = idElem.text();
+    // Strip the date part because we will replace it.
+    QString layername = oldid.left( oldid.length() - 17 );
+    QDateTime dt = QDateTime::currentDateTime();
+    QString newid = layername + dt.toString( "yyyyMMddhhmmsszzz" );
+    idElem.firstChild().setNodeValue( newid );
+    QDomNodeList treeLayerNodes = doc.elementsByTagName( "layer-tree-layer" );
+
+    for ( int i = 0; i < treeLayerNodes.count(); ++i )
+    {
+      QDomNode layerNode = treeLayerNodes.at( i );
+      QDomElement layerElem = layerNode.toElement();
+      if ( layerElem.attribute( "id" ) == oldid )
+      {
+        layerNode.toElement().setAttribute( "id", newid );
+      }
+    }
+  }
+
+  QDomElement layerTreeElem = doc.documentElement().firstChildElement( "layer-tree-group" );
+  bool loadInLegend = true;
+  if ( !layerTreeElem.isNull() )
+  {
+    root->readChildrenFromXML( layerTreeElem );
+    loadInLegend = false;
+  }
+
+  QList<QgsMapLayer*> layers = QgsMapLayer::fromLayerDefinition( doc );
+  QgsMapLayerRegistry::instance()->addMapLayers( layers, loadInLegend );
+
+  QList<QgsLayerTreeNode*> nodes = root->children();
+  rootGroup->insertChildNodes( -1, nodes );
+  return true;
+
+}
+
+bool QgsLayerDefinition::exportLayerDefinition( QString path, QList<QgsLayerTreeNode*> selectedTreeNodes, QString &errorMessage )
+{
+  if ( !path.endsWith( ".qlr" ) )
+    path = path.append( ".qlr" );
+
+  QFile file( path );
+  QFileInfo fileinfo( file );
+
+  QDomDocument doc( "qgis-layer-definition" );
+  QDomElement qgiselm = doc.createElement( "qlr" );
+  doc.appendChild( qgiselm );
+  QList<QgsLayerTreeNode*> nodes =  selectedTreeNodes;
+  QgsLayerTreeGroup* root = new QgsLayerTreeGroup;
+  foreach ( QgsLayerTreeNode* node, nodes )
+  {
+    QgsLayerTreeNode* newnode = node->clone();
+    root->addChildNode( newnode );
+  }
+  root->writeXML( qgiselm );
+
+  QDomElement layerselm = doc.createElement( "maplayers" );
+  QList<QgsLayerTreeLayer*> layers = root->findLayers();
+  foreach ( QgsLayerTreeLayer* layer, layers )
+  {
+    QDomElement layerelm = doc.createElement( "maplayer" );
+    layer->layer()->writeLayerXML( layerelm, doc, fileinfo.canonicalFilePath() );
+    layerselm.appendChild( layerelm );
+  }
+  qgiselm.appendChild( layerselm );
+
+  if ( file.open( QFile::WriteOnly | QFile::Truncate ) )
+  {
+    QTextStream qlayerstream( &file );
+    doc.save( qlayerstream, 2 );
+    return true;
+  }
+  else
+  {
+    errorMessage = file.errorString();
+    return false;
+  }
+}

src/core/qgslayerdefinition.h

@@ -0,0 +1,20 @@
+#ifndef QGSLAYERDEFINITION_H
+#define QGSLAYERDEFINITION_H
+
+#include "qgslayertreegroup.h"
+
+/**
+ * @brief The QgsLayerDefinition class holds generic methods for loading/exporting QLR files.
+ */
+class CORE_EXPORT QgsLayerDefinition
+{
+public:
+  /* Loads the QLR at path into QGIS.  New layers are added to rootGroup and the map layer registry*/
+  static bool loadLayerDefinition( const QString & path, QgsLayerTreeGroup* rootGroup, QString &errorMessage);
+  /* Loads the QLR from the XML document.  New layers are added to rootGroup and the map layer registry */
+  static bool loadLayerDefinition( QDomDocument doc, QgsLayerTreeGroup* rootGroup, QString &errorMessage);
+  /* Export the selected layer tree nodes to a QLR file */
+  static bool exportLayerDefinition( QString path, QList<QgsLayerTreeNode*> selectedTreeNodes, QString &errorMessage );
+};
+
+#endif // QGSLAYERDEFINITION_H

src/core/qgsmaplayer.cpp

@@ -617,15 +617,16 @@ bool QgsMapLayer::writeLayerXML( QDomElement& layerElement, QDomDocument& docume
 QDomDocument QgsMapLayer::asLayerDefinition( QList<QgsMapLayer *> layers, QString relativeBasePath )
 {
   QDomDocument doc( "qgis-layer-definition" );
+  QDomElement qgiselm = doc.createElement( "qlr" );
+  doc.appendChild( qgiselm );
   QDomElement layerselm = doc.createElement( "maplayers" );
   foreach ( QgsMapLayer* layer, layers )
   {
     QDomElement layerelm = doc.createElement( "maplayer" );
     layer->writeLayerXML( layerelm, doc, relativeBasePath );
-    layerelm.removeChild( layerelm.firstChildElement( "id" ) );
     layerselm.appendChild( layerelm );
   }
-  doc.appendChild( layerselm );
+  qgiselm.appendChild( layerselm );
   return doc;
 }