[composer] Disable atlas if coverage layer is removed from project

Author: nyalldawson

src/core/composer/qgsatlascomposition.cpp

@@ -47,6 +47,9 @@ QgsAtlasComposition::QgsAtlasComposition( QgsComposition* composition ) :
   QgsExpression::setSpecialColumn( "$atlasfeatureid", QVariant(( int )0 ) );
   QgsExpression::setSpecialColumn( "$atlasfeature", QVariant::fromValue( QgsFeature() ) );
   QgsExpression::setSpecialColumn( "$atlasgeometry", QVariant::fromValue( QgsGeometry() ) );
+
+  //listen out for layer removal
+  connect( QgsMapLayerRegistry::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
 }
 
 QgsAtlasComposition::~QgsAtlasComposition()
@@ -55,13 +58,43 @@ QgsAtlasComposition::~QgsAtlasComposition()
 
 void QgsAtlasComposition::setEnabled( bool enabled )
 {
+  if ( enabled == mEnabled )
+  {
+    return;
+  }
+
   mEnabled = enabled;
   mComposition->setAtlasMode( QgsComposition::AtlasOff );
   emit toggled( enabled );
+  emit parameterChanged();
+}
+
+void QgsAtlasComposition::removeLayers( QStringList layers )
+{
+  if ( !mCoverageLayer )
+  {
+    return;
+  }
+
+  foreach ( QString layerId, layers )
+  {
+    if ( layerId == mCoverageLayer->id() )
+    {
+      //current coverage layer removed
+      mCoverageLayer = 0;
+      setEnabled( false );
+      return;
+    }
+  }
 }
 
 void QgsAtlasComposition::setCoverageLayer( QgsVectorLayer* layer )
 {
+  if ( layer == mCoverageLayer )
+  {
+    return;
+  }
+
   mCoverageLayer = layer;
 
   // update the number of features

src/core/composer/qgsatlascomposition.h

@@ -23,6 +23,7 @@
 #include <QString>
 #include <QDomElement>
 #include <QDomDocument>
+#include <QStringList>
 
 class QgsComposerMap;
 class QgsComposition;
@@ -305,6 +306,9 @@ class CORE_EXPORT QgsAtlasComposition : public QObject
   public:
     typedef QMap< QgsFeatureId, QVariant > SorterKeys;
 
+  private slots:
+    void removeLayers( QStringList layers );
+
   private:
     // value of field that is used for ordering of features
     SorterKeys mFeatureKeys;

tests/src/core/testqgsatlascomposition.cpp

@@ -63,6 +63,8 @@ class TestQgsAtlasComposition: public QObject
     void filtering_render();
     // test render signals
     void test_signals();
+    // test removing coverage layer while atlas is enabled
+    void test_remove_layer();
 
   private:
     QgsComposition* mComposition;
@@ -73,6 +75,7 @@ class TestQgsAtlasComposition: public QObject
     //QgsMapRenderer* mMapRenderer;
     QgsMapSettings mMapSettings;
     QgsVectorLayer* mVectorLayer;
+    QgsVectorLayer* mVectorLayer2;
     QgsAtlasComposition* mAtlas;
     QString mReport;
 };
@@ -87,6 +90,9 @@ void TestQgsAtlasComposition::initTestCase()
   mVectorLayer = new QgsVectorLayer( vectorFileInfo.filePath(),
                                      vectorFileInfo.completeBaseName(),
                                      "ogr" );
+  mVectorLayer2 = new QgsVectorLayer( vectorFileInfo.filePath(),
+                                      vectorFileInfo.completeBaseName(),
+                                      "ogr" );
 
   QgsVectorSimplifyMethod simplifyMethod;
   simplifyMethod.setSimplifyHints( QgsVectorSimplifyMethod::NoSimplification );
@@ -441,5 +447,24 @@ void TestQgsAtlasComposition::test_signals()
   QVERIFY( spyRenderEnded.count() == 1 );
 }
 
+void TestQgsAtlasComposition::test_remove_layer()
+{
+  mAtlas->setCoverageLayer( mVectorLayer2 );
+  mAtlas->setEnabled( true );
+
+  QSignalSpy spyToggled( mAtlas, SIGNAL( toggled( bool ) ) );
+
+  //remove coverage layer while atlas is enabled
+  QgsMapLayerRegistry::instance()->removeMapLayer( mVectorLayer2->id() );
+  mVectorLayer2 = 0;
+
+  QVERIFY( !mAtlas->enabled() );
+  QVERIFY( spyToggled.count() == 1 );
+
+  //clean up
+  mAtlas->setCoverageLayer( mVectorLayer );
+  mAtlas->setEnabled( true );
+}
+
 QTEST_MAIN( TestQgsAtlasComposition )
 #include "moc_testqgsatlascomposition.cxx"