Make composition associated with QgsProject (#3957)

... rather than using project singleton within compositions

Author: wonder-sk

doc/api_break.dox

@@ -615,6 +615,7 @@ QgsComposerTableV2        {#qgis_api_break_3_0_QgsComposerTableV2}
 QgsComposition        {#qgis_api_break_3_0_QgsComposition}
 --------------
 
+- constructor requires QgsProject instance as the second argument
 - addItemsFromXML() has been renamed to addItemsFromXml()
 - Constructor with QgsMapRenderer parameter has been removed. Use the variant with QgsMapSettings parameter.
 - mapRenderer() has been removed. Use mapSettings() instead.

python/core/composer/qgscomposition.sip

@@ -40,7 +40,7 @@ class QgsComposition : QGraphicsScene, QgsExpressionContextGenerator
       Landscape
     };
 
-    explicit QgsComposition( const QgsMapSettings& mapSettings );
+    explicit QgsComposition( const QgsMapSettings& mapSettings, QgsProject* project );
 
     /** Composition atlas modes*/
     enum AtlasMode
@@ -52,6 +52,14 @@ class QgsComposition : QGraphicsScene, QgsExpressionContextGenerator
 
     ~QgsComposition();
 
+    /**
+     * The project associated with the composition. Used to get access to layers, map themes,
+     * relations and various other bits. It is never null.
+     *
+     * \note Added in QGIS 3.0
+     */
+    QgsProject* project() const;
+
     /** Changes size of paper item.
      * @param width page width in mm
      * @param height page height in mm

src/app/composer/qgscomposer.cpp

@@ -547,7 +547,7 @@ QgsComposer::QgsComposer( QgisApp *qgis, const QString& title )
   connect( mActionShowRulers, SIGNAL( triggered( bool ) ), this, SLOT( toggleRulers( bool ) ) );
 
   //init undo/redo buttons
-  mComposition = new QgsComposition( mQgis->mapCanvas()->mapSettings() );
+  mComposition = new QgsComposition( mQgis->mapCanvas()->mapSettings(), QgsProject::instance() );
 
   mActionUndo->setEnabled( false );
   mActionRedo->setEnabled( false );
@@ -3543,7 +3543,7 @@ void QgsComposer::readXml( const QDomElement& composerElem, const QDomDocument&
   createComposerView();
 
   //read composition settings
-  mComposition = new QgsComposition( mQgis->mapCanvas()->mapSettings() );
+  mComposition = new QgsComposition( mQgis->mapCanvas()->mapSettings(), QgsProject::instance() );
   QDomNodeList compositionNodeList = composerElem.elementsByTagName( QStringLiteral( "Composition" ) );
   if ( compositionNodeList.size() > 0 )
   {

src/core/composer/qgsaddremoveitemcommand.cpp

@@ -80,5 +80,5 @@ void QgsAddRemoveItemCommand::switchState()
     emit itemAdded( mItem );
     mState = Added;
   }
-  QgsProject::instance()->setDirty( true );
+  mComposition->project()->setDirty( true );
 }

src/core/composer/qgsaddremovemultiframecommand.cpp

@@ -78,7 +78,7 @@ void QgsAddRemoveMultiFrameCommand::switchState()
       mComposition->addMultiFrame( mMultiFrame );
       mState = Added;
     }
-    QgsProject::instance()->setDirty( true );
+    mComposition->project()->setDirty( true );
   }
 }
 

src/core/composer/qgsatlascomposition.cpp

@@ -45,7 +45,7 @@ QgsAtlasComposition::QgsAtlasComposition( QgsComposition* composition )
 {
 
   //listen out for layer removal
-  connect( QgsProject::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
+  connect( mComposition->project(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
 }
 
 void QgsAtlasComposition::setEnabled( bool enabled )
@@ -625,7 +625,7 @@ void QgsAtlasComposition::readXml( const QDomElement& atlasElem, const QDomDocum
 
   // look for stored layer name
   QString coverageLayerId = atlasElem.attribute( QStringLiteral( "coverageLayer" ) );
-  mCoverageLayer = qobject_cast<QgsVectorLayer*>( QgsProject::instance()->mapLayer( coverageLayerId ) );
+  mCoverageLayer = qobject_cast<QgsVectorLayer*>( mComposition->project()->mapLayer( coverageLayerId ) );
 
   mPageNameExpression = atlasElem.attribute( QStringLiteral( "pageNameExpression" ), QString() );
   mSingleFile = atlasElem.attribute( QStringLiteral( "singleFile" ), QStringLiteral( "false" ) ) == QLatin1String( "true" ) ? true : false;
@@ -718,7 +718,7 @@ QgsExpressionContext QgsAtlasComposition::createExpressionContext()
 {
   QgsExpressionContext expressionContext;
   expressionContext << QgsExpressionContextUtils::globalScope()
-  << QgsExpressionContextUtils::projectScope( QgsProject::instance() );
+  << QgsExpressionContextUtils::projectScope( mComposition->project() );
   if ( mComposition )
     expressionContext << QgsExpressionContextUtils::compositionScope( mComposition );
 

src/core/composer/qgscomposerattributetablev2.cpp

@@ -62,7 +62,7 @@ QgsComposerAttributeTableV2::QgsComposerAttributeTableV2( QgsComposition* compos
     , mFeatureFilter( QLatin1String( "" ) )
 {
   //set first vector layer from layer registry as default one
-  QMap<QString, QgsMapLayer*> layerMap =  QgsProject::instance()->mapLayers();
+  QMap<QString, QgsMapLayer*> layerMap =  mComposition->project()->mapLayers();
   QMap<QString, QgsMapLayer*>::const_iterator mapIt = layerMap.constBegin();
   for ( ; mapIt != layerMap.constEnd(); ++mapIt )
   {
@@ -79,10 +79,11 @@ QgsComposerAttributeTableV2::QgsComposerAttributeTableV2( QgsComposition* compos
     //listen for modifications to layer and refresh table when they occur
     connect( mVectorLayer, SIGNAL( layerModified() ), this, SLOT( refreshAttributes() ) );
   }
-  connect( QgsProject::instance(), SIGNAL( layerWillBeRemoved( QString ) ), this, SLOT( removeLayer( const QString& ) ) );
 
   if ( mComposition )
   {
+    connect( mComposition->project(), SIGNAL( layerWillBeRemoved( QString ) ), this, SLOT( removeLayer( const QString& ) ) );
+
     //refresh table attributes when composition is refreshed
     connect( mComposition, SIGNAL( refreshItemsTriggered() ), this, SLOT( refreshAttributes() ) );
 
@@ -140,7 +141,7 @@ void QgsComposerAttributeTableV2::setRelationId( const QString& relationId )
 
   QgsVectorLayer* prevLayer = sourceLayer();
   mRelationId = relationId;
-  QgsRelation relation = QgsProject::instance()->relationManager()->relation( mRelationId );
+  QgsRelation relation = mComposition->project()->relationManager()->relation( mRelationId );
   QgsVectorLayer* newLayer = relation.referencingLayer();
 
   if ( mSource == QgsComposerAttributeTableV2::RelationChildren && newLayer != prevLayer )
@@ -438,7 +439,7 @@ bool QgsComposerAttributeTableV2::getTableContents( QgsComposerTableContents &co
 
   if ( mSource == QgsComposerAttributeTableV2::RelationChildren )
   {
-    QgsRelation relation = QgsProject::instance()->relationManager()->relation( mRelationId );
+    QgsRelation relation = mComposition->project()->relationManager()->relation( mRelationId );
     QgsFeature atlasFeature = mComposition->atlasComposition().feature();
     req = relation.getRelatedFeaturesRequest( atlasFeature );
   }
@@ -564,7 +565,7 @@ QgsVectorLayer *QgsComposerAttributeTableV2::sourceLayer()
       return mVectorLayer;
     case QgsComposerAttributeTableV2::RelationChildren:
     {
-      QgsRelation relation = QgsProject::instance()->relationManager()->relation( mRelationId );
+      QgsRelation relation = mComposition->project()->relationManager()->relation( mRelationId );
       return relation.referencingLayer();
     }
   }
@@ -731,7 +732,7 @@ bool QgsComposerAttributeTableV2::readXml( const QDomElement& itemElem, const QD
   }
   else
   {
-    QgsMapLayer* ml = QgsProject::instance()->mapLayer( layerId );
+    QgsMapLayer* ml = mComposition->project()->mapLayer( layerId );
     if ( ml )
     {
       mVectorLayer = dynamic_cast<QgsVectorLayer*>( ml );

src/core/composer/qgscomposerhtml.cpp

@@ -185,7 +185,7 @@ void QgsComposerHtml::loadHtml( const bool useCache, const QgsExpressionContext
   //set html, using the specified url as base if in Url mode or the project file if in manual mode
   const QUrl baseUrl = mContentMode == QgsComposerHtml::Url ?
                        QUrl( mActualFetchedUrl ) :
-                       QUrl::fromLocalFile( QgsProject::instance()->fileInfo().absoluteFilePath() );
+                       QUrl::fromLocalFile( mComposition->project()->fileInfo().absoluteFilePath() );
   mWebPage->mainFrame()->setHtml( loadedHtml, baseUrl );
 
   //set user stylesheet
@@ -547,8 +547,8 @@ void QgsComposerHtml::setExpressionContext( const QgsFeature &feature, QgsVector
   if ( mComposition )
   {
     mDistanceArea->setEllipsoidalMode( mComposition->mapSettings().hasCrsTransformEnabled() );
+    mDistanceArea->setEllipsoid( mComposition->project()->ellipsoid() );
   }
-  mDistanceArea->setEllipsoid( QgsProject::instance()->ellipsoid() );
 
   // create JSON representation of feature
   QgsJSONExporter exporter( layer );

src/core/composer/qgscomposeritemcommand.cpp

@@ -19,6 +19,7 @@
 #include "qgscomposeritem.h"
 #include "qgscomposerframe.h"
 #include "qgscomposermultiframe.h"
+#include "qgscomposition.h"
 #include "qgsproject.h"
 #include "qgslogger.h"
 
@@ -114,7 +115,7 @@ void QgsComposerItemCommand::restoreState( QDomDocument& stateDoc ) const
 
   destItem->readXml( stateDoc.documentElement().firstChild().toElement(), stateDoc );
   destItem->repaint();
-  QgsProject::instance()->setDirty( true );
+  destItem->composition()->project()->setDirty( true );
 }
 
 //

src/core/composer/qgscomposerlabel.cpp

@@ -165,7 +165,7 @@ void QgsComposerLabel::contentChanged()
     //set this to true after html is loaded.
     mHtmlLoaded = false;
 
-    const QUrl baseUrl = QUrl::fromLocalFile( QgsProject::instance()->fileInfo().absoluteFilePath() );
+    const QUrl baseUrl = QUrl::fromLocalFile( mComposition->project()->fileInfo().absoluteFilePath() );
     mWebPage->mainFrame()->setHtml( textToDraw, baseUrl );
 
     //For very basic html labels with no external assets, the html load will already be
@@ -265,7 +265,7 @@ void QgsComposerLabel::refreshExpressionContext()
     mDistanceArea->setSourceCrs( mComposition->mapSettings().destinationCrs().srsid() );
   }
   mDistanceArea->setEllipsoidalMode( mComposition->mapSettings().hasCrsTransformEnabled() );
-  mDistanceArea->setEllipsoid( QgsProject::instance()->ellipsoid() );
+  mDistanceArea->setEllipsoid( mComposition->project()->ellipsoid() );
   contentChanged();
 
   update();