Optimise some loops over QMap/QHash objects

Avoid iterating over keys() and then later retrieving the matching
values, and instead use QMap/QHash iterators to retrieve both the
keys and values at the same time

src/core/composer/qgscomposertablev2.cpp

@@ -137,11 +137,12 @@ bool QgsComposerTableV2::writeXML( QDomElement& elem, QDomDocument & doc, bool i
 
   //cell styles
   QDomElement stylesElem = doc.createElement( "cellStyles" );
-  Q_FOREACH ( CellStyleGroup group, mCellStyleNames.keys() )
+  QMap< CellStyleGroup, QString >::const_iterator it = mCellStyleNames.constBegin();
+  for ( ; it != mCellStyleNames.constEnd(); ++it )
   {
-    QString styleName = mCellStyleNames.value( group );
+    QString styleName = it.value();
     QDomElement styleElem = doc.createElement( styleName );
-    mCellStyles.value( group )->writeXML( styleElem, doc );
+    mCellStyles.value( it.key() )->writeXML( styleElem, doc );
     stylesElem.appendChild( styleElem );
   }
   elem.appendChild( stylesElem );
@@ -209,14 +210,16 @@ bool QgsComposerTableV2::readXML( const QDomElement &itemElem, const QDomDocumen
   if ( !stylesList.isEmpty() )
   {
     QDomElement stylesElem = stylesList.at( 0 ).toElement();
-    Q_FOREACH ( CellStyleGroup group, mCellStyleNames.keys() )
+
+    QMap< CellStyleGroup, QString >::const_iterator it = mCellStyleNames.constBegin();
+    for ( ; it != mCellStyleNames.constEnd(); ++it )
     {
-      QString styleName  = mCellStyleNames.value( group );
+      QString styleName = it.value();
       QDomNodeList styleList = stylesElem.elementsByTagName( styleName );
       if ( !styleList.isEmpty() )
       {
         QDomElement styleElem = styleList.at( 0 ).toElement();
-        mCellStyles.value( group )->readXML( styleElem );
+        mCellStyles.value( it.key() )->readXML( styleElem );
       }
     }
   }

src/core/effects/qgspainteffectregistry.cpp

@@ -53,11 +53,7 @@ QgsPaintEffectRegistry::QgsPaintEffectRegistry()
 
 QgsPaintEffectRegistry::~QgsPaintEffectRegistry()
 {
-  Q_FOREACH ( const QString& name, mMetadata.keys() )
-  {
-    delete mMetadata[name];
-  }
-  mMetadata.clear();
+  qDeleteAll( mMetadata );
 }
 
 QgsPaintEffectRegistry* QgsPaintEffectRegistry::instance()

src/core/geometry/qgswkbtypes.cpp

@@ -32,12 +32,14 @@ QMap<QgsWKBTypes::Type, QgsWKBTypes::wkbEntry>* QgsWKBTypes::entries()
 QgsWKBTypes::Type QgsWKBTypes::parseType( const QString &wktStr )
 {
   QString typestr = wktStr.left( wktStr.indexOf( '(' ) ).simplified().remove( ' ' );
-  Q_FOREACH ( Type type, entries()->keys() )
+
+  QMap<QgsWKBTypes::Type, QgsWKBTypes::wkbEntry>* knownTypes = entries();
+  QMap<QgsWKBTypes::Type, QgsWKBTypes::wkbEntry>::const_iterator it = knownTypes->constBegin();
+  for ( ; it != knownTypes->constEnd(); ++it )
   {
-    QMap< Type, wkbEntry >::const_iterator it = entries()->constFind( type );
-    if ( it != entries()->constEnd() && it.value().mName.compare( typestr, Qt::CaseInsensitive ) == 0 )
+    if ( it.value().mName.compare( typestr, Qt::CaseInsensitive ) == 0 )
     {
-      return type;
+      return it.key();
     }
   }
   return Unknown;

src/core/layertree/qgslayertreemodel.cpp

@@ -1345,8 +1345,10 @@ QList<QgsLayerTreeModelLegendNode*> QgsLayerTreeModel::layerOriginalLegendNodes(
 
 QgsLayerTreeModelLegendNode* QgsLayerTreeModel::findLegendNode( const QString& layerId, const QString& ruleKey ) const
 {
-  Q_FOREACH ( QgsLayerTreeLayer* layer, mLegend.keys() )
+  QMap<QgsLayerTreeLayer*, LayerLegendData>::const_iterator it = mLegend.constBegin();
+  for ( ; it != mLegend.constEnd(); ++it )
   {
+    QgsLayerTreeLayer* layer = it.key();
     if ( layer->layerId() == layerId )
     {
       Q_FOREACH ( QgsLayerTreeModelLegendNode* legendNode, mLegend.value( layer ).activeNodes )

src/core/pal/pal.cpp

@@ -271,7 +271,7 @@ Problem* Pal::extract( double lambda_min, double phi_min, double lambda_max, dou
   QStringList layersWithFeaturesInBBox;
 
   mMutex.lock();
-  Q_FOREACH ( Layer* layer, mLayers.values() )
+  Q_FOREACH ( Layer* layer, mLayers )
   {
     if ( !layer )
     {

src/core/qgsconditionalstyle.cpp

@@ -60,11 +60,12 @@ bool QgsConditionalLayerStyles::writeXml( QDomNode &node, QDomDocument &doc ) co
   stylesel.appendChild( rowel );
 
   QDomElement fieldsel = doc.createElement( "fieldstyles" );
-  Q_FOREACH ( const QString field, mFieldStyles.keys() )
+  QHash<QString, QgsConditionalStyles>::const_iterator it = mFieldStyles.constBegin();
+  for ( ; it != mFieldStyles.constEnd(); ++it )
   {
     QDomElement fieldel = doc.createElement( "fieldstyle" );
-    fieldel.setAttribute( "fieldname", field );
-    QgsConditionalStyles styles = mFieldStyles[field];
+    fieldel.setAttribute( "fieldname", it.key() );
+    QgsConditionalStyles styles = it.value();
     Q_FOREACH ( const QgsConditionalStyle& style, styles )
     {
       style.writeXml( fieldel, doc );

src/core/qgscoordinatereferencesystem.cpp

@@ -1838,9 +1838,10 @@ int QgsCoordinateReferenceSystem::syncDb()
 
   sql = "DELETE FROM tbl_srs WHERE auth_name='EPSG' AND NOT auth_id IN (";
   QString delim;
-  Q_FOREACH ( int i, wkts.keys() )
+  QHash<int, QString>::const_iterator it = wkts.constBegin();
+  for ( ; it != wkts.constEnd(); ++it )
   {
-    sql += delim + QString::number( i );
+    sql += delim + QString::number( it.key() );
     delim = ',';
   }
   sql += ") AND NOT noupdate";

src/core/qgsexpression.cpp

@@ -96,9 +96,11 @@ QgsExpression::Interval QgsExpression::Interval::fromString( const QString& stri
     }
 
     bool matched = false;
-    Q_FOREACH ( int duration, map.keys() )
+    QMap<int, QStringList>::const_iterator it = map.constBegin();
+    for ( ; it != map.constEnd(); ++it )
     {
-      Q_FOREACH ( const QString& name, map[duration] )
+      int duration = it.key();
+      Q_FOREACH ( const QString& name, it.value() )
       {
         if ( match.contains( name, Qt::CaseInsensitive ) )
         {

src/core/qgsexpressioncontext.cpp

@@ -52,9 +52,10 @@ QgsExpressionContextScope::QgsExpressionContextScope( const QgsExpressionContext
     : mName( other.mName )
     , mVariables( other.mVariables )
 {
-  Q_FOREACH ( const QString& key, other.mFunctions.keys() )
+  QHash<QString, QgsScopedExpressionFunction* >::const_iterator it = other.mFunctions.constBegin();
+  for ( ; it != other.mFunctions.constEnd(); ++it )
   {
-    mFunctions.insert( key, other.mFunctions.value( key )->clone() );
+    mFunctions.insert( it.key(), it.value()->clone() );
   }
 }
 
@@ -65,9 +66,10 @@ QgsExpressionContextScope& QgsExpressionContextScope::operator=( const QgsExpres
 
   qDeleteAll( mFunctions );
   mFunctions.clear();
-  Q_FOREACH ( const QString& key, other.mFunctions.keys() )
+  QHash<QString, QgsScopedExpressionFunction* >::const_iterator it = other.mFunctions.constBegin();
+  for ( ; it != other.mFunctions.constEnd(); ++it )
   {
-    mFunctions.insert( key, other.mFunctions.value( key )->clone() );
+    mFunctions.insert( it.key(), it.value()->clone() );
   }
 
   return *this;
@@ -503,10 +505,11 @@ void QgsExpressionContextUtils::setGlobalVariables( const QgsStringMap &variable
   QList< QVariant > customVariableVariants;
   QList< QVariant > customVariableNames;
 
-  Q_FOREACH ( const QString& variable, variables.keys() )
+  QMap< QString, QString >::const_iterator it = variables.constBegin();
+  for ( ; it != variables.constEnd(); ++it )
   {
-    customVariableNames << variable;
-    customVariableVariants << variables.value( variable );
+    customVariableNames << it.key();
+    customVariableVariants << it.value();
   }
 
   settings.setValue( QString( "/variables/names" ), customVariableNames );
@@ -622,10 +625,11 @@ void QgsExpressionContextUtils::setProjectVariables( const QgsStringMap &variabl
   QStringList variableNames;
   QStringList variableValues;
 
-  Q_FOREACH ( const QString& variable, variables.keys() )
+  QMap< QString, QString >::const_iterator it = variables.constBegin();
+  for ( ; it != variables.constEnd(); ++it )
   {
-    variableNames << variable;
-    variableValues << variables.value( variable );
+    variableNames << it.key();
+    variableValues << it.value();
   }
 
   project->writeEntry( "Variables", "/variableNames", variableNames );
@@ -696,10 +700,11 @@ void QgsExpressionContextUtils::setLayerVariables( QgsMapLayer* layer, const Qgs
   QStringList variableNames;
   QStringList variableValues;
 
-  Q_FOREACH ( const QString& variable, variables.keys() )
+  QMap< QString, QString >::const_iterator it = variables.constBegin();
+  for ( ; it != variables.constEnd(); ++it )
   {
-    variableNames << variable;
-    variableValues << variables.value( variable );
+    variableNames << it.key();
+    variableValues << it.value();
   }
 
   layer->setCustomProperty( "variableNames", variableNames );
@@ -797,10 +802,11 @@ void QgsExpressionContextUtils::setCompositionVariables( QgsComposition* composi
   QStringList variableNames;
   QStringList variableValues;
 
-  Q_FOREACH ( const QString& variable, variables.keys() )
+  QMap< QString, QString >::const_iterator it = variables.constBegin();
+  for ( ; it != variables.constEnd(); ++it )
   {
-    variableNames << variable;
-    variableValues << variables.value( variable );
+    variableNames << it.key();
+    variableValues << it.value();
   }
 
   composition->setCustomProperty( "variableNames", variableNames );
@@ -899,10 +905,11 @@ void QgsExpressionContextUtils::setComposerItemVariables( QgsComposerItem* compo
   QStringList variableNames;
   QStringList variableValues;
 
-  Q_FOREACH ( const QString& variable, variables.keys() )
+  QMap< QString, QString >::const_iterator it = variables.constBegin();
+  for ( ; it != variables.constEnd(); ++it )
   {
-    variableNames << variable;
-    variableValues << variables.value( variable );
+    variableNames << it.key();
+    variableValues << it.value();
   }
 
   composerItem->setCustomProperty( "variableNames", variableNames );

src/core/qgslayerdefinition.cpp

@@ -237,9 +237,9 @@ void QgsLayerDefinition::DependencySorter::init( const QDomDocument& doc )
   }
 
   // check that all dependencies are present
-  Q_FOREACH ( const QString& id, dependencies.keys() )
+  Q_FOREACH ( const QVector< QString >& ids, dependencies )
   {
-    Q_FOREACH ( const QString& depId, dependencies[id] )
+    Q_FOREACH ( const QString& depId, ids )
     {
       if ( !dependencies.contains( depId ) )
       {

src/core/qgsmaprenderercache.cpp

@@ -35,9 +35,10 @@ void QgsMapRendererCache::clearInternal()
   mScale = 0;
 
   // make sure we are disconnected from all layers
-  Q_FOREACH ( const QString& layerId, mCachedImages.keys() )
+  QMap<QString, QImage>::const_iterator it = mCachedImages.constBegin();
+  for ( ; it != mCachedImages.constEnd(); ++it )
   {
-    QgsMapLayer* layer = QgsMapLayerRegistry::instance()->mapLayer( layerId );
+    QgsMapLayer* layer = QgsMapLayerRegistry::instance()->mapLayer( it.key() );
     if ( layer )
     {
       disconnect( layer, SIGNAL( repaintRequested() ), this, SLOT( layerRequestedRepaint() ) );

src/core/qgsmaprenderercustompainterjob.cpp

@@ -357,10 +357,11 @@ void QgsMapRendererJob::drawNewLabeling( const QgsMapSettings& settings, QgsRend
 
 void QgsMapRendererJob::updateLayerGeometryCaches()
 {
-  Q_FOREACH ( const QString& id, mGeometryCaches.keys() )
+  QMap<QString, QgsGeometryCache>::const_iterator it = mGeometryCaches.constBegin();
+  for ( ; it != mGeometryCaches.constEnd(); ++it )
   {
-    const QgsGeometryCache& cache = mGeometryCaches[id];
-    if ( QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( id ) ) )
+    const QgsGeometryCache& cache = it.value();
+    if ( QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( it.key() ) ) )
       * vl->cache() = cache;
   }
   mGeometryCaches.clear();

src/core/qgspluginlayerregistry.cpp

@@ -75,8 +75,11 @@ QgsPluginLayerRegistry::~QgsPluginLayerRegistry()
   if ( !mPluginLayerTypes.isEmpty() )
   {
     QgsDebugMsg( "QgsPluginLayerRegistry::~QgsPluginLayerRegistry(): creator list not empty" );
-    Q_FOREACH ( const QString& typeName, mPluginLayerTypes.keys() )
-      removePluginLayerType( typeName );
+    PluginLayerTypes::const_iterator it = mPluginLayerTypes.constBegin();
+    for ( ; it != mPluginLayerTypes.constEnd(); ++it )
+    {
+      removePluginLayerType( it.key() );
+    }
   }
 }
 

src/core/qgsrulebasedlabeling.cpp

@@ -31,7 +31,7 @@ QgsRuleBasedLabelProvider::~QgsRuleBasedLabelProvider()
 
 bool QgsRuleBasedLabelProvider::prepare( const QgsRenderContext& context, QStringList& attributeNames )
 {
-  Q_FOREACH ( QgsVectorLayerLabelProvider* provider, mSubProviders.values() )
+  Q_FOREACH ( QgsVectorLayerLabelProvider* provider, mSubProviders )
     provider->setEngine( mEngine );
 
   // populate sub-providers
@@ -48,7 +48,7 @@ void QgsRuleBasedLabelProvider::registerFeature( QgsFeature& feature, QgsRenderC
 QList<QgsAbstractLabelProvider*> QgsRuleBasedLabelProvider::subProviders()
 {
   QList<QgsAbstractLabelProvider*> lst;
-  Q_FOREACH ( QgsVectorLayerLabelProvider* subprovider, mSubProviders.values() )
+  Q_FOREACH ( QgsVectorLayerLabelProvider* subprovider, mSubProviders )
     lst << subprovider;
   return lst;
 }

src/core/qgsvectorlayereditbuffer.cpp

@@ -607,9 +607,10 @@ QString QgsVectorLayerEditBuffer::dumpEditBuffer()
 void QgsVectorLayerEditBuffer::handleAttributeAdded( int index )
 {
   // go through the changed attributes map and adapt indices
-  Q_FOREACH ( QgsFeatureId fid, mChangedAttributeValues.keys() )
+  QgsChangedAttributesMap::iterator it = mChangedAttributeValues.begin();
+  for ( ; it != mChangedAttributeValues.end(); ++it )
   {
-    updateAttributeMapIndex( mChangedAttributeValues[fid], index, + 1 );
+    updateAttributeMapIndex( it.value(), index, + 1 );
   }
 
   // go through added features and adapt attributes
@@ -625,9 +626,10 @@ void QgsVectorLayerEditBuffer::handleAttributeAdded( int index )
 void QgsVectorLayerEditBuffer::handleAttributeDeleted( int index )
 {
   // go through the changed attributes map and adapt indices
-  Q_FOREACH ( QgsFeatureId fid, mChangedAttributeValues.keys() )
+  QgsChangedAttributesMap::iterator it = mChangedAttributeValues.begin();
+  for ( ; it != mChangedAttributeValues.end(); ++it )
   {
-    QgsAttributeMap& attrMap = mChangedAttributeValues[fid];
+    QgsAttributeMap& attrMap = it.value();
     // remove the attribute
     if ( attrMap.contains( index ) )
       attrMap.remove( index );

src/core/qgsvectorlayerimport.cpp

@@ -87,7 +87,7 @@ QgsVectorLayerImport::QgsVectorLayerImport( const QString &uri,
     return;
   }
 
-  Q_FOREACH ( int idx, mOldToNewAttrIdx.values() )
+  Q_FOREACH ( int idx, mOldToNewAttrIdx )
   {
     if ( idx > mAttributeCount )
       mAttributeCount = idx;