More const correctness and pass-by-ref

Author: Sandro Santilli

src/providers/postgres/qgspgtablemodel.cpp

@@ -42,7 +42,7 @@ QgsPgTableModel::~QgsPgTableModel()
 {
 }
 
-void QgsPgTableModel::addTableEntry( QgsPostgresLayerProperty layerProperty )
+void QgsPgTableModel::addTableEntry( const QgsPostgresLayerProperty& layerProperty )
 {
   QgsDebugMsg( layerProperty.toString() );
 
@@ -272,7 +272,7 @@ bool QgsPgTableModel::setData( const QModelIndex &idx, const QVariant &value, in
   return true;
 }
 
-QString QgsPgTableModel::layerURI( const QModelIndex &index, QString connInfo, bool useEstimatedMetadata )
+QString QgsPgTableModel::layerURI( const QModelIndex &index, const QString& connInfo, bool useEstimatedMetadata )
 {
   if ( !index.isValid() )
   {

src/providers/postgres/qgspgtablemodel.h

@@ -34,7 +34,7 @@ class QgsPgTableModel : public QStandardItemModel
     ~QgsPgTableModel();
 
     /**Adds entry for one database table to the model*/
-    void addTableEntry( QgsPostgresLayerProperty property );
+    void addTableEntry( const QgsPostgresLayerProperty& property );
 
     /**Sets an sql statement that belongs to a cell specified by a model index*/
     void setSql( const QModelIndex& index, const QString& sql );
@@ -58,7 +58,7 @@ class QgsPgTableModel : public QStandardItemModel
 
     bool setData( const QModelIndex &index, const QVariant &value, int role = Qt::EditRole );
 
-    QString layerURI( const QModelIndex &index, QString connInfo, bool useEstimatedMetadata );
+    QString layerURI( const QModelIndex &index, const QString& connInfo, bool useEstimatedMetadata );
 
     static QIcon iconForWkbType( QGis::WkbType type );
 

src/providers/postgres/qgspostgresconn.h

@@ -55,9 +55,9 @@ struct QgsPostgresLayerProperty
   QList<int>                    srids;
   QString                       sql;
 
-  int size() { Q_ASSERT( types.size() == srids.size() ); return types.size(); }
+  int size() const { Q_ASSERT( types.size() == srids.size() ); return types.size(); }
 
-  QgsPostgresLayerProperty at( int i )
+  QgsPostgresLayerProperty at( int i ) const
   {
     QgsPostgresLayerProperty property;
 
@@ -76,7 +76,7 @@ struct QgsPostgresLayerProperty
   }
 
 #if QGISDEBUG
-  QString toString()
+  QString toString() const
   {
     QString typeString;
     foreach ( QGis::WkbType type, types )