More efficient use of QStrings

- use .isEmpty() instead of == QLatin1String( "" ) to check for empty strings - use .clear() instead of = QLatin1String( "" ) to empty a string - remove unnecessary QString initializations
qgis · Sep 27, 2017 · 8c3939e · 8c3939e
1 parent 036646f
commit 8c3939e
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Showing 102 changed files with 282 additions and 305 deletions.
diff --git a/src/app/composer/qgscomposermapgridwidget.cpp b/src/app/composer/qgscomposermapgridwidget.cpp
@@ -438,7 +438,7 @@ bool QgsComposerMapGridWidget::hasPredefinedScales() const
     QgsSettings settings;
     QString scalesStr( settings.value( QStringLiteral( "Map/scales" ), PROJECT_SCALES ).toString() );
     QStringList myScalesList = scalesStr.split( ',' );
-    return !myScalesList.isEmpty() && myScalesList[0] != QLatin1String( "" );
+    return !myScalesList.isEmpty() && !myScalesList[0].isEmpty();
   }
   return true;
 }

diff --git a/src/app/composer/qgscomposermapwidget.cpp b/src/app/composer/qgscomposermapwidget.cpp
@@ -1051,7 +1051,7 @@ bool QgsComposerMapWidget::hasPredefinedScales() const
     QgsSettings settings;
     QString scalesStr( settings.value( QStringLiteral( "Map/scales" ), PROJECT_SCALES ).toString() );
     QStringList myScalesList = scalesStr.split( ',' );
-    return !myScalesList.isEmpty() && myScalesList[0] != QLatin1String( "" );
+    return !myScalesList.isEmpty() && !myScalesList[0].isEmpty();
   }
   return true;
 }

diff --git a/src/app/composer/qgscomposerpicturewidget.cpp b/src/app/composer/qgscomposerpicturewidget.cpp
@@ -564,7 +564,7 @@ int QgsComposerPictureWidget::addDirectoryToPreview( const QString &path )
       listItem->setIcon( icon );
     }
 
-    listItem->setText( QLatin1String( "" ) );
+    listItem->setText( QString() );
     //store the absolute icon file path as user data
     listItem->setData( Qt::UserRole, fileIt->absoluteFilePath() );
     ++counter;

diff --git a/src/app/main.cpp b/src/app/main.cpp
@@ -168,7 +168,7 @@ void usage( const QString &appName )
 // AppleEvent handler as well as by the main routine argv processing
 
 // This behavior will cause QGIS to autoload a project
-static QString sProjectFileName = QLatin1String( "" );
+static QString sProjectFileName;
 
 // This is the 'leftover' arguments collection
 static QStringList sFileList;
@@ -492,8 +492,8 @@ int main( int argc, char *argv[] )
 
   // This behavior is used to load the app, snapshot the map,
   // save the image to disk and then exit
-  QString mySnapshotFileName = QLatin1String( "" );
-  QString configLocalStorageLocation = QLatin1String( "" );
+  QString mySnapshotFileName;
+  QString configLocalStorageLocation;
   QString profileName;
   int mySnapshotWidth = 800;
   int mySnapshotHeight = 600;
@@ -520,7 +520,7 @@ int main( int argc, char *argv[] )
   // there are no command line arguments. This gives a usable map
   // extent when qgis starts with no layers loaded. When layers are
   // loaded, we let the layers define the initial extent.
-  QString myInitialExtent = QLatin1String( "" );
+  QString myInitialExtent;
   if ( argc == 1 )
     myInitialExtent = QStringLiteral( "-1,-1,1,1" );
 
@@ -1238,7 +1238,7 @@ int main( int argc, char *argv[] )
   /////////////////////////////////`////////////////////////////////////
   // Take a snapshot of the map view then exit if snapshot mode requested
   /////////////////////////////////////////////////////////////////////
-  if ( mySnapshotFileName != QLatin1String( "" ) )
+  if ( !mySnapshotFileName.isEmpty() )
   {
     /*You must have at least one paintEvent() delivered for the window to be
       rendered properly.

diff --git a/src/app/pluginmanager/qgspluginmanager.cpp b/src/app/pluginmanager/qgspluginmanager.cpp
@@ -622,20 +622,19 @@ void QgsPluginManager::showPluginDetails( QStandardItem *item )
     return;
   }
 
-  QString html = QLatin1String( "" );
-  html += "<style>"
-          "  body, table {"
-          "    padding:0px;"
-          "    margin:0px;"
-          "    font-family:verdana;"
-          "    font-size: 10pt;"
-          "  }"
-          "  div#votes {"
-          "    width:360px;"
-          "    margin-left:98px;"
-          "    padding-top:3px;"
-          "  }"
-          "</style>";
+  QString html = "<style>"
+                 "  body, table {"
+                 "    padding:0px;"
+                 "    margin:0px;"
+                 "    font-family:verdana;"
+                 "    font-size: 10pt;"
+                 "  }"
+                 "  div#votes {"
+                 "    width:360px;"
+                 "    margin-left:98px;"
+                 "    padding-top:3px;"
+                 "  }"
+                 "</style>";
 
   if ( !metadata->value( QStringLiteral( "plugin_id" ) ).isEmpty() )
   {
@@ -1135,7 +1134,7 @@ void QgsPluginManager::setCurrentTab( int idx )
     mModelProxy->setAcceptedStatuses( acceptedStatuses );
 
     // load tab description HTML to the detail browser
-    QString tabInfoHTML = QLatin1String( "" );
+    QString tabInfoHTML;
     QMap<QString, QString>::const_iterator it = mTabDescriptions.constFind( tabTitle );
     if ( it != mTabDescriptions.constEnd() )
     {

diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -5792,7 +5792,7 @@ void QgisApp::saveMapAsPdf()
 //overloaded version of the above function
 void QgisApp::saveMapAsImage( const QString &imageFileNameQString, QPixmap *theQPixmap )
 {
-  if ( imageFileNameQString == QLatin1String( "" ) )
+  if ( imageFileNameQString.isEmpty() )
   {
     //no fileName chosen
     return;
@@ -9913,7 +9913,7 @@ void QgisApp::setExtent( const QgsRectangle &rect )
  */
 bool QgisApp::saveDirty()
 {
-  QString whyDirty = QLatin1String( "" );
+  QString whyDirty;
   bool hasUnsavedEdits = false;
   // extra check to see if there are any vector layers with unsaved provider edits
   // to ensure user has opportunity to save any editing

diff --git a/src/app/qgsabout.cpp b/src/app/qgsabout.cpp
@@ -186,7 +186,7 @@ void QgsAbout::init()
 #endif
   if ( translatorFile.open( QIODevice::ReadOnly ) )
   {
-    QString translatorHTML = QLatin1String( "" );
+    QString translatorHTML;
     QTextStream translatorStream( &translatorFile );
     // Always use UTF-8
     translatorStream.setCodec( "UTF-8" );

diff --git a/src/app/qgscustomprojectiondialog.cpp b/src/app/qgscustomprojectiondialog.cpp
@@ -308,7 +308,7 @@ bool QgsCustomProjectionDialog::saveCrs( QgsCoordinateReferenceSystem myCRS, con
 void QgsCustomProjectionDialog::on_pbnAdd_clicked()
 {
   QString name = tr( "new CRS" );
-  QString id = QLatin1String( "" );
+  QString id;
   QgsCoordinateReferenceSystem parameters;
 
   QTreeWidgetItem *newItem = new QTreeWidgetItem( leNameList, QStringList() );
@@ -331,7 +331,7 @@ void QgsCustomProjectionDialog::on_pbnRemove_clicked()
   }
   QTreeWidgetItem *item = leNameList->takeTopLevelItem( i );
   delete item;
-  if ( customCRSids[i] != QLatin1String( "" ) )
+  if ( !customCRSids[i].isEmpty() )
   {
     deletedCRSs.push_back( customCRSids[i] );
   }
@@ -361,8 +361,8 @@ void QgsCustomProjectionDialog::on_leNameList_currentItemChanged( QTreeWidgetIte
   else
   {
     //Can happen that current is null, for example if we just deleted the last element
-    leName->setText( QLatin1String( "" ) );
-    teParameters->setPlainText( QLatin1String( "" ) );
+    leName->clear();
+    teParameters->clear();
     return;
   }
 }
@@ -415,7 +415,7 @@ void QgsCustomProjectionDialog::on_buttonBox_accepted()
   {
     CRS.createFromProj4( customCRSparameters[i] );
     //Test if we just added this CRS (if it has no existing ID)
-    if ( customCRSids[i] == QLatin1String( "" ) )
+    if ( !customCRSids[i].isEmpty() )
     {
       save_success &= saveCrs( CRS, customCRSnames[i], QLatin1String( "" ), true );
     }
@@ -462,8 +462,8 @@ void QgsCustomProjectionDialog::on_pbnCalculate_clicked()
   {
     QMessageBox::information( this, tr( "QGIS Custom Projection" ),
                               tr( "This proj4 projection definition is not valid." ) );
-    projectedX->setText( QLatin1String( "" ) );
-    projectedY->setText( QLatin1String( "" ) );
+    projectedX->clear();
+    projectedY->clear();
     pj_free( myProj );
     pj_ctx_free( pContext );
     return;
@@ -478,8 +478,8 @@ void QgsCustomProjectionDialog::on_pbnCalculate_clicked()
   {
     QMessageBox::information( this, tr( "QGIS Custom Projection" ),
                               tr( "Northing and Easthing must be in decimal form." ) );
-    projectedX->setText( QLatin1String( "" ) );
-    projectedY->setText( QLatin1String( "" ) );
+    projectedX->clear();
+    projectedY->clear();
     pj_free( myProj );
     pj_ctx_free( pContext );
     return;
@@ -491,8 +491,8 @@ void QgsCustomProjectionDialog::on_pbnCalculate_clicked()
   {
     QMessageBox::information( this, tr( "QGIS Custom Projection" ),
                               tr( "Internal Error (source projection invalid?)" ) );
-    projectedX->setText( QLatin1String( "" ) );
-    projectedY->setText( QLatin1String( "" ) );
+    projectedX->clear();
+    projectedY->clear();
     pj_free( wgs84Proj );
     pj_ctx_free( pContext );
     return;

diff --git a/src/app/qgsdecorationgrid.cpp b/src/app/qgsdecorationgrid.cpp
@@ -110,8 +110,8 @@ void QgsDecorationGrid::projectRead()
   mGridAnnotationPosition = InsideMapFrame; // don't allow outside frame, doesn't make sense
   mGridAnnotationDirection = static_cast< GridAnnotationDirection >( QgsProject::instance()->readNumEntry( mNameConfig,
                              QStringLiteral( "/AnnotationDirection" ), 0 ) );
-  QString fontStr = QgsProject::instance()->readEntry( mNameConfig, QStringLiteral( "/AnnotationFont" ), QLatin1String( "" ) );
-  if ( fontStr != QLatin1String( "" ) )
+  QString fontStr = QgsProject::instance()->readEntry( mNameConfig, QStringLiteral( "/AnnotationFont" ), QString() );
+  if ( !fontStr.isEmpty() )
   {
     mGridAnnotationFont.fromString( fontStr );
   }
@@ -134,7 +134,7 @@ void QgsDecorationGrid::projectRead()
   if ( mLineSymbol )
     setLineSymbol( nullptr );
   xml = QgsProject::instance()->readEntry( mNameConfig, QStringLiteral( "/LineSymbol" ) );
-  if ( xml != QLatin1String( "" ) )
+  if ( !xml.isEmpty() )
   {
     doc.setContent( xml );
     elem = doc.documentElement();
@@ -146,7 +146,7 @@ void QgsDecorationGrid::projectRead()
   if ( mMarkerSymbol )
     setMarkerSymbol( nullptr );
   xml = QgsProject::instance()->readEntry( mNameConfig, QStringLiteral( "/MarkerSymbol" ) );
-  if ( xml != QLatin1String( "" ) )
+  if ( !xml.isEmpty() )
   {
     doc.setContent( xml );
     elem = doc.documentElement();

diff --git a/src/app/qgsmapsavedialog.cpp b/src/app/qgsmapsavedialog.cpp
@@ -380,7 +380,7 @@ void QgsMapSaveDialog::onAccepted()
   if ( mDialogType == Image )
   {
     QPair< QString, QString> fileNameAndFilter = QgsGuiUtils::getSaveAsImageName( QgisApp::instance(), tr( "Choose a file name to save the map image as" ) );
-    if ( fileNameAndFilter.first != QLatin1String( "" ) )
+    if ( !fileNameAndFilter.first.isEmpty() )
     {
       QgsMapSettings ms = QgsMapSettings();
       applyMapSettings( ms );

diff --git a/src/app/qgsnewspatialitelayerdialog.cpp b/src/app/qgsnewspatialitelayerdialog.cpp
@@ -340,7 +340,7 @@ bool QgsNewSpatialiteLayerDialog::apply()
 {
   // Build up the sql statement for creating the table
   QString sql = QStringLiteral( "create table %1(" ).arg( quotedIdentifier( leLayerName->text() ) );
-  QString delim = QLatin1String( "" );
+  QString delim;
 
   if ( checkBoxPrimaryKey->isChecked() )
   {

diff --git a/src/app/qgsprojectproperties.cpp b/src/app/qgsprojectproperties.cpp
@@ -1867,8 +1867,8 @@ void QgsProjectProperties::updateEllipsoidUI( int newIndex )
   mEllipsoidIndex = newIndex;
   leSemiMajor->setEnabled( false );
   leSemiMinor->setEnabled( false );
-  leSemiMajor->setText( QLatin1String( "" ) );
-  leSemiMinor->setText( QLatin1String( "" ) );
+  leSemiMajor->clear();
+  leSemiMinor->clear();
 
   cmbEllipsoid->setEnabled( projectionSelector->crs().isValid() );
   cmbEllipsoid->setToolTip( QLatin1String( "" ) );

diff --git a/src/app/qgsrelationmanagerdialog.cpp b/src/app/qgsrelationmanagerdialog.cpp
@@ -88,7 +88,7 @@ void QgsRelationManagerDialog::on_mBtnAddRelation_clicked()
     relation.setReferencingLayer( addDlg.referencingLayerId() );
     relation.setReferencedLayer( addDlg.referencedLayerId() );
     QString relationId = addDlg.relationId();
-    if ( addDlg.relationId() == QLatin1String( "" ) )
+    if ( addDlg.relationId().isEmpty() )
       relationId = QStringLiteral( "%1_%2_%3_%4" )
                    .arg( addDlg.referencingLayerId(),
                          addDlg.references().at( 0 ).first,

diff --git a/src/app/qgsversioninfo.cpp b/src/app/qgsversioninfo.cpp
@@ -79,7 +79,7 @@ void QgsVersionInfo::versionReplyFinished()
       mErrorString = tr( "The host name %1 could not be resolved. Check your DNS settings or contact your system administrator." ).arg( reply->request().url().host() );
       break;
     case QNetworkReply::NoError:
-      mErrorString = QLatin1String( "" );
+      mErrorString.clear();
       break;
     default:
       mErrorString = reply->errorString();

diff --git a/src/app/qgswelcomepageitemsmodel.cpp b/src/app/qgswelcomepageitemsmodel.cpp
@@ -150,7 +150,7 @@ QVariant QgsWelcomePageItemsModel::data( const QModelIndex &index, int role ) co
     case PathRole:
       return QDir::toNativeSeparators( mRecentProjects.at( index.row() ).path );
     case CrsRole:
-      if ( mRecentProjects.at( index.row() ).crs != QLatin1String( "" ) )
+      if ( !mRecentProjects.at( index.row() ).crs.isEmpty() )
       {
         QgsCoordinateReferenceSystem crs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( mRecentProjects.at( index.row() ).crs );
         return  QStringLiteral( "%1 (%2)" ).arg( mRecentProjects.at( index.row() ).crs, crs.description() );

diff --git a/src/auth/pkipaths/qgsauthpkipathsedit.cpp b/src/auth/pkipaths/qgsauthpkipathsedit.cpp
@@ -162,10 +162,7 @@ void QgsAuthPkiPathsEdit::writePkiMessage( QLineEdit *lineedit, const QString &m
       txt = tr( "Invalid: %1" ).arg( msg );
       break;
     case Unknown:
-      ss = QLatin1String( "" );
       break;
-    default:
-      ss = QLatin1String( "" );
   }
   lineedit->setStyleSheet( ss );
   lineedit->setText( txt );

diff --git a/src/auth/pkipkcs12/qgsauthpkcs12edit.cpp b/src/auth/pkipkcs12/qgsauthpkcs12edit.cpp
@@ -167,10 +167,7 @@ void QgsAuthPkcs12Edit::writePkiMessage( QLineEdit *lineedit, const QString &msg
       txt = tr( "Invalid: %1" ).arg( msg );
       break;
     case Unknown:
-      ss = QLatin1String( "" );
       break;
-    default:
-      ss = QLatin1String( "" );
   }
   lineedit->setStyleSheet( ss );
   lineedit->setText( txt );

diff --git a/src/core/annotations/qgshtmlannotation.cpp b/src/core/annotations/qgshtmlannotation.cpp
@@ -61,7 +61,7 @@ void QgsHtmlAnnotation::setSourceFile( const QString &htmlFile )
   mHtmlFile = htmlFile;
   if ( !file.open( QIODevice::ReadOnly | QIODevice::Text ) )
   {
-    mHtmlSource = QLatin1String( "" );
+    mHtmlSource.clear();
   }
   else
   {

diff --git a/src/core/auth/qgsauthmanager.cpp b/src/core/auth/qgsauthmanager.cpp
@@ -804,7 +804,7 @@ const QString QgsAuthManager::uniqueConfigId() const
 
   while ( true )
   {
-    id = QLatin1String( "" );
+    id.clear();
     for ( int i = 0; i < len; i++ )
     {
       switch ( qrand() % 2 )
@@ -3051,7 +3051,7 @@ void QgsAuthManager::setPasswordHelperLoggingEnabled( const bool enabled )
 void QgsAuthManager::passwordHelperClearErrors()
 {
   mPasswordHelperErrorCode = QKeychain::NoError;
-  mPasswordHelperErrorMessage = QLatin1String( "" );
+  mPasswordHelperErrorMessage.clear();
 }
 
 void QgsAuthManager::passwordHelperProcessError()

diff --git a/src/core/providers/memory/qgsmemoryprovider.cpp b/src/core/providers/memory/qgsmemoryprovider.cpp
@@ -158,22 +158,22 @@ QgsMemoryProvider::QgsMemoryProvider( const QString &uri )
           length = -1;
         }
 
-        if ( reFieldDef.cap( 2 ) != QLatin1String( "" ) )
+        if ( !reFieldDef.cap( 2 ).isEmpty() )
         {
           length = reFieldDef.cap( 2 ).toInt();
         }
-        if ( reFieldDef.cap( 3 ) != QLatin1String( "" ) )
+        if ( !reFieldDef.cap( 3 ).isEmpty() )
         {
           precision = reFieldDef.cap( 3 ).toInt();
         }
-        if ( reFieldDef.cap( 4 ) != QLatin1String( "" ) )
+        if ( !reFieldDef.cap( 4 ).isEmpty() )
         {
           //array
           subType = type;
           type = ( subType == QVariant::String ? QVariant::StringList : QVariant::List );
         }
       }
-      if ( name != QLatin1String( "" ) )
+      if ( !name.isEmpty() )
         attributes.append( QgsField( name, type, typeName, length, precision, QLatin1String( "" ), subType ) );
     }
     addAttributes( attributes );

diff --git a/src/core/qgscolorramp.cpp b/src/core/qgscolorramp.cpp
@@ -691,7 +691,7 @@ QgsStringMap QgsCptCityColorRamp::properties() const
 
 QString QgsCptCityColorRamp::fileName() const
 {
-  if ( mSchemeName == QLatin1String( "" ) )
+  if ( mSchemeName.isEmpty() )
     return QString();
   else
   {