Add const and std::as_const

src/core/database.cpp

@@ -21,6 +21,8 @@
 
 #include "config.h"
 
+#include <utility>
+
 #include <sqlite3.h>
 
 #include <QObject>
@@ -87,7 +89,8 @@ Database::~Database() {
 
   QMutexLocker l(&connect_mutex_);
 
-  for (const QString &connection_id : QSqlDatabase::connectionNames()) {
+  const QStringList connection_names = QSqlDatabase::connectionNames();
+  for (const QString &connection_id : connection_names) {
     qLog(Error) << "Connection" << connection_id << "is still open!";
   }
 
@@ -157,7 +160,7 @@ QSqlDatabase Database::Connect() {
 
   // Attach external databases
   QStringList keys = attached_databases_.keys();
-  for (const QString &key : keys) {
+  for (const QString &key : std::as_const(keys)) {
     QString filename = attached_databases_[key].filename_;
 
     if (!injected_database_name_.isNull()) filename = injected_database_name_;
@@ -178,7 +181,7 @@ QSqlDatabase Database::Connect() {
 
   // We might have to initialize the schema in some attached databases now, if they were deleted and don't match up with the main schema version.
   keys = attached_databases_.keys();
-  for (const QString &key : keys) {
+  for (const QString &key : std::as_const(keys)) {
     if (attached_databases_[key].is_temporary_ && attached_databases_[key].schema_.isEmpty()) {
       continue;
     }
@@ -276,7 +279,8 @@ void Database::RecreateAttachedDb(const QString &database_name) {
 
   // We can't just re-attach the database now because it needs to be done for each thread.
   // Close all the database connections, so each thread will re-attach it when they next connect.
-  for (const QString &name : QSqlDatabase::connectionNames()) {
+  const QStringList connection_names = QSqlDatabase::connectionNames();
+  for (const QString &name : connection_names) {
     QSqlDatabase::removeDatabase(name);
   }
 
@@ -384,8 +388,7 @@ void Database::ExecSchemaCommandsFromFile(QSqlDatabase &db, const QString &filen
 void Database::ExecSchemaCommands(QSqlDatabase &db, const QString &schema, int schema_version, bool in_transaction) {
 
   // Run each command
-  QStringList commands;
-  commands = schema.split(QRegularExpression(QStringLiteral("; *\n\n")));
+  QStringList commands = schema.split(QRegularExpression(QStringLiteral("; *\n\n")));
 
   // We don't want this list to reflect possible DB schema changes, so we initialize it before executing any statements.
   // If no outer transaction is provided the song tables need to be queried before beginning an inner transaction!
@@ -445,12 +448,13 @@ QStringList Database::SongsTables(QSqlDatabase &db, const int schema_version) {
   QStringList ret;
 
   // look for the tables in the main db
-  for (const QString &table : db.tables()) {
+  const QStringList &tables = db.tables();
+  for (const QString &table : tables) {
     if (table == QStringLiteral("songs") || table.endsWith(QLatin1String("_songs"))) ret << table;
   }
 
   // look for the tables in attached dbs
-  QStringList keys = attached_databases_.keys();
+  const QStringList keys = attached_databases_.keys();
   for (const QString &key : keys) {
     SqlQuery q(db);
     q.prepare(QStringLiteral("SELECT NAME FROM %1.sqlite_master WHERE type='table' AND name='songs' OR name LIKE '%songs'").arg(key));

src/core/iconloader.cpp

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include <utility>
+
 #include <QDir>
 #include <QFile>
 #include <QList>
@@ -80,7 +82,8 @@ QIcon IconLoader::Load(const QString &name, const bool system_icon, const int fi
     if (icon_prop.allow_system_icon) {
       ret = QIcon::fromTheme(name);
       if (ret.isNull()) {
-        for (const QString &alt_name : icon_prop.names) {
+        const QStringList alt_names = icon_prop.names;
+        for (const QString &alt_name : alt_names) {
           ret = QIcon::fromTheme(alt_name);
           if (!ret.isNull()) break;
         }
@@ -96,7 +99,8 @@ QIcon IconLoader::Load(const QString &name, const bool system_icon, const int fi
         else {
           int size_smallest = 0;
           int size_largest = 0;
-          for (const QSize &s : ret.availableSizes()) {
+          const QList<QSize> available_sizes = ret.availableSizes();
+          for (const QSize &s : available_sizes) {
             if (s.width() != s.height()) {
               qLog(Warning) << "Can't use system icon for" << name << "icon is not proportional.";
               ret = QIcon();
@@ -120,7 +124,7 @@ QIcon IconLoader::Load(const QString &name, const bool system_icon, const int fi
 
   if (custom_icons_) {
     QString custom_icon_path = QStandardPaths::writableLocation(QStandardPaths::AppLocalDataLocation) + QStringLiteral("/icons/%1x%2/%3.png");
-    for (int s : sizes) {
+    for (int s : std::as_const(sizes)) {
       QString filename(custom_icon_path.arg(s).arg(s).arg(name));
       if (QFile::exists(filename)) ret.addFile(filename, QSize(s, s));
     }
@@ -129,7 +133,7 @@ QIcon IconLoader::Load(const QString &name, const bool system_icon, const int fi
   }
 
   const QString path(QStringLiteral(":/icons/%1x%2/%3.png"));
-  for (int s : sizes) {
+  for (int s : std::as_const(sizes)) {
     QString filename(path.arg(s).arg(s).arg(name));
     if (QFile::exists(filename)) ret.addFile(filename, QSize(s, s));
   }

src/core/mergedproxymodel.cpp

@@ -424,7 +424,7 @@ QStringList MergedProxyModel::mimeTypes() const {
   QStringList ret;
   ret << sourceModel()->mimeTypes();
 
-  QList<QAbstractItemModel*> models = merge_points_.keys();
+  const QList<QAbstractItemModel*> models = merge_points_.keys();
   for (const QAbstractItemModel *model : models) {
     ret << model->mimeTypes();
   }
@@ -506,7 +506,7 @@ QAbstractItemModel *MergedProxyModel::GetModel(const QModelIndex &source_index)
   // This is essentially const_cast<QAbstractItemModel*>(source_index.model()), but without the const_cast
   const QAbstractItemModel *const_model = source_index.model();
   if (const_model == sourceModel()) return sourceModel();
-  QList<QAbstractItemModel*> submodels = merge_points_.keys();
+  const QList<QAbstractItemModel*> submodels = merge_points_.keys();
   for (QAbstractItemModel *submodel : submodels) {
     if (submodel == const_model) return submodel;
   }
@@ -522,7 +522,7 @@ void MergedProxyModel::DataChanged(const QModelIndex &top_left, const QModelInde
 void MergedProxyModel::LayoutAboutToBeChanged() {
 
   old_merge_points_.clear();
-  QList<QAbstractItemModel*> models = merge_points_.keys();
+  const QList<QAbstractItemModel*> models = merge_points_.keys();
   for (QAbstractItemModel *model : models) {
     old_merge_points_[model] = merge_points_.value(model);
   }
@@ -531,7 +531,7 @@ void MergedProxyModel::LayoutAboutToBeChanged() {
 
 void MergedProxyModel::LayoutChanged() {
 
-  QList<QAbstractItemModel*> models = merge_points_.keys();
+  const QList<QAbstractItemModel*> models = merge_points_.keys();
   for (QAbstractItemModel *model : models) {
     if (!old_merge_points_.contains(model)) continue;
 

src/core/networkproxyfactory.cpp

@@ -44,11 +44,10 @@ NetworkProxyFactory::NetworkProxyFactory()
 #ifdef Q_OS_LINUX
   // Linux uses environment variables to pass proxy configuration information, which systemProxyForQuery doesn't support for some reason.
 
-  QStringList urls;
-  urls << QString::fromLocal8Bit(qgetenv("HTTP_PROXY"));
-  urls << QString::fromLocal8Bit(qgetenv("http_proxy"));
-  urls << QString::fromLocal8Bit(qgetenv("ALL_PROXY"));
-  urls << QString::fromLocal8Bit(qgetenv("all_proxy"));
+  const QStringList urls = QStringList() << QString::fromLocal8Bit(qgetenv("HTTP_PROXY"))
+                                         << QString::fromLocal8Bit(qgetenv("http_proxy"))
+                                         << QString::fromLocal8Bit(qgetenv("ALL_PROXY"))
+                                         << QString::fromLocal8Bit(qgetenv("all_proxy"));
 
   qLog(Debug) << "Detected system proxy URLs:" << urls;
 

src/core/player.cpp

@@ -437,7 +437,8 @@ void Player::PlayPlaylistInternal(const EngineBase::TrackChangeFlags change, con
   play_offset_nanosec_ = 0;
 
   Playlist *playlist = nullptr;
-  for (Playlist *p : app_->playlist_manager()->GetAllPlaylists()) {
+  const QList<Playlist*> playlists = app_->playlist_manager()->GetAllPlaylists();
+  for (Playlist *p : playlists) {
     if (playlist_name == app_->playlist_manager()->GetPlaylistName(p->id())) {
       playlist = p;
       break;

src/core/stylehelper.cpp

@@ -176,7 +176,8 @@ void StyleHelper::setBaseColor(const QColor &newcolor) {
 
   if (color.isValid() && color != m_baseColor) {
     m_baseColor = color;
-    for (QWidget *w : QApplication::topLevelWidgets()) {
+    const QList<QWidget*> widgets = QApplication::topLevelWidgets();
+    for (QWidget *w : widgets) {
       w->update();
     }
   }

src/core/translations.cpp

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include <utility>
+
 #include <QCoreApplication>
 #include <QTranslator>
 #include <QString>
@@ -29,7 +31,7 @@
 Translations::Translations(QObject *parent) : QObject(parent) {}
 Translations::~Translations() {
 
-  for (QTranslator *t : translations_) {
+  for (QTranslator *t : std::as_const(translations_)) {
     QCoreApplication::removeTranslator(t);
     delete t;
   }