Replace null pointer constants (e.g. NULL, 0) with nullptr

27 files changed, 114 insertions, 107 deletions

diff --git a/src/library/autodj/autodjprocessor.cpp b/src/library/autodj/autodjprocessor.cpp
index 029876bbb3..b9506a6133 100644
--- a/src/library/autodj/autodjprocessor.cpp
+++ b/src/library/autodj/autodjprocessor.cpp
@@ -105,7 +105,7 @@ void DeckAttributes::slotRateChanged(double v) {
 }
 
 TrackPointer DeckAttributes::getLoadedTrack() const {
-    return m_pPlayer != NULL ? m_pPlayer->getLoadedTrack() : TrackPointer();
+    return m_pPlayer != nullptr ? m_pPlayer->getLoadedTrack() : TrackPointer();
 }
 
 AutoDJProcessor::AutoDJProcessor(
@@ -117,7 +117,7 @@ AutoDJProcessor::AutoDJProcessor(
         : QObject(pParent),
           m_pConfig(pConfig),
           m_pPlayerManager(pPlayerManager),
-          m_pAutoDJTableModel(NULL),
+          m_pAutoDJTableModel(nullptr),
           m_eState(ADJ_DISABLED),
           m_transitionProgress(0.0),
           m_transitionTime(kTransitionPreferenceDefault) {
@@ -153,7 +153,7 @@ AutoDJProcessor::AutoDJProcessor(
         QString group = PlayerManager::groupForDeck(i);
         BaseTrackPlayer* pPlayer = pPlayerManager->getPlayer(group);
         // Shouldn't be possible.
-        if (pPlayer == NULL) {
+        if (pPlayer == nullptr) {
             qWarning() << "PROGRAMMING ERROR deck does not exist" << i;
             continue;
         }
diff --git a/src/library/autodj/dlgautodj.cpp b/src/library/autodj/dlgautodj.cpp
index f56c0054e4..13302d2abf 100644
--- a/src/library/autodj/dlgautodj.cpp
+++ b/src/library/autodj/dlgautodj.cpp
@@ -273,16 +273,16 @@ void DlgAutoDJ::toggleAutoDJButton(bool enable) {
     AutoDJProcessor::AutoDJError error = m_pAutoDJProcessor->toggleAutoDJ(enable);
     switch (error) {
         case AutoDJProcessor::ADJ_BOTH_DECKS_PLAYING:
-            QMessageBox::warning(
-                    NULL, tr("Auto DJ"),
+            QMessageBox::warning(nullptr,
+                    tr("Auto DJ"),
                     tr("One deck must be stopped to enable Auto DJ mode."),
                     QMessageBox::Ok);
             // Make sure the button becomes unpushed.
             pushButtonAutoDJ->setChecked(false);
             break;
         case AutoDJProcessor::ADJ_DECKS_3_4_PLAYING:
-            QMessageBox::warning(
-                    NULL, tr("Auto DJ"),
+            QMessageBox::warning(nullptr,
+                    tr("Auto DJ"),
                     tr("Decks 3 and 4 must be stopped to enable Auto DJ mode."),
                     QMessageBox::Ok);
             pushButtonAutoDJ->setChecked(false);
diff --git a/src/library/banshee/bansheefeature.cpp b/src/library/banshee/bansheefeature.cpp
index faed634666..182cee18f6 100644
--- a/src/library/banshee/bansheefeature.cpp
+++ b/src/library/banshee/bansheefeature.cpp
@@ -72,19 +72,19 @@ void BansheeFeature::activate() {
 
         if (!QFile::exists(m_databaseFile)) {
             QMessageBox::warning(
-                    NULL,
+                    nullptr,
                     tr("Error loading Banshee database"),
                     tr("Banshee database file not found at\n") +
-                    m_databaseFile);
+                            m_databaseFile);
             qDebug() << m_databaseFile << "does not exist";
         }
 
         if (!m_connection.open(m_databaseFile)) {
             QMessageBox::warning(
-                    NULL,
+                    nullptr,
                     tr("Error loading Banshee database"),
                     tr("There was an error loading your Banshee database at\n") +
-                    m_databaseFile);
+                            m_databaseFile);
             return;
         }
 
diff --git a/src/library/baseexternallibraryfeature.cpp b/src/library/baseexternallibraryfeature.cpp
index de0caabd5f..8f1ef33cd2 100644
--- a/src/library/baseexternallibraryfeature.cpp
+++ b/src/library/baseexternallibraryfeature.cpp
@@ -117,10 +117,9 @@ void BaseExternalLibraryFeature::slotImportAsMixxxPlaylist() {
     } else {
         // Do not change strings here without also changing strings in
         // src/library/baseplaylistfeature.cpp
-        QMessageBox::warning(NULL,
-                             tr("Playlist Creation Failed"),
-                             tr("An unknown error occurred while creating playlist: ")
-                             + playlist);
+        QMessageBox::warning(nullptr,
+                tr("Playlist Creation Failed"),
+                tr("An unknown error occurred while creating playlist: ") + playlist);
     }
 }
 
diff --git a/src/library/baseplaylistfeature.cpp b/src/library/baseplaylistfeature.cpp
index 317a8bacbc..f7e8d8fca0 100644
--- a/src/library/baseplaylistfeature.cpp
+++ b/src/library/baseplaylistfeature.cpp
@@ -193,7 +193,7 @@ void BasePlaylistFeature::slotRenamePlaylist() {
 
     while (!validNameGiven) {
         bool ok = false;
-        newName = QInputDialog::getText(NULL,
+        newName = QInputDialog::getText(nullptr,
                 tr("Rename Playlist"),
                 tr("Enter new name for playlist:"),
                 QLineEdit::Normal,
@@ -207,11 +207,11 @@ void BasePlaylistFeature::slotRenamePlaylist() {
         int existingId = m_playlistDao.getPlaylistIdFromName(newName);
 
         if (existingId != -1) {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Renaming Playlist Failed"),
                     tr("A playlist by that name already exists."));
         } else if (newName.isEmpty()) {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Renaming Playlist Failed"),
                     tr("A playlist cannot have a blank name."));
         } else {
@@ -235,7 +235,7 @@ void BasePlaylistFeature::slotDuplicatePlaylist() {
 
     while (!validNameGiven) {
         bool ok = false;
-        name = QInputDialog::getText(NULL,
+        name = QInputDialog::getText(nullptr,
                 tr("Duplicate Playlist"),
                 tr("Enter name for new playlist:"),
                 QLineEdit::Normal,
@@ -250,11 +250,11 @@ void BasePlaylistFeature::slotDuplicatePlaylist() {
         int existingId = m_playlistDao.getPlaylistIdFromName(name);
 
         if (existingId != -1) {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Playlist Creation Failed"),
                     tr("A playlist by that name already exists."));
         } else if (name.isEmpty()) {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Playlist Creation Failed"),
                     tr("A playlist cannot have a blank name."));
         } else {
@@ -288,7 +288,7 @@ void BasePlaylistFeature::slotCreatePlaylist() {
 
     while (!validNameGiven) {
         bool ok = false;
-        name = QInputDialog::getText(NULL,
+        name = QInputDialog::getText(nullptr,
                 tr("Create New Playlist"),
                 tr("Enter name for new playlist:"),
                 QLineEdit::Normal,
@@ -302,11 +302,11 @@ void BasePlaylistFeature::slotCreatePlaylist() {
         int existingId = m_playlistDao.getPlaylistIdFromName(name);
 
         if (existingId != -1) {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Playlist Creation Failed"),
                     tr("A playlist by that name already exists."));
         } else if (name.isEmpty()) {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Playlist Creation Failed"),
                     tr("A playlist cannot have a blank name."));
         } else {
@@ -319,7 +319,7 @@ void BasePlaylistFeature::slotCreatePlaylist() {
     if (playlistId != -1) {
         activatePlaylist(playlistId);
     } else {
-        QMessageBox::warning(NULL,
+        QMessageBox::warning(nullptr,
                 tr("Playlist Creation Failed"),
                 tr("An unknown error occurred while creating playlist: ") + name);
     }
@@ -370,7 +370,7 @@ void BasePlaylistFeature::slotImportPlaylistFile(const QString& playlist_file) {
     // folder. We don't need access to this file on a regular basis so we do not
     // register a security bookmark.
 
-    Parser* playlist_parser = NULL;
+    Parser* playlist_parser = nullptr;
 
     if (playlist_file.endsWith(".m3u", Qt::CaseInsensitive) ||
             playlist_file.endsWith(".m3u8", Qt::CaseInsensitive)) {
@@ -435,7 +435,7 @@ void BasePlaylistFeature::slotCreateImportPlaylist() {
         if (lastPlaylistId != -1) {
             m_pPlaylistTableModel->setTableModel(lastPlaylistId);
         } else {
-            QMessageBox::warning(NULL,
+            QMessageBox::warning(nullptr,
                     tr("Playlist Creation Failed"),
                     tr("An unknown error occurred while creating playlist: ") + name);
             return;
@@ -463,7 +463,7 @@ void BasePlaylistFeature::slotExportPlaylist() {
     // name to the playlist name.
     QString filefilter = tr("M3U Playlist (*.m3u)");
     QString file_location = QFileDialog::getSaveFileName(
-            NULL,
+            nullptr,
             tr("Export Playlist"),
             lastPlaylistDirectory.append("/").append(playlistName),
             tr("M3U Playlist (*.m3u);;M3U8 Playlist (*.m3u8);;"
diff --git a/src/library/bpmdelegate.cpp b/src/library/bpmdelegate.cpp
index 6c8b5d8eb5..695a17450a 100644
--- a/src/library/bpmdelegate.cpp
+++ b/src/library/bpmdelegate.cpp
@@ -79,9 +79,9 @@ void BPMDelegate::paintItem(QPainter* painter,const QStyleOptionViewItem &option
     QStyleOptionViewItem opt = option;
     initStyleOption(&opt, index);
 
-    if (m_pTableView != NULL) {
+    if (m_pTableView != nullptr) {
         QStyle* style = m_pTableView->style();
-        if (style != NULL) {
+        if (style != nullptr) {
             style->drawControl(QStyle::CE_ItemViewItem, &opt, painter,
                                m_pCheckBox);
         }
diff --git a/src/library/browse/browsetablemodel.cpp b/src/library/browse/browsetablemodel.cpp
index 6d1ac08f92..05acc20f94 100644
--- a/src/library/browse/browsetablemodel.cpp
+++ b/src/library/browse/browsetablemodel.cpp
@@ -196,10 +196,9 @@ TrackPointer BrowseTableModel::getTrack(const QModelIndex& index) const {
 TrackPointer BrowseTableModel::getTrackByRef(const TrackRef& trackRef) const {
     if (m_pRecordingManager->getRecordingLocation() == trackRef.getLocation()) {
         QMessageBox::critical(
-            0, tr("Mixxx Library"),
-            tr("Could not load the following file because"
-               " it is in use by Mixxx or another application.")
-            + "\n" + trackRef.getLocation());
+                nullptr, tr("Mixxx Library"), tr("Could not load the following file because"
+                                                 " it is in use by Mixxx or another application.") +
+                        "\n" + trackRef.getLocation());
         return TrackPointer();
     }
     // NOTE(uklotzde, 2015-12-08): Accessing tracks from the browse view
diff --git a/src/library/browse/browsethread.cpp b/src/library/browse/browsethread.cpp
index eae977680b..75e3d27333 100644
--- a/src/library/browse/browsethread.cpp
+++ b/src/library/browse/browsethread.cpp
@@ -33,7 +33,7 @@ static QMutex s_Mutex;
 BrowseThread::BrowseThread(QObject *parent)
         : QThread(parent) {
     m_bStopThread = false;
-    m_model_observer = NULL;
+    m_model_observer = nullptr;
     //start Thread
     start(QThread::LowPriority);
 
diff --git a/src/library/browse/foldertreemodel.cpp b/src/library/browse/foldertreemodel.cpp
index a763136b48..e1d03d1fdd 100644
--- a/src/library/browse/foldertreemodel.cpp
+++ b/src/library/browse/foldertreemodel.cpp
@@ -93,9 +93,9 @@ bool FolderTreeModel::directoryHasChildren(const QString& path) const {
     DIR *directory = opendir(ba);
     int unknown_count = 0;
     int total_count = 0;
-    if (directory != NULL) {
+    if (directory != nullptr) {
         struct dirent *entry;
-        while (!has_children && ((entry = readdir(directory)) != NULL)) {
+        while (!has_children && ((entry = readdir(directory)) != nullptr)) {
             if (entry->d_name != dot && entry->d_name != dotdot) {
                 total_count++;
                 if (entry->d_type == DT_UNKNOWN) {
@@ -110,7 +110,7 @@ bool FolderTreeModel::directoryHasChildren(const QString& path) const {
     // If all files are of type DH_UNKNOWN then do a costlier analysis to
     // determine if the directory has subdirectories. This affects folders on
     // filesystems that do not fully implement readdir such as JFS.
-    if (directory == NULL || (unknown_count == total_count && total_count > 0)) {
+    if (directory == nullptr || (unknown_count == total_count && total_count > 0)) {
         QDir dir(path);
         QFileInfoList all = dir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot);
         has_children = all.count() > 0;
diff --git a/src/library/coverartutils.cpp b/src/library/coverartutils.cpp
index e70404b43d..7a750a4e42 100644
--- a/src/library/coverartutils.cpp
+++ b/src/library/coverartutils.cpp
@@ -93,7 +93,7 @@ CoverInfoRelative CoverArtUtils::selectCoverArtForTrack(
     }
 
     PreferredCoverType bestType = NONE;
-    const QFileInfo* bestInfo = NULL;
+    const QFileInfo* bestInfo = nullptr;
 
     // If there is a single image then we use it unconditionally. Otherwise
     // we use the priority order described in PreferredCoverType. Notably,
@@ -143,7 +143,7 @@ CoverInfoRelative CoverArtUtils::selectCoverArtForTrack(
         }
     }
 
-    if (bestInfo != NULL) {
+    if (bestInfo != nullptr) {
         QImage image(bestInfo->filePath());
         if (!image.isNull()) {
             coverInfoRelative.type = CoverInfo::FILE;
diff --git a/src/library/crate/cratefeature.cpp b/src/library/crate/cratefeature.cpp
index d977f95f17..2d0de89876 100644
--- a/src/library/crate/cratefeature.cpp
+++ b/src/library/crate/cratefeature.cpp
@@ -686,11 +686,11 @@ void CrateFeature::slotExportPlaylist() {
             ConfigKey("[Library]", "LastImportExportCrateDirectory"),
             QStandardPaths::writableLocation(QStandardPaths::MusicLocation));
 
-    QString file_location = QFileDialog::getSaveFileName(
-        NULL,
-        tr("Export Crate"),
-        lastCrateDirectory.append("/").append(crate.getName()),
-        tr("M3U Playlist (*.m3u);;M3U8 Playlist (*.m3u8);;PLS Playlist (*.pls);;Text CSV (*.csv);;Readable Text (*.txt)"));
+    QString file_location = QFileDialog::getSaveFileName(nullptr,
+            tr("Export Crate"),
+            lastCrateDirectory.append("/").append(crate.getName()),
+            tr("M3U Playlist (*.m3u);;M3U8 Playlist (*.m3u8);;PLS Playlist "
+               "(*.pls);;Text CSV (*.csv);;Readable Text (*.txt)"));
     // Exit method if user cancelled the open dialog.
     if (file_location.isNull() || file_location.isEmpty()) {
         return;
diff --git a/src/library/dao/analysisdao.cpp b/src/library/dao/analysisdao.cpp
index ff7ca74783..1e8d2faa2d 100644
--- a/src/library/dao/analysisdao.cpp
+++ b/src/library/dao/analysisdao.cpp
@@ -103,7 +103,7 @@ QList<AnalysisDao::AnalysisInfo> AnalysisDao::loadAnalysesFromQuery(TrackId trac
 }
 
 bool AnalysisDao::saveAnalysis(AnalysisDao::AnalysisInfo* info) {
-    if (!m_database.isOpen() || info == NULL) {
+    if (!m_database.isOpen() || info == nullptr) {
         return false;
     }
 
diff --git a/src/library/dao/autodjcratesdao.cpp b/src/library/dao/autodjcratesdao.cpp
index 02bacbca90..fd0a702eeb 100644
--- a/src/library/dao/autodjcratesdao.cpp
+++ b/src/library/dao/autodjcratesdao.cpp
@@ -1078,7 +1078,7 @@ void AutoDJCratesDAO::slotPlaylistTrackRemoved(int playlistId,
 void AutoDJCratesDAO::slotPlayerInfoTrackLoaded(const QString& a_strGroup,
         TrackPointer a_pTrack) {
     // This gets called with a null track during an unload.  Filter that out.
-    if (a_pTrack == NULL) {
+    if (a_pTrack == nullptr) {
         return;
     }
 
diff --git a/src/library/export/trackexportdlg.cpp b/src/library/export/trackexportdlg.cpp
index d185e39043..d6c6c0335e 100644
--- a/src/library/export/trackexportdlg.cpp
+++ b/src/library/export/trackexportdlg.cpp
@@ -106,9 +106,11 @@ void TrackExportDlg::finish() {
     m_worker->wait();
     if (m_worker->errorMessage().length()) {
         QMessageBox::warning(
-                NULL,
-                tr("Export Error"), m_worker->errorMessage(),
-                QMessageBox::Ok, QMessageBox::Ok);
+                nullptr,
+                tr("Export Error"),
+                m_worker->errorMessage(),
+                QMessageBox::Ok,
+                QMessageBox::Ok);
     }
     hide();
     accept();
diff --git a/src/library/export/trackexportwizard.cpp b/src/library/export/trackexportwizard.cpp
index 12aee6081a..932b865b3f 100644
--- a/src/library/export/trackexportwizard.cpp
+++ b/src/library/export/trackexportwizard.cpp
@@ -22,7 +22,7 @@ bool TrackExportWizard::selectDestinationDirectory() {
             QStandardPaths::writableLocation(QStandardPaths::MusicLocation));
 
     QString destDir = QFileDialog::getExistingDirectory(
-            NULL, tr("Export Track Files To"), lastExportDirectory);
+            nullptr, tr("Export Track Files To"), lastExportDirectory);
     if (destDir.isEmpty()) {
         return false;
     }
diff --git a/src/library/itunes/itunesfeature.cpp b/src/library/itunes/itunesfeature.cpp
index c0ae347120..df697bef00 100644
--- a/src/library/itunes/itunesfeature.cpp
+++ b/src/library/itunes/itunesfeature.cpp
@@ -194,7 +194,7 @@ void ITunesFeature::activate(bool forceReload) {
             // if the path we got between the default and the database doesn't
             // exist, ask for a new one and use/save it if it exists
             m_dbfile = QFileDialog::getOpenFileName(
-                NULL, tr("Select your iTunes library"), QDir::homePath(), "*.xml");
+                    nullptr, tr("Select your iTunes library"), QDir::homePath(), "*.xml");
             QFileInfo dbFile(m_dbfile);
             if (m_dbfile.isEmpty() || !dbFile.exists()) {
                 return;
@@ -249,7 +249,7 @@ void ITunesFeature::onRightClick(const QPoint& globalPos) {
     } else if (chosen == &chooseNew) {
         SettingsDAO settings(m_database);
         QString dbfile = QFileDialog::getOpenFileName(
-            NULL, tr("Select your iTunes library"), QDir::homePath(), "*.xml");
+                nullptr, tr("Select your iTunes library"), QDir::homePath(), "*.xml");
 
         QFileInfo dbFileInfo(dbfile);
         if (dbfile.isEmpty() || !dbFileInfo.exists()) {
@@ -390,11 +390,11 @@ TreeItem* ITunesFeature::importLibrary() {
     QFile itunes_file(m_dbfile);
     if (!itunes_file.open(QIODevice::ReadOnly | QIODevice::Text)) {
         qDebug() << "Cannot open iTunes music collection";
-        return NULL;
+        return nullptr;
     }
 
     QXmlStreamReader xml(&itunes_file);
-    TreeItem* playlist_root = NULL;
+    TreeItem* playlist_root = nullptr;
     while (!xml.atEnd() && !m_cancelImport) {
         xml.readNext();
         if (xml.isStartElement()) {
@@ -409,7 +409,7 @@ TreeItem* ITunesFeature::importLibrary() {
                     }
                 } else if (key == "Tracks") {
                     parseTracks(xml);
-                    if (playlist_root != NULL) {
+                    if (playlist_root != nullptr) {
                         delete playlist_root;
                     }
                     playlist_root = parsePlaylists(xml);
@@ -448,7 +448,7 @@ TreeItem* ITunesFeature::importLibrary() {
         if (playlist_root) {
             delete playlist_root;
         }
-        playlist_root = NULL;
+        playlist_root = nullptr;
     }
     return playlist_root;
 }
@@ -823,10 +823,10 @@ void ITunesFeature::onTrackCollectionLoaded() {
         qDebug() << "Itunes library loaded: success";
     } else {
         QMessageBox::warning(
-            NULL,
-            tr("Error Loading iTunes Library"),
-            tr("There was an error loading your iTunes library. Some of "
-               "your iTunes tracks or playlists may not have loaded."));
+                nullptr,
+                tr("Error Loading iTunes Library"),
+                tr("There was an error loading your iTunes library. Some of "
+                   "your iTunes tracks or playlists may not have loaded."));
     }
     // calls a slot in the sidebarmodel such that 'isLoading' is removed from the feature title.
     m_title = tr("iTunes");
diff --git a/src/library/library.cpp b/src/library/library.cpp
index e5f2c8ae8c..dec5cc5b3a 100644
--- a/src/library/library.cpp
+++ b/src/library/library.cpp
@@ -457,10 +457,11 @@ void Library::slotRequestAddDir(const QString& dir) {
     Sandbox::createSecurityToken(directory);
 
     if (!m_pTrackCollectionManager->addDirectory(dir)) {
-        QMessageBox::information(0, tr("Add Directory to Library"),
+        QMessageBox::information(nullptr,
+                tr("Add Directory to Library"),
                 tr("Could not add the directory to your library. Either this "
-                    "directory is already in your library or you are currently "
-                    "rescanning your library."));
+                   "directory is already in your library or you are currently "
+                   "rescanning your library."));
     }
     // set at least one directory in the config file so that it will be possible
     // to downgrade from 1.12
diff --git a/src/library/librarycontrol.cpp b/src/library/librarycontrol.cpp
index 5e85f351ef..3b73e36bbd 100644
--- a/src/library/librarycontrol.cpp
+++ b/src/library/librarycontrol.cpp
@@ -314,7 +314,7 @@ void LibraryControl::slotNumPreviewDecksChanged(double v) {
 
 void LibraryControl::bindSidebarWidget(WLibrarySidebar* pSidebarWidget) {
     if (m_pSidebarWidget) {
-        disconnect(m_pSidebarWidget, 0, this, 0);
+        disconnect(m_pSidebarWidget, nullptr, this, nullptr);
     }
     m_pSidebarWidget = pSidebarWidget;
     connect(m_pSidebarWidget,
@@ -326,7 +326,7 @@ void LibraryControl::bindSidebarWidget(WLibrarySidebar* pSidebarWidget) {
 void LibraryControl::bindLibraryWidget(WLibrary* pLibraryWidget, KeyboardEventFilter* pKeyboard) {
     Q_UNUSED(pKeyboard);
     if (m_pLibraryWidget) {
-        disconnect(m_pLibraryWidget, 0, this, 0);
+        disconnect(m_pLibraryWidget, nullptr, this, nullptr);
     }
     m_pLibraryWidget = pLibraryWidget;
     connect(m_pLibraryWidget,
@@ -337,7 +337,7 @@ void LibraryControl::bindLibraryWidget(WLibrary* pLibraryWidget, KeyboardEventFi
 
 void LibraryControl::bindSearchboxWidget(WSearchLineEdit* pSearchbox) {
     if (m_pSearchbox) {
-        disconnect(m_pSearchbox, 0, this, 0);
+        disconnect(m_pSearchbox, nullptr, this, nullptr);
     }
     m_pSearchbox = pSearchbox;
     connect(this,
diff --git a/src/library/libraryfeature.cpp b/src/library/libraryfeature.cpp
index 137667a36f..20de2aa318 100644
--- a/src/library/libraryfeature.cpp
+++ b/src/library/libraryfeature.cpp
@@ -31,10 +31,10 @@ QStringList LibraryFeature::getPlaylistFiles(QFileDialog::FileMode mode) const {
             ConfigKey("[Library]", "LastImportExportPlaylistDirectory"),
             QStandardPaths::writableLocation(QStandardPaths::MusicLocation));
 
-    QFileDialog dialog(NULL,
-                     tr("Import Playlist"),
-                     lastPlaylistDirectory,
-                     tr("Playlist Files (*.m3u *.m3u8 *.pls *.csv)"));
+    QFileDialog dialog(nullptr,
+            tr("Import Playlist"),
+            lastPlaylistDirectory,
+            tr("Playlist Files (*.m3u *.m3u8 *.pls *.csv)"));
     dialog.setAcceptMode(QFileDialog::AcceptOpen);
     dialog.setFileMode(mode);
     dialog.setModal(true);
@@ -75,12 +75,12 @@ bool LibraryFeature::exportPlaylistItemsIntoFile(
             playlistFilePath.append(QStringLiteral(".m3u"));
             if (QFileInfo::exists(playlistFilePath)) {
                 auto overwrite = QMessageBox::question(
-                        NULL,
+                        nullptr,
                         tr("Overwrite File?"),
                         tr("A playlist file with the name \"%1\" already exists.\n"
                            "The default \"m3u\" extension was added because none was specified.\n\n"
-                           "Do you really want to overwrite it?").arg(playlistFilePath)
-                );
+                           "Do you really want to overwrite it?")
+                                .arg(playlistFilePath));
                 if (overwrite != QMessageBox::StandardButton::Yes) {
                     return false;
                 }
diff --git a/src/library/parsercsv.cpp b/src/library/parsercsv.cpp
index 10f39fff30..0970a80d78 100644
--- a/src/library/parsercsv.cpp
+++ b/src/library/parsercsv.cpp
@@ -129,8 +129,9 @@ bool ParserCsv::writeCSVFile(const QString &file_str, BaseSqlTableModel* pPlayli
 
     QFile file(file_str);
     if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
-        QMessageBox::warning(NULL,tr("Playlist Export Failed"),
-                             tr("Could not create file")+" "+file_str);
+        QMessageBox::warning(nullptr,
+                tr("Playlist Export Failed"),
+                tr("Could not create file") + " " + file_str);
         return false;
     }
     //Base folder of file
@@ -201,8 +202,9 @@ bool ParserCsv::writeReadableTextFile(const QString &file_str, BaseSqlTableModel
 
     QFile file(file_str);
     if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
-        QMessageBox::warning(NULL,tr("Readable text Export Failed"),
-                             tr("Could not create file")+" "+file_str);
+        QMessageBox::warning(nullptr,
+                tr("Readable text Export Failed"),
+                tr("Could not create file") + " " + file_str);
         return false;
     }
 
diff --git a/src/library/parserm3u.cpp b/src/library/parserm3u.cpp
index cfab773c2b..fac4540a00 100644
--- a/src/library/parserm3u.cpp
+++ b/src/library/parserm3u.cpp
@@ -133,10 +133,12 @@ bool ParserM3u::writeM3UFile(const QString &file_str, const QList<QString> &item
         for (int i = 0; i < items.size(); ++i) {
             if (!codec->canEncode(items.at(i))) {
                 // filepath contains incompatible character
-                QMessageBox::warning(NULL,tr("Playlist Export Failed"),
-                                     tr("File path contains characters, not allowed in m3u playlists.\n") +
-                                     tr("Export a m3u8 playlist instead!\n") +
-                                     items.at(i));
+                QMessageBox::warning(nullptr,
+                        tr("Playlist Export Failed"),
+                        tr("File path contains characters, not allowed in m3u "
+                           "playlists.\n") +
+                                tr("Export a m3u8 playlist instead!\n") +
+                                items.at(i));
                 return false;
             }
         }
@@ -144,8 +146,9 @@ bool ParserM3u::writeM3UFile(const QString &file_str, const QList<QString> &item
 
     QFile file(file_str);
     if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
-        QMessageBox::warning(NULL,tr("Playlist Export Failed"),
-                             tr("Could not create file") + " " + file_str);
+        QMessageBox::warning(nullptr,
+                tr("Playlist Export Failed"),
+                tr("Could not create file") + " " + file_str);
         return false;
     }
 
diff --git a/src/library/parserpls.cpp b/src/library/parserpls.cpp
index d949b846d8..5e26bd2b50 100644
--- a/src/library/parserpls.cpp
+++ b/src/library/parserpls.cpp
@@ -132,8 +132,9 @@ bool ParserPls::writePLSFile(const QString &file_str, const QList<QString> &item
 {
     QFile file(file_str);
     if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
-        QMessageBox::warning(NULL,tr("Playlist Export Failed"),
-                             tr("Could not create file")+" "+file_str);
+        QMessageBox::warning(nullptr,
+                tr("Playlist Export Failed"),
+                tr("Could not create file") + " " + file_str);
         return false;
     }
     //Base folder of file
diff --git a/src/library/proxytrackmodel.cpp b/src/library/proxytrackmodel.cpp
index edb2dca060..35181e8397 100644
--- a/src/library/proxytrackmodel.cpp
+++ b/src/library/proxytrackmodel.cpp
@@ -105,7 +105,7 @@ void ProxyTrackModel::moveTrack(const QModelIndex& sourceIndex,
 }
 
 QAbstractItemDelegate* ProxyTrackModel::delegateForColumn(const int i, QObject* pParent) {
-    return m_pTrackModel ? m_pTrackModel->delegateForColumn(i, pParent) : NULL;
+    return m_pTrackModel ? m_pTrackModel->delegateForColumn(i, pParent) : nullptr;
 }
 
 TrackModel::CapabilitiesFlags ProxyTrackModel::getCapabilities() const {
@@ -122,7 +122,7 @@ bool ProxyTrackModel::filterAcceptsRow(int sourceRow,
         return QSortFilterProxyModel::filterAcceptsRow(sourceRow, sourceParent);
     }
 
-    if (m_pTrackModel == NULL) {
+    if (m_pTrackModel == nullptr) {
         return false;
     }
 
@@ -149,14 +149,14 @@ bool ProxyTrackModel::filterAcceptsRow(int sourceRow,
 }
 
 QString ProxyTrackModel::getModelSetting(const QString& name) {
-    if (m_pTrackModel == NULL) {
+    if (m_pTrackModel == nullptr) {