Improve readability and type-safety

Use nullptr instead of 0 or NULL to initialize a null pointer. In some
cases, readability was enhanced by replacing 0 with more meaningful
values according to the type of the pointer being initialized.

src/autotype/AutoType.cpp

@@ -43,7 +43,7 @@ AutoType::AutoType(QObject* parent, bool test)
     : QObject(parent)
     , m_autoTypeDelay(0)
     , m_currentGlobalKey(static_cast<Qt::Key>(0))
-    , m_currentGlobalModifiers(0)
+    , m_currentGlobalModifiers(nullptr)
     , m_pluginLoader(new QPluginLoader(this))
     , m_plugin(nullptr)
     , m_executor(nullptr)

src/autotype/ShortcutWidget.cpp

@@ -24,7 +24,7 @@
 ShortcutWidget::ShortcutWidget(QWidget* parent)
     : QLineEdit(parent)
     , m_key(static_cast<Qt::Key>(0))
-    , m_modifiers(0)
+    , m_modifiers(nullptr)
     , m_locked(false)
 {
     setReadOnly(true);
@@ -58,7 +58,7 @@ void ShortcutWidget::setShortcut(Qt::Key key, Qt::KeyboardModifiers modifiers)
 void ShortcutWidget::resetShortcut()
 {
     m_key = static_cast<Qt::Key>(0);
-    m_modifiers = 0;
+    m_modifiers = nullptr;
     m_locked = false;
     autoType()->unregisterGlobalShortcut();
 }

src/autotype/xcb/AutoTypeXCB.cpp

@@ -50,7 +50,7 @@ AutoTypePlatformX11::AutoTypePlatformX11()
                      << "xfce4-panel"; // Xfce 4
 
     m_currentGlobalKey = static_cast<Qt::Key>(0);
-    m_currentGlobalModifiers = 0;
+    m_currentGlobalModifiers = nullptr;
 
     m_keysymTable = nullptr;
     m_xkb = nullptr;
@@ -197,7 +197,7 @@ void AutoTypePlatformX11::unregisterGlobalShortcut(Qt::Key key, Qt::KeyboardModi
     XUngrabKey(m_dpy, keycode, nativeModifiers | Mod2Mask | LockMask, m_rootWindow);
 
     m_currentGlobalKey = static_cast<Qt::Key>(0);
-    m_currentGlobalModifiers = 0;
+    m_currentGlobalModifiers = nullptr;
     m_currentGlobalKeycode = 0;
     m_currentGlobalNativeModifiers = 0;
 }
@@ -496,7 +496,7 @@ void AutoTypePlatformX11::updateKeymap()
     m_xkb = getKeyboard();
 
     XDisplayKeycodes(m_dpy, &m_minKeycode, &m_maxKeycode);
-    if (m_keysymTable != NULL)
+    if (m_keysymTable != nullptr)
         XFree(m_keysymTable);
     m_keysymTable = XGetKeyboardMapping(m_dpy, m_minKeycode, m_maxKeycode - m_minKeycode + 1, &m_keysymPerKeycode);
 

src/browser/BrowserEntryConfig.h

@@ -35,7 +35,7 @@ class BrowserEntryConfig : public QObject
     Q_PROPERTY(QString Realm READ realm WRITE setRealm)
 
 public:
-    BrowserEntryConfig(QObject* object = 0);
+    BrowserEntryConfig(QObject* object = nullptr);
 
     bool load(const Entry* entry);
     void save(Entry* entry);

src/browser/BrowserService.cpp

@@ -481,16 +481,16 @@ void BrowserService::convertAttributesToCustomData(Database *currentDb)
     progress.reset();
 
     if (counter > 0) {
-        QMessageBox::information(0, tr("KeePassXC: Converted KeePassHTTP attributes"),
+        QMessageBox::information(nullptr, tr("KeePassXC: Converted KeePassHTTP attributes"),
                                  tr("Successfully converted attributes from %1 entry(s).\n"
                                     "Moved %2 keys to custom data.", "").arg(counter).arg(keyCounter),
                                  QMessageBox::Ok);
     } else if (counter == 0 && keyCounter > 0) {
-        QMessageBox::information(0, tr("KeePassXC: Converted KeePassHTTP attributes"),
+        QMessageBox::information(nullptr, tr("KeePassXC: Converted KeePassHTTP attributes"),
                                  tr("Successfully moved %n keys to custom data.", "", keyCounter),
                                  QMessageBox::Ok);
     } else {
-        QMessageBox::information(0, tr("KeePassXC: No entry with KeePassHTTP attributes found!"),
+        QMessageBox::information(nullptr, tr("KeePassXC: No entry with KeePassHTTP attributes found!"),
                                  tr("The active database does not contain an entry with KeePassHTTP attributes."),
                                  QMessageBox::Ok);
     }

src/browser/HostInstaller.cpp

@@ -111,7 +111,7 @@ void HostInstaller::installBrowser(SupportedBrowsers browser,
         // Always create the script file
         QJsonObject script = constructFile(browser, proxy, location);
         if (!saveFile(browser, script)) {
-            QMessageBox::critical(0,
+            QMessageBox::critical(nullptr,
                                   tr("KeePassXC: Cannot save file!"),
                                   tr("Cannot save the native messaging script file."),
                                   QMessageBox::Ok);

src/browser/NativeMessagingHost.h

@@ -31,7 +31,7 @@ class NativeMessagingHost : public NativeMessagingBase
     typedef QList<QLocalSocket*> SocketList;
 
 public:
-    explicit NativeMessagingHost(DatabaseTabWidget* parent = 0, const bool enabled = false);
+    explicit NativeMessagingHost(DatabaseTabWidget* parent = nullptr, const bool enabled = false);
     ~NativeMessagingHost();
     int init();
     void run();

src/core/PasswordGenerator.cpp

@@ -25,15 +25,15 @@ const char* PasswordGenerator::DefaultExcludedChars = "";
 
 PasswordGenerator::PasswordGenerator()
     : m_length(0)
-    , m_classes(0)
+    , m_classes(nullptr)
-    , m_flags(0)
+    , m_flags(nullptr)
     , m_excluded(PasswordGenerator::DefaultExcludedChars)
 {
 }
 
 double PasswordGenerator::calculateEntropy(const QString& password)
 {
-    return ZxcvbnMatch(password.toLatin1(), 0, 0);
+    return ZxcvbnMatch(password.toLatin1(), nullptr, nullptr);
 }
 
 void PasswordGenerator::setLength(int length)

src/core/ScreenLockListenerPrivate.h

@@ -24,10 +24,10 @@ class ScreenLockListenerPrivate : public QObject
 {
     Q_OBJECT
 public:
-    static ScreenLockListenerPrivate* instance(QWidget* parent = 0);
+    static ScreenLockListenerPrivate* instance(QWidget* parent = nullptr);
 
 protected:
-    ScreenLockListenerPrivate(QWidget* parent = 0);
+    ScreenLockListenerPrivate(QWidget* parent = nullptr);
 
 signals:
     void screenLocked();

src/core/ScreenLockListenerWin.h

@@ -27,7 +27,7 @@ class ScreenLockListenerWin : public ScreenLockListenerPrivate, public QAbstract
 {
     Q_OBJECT
 public:
-    explicit ScreenLockListenerWin(QWidget* parent = 0);
+    explicit ScreenLockListenerWin(QWidget* parent = nullptr);
     ~ScreenLockListenerWin();
     virtual bool nativeEventFilter(const QByteArray& eventType, void* message, long*) override;
 

src/crypto/Crypto.cpp

@@ -336,4 +336,4 @@ bool Crypto::testChaCha20()
     }
 
     return true;
-}
+}

src/gui/CategoryListWidget.h

@@ -35,7 +35,7 @@ class CategoryListWidget : public QWidget
     Q_OBJECT
 
 public:
-    CategoryListWidget(QWidget* parent = 0);
+    CategoryListWidget(QWidget* parent = nullptr);
     ~CategoryListWidget();
 
     int currentCategory();
@@ -90,4 +90,4 @@ private:
     Q_DISABLE_COPY(CategoryListWidgetDelegate)
 };
 
-#endif
+#endif

src/gui/DatabaseOpenWidget.cpp

@@ -122,7 +122,7 @@ void DatabaseOpenWidget::hideEvent(QHideEvent* event)
 
 #ifdef WITH_XC_YUBIKEY
     // Don't listen to any Yubikey events if we are hidden
-    disconnect(YubiKey::instance(), 0, this, 0);
+    disconnect(YubiKey::instance(), nullptr, this, nullptr);
     m_yubiKeyBeingPolled = false;
 #endif
 }

src/gui/DatabaseTabWidget.cpp

@@ -419,7 +419,7 @@ bool DatabaseTabWidget::saveDatabaseAs(Database* db)
                                                             oldFilePath,
                                                             tr("KeePass 2 Database").append(" (*.kdbx)"),
                                                             nullptr,
-                                                            0,
+                                                            nullptr,
                                                             "kdbx");
         if (!newFilePath.isEmpty()) {
             // Ensure we don't recurse back into this function
@@ -488,7 +488,7 @@ void DatabaseTabWidget::exportToCsv()
     }
 
     QString fileName = fileDialog()->getSaveFileName(
-        this, tr("Export database to CSV file"), QString(), tr("CSV file").append(" (*.csv)"), nullptr, 0, "csv");
+        this, tr("Export database to CSV file"), QString(), tr("CSV file").append(" (*.csv)"), nullptr, nullptr, "csv");
     if (fileName.isEmpty()) {
         return;
     }

src/gui/KMessageWidget.cpp

@@ -411,7 +411,7 @@ void KMessageWidget::removeAction(QAction *action)
 
 void KMessageWidget::animatedShow()
 {
-    if (!style()->styleHint(QStyle::SH_Widget_Animate, 0, this)) {
+    if (!style()->styleHint(QStyle::SH_Widget_Animate, nullptr, this)) {
         show();
         emit showAnimationFinished();
         return;
@@ -436,7 +436,7 @@ void KMessageWidget::animatedShow()
 
 void KMessageWidget::animatedHide()
 {
-    if (!style()->styleHint(QStyle::SH_Widget_Animate, 0, this)) {
+    if (!style()->styleHint(QStyle::SH_Widget_Animate, nullptr, this)) {
         hide();
         emit hideAnimationFinished();
         return;

src/gui/MessageWidget.h

@@ -28,7 +28,7 @@ class MessageWidget : public KMessageWidget
     Q_OBJECT
 
 public:
-    explicit MessageWidget(QWidget* parent = 0);
+    explicit MessageWidget(QWidget* parent = nullptr);
 
     int autoHideTimeout() const;
 

src/gui/SearchWidget.h

@@ -35,7 +35,7 @@ class SearchWidget : public QWidget
     Q_OBJECT
 
 public:
-    explicit SearchWidget(QWidget* parent = 0);
+    explicit SearchWidget(QWidget* parent = nullptr);
     ~SearchWidget();
 
     void connectSignals(SignalMultiplexer& mx);
@@ -55,7 +55,7 @@ signals:
     void enterPressed();
 
 public slots:
-    void databaseChanged(DatabaseWidget* dbWidget = 0);
+    void databaseChanged(DatabaseWidget* dbWidget = nullptr);
 
 private slots:
     void startSearchTimer();

src/gui/entry/EditEntryWidget.cpp

@@ -1269,13 +1269,13 @@ QMenu* EditEntryWidget::createPresetsMenu()
     QMenu* expirePresetsMenu = new QMenu(this);
     expirePresetsMenu->addAction(tr("Tomorrow"))->setData(QVariant::fromValue(TimeDelta::fromDays(1)));
     expirePresetsMenu->addSeparator();
-    expirePresetsMenu->addAction(tr("%n week(s)", 0, 1))->setData(QVariant::fromValue(TimeDelta::fromDays(7)));
+    expirePresetsMenu->addAction(tr("%n week(s)", nullptr, 1))->setData(QVariant::fromValue(TimeDelta::fromDays(7)));
-    expirePresetsMenu->addAction(tr("%n week(s)", 0, 2))->setData(QVariant::fromValue(TimeDelta::fromDays(14)));
+    expirePresetsMenu->addAction(tr("%n week(s)", nullptr, 2))->setData(QVariant::fromValue(TimeDelta::fromDays(14)));
-    expirePresetsMenu->addAction(tr("%n week(s)", 0, 3))->setData(QVariant::fromValue(TimeDelta::fromDays(21)));
+    expirePresetsMenu->addAction(tr("%n week(s)", nullptr, 3))->setData(QVariant::fromValue(TimeDelta::fromDays(21)));
     expirePresetsMenu->addSeparator();
-    expirePresetsMenu->addAction(tr("%n month(s)", 0, 1))->setData(QVariant::fromValue(TimeDelta::fromMonths(1)));
+    expirePresetsMenu->addAction(tr("%n month(s)", nullptr, 1))->setData(QVariant::fromValue(TimeDelta::fromMonths(1)));
-    expirePresetsMenu->addAction(tr("%n month(s)", 0, 3))->setData(QVariant::fromValue(TimeDelta::fromMonths(3)));
+    expirePresetsMenu->addAction(tr("%n month(s)", nullptr, 3))->setData(QVariant::fromValue(TimeDelta::fromMonths(3)));
-    expirePresetsMenu->addAction(tr("%n month(s)", 0, 6))->setData(QVariant::fromValue(TimeDelta::fromMonths(6)));
+    expirePresetsMenu->addAction(tr("%n month(s)", nullptr, 6))->setData(QVariant::fromValue(TimeDelta::fromMonths(6)));
     expirePresetsMenu->addSeparator();
     expirePresetsMenu->addAction(tr("%n year(s)", 0, 1))->setData(QVariant::fromValue(TimeDelta::fromYears(1)));
     expirePresetsMenu->addAction(tr("%n year(s)", 0, 2))->setData(QVariant::fromValue(TimeDelta::fromYears(2)));

src/gui/entry/EditEntryWidget_p.h

@@ -24,7 +24,7 @@
 class AttributesListView : public QListView
 {
 public:
-    explicit AttributesListView(QWidget* parent = 0)
+    explicit AttributesListView(QWidget* parent = nullptr)
         : QListView(parent)
     {
         setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Expanding);

src/gui/entry/EntryModel.cpp

@@ -331,7 +331,7 @@ QVariant EntryModel::headerData(int section, Qt::Orientation orientation, int ro
 
 Qt::DropActions EntryModel::supportedDropActions() const
 {
-    return 0;
+    return Qt::IgnoreAction;
 }
 
 Qt::DropActions EntryModel::supportedDragActions() const

src/keys/drivers/YubiKey.cpp

@@ -37,8 +37,8 @@
 #define m_ykds (static_cast<YK_STATUS*>(m_ykds_void))
 
 YubiKey::YubiKey()
-    : m_yk_void(NULL)
+    : m_yk_void(nullptr)
-    , m_ykds_void(NULL)
+    , m_ykds_void(nullptr)
     , m_mutex(QMutex::Recursive)
 {
 }
@@ -59,7 +59,7 @@ bool YubiKey::init()
     m_mutex.lock();
 
     // previously initialized
-    if (m_yk != NULL && m_ykds != NULL) {
+    if (m_yk != nullptr && m_ykds != nullptr) {
 
         if (yk_get_status(m_yk, m_ykds)) {
             // Still connected
@@ -78,15 +78,15 @@ bool YubiKey::init()
 
     // TODO: handle multiple attached hardware devices
     m_yk_void = static_cast<void*>(yk_open_first_key());
-    if (m_yk == NULL) {
+    if (m_yk == nullptr) {
         m_mutex.unlock();
         return false;
     }
 
     m_ykds_void = static_cast<void*>(ykds_alloc());
-    if (m_ykds == NULL) {
+    if (m_ykds == nullptr) {
         yk_close_key(m_yk);
-        m_yk_void = NULL;
+        m_yk_void = nullptr;
         m_mutex.unlock();
         return false;
     }
@@ -101,12 +101,12 @@ bool YubiKey::deinit()
 
     if (m_yk) {
         yk_close_key(m_yk);
-        m_yk_void = NULL;
+        m_yk_void = nullptr;
     }
 
     if (m_ykds) {
         ykds_free(m_ykds);
-        m_ykds_void = NULL;
+        m_ykds_void = nullptr;
     }
 
     m_mutex.unlock();

src/streams/qtiocompressor.cpp

@@ -116,7 +116,7 @@ QtIOCompressorPrivate::~QtIOCompressorPrivate()
 void QtIOCompressorPrivate::flushZlib(int flushMode)
 {
     // No input.
-    zlibStream.next_in = 0;
+    zlibStream.next_in = nullptr;
     zlibStream.avail_in = 0;
     int status;
     do {
@@ -387,7 +387,7 @@ bool QtIOCompressor::open(OpenMode mode)
     if (read) {
         d->state = QtIOCompressorPrivate::NotReadFirstByte;
         d->zlibStream.avail_in = 0;
-        d->zlibStream.next_in = 0;
+        d->zlibStream.next_in = nullptr;
         if (d->streamFormat == QtIOCompressor::ZlibFormat) {
             status = inflateInit(&d->zlibStream);
         } else {