fix: Settings, add a new private cleanScreenName method to update the screenName

Fixes: #9156
Names: contain only A-Z a-z 0-9 or - or . or _
       replace any spaces with _
       are < 256 characters in length
       can not start or end with - _ or .
Set a screen name if the settings does not have one do this instead of returning a default value

src/lib/common/Settings.cpp

@@ -33,6 +33,8 @@ void Settings::setSettingsFile(const QString &settingsFile)
   instance()->m_settings = new QSettings(settingsFile, QSettings::IniFormat, instance());
   instance()->m_settingsProxy->load(settingsFile);
   qInfo().noquote() << "settings file changed:" << instance()->m_settings->fileName();
+
+  instance()->setupScreenName();
 }
 
 void Settings::setStateFile(const QString &stateFile)
@@ -80,6 +82,8 @@ Settings::Settings(QObject *parent) : QObject(parent)
   const auto stateFile = QStringLiteral("%1/%2.state").arg(stateBase, kAppName);
 
   m_stateSettings = new QSettings(stateFile, QSettings::IniFormat, this);
+
+  setupScreenName();
 }
 
 void Settings::cleanSettings()
@@ -104,6 +108,35 @@ void Settings::cleanStateSettings()
   }
 }
 
+void Settings::setupScreenName()
+{
+  if (m_settings->value(Settings::Core::ScreenName).isNull())
+    m_settings->setValue(Settings::Core::ScreenName, cleanScreenName(QSysInfo::machineHostName()));
+}
+
+QString Settings::cleanScreenName(const QString &name)
+{
+  static const auto hyphen = QStringLiteral("-");
+  static const auto space = QStringLiteral(" ");
+  static const auto underscore = QStringLiteral("_");
+  static const auto peroid = QStringLiteral(".");
+  static const auto nothing = QStringLiteral("");
+  static const auto nameRegex = QRegularExpression(QStringLiteral("[^\\w\\-\\.]"));
+
+  QString cleanName = name.simplified();
+  cleanName.replace(space, underscore);
+  cleanName.replace(nameRegex, nothing);
+  while (cleanName.startsWith(hyphen) || cleanName.startsWith(underscore) || cleanName.startsWith(peroid))
+    cleanName.removeFirst();
+  while (cleanName.endsWith(hyphen) || cleanName.endsWith(underscore) || cleanName.endsWith(peroid))
+    cleanName.removeLast();
+  if (cleanName.length() > 255) {
+    cleanName.truncate(255);
+    cleanName = cleanScreenName(cleanName);
+  }
+  return cleanName;
+}
+
 int Settings::logLevelToInt(const QString &level)
 {
   // Can do this better later ?
@@ -152,15 +185,6 @@ QVariant Settings::defaultValue(const QString &key)
     return true;
   }
 
-  if (key == Core::ScreenName) {
-    // The localhost name can contain spaces and non word characters
-    QString name = QSysInfo::machineHostName().simplified();
-    name.replace(QLatin1String(" "), QStringLiteral("_"));
-    static const auto nameRegex = QRegularExpression(QLatin1String("\\W"));
-    name.replace(nameRegex, QLatin1String(""));
-    return name;
-  }
-
   if (key == Gui::WindowGeometry)
     return QRect();
 
@@ -287,8 +311,12 @@ void Settings::setValue(const QString &key, const QVariant &value)
 
   if (!value.isValid())
     settings->remove(key);
-  else
+  else {
-    settings->setValue(key, value);
+    if (key == Settings::Core::ScreenName)
+      settings->setValue(key, cleanScreenName(value.toString()));
+    else
+      settings->setValue(key, value);
+  }
 
   settings->sync();
   Q_EMIT instance()->settingsChanged(key);

src/lib/common/Settings.h

@@ -149,6 +149,18 @@ private:
   void cleanSettings();
   void cleanStateSettings();
 
+  /**
+   * @brief write an initial screen name
+   */
+  void setupScreenName();
+
+  /**
+   * @brief cleanScreenName ensure a valid screenName from the provided one
+   * @param name any string to be used as the screenName
+   * @return a valid screeName
+   */
+  static QString cleanScreenName(const QString &name);
+
   QSettings *m_settings = nullptr;
   QSettings *m_stateSettings = nullptr;
   std::shared_ptr<QSettingsProxy> m_settingsProxy;

src/unittests/common/SettingsTests.cpp

@@ -61,7 +61,8 @@ void SettingsTests::checkValidSettings()
   QSignalSpy spy(Settings::instance(), &Settings::settingsChanged);
   QVERIFY(spy.isValid());
 
-  const auto validKeys = Settings::validKeys();
+  const auto keysToCheck = QRegularExpression(QLatin1String("[^%1]").arg(Settings::Core::ScreenName));
+  const auto validKeys = Settings::validKeys().filter(keysToCheck);
   for (const auto &setting : validKeys) {
     const auto value = Settings::value(setting).toString();
     QCOMPARE(Settings::defaultValue(setting).toString(), value);
@@ -81,4 +82,28 @@ void SettingsTests::checkValidSettings()
   }
 }
 
+void SettingsTests::checkCleanScreenName()
+{
+  const auto input = QStringLiteral("--!_ _-S@c#r$e%e^&*(n)= +Name\n[1]2|3?4--5>6<,7`~/8*90\\.lan--..    ..");
+  const auto expected = QStringLiteral("Screen_Name_1234--567890.lan");
+
+  Settings::setValue(Settings::Core::ScreenName, input);
+
+  QCOMPARE(Settings::value(Settings::Core::ScreenName).toString(), expected);
+}
+
+void SettingsTests::checkCleanScreenName_LongName()
+{
+  QString input;
+  input.fill('f', 300);
+  input.prepend('.');
+
+  QString expected;
+  expected.fill('f', 255);
+
+  Settings::setValue(Settings::Core::ScreenName, input);
+
+  QCOMPARE(Settings::value(Settings::Core::ScreenName).toString(), expected);
+}
+
 QTEST_MAIN(SettingsTests)

src/unittests/common/SettingsTests.h

@@ -23,6 +23,8 @@ private Q_SLOTS:
   void tlsTrustedServersDb();
   void tlsTrustedClientsDb();
   void checkValidSettings();
+  void checkCleanScreenName();
+  void checkCleanScreenName_LongName();
 
 private:
   inline static const QString m_settingsPathTemp = QStringLiteral("tmp/test");