Replace Google with DuckDuckGo for optional fallback favicon fetch URL

Modify the work initially done in keepassxreboot#36, and most recently modified in keepassxreboot#1786,
to use DuckDuckGo's https://icons.duckduckgo.com/ip3/www.example.com.ico
favicon endpoint.

Fixes keepassxreboot#2258

src/core/Config.cpp

@@ -148,7 +148,7 @@ void Config::init(const QString& fileName)
     m_defaults.insert("security/passwordscleartext", false);
     m_defaults.insert("security/hidepassworddetails", true);
     m_defaults.insert("security/autotypeask", true);
-    m_defaults.insert("security/IconDownloadFallbackToGoogle", false);
+    m_defaults.insert("security/IconDownloadFallbackToDuckDuckGo", false);
     m_defaults.insert("security/resettouchid", false);
     m_defaults.insert("security/resettouchidtimeout", 30);
     m_defaults.insert("security/resettouchidscreenlock", true);

src/gui/EditWidgetIcons.cpp

@@ -219,12 +219,12 @@ void EditWidgetIcons::downloadFavicon()
     }
     m_urlsToTry.append(QUrl(m_url.scheme() + "://" + secondLevelDomain + "/favicon.ico"));
 
-    // Try to use Google fallback, if enabled
-    if (config()->get("security/IconDownloadFallbackToGoogle", false).toBool()) {
-        QUrl urlGoogle = QUrl("https://www.google.com/s2/favicons");
+    // Try to use DuckDuckGo fallback, if enabled
+    if (config()->get("security/IconDownloadFallbackToDuckDuckGo", false).toBool()) {
+        QUrl urlDuckDuckGo = QUrl("https://icons.duckduckgo.com");
 
-        urlGoogle.setQuery("domain=" + QUrl::toPercentEncoding(secondLevelDomain));
-        m_urlsToTry.append(urlGoogle);
+        urlDuckDuckGo.setPath("/ip3/" + QUrl::toPercentEncoding(fullyQualifiedDomain) + ".ico");
+        m_urlsToTry.append(urlDuckDuckGo);
     }
 
     startFetchFavicon(m_urlsToTry.takeFirst());
@@ -242,7 +242,7 @@ void EditWidgetIcons::fetchFinished()
 {
 #ifdef WITH_XC_NETWORKING
     QImage image;
-    bool googleFallbackEnabled = config()->get("security/IconDownloadFallbackToGoogle", false).toBool();
+    bool duckDuckGoFallbackEnabled = config()->get("security/IconDownloadFallbackToDuckDuckGo", false).toBool();
     bool error = (m_reply->error() != QNetworkReply::NoError);
     QUrl redirectTarget = getRedirectTarget(m_reply);
 
@@ -275,9 +275,9 @@ void EditWidgetIcons::fetchFinished()
         startFetchFavicon(m_urlsToTry.takeFirst());
         return;
     } else {
-        if (!googleFallbackEnabled) {
+        if (!duckDuckGoFallbackEnabled) {
             emit messageEditEntry(tr("Unable to fetch favicon.") + "\n" +
-                                  tr("Hint: You can enable Google as a fallback under Tools>Settings>Security"),
+                                  tr("Hint: You can enable DuckDuckGo as a fallback under Tools>Settings>Security"),
                                   MessageWidget::Error);
         } else {
             emit messageEditEntry(tr("Unable to fetch favicon."), MessageWidget::Error);

src/gui/SettingsWidget.cpp

@@ -186,7 +186,7 @@ void SettingsWidget::loadSettings()
     m_secUi->lockDatabaseMinimizeCheckBox->setChecked(config()->get("security/lockdatabaseminimize").toBool());
     m_secUi->lockDatabaseOnScreenLockCheckBox->setChecked(config()->get("security/lockdatabasescreenlock").toBool());
     m_secUi->relockDatabaseAutoTypeCheckBox->setChecked(config()->get("security/relockautotype").toBool());
-    m_secUi->fallbackToGoogle->setChecked(config()->get("security/IconDownloadFallbackToGoogle").toBool());
+    m_secUi->fallbackToDuckDuckGo->setChecked(config()->get("security/IconDownloadFallbackToDuckDuckGo").toBool());
 
     m_secUi->passwordCleartextCheckBox->setChecked(config()->get("security/passwordscleartext").toBool());
     m_secUi->passwordDetailsCleartextCheckBox->setChecked(config()->get("security/hidepassworddetails").toBool());
@@ -256,7 +256,7 @@ void SettingsWidget::saveSettings()
     config()->set("security/lockdatabaseminimize", m_secUi->lockDatabaseMinimizeCheckBox->isChecked());
     config()->set("security/lockdatabasescreenlock", m_secUi->lockDatabaseOnScreenLockCheckBox->isChecked());
     config()->set("security/relockautotype", m_secUi->relockDatabaseAutoTypeCheckBox->isChecked());
-    config()->set("security/IconDownloadFallbackToGoogle", m_secUi->fallbackToGoogle->isChecked());
+    config()->set("security/IconDownloadFallbackToDuckDuckGo", m_secUi->fallbackToDuckDuckGo->isChecked());
 
     config()->set("security/passwordscleartext", m_secUi->passwordCleartextCheckBox->isChecked());
     config()->set("security/hidepassworddetails", m_secUi->passwordDetailsCleartextCheckBox->isChecked());

src/gui/SettingsWidgetSecurity.ui

@@ -203,9 +203,9 @@
      </property>
      <layout class="QVBoxLayout" name="verticalLayout_3">
       <item>
-       <widget class="QCheckBox" name="fallbackToGoogle">
+       <widget class="QCheckBox" name="fallbackToDuckDuckGo">
         <property name="text">
-         <string>Use Google as fallback for downloading website icons</string>
+         <string>Use DuckDuckGo as fallback for downloading website icons</string>
         </property>
        </widget>
       </item>