From bbe7e8a45a463adbd210856bd18b50604869bf5e Mon Sep 17 00:00:00 2001
From: Jonathan White <support@dmapps.us>
Date: Sat, 20 Apr 2019 12:00:45 -0400
Subject: [PATCH] Use QLocale for translation search instead of custom method
 (#3035)

Use built-in facilities of Qt to traverse QLocale::uiLanguages() to find a valid "most preferred"
language, but still respect user's choice in the application settings.
Fixes #3030. Fixes #1924.
---
 src/core/Translator.cpp | 27 ++++++++++++++-------------
 src/core/Translator.h   |  5 +++--
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/core/Translator.cpp b/src/core/Translator.cpp
index 595dadfa1..95de3ce91 100644
--- a/src/core/Translator.cpp
+++ b/src/core/Translator.cpp
@@ -34,13 +34,14 @@
  */
 void Translator::installTranslators()
 {
+    QLocale locale;
     QString language = config()->get("GUI/Language").toString();
-    if (language == "system" || language.isEmpty()) {
-        language = QLocale::system().name();
-    }
-    if (language == "en") {
+    if (!language.isEmpty() && language != "system") {
         // use actual English translation instead of the English locale source language
-        language = "en_US";
+        if (language == "en") {
+            language = "en_US";
+        }
+        locale = QLocale(language);
     }
 
     const QStringList paths = {
@@ -51,11 +52,12 @@ void Translator::installTranslators()
 
     bool translationsLoaded = false;
     for (const QString& path : paths) {
-        translationsLoaded |= installTranslator(language, path) || installTranslator("en_US", path);
+        translationsLoaded |= installTranslator(locale, path) || installTranslator(QLocale("en_US"), path);
         if (!installQtTranslator(language, path)) {
-            installQtTranslator("en", path);
+            installQtTranslator(QLocale("en"), path);
         }
     }
+
     if (!translationsLoaded) {
         // couldn't load configured language or fallback
         qWarning("Couldn't load translations.");
@@ -114,10 +116,10 @@ QList<QPair<QString, QString>> Translator::availableLanguages()
  * @param path local search path
  * @return true on success
  */
-bool Translator::installTranslator(const QString& language, const QString& path)
+bool Translator::installTranslator(const QLocale& locale, const QString& path)
 {
     QScopedPointer<QTranslator> translator(new QTranslator(qApp));
-    if (translator->load(QString("keepassx_%1").arg(language), path)) {
+    if (translator->load(locale, "keepassx_", "", path)) {
         return QCoreApplication::installTranslator(translator.take());
     }
     return false;
@@ -131,13 +133,12 @@ bool Translator::installTranslator(const QString& language, const QString& path)
  * @param path local search path
  * @return true on success
  */
-bool Translator::installQtTranslator(const QString& language, const QString& path)
+bool Translator::installQtTranslator(const QLocale& locale, const QString& path)
 {
     QScopedPointer<QTranslator> qtTranslator(new QTranslator(qApp));
-    if (qtTranslator->load(QString("qtbase_%1").arg(language), path)) {
+    if (qtTranslator->load(locale, "qtbase_", "", path)) {
         return QCoreApplication::installTranslator(qtTranslator.take());
-    } else if (qtTranslator->load(QString("qtbase_%1").arg(language),
-                                  QLibraryInfo::location(QLibraryInfo::TranslationsPath))) {
+    } else if (qtTranslator->load(locale, "qtbase_", "", QLibraryInfo::location(QLibraryInfo::TranslationsPath))) {
         return QCoreApplication::installTranslator(qtTranslator.take());
     }
     return false;
diff --git a/src/core/Translator.h b/src/core/Translator.h
index cf62f48e4..cfc49d710 100644
--- a/src/core/Translator.h
+++ b/src/core/Translator.h
@@ -20,6 +20,7 @@
 
 #include <QPair>
 #include <QString>
+#include <QLocale>
 
 class Translator
 {
@@ -28,8 +29,8 @@ public:
     static QList<QPair<QString, QString>> availableLanguages();
 
 private:
-    static bool installTranslator(const QString& language, const QString& path);
-    static bool installQtTranslator(const QString& language, const QString& path);
+    static bool installTranslator(const QLocale& locale, const QString& path);
+    static bool installQtTranslator(const QLocale& locale, const QString& path);
 };
 
 #endif // KEEPASSX_TRANSLATOR_H