Added initial localization support

.gitignore

@@ -1,6 +1,7 @@
 # Object files
 *.o
 *.lo
+*.mo
 *.slo
 
 # Shared libraries

CMake/Packages/FindIntl.cmake

@@ -0,0 +1,60 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindIntl
+--------
+
+Find the Gettext libintl headers and libraries.
+
+This module reports information about the Gettext libintl
+installation in several variables.  General variables::
+
+  Intl_FOUND - true if the libintl headers and libraries were found
+  Intl_INCLUDE_DIRS - the directory containing the libintl headers
+  Intl_LIBRARIES - libintl libraries to be linked
+
+The following cache variables may also be set::
+
+  Intl_INCLUDE_DIR - the directory containing the libintl headers
+  Intl_LIBRARY - the libintl library (if any)
+
+.. note::
+  On some platforms, such as Linux with GNU libc, the gettext
+  functions are present in the C standard library and libintl
+  is not required.  ``Intl_LIBRARIES`` will be empty in this
+  case.
+
+.. note::
+  If you wish to use the Gettext tools (``msgmerge``,
+  ``msgfmt``, etc.), use :module:`FindGettext`.
+#]=======================================================================]
+
+
+# Written by Roger Leigh <rleigh@codelibre.net>
+
+# Find include directory
+find_path(Intl_INCLUDE_DIR
+          NAMES "libintl.h"
+          DOC "libintl include directory")
+mark_as_advanced(Intl_INCLUDE_DIR)
+
+# Find all Intl libraries
+find_library(Intl_LIBRARY "intl"
+  DOC "libintl libraries (if not in the C library)")
+mark_as_advanced(Intl_LIBRARY)
+
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Intl
+                                  FOUND_VAR Intl_FOUND
+                                  REQUIRED_VARS Intl_INCLUDE_DIR
+                                  FAIL_MESSAGE "Failed to find Gettext libintl")
+
+if(Intl_FOUND)
+  set(Intl_INCLUDE_DIRS "${Intl_INCLUDE_DIR}")
+  if(Intl_LIBRARY)
+    set(Intl_LIBRARIES "${Intl_LIBRARY}")
+  else()
+    unset(Intl_LIBRARIES)
+  endif()
+endif()

CMakeLists.txt

@@ -136,6 +136,7 @@ elseif(NOT EMSCRIPTEN AND NOT ANDROID)
     find_package(FFmpeg REQUIRED)
     find_package(FreeImage REQUIRED)
     find_package(Freetype REQUIRED)
+    find_package(Intl REQUIRED)
     find_package(Libgit2 REQUIRED)
     find_package(Pugixml REQUIRED)
     find_package(SDL2 REQUIRED)

es-app/src/guis/GuiMenu.cpp

@@ -36,6 +36,7 @@
 #include "guis/GuiTextEditKeyboardPopup.h"
 #include "guis/GuiTextEditPopup.h"
 #include "guis/GuiThemeDownloader.h"
+#include "utils/LocalizationUtil.h"
 #include "utils/PlatformUtil.h"
 
 #if defined(__ANDROID__)
@@ -48,7 +49,7 @@
 
 GuiMenu::GuiMenu()
     : mRenderer {Renderer::getInstance()}
-    , mMenu {"MAIN MENU"}
+    , mMenu {_("MAIN MENU")}
     , mThemeDownloaderReloadCounter {0}
 {
     const bool isFullUI {UIModeController::getInstance()->isUIModeFull()};

es-app/src/main.cpp

@@ -29,6 +29,7 @@
 #include "guis/GuiDetectDevice.h"
 #include "guis/GuiLaunchScreen.h"
 #include "utils/FileSystemUtil.h"
+#include "utils/LocalizationUtil.h"
 #include "utils/PlatformUtil.h"
 #include "utils/StringUtil.h"
 #include "views/ViewController.h"
@@ -732,6 +733,7 @@ int main(int argc, char* argv[])
         return 0;
     }
 
+    Utils::Localization::setLanguage(Utils::Localization::getLocale());
     Scripting::fireEvent("startup");
 
 #if defined(__EMSCRIPTEN__)

es-core/CMakeLists.txt

@@ -90,6 +90,7 @@ set(CORE_HEADERS
     # Utils
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/CImgUtil.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/FileSystemUtil.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/LocalizationUtil.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/MathUtil.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/PlatformUtil.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/StringUtil.h
@@ -164,6 +165,7 @@ set(CORE_SOURCES
     # Utils
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/CImgUtil.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/FileSystemUtil.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/LocalizationUtil.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/MathUtil.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/PlatformUtil.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/utils/StringUtil.cpp

es-core/src/utils/LocalizationUtil.cpp

@@ -0,0 +1,92 @@
+//  SPDX-License-Identifier: MIT
+//
+//  ES-DE Frontend
+//  LocalizationUtil.cpp
+//
+//  Localization functions.
+//  Provides support for translations using gettext/libintl.
+//
+
+#include "utils/LocalizationUtil.h"
+
+#include "Log.h"
+#include "resources/ResourceManager.h"
+#include "utils/StringUtil.h"
+
+#include <algorithm>
+#include <iostream>
+
+namespace Utils
+{
+    namespace Localization
+    {
+        std::string getLocale()
+        {
+            std::string language;
+
+            // The LANGUAGE environment variable takes precedence over LANG.
+            if (getenv("LANGUAGE") != nullptr)
+                language = getenv("LANGUAGE");
+
+            const std::vector<std::string> languageValues {
+                Utils::String::delimitedStringToVector(language, ":")};
+
+            for (auto value : languageValues) {
+                if (std::find(sSupportedLanguages.cbegin(), sSupportedLanguages.cend(), value) !=
+                    sSupportedLanguages.cend()) {
+                    return value;
+                }
+            }
+
+            if (getenv("LANG") != nullptr)
+                language = getenv("LANG");
+
+            if (language.empty())
+                return "en_US";
+
+            return language.substr(0, language.find("."));
+        }
+
+        void setLanguage(const std::string& locale)
+        {
+            if (std::find(sSupportedLanguages.cbegin(), sSupportedLanguages.cend(), locale) ==
+                sSupportedLanguages.cend()) {
+                LOG(LogInfo) << "No support for language \"" << locale
+                             << "\", reverting to default language \"en_US\"";
+                return;
+            }
+            else {
+                LOG(LogInfo) << "Setting application language to \"" << locale << "\"";
+            }
+
+            // No need to perform translations if we're using the default language.
+            if (locale == "en_US")
+                return;
+
+            std::string localePath;
+            localePath.append("/")
+                .append(locale)
+                .append("/LC_MESSAGES/")
+                .append(locale)
+                .append(".mo");
+
+            // If the message catalog file is not found then an emergency shutdown will be
+            // initiated by ResourceManager.
+            std::string objectPath {
+                ResourceManager::getInstance().getResourcePath(":/locale" + localePath)};
+
+            // This makes it possible to override the message catalog with a file in the
+            // application data directory.
+            if (objectPath.length() > localePath.length())
+                objectPath = objectPath.substr(0, objectPath.length() - localePath.length());
+
+            setenv("LANGUAGE", locale.c_str(), 1);
+            setlocale(LC_MESSAGES, "");
+            textdomain(locale.c_str());
+            bindtextdomain(locale.c_str(), objectPath.c_str());
+            bind_textdomain_codeset(locale.c_str(), "UTF-8");
+        }
+
+    } // namespace Localization
+
+} // namespace Utils

es-core/src/utils/LocalizationUtil.h

@@ -0,0 +1,32 @@
+//  SPDX-License-Identifier: MIT
+//
+//  ES-DE Frontend
+//  LocalizationUtil.h
+//
+//  Localization functions.
+//  Provides support for translations using gettext/libintl.
+//
+
+#ifndef ES_CORE_UTILS_LOCALIZATION_UTIL_H
+#define ES_CORE_UTILS_LOCALIZATION_UTIL_H
+
+#include <libintl.h>
+#include <string>
+#include <vector>
+
+#define _(STR) std::string(gettext(STR))
+
+namespace Utils
+{
+    namespace Localization
+    {
+        static inline std::vector<std::string> sSupportedLanguages {"en_US", "sv_SE"};
+
+        std::string getLocale();
+        void setLanguage(const std::string& locale);
+
+    } // namespace Localization
+
+} // namespace Utils
+
+#endif // ES_CORE_UTILS_LOCALIZATION_UTIL_H