Add-ons localization support

Add-on meta-data can be localized now, in the same manner as aircraft
metadata.

src/Add-ons/Addon.cxx

@@ -469,6 +469,14 @@ Addon::readMenubarItems(const SGPath& menuFile)
   return res;
 }
 
+void Addon::retranslate()
+{
+    Addon::Metadata metadata = MetadataParser::parseMetadataFile(_basePath);
+    setName(std::move(metadata.name));
+    setShortDescription(std::move(metadata.shortDescription));
+    setLongDescription(std::move(metadata.longDescription));
+}
+
 // Static method
 void Addon::setupGhost(nasal::Hash& addonsModule)
 {

src/Add-ons/Addon.hxx

@@ -195,7 +195,12 @@ public:
 
   static void setupGhost(nasal::Hash& addonsModule);
 
-private:
+  /**
+     * @brief update string values (description, etc) based on the active locale
+     */
+  void retranslate();
+
+  private:
   class Metadata;
   class MetadataParser;
 

src/Add-ons/AddonMetadataParser.cxx

@@ -35,6 +35,9 @@
 #include "exceptions.hxx"
 #include "pointer_traits.hxx"
 
+#include <Main/globals.hxx>
+#include <Main/locale.hxx>
+
 namespace strutils = simgear::strutils;
 
 using std::string;
@@ -53,6 +56,23 @@ Addon::MetadataParser::getMetadataFile(const SGPath& addonPath)
   return addonPath / "addon-metadata.xml";
 }
 
+static string getMaybeLocalized(const string& tag, SGPropertyNode* base, SGPropertyNode* lang)
+{
+    if (lang) {
+        auto n = lang->getChild(tag);
+        if (n) {
+            return strutils::strip(n->getStringValue());
+        }
+    }
+
+    auto n = base->getChild(tag);
+    if (n) {
+        return strutils::strip(n->getStringValue());
+    }
+
+    return {};
+}
+
 // Static method
 Addon::Metadata
 Addon::MetadataParser::parseMetadataFile(const SGPath& addonPath)
@@ -121,6 +141,9 @@ Addon::MetadataParser::parseMetadataFile(const SGPath& addonPath)
       metadataFile.utf8Str() + "'");
   }
 
+  SGPropertyNode* localizedNode = addonNode->getChild("localized");
+  SGPropertyNode* langStringsNode = globals->get_locale()->selectLanguageNode(localizedNode);
+
   SGPropertyNode *idNode = addonNode->getChild("identifier");
   if (idNode == nullptr) {
     throw errors::error_loading_metadata_file(
@@ -147,7 +170,8 @@ Addon::MetadataParser::parseMetadataFile(const SGPath& addonPath)
       "no /addon/name node found in add-on metadata file '" +
       metadataFile.utf8Str() + "'");
   }
-  metadata.name = strutils::strip(nameNode->getStringValue());
+
+  metadata.name = getMaybeLocalized("name", addonNode, langStringsNode);
 
   // Require a non-empty name for the add-on
   if (metadata.name.empty()) {
@@ -170,19 +194,8 @@ Addon::MetadataParser::parseMetadataFile(const SGPath& addonPath)
   metadata.maintainers = parseContactsNode<Maintainer>(
     metadataFile, addonNode->getChild("maintainers"));
 
-  SGPropertyNode *shortDescNode = addonNode->getChild("short-description");
+  metadata.shortDescription = getMaybeLocalized("short-description", addonNode, langStringsNode);
-  if (shortDescNode != nullptr) {
+  metadata.longDescription = getMaybeLocalized("long-description", addonNode, langStringsNode);
-    metadata.shortDescription = strutils::strip(shortDescNode->getStringValue());
-  } else {
-    metadata.shortDescription = string();
-  }
-
-  SGPropertyNode *longDescNode = addonNode->getChild("long-description");
-  if (longDescNode != nullptr) {
-    metadata.longDescription = strutils::strip(longDescNode->getStringValue());
-  } else {
-    metadata.longDescription = string();
-  }
 
   std::tie(metadata.licenseDesignation, metadata.licenseFile,
            metadata.licenseUrl) = parseLicenseNode(addonPath, addonNode);

src/GUI/CocoaHelpers.mm

@@ -194,7 +194,7 @@ QWindow* qtWindowFromOSG(osgViewer::GraphicsWindow* graphicsWindow)
     
 } // of namespace flightgear
 
-string_list FGLocale::getUserLanguage()
+string_list FGLocale::getUserLanguages()
 {
     CocoaAutoreleasePool ap;
     string_list result;

src/Main/locale.cxx

@@ -37,6 +37,8 @@
 #include "locale.hxx"
 #include "XLIFFParser.hxx"
 
+#include <Add-ons/AddonMetadataParser.hxx>
+
 using std::vector;
 using std::string;
 
@@ -67,11 +69,24 @@ string FGLocale::removeEncodingPart(const string& locale)
     return res;
 }
 
+string removeLocalePart(const string& locale)
+{
+    std::size_t pos = locale.find('_');
+    if (pos == string::npos) {
+        pos = locale.find('-');
+    }
+
+    if (pos == string::npos)
+        return {};
+
+    return locale.substr(0, pos);
+}
+
 #ifdef _WIN32
 
 
 string_list
-FGLocale::getUserLanguage()
+FGLocale::getUserLanguages()
 {
 	unsigned long bufSize = 128;
 	wchar_t* localeNameBuf = reinterpret_cast<wchar_t*>(alloca(bufSize));
@@ -119,7 +134,7 @@ FGLocale::getUserLanguage()
  * Determine locale/language settings on Linux/Unix.
  */
 string_list
-FGLocale::getUserLanguage()
+FGLocale::getUserLanguages()
 {
     string_list result;
     const char* langEnv = ::getenv("LANG");
@@ -171,9 +186,9 @@ FGLocale::findLocaleNode(const string& localeSpec)
         pos = language.find('-');
     }
 
-    if ((pos != string::npos) && (pos > 0))
+    const auto justTheLanguage = removeLocalePart(language);
-    {
+    if (!justTheLanguage.empty()) {
-        node = findLocaleNode(language.substr(0, pos));
+        node = findLocaleNode(justTheLanguage);
         if (node)
             return node;
     }
@@ -185,26 +200,26 @@ FGLocale::findLocaleNode(const string& localeSpec)
 // a default is determined matching the system locale.
 bool FGLocale::selectLanguage(const std::string& language)
 {
-    string_list languages = getUserLanguage();
+    _languages = getUserLanguages();
-    if (languages.empty()) {
+    if (_languages.empty()) {
         // Use plain C locale if nothing is available.
         SG_LOG(SG_GENERAL, SG_WARN, "Unable to detect system language" );
-        languages.push_back("C");
+        _languages.push_back("C");
     }
 
     // if we were passed a language option, try it first
     if (!language.empty()) {
-        languages.insert(languages.begin(), language);
+        _languages.insert(_languages.begin(), language);
     }
 
-    _currentLocaleString = removeEncodingPart(languages[0]);
+    _currentLocaleString = removeEncodingPart(_languages.front());
     if (_currentLocaleString == "C") {
         _currentLocaleString.clear();
     }
 
     _currentLocale = nullptr;
 
-    for (const string& lang: languages) {
+    for (const string& lang : _languages) {
         SG_LOG(SG_GENERAL, SG_DEBUG,
                "Trying to find locale for '" << lang << "'");
         _currentLocale = findLocaleNode(lang);
@@ -216,7 +231,7 @@ bool FGLocale::selectLanguage(const std::string& language)
             break;
         }
     }
-    
+
     if (_currentLocale && _currentLocale->hasChild("xliff")) {
         parseXLIFF(_currentLocale);
     }
@@ -242,6 +257,7 @@ void FGLocale::clear()
 {
     _inited = false;
     _currentLocaleString.clear();
+    _languages.clear();
 
     if (_currentLocale && (_currentLocale != _defaultLocale)) {
         // remove loaded strings, so we don't duplicate
@@ -585,3 +601,23 @@ std::string fgTrPrintfMsg(const char* key, ...)
     va_end(args);
     return r;
 }
+
+SGPropertyNode_ptr FGLocale::selectLanguageNode(SGPropertyNode* langs) const
+{
+    if (!langs)
+        return {};
+
+    for (auto l : _languages) {
+        const auto langNoEncoding = removeEncodingPart(l);
+        if (langs->hasChild(langNoEncoding)) {
+            return langs->getChild(langNoEncoding);
+        }
+
+        const auto justLang = removeLocalePart(langNoEncoding);
+        if (langs->hasChild(justLang)) {
+            return langs->getChild(justLang);
+        }
+    }
+
+    return {};
+}

src/Main/locale.hxx

@@ -118,6 +118,12 @@ public:
      */
     void clear();
 
+    /**
+        @ brief given a node with children corresponding to different language / locale codes,
+        select one based on the user preferred langauge
+     */
+    SGPropertyNode_ptr selectLanguageNode(SGPropertyNode* langs) const;
+
 protected:
     /**
      * Find property node matching given language.
@@ -142,7 +148,7 @@ protected:
     /**
      * Obtain user's default language setting.
      */
-    string_list getUserLanguage();
+    string_list getUserLanguages();
 
     SGPropertyNode_ptr _intl;
     SGPropertyNode_ptr _currentLocale;
@@ -161,6 +167,11 @@ private:
      */
     static std::string removeEncodingPart(const std::string& locale);
 
+    // this is the ordered list of languages to try. It's the same as
+    // returned by getUserLanguages except if the user has used --langauge to
+    // override, that will be the first item.
+
+    string_list _languages;
     bool _inited = false;
 };