Merge branch 'multi-fallback-langs'

Closes https://github.com/wxWidgets/wxWidgets/pull/1006

include/wx/translation.h

@@ -145,6 +145,12 @@ public:
     wxString GetBestTranslation(const wxString& domain,
                                 const wxString& msgIdLanguage = "en");
 
+    // find best and all other suitable translation languages for given domain
+    wxArrayString GetAcceptableTranslations(const wxString& domain,
+                                            wxLanguage msgIdLanguage);
+    wxArrayString GetAcceptableTranslations(const wxString& domain,
+                                            const wxString& msgIdLanguage = "en");
+
     // add standard wxWidgets catalog ("wxstd")
     bool AddStdCatalog();
 

interface/wx/translation.h

@@ -137,6 +137,34 @@ public:
                                 const wxString& msgIdLanguage = "en");
 
     /**
+        Returns the languages of all translations that can be used for the @a
+        domain.
+
+        This is a more general version of GetBestTranslation(), which returns
+        the whole list of preferred UI languages for which a translation for
+        the @a domain was found instead of just the first, i.e. the most
+        preferred, element of this list.
+
+        @param domain
+            The catalog domain to look for.
+
+        @param msgIdLanguage
+            Specifies the language of "msgid" strings in source code (i.e.
+            arguments to GetString(), wxGetTranslation() and the _() macro).
+
+        @return An array of language codes if any suitable matches were found,
+            empty array otherwise.
+
+        @since 3.1.2
+     */
+    wxArrayString GetAcceptableTranslations(const wxString& domain,
+                                            wxLanguage msgIdLanguage);
+
+    /// @overload
+    wxArrayString GetAcceptableTranslations(const wxString& domain,
+                                            const wxString& msgIdLanguage = "en");
+
+        /**
         Add standard wxWidgets catalogs ("wxstd" and possible port-specific
         catalogs).
 
@@ -147,9 +175,10 @@ public:
     bool AddStdCatalog();
 
     /**
-        Add a catalog for use with the current locale.
+        Add a catalog for the preferred UI language. In case of multiple
+        preferences, add catalog for each language, if available.
 
-        By default, it is searched for in standard places (see
+        By default, the catalog is searched for in standard places (see
         wxFileTranslationsLoader), but you may also prepend additional
         directories to the search path with
         wxFileTranslationsLoader::AddCatalogLookupPathPrefix().
@@ -173,8 +202,9 @@ public:
             code are used instead.
 
         @return
-            @true if catalog was successfully loaded, @false otherwise (which might
+            @true if catalog in the most preferred language was successfully loaded,
-            mean that the catalog is not found or that it isn't in the correct format).
+            @false otherwise (which might mean that the catalog is not found or that
+            it isn't in the correct format).
      */
     bool AddCatalog(const wxString& domain,
                     wxLanguage msgIdLanguage = wxLANGUAGE_ENGLISH_US);
@@ -200,8 +230,9 @@ public:
             in case they use 8-bit characters (e.g. German or French strings).
 
         @return
-            @true if catalog was successfully loaded, @false otherwise (which might
+            @true if catalog in the most preferred language was successfully loaded,
-            mean that the catalog is not found or that it isn't in the correct format).
+            @false otherwise (which might mean that the catalog is not found or that
+            it isn't in the correct format).
      */
     bool AddCatalog(const wxString& domain,
                     wxLanguage msgIdLanguage,

src/common/translation.cpp

@@ -127,7 +127,7 @@ wxString GetPreferredUILanguageFallback(const wxArrayString& WXUNUSED(available)
 
 #ifdef __WINDOWS__
 
-wxString GetPreferredUILanguage(const wxArrayString& available)
+wxString GetPreferredUILanguage(const wxArrayString& available, wxArrayString& allPreferred)
 {
     typedef BOOL (WINAPI *GetUserPreferredUILanguages_t)(DWORD, PULONG, PWSTR, PULONG);
     static GetUserPreferredUILanguages_t s_pfnGetUserPreferredUILanguages = NULL;
@@ -172,18 +172,20 @@ wxString GetPreferredUILanguage(const wxArrayString& available)
                     wxString lang(*j);
                     lang.Replace("-", "_");
                     if ( available.Index(lang, /*bCase=*/false) != wxNOT_FOUND )
-                        return lang;
+                        allPreferred.Add(lang);
                     size_t pos = lang.find('_');
                     if ( pos != wxString::npos )
                     {
                         lang = lang.substr(0, pos);
                         if ( available.Index(lang, /*bCase=*/false) != wxNOT_FOUND )
-                            return lang;
+                            allPreferred.Add(lang);
                     }
                 }
             }
         }
     }
+    if ( !allPreferred.empty() )
+        return allPreferred[0];
 
     return GetPreferredUILanguageFallback(available);
 }
@@ -207,7 +209,7 @@ void LogTraceArray(const char *prefix, CFArrayRef arr)
 
 #endif // wxUSE_LOG_TRACE
 
-wxString GetPreferredUILanguage(const wxArrayString& available)
+wxString GetPreferredUILanguage(const wxArrayString& available, wxArrayString &allPreferred)
 {
     wxStringToStringHashMap availableNormalized;
     wxCFRef<CFMutableArrayRef> availableArr(
@@ -231,17 +233,19 @@ wxString GetPreferredUILanguage(const wxArrayString& available)
     LogTraceArray(" - system preferred languages", prefArr);
 
     unsigned prefArrLength = CFArrayGetCount(prefArr);
-    if ( prefArrLength > 0 )
+    for ( size_t x = 0; x < prefArrLength; ++x )
     {
         // Lookup the name in 'available' by index -- we need to get the
         // original value corresponding to the normalized one chosen.
-        wxString lang(wxCFStringRef::AsString((CFStringRef)CFArrayGetValueAtIndex(prefArr, 0)));
+        wxString lang(wxCFStringRef::AsString((CFStringRef)CFArrayGetValueAtIndex(prefArr, x)));
         wxStringToStringHashMap::const_iterator i = availableNormalized.find(lang);
         if ( i == availableNormalized.end() )
-            return lang;
+            allPreferred.push_back(lang);
         else
-            return i->second;
+            allPreferred.push_back(i->second);
     }
+    if ( allPreferred.empty() == false )
+        return allPreferred[0];
 
     return GetPreferredUILanguageFallback(available);
 }
@@ -255,7 +259,7 @@ wxString GetPreferredUILanguage(const wxArrayString& available)
 // The LANGUAGE variable may contain a colon separated list of language
 // codes in the order of preference.
 // http://www.gnu.org/software/gettext/manual/html_node/The-LANGUAGE-variable.html
-wxString GetPreferredUILanguage(const wxArrayString& available)
+wxString GetPreferredUILanguage(const wxArrayString& available, wxArrayString &allPreferred)
 {
     wxString languageFromEnv;
     wxArrayString preferred;
@@ -283,15 +287,17 @@ wxString GetPreferredUILanguage(const wxArrayString& available)
     {
         wxString lang(*j);
         if ( available.Index(lang) != wxNOT_FOUND )
-            return lang;
+            allPreferred.Add(lang);
         size_t pos = lang.find('_');
         if ( pos != wxString::npos )
         {
             lang = lang.substr(0, pos);
             if ( available.Index(lang) != wxNOT_FOUND )
-                return lang;
+                allPreferred.Add(lang);
         }
     }
+    if ( allPreferred.empty() == false )
+        return allPreferred[0];
 
     return GetPreferredUILanguageFallback(available);
 }
@@ -1549,9 +1555,9 @@ bool wxTranslations::AddCatalog(const wxString& domain,
                                 wxLanguage msgIdLanguage)
 {
     const wxString msgIdLang = wxLocale::GetLanguageCanonicalName(msgIdLanguage);
-    const wxString domain_lang = GetBestTranslation(domain, msgIdLang);
+    const wxArrayString domain_langs = GetAcceptableTranslations(domain, msgIdLanguage);
 
-    if ( domain_lang.empty() )
+    if ( domain_langs.empty() )
     {
         wxLogTrace(TRACE_I18N,
                     wxS("no suitable translation for domain '%s' found"),
@@ -1559,11 +1565,30 @@ bool wxTranslations::AddCatalog(const wxString& domain,
         return false;
     }
 
-    wxLogTrace(TRACE_I18N,
+    bool success = false;
-                wxS("adding '%s' translation for domain '%s' (msgid language '%s')"),
+    for ( wxArrayString::const_iterator lang = domain_langs.begin();
-                domain_lang, domain, msgIdLang);
+          lang != domain_langs.end();
+          ++lang )
+    {
+        wxLogTrace(TRACE_I18N,
+                   wxS("adding '%s' translation for domain '%s' (msgid language '%s')"),
+                   *lang, domain, msgIdLang);
 
-    return LoadCatalog(domain, domain_lang, msgIdLang);
+        // No use loading languages that are less preferred than the
+        // msgid language, as by definition it contains all the strings
+        // in the msgid language.
+        if ( msgIdLang == *lang )
+            break;
+
+        // We determine success by the success of loading/failing to load
+        // the most preferred (i.e. the first one) language's catalog:
+        if ( lang == domain_langs.begin() )
+            success = LoadCatalog(domain, *lang, msgIdLang);
+        else
+            LoadCatalog(domain, *lang, msgIdLang);
+    }
+
+    return success;
 }
 
 
@@ -1650,20 +1675,37 @@ wxString wxTranslations::GetBestTranslation(const wxString& domain,
 wxString wxTranslations::GetBestTranslation(const wxString& domain,
                                             const wxString& msgIdLanguage)
 {
-    // explicitly set language should always be respected
+    const wxArrayString allGoodOnes = GetAcceptableTranslations(domain, msgIdLanguage);
-    if ( !m_lang.empty() )
-        return m_lang;
 
+    wxLogTrace(TRACE_I18N, " => using language '%s'", allGoodOnes[0]);
+    return allGoodOnes[0];
+}
+
+wxArrayString wxTranslations::GetAcceptableTranslations(const wxString& domain,
+                                                        wxLanguage msgIdLanguage)
+{
+    const wxString lang = wxLocale::GetLanguageCanonicalName(msgIdLanguage);
+    return GetAcceptableTranslations(domain, lang);
+}
+
+wxArrayString wxTranslations::GetAcceptableTranslations(const wxString& domain,
+                                                        const wxString& msgIdLanguage)
+{
     wxArrayString available(GetAvailableTranslations(domain));
     // it's OK to have duplicates, so just add msgid language
     available.push_back(msgIdLanguage);
     available.push_back(msgIdLanguage.BeforeFirst('_'));
 
-    wxLogTrace(TRACE_I18N, "choosing best language for domain '%s'", domain);
+    wxLogTrace(TRACE_I18N, "choosing best languages for domain '%s'", domain);
     LogTraceArray(" - available translations", available);
-    const wxString lang = GetPreferredUILanguage(available);
+    wxArrayString allPreferred;
-    wxLogTrace(TRACE_I18N, " => using language '%s'", lang);
+    GetPreferredUILanguage(available, allPreferred);
-    return lang;
+
+    // explicitly set language should always be preferred the most
+    if ( !m_lang.empty() )
+        allPreferred.insert(allPreferred.begin(), m_lang);
+
+    return allPreferred;
 }