Localizations may not work on Linux

[Infocatcher]

See https://forum.mozilla-russia.org/viewtopic.php?id=54385

So we should use

Components.classes["@mozilla.org/chrome/chrome-registry;1"]
    .getService(Components.interfaces.nsIXULChromeRegistry)
    .getSelectedLocale("global");

or

Components.classes["@mozilla.org/preferences-service;1"]
    .getService(Components.interfaces.nsIPrefBranch)
    .getComplexValue("general.useragent.locale", Components.interfaces.nsIPrefLocalizedString)
    .data;

But with getSelectedLocale() we need to have installed language pack to test localization (or change code each time).

[Infocatcher]

getComplexValue() seems to work fine on Linux, but doesn't work for default value on Windows:

Exception: Component returned failure code: 0x8000ffff (NS_ERROR_UNEXPECTED) [nsIPrefBranch.getComplexValue]

getCharPref(): always works on Windows, but returns chrome://global/locale/intl.properties on Linux for default value.

getSelectedLocale(): seems to always works, but only if installed corresponding language pack for browser.

Also with intl.locale.matchOS = true general.useragent.locale isn't used at all.

[Infocatcher]

D'oh...

(function() {
    //var prefs = Services.prefs; 
    var prefs = Components.classes["@mozilla.org/preferences-service;1"]
        .getService(Components.interfaces.nsIPrefBranch);
    if(!prefs.getBoolPref("intl.locale.matchOS")) {
        var locale = prefs.getCharPref("general.useragent.locale");
        if(locale.substr(0, 9) != "chrome://")
            return locale;
    }
    return Components.classes["@mozilla.org/chrome/chrome-registry;1"]
        .getService(Components.interfaces.nsIXULChromeRegistry)
        .getSelectedLocale("global");
})().match(/^[a-z]*/)[0];

[Infocatcher]

Also for OS locale:

Components.classes["@mozilla.org/intl/nslocaleservice;1"]
    .getService(Components.interfaces.nsILocaleService)
    .getSystemLocale()
    .getCategory("NSILOCALE_COLLATE");

https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsILocaleService https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsILocale

[Infocatcher]

Alternative way:

Services.urlFormatter.formatURL("%LOCALE%")

https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIURLFormatter http://mxr.mozilla.org/mozilla-central/source/toolkit/components/urlformatter/nsURLFormatter.js#90

  _defaults: {
    LOCALE:           function() Cc["@mozilla.org/chrome/chrome-registry;1"].
                                 getService(Ci.nsIXULChromeRegistry).
                                 getSelectedLocale('global'),