Add config for time widget locale (#44)

This makes the `DateTimeStyle` string respect the current locale or
whatever valid locale is set via configuration option `DateTimeLocale`.

---------

Co-authored-by: Sebastian Zerbe <zerbe@phil.hhu.de>

data/config

@@ -60,6 +60,9 @@ TimeSpace: 300
 # Set datetime style
 # DateTimeStyle: %a %D - %H:%M:%S %Z
 
+# Set datetime locale (defaults to system locale if not set or set to empty string)
+# DateTimeLocale: de_DE.utf8
+
 # Adds a audio input(aka. microphone) widget
 AudioInput: false
 

src/Config.cpp

@@ -177,6 +177,7 @@ void Config::Load()
         AddConfigVar("BatteryFolder", config.batteryFolder, lineView, foundProperty);
         AddConfigVar("DefaultWorkspaceSymbol", config.defaultWorkspaceSymbol, lineView, foundProperty);
         AddConfigVar("DateTimeStyle", config.dateTimeStyle, lineView, foundProperty);
+        AddConfigVar("DateTimeLocale", config.dateTimeLocale, lineView, foundProperty);
         AddConfigVar("CheckPackagesCommand", config.checkPackagesCommand, lineView, foundProperty);
         for (int i = 1; i < 10; i++)
         {

src/Config.h

@@ -16,6 +16,7 @@ public:
     std::vector<std::string> workspaceSymbols = std::vector<std::string>(9, "");
     std::string defaultWorkspaceSymbol = "";
     std::string dateTimeStyle = "%a %D - %H:%M:%S %Z"; // A sane default
+    std::string dateTimeLocale = ""; // use system locale
 
     // Script that returns how many packages are out-of-date. The script should only print a number!
     // See data/update.sh for a human-readable version

src/System.cpp

@@ -605,6 +605,7 @@ namespace System
         time_t stdTime = time(NULL);
         tm* localTime = localtime(&stdTime);
         std::stringstream str;
+        str.imbue(std::locale(Config::Get().dateTimeLocale.c_str()));
         str << std::put_time(localTime, Config::Get().dateTimeStyle.c_str());
         return str.str();
     }