Add timezone support to clock module (closes #223)

man/waybar-clock.5.scd

@@ -20,6 +20,11 @@ The *clock* module displays the current date and time.
 	default: {:%H:%M} ++
 	The format, how the date and time should be displayed.
 
+*timezone*: ++
+	typeof: string ++
+	default: inferred local timezone ++
+	The timezone to display the time in, e.g. America/New_York.
+
 *max-length*: ++
 	typeof: integer ++
 	The maximum length in character the module should display.

meson.build

@@ -66,6 +66,8 @@ gtk_layer_shell = dependency('gtk-layer-shell-0',
         required: get_option('gtk-layer-shell'),
         fallback : ['gtk-layer-shell', 'gtk_layer_shell_dep'])
 systemd = dependency('systemd', required: get_option('systemd'))
+date_dep = dependency('date', default_options : [ 'use_system_tzdb=true' ], fallback: [ 'date', 'date_dep' ])
+tz_dep = dependency('date', default_options : [ 'use_system_tzdb=true' ], fallback: [ 'date', 'tz_dep' ])
 
 prefix = get_option('prefix')
 conf_data = configuration_data()
@@ -166,7 +168,9 @@ executable(
         libpulse,
         libudev,
         libmpdclient,
-        gtk_layer_shell
+        gtk_layer_shell,
+        date_dep,
+        tz_dep
     ],
     include_directories: [include_directories('include')],
     install: true,

resources/config

@@ -64,6 +64,7 @@
         "spacing": 10
     },
     "clock": {
+        // "timezone": "America/New_York",
         "tooltip-format": "{:%Y-%m-%d | %H:%M}",
         "format-alt": "{:%Y-%m-%d}"
     },

src/modules/clock.cpp

@@ -1,5 +1,5 @@
 #include "modules/clock.hpp"
-#include <time.h>
+#include <date/tz.h>
 
 waybar::modules::Clock::Clock(const std::string& id, const Json::Value& config)
     : ALabel(config, "clock", id, "{:%H:%M}", 60) {
@@ -14,8 +14,14 @@ waybar::modules::Clock::Clock(const std::string& id, const Json::Value& config)
 
 auto waybar::modules::Clock::update() -> void {
   tzset(); // Update timezone information
-  auto now = std::chrono::system_clock::now();
+  const date::time_zone* zone;
-  auto localtime = fmt::localtime(std::chrono::system_clock::to_time_t(now));
+  auto now = std::chrono::floor<std::chrono::seconds>(std::chrono::system_clock::now());
+  if (config_["timezone"].isString()) {
+    zone = date::locate_zone(config_["timezone"].asString());
+  } else {
+    zone = date::current_zone();
+  }
+  auto localtime = date::make_zoned(zone, now);
   auto text = fmt::format(format_, localtime);
   label_.set_markup(text);
 
@@ -29,3 +35,23 @@ auto waybar::modules::Clock::update() -> void {
     }
   }
 }
+
+template <typename ZonedTimeInner>
+struct fmt::formatter<date::zoned_time<ZonedTimeInner>> {
+
+  std::string *format_string;
+
+  constexpr auto parse(format_parse_context& ctx) {
+    format_string = new std::string[1];
+    auto it = ctx.begin(), end = ctx.end();
+    while (it != (end - 1)) {
+      *format_string += *it++;
+    }
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(const date::zoned_time<ZonedTimeInner>& d, FormatContext& ctx) {
+    return format_to(ctx.out(), "{}", date::format(*format_string, d));
+  }
+};

subprojects/date.wrap

@@ -0,0 +1,9 @@
+[wrap-file]
+source_url=https://github.com/HowardHinnant/date/archive/v2.4.1.tar.gz
+source_filename=date-2.4.1.tar.gz
+source_hash=98907d243397483bd7ad889bf6c66746db0d7d2a39cc9aacc041834c40b65b98
+directory=date-2.4.1
+
+patch_url = https://wrapdb.mesonbuild.com/v1/projects/hinnant-date/2.4.1/1/get_zip
+patch_filename = hinnant-date-2.4.1-1-wrap.zip
+patch_hash = 2061673a6f8e6d63c3a40df4da58fa2b3de2835fd9b3e74649e8279599f3a8f6