add signalhandler for module update

src/ALabel.cpp

@@ -6,8 +6,9 @@
 waybar::ALabel::ALabel(const Json::Value& config, const std::string format, uint16_t interval)
   : config_(config),
     format_(config_["format"].isString() ? config_["format"].asString() : format),
-    interval_(std::chrono::seconds(config_["interval"].isUInt()
-      ? config_["interval"].asUInt() : interval)), default_format_(format_)
+    interval_(config_["interval"] == "once" ? std::chrono::seconds(100000000) :
+      std::chrono::seconds(config_["interval"].isUInt() ?
+      config_["interval"].asUInt() : interval)), default_format_(format_)
 {
   event_box_.add(label_);
 	if (config_["max-length"].isUInt()) {

src/bar.cpp

@@ -185,6 +185,22 @@ void waybar::Bar::handleDescription(void* /*data*/,
   // Nothing here
 }
 
+void waybar::Bar::handleSignal(int signal)
+{
+  for (auto& module : modules_left_) {
+    auto* custom = dynamic_cast<waybar::modules::Custom*>(module.get());
+    if(custom) custom->refresh(signal);
+  }
+  for (auto& module : modules_center_) {
+    auto* custom = dynamic_cast<waybar::modules::Custom*>(module.get());
+    if(custom) custom->refresh(signal);
+  }
+  for (auto& module : modules_right_) {
+    auto* custom = dynamic_cast<waybar::modules::Custom*>(module.get());
+    if(custom) custom->refresh(signal);
+  }
+}
+
 void waybar::Bar::layerSurfaceHandleConfigure(void* data,
   struct zwlr_layer_surface_v1* surface, uint32_t serial, uint32_t width,
   uint32_t height)

src/main.cpp

@@ -19,6 +19,14 @@ int main(int argc, char* argv[])
       }
     });
 
+    for (int sig = SIGRTMIN + 1; sig <= SIGRTMAX; ++sig) {
+      std::signal(sig, [] (int sig/*signal*/) {
+        for (auto& bar : waybar::client->bars) {
+          bar->handleSignal(sig);
+        }
+      });
+    }
+
     return c.main(argc, argv);
   } catch (const std::exception& e) {
     std::cerr << e.what() << std::endl;

src/modules/custom.cpp

@@ -78,6 +78,13 @@ void waybar::modules::Custom::continuousWorker()
   };
 }
 
+void waybar::modules::Custom::refresh(int sig /*signal*/)
+{
+  if(sig == SIGRTMIN + config_["signal"].asInt()) {
+    thread_.wake_up();
+  }
+}
+
 auto waybar::modules::Custom::update() -> void
 {
   // Hide label if output is empty