Basic keyboard state module

src/factory.cpp

@@ -70,6 +70,11 @@ waybar::AModule* waybar::Factory::makeModule(const std::string& name) const {
       return new waybar::modules::Backlight(id, config_[name]);
     }
 #endif
+#ifdef HAVE_LIBEVDEV
+    if (ref == "keyboard_state") {
+      return new waybar::modules::KeyboardState(id, config_[name]);
+    }
+#endif
 #ifdef HAVE_LIBPULSE
     if (ref == "pulseaudio") {
       return new waybar::modules::Pulseaudio(id, config_[name]);

src/modules/keyboard_state.cpp

@@ -0,0 +1,73 @@
+#include "modules/keyboard_state.hpp"
+#include <filesystem>
+
+extern "C" {
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+}
+
+waybar::modules::KeyboardState::KeyboardState(const std::string& id, const Json::Value& config)
+    : ALabel(config, "keyboard_state", id, "{temperatureC}", 1) {
+  if (config_["device-path"].isString()) {
+    dev_path_ = config_["device-path"].asString();
+  } else {
+    dev_path_ = "";
+  }
+
+  fd_ = open(dev_path_.c_str(), O_NONBLOCK | O_CLOEXEC | O_RDONLY);
+  if (fd_ < 0) {
+    throw std::runtime_error("Can't open " + dev_path_);
+  }
+  int err = libevdev_new_from_fd(fd_, &dev_);
+  if (err < 0) {
+    throw std::runtime_error("Can't create libevdev device");
+  }
+  if (!libevdev_has_event_type(dev_, EV_LED)) {
+    throw std::runtime_error("Device doesn't support LED events");
+  }
+  if (!libevdev_has_event_code(dev_, EV_LED, LED_NUML) || !libevdev_has_event_code(dev_, EV_LED, LED_CAPSL)) {
+    throw std::runtime_error("Device doesn't support num lock or caps lock events");
+  }
+
+  thread_ = [this] {
+    dp.emit();
+    thread_.sleep_for(interval_);
+  };
+}
+
+waybar::modules::KeyboardState::~KeyboardState() {
+  libevdev_free(dev_);
+  int err = close(fd_);
+  if (err < 0) {
+    // Not much we can do, so ignore it.
+  }
+}
+
+auto waybar::modules::KeyboardState::update() -> void {
+  int err = LIBEVDEV_READ_STATUS_SUCCESS;
+  while (err == LIBEVDEV_READ_STATUS_SUCCESS) {
+    input_event ev;
+    err = libevdev_next_event(dev_, LIBEVDEV_READ_FLAG_NORMAL, &ev);
+    while (err == LIBEVDEV_READ_STATUS_SYNC) {
+      err = libevdev_next_event(dev_, LIBEVDEV_READ_FLAG_SYNC, &ev);
+    }
+  }
+  if (err != -EAGAIN) {
+    throw std::runtime_error("Failed to sync evdev device");
+  }
+
+  int numl = libevdev_get_event_value(dev_, EV_LED, LED_NUML);
+  //int capsl = libevdev_get_event_value(dev_, EV_LED, LED_CAPSL);
+
+  std::string text;
+  if (numl) {
+    text = fmt::format(format_, "num lock enabled");
+    label_.set_markup(text);
+  } else {
+    text = fmt::format(format_, "num lock disabled");
+    label_.set_markup(text);
+  }
+
+  ALabel::update();
+}