add rudimentary bluetooth module functionality

include/modules/bluetooth.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <fmt/format.h>
+#include "ALabel.hpp"
+
+namespace waybar::modules {
+
+class Bluetooth : public ALabel {
+ public:
+  Bluetooth(const std::string&, const Json::Value&);
+  ~Bluetooth() = default;
+  auto update() -> void;
+
+ private:
+  ;
+};
+
+}  // namespace waybar::modules

include/util/rfkill.hpp

@@ -0,0 +1,55 @@
+#pragma once
+
+#include <linux/rfkill.h>
+#include <unistd.h>
+//#include <stdlib.h>
+#include <cstring>
+#include <linux/rfkill.h>
+#include <fcntl.h>
+
+namespace waybar::util {
+
+bool isDisabled(enum rfkill_type rfkill_type) {
+  struct rfkill_event event;
+  ssize_t len;
+  int fd;
+  int ret;
+  ret = false;
+
+  fd = open("/dev/rfkill", O_RDONLY);
+  if (fd < 0) {
+    perror("Can't open RFKILL control device");
+    return false;
+  }
+
+  if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
+    perror("Can't set RFKILL control device to non-blocking");
+    close(fd);
+    return false;
+  }
+
+  while(true) {
+    len = read(fd, &event, sizeof(event));
+    if (len < 0) {
+      if (errno == EAGAIN)
+        return 1;
+      perror("Reading of RFKILL events failed");
+      return false;
+    }
+
+    if (len != RFKILL_EVENT_SIZE_V1) {
+      fprintf(stderr, "Wrong size of RFKILL event\n");
+      return false;
+    }
+
+    if(event.type == rfkill_type) {
+      ret = event.soft || event.hard;
+      break;
+    }
+  }
+
+  close(fd);
+  return ret;
+}
+
+}  // namespace waybar::util

src/modules/bluetooth.cpp

@@ -0,0 +1,29 @@
+#include "modules/bluetooth.hpp"
+#include "util/rfkill.hpp"
+#include <linux/rfkill.h>
+
+waybar::modules::Bluetooth::Bluetooth(const std::string& id, const Json::Value& config)
+    : ALabel(config, "bluetooth", id, "{status}", 10) {
+  dp.emit();
+}
+
+auto waybar::modules::Bluetooth::update() -> void {
+  auto text = "enabled";
+  if (waybar::util::isDisabled(RFKILL_TYPE_BLUETOOTH)) {
+    text = "disabled";
+  } else {
+    text = "enabled";
+  }
+
+  label_.set_markup(text);
+
+  if (tooltipEnabled()) {
+    if (config_["tooltip-format"].isString()) {
+      auto tooltip_format = config_["tooltip-format"].asString();
+      auto tooltip_text = fmt::format(tooltip_format, localtime);
+      label_.set_tooltip_text(tooltip_text);
+    } else {
+      label_.set_tooltip_text(text);
+    }
+  }
+}