lokinet/llarp/linux/dbus.hpp

#pragma once

extern "C"
{
#include <systemd/sd-bus.h>
}
#include <memory>
#include <stdexcept>
#include <string>

namespace llarp::linux
{
  /// exception for connecting to system bus
  class system_bus_exception : public std::runtime_error
  {
   public:
    explicit system_bus_exception(int err);
  };

  /// exception for a failed calling of a dbus method
  class dbus_call_exception : public std::runtime_error
  {
   public:
    explicit dbus_call_exception(std::string meth, int err);
  };

  class DBUS
  {
    struct sd_bus_deleter
    {
      void
      operator()(sd_bus* ptr) const
      {
        sd_bus_unref(ptr);
      }
    };
    std::unique_ptr<sd_bus, sd_bus_deleter> m_ptr;
    const std::string m_interface;
    const std::string m_instance;
    const std::string m_call;

   public:
    DBUS(std::string _interface, std::string _instance, std::string _call);

    template <typename... T>
    void
    operator()(std::string method, const char* arg_format, T... args)
    {
      sd_bus_error error = SD_BUS_ERROR_NULL;
      sd_bus_message* msg = nullptr;
      auto r = sd_bus_call_method(
          m_ptr.get(),
          m_interface.c_str(),
          m_instance.c_str(),
          m_call.c_str(),
          method.c_str(),
          &error,
          &msg,
          arg_format,
          args...);

      if (r < 0)
        throw dbus_call_exception{std::move(method), r};

      sd_bus_message_unref(msg);
      sd_bus_error_free(&error);
    }
  };
}  // namespace llarp::linux