zeroconf.hpp

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/*****************************************************************************
 ** Includes
 *****************************************************************************/

#include <set>
#include <string>

#include <avahi-client/publish.h>
#include <avahi-client/client.h>
#include <avahi-client/lookup.h>
#include <avahi-common/malloc.h>
#include <avahi-common/error.h>
#include <avahi-common/thread-watch.h>

#include <boost/thread/mutex.hpp>
#include <boost/bimap/bimap.hpp>
#include <boost/function.hpp>
#include <boost/shared_ptr.hpp>

#include <zeroconf_msgs/PublishedService.h>
#include <zeroconf_msgs/DiscoveredService.h>

/*****************************************************************************
 ** Namespaces
 *****************************************************************************/

namespace zeroconf_avahi
{

/*****************************************************************************
 ** Utilities
 *****************************************************************************/
struct PublishedServiceCompare
{
  bool operator()(const zeroconf_msgs::PublishedService &a, const zeroconf_msgs::PublishedService &b) const
  {
    if (a.name != b.name)
    {
      return a.name < b.name;
    }
    else if (a.type != b.type)
    {
      return a.type < b.type;
    }
    else
    {
      return a.port < b.port;
    }
  }
};

class DiscoveredAvahiService
{
public:
  DiscoveredAvahiService() :
      resolver(NULL)
  {
  }
  DiscoveredAvahiService(zeroconf_msgs::DiscoveredService &discovered_service, AvahiServiceResolver *new_resolver,
                         int protocol, int hardware_interface) :
      service(discovered_service), protocol(protocol), hardware_interface(hardware_interface), resolver(new_resolver)
  {

  }
  ~DiscoveredAvahiService()
  {
    if (resolver)
    {
      avahi_service_resolver_free(resolver);
    }
  }
  zeroconf_msgs::DiscoveredService service;
  int protocol;
  int hardware_interface;
  AvahiServiceResolver *resolver;
};

struct DiscoveredAvahiServiceCompare
{
  bool operator()(const boost::shared_ptr<DiscoveredAvahiService> avahi_service_a,
                  const boost::shared_ptr<DiscoveredAvahiService> avahi_service_b) const
  {
    const zeroconf_msgs::DiscoveredService &a = avahi_service_a->service;
    const zeroconf_msgs::DiscoveredService &b = avahi_service_b->service;
    if (a.name != b.name)
    {
      return a.name < b.name;
    }
    else if (a.type != b.type)
    {
      return a.type < b.type;
    }
    else if (a.domain != b.domain)
    {
      return a.domain < b.domain;
    }
    else if (avahi_service_a->hardware_interface != avahi_service_b->hardware_interface)
    {
      return avahi_service_a->hardware_interface < avahi_service_b->hardware_interface;
    }
    else
    {
      return avahi_service_a->protocol < avahi_service_b->protocol;
    }
  }
};

/*****************************************************************************
 ** Interfaces
 *****************************************************************************/
class Zeroconf
{
private:
  typedef zeroconf_msgs::PublishedService PublishedService;
  typedef boost::bimaps::bimap<AvahiEntryGroup*, boost::bimaps::set_of<PublishedService, PublishedServiceCompare> > service_bimap;
  typedef boost::bimaps::bimap<AvahiServiceBrowser*, boost::bimaps::set_of<std::string> > discovery_bimap;
  typedef std::set<boost::shared_ptr<DiscoveredAvahiService>, DiscoveredAvahiServiceCompare> discovered_service_set;
  typedef std::pair<AvahiEntryGroup*, PublishedService> service_map_pair;
  typedef boost::function<void(zeroconf_msgs::DiscoveredService)> connection_signal_cb;

public:
  Zeroconf();
  ~Zeroconf();
  bool add_service(PublishedService &service);
  bool remove_service(const PublishedService &service);
  // Todo : would be useful to be able to remove services in various other ways
  // bool remove_services_by_name(const std::string& service_name);
  // bool remove_services_by_type(const std::string& service_type);
  // bool remove_services() <-- remove *all* services
  bool add_listener(std::string &service_type);
  bool remove_listener(const std::string &service_type);
  void list_discovered_services(const std::string &service_type, std::vector<zeroconf_msgs::DiscoveredService> &list);
  void list_published_services(const std::string &service_type, std::vector<zeroconf_msgs::PublishedService> &list);

  void connect_signal_callbacks(connection_signal_cb new_connections, connection_signal_cb lost_connections)
  {
    new_connection_signal = new_connections;
    lost_connection_signal = lost_connections;
  }

  void spin();

private:
  bool invalid_object;
  AvahiThreadedPoll *threaded_poll;
  AvahiClient *client;
  service_bimap committed_services;
  service_bimap established_services;
  discovery_bimap discovery_service_types;
  discovered_service_set discovered_services;
  boost::mutex service_mutex;
  const int interface;
  const int permitted_protocols;
  connection_signal_cb new_connection_signal, lost_connection_signal;

  /*********************
   ** Utilitiies
   **********************/
  int ros_to_avahi_protocol(const int &protocol);
  std::string ros_to_txt_protocol(const int &protocol);
  int avahi_to_ros_protocol(const int &protocol);
  std::string avahi_to_txt_protocol(const int &protocol);
  discovered_service_set::iterator find_discovered_service(zeroconf_msgs::DiscoveredService &service);

  /*********************
   ** Mechanics
   **********************/
  bool add_service_non_threaded(PublishedService &service);
  void fail()
  {
    avahi_threaded_poll_quit(threaded_poll);
    invalid_object = true;
  }

  /*********************
   ** Callbacks
   **********************/
  static void entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, void *userdata);
  static void client_callback(AvahiClient *c, AvahiClientState state, void * userdata);
  static void discovery_callback(AvahiServiceBrowser *b, AvahiIfIndex interface, AvahiProtocol protocol,
                                 AvahiBrowserEvent event, const char *name, const char *type, const char *domain,
                                 AvahiLookupResultFlags flags, void* userdata);
  static void resolve_callback(AvahiServiceResolver *r, AvahiIfIndex interface, AvahiProtocol protocol,
                               AvahiResolverEvent event, const char *name, const char *type, const char *domain,
                               const char *host_name, const AvahiAddress *address, uint16_t port, AvahiStringList *txt,
                               AvahiLookupResultFlags flags, void* userdata);
  static void modify_callback(AVAHI_GCC_UNUSED AvahiTimeout *e, void *userdata);
};

} // namespace zeroconf_avahi