/clients/roscpp/include/ros/poll_set.h

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#ifndef ROSCPP_POLL_SET_H
#define ROSCPP_POLL_SET_H

#include <vector>
#include "io.h"
#include "common.h"
#include <boost/shared_ptr.hpp>
#include <boost/function.hpp>
#include <boost/thread/mutex.hpp>

namespace ros
{

class Transport;
typedef boost::shared_ptr<Transport> TransportPtr;

/**
 * \brief Manages a set of sockets being polled through the poll() function call.
 *
 * PollSet provides thread-safe ways of adding and deleting sockets, as well as adding
 * and deleting events.
 */
class ROSCPP_DECL PollSet
{
public:
  PollSet();
  ~PollSet();

  typedef boost::function<void(int)> SocketUpdateFunc;
  /**
   * \brief Add a socket.
   *
   * addSocket() may be called from any thread.
   * \param sock The socket to add
   * \param update_func The function to call when a socket has events
   * \param transport The (optional) transport associated with this socket. Mainly
   * used to prevent the transport from being deleted while we're calling the update function
   */
  bool addSocket(int sock, const SocketUpdateFunc& update_func, const TransportPtr& transport = TransportPtr());
  /**
   * \brief Delete a socket
   *
   * delSocket() may be called from any thread.
   * \param sock The socket to delete
   */
  bool delSocket(int sock);

  /**
   * \brief Add events to be polled on a socket
   *
   * addEvents() may be called from any thread.
   * \param sock The socket to add events to
   * \param events The events to add
   */
  bool addEvents(int sock, int events);
  /**
   * \brief Delete events to be polled on a socket
   *
   * delEvents() may be called from any thread.
   * \param sock The socket to delete events from
   * \param events The events to delete
   */
  bool delEvents(int sock, int events);

  /**
   * \brief Process all socket events
   *
   * This function will actually call poll() on the available sockets, and allow
   * them to do their processing.
   *
   * update() may only be called from one thread at a time
   *
   * \param poll_timeout The time, in milliseconds, for the poll() call to timeout after
   * if there are no events.  Note that this does not provide an upper bound for the entire
   * function, just the call to poll()
   */
  void update(int poll_timeout);

  /**
   * \brief Signal our poll() call to finish if it's blocked waiting (see the poll_timeout
   * option for update()).
   */
  void signal();

private:
  /**
   * \brief Creates the native pollset for our sockets, if any have changed
   */
  void createNativePollset();

  /**
   * \brief Called when events have been triggered on our signal pipe
   */
  void onLocalPipeEvents(int events);

  struct SocketInfo
  {
    TransportPtr transport_;
    SocketUpdateFunc func_;
    int fd_;
    int events_;
  };
  typedef std::map<int, SocketInfo> M_SocketInfo;
  M_SocketInfo socket_info_;
  boost::mutex socket_info_mutex_;
  bool sockets_changed_;

  boost::mutex just_deleted_mutex_;
  typedef std::vector<int> V_int;
  V_int just_deleted_;

  std::vector<socket_pollfd> ufds_;

  boost::mutex signal_mutex_;
  signal_fd_t signal_pipe_[2];
};

}

#endif // ROSCPP_POLL_SET_H