/* -*- c++ -*- */
/*
 * Copyright 2005,2013 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef INCLUDED_GR_SELECT_HANDLER_H
#define INCLUDED_GR_SELECT_HANDLER_H

#include <gnuradio/api.h>
#include <boost/shared_ptr.hpp>

namespace gr {

  class select_handler;
  typedef boost::shared_ptr<select_handler> select_handler_sptr;

  /*!
   * \brief Abstract handler for select based notification.
   * \ingroup base
   *
   * \sa gr::dispatcher
   */
  class GR_RUNTIME_API select_handler
  {
    int d_fd;

  protected:
    select_handler(int file_descriptor);

  public:
    virtual ~select_handler();

    int fd() const { return d_fd; }
    int file_descriptor() const { return d_fd; }

    /*!
     * \brief Called when file_descriptor is readable.
     *
     * Called when the dispatcher detects that file_descriptor can be
     * read without blocking.
     */
    virtual void handle_read() = 0;

    /*!
     * \brief Called when file_descriptor is writable.
     *
     * Called when dispatcher detects that file descriptor can be
     * written without blocking.
     */
    virtual void handle_write() = 0;

    /*!
     * Called each time around the dispatcher loop to determine
     * whether this handler's file descriptor should be added to the
     * list on which read events can occur. The default method
     * returns true, indicating that by default, all handlers are
     * interested in read events.
     */
    virtual bool readable() { return true; }

    /*!
     * Called each time around the dispatcher loop to determine
     * whether this handler's file descriptor should be added to the
     * list on which write events can occur. The default method
     * returns true, indicating that by default, all handlers are
     * interested in write events.
     */
    virtual bool writable() { return true; }
  };

} /* namespace gr */

#endif /* INCLUDED_GR_SELECT_HANDLER_H */