selectable.h

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/*
    Copyright (C) 1998-99 Paul Barton-Davis

    This program 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 2 of the License, or
    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef __selectable_h__
#define __selectable_h__

#include <list>
#include <string>
#include <stdio.h>

#include <sigc++/sigc++.h>

#include <sys/types.h>

#include "pbd/libpbd_visibility.h"

namespace Select {
    enum LIBPBD_API Condition {
                Readable = 0x1,
                Writable = 0x2,
                Exception = 0x4
    };

class LIBPBD_API Selectable : public sigc::trackable

{
  public:
        Selectable (int fd);
        Selectable (const std::string &, int flags, int mode = 0);
        Selectable (FILE *);
        ~Selectable ();

        sigc::signal<void,Selectable *,Select::Condition> readable;
        sigc::signal<void,Selectable *,Select::Condition> writable;
        sigc::signal<void,Selectable *,Select::Condition> exceptioned;

        int  fd() { return _fd; }
        bool ok() { return _ok; }

  protected:
        void selected (unsigned int condition);
        int condition;
        int _fd;

        friend class Selector;

  private:
        enum {
                fromFD,
                fromPath,
                fromFILE
        };
                
        bool _ok;
        int _type;
        std::string path;
};

class LIBPBD_API Selector {
  private:
        int post_select (fd_set *, fd_set *, fd_set *);
        int _max_fd;

        typedef std::list<Selectable *> Selectables;
        Selectables selectables;
        pthread_mutex_t list_lock;

        static bool use_list_lock;

  public:
        Selector ();

        void multithreaded (bool yn) {
                use_list_lock = yn;
        }
        
        void add (int condition, Selectable *s);
        void remove (Selectable *);
        int select (unsigned long usecs);
};



} /* namespace */


#endif // __selectable_h__