crossthread.h

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/*
    Copyright (C) 2000-2007 Paul 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 __pbd__crossthread_h__
#define __pbd__crossthread_h__

#ifdef check
#undef check
#endif

#include <glibmm/main.h>

#include "pbd/libpbd_visibility.h"

#ifdef PLATFORM_WINDOWS
#include <windows.h>
#endif // PLATFORM_WINDOWS


class LIBPBD_API CrossThreadChannel { 
public:
        CrossThreadChannel(bool non_blocking);
        ~CrossThreadChannel();
        
        void wakeup();
        
        /* if the listening thread cares about the precise message
         * it is being sent, then ::deliver() can be used to send
         * a single byte message rather than a simple wakeup. These
         * two mechanisms should not be used on the same CrossThreadChannel
         * because there is no way to know which byte value will be used
         * for ::wakeup()
         */
        int deliver (char msg);

        int receive (char& msg, bool wait = false);

        void drain ();

        void set_receive_handler (sigc::slot<bool,Glib::IOCondition> s);
        void attach (Glib::RefPtr<Glib::MainContext>);

private:
        friend gboolean cross_thread_channel_call_receive_slot (GIOChannel*, GIOCondition condition, void *data);

        GIOChannel* receive_channel;
        GSource*    receive_source;
        sigc::slot<bool,Glib::IOCondition> receive_slot;

        bool poll_for_request();

#ifndef PLATFORM_WINDOWS
        int fds[2]; // current implementation uses a pipe/fifo
#else

        SOCKET send_socket;
        SOCKET receive_socket;
        struct sockaddr_in recv_address;
#endif

};

#endif /* __pbd__crossthread_h__ */