// SignalHandler.hh for FbTk
// Copyright (c) 2002 Henrik Kinnunen (fluxgen@linuxmail.org)
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.	IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

// $Id: SignalHandler.hh,v 1.3 2002/12/01 13:42:14 rathnor Exp $

#ifndef FBTK_SIGNALHANDLER_HH
#define FBTK_SIGNALHANDLER_HH

#include <signal.h>

namespace FbTk {


class SignalEventHandler {
public:
    virtual void handleSignal(int signum) = 0;
};

/**
   Handles system signals, singleton.
   Usage: inherit the class EventHandler and then register 
   it to SignalHandler by calling registerHandler with
   a signal number
*/
class SignalHandler {
public:
    /// get singleton object
    static SignalHandler *instance();
    /** 
        Register an event handler
        @return true on success else false
        @param signum signal number
        @param eh event handler
        @param oldhandler_ret return handler to old sighandler
    */
    bool registerHandler(int signum, SignalEventHandler *eh, SignalEventHandler **oldhandler_ret = 0);
    /**
       removes the signum handler
       @param signum signal number
    */
    void removeHandler(int signum);
private:
    SignalHandler();

    static void handleSignal(int signum);

    static SignalEventHandler *s_signal_handler[NSIG]; ///< NSIG defined in signal.h
}; 

}; // end namespace FbTk

#endif // FBTK_SIGNALHANDLER_HH