// SignalHandler.cc for FbTk - Fluxbox ToolKit
// Copyright (c) 2002 - 2006 Henrik Kinnunen (fluxgen at fluxbox dot 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.

#include "SignalHandler.hh"

namespace FbTk {

SignalEventHandler *SignalHandler::s_signal_handler[NSIG];

SignalHandler::SignalHandler() {
    // clear signal list
    for (int i=0; i < NSIG; ++i)
        s_signal_handler[i] = 0;
}

SignalHandler &SignalHandler::instance() {
    static SignalHandler singleton;
    return singleton;
}

bool SignalHandler::registerHandler(int signum, SignalEventHandler *eh,
                                    SignalEventHandler **oldhandler_ret) {
    // must be less than NSIG
    if (signum >= NSIG)
        return false;

    // get old signal handler for this signum
    if (oldhandler_ret != 0)
        *oldhandler_ret = s_signal_handler[signum];

#ifdef HAVE_SIGACTION
    struct sigaction sa;
    // set callback
    sa.sa_handler = SignalHandler::handleSignal;
    sigemptyset (&sa.sa_mask);
    sa.sa_flags = 0;

    if (sigaction(signum, &sa, 0) == -1)
        return false;
#else
    // Fallback code for Windows and other platforms lacking sigaction.
    if (signal(signum, &SignalHandler::handleSignal) == SIG_ERR) {
        return false;
    }
#endif
    s_signal_handler[signum] = eh;

    return true;
}

void SignalHandler::handleSignal(int signum) {
    if (signum >= NSIG)
        return;
    // make sure we got a handler for this signal
    if (s_signal_handler[signum] != 0) {
        s_signal_handler[signum]->handleSignal(signum);
    }
}

}

