/***************************************************************************
 *   Copyright (C) 2010 by Joris Guisson                                   *
 *   joris.guisson@gmail.com                                               *
 *                                                                         *
 *   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.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.          *
 ***************************************************************************/

#ifndef BT_SIGNALCATCHER_H
#define BT_SIGNALCATCHER_H

#ifndef Q_WS_WIN

#include <ktorrent_export.h>
#include <signal.h>
#include <setjmp.h>
#include <QObject>
#include <QSocketNotifier>
#include <util/error.h>

namespace bt
{
/**
    Variable used to jump from the SIGBUS handler back to the place which triggered the SIGBUS.
*/
extern KTORRENT_EXPORT sigjmp_buf sigbus_env;

/**
 * Protects against SIGBUS errors when doing mmapped IO
 **/
class KTORRENT_EXPORT BusErrorGuard
{
public:
    BusErrorGuard();
    virtual ~BusErrorGuard();
};

/**
    Exception throw when a SIGBUS is caught.
*/
class KTORRENT_EXPORT BusError : public bt::Error
{
public:
    BusError(bool write_operation);
    ~BusError() override;

    /// Whether or not the SIGBUS was triggered by a write operation
    bool write_operation;
};

/**
 * Class to handle UNIX signals (not Qt ones)
 */
class KTORRENT_EXPORT SignalCatcher : public QObject
{
    Q_OBJECT
public:
    SignalCatcher(QObject* parent = 0);
    ~SignalCatcher() override;

    /**
     * Catch a UNIX signal
     * @param sig SIGINT, SIGTERM or some other signal
     * @return true upon success, false otherwise
     **/
    bool catchSignal(int sig);

private Q_SLOTS:
    void handleInput(int fd);

private:
    static void signalHandler(int sig, siginfo_t *siginfo, void *ptr);

Q_SIGNALS:
    /// Emitted when a
    void triggered();

private:
    QSocketNotifier* notifier;
    static int signal_received_pipe[2];
};
}

/// Before writing to memory mapped data, call this macro to ensure that SIGBUS signals are caught and properly dealt with
#define BUS_ERROR_WPROTECT() BusErrorGuard bus_error_guard; if (sigsetjmp(bt::sigbus_env, 1)) throw bt::BusError(true)

/// Before reading from memory mapped data, call this macro to ensure that SIGBUS signals are caught and properly dealt with
#define BUS_ERROR_RPROTECT() BusErrorGuard bus_error_guard; if (sigsetjmp(bt::sigbus_env, 1)) throw bt::BusError(false)

#endif

#endif // BT_SIGNALCATCHER_H
