The Pier Shareware 6/The_Pier_Shareware_Number_6_(The_Pier_Exchange)_(1995).iso/036/less232.zip/SIGNAL.C

C/C++ Source or Header | 1994-09-22 | 5KB | 247 lines

/*
 * Copyright (c) 1984,1985,1989,1994  Mark Nudelman
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice in the documentation and/or other materials provided with
 *    the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


/*
 * Routines dealing with signals.
 *
 * A signal usually merely causes a bit to be set in the "signals" word.
 * At some convenient time, the mainline code checks to see if any
 * signals need processing by calling psignal().
 * If we happen to be reading from a file [in iread()] at the time
 * the signal is received, we call intread to interrupt the iread.
 */

#include "less.h"
#include <signal.h>

/*
 * "sigs" contains bits indicating signals which need to be processed.
 */
public int sigs;

extern int sc_width, sc_height;
extern int screen_trashed;
extern int lnloop;
extern int linenums;
extern int wscroll;
extern int reading;

/*
 * Interrupt signal handler.
 */
    /* ARGSUSED*/
    static RETSIGTYPE
u_interrupt(type)
    int type;
{
    SIGNAL(SIGINT, u_interrupt);
    sigs |= S_INTERRUPT;
    if (reading)
        intread();
}

    public void
fake_interrupt()
{
    sigs |= S_INTERRUPT;
}

#ifdef SIGTSTP
/*
 * "Stop" (^Z) signal handler.
 */
    /* ARGSUSED*/
    static RETSIGTYPE
stop(type)
    int type;
{
    SIGNAL(SIGTSTP, stop);
    sigs |= S_STOP;
    if (reading)
        intread();
}
#endif

#ifdef SIGWINCH
/*
 * "Window" change handler
 */
    /* ARGSUSED*/
    public RETSIGTYPE
winch(type)
    int type;
{
    SIGNAL(SIGWINCH, winch);
    sigs |= S_WINCH;
    if (reading)
        intread();
}
#else
#ifdef SIGWIND
/*
 * "Window" change handler
 */
    /* ARGSUSED*/
    public RETSIGTYPE
winch(type)
    int type;
{
    SIGNAL(SIGWIND, winch);
    sigs |= S_WINCH;
    if (reading)
        intread();
}
#endif
#endif

/*
 * Set up the signal handlers.
 */
    public void
init_signals(on)
    int on;
{
    if (on)
    {
        /*
         * Set signal handlers.
         */
        (void) SIGNAL(SIGINT, u_interrupt);
#ifdef SIGTSTP
        (void) SIGNAL(SIGTSTP, stop);
#endif
#ifdef SIGWINCH
        (void) SIGNAL(SIGWINCH, winch);
#else
#ifdef SIGWIND
        (void) SIGNAL(SIGWIND, winch);
#endif
#endif
    } else
    {
        /*
         * Restore signals to defaults.
         */
        (void) SIGNAL(SIGINT, SIG_DFL);
#ifdef SIGTSTP
        (void) SIGNAL(SIGTSTP, SIG_DFL);
#endif
#ifdef SIGWINCH
        (void) SIGNAL(SIGWINCH, SIG_IGN);
#endif
#ifdef SIGWIND
        (void) SIGNAL(SIGWIND, SIG_IGN);
#endif
    }
}

/*
 * Process any signals we have received.
 * A received signal cause a bit to be set in "sigs".
 */
    public void
psignals()
{
    register int tsignals;

    if ((tsignals = sigs) == 0)
        return;
    sigs = 0;

#ifdef SIGTSTP
    if (tsignals & S_STOP)
    {
        /*
         * Clean up the terminal.
         */
#ifdef SIGTTOU
        SIGNAL(SIGTTOU, SIG_IGN);
#endif
        clear_bot();
        deinit();
        flush();
        raw_mode(0);
#ifdef SIGTTOU
        SIGNAL(SIGTTOU, SIG_DFL);
#endif
        SIGNAL(SIGTSTP, SIG_DFL);
        kill(getpid(), SIGTSTP);
        /*
         * ... Bye bye. ...
         * Hopefully we'll be back later and resume here...
         * Reset the terminal and arrange to repaint the
         * screen when we get back to the main command loop.
         */
        SIGNAL(SIGTSTP, stop);
        raw_mode(1);
        init();
        screen_trashed = 1;
        tsignals |= S_WINCH;
    }
#endif
#ifdef S_WINCH
    if (tsignals & S_WINCH)
    {
        int old_width, old_height;
        /*
         * Re-execute scrsize() to read the new window size.
         */
        old_width = sc_width;
        old_height = sc_height;
        scrsize();
        pos_init();
        if (sc_width != old_width || sc_height != old_height)
        {
            wscroll = (sc_height + 1) / 2;
            screen_trashed = 1;
        }
    }
#endif
    if (tsignals & S_INTERRUPT)
    {
        bell();
        /*
         * {{ You may wish to replace the bell() with
         *    error("Interrupt", NULL_PARG); }}
         */

        /*
         * If we were interrupted while in the "calculating
         * line numbers" loop, turn off line numbers.
         */
        if (lnloop)
        {
            lnloop = 0;
            if (linenums == 2)
                screen_trashed = 1;
            linenums = 0;
            error("Line numbers turned off", NULL_PARG);
        }

    }
}