OS/2 Shareware BBS: 6 File/06-File.zip/less373.zip/signal.c

C/C++ Source or Header | 2002-01-14 | 5KB | 271 lines

/*
 * Copyright (C) 1984-2000  Mark Nudelman
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Less License, as specified in the README file.
 *
 * For more information about less, or for information on how to
 * contact the author, see the README file.
 */


/*
 * 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;
{
#if OS2
    LSIGNAL(SIGINT, SIG_ACK);
#endif
    LSIGNAL(SIGINT, u_interrupt);
    sigs |= S_INTERRUPT;
#if MSDOS_COMPILER==DJGPPC
    /*
     * If a keyboard has been hit, it must be Ctrl-C
     * (as opposed to Ctrl-Break), so consume it.
     * (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
     */
    if (kbhit())
        getkey();
#endif
    if (reading)
        intread();
}

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

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

#if MSDOS_COMPILER==WIN32C
/*
 * Handle CTRL-C and CTRL-BREAK keys.
 */
#include "windows.h"

    static BOOL WINAPI
wbreak_handler(dwCtrlType)
    DWORD dwCtrlType;
{
    switch (dwCtrlType)
    {
    case CTRL_C_EVENT:
    case CTRL_BREAK_EVENT:
        sigs |= S_INTERRUPT;
        return (TRUE);
    default:
        break;
    }
    return (FALSE);
}
#endif

/*
 * Set up the signal handlers.
 */
    public void
init_signals(on)
    int on;
{
    if (on)
    {
        /*
         * Set signal handlers.
         */
        (void) LSIGNAL(SIGINT, u_interrupt);
#if MSDOS_COMPILER==WIN32C
        SetConsoleCtrlHandler(wbreak_handler, TRUE);
#endif
#ifdef SIGTSTP
        (void) LSIGNAL(SIGTSTP, stop);
#endif
#ifdef SIGWINCH
        (void) LSIGNAL(SIGWINCH, winch);
#else
#ifdef SIGWIND
        (void) LSIGNAL(SIGWIND, winch);
#endif
#ifdef SIGQUIT
        (void) LSIGNAL(SIGQUIT, SIG_IGN);
#endif
#endif
    } else
    {
        /*
         * Restore signals to defaults.
         */
        (void) LSIGNAL(SIGINT, SIG_DFL);
#if MSDOS_COMPILER==WIN32C
        SetConsoleCtrlHandler(wbreak_handler, FALSE);
#endif
#ifdef SIGTSTP
        (void) LSIGNAL(SIGTSTP, SIG_DFL);
#endif
#ifdef SIGWINCH
        (void) LSIGNAL(SIGWINCH, SIG_IGN);
#endif
#ifdef SIGWIND
        (void) LSIGNAL(SIGWIND, SIG_IGN);
#endif
#ifdef SIGQUIT
        (void) LSIGNAL(SIGQUIT, SIG_DFL);
#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
        LSIGNAL(SIGTTOU, SIG_IGN);
#endif
        clear_bot();
        deinit();
        flush();
        raw_mode(0);
#ifdef SIGTTOU
        LSIGNAL(SIGTTOU, SIG_DFL);
#endif
        LSIGNAL(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.
         */
        LSIGNAL(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;
        get_term();
        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);
        }

    }
}