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[nvi.git] / cl / cl_screen.c

/*-
 * Copyright (c) 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1993, 1994, 1995, 1996
 *      Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "$Id: cl_screen.c,v 10.52 2000/07/04 21:48:53 skimo Exp $ (Berkeley) $Date: 2000/07/04 21:48:53 $";
#endif /* not lint */

#include <sys/types.h>
#include <sys/queue.h>

#include <bitstring.h>
#include <curses.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

#include "../common/common.h"
#include "cl.h"

static int      cl_ex_end __P((GS *));
static int      cl_ex_init __P((SCR *));
static void     cl_freecap __P((CL_PRIVATE *));
static int      cl_vi_end __P((GS *));
static int      cl_vi_init __P((SCR *));
static int      cl_putenv __P((char *, char *, u_long));

/*
 * cl_screen --
 *      Switch screen types.
 *
 * PUBLIC: int cl_screen __P((SCR *, u_int32_t));
 */
int
cl_screen(sp, flags)
        SCR *sp;
        u_int32_t flags;
{
        CL_PRIVATE *clp;
        WINDOW *win;
        GS *gp;

        gp = sp->gp;
        clp = CLP(sp);
        win = CLSP(sp) ? CLSP(sp) : stdscr;

        /* See if the current information is incorrect. */
        if (F_ISSET(gp, G_SRESTART)) {
                if (CLSP(sp)) {
                    delwin(CLSP(sp));
                    CLSP(sp) = NULL;
                }
                if (cl_quit(gp))
                        return (1);
                F_CLR(gp, G_SRESTART);
        }
        
        /* See if we're already in the right mode. */
        if (LF_ISSET(SC_EX) && F_ISSET(sp, SC_SCR_EX) ||
            LF_ISSET(SC_VI) && F_ISSET(sp, SC_SCR_VI))
                return (0);

        /*
         * Fake leaving ex mode.
         *
         * We don't actually exit ex or vi mode unless forced (e.g. by a window
         * size change).  This is because many curses implementations can't be
         * called twice in a single program.  Plus, it's faster.  If the editor
         * "leaves" vi to enter ex, when it exits ex we'll just fall back into
         * vi.
         */
        if (F_ISSET(sp, SC_SCR_EX))
                F_CLR(sp, SC_SCR_EX);

        /*
         * Fake leaving vi mode.
         *
         * Clear out the rest of the screen if we're in the middle of a split
         * screen.  Move to the last line in the current screen -- this makes
         * terminal scrolling happen naturally.  Note: *don't* move past the
         * end of the screen, as there are ex commands (e.g., :read ! cat file)
         * that don't want to.  Don't clear the info line, its contents may be
         * valid, e.g. :file|append.
         */
        if (F_ISSET(sp, SC_SCR_VI)) {
                F_CLR(sp, SC_SCR_VI);

                if (sp->q.cqe_next != (void *)&sp->wp->scrq) {
                        (void)wmove(win, RLNO(sp, sp->rows), 0);
                        wclrtobot(win);
                }
                (void)wmove(win, RLNO(sp, sp->rows) - 1, 0);
                wrefresh(win);
        }

        /* Enter the requested mode. */
        if (LF_ISSET(SC_EX)) {
                if (cl_ex_init(sp))
                        return (1);
                F_SET(clp, CL_IN_EX | CL_SCR_EX_INIT);

                /*
                 * If doing an ex screen for ex mode, move to the last line
                 * on the screen.
                 */
                if (F_ISSET(sp, SC_EX) && clp->cup != NULL)
                        tputs(tgoto(clp->cup,
                            0, O_VAL(sp, O_LINES) - 1), 1, cl_putchar);
        } else {
                if (cl_vi_init(sp))
                        return (1);
                F_CLR(clp, CL_IN_EX);
                F_SET(clp, CL_SCR_VI_INIT);
        }
        return (0);
}

/*
 * cl_quit --
 *      Shutdown the screens.
 *
 * PUBLIC: int cl_quit __P((GS *));
 */
int
cl_quit(gp)
        GS *gp;
{
        CL_PRIVATE *clp;
        int rval;

        rval = 0;
        clp = GCLP(gp);

        /*
         * If we weren't really running, ignore it.  This happens if the
         * screen changes size before we've called curses.
         */
        if (!F_ISSET(clp, CL_SCR_EX_INIT | CL_SCR_VI_INIT))
                return (0);

        /* Clean up the terminal mappings. */
        if (cl_term_end(gp))
                rval = 1;

        /* Really leave vi mode. */
        if (F_ISSET(clp, CL_STDIN_TTY) &&
            F_ISSET(clp, CL_SCR_VI_INIT) && cl_vi_end(gp))
                rval = 1;

        /* Really leave ex mode. */
        if (F_ISSET(clp, CL_STDIN_TTY) &&
            F_ISSET(clp, CL_SCR_EX_INIT) && cl_ex_end(gp))
                rval = 1;

        /*
         * If we were running ex when we quit, or we're using an implementation
         * of curses where endwin() doesn't get this right, restore the original
         * terminal modes.
         *
         * XXX
         * We always do this because it's too hard to figure out what curses
         * implementations get it wrong.  It may discard type-ahead characters
         * from the tty queue.
         */
        (void)tcsetattr(STDIN_FILENO, TCSADRAIN | TCSASOFT, &clp->orig);

        F_CLR(clp, CL_SCR_EX_INIT | CL_SCR_VI_INIT);
        return (rval);
}

/*
 * cl_vi_init --
 *      Initialize the curses vi screen.
 */
static int
cl_vi_init(sp)
        SCR *sp;
{
        CL_PRIVATE *clp;
        GS *gp;
        char *o_cols, *o_lines, *o_term, *ttype;

        gp = sp->gp;
        clp = CLP(sp);

        /* If already initialized, just set the terminal modes. */
        if (F_ISSET(clp, CL_SCR_VI_INIT))
                goto fast;

        /* Curses vi always reads from (and writes to) a terminal. */
        if (!F_ISSET(clp, CL_STDIN_TTY) || !isatty(STDOUT_FILENO)) {
                msgq(sp, M_ERR,
                    "016|Vi's standard input and output must be a terminal");
                return (1);
        }

        /* We'll need a terminal type. */
        if (opts_empty(sp, O_TERM, 0))
                return (1);
        ttype = O_STR(sp, O_TERM);

        /*
         * XXX
         * Changing the row/column and terminal values is done by putting them
         * into the environment, which is then read by curses.  What this loses
         * in ugliness, it makes up for in stupidity.  We can't simply put the
         * values into the environment ourselves, because in the presence of a
         * kernel mechanism for returning the window size, entering values into
         * the environment will screw up future screen resizing events, e.g. if
         * the user enters a :shell command and then resizes their window.  So,
         * if they weren't already in the environment, we make sure to delete
         * them immediately after setting them.
         *
         * XXX
         * Putting the TERM variable into the environment is necessary, even
         * though we're using newterm() here.  We may be using initscr() as
         * the underlying function.
         */
        o_term = getenv("TERM");
        cl_putenv("TERM", ttype, 0);
        o_lines = getenv("LINES");
        cl_putenv("LINES", NULL, (u_long)O_VAL(sp, O_LINES));
        o_cols = getenv("COLUMNS");
        cl_putenv("COLUMNS", NULL, (u_long)O_VAL(sp, O_COLUMNS));

        /*
         * We don't care about the SCREEN reference returned by newterm, we
         * never have more than one SCREEN at a time.
         *
         * XXX
         * The SunOS initscr() can't be called twice.  Don't even think about
         * using it.  It fails in subtle ways (e.g. select(2) on fileno(stdin)
         * stops working).  (The SVID notes that applications should only call
         * initscr() once.)
         *
         * XXX
         * The HP/UX newterm doesn't support the NULL first argument, so we
         * have to specify the terminal type.
         */
        errno = 0;
        if (newterm(ttype, stdout, stdin) == NULL) {
                if (errno)
                        msgq(sp, M_SYSERR, "%s", ttype);
                else
                        msgq(sp, M_ERR, "%s: unknown terminal type", ttype);
                return (1);
        }

        if (o_term == NULL)
                unsetenv("TERM");
        if (o_lines == NULL)
                unsetenv("LINES");
        if (o_cols == NULL)
                unsetenv("COLUMNS");

        /*
         * XXX
         * Someone got let out alone without adult supervision -- the SunOS
         * newterm resets the signal handlers.  There's a race, but it's not
         * worth closing.
         */
        (void)sig_init(sp->gp, sp);

        /*
         * We use raw mode.  What we want is 8-bit clean, however, signals
         * and flow control should continue to work.  Admittedly, it sounds
         * like cbreak, but it isn't.  Using cbreak() can get you additional
         * things like IEXTEN, which turns on flags like DISCARD and LNEXT.
         *
         * !!!
         * If raw isn't turning off echo and newlines, something's wrong.
         * However, it shouldn't hurt.
         */
        noecho();                       /* No character echo. */
        nonl();                         /* No CR/NL translation. */
        raw();                          /* 8-bit clean. */
        idlok(stdscr, 1);               /* Use hardware insert/delete line. */

        /* Put the cursor keys into application mode. */
        (void)keypad(stdscr, TRUE);

        /*
         * XXX
         * The screen TI sequence just got sent.  See the comment in
         * cl_funcs.c:cl_attr().
         */
        clp->ti_te = TI_SENT;

        /*
         * XXX
         * Historic implementations of curses handled SIGTSTP signals
         * in one of three ways.  They either:
         *
         *      1: Set their own handler, regardless.
         *      2: Did not set a handler if a handler was already installed.
         *      3: Set their own handler, but then called any previously set
         *         handler after completing their own cleanup.
         *
         * We don't try and figure out which behavior is in place, we force
         * it to SIG_DFL after initializing the curses interface, which means
         * that curses isn't going to take the signal.  Since curses isn't
         * reentrant (i.e., the whole curses SIGTSTP interface is a fantasy),
         * we're doing The Right Thing.
         */
        (void)signal(SIGTSTP, SIG_DFL);

        /*
         * If flow control was on, turn it back on.  Turn signals on.  ISIG
         * turns on VINTR, VQUIT, VDSUSP and VSUSP.   The main curses code
         * already installed a handler for VINTR.  We're going to disable the
         * other three.
         *
         * XXX
         * We want to use ^Y as a vi scrolling command.  If the user has the
         * DSUSP character set to ^Y (common practice) clean it up.  As it's
         * equally possible that the user has VDSUSP set to 'a', we disable
         * it regardless.  It doesn't make much sense to suspend vi at read,
         * so I don't think anyone will care.  Alternatively, we could look
         * it up in the table of legal command characters and turn it off if
         * it matches one.  VDSUSP wasn't in POSIX 1003.1-1990, so we test for
         * it.
         *
         * XXX
         * We don't check to see if the user had signals enabled originally.
         * If they didn't, it's unclear what we're supposed to do here, but
         * it's also pretty unlikely.
         */
        if (tcgetattr(STDIN_FILENO, &clp->vi_enter)) {
                msgq(sp, M_SYSERR, "tcgetattr");
                goto err;
        }
        if (clp->orig.c_iflag & IXON)
                clp->vi_enter.c_iflag |= IXON;
        if (clp->orig.c_iflag & IXOFF)
                clp->vi_enter.c_iflag |= IXOFF;

        clp->vi_enter.c_lflag |= ISIG;
#ifdef VDSUSP
        clp->vi_enter.c_cc[VDSUSP] = _POSIX_VDISABLE;
#endif
        clp->vi_enter.c_cc[VQUIT] = _POSIX_VDISABLE;
        clp->vi_enter.c_cc[VSUSP] = _POSIX_VDISABLE;

        /*
         * XXX
         * OSF/1 doesn't turn off the <discard>, <literal-next> or <status>
         * characters when curses switches into raw mode.  It should be OK
         * to do it explicitly for everyone.
         */
#ifdef VDISCARD
        clp->vi_enter.c_cc[VDISCARD] = _POSIX_VDISABLE;
#endif
#ifdef VLNEXT
        clp->vi_enter.c_cc[VLNEXT] = _POSIX_VDISABLE;
#endif
#ifdef VSTATUS
        clp->vi_enter.c_cc[VSTATUS] = _POSIX_VDISABLE;
#endif

        /* Initialize terminal based information. */
        if (cl_term_init(sp))
                goto err;

fast:   /* Set the terminal modes. */
        if (tcsetattr(STDIN_FILENO, TCSASOFT | TCSADRAIN, &clp->vi_enter)) {
                msgq(sp, M_SYSERR, "tcsetattr");
err:            (void)cl_vi_end(sp->gp);
                return (1);
        }
        return (0);
}

/*
 * cl_vi_end --
 *      Shutdown the vi screen.
 */
static int
cl_vi_end(gp)
        GS *gp;
{
        CL_PRIVATE *clp;

        clp = GCLP(gp);

        /* Restore the cursor keys to normal mode. */
        (void)keypad(stdscr, FALSE);

        /*
         * If we were running vi when we quit, scroll the screen up a single
         * line so we don't lose any information.
         *
         * Move to the bottom of the window (some endwin implementations don't
         * do this for you).
         */
        if (!F_ISSET(clp, CL_IN_EX)) {
                (void)move(0, 0);
                (void)deleteln();
                (void)move(LINES - 1, 0);
                (void)refresh();
        }

        cl_freecap(clp);

        /* End curses window. */
        (void)endwin();

        /*
         * XXX
         * The screen TE sequence just got sent.  See the comment in
         * cl_funcs.c:cl_attr().
         */
        clp->ti_te = TE_SENT;

        return (0);
}

/*
 * cl_ex_init --
 *      Initialize the ex screen.
 */
static int
cl_ex_init(sp)
        SCR *sp;
{
        CL_PRIVATE *clp;

        clp = CLP(sp);

        /* If already initialized, just set the terminal modes. */
        if (F_ISSET(clp, CL_SCR_EX_INIT))
                goto fast;

        /* If not reading from a file, we're done. */
        if (!F_ISSET(clp, CL_STDIN_TTY))
                return (0);

        /* Get the ex termcap/terminfo strings. */
        (void)cl_getcap(sp, "cup", &clp->cup);
        (void)cl_getcap(sp, "smso", &clp->smso);
        (void)cl_getcap(sp, "rmso", &clp->rmso);
        (void)cl_getcap(sp, "el", &clp->el);
        (void)cl_getcap(sp, "cuu1", &clp->cuu1);

        /* Enter_standout_mode and exit_standout_mode are paired. */
        if (clp->smso == NULL || clp->rmso == NULL) {
                if (clp->smso != NULL) {
                        free(clp->smso);
                        clp->smso = NULL;
                }
                if (clp->rmso != NULL) {
                        free(clp->rmso);
                        clp->rmso = NULL;
                }
        }

        /*
         * Turn on canonical mode, with normal input and output processing.
         * Start with the original terminal settings as the user probably
         * had them (including any local extensions) set correctly for the
         * current terminal.
         *
         * !!!
         * We can't get everything that we need portably; for example, ONLCR,
         * mapping <newline> to <carriage-return> on output isn't required
         * by POSIX 1003.1b-1993.  If this turns out to be a problem, then
         * we'll either have to play some games on the mapping, or we'll have
         * to make all ex printf's output \r\n instead of \n.
         */
        clp->ex_enter = clp->orig;
        clp->ex_enter.c_lflag  |= ECHO | ECHOE | ECHOK | ICANON | IEXTEN | ISIG;
#ifdef ECHOCTL
        clp->ex_enter.c_lflag |= ECHOCTL;
#endif
#ifdef ECHOKE
        clp->ex_enter.c_lflag |= ECHOKE;
#endif
        clp->ex_enter.c_iflag |= ICRNL;
        clp->ex_enter.c_oflag |= OPOST;
#ifdef ONLCR
        clp->ex_enter.c_oflag |= ONLCR;
#endif

fast:   if (tcsetattr(STDIN_FILENO, TCSADRAIN | TCSASOFT, &clp->ex_enter)) {
                msgq(sp, M_SYSERR, "tcsetattr");
                return (1);
        }
        return (0);
}

/*
 * cl_ex_end --
 *      Shutdown the ex screen.
 */
static int
cl_ex_end(gp)
        GS *gp;
{
        CL_PRIVATE *clp;

        clp = GCLP(gp);

        cl_freecap(clp);

        return (0);
}

/*
 * cl_getcap --
 *      Retrieve termcap/terminfo strings.
 *
 * PUBLIC: int cl_getcap __P((SCR *, char *, char **));
 */
int
cl_getcap(sp, name, elementp)
        SCR *sp;
        char *name, **elementp;
{
        size_t len;
        char *t;

        if ((t = tigetstr(name)) != NULL &&
            t != (char *)-1 && (len = strlen(t)) != 0) {
                MALLOC_RET(sp, *elementp, char *, len + 1);
                memmove(*elementp, t, len + 1);
        }
        return (0);
}

/*
 * cl_freecap --
 *      Free any allocated termcap/terminfo strings.
 */
static void
cl_freecap(clp)
        CL_PRIVATE *clp;
{
        if (clp->el != NULL) {
                free(clp->el);
                clp->el = NULL;
        }
        if (clp->cup != NULL) {
                free(clp->cup);
                clp->cup = NULL;
        }
        if (clp->cuu1 != NULL) {
                free(clp->cuu1);
                clp->cuu1 = NULL;
        }
        if (clp->rmso != NULL) {
                free(clp->rmso);
                clp->rmso = NULL;
        }
        if (clp->smso != NULL) {
                free(clp->smso);
                clp->smso = NULL;
        }
}

/*
 * cl_putenv --
 *      Put a value into the environment.
 */
static int
cl_putenv(name, str, value)
        char *name, *str;
        u_long value;

{
        char buf[40];

        if (str == NULL) {
                (void)snprintf(buf, sizeof(buf), "%lu", value);
                return (setenv(name, buf, 1));
        } else
                return (setenv(name, str, 1));
}