usr.bin/vi/mark.c

/*-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  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, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#ifndef lint
static char sccsid[] = "@(#)mark.c      8.12 (Berkeley) 12/27/93";
#endif /* not lint */

#include <sys/types.h>

#include <errno.h>
#include <stdlib.h>
#include <string.h>

#include "vi.h"

static MARK *mark_find __P((SCR *, EXF *, ARG_CHAR_T));

/*
 * Marks are maintained in a key sorted doubly linked list.  We can't
 * use arrays because we have no idea how big an index key could be.
 * The underlying assumption is that users don't have more than, say,
 * 10 marks at any one time, so this will be is fast enough.
 *
 * Marks are fixed, and modifications to the line don't update the mark's
 * position in the line.  This can be hard.  If you add text to the line,
 * place a mark in that text, undo the addition and use ` to move to the
 * mark, the location will have disappeared.  It's tempting to try to adjust
 * the mark with the changes in the line, but this is hard to do, especially
 * if we've given the line to v_ntext.c:v_ntext() for editing.  Historic vi
 * would move to the first non-blank on the line when the mark location was
 * past the end of the line.  This can be complicated by deleting to a mark
 * that has disappeared using the ` command.  Historic vi vi treated this as
 * a line-mode motion and deleted the line.  This implementation complains to
 * the user.
 *
 * In historic vi, marks returned if the operation was undone, unless the
 * mark had been subsequently reset.  Tricky.  This is hard to start with,
 * but in the presence of repeated undo it gets nasty.  When a line is
 * deleted, we delete (and log) any marks on that line.  An undo will create
 * the mark.  Any mark creations are noted as to whether the user created
 * it or if it was created by an undo.  The former cannot be reset by another
 * undo, but the latter may.
 *
 * All of these routines translate ABSMARK2 to ABSMARK1.  Setting either of
 * the absolute mark locations sets both, so that "m'" and "m`" work like
 * they, ah, for lack of a better word, "should".
 */

/*
 * mark_init --
 *      Set up the marks.
 */
int
mark_init(sp, ep)
        SCR *sp;
        EXF *ep;
{
        MARK *mp;

        /*
         * Make sure the marks have been set up.  If they
         * haven't, do so, and create the absolute mark.
         */
        MALLOC_RET(sp, mp, MARK *, sizeof(MARK));
        mp->lno = 1;
        mp->cno = 0;
        mp->name = ABSMARK1;
        mp->flags = 0;
        LIST_INSERT_HEAD(&ep->marks, mp, q);
        return (0);
}

/*
 * mark_end --
 *      Free up the marks.
 */
int
mark_end(sp, ep)
        SCR *sp;
        EXF *ep;
{
        MARK *mp;

        while ((mp = ep->marks.lh_first) != NULL) {
                LIST_REMOVE(mp, q);
                FREE(mp, sizeof(MARK));
        }
        return (0);
}

/*
 * mark_get --
 *      Get the location referenced by a mark.
 */
MARK *
mark_get(sp, ep, key)
        SCR *sp;
        EXF *ep;
        ARG_CHAR_T key;
{
        MARK *mp;
        size_t len;
        char *p;

        if (key == ABSMARK2)
                key = ABSMARK1;

        mp = mark_find(sp, ep, key);
        if (mp == NULL || mp->name != key) {
                msgq(sp, M_BERR, "Mark %s: not set.", charname(sp, key));
                return (NULL);
        }
        if (F_ISSET(mp, MARK_DELETED)) {
                msgq(sp, M_BERR,
                    "Mark %s: the line was deleted.", charname(sp, key));
                return (NULL);
        }
        if ((p = file_gline(sp, ep, mp->lno, &len)) == NULL ||
            mp->cno > len || mp->cno == len && len != 0) {
                msgq(sp, M_BERR, "Mark %s: cursor position no longer exists.",
                    charname(sp, key));
                return (NULL);
        }
        return (mp);
}

/*
 * mark_set --
 *      Set the location referenced by a mark.
 */
int
mark_set(sp, ep, key, value, userset)
        SCR *sp;
        EXF *ep;
        ARG_CHAR_T key;
        MARK *value;
        int userset;
{
        MARK *mp, *mt;

        if (key == ABSMARK2)
                key = ABSMARK1;

        /*
         * The rules are simple.  If the user is setting a mark (if it's a
         * new mark this is always true), it always happens.  If not, it's
         * an undo, and we set it if it's not already set or if it was set
         * by a previous undo.
         */
        mp = mark_find(sp, ep, key);
        if (mp == NULL || mp->name != key) {
                MALLOC_RET(sp, mt, MARK *, sizeof(MARK));
                if (mp == NULL) {
                        LIST_INSERT_HEAD(&ep->marks, mt, q);
                } else
                        LIST_INSERT_AFTER(mp, mt, q);
                mp = mt;
        } else if (!userset &&
            !F_ISSET(mp, MARK_DELETED) && F_ISSET(mp, MARK_USERSET))
                return (0);

        mp->lno = value->lno;
        mp->cno = value->cno;
        mp->name = key;
        mp->flags = userset ? MARK_USERSET : 0;
        return (0);
}

/*
 * mark_find --
 *      Find the requested mark, or, the slot immediately before
 *      where it would go.
 */
static MARK *
mark_find(sp, ep, key)
        SCR *sp;
        EXF *ep;
        ARG_CHAR_T key;
{
        MARK *mp, *lastmp;

        /*
         * Return the requested mark or the slot immediately before
         * where it should go.
         */
        for (lastmp = NULL, mp = ep->marks.lh_first;
            mp != NULL; lastmp = mp, mp = mp->q.le_next)
                if (mp->name >= key)
                        return (mp->name == key ? mp : lastmp);
        return (lastmp);
}

/*
 * mark_insdel --
 *      Update the marks based on an insertion or deletion.
 */
void
mark_insdel(sp, ep, op, lno)
        SCR *sp;
        EXF *ep;
        enum operation op;
        recno_t lno;
{
        MARK *mp;

        switch (op) {
        case LINE_APPEND:
                return;
        case LINE_DELETE:
                for (mp = ep->marks.lh_first; mp != NULL; mp = mp->q.le_next)
                        if (mp->lno >= lno)
                                if (mp->lno == lno) {
                                        F_SET(mp, MARK_DELETED);
                                        (void)log_mark(sp, ep, mp);
                                } else
                                        --mp->lno;
                return;
        case LINE_INSERT:
                for (mp = ep->marks.lh_first; mp != NULL; mp = mp->q.le_next)
                        if (mp->lno >= lno)
                                ++mp->lno;
                return;
        case LINE_RESET:
                return;
        }
        /* NOTREACHED */
}