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/*-
* 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[] = "@(#)v_undo.c 8.6 (Berkeley) 1/8/94";
#endif /* not lint */
#include <sys/types.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "vi.h"
#include "vcmd.h"
/*
* v_Undo -- U
* Undo changes to this line.
*/
int
v_Undo(sp, ep, vp, fm, tm, rp)
SCR *sp;
EXF *ep;
VICMDARG *vp;
MARK *fm, *tm, *rp;
{
/*
* Historically, U reset the cursor to the first column in the line
* (not the first non-blank). This seems a bit non-intuitive, but,
* considering that we may have undone multiple changes, anything
* else (including the cursor position stored in the logging records)
* is going to appear random.
*/
rp->lno = fm->lno;
rp->cno = 0;
/*
* !!!
* Set up the flags so that an immediately subsequent 'u' will roll
* forward, instead of backward. In historic vi, a 'u' following a
* 'U' redid all of the changes to the line. Given that the user has
* explicitly discarded those changes by entering 'U', it seems likely
* that the user wants something between the original and end forms of
* the line, so starting to replay the changes seems the best way to
* get to there.
*/
F_SET(ep, F_UNDO);
ep->lundo = BACKWARD;
return (log_setline(sp, ep));
}
/*
* v_undo -- u
* Undo the last change.
*/
int
v_undo(sp, ep, vp, fm, tm, rp)
SCR *sp;
EXF *ep;
VICMDARG *vp;
MARK *fm, *tm, *rp;
{
/* Set the command count. */
VIP(sp)->u_ccnt = sp->ccnt;
/*
* !!!
* In historic vi, 'u' toggled between "undo" and "redo", i.e. 'u'
* undid the last undo. However, if there has been a change since
* the last undo/redo, we always do an undo. To make this work when
* the user can undo multiple operations, we leave the old semantic
* unchanged, but make '.' after a 'u' do another undo/redo operation.
* This has two problems.
*
* The first is that 'u' didn't set '.' in historic vi. So, if a
* user made a change, realized it was in the wrong place, does a
* 'u' to undo it, moves to the right place and then does '.', the
* change was reapplied. To make this work, we only apply the '.'
* to the undo command if it's the command immediately following an
* undo command. See vi/vi.c:getcmd() for the details.
*
* The second is that the traditional way to view the numbered cut
* buffers in vi was to enter the commands "1pu.u.u.u. which will
* no longer work because the '.' immediately follows the 'u' command.
* Since we provide a much better method of viewing buffers, and
* nobody can think of a better way of adding in multiple undo, this
* remains broken.
*/
if (!F_ISSET(ep, F_UNDO)) {
F_SET(ep, F_UNDO);
ep->lundo = BACKWARD;
} else if (!F_ISSET(vp, VC_ISDOT))
ep->lundo = ep->lundo == BACKWARD ? FORWARD : BACKWARD;
switch (ep->lundo) {
case BACKWARD:
return (log_backward(sp, ep, rp));
case FORWARD:
return (log_forward(sp, ep, rp));
default:
abort();
}
/* NOTREACHED */
}
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