/* $OpenBSD: undo.c,v 1.44 2007/09/16 20:34:18 kjell Exp $ */
/*
* Copyright (c) 2002 Vincent Labrecque <vincent@openbsd.org>
* Copyright (c) 2005, 2006 Kjell Wooding <kjell@openbsd.org>
* 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.
*
* 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.
*/
#include "def.h"
#include "kbd.h"
#define MAX_FREE_RECORDS 32
/*
* Local variables
*/
static LIST_HEAD(, undo_rec) undo_free;
static int undo_free_num;
static int boundary_flag = TRUE;
static int undo_enable_flag = TRUE;
/*
* Local functions
*/
static int find_dot(struct line *, int);
static int find_lo(int, struct line **, int *, int *);
static struct undo_rec *new_undo_record(void);
static int drop_oldest_undo_record(void);
/*
* find_dot, find_lo()
*
* Find an absolute dot in the buffer from a line/offset pair, and vice-versa.
*
* Since lines can be deleted while they are referenced by undo record, we
* need to have an absolute dot to have something reliable.
*/
static int
find_dot(struct line *lp, int off)
{
int count = 0;
struct line *p;
for (p = curbp->b_headp; p != lp; p = lforw(p)) {
if (count != 0) {
if (p == curbp->b_headp) {
ewprintf("Error: Undo stuff called with a"
"nonexistent line");
return (FALSE);
}
}
count += llength(p) + 1;
}
count += off;
return (count);
}
static int
find_lo(int pos, struct line **olp, int *offset, int *lnum)
{
struct line *p;
int lineno;
p = curbp->b_headp;
lineno = 0;
while (pos > llength(p)) {
pos -= llength(p) + 1;
if ((p = lforw(p)) == curbp->b_headp) {
*olp = NULL;
*offset = 0;
return (FALSE);
}
lineno++;
}
*olp = p;
*offset = pos;
*lnum = lineno;
return (TRUE);
}
static struct undo_rec *
new_undo_record(void)
{
struct undo_rec *rec;
rec = LIST_FIRST(&undo_free);
if (rec != NULL) {
LIST_REMOVE(rec, next); /* Remove it from the free-list */
undo_free_num--;
} else {
if ((rec = malloc(sizeof(*rec))) == NULL)
panic("Out of memory in undo code (record)");
}
memset(rec, 0, sizeof(struct undo_rec));
return (rec);
}
void
free_undo_record(struct undo_rec *rec)
{
static int initialised = 0;
/*
* On the first run, do initialisation of the free list.
*/
if (initialised == 0) {
LIST_INIT(&undo_free);
initialised = 1;
}
if (rec->content != NULL) {
free(rec->content);
rec->content = NULL;
}
if (undo_free_num >= MAX_FREE_RECORDS) {
free(rec);
return;
}
undo_free_num++;
LIST_INSERT_HEAD(&undo_free, rec, next);
}
/*
* Drop the oldest undo record in our list. Return 1 if we could remove it,
* 0 if the undo list was empty.
*/
static int
drop_oldest_undo_record(void)
{
struct undo_rec *rec;
rec = LIST_END(&curbp->b_undo);
if (rec != NULL) {
undo_free_num--;
LIST_REMOVE(rec, next);
free_undo_record(rec);
return (1);
}
return (0);
}
static int
lastrectype(void)
{
struct undo_rec *rec;
if ((rec = LIST_FIRST(&curbp->b_undo)) != NULL)
return (rec->type);
return (0);
}
/*
* Returns TRUE if undo is enabled, FALSE otherwise.
*/
int
undo_enabled(void)
{
return (undo_enable_flag);
}
/*
* undo_enable(TRUE/FALSE) will enable / disable the undo mechanism.
* Returns TRUE if previously enabled, FALSE otherwise.
*/
int
undo_enable(int on)
{
int pon = undo_enable_flag;
undo_enable_flag = on;
return (pon);
}
/*
* If undo is enabled, then:
* undo_boundary_enable(FALS) stops recording undo boundaries between actions.
* undo_boundary_enable(TRUE) enables undo boundaries.
* If undo is disabled, this function has no effect.
*/
void
undo_boundary_enable(int flag)
{
if (undo_enable_flag == TRUE)
boundary_flag = flag;
}
/*
* Record an undo boundary, unless boundary_flag == FALSE.
* Does nothing if previous undo entry is already a boundary or 'modified' flag.
*/
void
undo_add_boundary(void)
{
struct undo_rec *rec;
int last;
if (boundary_flag == FALSE)
return;
last = lastrectype();
if (last == BOUNDARY || last == MODIFIED)
return;
rec = new_undo_record();
rec->type = BOUNDARY;
LIST_INSERT_HEAD(&curbp->b_undo, rec, next);
return;
}
/*
* Record an undo "modified" boundary
*/
void
undo_add_modified(void)
{
struct undo_rec *rec;
rec = new_undo_record();
rec->type = MODIFIED;
LIST_INSERT_HEAD(&curbp->b_undo, rec, next);
return;
}
int
undo_add_insert(struct line *lp, int offset, int size)
{
struct region reg;
struct undo_rec *rec;
int pos;
if (undo_enable_flag == FALSE)
return (TRUE);
reg.r_linep = lp;
reg.r_offset = offset;
reg.r_size = size;
pos = find_dot(lp, offset);
/*
* We try to reuse the last undo record to `compress' things.
*/
rec = LIST_FIRST(&curbp->b_undo);
if (rec != NULL && rec->type == INSERT) {
if (rec->pos + rec->region.r_size == pos) {
rec->region.r_size += reg.r_size;
return (TRUE);
}
}
/*
* We couldn't reuse the last undo record, so prepare a new one.
*/
rec = new_undo_record();
rec->pos = pos;
rec->type = INSERT;
memmove(&rec->region, ®, sizeof(struct region));
rec->content = NULL;
undo_add_boundary();
LIST_INSERT_HEAD(&curbp->b_undo, rec, next);
return (TRUE);
}
/*
* This of course must be done _before_ the actual deletion is done.
*/
int
undo_add_delete(struct line *lp, int offset, int size)
{
struct region reg;
struct undo_rec *rec;
int pos;
if (undo_enable_flag == FALSE)
return (TRUE);
reg.r_linep = lp;
reg.r_offset = offset;
reg.r_size = size;
pos = find_dot(lp, offset);
if (offset == llength(lp)) /* if it's a newline... */
undo_add_boundary();
else if ((rec = LIST_FIRST(&curbp->b_undo)) != NULL) {
/*
* Separate this command from the previous one if we're not
* just before the previous record...
*/
if (rec->type == DELETE) {
if (rec->pos - rec->region.r_size != pos)
undo_add_boundary();
}
}
rec = new_undo_record();
rec->pos = pos;
rec->type = DELETE;
memmove(&rec->region, ®, sizeof(struct region));
do {
rec->content = malloc(reg.r_size + 1);
} while ((rec->content == NULL) && drop_oldest_undo_record());
if (rec->content == NULL)
panic("Out of memory");
region_get_data(®, rec->content, reg.r_size);
if (lastrectype() != DELETE)
undo_add_boundary();
LIST_INSERT_HEAD(&curbp->b_undo, rec, next);
return (TRUE);
}
/*
* This of course must be called before the change takes place.
*/
int
undo_add_change(struct line *lp, int offset, int size)
{
if (undo_enable_flag == FALSE)
return (TRUE);
undo_add_boundary();
boundary_flag = FALSE;
undo_add_delete(lp, offset, size);
undo_add_insert(lp, offset, size);
boundary_flag = TRUE;
undo_add_boundary();
return (TRUE);
}
/*
* Show the undo records for the current buffer in a new buffer.
*/
/* ARGSUSED */
int
undo_dump(int f, int n)
{
struct undo_rec *rec;
struct buffer *bp;
struct mgwin *wp;
char buf[4096], tmp[1024];
int num;
/*
* Prepare the buffer for insertion.
*/
if ((bp = bfind("*undo*", TRUE)) == NULL)
return (FALSE);
bp->b_flag |= BFREADONLY;
bclear(bp);
popbuf(bp);
for (wp = wheadp; wp != NULL; wp = wp->w_wndp) {
if (wp->w_bufp == bp) {
wp->w_dotp = bp->b_headp;
wp->w_doto = 0;
}
}
num = 0;
for (rec = LIST_FIRST(&curbp->b_undo); rec != NULL;
rec = LIST_NEXT(rec, next)) {
num++;
snprintf(buf, sizeof(buf),
"%d:\t %s at %d ", num,
(rec->type == DELETE) ? "DELETE":
(rec->type == INSERT) ? "INSERT":
(rec->type == BOUNDARY) ? "----" :
(rec->type == MODIFIED) ? "MODIFIED": "UNKNOWN",
rec->pos);
if (rec->content) {
(void)strlcat(buf, "\"", sizeof(buf));
snprintf(tmp, sizeof(tmp), "%.*s", rec->region.r_size,
rec->content);
(void)strlcat(buf, tmp, sizeof(buf));
(void)strlcat(buf, "\"", sizeof(buf));
}
snprintf(tmp, sizeof(tmp), " [%d]", rec->region.r_size);
if (strlcat(buf, tmp, sizeof(buf)) >= sizeof(buf)) {
ewprintf("Undo record too large. Aborted.");
return (FALSE);
}
addlinef(bp, "%s", buf);
}
return (TRUE);
}
/*
* After the user did action1, then action2, then action3:
*
* [action3] <--- Undoptr
* [action2]
* [action1]
* ------
* [undo]
*
* After undo:
*
* [undo of action3]
* [action2] <--- Undoptr
* [action1]
* ------
* [undo]
*
* After another undo:
*
*
* [undo of action2]
* [undo of action3]
* [action1] <--- Undoptr
* ------
* [undo]
*
* Note that the "undo of actionX" have no special meaning. Only when
* we undo a deletion, the insertion will be recorded just as if it
* was typed on the keyboard. Resulting in the inverse operation being
* saved in the list.
*
* If undoptr reaches the bottom of the list, or if we moved between
* two undo actions, we make it point back at the topmost record. This is
* how we handle redoing.
*/
/* ARGSUSED */
int
undo(int f, int n)
{
struct undo_rec *ptr, *nptr;
int done, rval;
struct line *lp;
int offset, save, dot;
static int nulled = FALSE;
int lineno;
dot = find_dot(curwp->w_dotp, curwp->w_doto);
ptr = curbp->b_undoptr;
/* if we moved, make ptr point back to the top of the list */
if ((ptr == NULL && nulled == TRUE) || curbp->b_undopos != dot) {
ptr = LIST_FIRST(&curbp->b_undo);
nulled = TRUE;
}
rval = TRUE;
while (n--) {
/* if we have a spurious boundary, free it and move on.... */
while (ptr && ptr->type == BOUNDARY) {
nptr = LIST_NEXT(ptr, next);
LIST_REMOVE(ptr, next);
free_undo_record(ptr);
ptr = nptr;
}
/*
* Ptr is NULL, but on the next run, it will point to the
* top again, redoing all stuff done in the buffer since
* its creation.
*/
if (ptr == NULL) {
ewprintf("No further undo information");
rval = FALSE;
nulled = TRUE;
break;
}
nulled = FALSE;
/*
* Loop while we don't get a boundary specifying we've
* finished the current action...
*/
undo_add_boundary();
save = boundary_flag;
boundary_flag = FALSE;
done = 0;
do {
/*
* Move to where this has to apply
*
* Boundaries (and the modified flag) are put as
* position 0 (to save lookup time in find_dot)
* so we must not move there...
*/
if (ptr->type != BOUNDARY && ptr->type != MODIFIED) {
if (find_lo(ptr->pos, &lp,
&offset, &lineno) == FALSE) {
ewprintf("Internal error in Undo!");
rval = FALSE;
break;
}
curwp->w_dotp = lp;
curwp->w_doto = offset;
curwp->w_markline = curwp->w_dotline;
curwp->w_dotline = lineno;
}
/*
* Do operation^-1
*/
switch (ptr->type) {
case INSERT:
ldelete(ptr->region.r_size, KNONE);
break;
case DELETE:
region_put_data(ptr->content,
ptr->region.r_size);
break;
case BOUNDARY:
done = 1;
break;
case MODIFIED:
curbp->b_flag &= ~BFCHG;
break;
default:
break;
}
/* And move to next record */
ptr = LIST_NEXT(ptr, next);
} while (ptr != NULL && !done);
boundary_flag = save;
undo_add_boundary();
ewprintf("Undo!");
}
/*
* Record where we are. (we have to save our new position at the end
* since we change the dot when undoing....)
*/
curbp->b_undoptr = ptr;
curbp->b_undopos = find_dot(curwp->w_dotp, curwp->w_doto);
return (rval);
}