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git/xdiff/xemit.c

330 lines
8.0 KiB

/*
* LibXDiff by Davide Libenzi ( File Differential Library )
* Copyright (C) 2003 Davide Libenzi
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/>.
*
* Davide Libenzi <davidel@xmailserver.org>
*
*/
#include "xinclude.h"
static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
*rec = xdf->recs[ri]->ptr;
return xdf->recs[ri]->size;
}
static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
long size, psize = strlen(pre);
char const *rec;
size = xdl_get_rec(xdf, ri, &rec);
if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
return -1;
}
return 0;
}
/*
* Starting at the passed change atom, find the latest change atom to be included
* inside the differential hunk according to the specified configuration.
* Also advance xscr if the first changes must be discarded.
*/
xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
{
xdchange_t *xch, *xchp, *lxch;
long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
long max_ignorable = xecfg->ctxlen;
unsigned long ignored = 0; /* number of ignored blank lines */
/* remove ignorable changes that are too far before other changes */
for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
xch = xchp->next;
if (xch == NULL ||
xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
*xscr = xch;
}
if (*xscr == NULL)
return NULL;
lxch = *xscr;
for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
long distance = xch->i1 - (xchp->i1 + xchp->chg1);
if (distance > max_common)
break;
if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
lxch = xch;
ignored = 0;
} else if (distance < max_ignorable && xch->ignore) {
ignored += xch->chg2;
} else if (lxch != xchp &&
xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
break;
} else if (!xch->ignore) {
lxch = xch;
ignored = 0;
} else {
ignored += xch->chg2;
}
}
return lxch;
}
static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
{
if (len > 0 &&
(isalpha((unsigned char)*rec) || /* identifier? */
*rec == '_' || /* also identifier? */
*rec == '$')) { /* identifiers from VMS and other esoterico */
if (len > sz)
len = sz;
while (0 < len && isspace((unsigned char)rec[len - 1]))
len--;
memcpy(buf, rec, len);
return len;
}
return -1;
}
static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
char *buf, long sz)
{
const char *rec;
long len = xdl_get_rec(xdf, ri, &rec);
if (!xecfg->find_func)
return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
}
static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
{
char dummy[1];
return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
}
struct func_line {
long len;
char buf[80];
};
static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
struct func_line *func_line, long start, long limit)
{
long l, size, step = (start > limit) ? -1 : 1;
char *buf, dummy[1];
buf = func_line ? func_line->buf : dummy;
size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
if (len >= 0) {
if (func_line)
func_line->len = len;
return l;
}
}
return -1;
}
static int is_empty_rec(xdfile_t *xdf, long ri)
{
const char *rec;
long len = xdl_get_rec(xdf, ri, &rec);
while (len > 0 && XDL_ISSPACE(*rec)) {
rec++;
len--;
}
return !len;
}
int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
xdemitconf_t const *xecfg) {
long s1, s2, e1, e2, lctx;
xdchange_t *xch, *xche;
long funclineprev = -1;
struct func_line func_line = { 0 };
for (xch = xscr; xch; xch = xche->next) {
xdchange_t *xchp = xch;
xche = xdl_get_hunk(&xch, xecfg);
if (!xch)
break;
pre_context_calculation:
s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
long fs1, i1 = xch->i1;
/* Appended chunk? */
if (i1 >= xe->xdf1.nrec) {
long i2 = xch->i2;
/*
* We don't need additional context if
* a whole function was added.
*/
while (i2 < xe->xdf2.nrec) {
if (is_func_rec(&xe->xdf2, xecfg, i2))
goto post_context_calculation;
i2++;
}
/*
* Otherwise get more context from the
* pre-image.
*/
i1 = xe->xdf1.nrec - 1;
}
fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
!is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
fs1--;
if (fs1 < 0)
fs1 = 0;
if (fs1 < s1) {
s2 = XDL_MAX(s2 - (s1 - fs1), 0);
s1 = fs1;
/*
* Did we extend context upwards into an
* ignored change?
*/
while (xchp != xch &&
xchp->i1 + xchp->chg1 <= s1 &&
xchp->i2 + xchp->chg2 <= s2)
xchp = xchp->next;
/* If so, show it after all. */
if (xchp != xch) {
xch = xchp;
goto pre_context_calculation;
}
}
}
post_context_calculation:
lctx = xecfg->ctxlen;
lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
e1 = xche->i1 + xche->chg1 + lctx;
e2 = xche->i2 + xche->chg2 + lctx;
if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
long fe1 = get_func_line(xe, xecfg, NULL,
xche->i1 + xche->chg1,
xe->xdf1.nrec);
while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
fe1--;
if (fe1 < 0)
fe1 = xe->xdf1.nrec;
if (fe1 > e1) {
e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
e1 = fe1;
}
/*
* Overlap with next change? Then include it
* in the current hunk and start over to find
* its new end.
*/
if (xche->next) {
long l = XDL_MIN(xche->next->i1,
xe->xdf1.nrec - 1);
if (l - xecfg->ctxlen <= e1 ||
get_func_line(xe, xecfg, NULL, l, e1) < 0) {
xche = xche->next;
goto post_context_calculation;
}
}
}
/*
* Emit current hunk header.
*/
if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
get_func_line(xe, xecfg, &func_line,
s1 - 1, funclineprev);
funclineprev = s1 - 1;
}
if (!(xecfg->flags & XDL_EMIT_NO_HUNK_HDR) &&
xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
func_line.buf, func_line.len, ecb) < 0)
return -1;
/*
* Emit pre-context.
*/
for (; s2 < xch->i2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
return -1;
for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
/*
* Merge previous with current change atom.
*/
for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
return -1;
/*
* Removes lines from the first file.
*/
for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
return -1;
/*
* Adds lines from the second file.
*/
for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
return -1;
if (xch == xche)
break;
s1 = xch->i1 + xch->chg1;
s2 = xch->i2 + xch->chg2;
}
/*
* Emit post-context.
*/
for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
return -1;
}
return 0;
}