[thirdparty/git.git] / xdiff / xemit.c

/*
 *  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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  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);
}

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) {
		xche = xdl_get_hunk(&xch, xecfg);
		if (!xch)
			break;

		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) {
				char dummy[1];
				long i2 = xch->i2;

				/*
				 * We don't need additional context if
				 * a whole function was added.
				 */
				while (i2 < xe->xdf2.nrec) {
					if (match_func_rec(&xe->xdf2, xecfg, i2,
						dummy, sizeof(dummy)) >= 0)
						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);
			if (fs1 < 0)
				fs1 = 0;
			if (fs1 < s1) {
				s2 -= s1 - fs1;
				s1 = fs1;
			}
		}

 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 += fe1 - e1;
				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 (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;
}
Commit	Line	Data
3443546f LT	1	/*
	2	* LibXDiff by Davide Libenzi ( File Differential Library )
	3	* Copyright (C) 2003 Davide Libenzi
	4	*
	5	* This library is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU Lesser General Public
	7	* License as published by the Free Software Foundation; either
	8	* version 2.1 of the License, or (at your option) any later version.
	9	*
	10	* This library is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* Lesser General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU Lesser General Public
	16	* License along with this library; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*
	19	* Davide Libenzi <davidel@xmailserver.org>
	20	*
	21	*/
	22
	23	#include "xinclude.h"
	24
3443546f LT	25	static long xdl_get_rec(xdfile_t xdf, long ri, char const *rec) {
	26
	27	*rec = xdf->recs[ri]->ptr;
	28
	29	return xdf->recs[ri]->size;
	30	}
	31
	32
	33	static int xdl_emit_record(xdfile_t xdf, long ri, char const pre, xdemitcb_t *ecb) {
	34	long size, psize = strlen(pre);
	35	char const *rec;
	36
	37	size = xdl_get_rec(xdf, ri, &rec);
	38	if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
	39
	40	return -1;
	41	}
	42
	43	return 0;
	44	}
	45
	46
	47	/*
	48	* Starting at the passed change atom, find the latest change atom to be included
	49	* inside the differential hunk according to the specified configuration.
36617af7	50	* Also advance xscr if the first changes must be discarded.
3443546f	51	*/
36617af7 AP	52	xdchange_t xdl_get_hunk(xdchange_t xscr, xdemitconf_t const xecfg)
	53	{
	54	xdchange_t xch, xchp, *lxch;
6d0e674a	55	long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
36617af7 AP	56	long max_ignorable = xecfg->ctxlen;
	57	unsigned long ignored = 0; /* number of ignored blank lines */
	58
	59	/* remove ignorable changes that are too far before other changes */
	60	for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
	61	xch = xchp->next;
	62
	63	if (xch == NULL \|\|
	64	xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
	65	*xscr = xch;
	66	}
	67
	68	if (*xscr == NULL)
	69	return NULL;
	70
	71	lxch = *xscr;
3443546f	72
36617af7 AP	73	for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
	74	long distance = xch->i1 - (xchp->i1 + xchp->chg1);
	75	if (distance > max_common)
3443546f LT	76	break;
3443546f LT	77
36617af7 AP	78	if (distance < max_ignorable && (!xch->ignore \|\| lxch == xchp)) {
	79	lxch = xch;
	80	ignored = 0;
	81	} else if (distance < max_ignorable && xch->ignore) {
	82	ignored += xch->chg2;
	83	} else if (lxch != xchp &&
	84	xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
	85	break;
	86	} else if (!xch->ignore) {
	87	lxch = xch;
	88	ignored = 0;
	89	} else {
	90	ignored += xch->chg2;
	91	}
	92	}
	93
	94	return lxch;
3443546f LT	95	}
	96
	97
f258475a JH	98	static long def_ff(const char rec, long len, char buf, long sz, void *priv)
	99	{
	100	if (len > 0 &&
	101	(isalpha((unsigned char)rec) \|\| / identifier? */
c01499ef	102	rec == '_' \|\| / also identifier? */
f258475a JH	103	rec == '$')) { / identifiers from VMS and other esoterico */
	104	if (len > sz)
	105	len = sz;
	106	while (0 < len && isspace((unsigned char)rec[len - 1]))
	107	len--;
	108	memcpy(buf, rec, len);
	109	return len;
	110	}
	111	return -1;
	112	}
	113
ff2981f7 RS	114	static long match_func_rec(xdfile_t xdf, xdemitconf_t const xecfg, long ri,
	115	char *buf, long sz)
	116	{
	117	const char *rec;
	118	long len = xdl_get_rec(xdf, ri, &rec);
	119	if (!xecfg->find_func)
	120	return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
	121	return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
	122	}
	123
f99f4b36 RS	124	struct func_line {
	125	long len;
	126	char buf[80];
	127	};
	128
14937c2c	129	static long get_func_line(xdfenv_t xe, xdemitconf_t const xecfg,
f99f4b36 RS	130	struct func_line *func_line, long start, long limit)
f99f4b36 RS	131	{
14937c2c RS	132	long l, size, step = (start > limit) ? -1 : 1;
14937c2c RS	133	char *buf, dummy[1];
f99f4b36	134
14937c2c RS	135	buf = func_line ? func_line->buf : dummy;
	136	size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
	137
	138	for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
ff2981f7	139	long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
f99f4b36	140	if (len >= 0) {
14937c2c RS	141	if (func_line)
	142	func_line->len = len;
	143	return l;
f99f4b36 RS	144	}
f99f4b36 RS	145	}
14937c2c	146	return -1;
f99f4b36 RS	147	}
f99f4b36 RS	148
392f6d31 RS	149	static int is_empty_rec(xdfile_t *xdf, long ri)
	150	{
	151	const char *rec;
	152	long len = xdl_get_rec(xdf, ri, &rec);
	153
	154	while (len > 0 && XDL_ISSPACE(*rec)) {
	155	rec++;
	156	len--;
	157	}
	158	return !len;
	159	}
	160
3443546f LT	161	int xdl_emit_diff(xdfenv_t xe, xdchange_t xscr, xdemitcb_t *ecb,
	162	xdemitconf_t const *xecfg) {
	163	long s1, s2, e1, e2, lctx;
	164	xdchange_t xch, xche;
c099789b	165	long funclineprev = -1;
f99f4b36	166	struct func_line func_line = { 0 };
3443546f	167
8e24cbae	168	for (xch = xscr; xch; xch = xche->next) {
36617af7 AP	169	xche = xdl_get_hunk(&xch, xecfg);
	170	if (!xch)
	171	break;
3443546f LT	172
	173	s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
	174	s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
	175
14937c2c	176	if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
6d5badb2 RS	177	long fs1, i1 = xch->i1;
	178
	179	/* Appended chunk? */
	180	if (i1 >= xe->xdf1.nrec) {
	181	char dummy[1];
392f6d31	182	long i2 = xch->i2;
6d5badb2 RS	183
	184	/*
	185	* We don't need additional context if
540d3eb0	186	* a whole function was added.
6d5badb2	187	*/
540d3eb0 VN	188	while (i2 < xe->xdf2.nrec) {
	189	if (match_func_rec(&xe->xdf2, xecfg, i2,
	190	dummy, sizeof(dummy)) >= 0)
	191	goto post_context_calculation;
392f6d31	192	i2++;
540d3eb0	193	}
6d5badb2 RS	194
	195	/*
	196	* Otherwise get more context from the
	197	* pre-image.
	198	*/
	199	i1 = xe->xdf1.nrec - 1;
	200	}
	201
	202	fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
14937c2c RS	203	if (fs1 < 0)
	204	fs1 = 0;
	205	if (fs1 < s1) {
	206	s2 -= s1 - fs1;
	207	s1 = fs1;
	208	}
	209	}
	210
6d5badb2	211	post_context_calculation:
3443546f LT	212	lctx = xecfg->ctxlen;
	213	lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
	214	lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
	215
	216	e1 = xche->i1 + xche->chg1 + lctx;
	217	e2 = xche->i2 + xche->chg2 + lctx;
	218
14937c2c RS	219	if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
	220	long fe1 = get_func_line(xe, xecfg, NULL,
	221	xche->i1 + xche->chg1,
	222	xe->xdf1.nrec);
9e6a4cfc RS	223	while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
9e6a4cfc RS	224	fe1--;
14937c2c RS	225	if (fe1 < 0)
	226	fe1 = xe->xdf1.nrec;
	227	if (fe1 > e1) {
	228	e2 += fe1 - e1;
	229	e1 = fe1;
	230	}
	231
	232	/*
	233	* Overlap with next change? Then include it
	234	* in the current hunk and start over to find
	235	* its new end.
	236	*/
	237	if (xche->next) {
6f8d9bcc RS	238	long l = XDL_MIN(xche->next->i1,
6f8d9bcc RS	239	xe->xdf1.nrec - 1);
45d2f75f	240	if (l - xecfg->ctxlen <= e1 \|\|
14937c2c RS	241	get_func_line(xe, xecfg, NULL, l, e1) < 0) {
14937c2c RS	242	xche = xche->next;
6d5badb2	243	goto post_context_calculation;
14937c2c RS	244	}
	245	}
	246	}
	247
3443546f LT	248	/*
	249	* Emit current hunk header.
	250	*/
acb72577 MW	251
acb72577 MW	252	if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
f99f4b36 RS	253	get_func_line(xe, xecfg, &func_line,
f99f4b36 RS	254	s1 - 1, funclineprev);
c099789b	255	funclineprev = s1 - 1;
acb72577 MW	256	}
acb72577 MW	257	if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
f99f4b36	258	func_line.buf, func_line.len, ecb) < 0)
3443546f LT	259	return -1;
	260
	261	/*
	262	* Emit pre-context.
	263	*/
baf5aaa3 RS	264	for (; s2 < xch->i2; s2++)
baf5aaa3 RS	265	if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
3443546f LT	266	return -1;
	267
	268	for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
	269	/*
	270	* Merge previous with current change atom.
	271	*/
	272	for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
baf5aaa3	273	if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
3443546f LT	274	return -1;
	275
	276	/*
	277	* Removes lines from the first file.
	278	*/
	279	for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
	280	if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
	281	return -1;
	282
	283	/*
	284	* Adds lines from the second file.
	285	*/
	286	for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
	287	if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
	288	return -1;
	289
	290	if (xch == xche)
	291	break;
	292	s1 = xch->i1 + xch->chg1;
	293	s2 = xch->i2 + xch->chg2;
	294	}
	295
	296	/*
	297	* Emit post-context.
	298	*/
baf5aaa3 RS	299	for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
baf5aaa3 RS	300	if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
3443546f LT	301	return -1;
	302	}
	303
	304	return 0;
	305	}