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Linus Torvalds34435462006-03-24 20:13:22 -08001/*
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
Todd Zullinger48425792017-11-07 00:39:33 -050016 * License along with this library; if not, see
17 * <http://www.gnu.org/licenses/>.
Linus Torvalds34435462006-03-24 20:13:22 -080018 *
19 * Davide Libenzi <davidel@xmailserver.org>
20 *
21 */
22
23#include "xinclude.h"
24
Linus Torvalds34435462006-03-24 20:13:22 -080025static 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
33static 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.
Antoine Pelisse36617af2013-06-19 20:46:07 +020050 * Also advance xscr if the first changes must be discarded.
Linus Torvalds34435462006-03-24 20:13:22 -080051 */
Antoine Pelisse36617af2013-06-19 20:46:07 +020052xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
53{
54 xdchange_t *xch, *xchp, *lxch;
René Scharfe6d0e6742008-12-28 19:45:32 +010055 long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
Antoine Pelisse36617af2013-06-19 20:46:07 +020056 long max_ignorable = xecfg->ctxlen;
57 unsigned long ignored = 0; /* number of ignored blank lines */
Linus Torvalds34435462006-03-24 20:13:22 -080058
Antoine Pelisse36617af2013-06-19 20:46:07 +020059 /* 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
Junio C Hamanoafe8a902022-05-02 09:50:37 -070068 if (!*xscr)
Antoine Pelisse36617af2013-06-19 20:46:07 +020069 return NULL;
70
71 lxch = *xscr;
72
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)
Linus Torvalds34435462006-03-24 20:13:22 -080076 break;
77
Antoine Pelisse36617af2013-06-19 20:46:07 +020078 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;
Linus Torvalds34435462006-03-24 20:13:22 -080095}
96
97
Jeff Kinga3616602022-12-13 06:13:08 -050098static long def_ff(const char *rec, long len, char *buf, long sz)
Junio C Hamanof2584752007-07-06 00:45:10 -070099{
100 if (len > 0 &&
101 (isalpha((unsigned char)*rec) || /* identifier? */
Junio C Hamanoc01499e2013-10-16 10:26:39 -0700102 *rec == '_' || /* also identifier? */
Junio C Hamanof2584752007-07-06 00:45:10 -0700103 *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
René Scharfeff2981f2016-05-28 16:58:47 +0200114static 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)
Jeff Kinga3616602022-12-13 06:13:08 -0500120 return def_ff(rec, len, buf, sz);
René Scharfeff2981f2016-05-28 16:58:47 +0200121 return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
122}
123
René Scharfecde32bf2017-11-18 19:04:40 +0100124static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
125{
126 char dummy[1];
127 return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
128}
129
René Scharfef99f4b32011-10-09 13:34:49 +0200130struct func_line {
131 long len;
132 char buf[80];
133};
134
René Scharfe14937c22011-10-09 13:36:57 +0200135static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
René Scharfef99f4b32011-10-09 13:34:49 +0200136 struct func_line *func_line, long start, long limit)
137{
René Scharfe14937c22011-10-09 13:36:57 +0200138 long l, size, step = (start > limit) ? -1 : 1;
139 char *buf, dummy[1];
René Scharfef99f4b32011-10-09 13:34:49 +0200140
René Scharfe14937c22011-10-09 13:36:57 +0200141 buf = func_line ? func_line->buf : dummy;
142 size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
143
144 for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
René Scharfeff2981f2016-05-28 16:58:47 +0200145 long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
René Scharfef99f4b32011-10-09 13:34:49 +0200146 if (len >= 0) {
René Scharfe14937c22011-10-09 13:36:57 +0200147 if (func_line)
148 func_line->len = len;
149 return l;
René Scharfef99f4b32011-10-09 13:34:49 +0200150 }
151 }
René Scharfe14937c22011-10-09 13:36:57 +0200152 return -1;
René Scharfef99f4b32011-10-09 13:34:49 +0200153}
154
René Scharfe392f6d32016-05-28 17:02:24 +0200155static int is_empty_rec(xdfile_t *xdf, long ri)
156{
157 const char *rec;
158 long len = xdl_get_rec(xdf, ri, &rec);
159
160 while (len > 0 && XDL_ISSPACE(*rec)) {
161 rec++;
162 len--;
163 }
164 return !len;
165}
166
Linus Torvalds34435462006-03-24 20:13:22 -0800167int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
168 xdemitconf_t const *xecfg) {
169 long s1, s2, e1, e2, lctx;
170 xdchange_t *xch, *xche;
René Scharfec0997892010-09-26 18:26:56 +0200171 long funclineprev = -1;
René Scharfef99f4b32011-10-09 13:34:49 +0200172 struct func_line func_line = { 0 };
Linus Torvalds34435462006-03-24 20:13:22 -0800173
Benjamin Kramer8e24cba2009-03-15 22:01:20 +0100174 for (xch = xscr; xch; xch = xche->next) {
René Scharfe0bb313a2019-12-05 17:15:31 +0100175 xdchange_t *xchp = xch;
Antoine Pelisse36617af2013-06-19 20:46:07 +0200176 xche = xdl_get_hunk(&xch, xecfg);
177 if (!xch)
178 break;
Linus Torvalds34435462006-03-24 20:13:22 -0800179
René Scharfe0bb313a2019-12-05 17:15:31 +0100180pre_context_calculation:
Linus Torvalds34435462006-03-24 20:13:22 -0800181 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
182 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
183
René Scharfe14937c22011-10-09 13:36:57 +0200184 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
René Scharfe6d5badb2016-05-28 17:00:28 +0200185 long fs1, i1 = xch->i1;
186
187 /* Appended chunk? */
188 if (i1 >= xe->xdf1.nrec) {
René Scharfe392f6d32016-05-28 17:02:24 +0200189 long i2 = xch->i2;
René Scharfe6d5badb2016-05-28 17:00:28 +0200190
191 /*
192 * We don't need additional context if
Vegard Nossum540d3eb2017-01-13 17:15:10 +0100193 * a whole function was added.
René Scharfe6d5badb2016-05-28 17:00:28 +0200194 */
Vegard Nossum540d3eb2017-01-13 17:15:10 +0100195 while (i2 < xe->xdf2.nrec) {
René Scharfecde32bf2017-11-18 19:04:40 +0100196 if (is_func_rec(&xe->xdf2, xecfg, i2))
Vegard Nossum540d3eb2017-01-13 17:15:10 +0100197 goto post_context_calculation;
René Scharfe392f6d32016-05-28 17:02:24 +0200198 i2++;
Vegard Nossum540d3eb2017-01-13 17:15:10 +0100199 }
René Scharfe6d5badb2016-05-28 17:00:28 +0200200
201 /*
202 * Otherwise get more context from the
203 * pre-image.
204 */
205 i1 = xe->xdf1.nrec - 1;
206 }
207
208 fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
René Scharfe5c3ed902017-11-18 19:05:19 +0100209 while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
210 !is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
211 fs1--;
René Scharfe14937c22011-10-09 13:36:57 +0200212 if (fs1 < 0)
213 fs1 = 0;
214 if (fs1 < s1) {
Jeff Kingb777f3f2019-07-23 15:27:05 -0400215 s2 = XDL_MAX(s2 - (s1 - fs1), 0);
René Scharfe14937c22011-10-09 13:36:57 +0200216 s1 = fs1;
René Scharfe0bb313a2019-12-05 17:15:31 +0100217
218 /*
219 * Did we extend context upwards into an
220 * ignored change?
221 */
222 while (xchp != xch &&
223 xchp->i1 + xchp->chg1 <= s1 &&
224 xchp->i2 + xchp->chg2 <= s2)
225 xchp = xchp->next;
226
227 /* If so, show it after all. */
228 if (xchp != xch) {
229 xch = xchp;
230 goto pre_context_calculation;
231 }
René Scharfe14937c22011-10-09 13:36:57 +0200232 }
233 }
234
René Scharfe6d5badb2016-05-28 17:00:28 +0200235 post_context_calculation:
Linus Torvalds34435462006-03-24 20:13:22 -0800236 lctx = xecfg->ctxlen;
237 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
238 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
239
240 e1 = xche->i1 + xche->chg1 + lctx;
241 e2 = xche->i2 + xche->chg2 + lctx;
242
René Scharfe14937c22011-10-09 13:36:57 +0200243 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
244 long fe1 = get_func_line(xe, xecfg, NULL,
245 xche->i1 + xche->chg1,
246 xe->xdf1.nrec);
René Scharfe9e6a4cf2016-05-28 17:03:16 +0200247 while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
248 fe1--;
René Scharfe14937c22011-10-09 13:36:57 +0200249 if (fe1 < 0)
250 fe1 = xe->xdf1.nrec;
251 if (fe1 > e1) {
Jeff Kingb777f3f2019-07-23 15:27:05 -0400252 e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
René Scharfe14937c22011-10-09 13:36:57 +0200253 e1 = fe1;
254 }
255
256 /*
257 * Overlap with next change? Then include it
258 * in the current hunk and start over to find
259 * its new end.
260 */
261 if (xche->next) {
René Scharfe6f8d9bc2016-06-09 23:54:48 +0200262 long l = XDL_MIN(xche->next->i1,
263 xe->xdf1.nrec - 1);
René Scharfe45d2f752016-09-14 18:05:27 +0200264 if (l - xecfg->ctxlen <= e1 ||
René Scharfe14937c22011-10-09 13:36:57 +0200265 get_func_line(xe, xecfg, NULL, l, e1) < 0) {
266 xche = xche->next;
René Scharfe6d5badb2016-05-28 17:00:28 +0200267 goto post_context_calculation;
René Scharfe14937c22011-10-09 13:36:57 +0200268 }
269 }
270 }
271
Linus Torvalds34435462006-03-24 20:13:22 -0800272 /*
273 * Emit current hunk header.
274 */
Mark Woodingacb72572006-03-28 03:23:31 +0100275
276 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
René Scharfef99f4b32011-10-09 13:34:49 +0200277 get_func_line(xe, xecfg, &func_line,
278 s1 - 1, funclineprev);
René Scharfec0997892010-09-26 18:26:56 +0200279 funclineprev = s1 - 1;
Mark Woodingacb72572006-03-28 03:23:31 +0100280 }
Ævar Arnfjörð Bjarmason5d934602021-04-12 19:15:29 +0200281 if (!(xecfg->flags & XDL_EMIT_NO_HUNK_HDR) &&
282 xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
René Scharfef99f4b32011-10-09 13:34:49 +0200283 func_line.buf, func_line.len, ecb) < 0)
Linus Torvalds34435462006-03-24 20:13:22 -0800284 return -1;
285
286 /*
287 * Emit pre-context.
288 */
René Scharfebaf5aaa2012-01-06 18:13:00 +0100289 for (; s2 < xch->i2; s2++)
290 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
Linus Torvalds34435462006-03-24 20:13:22 -0800291 return -1;
292
293 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
294 /*
295 * Merge previous with current change atom.
296 */
297 for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
René Scharfebaf5aaa2012-01-06 18:13:00 +0100298 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
Linus Torvalds34435462006-03-24 20:13:22 -0800299 return -1;
300
301 /*
302 * Removes lines from the first file.
303 */
304 for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
305 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
306 return -1;
307
308 /*
309 * Adds lines from the second file.
310 */
311 for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
312 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
313 return -1;
314
315 if (xch == xche)
316 break;
317 s1 = xch->i1 + xch->chg1;
318 s2 = xch->i2 + xch->chg2;
319 }
320
321 /*
322 * Emit post-context.
323 */
René Scharfebaf5aaa2012-01-06 18:13:00 +0100324 for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
325 if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
Linus Torvalds34435462006-03-24 20:13:22 -0800326 return -1;
327 }
328
329 return 0;
330}