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Date:: Wed Apr 20 14:00:12 2022 UTC
Message:: inline struct got_object_id in struct got_object_qid Saves us from doing a malloc/free call for every item on the list. ok op@
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1 /*	$OpenBSD: diff3.c,v 1.41 2016/10/18 21:06:52 millert Exp $	*/
2 
3 /*
4  * Copyright (C) Caldera International Inc.  2001-2002.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code and documentation must retain the above
11  *    copyright notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed or owned by Caldera
18  *	International, Inc.
19  * 4. Neither the name of Caldera International, Inc. nor the names of other
20  *    contributors may be used to endorse or promote products derived from
21  *    this software without specific prior written permission.
22  *
23  * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
24  * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE FOR ANY DIRECT,
28  * INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
30  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
32  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
33  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*-
37  * Copyright (c) 1991, 1993
38  *	The Regents of the University of California.  All rights reserved.
39  *
40  * Redistribution and use in source and binary forms, with or without
41  * modification, are permitted provided that the following conditions
42  * are met:
43  * 1. Redistributions of source code must retain the above copyright
44  *    notice, this list of conditions and the following disclaimer.
45  * 2. Redistributions in binary form must reproduce the above copyright
46  *    notice, this list of conditions and the following disclaimer in the
47  *    documentation and/or other materials provided with the distribution.
48  * 3. Neither the name of the University nor the names of its contributors
49  *    may be used to endorse or promote products derived from this software
50  *    without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62  * SUCH DAMAGE.
63  *
64  *	@(#)diff3.c	8.1 (Berkeley) 6/6/93
65  */
66 
67 #include <sys/stat.h>
68 #include <sys/queue.h>
69 
70 #include <ctype.h>
71 #include <limits.h>
72 #include <sha1.h>
73 #include <stdio.h>
74 #include <stdarg.h>
75 #include <stdlib.h>
76 #include <string.h>
77 #include <time.h>
78 #include <unistd.h>
79 
80 #include "got_error.h"
81 #include "got_opentemp.h"
82 #include "got_object.h"
83 
84 #include "buf.h"
85 #include "rcsutil.h"
86 #include "got_lib_diff.h"
87 
88 #ifndef nitems
89 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
90 #endif
91 
92 /* diff3 - 3-way differential file comparison */
93 
94 /* diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
95  *
96  * d13 = diff report on f1 vs f3
97  * d23 = diff report on f2 vs f3
98  * f1, f2, f3 the 3 files
99  * if changes in f1 overlap with changes in f3, m1 and m3 are used
100  * to mark the overlaps; otherwise, the file names f1 and f3 are used
101  * (only for options E and X).
102  */
103 
104 /*
105  * "from" is first in range of changed lines; "to" is last+1
106  * from=to=line after point of insertion for added lines.
107  */
108 struct line_range {
109 	int from;
110 	int to;
111 };
112 
113 struct off_range {
114 	off_t from;
115 	off_t to;
116 };
117 
118 struct diff {
119 	struct line_range old;
120 	struct line_range new;
121 	struct off_range oldo;
122 	struct off_range newo;
123 };
124 
125 struct diff3_state {
126 	size_t szchanges;
127 
128 	struct diff *d13;
129 	struct diff *d23;
130 
131 	/*
132 	 * "de" is used to gather editing scripts.  These are later spewed out
133 	 * in reverse order.  Its first element must be all zero, the "new"
134 	 * component of "de" contains line positions, and "oldo" and "newo"
135 	 * components contain byte positions.
136 	 * Array overlap indicates which sections in "de" correspond to lines
137 	 * that are different in all three files.
138 	 */
139 	struct diff *de;
140 	char *overlap;
141 	int overlapcnt;
142 	FILE *fp[3];
143 	int cline[3];		/* # of the last-read line in each file (0-2) */
144 
145 	/*
146 	 * the latest known correspondence between line numbers of the 3 files
147 	 * is stored in last[1-3];
148 	 */
149 	int last[4];
150 	char f1mark[PATH_MAX];
151 	char f2mark[PATH_MAX];
152 	char f3mark[PATH_MAX];
153 
154 	char *buf;
155 
156 	BUF *diffbuf;
157 };
158 
159 
160 static const struct got_error *duplicate(int *, int, struct line_range *,
161     struct line_range *, struct diff3_state *);
162 static const struct got_error *edit(struct diff *, int, int *,
163     struct diff3_state *);
164 static const struct got_error *getchange(char **, FILE *, struct diff3_state *);
165 static const struct got_error *get_line(char **, FILE *, size_t *,
166     struct diff3_state *);
167 static int number(char **);
168 static const struct got_error *readin(size_t *, char *, struct diff **,
169     struct diff3_state *);
170 static int ed_patch_lines(struct rcs_lines *, struct rcs_lines *);
171 static const struct got_error *skip(size_t *, int, int, struct diff3_state *);
172 static const struct got_error *edscript(int, struct diff3_state *);
173 static const struct got_error *merge(size_t, size_t, struct diff3_state *);
174 static const struct got_error *prange(struct line_range *,
175     struct diff3_state *);
176 static const struct got_error *repos(int, struct diff3_state *);
177 static const struct got_error *increase(struct diff3_state *);
178 static const struct got_error *diff3_internal(char *, char *, char *,
179     char *, char *, const char *, const char *, struct diff3_state *,
180     const char *, const char *, const char *);
181 
182 static const struct got_error *
183 diff_output(BUF *diffbuf, const char *fmt, ...)
184 {
185 	const struct got_error *err = NULL;
186 	va_list vap;
187 	int i;
188 	char *str;
189 	size_t newsize;
190 
191 	va_start(vap, fmt);
192 	i = vasprintf(&str, fmt, vap);
193 	va_end(vap);
194 	if (i == -1)
195 		return got_error_from_errno("vasprintf");
196 	err = buf_append(&newsize, diffbuf, str, strlen(str));
197 	free(str);
198 	return err;
199 }
200 
201 static const struct got_error*
202 diffreg(BUF **d, const char *path1, const char *path2,
203     enum got_diff_algorithm diff_algo)
204 {
205 	const struct got_error *err = NULL;
206 	FILE *f1 = NULL, *f2 = NULL, *outfile = NULL;
207 	char *outpath = NULL;
208 	struct got_diffreg_result *diffreg_result = NULL;
209 
210 	*d = NULL;
211 
212 	f1 = fopen(path1, "re");
213 	if (f1 == NULL) {
214 		err = got_error_from_errno2("fopen", path1);
215 		goto done;
216 	}
217 	f2 = fopen(path2, "re");
218 	if (f1 == NULL) {
219 		err = got_error_from_errno2("fopen", path2);
220 		goto done;
221 	}
222 
223 	err = got_opentemp_named(&outpath, &outfile,
224 	    GOT_TMPDIR_STR "/got-diffreg");
225 	if (err)
226 		goto done;
227 
228 	err = got_diffreg(&diffreg_result, f1, f2, diff_algo, 0, 0);
229 	if (err)
230 		goto done;
231 
232 	if (diffreg_result) {
233 		struct diff_result *diff_result = diffreg_result->result;
234 		int atomizer_flags = (diff_result->left->atomizer_flags |
235 		    diff_result->right->atomizer_flags);
236 		if ((atomizer_flags & DIFF_ATOMIZER_FOUND_BINARY_DATA)) {
237 			err = got_error(GOT_ERR_FILE_BINARY);
238 			goto done;
239 		}
240 	}
241 
242 	err = got_diffreg_output(NULL, NULL, diffreg_result, 1, 1, "", "",
243 	    GOT_DIFF_OUTPUT_EDSCRIPT, 0, outfile);
244 	if (err)
245 		goto done;
246 
247 	if (fflush(outfile) != 0) {
248 		err = got_error_from_errno2("fflush", outpath);
249 		goto done;
250 	}
251 	if (fseek(outfile, 0L, SEEK_SET) == -1) {
252 		err = got_ferror(outfile, GOT_ERR_IO);
253 		goto done;
254 	}
255 
256 	err = buf_load(d, outfile);
257 done:
258 	if (outpath) {
259 		if (unlink(outpath) == -1 && err == NULL)
260 			err = got_error_from_errno2("unlink", outpath);
261 		free(outpath);
262 	}
263 	if (outfile && fclose(outfile) == EOF && err == NULL)
264 		err = got_error_from_errno("fclose");
265 	if (f1 && fclose(f1) == EOF && err == NULL)
266 		err = got_error_from_errno("fclose");
267 	if (f2 && fclose(f2) == EOF && err == NULL)
268 		err = got_error_from_errno("fclose");
269 	return err;
270 }
271 
272 /*
273  * For merge(1).
274  */
275 const struct got_error *
276 got_merge_diff3(int *overlapcnt, int outfd, FILE *f1, FILE *f2,
277     FILE *f3, const char *label1, const char *label2, const char *label3,
278     enum got_diff_algorithm diff_algo)
279 {
280 	const struct got_error *err = NULL;
281 	char *dp13, *dp23, *path1, *path2, *path3;
282 	BUF *b1, *b2, *b3, *d1, *d2, *diffb;
283 	u_char *data, *patch;
284 	size_t dlen, plen, i;
285 	struct diff3_state *d3s;
286 
287 	*overlapcnt = 0;
288 
289 	d3s = calloc(1, sizeof(*d3s));
290 	if (d3s == NULL)
291 		return got_error_from_errno("calloc");
292 
293 	b1 = b2 = b3 = d1 = d2 = diffb = NULL;
294 	dp13 = dp23 = path1 = path2 = path3 = NULL;
295 	data = patch = NULL;
296 
297 	err = buf_load(&b1, f1);
298 	if (err)
299 		goto out;
300 	err = buf_load(&b2, f2);
301 	if (err)
302 		goto out;
303 	err = buf_load(&b3, f3);
304 	if (err)
305 		goto out;
306 
307 	err = buf_alloc(&diffb, 128);
308 	if (err)
309 		goto out;
310 
311 	if (asprintf(&path1, GOT_TMPDIR_STR "/got-diff1.XXXXXXXX") == -1) {
312 		err = got_error_from_errno("asprintf");
313 		goto out;
314 	}
315 	if (asprintf(&path2, GOT_TMPDIR_STR "/got-diff2.XXXXXXXX") == -1) {
316 		err = got_error_from_errno("asprintf");
317 		goto out;
318 	}
319 	if (asprintf(&path3, GOT_TMPDIR_STR "/got-diff3.XXXXXXXX") == -1) {
320 		err = got_error_from_errno("asprintf");
321 		goto out;
322 	}
323 
324 	err = buf_write_stmp(b1, path1);
325 	if (err)
326 		goto out;
327 	err = buf_write_stmp(b2, path2);
328 	if (err)
329 		goto out;
330 	err = buf_write_stmp(b3, path3);
331 	if (err)
332 		goto out;
333 
334 	buf_free(b2);
335 	b2 = NULL;
336 
337 	err = diffreg(&d1, path1, path3, diff_algo);
338 	if (err) {
339 		buf_free(diffb);
340 		diffb = NULL;
341 		goto out;
342 
343 	}
344 	err = diffreg(&d2, path2, path3, diff_algo);
345 	if (err) {
346 		buf_free(diffb);
347 		diffb = NULL;
348 		goto out;
349 	}
350 
351 	if (asprintf(&dp13, GOT_TMPDIR_STR "/got-d13.XXXXXXXXXX") == -1) {
352 		err = got_error_from_errno("asprintf");
353 		goto out;
354 	}
355 	err = buf_write_stmp(d1, dp13);
356 	if (err)
357 		goto out;
358 
359 	buf_free(d1);
360 	d1 = NULL;
361 
362 	if (asprintf(&dp23, GOT_TMPDIR_STR "/got-d23.XXXXXXXXXX") == -1) {
363 		err = got_error_from_errno("asprintf");
364 		goto out;
365 	}
366 	err = buf_write_stmp(d2, dp23);
367 	if (err)
368 		goto out;
369 
370 	buf_free(d2);
371 	d2 = NULL;
372 
373 	d3s->diffbuf = diffb;
374 	err = diff3_internal(dp13, dp23, path1, path2, path3,
375 	    label1, label3, d3s, label1, label2, label3);
376 	if (err) {
377 		buf_free(diffb);
378 		diffb = NULL;
379 		goto out;
380 	}
381 
382 	plen = buf_len(diffb);
383 	patch = buf_release(diffb);
384 	dlen = buf_len(b1);
385 	data = buf_release(b1);
386 
387 	diffb = rcs_patchfile(data, dlen, patch, plen, ed_patch_lines);
388 out:
389 	buf_free(b2);
390 	buf_free(b3);
391 	buf_free(d1);
392 	buf_free(d2);
393 
394 	if (unlink(path1) == -1 && err == NULL)
395 		err = got_error_from_errno2("unlink", path1);
396 	if (unlink(path2) == -1 && err == NULL)
397 		err = got_error_from_errno2("unlink", path2);
398 	if (unlink(path3) == -1 && err == NULL)
399 		err = got_error_from_errno2("unlink", path3);
400 	if (unlink(dp13) == -1 && err == NULL)
401 		err = got_error_from_errno2("unlink", dp13);
402 	if (unlink(dp23) == -1 && err == NULL)
403 		err = got_error_from_errno2("unlink", dp23);
404 
405 	free(path1);
406 	free(path2);
407 	free(path3);
408 	free(dp13);
409 	free(dp23);
410 	free(data);
411 	free(patch);
412 
413 	for (i = 0; i < nitems(d3s->fp); i++) {
414 		if (d3s->fp[i] && fclose(d3s->fp[i]) == EOF && err == NULL)
415 			err = got_error_from_errno("fclose");
416 	}
417 	if (err == NULL && diffb) {
418 		if (buf_write_fd(diffb, outfd) < 0)
419 			err = got_error_from_errno("buf_write_fd");
420 		*overlapcnt = d3s->overlapcnt;
421 	}
422 	free(d3s);
423 	buf_free(diffb);
424 	return err;
425 }
426 
427 static const struct got_error *
428 diff3_internal(char *dp13, char *dp23, char *path1, char *path2, char *path3,
429     const char *fmark, const char *rmark, struct diff3_state *d3s,
430     const char *label1, const char *label2, const char *label3)
431 {
432 	const struct got_error *err = NULL;
433 	ssize_t m, n;
434 	int i;
435 
436 	i = snprintf(d3s->f1mark, sizeof(d3s->f1mark),
437 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_BEGIN,
438 	    label1 ? " " : "", label1 ? label1 : "");
439 	if (i < 0 || i >= (int)sizeof(d3s->f1mark))
440 		return got_error(GOT_ERR_NO_SPACE);
441 
442 	i = snprintf(d3s->f2mark, sizeof(d3s->f2mark),
443 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_ORIG,
444 	    label2 ? " " : "", label2 ? label2 : "");
445 	if (i < 0 || i >= (int)sizeof(d3s->f2mark))
446 		return got_error(GOT_ERR_NO_SPACE);
447 
448 	i = snprintf(d3s->f3mark, sizeof(d3s->f3mark),
449 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_END,
450 	    label3 ? " " : "", label3 ? label3 : "");
451 	if (i < 0 || i >= (int)sizeof(d3s->f3mark))
452 		return got_error(GOT_ERR_NO_SPACE);
453 
454 	err = increase(d3s);
455 	if (err)
456 		return err;
457 
458 	err = readin(&m, dp13, &d3s->d13, d3s);
459 	if (err)
460 		return err;
461 	err = readin(&n, dp23, &d3s->d23, d3s);
462 	if (err)
463 		return err;
464 
465 	if ((d3s->fp[0] = fopen(path1, "re")) == NULL)
466 		return got_error_from_errno2("fopen", path1);
467 	if ((d3s->fp[1] = fopen(path2, "re")) == NULL)
468 		return got_error_from_errno2("fopen", path2);
469 	if ((d3s->fp[2] = fopen(path3, "re")) == NULL)
470 		return got_error_from_errno2("fopen", path3);
471 
472 	return merge(m, n, d3s);
473 }
474 
475 static int
476 ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines)
477 {
478 	char op, *ep;
479 	struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after;
480 	int start, end, i, lineno;
481 	u_char tmp;
482 
483 	dlp = TAILQ_FIRST(&(dlines->l_lines));
484 	lp = TAILQ_FIRST(&(plines->l_lines));
485 
486 	end = 0;
487 	for (lp = TAILQ_NEXT(lp, l_list); lp != NULL;
488 	    lp = TAILQ_NEXT(lp, l_list)) {
489 		/* Skip blank lines */
490 		if (lp->l_len < 2)
491 			continue;
492 
493 		/* NUL-terminate line buffer for strtol() safety. */
494 		tmp = lp->l_line[lp->l_len - 1];
495 		lp->l_line[lp->l_len - 1] = '\0';
496 
497 		/* len - 1 is NUL terminator so we use len - 2 for 'op' */
498 		op = lp->l_line[lp->l_len - 2];
499 		start = (int)strtol(lp->l_line, &ep, 10);
500 
501 		/* Restore the last byte of the buffer */
502 		lp->l_line[lp->l_len - 1] = tmp;
503 
504 		if (op == 'a') {
505 			if (start > dlines->l_nblines ||
506 			    start < 0 || *ep != 'a')
507 				return -1;
508 		} else if (op == 'c') {
509 			if (start > dlines->l_nblines ||
510 			    start < 0 || (*ep != ',' && *ep != 'c'))
511 				return -1;
512 
513 			if (*ep == ',') {
514 				ep++;
515 				end = (int)strtol(ep, &ep, 10);
516 				if (end < 0 || *ep != 'c')
517 					return -1;
518 			} else {
519 				end = start;
520 			}
521 		}
522 
523 
524 		for (;;) {
525 			if (dlp == NULL)
526 				break;
527 			if (dlp->l_lineno == start)
528 				break;
529 			if (dlp->l_lineno > start) {
530 				dlp = TAILQ_PREV(dlp, tqh, l_list);
531 			} else if (dlp->l_lineno < start) {
532 				ndlp = TAILQ_NEXT(dlp, l_list);
533 				if (ndlp->l_lineno > start)
534 					break;
535 				dlp = ndlp;
536 			}
537 		}
538 
539 		if (dlp == NULL)
540 			return -1;
541 
542 
543 		if (op == 'c') {
544 			insert_after = TAILQ_PREV(dlp, tqh, l_list);
545 			for (i = 0; i <= (end - start); i++) {
546 				ndlp = TAILQ_NEXT(dlp, l_list);
547 				TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list);
548 				dlp = ndlp;
549 			}
550 			dlp = insert_after;
551 		}
552 
553 		if (op == 'a' || op == 'c') {
554 			for (;;) {
555 				ndlp = lp;
556 				lp = TAILQ_NEXT(lp, l_list);
557 				if (lp == NULL)
558 					return -1;
559 
560 				if (lp->l_len == 2 &&
561 				    lp->l_line[0] == '.' &&
562 				    lp->l_line[1] == '\n')
563 					break;
564 
565 				if (lp->l_line[0] == ':') {
566 					lp->l_line++;
567 					lp->l_len--;
568 				}
569 				TAILQ_REMOVE(&(plines->l_lines), lp, l_list);
570 				TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp,
571 				    lp, l_list);
572 				dlp = lp;
573 
574 				lp->l_lineno = start;
575 				lp = ndlp;
576 			}
577 		}
578 
579 		/*
580 		 * always resort lines as the markers might be put at the
581 		 * same line as we first started editing.
582 		 */
583 		lineno = 0;
584 		TAILQ_FOREACH(sort, &(dlines->l_lines), l_list)
585 			sort->l_lineno = lineno++;
586 		dlines->l_nblines = lineno - 1;
587 	}
588 
589 	return (0);
590 }
591 
592 /*
593  * Pick up the line numbers of all changes from one change file.
594  * (This puts the numbers in a vector, which is not strictly necessary,
595  * since the vector is processed in one sequential pass.
596  * The vector could be optimized out of existence)
597  */
598 static const struct got_error *
599 readin(size_t *n, char *name, struct diff **dd, struct diff3_state *d3s)
600 {
601 	const struct got_error *err = NULL;
602 	FILE *f;
603 	int a, b, c, d;
604 	char kind, *p;
605 	size_t i = 0;
606 
607 	*n = 0;
608 
609 	f = fopen(name, "re");
610 	if (f == NULL)
611 		return got_error_from_errno2("fopen", name);
612 	err = getchange(&p, f, d3s);
613 	if (err)
614 		goto done;
615 	for (i = 0; p; i++) {
616 		if (i >= d3s->szchanges - 1) {
617 			err = increase(d3s);
618 			if (err)
619 				goto done;
620 		}
621 		a = b = number(&p);
622 		if (*p == ',') {
623 			p++;
624 			b = number(&p);
625 		}
626 		kind = *p++;
627 		c = d = number(&p);
628 		if (*p == ',') {
629 			p++;
630 			d = number(&p);
631 		}
632 		if (kind == 'a')
633 			a++;
634 		if (kind == 'd')
635 			c++;
636 		b++;
637 		d++;
638 		(*dd)[i].old.from = a;
639 		(*dd)[i].old.to = b;
640 		(*dd)[i].new.from = c;
641 		(*dd)[i].new.to = d;
642 
643 		err = getchange(&p, f, d3s);
644 		if (err)
645 			goto done;
646 	}
647 
648 	if (i) {
649 		(*dd)[i].old.from = (*dd)[i - 1].old.to;
650 		(*dd)[i].new.from = (*dd)[i - 1].new.to;
651 	}
652 done:
653 	if (fclose(f) == EOF && err == NULL)
654 		err = got_error_from_errno("fclose");
655 	if (err == NULL)
656 		*n = i;
657 	return err;
658 }
659 
660 static int
661 number(char **lc)
662 {
663 	int nn;
664 
665 	nn = 0;
666 	while (isdigit((unsigned char)(**lc)))
667 		nn = nn*10 + *(*lc)++ - '0';
668 
669 	return (nn);
670 }
671 
672 static const struct got_error *
673 getchange(char **line, FILE *b, struct diff3_state *d3s)
674 {
675 	const struct got_error *err = NULL;
676 
677 	*line = NULL;
678 	do {
679 		if (*line && isdigit((unsigned char)(*line)[0]))
680 			return NULL;
681 		err = get_line(line, b, NULL, d3s);
682 		if (err)
683 			return err;
684 	} while (*line);
685 
686 	return NULL;
687 }
688 
689 static const struct got_error *
690 get_line(char **ret, FILE *b, size_t *n, struct diff3_state *d3s)
691 {
692 	const struct got_error *err = NULL;
693 	char *cp = NULL;
694 	size_t size;
695 	ssize_t len;
696 	char *new;
697 
698 	*ret = NULL;
699 	if (n != NULL)
700 		*n = 0;
701 
702 	len = getline(&cp, &size, b);
703 	if (len == -1) {
704 		if (ferror(b))
705 			err = got_error_from_errno("getline");
706 		goto done;
707 	}
708 
709 	if (cp[len - 1] != '\n') {
710 		len++;
711 		if (len + 1 > size) {
712 			new = realloc(cp, len + 1);
713 			if (new == NULL) {
714 				err = got_error_from_errno("realloc");
715 				goto done;
716 			}
717 			cp = new;
718 		}
719 		cp[len - 1] = '\n';
720 		cp[len] = '\0';
721 	}
722 
723 	free(d3s->buf);
724 	*ret = d3s->buf = cp;
725 	cp = NULL;
726 	if (n != NULL)
727 		*n = len;
728 done:
729 	free(cp);
730 	return err;
731 }
732 
733 static const struct got_error *
734 merge(size_t m1, size_t m2, struct diff3_state *d3s)
735 {
736 	const struct got_error *err = NULL;
737 	struct diff *d1, *d2;
738 	int dpl, j, t1, t2;
739 
740 	d1 = d3s->d13;
741 	d2 = d3s->d23;
742 	j = 0;
743 	for (;;) {
744 		t1 = (d1 < d3s->d13 + m1);
745 		t2 = (d2 < d3s->d23 + m2);
746 		if (!t1 && !t2)
747 			break;
748 
749 		/* first file is different from others */
750 		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
751 			/* stuff peculiar to 1st file */
752 			d1++;
753 			continue;
754 		}
755 
756 		/* second file is different from others */
757 		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
758 			d2++;
759 			continue;
760 		}
761 
762 		/*
763 		 * Merge overlapping changes in first file
764 		 * this happens after extension (see below).
765 		 */
766 		if (d1 + 1 < d3s->d13 + m1 && d1->new.to >= d1[1].new.from) {
767 			d1[1].old.from = d1->old.from;
768 			d1[1].new.from = d1->new.from;
769 			d1++;
770 			continue;
771 		}
772 
773 		/* merge overlapping changes in second */
774 		if (d2 + 1 < d3s->d23 + m2 && d2->new.to >= d2[1].new.from) {
775 			d2[1].old.from = d2->old.from;
776 			d2[1].new.from = d2->new.from;
777 			d2++;
778 			continue;
779 		}
780 		/* stuff peculiar to third file or different in all */
781 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
782 			err = duplicate(&dpl, j, &d1->old, &d2->old, d3s);
783 			if (err)
784 				return err;
785 
786 			/*
787 			 * dpl = 0 means all files differ
788 			 * dpl = 1 means files 1 and 2 identical
789 			 */
790 			err = edit(d1, dpl, &j, d3s);
791 			if (err)
792 				return err;
793 			d1++;
794 			d2++;
795 			continue;
796 		}
797 
798 		/*
799 		 * Overlapping changes from file 1 and 2; extend changes
800 		 * appropriately to make them coincide.
801 		 */
802 		if (d1->new.from < d2->new.from) {
803 			d2->old.from -= d2->new.from - d1->new.from;
804 			d2->new.from = d1->new.from;
805 		} else if (d2->new.from < d1->new.from) {
806 			d1->old.from -= d1->new.from - d2->new.from;
807 			d1->new.from = d2->new.from;
808 		}
809 		if (d1->new.to > d2->new.to) {
810 			d2->old.to += d1->new.to - d2->new.to;
811 			d2->new.to = d1->new.to;
812 		} else if (d2->new.to > d1->new.to) {
813 			d1->old.to += d2->new.to - d1->new.to;
814 			d1->new.to = d2->new.to;
815 		}
816 	}
817 
818 	return (edscript(j, d3s));
819 }
820 
821 /*
822  * print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1
823  */
824 static const struct got_error *
825 prange(struct line_range *rold, struct diff3_state *d3s)
826 {
827 	const struct got_error *err = NULL;
828 
829 	if (rold->to <= rold->from) {
830 		err = diff_output(d3s->diffbuf, "%da\n", rold->from - 1);
831 		if (err)
832 			return err;
833 	} else {
834 		err = diff_output(d3s->diffbuf, "%d", rold->from);
835 		if (err)
836 			return err;
837 		if (rold->to > rold->from + 1) {
838 			err = diff_output(d3s->diffbuf, ",%d", rold->to - 1);
839 			if (err)
840 				return err;
841 		}
842 		err = diff_output(d3s->diffbuf, "c\n");
843 		if (err)
844 			return err;
845 	}
846 
847 	return NULL;
848 }
849 
850 /*
851  * Skip to just before line number from in file "i".
852  * Return the number of bytes skipped in *nskipped.
853  */
854 static const struct got_error *
855 skip(size_t *nskipped, int i, int from, struct diff3_state *d3s)
856 {
857 	const struct got_error *err = NULL;
858 	size_t len, n;
859 	char *line;
860 
861 	*nskipped = 0;
862 	for (n = 0; d3s->cline[i] < from - 1; n += len) {
863 		err = get_line(&line, d3s->fp[i], &len, d3s);
864 		if (err)
865 			return err;
866 		d3s->cline[i]++;
867 	}
868 	*nskipped = n;
869 	return NULL;
870 }
871 
872 /*
873  * Set *dpl to 1 or 0 according as the old range (in file 1) contains exactly
874  * the same data as the new range (in file 2).
875  *
876  * If this change could overlap, remember start/end offsets in file 2 so we
877  * can write out the original lines of text if a merge conflict occurs.
878  */
879 static const struct got_error *
880 duplicate(int *dpl, int j, struct line_range *r1, struct line_range *r2,
881     struct diff3_state *d3s)
882 {
883 	const struct got_error *err = NULL;
884 	int c,d;
885 	int nchar;
886 	int nline;
887 	size_t nskipped;
888 	off_t off;
889 
890 	*dpl = 0;
891 
892 	if (r1->to - r1->from != r2->to - r2->from)
893 		return NULL;
894 
895 	err = skip(&nskipped, 0, r1->from, d3s);
896 	if (err)
897 		return err;
898 	err = skip(&nskipped, 1, r2->from, d3s);
899 	if (err)
900 		return err;
901 
902 	off = ftello(d3s->fp[1]);
903 	if (off == -1)
904 		return got_error_from_errno("ftello");
905 	d3s->de[j + 1].oldo.from = off; /* original lines start here */
906 
907 	nchar = 0;
908 	for (nline = 0; nline < r1->to - r1->from; nline++) {
909 		do {
910 			c = getc(d3s->fp[0]);
911 			d = getc(d3s->fp[1]);
912 			if (c == EOF && d == EOF)
913 				break;
914 			else if (c == EOF)
915 				return got_ferror(d3s->fp[0], GOT_ERR_EOF);
916 			else if (d == EOF)
917 				return got_ferror(d3s->fp[1], GOT_ERR_EOF);
918 			nchar++;
919 			if (c != d) {
920 				long orig_line_len = nchar;
921 				while (d != '\n') {
922 					d = getc(d3s->fp[1]);
923 					if (d == EOF)
924 						break;
925 					orig_line_len++;
926 				}
927 				if (orig_line_len > nchar &&
928 				    fseek(d3s->fp[1], -(orig_line_len - nchar),
929 				    SEEK_CUR) == -1)
930 					return got_ferror(d3s->fp[1],
931 						GOT_ERR_IO);
932 				/* original lines end here */
933 				d3s->de[j + 1].oldo.to = off + orig_line_len;
934 				err = repos(nchar, d3s);
935 				if (err)
936 					return err;
937 				return NULL;
938 			}
939 		} while (c != '\n');
940 	}
941 
942 	/* original lines end here */
943 	d3s->de[j + 1].oldo.to = off + nchar;
944 
945 	err = repos(nchar, d3s);
946 	if (err)
947 		return err;
948 	*dpl = 1;
949 	return NULL;
950 }
951 
952 static const struct got_error *
953 repos(int nchar, struct diff3_state *d3s)
954 {
955 	int i;
956 
957 	for (i = 0; i < 2; i++) {
958 		if (fseek(d3s->fp[i], (long)-nchar, SEEK_CUR) == -1)
959 			return got_ferror(d3s->fp[i], GOT_ERR_IO);
960 	}
961 
962 	return NULL;
963 }
964 
965 /*
966  * collect an editing script for later regurgitation
967  */
968 static const struct got_error *
969 edit(struct diff *diff, int fdup, int *j, struct diff3_state *d3s)
970 {
971 	const struct got_error *err = NULL;
972 	size_t nskipped;
973 
974 	if (((fdup + 1) & 3) == 0)
975 		return NULL;
976 	(*j)++;
977 	d3s->overlap[*j] = !fdup;
978 	if (!fdup)
979 		d3s->overlapcnt++;
980 	d3s->de[*j].old.from = diff->old.from;
981 	d3s->de[*j].old.to = diff->old.to;
982 
983 	err = skip(&nskipped, 2, diff->new.from, d3s);
984 	if (err)
985 		return err;
986 	d3s->de[*j].newo.from = d3s->de[*j - 1].newo.to + nskipped;
987 
988 	err = skip(&nskipped, 2, diff->new.to, d3s);
989 	if (err)
990 		return err;
991 	d3s->de[*j].newo.to = d3s->de[*j].newo.from + nskipped;
992 	return NULL;
993 }
994 
995 /* regurgitate */
996 static const struct got_error *
997 edscript(int n, struct diff3_state *d3s)
998 {
999 	const struct got_error *err = NULL;
1000 	off_t len;
1001 	char *line = NULL;
1002 	size_t linesize = 0;
1003 	ssize_t linelen = 0, k;
1004 
1005 	for (; n > 0; n--) {
1006 		if (!d3s->overlap[n]) {
1007 			err = prange(&d3s->de[n].old, d3s);
1008 			if (err)
1009 				return err;
1010 		} else if (d3s->de[n].oldo.from < d3s->de[n].oldo.to) {
1011 			/* Output a block of 3-way diff base file content. */
1012 			err = diff_output(d3s->diffbuf, "%da\n:%s\n",
1013 			    d3s->de[n].old.to - 1, d3s->f2mark);
1014 			if (err)
1015 				return err;
1016 			if (fseeko(d3s->fp[1], d3s->de[n].oldo.from, SEEK_SET)
1017 			    == -1)
1018 				return got_error_from_errno("fseeko");
1019 			len = (d3s->de[n].oldo.to - d3s->de[n].oldo.from);
1020 			for (k = 0; k < (ssize_t)len; k += linelen) {
1021 				linelen = getline(&line, &linesize, d3s->fp[1]);
1022 				if (linelen == -1) {
1023 					if (feof(d3s->fp[1]))
1024 						break;
1025 					err = got_ferror(d3s->fp[1],
1026 					    GOT_ERR_IO);
1027 					goto done;
1028 				}
1029 				err = diff_output(d3s->diffbuf, ":%s", line);
1030 				if (err)
1031 					goto done;
1032 			}
1033 			err = diff_output(d3s->diffbuf, "%s%s\n",
1034 			    linelen > 0 && line[linelen] == '\n' ? ":" : "",
1035 			    GOT_DIFF_CONFLICT_MARKER_SEP);
1036 			if (err)
1037 				goto done;
1038 		} else {
1039 			err = diff_output(d3s->diffbuf, "%da\n:%s\n",
1040 			    d3s->de[n].old.to -1, GOT_DIFF_CONFLICT_MARKER_SEP);
1041 			if (err)
1042 				goto done;
1043 		}
1044 		if (fseeko(d3s->fp[2], d3s->de[n].newo.from, SEEK_SET)
1045 		    == -1) {
1046 			err = got_error_from_errno("fseek");
1047 			goto done;
1048 		}
1049 		len = (d3s->de[n].newo.to - d3s->de[n].newo.from);
1050 		for (k = 0; k < (ssize_t)len; k += linelen) {
1051 			linelen = getline(&line, &linesize, d3s->fp[2]);
1052 			if (linelen == -1) {
1053 				if (feof(d3s->fp[2]))
1054 					break;
1055 				err = got_ferror(d3s->fp[2], GOT_ERR_IO);
1056 				goto done;
1057 			}
1058 			err = diff_output(d3s->diffbuf, ":%s", line);
1059 			if (err)
1060 				goto done;
1061 		}
1062 
1063 		if (!d3s->overlap[n]) {
1064 			err = diff_output(d3s->diffbuf, ".\n");
1065 			if (err)
1066 				goto done;
1067 		} else {
1068 			err = diff_output(d3s->diffbuf, "%s%s\n.\n",
1069 			    linelen > 0 && line[linelen] == '\n' ? ":" : "",
1070 			    d3s->f3mark);
1071 			if (err)
1072 				goto done;
1073 			err = diff_output(d3s->diffbuf, "%da\n:%s\n.\n",
1074 			    d3s->de[n].old.from - 1, d3s->f1mark);
1075 			if (err)
1076 				goto done;
1077 		}
1078 	}
1079 done:
1080 	free(line);
1081 	return err;
1082 }
1083 
1084 static const struct got_error *
1085 increase(struct diff3_state *d3s)
1086 {
1087 	size_t newsz, incr;
1088 	struct diff *d;
1089 	char *s;
1090 
1091 	/* are the memset(3) calls needed? */
1092 	newsz = d3s->szchanges == 0 ? 64 : 2 * d3s->szchanges;
1093 	incr = newsz - d3s->szchanges;
1094 
1095 	d = reallocarray(d3s->d13, newsz, sizeof(*d3s->d13));
1096 	if (d == NULL)
1097 		return got_error_from_errno("reallocarray");
1098 	d3s->d13 = d;
1099 	memset(d3s->d13 + d3s->szchanges, 0, incr * sizeof(*d3s->d13));
1100 
1101 	d = reallocarray(d3s->d23, newsz, sizeof(*d3s->d23));
1102 	if (d == NULL)
1103 		return got_error_from_errno("reallocarray");
1104 	d3s->d23 = d;
1105 	memset(d3s->d23 + d3s->szchanges, 0, incr * sizeof(*d3s->d23));
1106 
1107 	d = reallocarray(d3s->de, newsz, sizeof(*d3s->de));
1108 	if (d == NULL)
1109 		return got_error_from_errno("reallocarray");
1110 	d3s->de = d;
1111 	memset(d3s->de + d3s->szchanges, 0, incr * sizeof(*d3s->de));
1112 
1113 	s = reallocarray(d3s->overlap, newsz, sizeof(*d3s->overlap));
1114 	if (s == NULL)
1115 		return got_error_from_errno("reallocarray");
1116 	d3s->overlap = s;
1117 	memset(d3s->overlap + d3s->szchanges, 0, incr * sizeof(*d3s->overlap));
1118 	d3s->szchanges = newsz;
1119 
1120 	return NULL;
1121 }