1 /*
2  * Copyright (c) 2017 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/queue.h>
18 #include <sys/stat.h>
19 
20 #include <stdbool.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <limits.h>
25 #include <sha1.h>
26 #include <zlib.h>
27 
28 #include "got_object.h"
29 #include "got_repository.h"
30 #include "got_error.h"
31 #include "got_diff.h"
32 #include "got_opentemp.h"
33 #include "got_path.h"
34 #include "got_cancel.h"
35 #include "got_worktree.h"
36 
37 #include "got_lib_diff.h"
38 #include "got_lib_delta.h"
39 #include "got_lib_inflate.h"
40 #include "got_lib_object.h"
41 
42 static const struct got_error *
43 add_line_offset(off_t **line_offsets, size_t *nlines, off_t off)
44 {
45 	off_t *p;
46 
47 	p = reallocarray(*line_offsets, *nlines + 1, sizeof(off_t));
48 	if (p == NULL)
49 		return got_error_from_errno("reallocarray");
50 	*line_offsets = p;
51 	(*line_offsets)[*nlines] = off;
52 	(*nlines)++;
53 	return NULL;
54 }
55 
56 static const struct got_error *
57 diff_blobs(off_t **line_offsets, size_t *nlines,
58     struct got_diffreg_result **resultp, struct got_blob_object *blob1,
59     struct got_blob_object *blob2,
60     const char *label1, const char *label2, mode_t mode1, mode_t mode2,
61     int diff_context, int ignore_whitespace, FILE *outfile)
62 {
63 	const struct got_error *err = NULL, *free_err;
64 	FILE *f1 = NULL, *f2 = NULL;
65 	char hex1[SHA1_DIGEST_STRING_LENGTH];
66 	char hex2[SHA1_DIGEST_STRING_LENGTH];
67 	char *idstr1 = NULL, *idstr2 = NULL;
68 	size_t size1, size2;
69 	struct got_diffreg_result *result;
70 	off_t outoff = 0;
71 	int n;
72 
73 	if (line_offsets && *line_offsets && *nlines > 0)
74 		outoff = (*line_offsets)[*nlines - 1];
75 
76 	if (resultp)
77 		*resultp = NULL;
78 
79 	if (blob1) {
80 		f1 = got_opentemp();
81 		if (f1 == NULL)
82 			return got_error_from_errno("got_opentemp");
83 	}
84 
85 	if (blob2) {
86 		f2 = got_opentemp();
87 		if (f2 == NULL) {
88 			err = got_error_from_errno("got_opentemp");
89 			fclose(f1);
90 			return err;
91 		}
92 	}
93 
94 	size1 = 0;
95 	if (blob1) {
96 		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
97 		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
98 		    blob1);
99 		if (err)
100 			goto done;
101 	} else
102 		idstr1 = "/dev/null";
103 
104 	size2 = 0;
105 	if (blob2) {
106 		idstr2 = got_object_blob_id_str(blob2, hex2, sizeof(hex2));
107 		err = got_object_blob_dump_to_file(&size2, NULL, NULL, f2,
108 		    blob2);
109 		if (err)
110 			goto done;
111 	} else
112 		idstr2 = "/dev/null";
113 
114 	if (outfile) {
115 		char *modestr1 = NULL, *modestr2 = NULL;
116 		int modebits;
117 		if (mode1 && mode1 != mode2) {
118 			if (S_ISLNK(mode1))
119 				modebits = S_IFLNK;
120 			else
121 				modebits = (S_IRWXU | S_IRWXG | S_IRWXO);
122 			if (asprintf(&modestr1, " (mode %o)",
123 			    mode1 & modebits) == -1) {
124 				err = got_error_from_errno("asprintf");
125 				goto done;
126 			}
127 		}
128 		if (mode2 && mode1 != mode2) {
129 			if (S_ISLNK(mode2))
130 				modebits = S_IFLNK;
131 			else
132 				modebits = (S_IRWXU | S_IRWXG | S_IRWXO);
133 			if (asprintf(&modestr2, " (mode %o)",
134 			    mode2 & modebits) == -1) {
135 				err = got_error_from_errno("asprintf");
136 				goto done;
137 			}
138 		}
139 		n = fprintf(outfile, "blob - %s%s\n", idstr1,
140 		    modestr1 ? modestr1 : "");
141 		if (n < 0)
142 			goto done;
143 		outoff += n;
144 		if (line_offsets) {
145 			err = add_line_offset(line_offsets, nlines, outoff);
146 			if (err)
147 				goto done;
148 		}
149 
150 		n = fprintf(outfile, "blob + %s%s\n", idstr2,
151 		    modestr2 ? modestr2 : "");
152 		if (n < 0)
153 			goto done;
154 		outoff += n;
155 		if (line_offsets) {
156 			err = add_line_offset(line_offsets, nlines, outoff);
157 			if (err)
158 				goto done;
159 		}
160 
161 		free(modestr1);
162 		free(modestr2);
163 	}
164 	err = got_diffreg(&result, f1, f2, GOT_DIFF_ALGORITHM_PATIENCE,
165 	    ignore_whitespace);
166 	if (err)
167 		goto done;
168 
169 	if (outfile) {
170 		err = got_diffreg_output(line_offsets, nlines, result, f1, f2,
171 		    label1 ? label1 : idstr1,
172 		    label2 ? label2 : idstr2,
173 		    GOT_DIFF_OUTPUT_UNIDIFF, diff_context, outfile);
174 		if (err)
175 			goto done;
176 	}
177 
178 	if (resultp && err == NULL)
179 		*resultp = result;
180 	else {
181 		free_err = got_diffreg_result_free(result);
182 		if (free_err && err == NULL)
183 			err = free_err;
184 	}
185 done:
186 	if (f1 && fclose(f1) != 0 && err == NULL)
187 		err = got_error_from_errno("fclose");
188 	if (f2 && fclose(f2) != 0 && err == NULL)
189 		err = got_error_from_errno("fclose");
190 	return err;
191 }
192 
193 const struct got_error *
194 got_diff_blob_output_unidiff(void *arg, struct got_blob_object *blob1,
195     struct got_blob_object *blob2, struct got_object_id *id1,
196     struct got_object_id *id2, const char *label1, const char *label2,
197     mode_t mode1, mode_t mode2, struct got_repository *repo)
198 {
199 	struct got_diff_blob_output_unidiff_arg *a = arg;
200 
201 	return diff_blobs(&a->line_offsets, &a->nlines, NULL,
202 	    blob1, blob2, label1, label2, mode1, mode2, a->diff_context,
203 	    a->ignore_whitespace, a->outfile);
204 }
205 
206 const struct got_error *
207 got_diff_blob(off_t **line_offsets, size_t *nlines,
208     struct got_blob_object *blob1, struct got_blob_object *blob2,
209     const char *label1, const char *label2, int diff_context,
210     int ignore_whitespace, FILE *outfile)
211 {
212 	return diff_blobs(line_offsets, nlines, NULL, blob1, blob2,
213 	    label1, label2, 0, 0, diff_context, ignore_whitespace, outfile);
214 }
215 
216 static const struct got_error *
217 diff_blob_file(struct got_diffreg_result **resultp,
218     struct got_blob_object *blob1, const char *label1, FILE *f2, size_t size2,
219     const char *label2, int diff_context, int ignore_whitespace, FILE *outfile)
220 {
221 	const struct got_error *err = NULL, *free_err;
222 	FILE *f1 = NULL;
223 	char hex1[SHA1_DIGEST_STRING_LENGTH];
224 	char *idstr1 = NULL;
225 	size_t size1;
226 	struct got_diffreg_result *result = NULL;
227 
228 	if (resultp)
229 		*resultp = NULL;
230 
231 	size1 = 0;
232 	if (blob1) {
233 		f1 = got_opentemp();
234 		if (f1 == NULL)
235 			return got_error_from_errno("got_opentemp");
236 		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
237 		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
238 		    blob1);
239 		if (err)
240 			goto done;
241 	} else {
242 		idstr1 = "/dev/null";
243 	}
244 
245 	if (outfile) {
246 		fprintf(outfile, "blob - %s\n", label1 ? label1 : idstr1);
247 		fprintf(outfile, "file + %s\n",
248 		    f2 == NULL ? "/dev/null" : label2);
249 	}
250 
251 	err = got_diffreg(&result, f1, f2, GOT_DIFF_ALGORITHM_PATIENCE, 
252 	    ignore_whitespace);
253 	if (err)
254 		goto done;
255 
256 	if (outfile) {
257 		err = got_diffreg_output(NULL, NULL, result, f1, f2,
258 		    label2, label2, GOT_DIFF_OUTPUT_UNIDIFF, diff_context,
259 		    outfile);
260 		if (err)
261 			goto done;
262 	}
263 
264 	if (resultp && err == NULL)
265 		*resultp = result;
266 	else if (result) {
267 		free_err = got_diffreg_result_free(result);
268 		if (free_err && err == NULL)
269 			err = free_err;
270 	}
271 done:
272 	if (f1 && fclose(f1) != 0 && err == NULL)
273 		err = got_error_from_errno("fclose");
274 	return err;
275 }
276 
277 const struct got_error *
278 got_diff_blob_file(struct got_blob_object *blob1, const char *label1,
279     FILE *f2, size_t size2, const char *label2, int diff_context,
280     int ignore_whitespace, FILE *outfile)
281 {
282 	return diff_blob_file(NULL, blob1, label1, f2, size2, label2,
283 	    diff_context, ignore_whitespace, outfile);
284 }
285 
286 const struct got_error *
287 got_diff_blob_prepared_file(struct got_diffreg_result **resultp,
288     struct diff_data *data1, struct got_blob_object *blob1,
289     struct diff_data *data2, FILE *f2, char *p2, size_t size2,
290     const struct diff_config *cfg, int ignore_whitespace)
291 {
292 	const struct got_error *err = NULL, *free_err;
293 	FILE *f1 = NULL;
294 	char hex1[SHA1_DIGEST_STRING_LENGTH];
295 	char *idstr1 = NULL, *p1 = NULL;
296 	size_t size1, size;
297 	struct got_diffreg_result *result = NULL;
298 	int f1_created = 0;
299 
300 	*resultp = NULL;
301 
302 	size1 = 0;
303 	if (blob1) {
304 		f1 = got_opentemp();
305 		if (f1 == NULL)
306 			return got_error_from_errno("got_opentemp");
307 		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
308 		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
309 		    blob1);
310 		if (err)
311 			goto done;
312 	} else {
313 		idstr1 = "/dev/null";
314 	}
315 
316 	err = got_diff_prepare_file(&f1, &p1, &f1_created, &size,
317 	    data1, cfg, ignore_whitespace);
318 	if (err)
319 		goto done;
320 
321 	err = got_diffreg_prepared_files(&result, cfg, data1, f1,
322 	    p1, size1, data2, f2, p2, size2);
323 	if (err)
324 		goto done;
325 
326 	*resultp = result;
327 done:
328 	if (err) {
329 		if (result)
330 			free_err = got_diffreg_result_free_left(result);
331 		else
332 			free_err = got_diffreg_close(f1, p1, size1, NULL,
333 			    NULL, 0);
334 		if (free_err && err == NULL)
335 			err = free_err;
336 	}
337 	return err;
338 }
339 
340 static const struct got_error *
341 diff_added_blob(struct got_object_id *id, const char *label, mode_t mode,
342     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
343 {
344 	const struct got_error *err;
345 	struct got_blob_object  *blob = NULL;
346 	struct got_object *obj = NULL;
347 
348 	err = got_object_open(&obj, repo, id);
349 	if (err)
350 		return err;
351 
352 	err = got_object_blob_open(&blob, repo, obj, 8192);
353 	if (err)
354 		goto done;
355 	err = cb(cb_arg, NULL, blob, NULL, id, NULL, label, 0, mode, repo);
356 done:
357 	got_object_close(obj);
358 	if (blob)
359 		got_object_blob_close(blob);
360 	return err;
361 }
362 
363 static const struct got_error *
364 diff_modified_blob(struct got_object_id *id1, struct got_object_id *id2,
365     const char *label1, const char *label2, mode_t mode1, mode_t mode2,
366     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
367 {
368 	const struct got_error *err;
369 	struct got_object *obj1 = NULL;
370 	struct got_object *obj2 = NULL;
371 	struct got_blob_object *blob1 = NULL;
372 	struct got_blob_object *blob2 = NULL;
373 
374 	err = got_object_open(&obj1, repo, id1);
375 	if (err)
376 		return err;
377 	if (obj1->type != GOT_OBJ_TYPE_BLOB) {
378 		err = got_error(GOT_ERR_OBJ_TYPE);
379 		goto done;
380 	}
381 
382 	err = got_object_open(&obj2, repo, id2);
383 	if (err)
384 		goto done;
385 	if (obj2->type != GOT_OBJ_TYPE_BLOB) {
386 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
387 		goto done;
388 	}
389 
390 	err = got_object_blob_open(&blob1, repo, obj1, 8192);
391 	if (err)
392 		goto done;
393 
394 	err = got_object_blob_open(&blob2, repo, obj2, 8192);
395 	if (err)
396 		goto done;
397 
398 	err = cb(cb_arg, blob1, blob2, id1, id2, label1, label2, mode1, mode2,
399 	    repo);
400 done:
401 	if (obj1)
402 		got_object_close(obj1);
403 	if (obj2)
404 		got_object_close(obj2);
405 	if (blob1)
406 		got_object_blob_close(blob1);
407 	if (blob2)
408 		got_object_blob_close(blob2);
409 	return err;
410 }
411 
412 static const struct got_error *
413 diff_deleted_blob(struct got_object_id *id, const char *label, mode_t mode,
414     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
415 {
416 	const struct got_error *err;
417 	struct got_blob_object  *blob = NULL;
418 	struct got_object *obj = NULL;
419 
420 	err = got_object_open(&obj, repo, id);
421 	if (err)
422 		return err;
423 
424 	err = got_object_blob_open(&blob, repo, obj, 8192);
425 	if (err)
426 		goto done;
427 	err = cb(cb_arg, blob, NULL, id, NULL, label, NULL, mode, 0, repo);
428 done:
429 	got_object_close(obj);
430 	if (blob)
431 		got_object_blob_close(blob);
432 	return err;
433 }
434 
435 static const struct got_error *
436 diff_added_tree(struct got_object_id *id, const char *label,
437     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
438     int diff_content)
439 {
440 	const struct got_error *err = NULL;
441 	struct got_object *treeobj = NULL;
442 	struct got_tree_object *tree = NULL;
443 
444 	err = got_object_open(&treeobj, repo, id);
445 	if (err)
446 		goto done;
447 
448 	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
449 		err = got_error(GOT_ERR_OBJ_TYPE);
450 		goto done;
451 	}
452 
453 	err = got_object_tree_open(&tree, repo, treeobj);
454 	if (err)
455 		goto done;
456 
457 	err = got_diff_tree(NULL, tree, NULL, label, repo, cb, cb_arg,
458 	    diff_content);
459 done:
460 	if (tree)
461 		got_object_tree_close(tree);
462 	if (treeobj)
463 		got_object_close(treeobj);
464 	return err;
465 }
466 
467 static const struct got_error *
468 diff_modified_tree(struct got_object_id *id1, struct got_object_id *id2,
469     const char *label1, const char *label2, struct got_repository *repo,
470     got_diff_blob_cb cb, void *cb_arg, int diff_content)
471 {
472 	const struct got_error *err;
473 	struct got_object *treeobj1 = NULL;
474 	struct got_object *treeobj2 = NULL;
475 	struct got_tree_object *tree1 = NULL;
476 	struct got_tree_object *tree2 = NULL;
477 
478 	err = got_object_open(&treeobj1, repo, id1);
479 	if (err)
480 		goto done;
481 
482 	if (treeobj1->type != GOT_OBJ_TYPE_TREE) {
483 		err = got_error(GOT_ERR_OBJ_TYPE);
484 		goto done;
485 	}
486 
487 	err = got_object_open(&treeobj2, repo, id2);
488 	if (err)
489 		goto done;
490 
491 	if (treeobj2->type != GOT_OBJ_TYPE_TREE) {
492 		err = got_error(GOT_ERR_OBJ_TYPE);
493 		goto done;
494 	}
495 
496 	err = got_object_tree_open(&tree1, repo, treeobj1);
497 	if (err)
498 		goto done;
499 
500 	err = got_object_tree_open(&tree2, repo, treeobj2);
501 	if (err)
502 		goto done;
503 
504 	err = got_diff_tree(tree1, tree2, label1, label2, repo, cb, cb_arg,
505 	    diff_content);
506 
507 done:
508 	if (tree1)
509 		got_object_tree_close(tree1);
510 	if (tree2)
511 		got_object_tree_close(tree2);
512 	if (treeobj1)
513 		got_object_close(treeobj1);
514 	if (treeobj2)
515 		got_object_close(treeobj2);
516 	return err;
517 }
518 
519 static const struct got_error *
520 diff_deleted_tree(struct got_object_id *id, const char *label,
521     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
522     int diff_content)
523 {
524 	const struct got_error *err;
525 	struct got_object *treeobj = NULL;
526 	struct got_tree_object *tree = NULL;
527 
528 	err = got_object_open(&treeobj, repo, id);
529 	if (err)
530 		goto done;
531 
532 	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
533 		err = got_error(GOT_ERR_OBJ_TYPE);
534 		goto done;
535 	}
536 
537 	err = got_object_tree_open(&tree, repo, treeobj);
538 	if (err)
539 		goto done;
540 
541 	err = got_diff_tree(tree, NULL, label, NULL, repo, cb, cb_arg,
542 	    diff_content);
543 done:
544 	if (tree)
545 		got_object_tree_close(tree);
546 	if (treeobj)
547 		got_object_close(treeobj);
548 	return err;
549 }
550 
551 static const struct got_error *
552 diff_kind_mismatch(struct got_object_id *id1, struct got_object_id *id2,
553     const char *label1, const char *label2, struct got_repository *repo,
554     got_diff_blob_cb cb, void *cb_arg)
555 {
556 	/* XXX TODO */
557 	return NULL;
558 }
559 
560 static const struct got_error *
561 diff_entry_old_new(struct got_tree_entry *te1,
562     struct got_tree_entry *te2, const char *label1, const char *label2,
563     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
564     int diff_content)
565 {
566 	const struct got_error *err = NULL;
567 	int id_match;
568 
569 	if (got_object_tree_entry_is_submodule(te1))
570 		return NULL;
571 
572 	if (te2 == NULL) {
573 		if (S_ISDIR(te1->mode))
574 			err = diff_deleted_tree(&te1->id, label1, repo,
575 			    cb, cb_arg, diff_content);
576 		else {
577 			if (diff_content)
578 				err = diff_deleted_blob(&te1->id, label1,
579 				    te1->mode, repo, cb, cb_arg);
580 			else
581 				err = cb(cb_arg, NULL, NULL, &te1->id, NULL,
582 				    label1, NULL, te1->mode, 0, repo);
583 		}
584 		return err;
585 	} else if (got_object_tree_entry_is_submodule(te2))
586 		return NULL;
587 
588 	id_match = (got_object_id_cmp(&te1->id, &te2->id) == 0);
589 	if (S_ISDIR(te1->mode) && S_ISDIR(te2->mode)) {
590 		if (!id_match)
591 			return diff_modified_tree(&te1->id, &te2->id,
592 			    label1, label2, repo, cb, cb_arg, diff_content);
593 	} else if ((S_ISREG(te1->mode) || S_ISLNK(te1->mode)) &&
594 	    (S_ISREG(te2->mode) || S_ISLNK(te2->mode))) {
595 		if (!id_match ||
596 		    ((te1->mode & (S_IFLNK | S_IXUSR))) !=
597 		    (te2->mode & (S_IFLNK | S_IXUSR))) {
598 			if (diff_content)
599 				return diff_modified_blob(&te1->id, &te2->id,
600 				    label1, label2, te1->mode, te2->mode,
601 				    repo, cb, cb_arg);
602 			else
603 				return cb(cb_arg, NULL, NULL, &te1->id,
604 				    &te2->id, label1, label2, te1->mode,
605 				    te2->mode, repo);
606 		}
607 	}
608 
609 	if (id_match)
610 		return NULL;
611 
612 	return diff_kind_mismatch(&te1->id, &te2->id, label1, label2, repo,
613 	    cb, cb_arg);
614 }
615 
616 static const struct got_error *
617 diff_entry_new_old(struct got_tree_entry *te2,
618     struct got_tree_entry *te1, const char *label2,
619     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
620     int diff_content)
621 {
622 	if (te1 != NULL) /* handled by diff_entry_old_new() */
623 		return NULL;
624 
625 	if (got_object_tree_entry_is_submodule(te2))
626 		return NULL;
627 
628 	if (S_ISDIR(te2->mode))
629 		return diff_added_tree(&te2->id, label2, repo, cb, cb_arg,
630 		    diff_content);
631 
632 	if (diff_content)
633 		return diff_added_blob(&te2->id, label2, te2->mode, repo, cb,
634 		    cb_arg);
635 
636 	return cb(cb_arg, NULL, NULL, NULL, &te2->id, NULL, label2, 0,
637 	    te2->mode, repo);
638 }
639 
640 const struct got_error *
641 got_diff_tree_collect_changed_paths(void *arg, struct got_blob_object *blob1,
642     struct got_blob_object *blob2, struct got_object_id *id1,
643     struct got_object_id *id2, const char *label1, const char *label2,
644     mode_t mode1, mode_t mode2, struct got_repository *repo)
645 {
646 	const struct got_error *err = NULL;
647 	struct got_pathlist_head *paths = arg;
648 	struct got_diff_changed_path *change = NULL;
649 	char *path = NULL;
650 
651 	path = strdup(label2 ? label2 : label1);
652 	if (path == NULL)
653 		return got_error_from_errno("malloc");
654 
655 	change = malloc(sizeof(*change));
656 	if (change == NULL) {
657 		err = got_error_from_errno("malloc");
658 		goto done;
659 	}
660 
661 	change->status = GOT_STATUS_NO_CHANGE;
662 	if (id1 == NULL)
663 		change->status = GOT_STATUS_ADD;
664 	else if (id2 == NULL)
665 		change->status = GOT_STATUS_DELETE;
666 	else {
667 		if (got_object_id_cmp(id1, id2) != 0)
668 			change->status = GOT_STATUS_MODIFY;
669 		else if (mode1 != mode2)
670 			change->status = GOT_STATUS_MODE_CHANGE;
671 	}
672 
673 	err = got_pathlist_insert(NULL, paths, path, change);
674 done:
675 	if (err) {
676 		free(path);
677 		free(change);
678 	}
679 	return err;
680 }
681 
682 const struct got_error *
683 got_diff_tree(struct got_tree_object *tree1, struct got_tree_object *tree2,
684     const char *label1, const char *label2, struct got_repository *repo,
685     got_diff_blob_cb cb, void *cb_arg, int diff_content)
686 {
687 	const struct got_error *err = NULL;
688 	struct got_tree_entry *te1 = NULL;
689 	struct got_tree_entry *te2 = NULL;
690 	char *l1 = NULL, *l2 = NULL;
691 	int tidx1 = 0, tidx2 = 0;
692 
693 	if (tree1) {
694 		te1 = got_object_tree_get_entry(tree1, 0);
695 		if (te1 && asprintf(&l1, "%s%s%s", label1, label1[0] ? "/" : "",
696 		    te1->name) == -1)
697 			return got_error_from_errno("asprintf");
698 	}
699 	if (tree2) {
700 		te2 = got_object_tree_get_entry(tree2, 0);
701 		if (te2 && asprintf(&l2, "%s%s%s", label2, label2[0] ? "/" : "",
702 		    te2->name) == -1)
703 			return got_error_from_errno("asprintf");
704 	}
705 
706 	do {
707 		if (te1) {
708 			struct got_tree_entry *te = NULL;
709 			if (tree2)
710 				te = got_object_tree_find_entry(tree2,
711 				    te1->name);
712 			if (te) {
713 				free(l2);
714 				l2 = NULL;
715 				if (te && asprintf(&l2, "%s%s%s", label2,
716 				    label2[0] ? "/" : "", te->name) == -1)
717 					return
718 					    got_error_from_errno("asprintf");
719 			}
720 			err = diff_entry_old_new(te1, te, l1, l2, repo, cb,
721 			    cb_arg, diff_content);
722 			if (err)
723 				break;
724 		}
725 
726 		if (te2) {
727 			struct got_tree_entry *te = NULL;
728 			if (tree1)
729 				te = got_object_tree_find_entry(tree1,
730 				    te2->name);
731 			free(l2);
732 			if (te) {
733 				if (asprintf(&l2, "%s%s%s", label2,
734 				    label2[0] ? "/" : "", te->name) == -1)
735 					return
736 					    got_error_from_errno("asprintf");
737 			} else {
738 				if (asprintf(&l2, "%s%s%s", label2,
739 				    label2[0] ? "/" : "", te2->name) == -1)
740 					return
741 					    got_error_from_errno("asprintf");
742 			}
743 			err = diff_entry_new_old(te2, te, l2, repo,
744 			    cb, cb_arg, diff_content);
745 			if (err)
746 				break;
747 		}
748 
749 		free(l1);
750 		l1 = NULL;
751 		if (te1) {
752 			tidx1++;
753 			te1 = got_object_tree_get_entry(tree1, tidx1);
754 			if (te1 &&
755 			    asprintf(&l1, "%s%s%s", label1,
756 			    label1[0] ? "/" : "", te1->name) == -1)
757 				return got_error_from_errno("asprintf");
758 		}
759 		free(l2);
760 		l2 = NULL;
761 		if (te2) {
762 			tidx2++;
763 			te2 = got_object_tree_get_entry(tree2, tidx2);
764 			if (te2 &&
765 			    asprintf(&l2, "%s%s%s", label2,
766 			        label2[0] ? "/" : "", te2->name) == -1)
767 				return got_error_from_errno("asprintf");
768 		}
769 	} while (te1 || te2);
770 
771 	return err;
772 }
773 
774 const struct got_error *
775 got_diff_objects_as_blobs(off_t **line_offsets, size_t *nlines,
776     struct got_object_id *id1, struct got_object_id *id2,
777     const char *label1, const char *label2, int diff_context,
778     int ignore_whitespace, struct got_repository *repo, FILE *outfile)
779 {
780 	const struct got_error *err;
781 	struct got_blob_object *blob1 = NULL, *blob2 = NULL;
782 
783 	if (id1 == NULL && id2 == NULL)
784 		return got_error(GOT_ERR_NO_OBJ);
785 
786 	if (id1) {
787 		err = got_object_open_as_blob(&blob1, repo, id1, 8192);
788 		if (err)
789 			goto done;
790 	}
791 	if (id2) {
792 		err = got_object_open_as_blob(&blob2, repo, id2, 8192);
793 		if (err)
794 			goto done;
795 	}
796 	err = got_diff_blob(line_offsets, nlines, blob1, blob2,
797 	    label1, label2, diff_context, ignore_whitespace, outfile);
798 done:
799 	if (blob1)
800 		got_object_blob_close(blob1);
801 	if (blob2)
802 		got_object_blob_close(blob2);
803 	return err;
804 }
805 
806 const struct got_error *
807 got_diff_objects_as_trees(off_t **line_offsets, size_t *nlines,
808     struct got_object_id *id1, struct got_object_id *id2,
809     char *label1, char *label2, int diff_context, int ignore_whitespace,
810     struct got_repository *repo, FILE *outfile)
811 {
812 	const struct got_error *err;
813 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
814 	struct got_diff_blob_output_unidiff_arg arg;
815 	int want_lineoffsets = (line_offsets != NULL && *line_offsets != NULL);
816 
817 	if (id1 == NULL && id2 == NULL)
818 		return got_error(GOT_ERR_NO_OBJ);
819 
820 	if (id1) {
821 		err = got_object_open_as_tree(&tree1, repo, id1);
822 		if (err)
823 			goto done;
824 	}
825 	if (id2) {
826 		err = got_object_open_as_tree(&tree2, repo, id2);
827 		if (err)
828 			goto done;
829 	}
830 	arg.diff_context = diff_context;
831 	arg.ignore_whitespace = ignore_whitespace;
832 	arg.outfile = outfile;
833 	if (want_lineoffsets) {
834 		arg.line_offsets = *line_offsets;
835 		arg.nlines = *nlines;
836 	} else {
837 		arg.line_offsets = NULL;
838 		arg.nlines = 0;
839 	}
840 	err = got_diff_tree(tree1, tree2, label1, label2, repo,
841 	    got_diff_blob_output_unidiff, &arg, 1);
842 
843 	if (want_lineoffsets) {
844 		*line_offsets = arg.line_offsets; /* was likely re-allocated */
845 		*nlines = arg.nlines;
846 	}
847 done:
848 	if (tree1)
849 		got_object_tree_close(tree1);
850 	if (tree2)
851 		got_object_tree_close(tree2);
852 	return err;
853 }
854 
855 const struct got_error *
856 got_diff_objects_as_commits(off_t **line_offsets, size_t *nlines,
857     struct got_object_id *id1, struct got_object_id *id2,
858     int diff_context, int ignore_whitespace,
859     struct got_repository *repo, FILE *outfile)
860 {
861 	const struct got_error *err;
862 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
863 
864 	if (id2 == NULL)
865 		return got_error(GOT_ERR_NO_OBJ);
866 
867 	if (id1) {
868 		err = got_object_open_as_commit(&commit1, repo, id1);
869 		if (err)
870 			goto done;
871 	}
872 
873 	err = got_object_open_as_commit(&commit2, repo, id2);
874 	if (err)
875 		goto done;
876 
877 	err = got_diff_objects_as_trees(line_offsets, nlines,
878 	    commit1 ? got_object_commit_get_tree_id(commit1) : NULL,
879 	    got_object_commit_get_tree_id(commit2), "", "", diff_context,
880 	    ignore_whitespace, repo, outfile);
881 done:
882 	if (commit1)
883 		got_object_commit_close(commit1);
884 	if (commit2)
885 		got_object_commit_close(commit2);
886 	return err;
887 }
888 
889 const struct got_error *
890 got_diff_files(struct got_diffreg_result **resultp,
891     FILE *f1, const char *label1, FILE *f2, const char *label2,
892     int diff_context, int ignore_whitespace, FILE *outfile)
893 {
894 	const struct got_error *err = NULL;
895 	struct got_diffreg_result *diffreg_result = NULL;
896 
897 	if (resultp)
898 		*resultp = NULL;
899 
900 	if (outfile) {
901 		fprintf(outfile, "file - %s\n",
902 		    f1 == NULL ? "/dev/null" : label1);
903 		fprintf(outfile, "file + %s\n",
904 		    f2 == NULL ? "/dev/null" : label2);
905 	}
906 
907 	err = got_diffreg(&diffreg_result, f1, f2, GOT_DIFF_ALGORITHM_PATIENCE,
908 	    ignore_whitespace);
909 	if (err)
910 		goto done;
911 
912 	if (outfile) {
913 		err = got_diffreg_output(NULL, NULL, diffreg_result,
914 		    f1, f2, label1, label2, GOT_DIFF_OUTPUT_UNIDIFF,
915 		    diff_context, outfile);
916 		if (err)
917 			goto done;
918 	}
919 
920 done:
921 	if (resultp && err == NULL)
922 		*resultp = diffreg_result;
923 	else if (diffreg_result) {
924 		const struct got_error *free_err;
925 		free_err = got_diffreg_result_free(diffreg_result);
926 		if (free_err && err == NULL)
927 			err = free_err;
928 	}
929 
930 	return err;
931 }