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 <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <limits.h>
24 #include <sha1.h>
25 #include <zlib.h>
26 
27 #include "got_object.h"
28 #include "got_repository.h"
29 #include "got_error.h"
30 #include "got_diff.h"
31 #include "got_opentemp.h"
32 #include "got_path.h"
33 
34 #include "got_lib_diff.h"
35 #include "got_lib_delta.h"
36 #include "got_lib_inflate.h"
37 #include "got_lib_object.h"
38 
39 static const struct got_error *
40 diff_blobs(struct got_blob_object *blob1, struct got_blob_object *blob2,
41     const char *label1, const char *label2, int diff_context, FILE *outfile,
42     struct got_diff_changes *changes)
43 {
44 	struct got_diff_state ds;
45 	struct got_diff_args args;
46 	const struct got_error *err = NULL;
47 	FILE *f1 = NULL, *f2 = NULL;
48 	char hex1[SHA1_DIGEST_STRING_LENGTH];
49 	char hex2[SHA1_DIGEST_STRING_LENGTH];
50 	char *idstr1 = NULL, *idstr2 = NULL;
51 	size_t size1, size2;
52 	int res, flags = 0;
53 
54 	if (blob1) {
55 		f1 = got_opentemp();
56 		if (f1 == NULL)
57 			return got_error_from_errno("got_opentemp");
58 	} else
59 		flags |= D_EMPTY1;
60 
61 	if (blob2) {
62 		f2 = got_opentemp();
63 		if (f2 == NULL) {
64 			err = got_error_from_errno("got_opentemp");
65 			fclose(f1);
66 			return err;
67 		}
68 	} else
69 		flags |= D_EMPTY2;
70 
71 	size1 = 0;
72 	if (blob1) {
73 		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
74 		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
75 		    blob1);
76 		if (err)
77 			goto done;
78 	} else
79 		idstr1 = "/dev/null";
80 
81 	size2 = 0;
82 	if (blob2) {
83 		idstr2 = got_object_blob_id_str(blob2, hex2, sizeof(hex2));
84 		err = got_object_blob_dump_to_file(&size2, NULL, NULL, f2,
85 		    blob2);
86 		if (err)
87 			goto done;
88 	} else
89 		idstr2 = "/dev/null";
90 
91 	memset(&ds, 0, sizeof(ds));
92 	/* XXX should stat buffers be passed in args instead of ds? */
93 	ds.stb1.st_mode = S_IFREG;
94 	if (blob1)
95 		ds.stb1.st_size = size1;
96 	ds.stb1.st_mtime = 0; /* XXX */
97 
98 	ds.stb2.st_mode = S_IFREG;
99 	if (blob2)
100 		ds.stb2.st_size = size2;
101 	ds.stb2.st_mtime = 0; /* XXX */
102 
103 	memset(&args, 0, sizeof(args));
104 	args.diff_format = D_UNIFIED;
105 	args.label[0] = label1 ? label1 : idstr1;
106 	args.label[1] = label2 ? label2 : idstr2;
107 	args.diff_context = diff_context;
108 	flags |= D_PROTOTYPE;
109 
110 	if (outfile) {
111 		fprintf(outfile, "blob - %s\n", idstr1);
112 		fprintf(outfile, "blob + %s\n", idstr2);
113 	}
114 	err = got_diffreg(&res, f1, f2, flags, &args, &ds, outfile, changes);
115 	got_diff_state_free(&ds);
116 done:
117 	if (f1 && fclose(f1) != 0 && err == NULL)
118 		err = got_error_from_errno("fclose");
119 	if (f2 && fclose(f2) != 0 && err == NULL)
120 		err = got_error_from_errno("fclose");
121 	return err;
122 }
123 
124 const struct got_error *
125 got_diff_blob_output_unidiff(void *arg, struct got_blob_object *blob1,
126     struct got_blob_object *blob2, struct got_object_id *id1,
127     struct got_object_id *id2, const char *label1, const char *label2,
128     struct got_repository *repo)
129 {
130 	struct got_diff_blob_output_unidiff_arg *a = arg;
131 
132 	return diff_blobs(blob1, blob2, label1, label2, a->diff_context,
133 	    a->outfile, NULL);
134 }
135 
136 const struct got_error *
137 got_diff_blob(struct got_blob_object *blob1, struct got_blob_object *blob2,
138     const char *label1, const char *label2, int diff_context, FILE *outfile)
139 {
140 	return diff_blobs(blob1, blob2, label1, label2, diff_context, outfile,
141 	    NULL);
142 }
143 
144 static const struct got_error *
145 alloc_changes(struct got_diff_changes **changes)
146 {
147 	*changes = calloc(1, sizeof(**changes));
148 	if (*changes == NULL)
149 		return got_error_from_errno("calloc");
150 	SIMPLEQ_INIT(&(*changes)->entries);
151 	return NULL;
152 }
153 
154 static const struct got_error *
155 diff_blob_file(struct got_diff_changes **changes,
156     struct got_blob_object *blob1, const char *label1, FILE *f2, size_t size2,
157     const char *label2, int diff_context, FILE *outfile)
158 {
159 	struct got_diff_state ds;
160 	struct got_diff_args args;
161 	const struct got_error *err = NULL;
162 	FILE *f1 = NULL;
163 	char hex1[SHA1_DIGEST_STRING_LENGTH];
164 	char *idstr1 = NULL;
165 	size_t size1;
166 	int res, flags = 0;
167 
168 	if (changes)
169 		*changes = NULL;
170 
171 	size1 = 0;
172 	if (blob1) {
173 		f1 = got_opentemp();
174 		if (f1 == NULL)
175 			return got_error_from_errno("got_opentemp");
176 		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
177 		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
178 		    blob1);
179 		if (err)
180 			goto done;
181 	} else {
182 		flags |= D_EMPTY1;
183 		idstr1 = "/dev/null";
184 	}
185 
186 	if (f2 == NULL)
187 		flags |= D_EMPTY2;
188 
189 	memset(&ds, 0, sizeof(ds));
190 	/* XXX should stat buffers be passed in args instead of ds? */
191 	ds.stb1.st_mode = S_IFREG;
192 	if (blob1)
193 		ds.stb1.st_size = size1;
194 	ds.stb1.st_mtime = 0; /* XXX */
195 
196 	ds.stb2.st_mode = S_IFREG;
197 	ds.stb2.st_size = size2;
198 	ds.stb2.st_mtime = 0; /* XXX */
199 
200 	memset(&args, 0, sizeof(args));
201 	args.diff_format = D_UNIFIED;
202 	args.label[0] = label2;
203 	args.label[1] = label2;
204 	args.diff_context = diff_context;
205 	flags |= D_PROTOTYPE;
206 
207 	if (outfile) {
208 		fprintf(outfile, "blob - %s\n", label1 ? label1 : idstr1);
209 		fprintf(outfile, "file + %s\n",
210 		    f2 == NULL ? "/dev/null" : label2);
211 	}
212 	if (changes) {
213 		err = alloc_changes(changes);
214 		if (err)
215 			return err;
216 	}
217 	err = got_diffreg(&res, f1, f2, flags, &args, &ds, outfile,
218 	    changes ? *changes : NULL);
219 	got_diff_state_free(&ds);
220 done:
221 	if (f1 && fclose(f1) != 0 && err == NULL)
222 		err = got_error_from_errno("fclose");
223 	return err;
224 }
225 
226 const struct got_error *
227 got_diff_blob_file(struct got_blob_object *blob1, const char *label1,
228     FILE *f2, size_t size2, const char *label2, int diff_context,
229     FILE *outfile)
230 {
231 	return diff_blob_file(NULL, blob1, label1, f2, size2, label2,
232 	    diff_context, outfile);
233 }
234 
235 const struct got_error *
236 got_diff_blob_lines_changed(struct got_diff_changes **changes,
237     struct got_blob_object *blob1, struct got_blob_object *blob2)
238 {
239 	const struct got_error *err = NULL;
240 
241 	err = alloc_changes(changes);
242 	if (err)
243 		return err;
244 
245 	err = diff_blobs(blob1, blob2, NULL, NULL, 3, NULL, *changes);
246 	if (err) {
247 		got_diff_free_changes(*changes);
248 		*changes = NULL;
249 	}
250 	return err;
251 }
252 
253 void
254 got_diff_free_changes(struct got_diff_changes *changes)
255 {
256 	struct got_diff_change *change;
257 	while (!SIMPLEQ_EMPTY(&changes->entries)) {
258 		change = SIMPLEQ_FIRST(&changes->entries);
259 		SIMPLEQ_REMOVE_HEAD(&changes->entries, entry);
260 		free(change);
261 	}
262 	free(changes);
263 }
264 
265 static const struct got_error *
266 diff_added_blob(struct got_object_id *id, const char *label,
267     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
268 {
269 	const struct got_error *err;
270 	struct got_blob_object  *blob = NULL;
271 	struct got_object *obj = NULL;
272 
273 	err = got_object_open(&obj, repo, id);
274 	if (err)
275 		return err;
276 
277 	err = got_object_blob_open(&blob, repo, obj, 8192);
278 	if (err)
279 		goto done;
280 	err = cb(cb_arg, NULL, blob, NULL, id, NULL, label, repo);
281 done:
282 	got_object_close(obj);
283 	if (blob)
284 		got_object_blob_close(blob);
285 	return err;
286 }
287 
288 static const struct got_error *
289 diff_modified_blob(struct got_object_id *id1, struct got_object_id *id2,
290     const char *label1, const char *label2, struct got_repository *repo,
291     got_diff_blob_cb cb, void *cb_arg)
292 {
293 	const struct got_error *err;
294 	struct got_object *obj1 = NULL;
295 	struct got_object *obj2 = NULL;
296 	struct got_blob_object *blob1 = NULL;
297 	struct got_blob_object *blob2 = NULL;
298 
299 	err = got_object_open(&obj1, repo, id1);
300 	if (err)
301 		return err;
302 	if (obj1->type != GOT_OBJ_TYPE_BLOB) {
303 		err = got_error(GOT_ERR_OBJ_TYPE);
304 		goto done;
305 	}
306 
307 	err = got_object_open(&obj2, repo, id2);
308 	if (err)
309 		goto done;
310 	if (obj2->type != GOT_OBJ_TYPE_BLOB) {
311 		err = got_error(GOT_ERR_BAD_OBJ_DATA);
312 		goto done;
313 	}
314 
315 	err = got_object_blob_open(&blob1, repo, obj1, 8192);
316 	if (err)
317 		goto done;
318 
319 	err = got_object_blob_open(&blob2, repo, obj2, 8192);
320 	if (err)
321 		goto done;
322 
323 	err = cb(cb_arg, blob1, blob2, id1, id2, label1, label2, repo);
324 done:
325 	if (obj1)
326 		got_object_close(obj1);
327 	if (obj2)
328 		got_object_close(obj2);
329 	if (blob1)
330 		got_object_blob_close(blob1);
331 	if (blob2)
332 		got_object_blob_close(blob2);
333 	return err;
334 }
335 
336 static const struct got_error *
337 diff_deleted_blob(struct got_object_id *id, const char *label,
338     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
339 {
340 	const struct got_error *err;
341 	struct got_blob_object  *blob = NULL;
342 	struct got_object *obj = NULL;
343 
344 	err = got_object_open(&obj, repo, id);
345 	if (err)
346 		return err;
347 
348 	err = got_object_blob_open(&blob, repo, obj, 8192);
349 	if (err)
350 		goto done;
351 	err = cb(cb_arg, blob, NULL, id, NULL, label, NULL, repo);
352 done:
353 	got_object_close(obj);
354 	if (blob)
355 		got_object_blob_close(blob);
356 	return err;
357 }
358 
359 static const struct got_error *
360 diff_added_tree(struct got_object_id *id, const char *label,
361     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
362     int diff_content)
363 {
364 	const struct got_error *err = NULL;
365 	struct got_object *treeobj = NULL;
366 	struct got_tree_object *tree = NULL;
367 
368 	err = got_object_open(&treeobj, repo, id);
369 	if (err)
370 		goto done;
371 
372 	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
373 		err = got_error(GOT_ERR_OBJ_TYPE);
374 		goto done;
375 	}
376 
377 	err = got_object_tree_open(&tree, repo, treeobj);
378 	if (err)
379 		goto done;
380 
381 	err = got_diff_tree(NULL, tree, NULL, label, repo, cb, cb_arg,
382 	    diff_content);
383 done:
384 	if (tree)
385 		got_object_tree_close(tree);
386 	if (treeobj)
387 		got_object_close(treeobj);
388 	return err;
389 }
390 
391 static const struct got_error *
392 diff_modified_tree(struct got_object_id *id1, struct got_object_id *id2,
393     const char *label1, const char *label2, struct got_repository *repo,
394     got_diff_blob_cb cb, void *cb_arg, int diff_content)
395 {
396 	const struct got_error *err;
397 	struct got_object *treeobj1 = NULL;
398 	struct got_object *treeobj2 = NULL;
399 	struct got_tree_object *tree1 = NULL;
400 	struct got_tree_object *tree2 = NULL;
401 
402 	err = got_object_open(&treeobj1, repo, id1);
403 	if (err)
404 		goto done;
405 
406 	if (treeobj1->type != GOT_OBJ_TYPE_TREE) {
407 		err = got_error(GOT_ERR_OBJ_TYPE);
408 		goto done;
409 	}
410 
411 	err = got_object_open(&treeobj2, repo, id2);
412 	if (err)
413 		goto done;
414 
415 	if (treeobj2->type != GOT_OBJ_TYPE_TREE) {
416 		err = got_error(GOT_ERR_OBJ_TYPE);
417 		goto done;
418 	}
419 
420 	err = got_object_tree_open(&tree1, repo, treeobj1);
421 	if (err)
422 		goto done;
423 
424 	err = got_object_tree_open(&tree2, repo, treeobj2);
425 	if (err)
426 		goto done;
427 
428 	err = got_diff_tree(tree1, tree2, label1, label2, repo, cb, cb_arg,
429 	    diff_content);
430 
431 done:
432 	if (tree1)
433 		got_object_tree_close(tree1);
434 	if (tree2)
435 		got_object_tree_close(tree2);
436 	if (treeobj1)
437 		got_object_close(treeobj1);
438 	if (treeobj2)
439 		got_object_close(treeobj2);
440 	return err;
441 }
442 
443 static const struct got_error *
444 diff_deleted_tree(struct got_object_id *id, const char *label,
445     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
446     int diff_content)
447 {
448 	const struct got_error *err;
449 	struct got_object *treeobj = NULL;
450 	struct got_tree_object *tree = NULL;
451 
452 	err = got_object_open(&treeobj, repo, id);
453 	if (err)
454 		goto done;
455 
456 	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
457 		err = got_error(GOT_ERR_OBJ_TYPE);
458 		goto done;
459 	}
460 
461 	err = got_object_tree_open(&tree, repo, treeobj);
462 	if (err)
463 		goto done;
464 
465 	err = got_diff_tree(tree, NULL, label, NULL, repo, cb, cb_arg,
466 	    diff_content);
467 done:
468 	if (tree)
469 		got_object_tree_close(tree);
470 	if (treeobj)
471 		got_object_close(treeobj);
472 	return err;
473 }
474 
475 static const struct got_error *
476 diff_kind_mismatch(struct got_object_id *id1, struct got_object_id *id2,
477     const char *label1, const char *label2, struct got_repository *repo,
478     got_diff_blob_cb cb, void *cb_arg)
479 {
480 	/* XXX TODO */
481 	return NULL;
482 }
483 
484 static const struct got_error *
485 diff_entry_old_new(const struct got_tree_entry *te1,
486     const struct got_tree_entry *te2, const char *label1, const char *label2,
487     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
488     int diff_content)
489 {
490 	const struct got_error *err = NULL;
491 	int id_match;
492 
493 	if (te2 == NULL) {
494 		if (S_ISDIR(te1->mode))
495 			err = diff_deleted_tree(te1->id, label1, repo,
496 			    cb, cb_arg, diff_content);
497 		else {
498 			if (diff_content)
499 				err = diff_deleted_blob(te1->id, label1, repo,
500 				    cb, cb_arg);
501 			else
502 				err = cb(cb_arg, NULL, NULL, te1->id, NULL,
503 				    label1, NULL, repo);
504 		}
505 		return err;
506 	}
507 
508 	id_match = (got_object_id_cmp(te1->id, te2->id) == 0);
509 	if (S_ISDIR(te1->mode) && S_ISDIR(te2->mode)) {
510 		if (!id_match)
511 			return diff_modified_tree(te1->id, te2->id,
512 			    label1, label2, repo, cb, cb_arg, diff_content);
513 	} else if (S_ISREG(te1->mode) && S_ISREG(te2->mode)) {
514 		if (!id_match) {
515 			if (diff_content)
516 				return diff_modified_blob(te1->id, te2->id,
517 				    label1, label2, repo, cb, cb_arg);
518 			else
519 				return cb(cb_arg, NULL, NULL, te1->id,
520 				    te2->id, label1, label2, repo);
521 		}
522 	}
523 
524 	if (id_match)
525 		return NULL;
526 
527 	return diff_kind_mismatch(te1->id, te2->id, label1, label2, repo,
528 	    cb, cb_arg);
529 }
530 
531 static const struct got_error *
532 diff_entry_new_old(const struct got_tree_entry *te2,
533     const struct got_tree_entry *te1, const char *label2,
534     struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
535     int diff_content)
536 {
537 	if (te1 != NULL) /* handled by diff_entry_old_new() */
538 		return NULL;
539 
540 	if (S_ISDIR(te2->mode))
541 		return diff_added_tree(te2->id, label2, repo, cb, cb_arg,
542 		    diff_content);
543 
544 	if (diff_content)
545 		return diff_added_blob(te2->id, label2, repo, cb, cb_arg);
546 
547 	return cb(cb_arg, NULL, NULL, NULL, te2->id, NULL, label2, repo);
548 }
549 
550 const struct got_error *
551 got_diff_tree(struct got_tree_object *tree1, struct got_tree_object *tree2,
552     const char *label1, const char *label2, struct got_repository *repo,
553     got_diff_blob_cb cb, void *cb_arg, int diff_content)
554 {
555 	const struct got_error *err = NULL;
556 	struct got_tree_entry *te1 = NULL;
557 	struct got_tree_entry *te2 = NULL;
558 	char *l1 = NULL, *l2 = NULL;
559 
560 	if (tree1) {
561 		const struct got_tree_entries *entries;
562 		entries = got_object_tree_get_entries(tree1);
563 		te1 = SIMPLEQ_FIRST(&entries->head);
564 		if (te1 && asprintf(&l1, "%s%s%s", label1, label1[0] ? "/" : "",
565 		    te1->name) == -1)
566 			return got_error_from_errno("asprintf");
567 	}
568 	if (tree2) {
569 		const struct got_tree_entries *entries;
570 		entries = got_object_tree_get_entries(tree2);
571 		te2 = SIMPLEQ_FIRST(&entries->head);
572 		if (te2 && asprintf(&l2, "%s%s%s", label2, label2[0] ? "/" : "",
573 		    te2->name) == -1)
574 			return got_error_from_errno("asprintf");
575 	}
576 
577 	do {
578 		if (te1) {
579 			const struct got_tree_entry *te = NULL;
580 			if (tree2)
581 				te = got_object_tree_find_entry(tree2,
582 				    te1->name);
583 			if (te) {
584 				free(l2);
585 				l2 = NULL;
586 				if (te && asprintf(&l2, "%s%s%s", label2,
587 				    label2[0] ? "/" : "", te->name) == -1)
588 					return
589 					    got_error_from_errno("asprintf");
590 			}
591 			err = diff_entry_old_new(te1, te, l1, l2, repo, cb,
592 			    cb_arg, diff_content);
593 			if (err)
594 				break;
595 		}
596 
597 		if (te2) {
598 			const struct got_tree_entry *te = NULL;
599 			if (tree1)
600 				te = got_object_tree_find_entry(tree1,
601 				    te2->name);
602 			free(l2);
603 			if (te) {
604 				if (asprintf(&l2, "%s%s%s", label2,
605 				    label2[0] ? "/" : "", te->name) == -1)
606 					return
607 					    got_error_from_errno("asprintf");
608 			} else {
609 				if (asprintf(&l2, "%s%s%s", label2,
610 				    label2[0] ? "/" : "", te2->name) == -1)
611 					return
612 					    got_error_from_errno("asprintf");
613 			}
614 			err = diff_entry_new_old(te2, te, l2, repo,
615 			    cb, cb_arg, diff_content);
616 			if (err)
617 				break;
618 		}
619 
620 		free(l1);
621 		l1 = NULL;
622 		if (te1) {
623 			te1 = SIMPLEQ_NEXT(te1, entry);
624 			if (te1 &&
625 			    asprintf(&l1, "%s%s%s", label1,
626 			    label1[0] ? "/" : "", te1->name) == -1)
627 				return got_error_from_errno("asprintf");
628 		}
629 		free(l2);
630 		l2 = NULL;
631 		if (te2) {
632 			te2 = SIMPLEQ_NEXT(te2, entry);
633 			if (te2 &&
634 			    asprintf(&l2, "%s%s%s", label2,
635 			        label2[0] ? "/" : "", te2->name) == -1)
636 				return got_error_from_errno("asprintf");
637 		}
638 	} while (te1 || te2);
639 
640 	return err;
641 }
642 
643 const struct got_error *
644 got_diff_objects_as_blobs(struct got_object_id *id1, struct got_object_id *id2,
645     const char *label1, const char *label2, int diff_context,
646     struct got_repository *repo, FILE *outfile)
647 {
648 	const struct got_error *err;
649 	struct got_blob_object *blob1 = NULL, *blob2 = NULL;
650 
651 	if (id1 == NULL && id2 == NULL)
652 		return got_error(GOT_ERR_NO_OBJ);
653 
654 	if (id1) {
655 		err = got_object_open_as_blob(&blob1, repo, id1, 8192);
656 		if (err)
657 			goto done;
658 	}
659 	if (id2) {
660 		err = got_object_open_as_blob(&blob2, repo, id2, 8192);
661 		if (err)
662 			goto done;
663 	}
664 	err = got_diff_blob(blob1, blob2, label1, label2, diff_context,
665 	    outfile);
666 done:
667 	if (blob1)
668 		got_object_blob_close(blob1);
669 	if (blob2)
670 		got_object_blob_close(blob2);
671 	return err;
672 }
673 
674 const struct got_error *
675 got_diff_objects_as_trees(struct got_object_id *id1, struct got_object_id *id2,
676     char *label1, char *label2, int diff_context, struct got_repository *repo,
677     FILE *outfile)
678 {
679 	const struct got_error *err;
680 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
681 	struct got_diff_blob_output_unidiff_arg arg;
682 
683 	if (id1 == NULL && id2 == NULL)
684 		return got_error(GOT_ERR_NO_OBJ);
685 
686 	if (id1) {
687 		err = got_object_open_as_tree(&tree1, repo, id1);
688 		if (err)
689 			goto done;
690 	}
691 	if (id2) {
692 		err = got_object_open_as_tree(&tree2, repo, id2);
693 		if (err)
694 			goto done;
695 	}
696 	arg.diff_context = diff_context;
697 	arg.outfile = outfile;
698 	err = got_diff_tree(tree1, tree2, label1, label2, repo,
699 	    got_diff_blob_output_unidiff, &arg, 1);
700 done:
701 	if (tree1)
702 		got_object_tree_close(tree1);
703 	if (tree2)
704 		got_object_tree_close(tree2);
705 	return err;
706 }
707 
708 const struct got_error *
709 got_diff_objects_as_commits(struct got_object_id *id1,
710     struct got_object_id *id2, int diff_context,
711     struct got_repository *repo, FILE *outfile)
712 {
713 	const struct got_error *err;
714 	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
715 
716 	if (id2 == NULL)
717 		return got_error(GOT_ERR_NO_OBJ);
718 
719 	if (id1) {
720 		err = got_object_open_as_commit(&commit1, repo, id1);
721 		if (err)
722 			goto done;
723 	}
724 
725 	err = got_object_open_as_commit(&commit2, repo, id2);
726 	if (err)
727 		goto done;
728 
729 	err = got_diff_objects_as_trees(
730 	    commit1 ? got_object_commit_get_tree_id(commit1) : NULL,
731 	    got_object_commit_get_tree_id(commit2), "", "", diff_context, repo,
732 	    outfile);
733 done:
734 	if (commit1)
735 		got_object_commit_close(commit1);
736 	if (commit2)
737 		got_object_commit_close(commit2);
738 	return err;
739 }
740 
741 const struct got_error *
742 got_diff_files(struct got_diff_changes **changes,
743     struct got_diff_state **ds,
744     struct got_diff_args **args,
745     int *flags,
746     FILE *f1, size_t size1, const char *label1,
747     FILE *f2, size_t size2, const char *label2,
748     int diff_context, FILE *outfile)
749 {
750 	const struct got_error *err = NULL;
751 	int res;
752 
753 	*flags = 0;
754 	*ds = calloc(1, sizeof(**ds));
755 	if (*ds == NULL)
756 		return got_error_from_errno("calloc");
757 	*args = calloc(1, sizeof(**args));
758 	if (*args == NULL) {
759 		err = got_error_from_errno("calloc");
760 		goto done;
761 	}
762 
763 	if (changes)
764 		*changes = NULL;
765 
766 	if (f1 == NULL)
767 		*flags |= D_EMPTY1;
768 
769 	if (f2 == NULL)
770 		*flags |= D_EMPTY2;
771 
772 	/* XXX should stat buffers be passed in args instead of ds? */
773 	(*ds)->stb1.st_mode = S_IFREG;
774 	(*ds)->stb1.st_size = size1;
775 	(*ds)->stb1.st_mtime = 0; /* XXX */
776 
777 	(*ds)->stb2.st_mode = S_IFREG;
778 	(*ds)->stb2.st_size = size2;
779 	(*ds)->stb2.st_mtime = 0; /* XXX */
780 
781 	(*args)->diff_format = D_UNIFIED;
782 	(*args)->label[0] = label1;
783 	(*args)->label[1] = label2;
784 	(*args)->diff_context = diff_context;
785 	*flags |= D_PROTOTYPE;
786 
787 	if (outfile) {
788 		fprintf(outfile, "file - %s\n",
789 		    f1 == NULL ? "/dev/null" : label1);
790 		fprintf(outfile, "file + %s\n",
791 		    f2 == NULL ? "/dev/null" : label2);
792 	}
793 	if (changes) {
794 		err = alloc_changes(changes);
795 		if (err)
796 			goto done;
797 	}
798 	err = got_diffreg(&res, f1, f2, *flags, *args, *ds, outfile,
799 	    changes ? *changes : NULL);
800 done:
801 	if (err) {
802 		if (*ds) {
803 			got_diff_state_free(*ds);
804 			free(*ds);
805 			*ds = NULL;
806 		}
807 		if (*args) {
808 			free(*args);
809 			*args = NULL;
810 		}
811 		if (changes) {
812 			if (*changes)
813 				got_diff_free_changes(*changes);
814 			*changes = NULL;
815 		}
816 	}
817 	return err;
818 }