Merge branch 'jn/gitweb-grep'
[git/git.git] / diff-lib.c
1 /*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4 #include "cache.h"
5 #include "quote.h"
6 #include "commit.h"
7 #include "diff.h"
8 #include "diffcore.h"
9 #include "revision.h"
10 #include "cache-tree.h"
11 #include "path-list.h"
12 #include "unpack-trees.h"
13
14 /*
15 * diff-files
16 */
17
18 static int read_directory(const char *path, struct path_list *list)
19 {
20 DIR *dir;
21 struct dirent *e;
22
23 if (!(dir = opendir(path)))
24 return error("Could not open directory %s", path);
25
26 while ((e = readdir(dir)))
27 if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
28 path_list_insert(e->d_name, list);
29
30 closedir(dir);
31 return 0;
32 }
33
34 static int get_mode(const char *path, int *mode)
35 {
36 struct stat st;
37
38 if (!path || !strcmp(path, "/dev/null"))
39 *mode = 0;
40 else if (!strcmp(path, "-"))
41 *mode = create_ce_mode(0666);
42 else if (stat(path, &st))
43 return error("Could not access '%s'", path);
44 else
45 *mode = st.st_mode;
46 return 0;
47 }
48
49 static int queue_diff(struct diff_options *o,
50 const char *name1, const char *name2)
51 {
52 int mode1 = 0, mode2 = 0;
53
54 if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
55 return -1;
56
57 if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
58 return error("file/directory conflict: %s, %s", name1, name2);
59
60 if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
61 char buffer1[PATH_MAX], buffer2[PATH_MAX];
62 struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
63 int len1 = 0, len2 = 0, i1, i2, ret = 0;
64
65 if (name1 && read_directory(name1, &p1))
66 return -1;
67 if (name2 && read_directory(name2, &p2)) {
68 path_list_clear(&p1, 0);
69 return -1;
70 }
71
72 if (name1) {
73 len1 = strlen(name1);
74 if (len1 > 0 && name1[len1 - 1] == '/')
75 len1--;
76 memcpy(buffer1, name1, len1);
77 buffer1[len1++] = '/';
78 }
79
80 if (name2) {
81 len2 = strlen(name2);
82 if (len2 > 0 && name2[len2 - 1] == '/')
83 len2--;
84 memcpy(buffer2, name2, len2);
85 buffer2[len2++] = '/';
86 }
87
88 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
89 const char *n1, *n2;
90 int comp;
91
92 if (i1 == p1.nr)
93 comp = 1;
94 else if (i2 == p2.nr)
95 comp = -1;
96 else
97 comp = strcmp(p1.items[i1].path,
98 p2.items[i2].path);
99
100 if (comp > 0)
101 n1 = NULL;
102 else {
103 n1 = buffer1;
104 strncpy(buffer1 + len1, p1.items[i1++].path,
105 PATH_MAX - len1);
106 }
107
108 if (comp < 0)
109 n2 = NULL;
110 else {
111 n2 = buffer2;
112 strncpy(buffer2 + len2, p2.items[i2++].path,
113 PATH_MAX - len2);
114 }
115
116 ret = queue_diff(o, n1, n2);
117 }
118 path_list_clear(&p1, 0);
119 path_list_clear(&p2, 0);
120
121 return ret;
122 } else {
123 struct diff_filespec *d1, *d2;
124
125 if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
126 unsigned tmp;
127 const char *tmp_c;
128 tmp = mode1; mode1 = mode2; mode2 = tmp;
129 tmp_c = name1; name1 = name2; name2 = tmp_c;
130 }
131
132 if (!name1)
133 name1 = "/dev/null";
134 if (!name2)
135 name2 = "/dev/null";
136 d1 = alloc_filespec(name1);
137 d2 = alloc_filespec(name2);
138 fill_filespec(d1, null_sha1, mode1);
139 fill_filespec(d2, null_sha1, mode2);
140
141 diff_queue(&diff_queued_diff, d1, d2);
142 return 0;
143 }
144 }
145
146 /*
147 * Does the path name a blob in the working tree, or a directory
148 * in the working tree?
149 */
150 static int is_in_index(const char *path)
151 {
152 int len, pos;
153 struct cache_entry *ce;
154
155 len = strlen(path);
156 while (path[len-1] == '/')
157 len--;
158 if (!len)
159 return 1; /* "." */
160 pos = cache_name_pos(path, len);
161 if (0 <= pos)
162 return 1;
163 pos = -1 - pos;
164 while (pos < active_nr) {
165 ce = active_cache[pos++];
166 if (ce_namelen(ce) <= len ||
167 strncmp(ce->name, path, len) ||
168 (ce->name[len] > '/'))
169 break; /* path cannot be a prefix */
170 if (ce->name[len] == '/')
171 return 1;
172 }
173 return 0;
174 }
175
176 static int handle_diff_files_args(struct rev_info *revs,
177 int argc, const char **argv,
178 unsigned int *options)
179 {
180 *options = 0;
181
182 /* revs->max_count == -2 means --no-index */
183 while (1 < argc && argv[1][0] == '-') {
184 if (!strcmp(argv[1], "--base"))
185 revs->max_count = 1;
186 else if (!strcmp(argv[1], "--ours"))
187 revs->max_count = 2;
188 else if (!strcmp(argv[1], "--theirs"))
189 revs->max_count = 3;
190 else if (!strcmp(argv[1], "-n") ||
191 !strcmp(argv[1], "--no-index")) {
192 revs->max_count = -2;
193 DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
194 DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
195 }
196 else if (!strcmp(argv[1], "-q"))
197 *options |= DIFF_SILENT_ON_REMOVED;
198 else
199 return error("invalid option: %s", argv[1]);
200 argv++; argc--;
201 }
202
203 if (revs->max_count == -1 && revs->diffopt.nr_paths == 2) {
204 /*
205 * If two files are specified, and at least one is untracked,
206 * default to no-index.
207 */
208 read_cache();
209 if (!is_in_index(revs->diffopt.paths[0]) ||
210 !is_in_index(revs->diffopt.paths[1])) {
211 revs->max_count = -2;
212 DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
213 }
214 }
215
216 /*
217 * Make sure there are NO revision (i.e. pending object) parameter,
218 * rev.max_count is reasonable (0 <= n <= 3),
219 * there is no other revision filtering parameters.
220 */
221 if (revs->pending.nr || revs->max_count > 3 ||
222 revs->min_age != -1 || revs->max_age != -1)
223 return error("no revision allowed with diff-files");
224
225 if (revs->max_count == -1 &&
226 (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
227 revs->combine_merges = revs->dense_combined_merges = 1;
228
229 return 0;
230 }
231
232 static int is_outside_repo(const char *path, int nongit, const char *prefix)
233 {
234 int i;
235 if (nongit || !strcmp(path, "-") || is_absolute_path(path))
236 return 1;
237 if (prefixcmp(path, "../"))
238 return 0;
239 if (!prefix)
240 return 1;
241 for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
242 while (i > 0 && prefix[i - 1] != '/')
243 i--;
244 if (--i < 0)
245 return 1;
246 path += 3;
247 }
248 return 0;
249 }
250
251 int setup_diff_no_index(struct rev_info *revs,
252 int argc, const char ** argv, int nongit, const char *prefix)
253 {
254 int i;
255 for (i = 1; i < argc; i++)
256 if (argv[i][0] != '-' || argv[i][1] == '\0')
257 break;
258 else if (!strcmp(argv[i], "--")) {
259 i++;
260 break;
261 } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
262 i = argc - 3;
263 DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
264 break;
265 }
266 if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
267 !is_outside_repo(argv[i], nongit, prefix)))
268 return -1;
269
270 diff_setup(&revs->diffopt);
271 for (i = 1; i < argc - 2; )
272 if (!strcmp(argv[i], "--no-index"))
273 i++;
274 else {
275 int j = diff_opt_parse(&revs->diffopt,
276 argv + i, argc - i);
277 if (!j)
278 die("invalid diff option/value: %s", argv[i]);
279 i += j;
280 }
281
282 if (prefix) {
283 int len = strlen(prefix);
284
285 revs->diffopt.paths = xcalloc(2, sizeof(char*));
286 for (i = 0; i < 2; i++) {
287 const char *p = argv[argc - 2 + i];
288 /*
289 * stdin should be spelled as '-'; if you have
290 * path that is '-', spell it as ./-.
291 */
292 p = (strcmp(p, "-")
293 ? xstrdup(prefix_filename(prefix, len, p))
294 : p);
295 revs->diffopt.paths[i] = p;
296 }
297 }
298 else
299 revs->diffopt.paths = argv + argc - 2;
300 revs->diffopt.nr_paths = 2;
301 DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
302 revs->max_count = -2;
303 if (diff_setup_done(&revs->diffopt) < 0)
304 die("diff_setup_done failed");
305 return 0;
306 }
307
308 int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
309 {
310 unsigned int options;
311
312 if (handle_diff_files_args(revs, argc, argv, &options))
313 return -1;
314
315 if (DIFF_OPT_TST(&revs->diffopt, NO_INDEX)) {
316 if (revs->diffopt.nr_paths != 2)
317 return error("need two files/directories with --no-index");
318 if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
319 revs->diffopt.paths[1]))
320 return -1;
321 diffcore_std(&revs->diffopt);
322 diff_flush(&revs->diffopt);
323 /*
324 * The return code for --no-index imitates diff(1):
325 * 0 = no changes, 1 = changes, else error
326 */
327 return revs->diffopt.found_changes;
328 }
329
330 if (read_cache() < 0) {
331 perror("read_cache");
332 return -1;
333 }
334 return run_diff_files(revs, options);
335 }
336
337 int run_diff_files(struct rev_info *revs, unsigned int option)
338 {
339 int entries, i;
340 int diff_unmerged_stage = revs->max_count;
341 int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
342 unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
343 ? CE_MATCH_RACY_IS_DIRTY : 0);
344
345 if (diff_unmerged_stage < 0)
346 diff_unmerged_stage = 2;
347 entries = active_nr;
348 for (i = 0; i < entries; i++) {
349 struct stat st;
350 unsigned int oldmode, newmode;
351 struct cache_entry *ce = active_cache[i];
352 int changed;
353
354 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
355 DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
356 break;
357
358 if (!ce_path_match(ce, revs->prune_data))
359 continue;
360
361 if (ce_stage(ce)) {
362 struct combine_diff_path *dpath;
363 int num_compare_stages = 0;
364 size_t path_len;
365
366 path_len = ce_namelen(ce);
367
368 dpath = xmalloc(combine_diff_path_size(5, path_len));
369 dpath->path = (char *) &(dpath->parent[5]);
370
371 dpath->next = NULL;
372 dpath->len = path_len;
373 memcpy(dpath->path, ce->name, path_len);
374 dpath->path[path_len] = '\0';
375 hashclr(dpath->sha1);
376 memset(&(dpath->parent[0]), 0,
377 sizeof(struct combine_diff_parent)*5);
378
379 if (lstat(ce->name, &st) < 0) {
380 if (errno != ENOENT && errno != ENOTDIR) {
381 perror(ce->name);
382 continue;
383 }
384 if (silent_on_removed)
385 continue;
386 }
387 else
388 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
389
390 while (i < entries) {
391 struct cache_entry *nce = active_cache[i];
392 int stage;
393
394 if (strcmp(ce->name, nce->name))
395 break;
396
397 /* Stage #2 (ours) is the first parent,
398 * stage #3 (theirs) is the second.
399 */
400 stage = ce_stage(nce);
401 if (2 <= stage) {
402 int mode = nce->ce_mode;
403 num_compare_stages++;
404 hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
405 dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
406 dpath->parent[stage-2].status =
407 DIFF_STATUS_MODIFIED;
408 }
409
410 /* diff against the proper unmerged stage */
411 if (stage == diff_unmerged_stage)
412 ce = nce;
413 i++;
414 }
415 /*
416 * Compensate for loop update
417 */
418 i--;
419
420 if (revs->combine_merges && num_compare_stages == 2) {
421 show_combined_diff(dpath, 2,
422 revs->dense_combined_merges,
423 revs);
424 free(dpath);
425 continue;
426 }
427 free(dpath);
428 dpath = NULL;
429
430 /*
431 * Show the diff for the 'ce' if we found the one
432 * from the desired stage.
433 */
434 diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
435 if (ce_stage(ce) != diff_unmerged_stage)
436 continue;
437 }
438
439 if (ce_uptodate(ce))
440 continue;
441 if (lstat(ce->name, &st) < 0) {
442 if (errno != ENOENT && errno != ENOTDIR) {
443 perror(ce->name);
444 continue;
445 }
446 if (silent_on_removed)
447 continue;
448 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
449 ce->sha1, ce->name, NULL);
450 continue;
451 }
452 changed = ce_match_stat(ce, &st, ce_option);
453 if (!changed && !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
454 continue;
455 oldmode = ce->ce_mode;
456 newmode = ce_mode_from_stat(ce, st.st_mode);
457 diff_change(&revs->diffopt, oldmode, newmode,
458 ce->sha1, (changed ? null_sha1 : ce->sha1),
459 ce->name, NULL);
460
461 }
462 diffcore_std(&revs->diffopt);
463 diff_flush(&revs->diffopt);
464 return 0;
465 }
466
467 /*
468 * diff-index
469 */
470
471 /* A file entry went away or appeared */
472 static void diff_index_show_file(struct rev_info *revs,
473 const char *prefix,
474 struct cache_entry *ce,
475 const unsigned char *sha1, unsigned int mode)
476 {
477 diff_addremove(&revs->diffopt, prefix[0], mode,
478 sha1, ce->name, NULL);
479 }
480
481 static int get_stat_data(struct cache_entry *ce,
482 const unsigned char **sha1p,
483 unsigned int *modep,
484 int cached, int match_missing)
485 {
486 const unsigned char *sha1 = ce->sha1;
487 unsigned int mode = ce->ce_mode;
488
489 if (!cached) {
490 int changed;
491 struct stat st;
492 if (lstat(ce->name, &st) < 0) {
493 if (errno == ENOENT && match_missing) {
494 *sha1p = sha1;
495 *modep = mode;
496 return 0;
497 }
498 return -1;
499 }
500 changed = ce_match_stat(ce, &st, 0);
501 if (changed) {
502 mode = ce_mode_from_stat(ce, st.st_mode);
503 sha1 = null_sha1;
504 }
505 }
506
507 *sha1p = sha1;
508 *modep = mode;
509 return 0;
510 }
511
512 static void show_new_file(struct rev_info *revs,
513 struct cache_entry *new,
514 int cached, int match_missing)
515 {
516 const unsigned char *sha1;
517 unsigned int mode;
518
519 /* New file in the index: it might actually be different in
520 * the working copy.
521 */
522 if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
523 return;
524
525 diff_index_show_file(revs, "+", new, sha1, mode);
526 }
527
528 static int show_modified(struct rev_info *revs,
529 struct cache_entry *old,
530 struct cache_entry *new,
531 int report_missing,
532 int cached, int match_missing)
533 {
534 unsigned int mode, oldmode;
535 const unsigned char *sha1;
536
537 if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
538 if (report_missing)
539 diff_index_show_file(revs, "-", old,
540 old->sha1, old->ce_mode);
541 return -1;
542 }
543
544 if (revs->combine_merges && !cached &&
545 (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
546 struct combine_diff_path *p;
547 int pathlen = ce_namelen(new);
548
549 p = xmalloc(combine_diff_path_size(2, pathlen));
550 p->path = (char *) &p->parent[2];
551 p->next = NULL;
552 p->len = pathlen;
553 memcpy(p->path, new->name, pathlen);
554 p->path[pathlen] = 0;
555 p->mode = mode;
556 hashclr(p->sha1);
557 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
558 p->parent[0].status = DIFF_STATUS_MODIFIED;
559 p->parent[0].mode = new->ce_mode;
560 hashcpy(p->parent[0].sha1, new->sha1);
561 p->parent[1].status = DIFF_STATUS_MODIFIED;
562 p->parent[1].mode = old->ce_mode;
563 hashcpy(p->parent[1].sha1, old->sha1);
564 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
565 free(p);
566 return 0;
567 }
568
569 oldmode = old->ce_mode;
570 if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
571 !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
572 return 0;
573
574 diff_change(&revs->diffopt, oldmode, mode,
575 old->sha1, sha1, old->name, NULL);
576 return 0;
577 }
578
579 /*
580 * This turns all merge entries into "stage 3". That guarantees that
581 * when we read in the new tree (into "stage 1"), we won't lose sight
582 * of the fact that we had unmerged entries.
583 */
584 static void mark_merge_entries(void)
585 {
586 int i;
587 for (i = 0; i < active_nr; i++) {
588 struct cache_entry *ce = active_cache[i];
589 if (!ce_stage(ce))
590 continue;
591 ce->ce_flags |= CE_STAGEMASK;
592 }
593 }
594
595 /*
596 * This gets a mix of an existing index and a tree, one pathname entry
597 * at a time. The index entry may be a single stage-0 one, but it could
598 * also be multiple unmerged entries (in which case idx_pos/idx_nr will
599 * give you the position and number of entries in the index).
600 */
601 static void do_oneway_diff(struct unpack_trees_options *o,
602 struct cache_entry *idx,
603 struct cache_entry *tree,
604 int idx_pos, int idx_nr)
605 {
606 struct rev_info *revs = o->unpack_data;
607 int match_missing, cached;
608
609 /*
610 * Backward compatibility wart - "diff-index -m" does
611 * not mean "do not ignore merges", but "match_missing".
612 *
613 * But with the revision flag parsing, that's found in
614 * "!revs->ignore_merges".
615 */
616 cached = o->index_only;
617 match_missing = !revs->ignore_merges;
618
619 if (cached && idx && ce_stage(idx)) {
620 if (tree)
621 diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
622 return;
623 }
624
625 /*
626 * Something added to the tree?
627 */
628 if (!tree) {
629 show_new_file(revs, idx, cached, match_missing);
630 return;
631 }
632
633 /*
634 * Something removed from the tree?
635 */
636 if (!idx) {
637 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
638 return;
639 }
640
641 /* Show difference between old and new */
642 show_modified(revs, tree, idx, 1, cached, match_missing);
643 }
644
645 /*
646 * Count how many index entries go with the first one
647 */
648 static inline int count_skip(const struct cache_entry *src, int pos)
649 {
650 int skip = 1;
651
652 /* We can only have multiple entries if the first one is not stage-0 */
653 if (ce_stage(src)) {
654 struct cache_entry **p = active_cache + pos;
655 int namelen = ce_namelen(src);
656
657 for (;;) {
658 const struct cache_entry *ce;
659 pos++;
660 if (pos >= active_nr)
661 break;
662 ce = *++p;
663 if (ce_namelen(ce) != namelen)
664 break;
665 if (memcmp(ce->name, src->name, namelen))
666 break;
667 skip++;
668 }
669 }
670 return skip;
671 }
672
673 /*
674 * The unpack_trees() interface is designed for merging, so
675 * the different source entries are designed primarily for
676 * the source trees, with the old index being really mainly
677 * used for being replaced by the result.
678 *
679 * For diffing, the index is more important, and we only have a
680 * single tree.
681 *
682 * We're supposed to return how many index entries we want to skip.
683 *
684 * This wrapper makes it all more readable, and takes care of all
685 * the fairly complex unpack_trees() semantic requirements, including
686 * the skipping, the path matching, the type conflict cases etc.
687 */
688 static int oneway_diff(struct cache_entry **src,
689 struct unpack_trees_options *o,
690 int index_pos)
691 {
692 int skip = 0;
693 struct cache_entry *idx = src[0];
694 struct cache_entry *tree = src[1];
695 struct rev_info *revs = o->unpack_data;
696
697 if (index_pos >= 0)
698 skip = count_skip(idx, index_pos);
699
700 /*
701 * Unpack-trees generates a DF/conflict entry if
702 * there was a directory in the index and a tree
703 * in the tree. From a diff standpoint, that's a
704 * delete of the tree and a create of the file.
705 */
706 if (tree == o->df_conflict_entry)
707 tree = NULL;
708
709 if (ce_path_match(idx ? idx : tree, revs->prune_data))
710 do_oneway_diff(o, idx, tree, index_pos, skip);
711
712 return skip;
713 }
714
715 int run_diff_index(struct rev_info *revs, int cached)
716 {
717 struct object *ent;
718 struct tree *tree;
719 const char *tree_name;
720 struct unpack_trees_options opts;
721 struct tree_desc t;
722
723 mark_merge_entries();
724
725 ent = revs->pending.objects[0].item;
726 tree_name = revs->pending.objects[0].name;
727 tree = parse_tree_indirect(ent->sha1);
728 if (!tree)
729 return error("bad tree object %s", tree_name);
730
731 memset(&opts, 0, sizeof(opts));
732 opts.head_idx = 1;
733 opts.index_only = cached;
734 opts.merge = 1;
735 opts.fn = oneway_diff;
736 opts.unpack_data = revs;
737
738 init_tree_desc(&t, tree->buffer, tree->size);
739 if (unpack_trees(1, &t, &opts))
740 exit(128);
741
742 diffcore_std(&revs->diffopt);
743 diff_flush(&revs->diffopt);
744 return 0;
745 }
746
747 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
748 {
749 struct tree *tree;
750 struct rev_info revs;
751 int i;
752 struct cache_entry **dst;
753 struct cache_entry *last = NULL;
754 struct unpack_trees_options opts;
755 struct tree_desc t;
756
757 /*
758 * This is used by git-blame to run diff-cache internally;
759 * it potentially needs to repeatedly run this, so we will
760 * start by removing the higher order entries the last round
761 * left behind.
762 */
763 dst = active_cache;
764 for (i = 0; i < active_nr; i++) {
765 struct cache_entry *ce = active_cache[i];
766 if (ce_stage(ce)) {
767 if (last && !strcmp(ce->name, last->name))
768 continue;
769 cache_tree_invalidate_path(active_cache_tree,
770 ce->name);
771 last = ce;
772 ce->ce_flags |= CE_REMOVE;
773 }
774 *dst++ = ce;
775 }
776 active_nr = dst - active_cache;
777
778 init_revisions(&revs, NULL);
779 revs.prune_data = opt->paths;
780 tree = parse_tree_indirect(tree_sha1);
781 if (!tree)
782 die("bad tree object %s", sha1_to_hex(tree_sha1));
783
784 memset(&opts, 0, sizeof(opts));
785 opts.head_idx = 1;
786 opts.index_only = 1;
787 opts.merge = 1;
788 opts.fn = oneway_diff;
789 opts.unpack_data = &revs;
790
791 init_tree_desc(&t, tree->buffer, tree->size);
792 if (unpack_trees(1, &t, &opts))
793 exit(128);
794 return 0;
795 }