Merge branch 'maint' of git://repo.or.cz/git-gui into maint
[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
13 /*
14  * diff-files
15  */
16
17 static int read_directory(const char *path, struct path_list *list)
18 {
19         DIR *dir;
20         struct dirent *e;
21
22         if (!(dir = opendir(path)))
23                 return error("Could not open directory %s", path);
24
25         while ((e = readdir(dir)))
26                 if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
27                         path_list_insert(e->d_name, list);
28
29         closedir(dir);
30         return 0;
31 }
32
33 static int get_mode(const char *path, int *mode)
34 {
35         struct stat st;
36
37         if (!path || !strcmp(path, "/dev/null"))
38                 *mode = 0;
39         else if (!strcmp(path, "-"))
40                 *mode = ntohl(create_ce_mode(0666));
41         else if (stat(path, &st))
42                 return error("Could not access '%s'", path);
43         else
44                 *mode = st.st_mode;
45         return 0;
46 }
47
48 static int queue_diff(struct diff_options *o,
49                 const char *name1, const char *name2)
50 {
51         int mode1 = 0, mode2 = 0;
52
53         if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
54                 return -1;
55
56         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
57                 return error("file/directory conflict: %s, %s", name1, name2);
58
59         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
60                 char buffer1[PATH_MAX], buffer2[PATH_MAX];
61                 struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
62                 int len1 = 0, len2 = 0, i1, i2, ret = 0;
63
64                 if (name1 && read_directory(name1, &p1))
65                         return -1;
66                 if (name2 && read_directory(name2, &p2)) {
67                         path_list_clear(&p1, 0);
68                         return -1;
69                 }
70
71                 if (name1) {
72                         len1 = strlen(name1);
73                         if (len1 > 0 && name1[len1 - 1] == '/')
74                                 len1--;
75                         memcpy(buffer1, name1, len1);
76                         buffer1[len1++] = '/';
77                 }
78
79                 if (name2) {
80                         len2 = strlen(name2);
81                         if (len2 > 0 && name2[len2 - 1] == '/')
82                                 len2--;
83                         memcpy(buffer2, name2, len2);
84                         buffer2[len2++] = '/';
85                 }
86
87                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
88                         const char *n1, *n2;
89                         int comp;
90
91                         if (i1 == p1.nr)
92                                 comp = 1;
93                         else if (i2 == p2.nr)
94                                 comp = -1;
95                         else
96                                 comp = strcmp(p1.items[i1].path,
97                                         p2.items[i2].path);
98
99                         if (comp > 0)
100                                 n1 = NULL;
101                         else {
102                                 n1 = buffer1;
103                                 strncpy(buffer1 + len1, p1.items[i1++].path,
104                                                 PATH_MAX - len1);
105                         }
106
107                         if (comp < 0)
108                                 n2 = NULL;
109                         else {
110                                 n2 = buffer2;
111                                 strncpy(buffer2 + len2, p2.items[i2++].path,
112                                                 PATH_MAX - len2);
113                         }
114
115                         ret = queue_diff(o, n1, n2);
116                 }
117                 path_list_clear(&p1, 0);
118                 path_list_clear(&p2, 0);
119
120                 return ret;
121         } else {
122                 struct diff_filespec *d1, *d2;
123
124                 if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
125                         unsigned tmp;
126                         const char *tmp_c;
127                         tmp = mode1; mode1 = mode2; mode2 = tmp;
128                         tmp_c = name1; name1 = name2; name2 = tmp_c;
129                 }
130
131                 if (!name1)
132                         name1 = "/dev/null";
133                 if (!name2)
134                         name2 = "/dev/null";
135                 d1 = alloc_filespec(name1);
136                 d2 = alloc_filespec(name2);
137                 fill_filespec(d1, null_sha1, mode1);
138                 fill_filespec(d2, null_sha1, mode2);
139
140                 diff_queue(&diff_queued_diff, d1, d2);
141                 return 0;
142         }
143 }
144
145 /*
146  * Does the path name a blob in the working tree, or a directory
147  * in the working tree?
148  */
149 static int is_in_index(const char *path)
150 {
151         int len, pos;
152         struct cache_entry *ce;
153
154         len = strlen(path);
155         while (path[len-1] == '/')
156                 len--;
157         if (!len)
158                 return 1; /* "." */
159         pos = cache_name_pos(path, len);
160         if (0 <= pos)
161                 return 1;
162         pos = -1 - pos;
163         while (pos < active_nr) {
164                 ce = active_cache[pos++];
165                 if (ce_namelen(ce) <= len ||
166                     strncmp(ce->name, path, len) ||
167                     (ce->name[len] > '/'))
168                         break; /* path cannot be a prefix */
169                 if (ce->name[len] == '/')
170                         return 1;
171         }
172         return 0;
173 }
174
175 static int handle_diff_files_args(struct rev_info *revs,
176                                   int argc, const char **argv,
177                                   unsigned int *options)
178 {
179         *options = 0;
180
181         /* revs->max_count == -2 means --no-index */
182         while (1 < argc && argv[1][0] == '-') {
183                 if (!strcmp(argv[1], "--base"))
184                         revs->max_count = 1;
185                 else if (!strcmp(argv[1], "--ours"))
186                         revs->max_count = 2;
187                 else if (!strcmp(argv[1], "--theirs"))
188                         revs->max_count = 3;
189                 else if (!strcmp(argv[1], "-n") ||
190                                 !strcmp(argv[1], "--no-index")) {
191                         revs->max_count = -2;
192                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
193                         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
194                 }
195                 else if (!strcmp(argv[1], "-q"))
196                         *options |= DIFF_SILENT_ON_REMOVED;
197                 else
198                         return error("invalid option: %s", argv[1]);
199                 argv++; argc--;
200         }
201
202         if (revs->max_count == -1 && revs->diffopt.nr_paths == 2) {
203                 /*
204                  * If two files are specified, and at least one is untracked,
205                  * default to no-index.
206                  */
207                 read_cache();
208                 if (!is_in_index(revs->diffopt.paths[0]) ||
209                                         !is_in_index(revs->diffopt.paths[1])) {
210                         revs->max_count = -2;
211                         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
212                 }
213         }
214
215         /*
216          * Make sure there are NO revision (i.e. pending object) parameter,
217          * rev.max_count is reasonable (0 <= n <= 3),
218          * there is no other revision filtering parameters.
219          */
220         if (revs->pending.nr || revs->max_count > 3 ||
221             revs->min_age != -1 || revs->max_age != -1)
222                 return error("no revision allowed with diff-files");
223
224         if (revs->max_count == -1 &&
225             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
226                 revs->combine_merges = revs->dense_combined_merges = 1;
227
228         return 0;
229 }
230
231 static int is_outside_repo(const char *path, int nongit, const char *prefix)
232 {
233         int i;
234         if (nongit || !strcmp(path, "-") || is_absolute_path(path))
235                 return 1;
236         if (prefixcmp(path, "../"))
237                 return 0;
238         if (!prefix)
239                 return 1;
240         for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
241                 while (i > 0 && prefix[i - 1] != '/')
242                         i--;
243                 if (--i < 0)
244                         return 1;
245                 path += 3;
246         }
247         return 0;
248 }
249
250 int setup_diff_no_index(struct rev_info *revs,
251                 int argc, const char ** argv, int nongit, const char *prefix)
252 {
253         int i;
254         for (i = 1; i < argc; i++)
255                 if (argv[i][0] != '-' || argv[i][1] == '\0')
256                         break;
257                 else if (!strcmp(argv[i], "--")) {
258                         i++;
259                         break;
260                 } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
261                         i = argc - 3;
262                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
263                         break;
264                 }
265         if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
266                                 !is_outside_repo(argv[i], nongit, prefix)))
267                 return -1;
268
269         diff_setup(&revs->diffopt);
270         for (i = 1; i < argc - 2; )
271                 if (!strcmp(argv[i], "--no-index"))
272                         i++;
273                 else {
274                         int j = diff_opt_parse(&revs->diffopt,
275                                         argv + i, argc - i);
276                         if (!j)
277                                 die("invalid diff option/value: %s", argv[i]);
278                         i += j;
279                 }
280
281         if (prefix) {
282                 int len = strlen(prefix);
283
284                 revs->diffopt.paths = xcalloc(2, sizeof(char*));
285                 for (i = 0; i < 2; i++) {
286                         const char *p = argv[argc - 2 + i];
287                         /*
288                          * stdin should be spelled as '-'; if you have
289                          * path that is '-', spell it as ./-.
290                          */
291                         p = (strcmp(p, "-")
292                              ? xstrdup(prefix_filename(prefix, len, p))
293                              : p);
294                         revs->diffopt.paths[i] = p;
295                 }
296         }
297         else
298                 revs->diffopt.paths = argv + argc - 2;
299         revs->diffopt.nr_paths = 2;
300         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
301         revs->max_count = -2;
302         if (diff_setup_done(&revs->diffopt) < 0)
303                 die("diff_setup_done failed");
304         return 0;
305 }
306
307 int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
308 {
309         unsigned int options;
310
311         if (handle_diff_files_args(revs, argc, argv, &options))
312                 return -1;
313
314         if (DIFF_OPT_TST(&revs->diffopt, NO_INDEX)) {
315                 if (revs->diffopt.nr_paths != 2)
316                         return error("need two files/directories with --no-index");
317                 if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
318                                 revs->diffopt.paths[1]))
319                         return -1;
320                 diffcore_std(&revs->diffopt);
321                 diff_flush(&revs->diffopt);
322                 /*
323                  * The return code for --no-index imitates diff(1):
324                  * 0 = no changes, 1 = changes, else error
325                  */
326                 return revs->diffopt.found_changes;
327         }
328
329         if (read_cache() < 0) {
330                 perror("read_cache");
331                 return -1;
332         }
333         return run_diff_files(revs, options);
334 }
335
336 int run_diff_files(struct rev_info *revs, unsigned int option)
337 {
338         int entries, i;
339         int diff_unmerged_stage = revs->max_count;
340         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
341         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
342                               ? CE_MATCH_RACY_IS_DIRTY : 0);
343
344         if (diff_unmerged_stage < 0)
345                 diff_unmerged_stage = 2;
346         entries = active_nr;
347         for (i = 0; i < entries; i++) {
348                 struct stat st;
349                 unsigned int oldmode, newmode;
350                 struct cache_entry *ce = active_cache[i];
351                 int changed;
352
353                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
354                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
355                         break;
356
357                 if (!ce_path_match(ce, revs->prune_data))
358                         continue;
359
360                 if (ce_stage(ce)) {
361                         struct combine_diff_path *dpath;
362                         int num_compare_stages = 0;
363                         size_t path_len;
364
365                         path_len = ce_namelen(ce);
366
367                         dpath = xmalloc(combine_diff_path_size(5, path_len));
368                         dpath->path = (char *) &(dpath->parent[5]);
369
370                         dpath->next = NULL;
371                         dpath->len = path_len;
372                         memcpy(dpath->path, ce->name, path_len);
373                         dpath->path[path_len] = '\0';
374                         hashclr(dpath->sha1);
375                         memset(&(dpath->parent[0]), 0,
376                                sizeof(struct combine_diff_parent)*5);
377
378                         if (lstat(ce->name, &st) < 0) {
379                                 if (errno != ENOENT && errno != ENOTDIR) {
380                                         perror(ce->name);
381                                         continue;
382                                 }
383                                 if (silent_on_removed)
384                                         continue;
385                         }
386                         else
387                                 dpath->mode = ntohl(ce_mode_from_stat(ce, st.st_mode));
388
389                         while (i < entries) {
390                                 struct cache_entry *nce = active_cache[i];
391                                 int stage;
392
393                                 if (strcmp(ce->name, nce->name))
394                                         break;
395
396                                 /* Stage #2 (ours) is the first parent,
397                                  * stage #3 (theirs) is the second.
398                                  */
399                                 stage = ce_stage(nce);
400                                 if (2 <= stage) {
401                                         int mode = ntohl(nce->ce_mode);
402                                         num_compare_stages++;
403                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
404                                         dpath->parent[stage-2].mode = ntohl(ce_mode_from_stat(nce, mode));
405                                         dpath->parent[stage-2].status =
406                                                 DIFF_STATUS_MODIFIED;
407                                 }
408
409                                 /* diff against the proper unmerged stage */
410                                 if (stage == diff_unmerged_stage)
411                                         ce = nce;
412                                 i++;
413                         }
414                         /*
415                          * Compensate for loop update
416                          */
417                         i--;
418
419                         if (revs->combine_merges && num_compare_stages == 2) {
420                                 show_combined_diff(dpath, 2,
421                                                    revs->dense_combined_merges,
422                                                    revs);
423                                 free(dpath);
424                                 continue;
425                         }
426                         free(dpath);
427                         dpath = NULL;
428
429                         /*
430                          * Show the diff for the 'ce' if we found the one
431                          * from the desired stage.
432                          */
433                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
434                         if (ce_stage(ce) != diff_unmerged_stage)
435                                 continue;
436                 }
437
438                 if (lstat(ce->name, &st) < 0) {
439                         if (errno != ENOENT && errno != ENOTDIR) {
440                                 perror(ce->name);
441                                 continue;
442                         }
443                         if (silent_on_removed)
444                                 continue;
445                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
446                                        ce->sha1, ce->name, NULL);
447                         continue;
448                 }
449                 changed = ce_match_stat(ce, &st, ce_option);
450                 if (!changed && !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
451                         continue;
452                 oldmode = ntohl(ce->ce_mode);
453                 newmode = ntohl(ce_mode_from_stat(ce, st.st_mode));
454                 diff_change(&revs->diffopt, oldmode, newmode,
455                             ce->sha1, (changed ? null_sha1 : ce->sha1),
456                             ce->name, NULL);
457
458         }
459         diffcore_std(&revs->diffopt);
460         diff_flush(&revs->diffopt);
461         return 0;
462 }
463
464 /*
465  * diff-index
466  */
467
468 /* A file entry went away or appeared */
469 static void diff_index_show_file(struct rev_info *revs,
470                                  const char *prefix,
471                                  struct cache_entry *ce,
472                                  unsigned char *sha1, unsigned int mode)
473 {
474         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
475                        sha1, ce->name, NULL);
476 }
477
478 static int get_stat_data(struct cache_entry *ce,
479                          unsigned char **sha1p,
480                          unsigned int *modep,
481                          int cached, int match_missing)
482 {
483         unsigned char *sha1 = ce->sha1;
484         unsigned int mode = ce->ce_mode;
485
486         if (!cached) {
487                 static unsigned char no_sha1[20];
488                 int changed;
489                 struct stat st;
490                 if (lstat(ce->name, &st) < 0) {
491                         if (errno == ENOENT && match_missing) {
492                                 *sha1p = sha1;
493                                 *modep = mode;
494                                 return 0;
495                         }
496                         return -1;
497                 }
498                 changed = ce_match_stat(ce, &st, 0);
499                 if (changed) {
500                         mode = ce_mode_from_stat(ce, st.st_mode);
501                         sha1 = no_sha1;
502                 }
503         }
504
505         *sha1p = sha1;
506         *modep = mode;
507         return 0;
508 }
509
510 static void show_new_file(struct rev_info *revs,
511                           struct cache_entry *new,
512                           int cached, int match_missing)
513 {
514         unsigned char *sha1;
515         unsigned int mode;
516
517         /* New file in the index: it might actually be different in
518          * the working copy.
519          */
520         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
521                 return;
522
523         diff_index_show_file(revs, "+", new, sha1, mode);
524 }
525
526 static int show_modified(struct rev_info *revs,
527                          struct cache_entry *old,
528                          struct cache_entry *new,
529                          int report_missing,
530                          int cached, int match_missing)
531 {
532         unsigned int mode, oldmode;
533         unsigned char *sha1;
534
535         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
536                 if (report_missing)
537                         diff_index_show_file(revs, "-", old,
538                                              old->sha1, old->ce_mode);
539                 return -1;
540         }
541
542         if (revs->combine_merges && !cached &&
543             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
544                 struct combine_diff_path *p;
545                 int pathlen = ce_namelen(new);
546
547                 p = xmalloc(combine_diff_path_size(2, pathlen));
548                 p->path = (char *) &p->parent[2];
549                 p->next = NULL;
550                 p->len = pathlen;
551                 memcpy(p->path, new->name, pathlen);
552                 p->path[pathlen] = 0;
553                 p->mode = ntohl(mode);
554                 hashclr(p->sha1);
555                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
556                 p->parent[0].status = DIFF_STATUS_MODIFIED;
557                 p->parent[0].mode = ntohl(new->ce_mode);
558                 hashcpy(p->parent[0].sha1, new->sha1);
559                 p->parent[1].status = DIFF_STATUS_MODIFIED;
560                 p->parent[1].mode = ntohl(old->ce_mode);
561                 hashcpy(p->parent[1].sha1, old->sha1);
562                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
563                 free(p);
564                 return 0;
565         }
566
567         oldmode = old->ce_mode;
568         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
569             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
570                 return 0;
571
572         mode = ntohl(mode);
573         oldmode = ntohl(oldmode);
574
575         diff_change(&revs->diffopt, oldmode, mode,
576                     old->sha1, sha1, old->name, NULL);
577         return 0;
578 }
579
580 static int diff_cache(struct rev_info *revs,
581                       struct cache_entry **ac, int entries,
582                       const char **pathspec,
583                       int cached, int match_missing)
584 {
585         while (entries) {
586                 struct cache_entry *ce = *ac;
587                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
588
589                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
590                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
591                         break;
592
593                 if (!ce_path_match(ce, pathspec))
594                         goto skip_entry;
595
596                 switch (ce_stage(ce)) {
597                 case 0:
598                         /* No stage 1 entry? That means it's a new file */
599                         if (!same) {
600                                 show_new_file(revs, ce, cached, match_missing);
601                                 break;
602                         }
603                         /* Show difference between old and new */
604                         show_modified(revs, ac[1], ce, 1,
605                                       cached, match_missing);
606                         break;
607                 case 1:
608                         /* No stage 3 (merge) entry?
609                          * That means it's been deleted.
610                          */
611                         if (!same) {
612                                 diff_index_show_file(revs, "-", ce,
613                                                      ce->sha1, ce->ce_mode);
614                                 break;
615                         }
616                         /* We come here with ce pointing at stage 1
617                          * (original tree) and ac[1] pointing at stage
618                          * 3 (unmerged).  show-modified with
619                          * report-missing set to false does not say the
620                          * file is deleted but reports true if work
621                          * tree does not have it, in which case we
622                          * fall through to report the unmerged state.
623                          * Otherwise, we show the differences between
624                          * the original tree and the work tree.
625                          */
626                         if (!cached &&
627                             !show_modified(revs, ce, ac[1], 0,
628                                            cached, match_missing))
629                                 break;
630                         diff_unmerge(&revs->diffopt, ce->name,
631                                      ntohl(ce->ce_mode), ce->sha1);
632                         break;
633                 case 3:
634                         diff_unmerge(&revs->diffopt, ce->name,
635                                      0, null_sha1);
636                         break;
637
638                 default:
639                         die("impossible cache entry stage");
640                 }
641
642 skip_entry:
643                 /*
644                  * Ignore all the different stages for this file,
645                  * we've handled the relevant cases now.
646                  */
647                 do {
648                         ac++;
649                         entries--;
650                 } while (entries && ce_same_name(ce, ac[0]));
651         }
652         return 0;
653 }
654
655 /*
656  * This turns all merge entries into "stage 3". That guarantees that
657  * when we read in the new tree (into "stage 1"), we won't lose sight
658  * of the fact that we had unmerged entries.
659  */
660 static void mark_merge_entries(void)
661 {
662         int i;
663         for (i = 0; i < active_nr; i++) {
664                 struct cache_entry *ce = active_cache[i];
665                 if (!ce_stage(ce))
666                         continue;
667                 ce->ce_flags |= htons(CE_STAGEMASK);
668         }
669 }
670
671 int run_diff_index(struct rev_info *revs, int cached)
672 {
673         int ret;
674         struct object *ent;
675         struct tree *tree;
676         const char *tree_name;
677         int match_missing = 0;
678
679         /*
680          * Backward compatibility wart - "diff-index -m" does
681          * not mean "do not ignore merges", but totally different.
682          */
683         if (!revs->ignore_merges)
684                 match_missing = 1;
685
686         mark_merge_entries();
687
688         ent = revs->pending.objects[0].item;
689         tree_name = revs->pending.objects[0].name;
690         tree = parse_tree_indirect(ent->sha1);
691         if (!tree)
692                 return error("bad tree object %s", tree_name);
693         if (read_tree(tree, 1, revs->prune_data))
694                 return error("unable to read tree object %s", tree_name);
695         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
696                          cached, match_missing);
697         diffcore_std(&revs->diffopt);
698         diff_flush(&revs->diffopt);
699         return ret;
700 }
701
702 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
703 {
704         struct tree *tree;
705         struct rev_info revs;
706         int i;
707         struct cache_entry **dst;
708         struct cache_entry *last = NULL;
709
710         /*
711          * This is used by git-blame to run diff-cache internally;
712          * it potentially needs to repeatedly run this, so we will
713          * start by removing the higher order entries the last round
714          * left behind.
715          */
716         dst = active_cache;
717         for (i = 0; i < active_nr; i++) {
718                 struct cache_entry *ce = active_cache[i];
719                 if (ce_stage(ce)) {
720                         if (last && !strcmp(ce->name, last->name))
721                                 continue;
722                         cache_tree_invalidate_path(active_cache_tree,
723                                                    ce->name);
724                         last = ce;
725                         ce->ce_mode = 0;
726                         ce->ce_flags &= ~htons(CE_STAGEMASK);
727                 }
728                 *dst++ = ce;
729         }
730         active_nr = dst - active_cache;
731
732         init_revisions(&revs, NULL);
733         revs.prune_data = opt->paths;
734         tree = parse_tree_indirect(tree_sha1);
735         if (!tree)
736                 die("bad tree object %s", sha1_to_hex(tree_sha1));
737         if (read_tree(tree, 1, opt->paths))
738                 return error("unable to read tree %s", sha1_to_hex(tree_sha1));
739         return diff_cache(&revs, active_cache, active_nr, revs.prune_data,
740                           1, 0);
741 }