Documentation: fix git-clone manpage not to refer to itself
[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 (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                         revs->diffopt.exit_with_status = 1;
193                         revs->diffopt.no_index = 1;
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                         revs->diffopt.no_index = 1;
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, "-") || path[0] == '/')
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                         revs->diffopt.exit_with_status = 1;
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         revs->diffopt.no_index = 1;
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 (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 (revs->diffopt.quiet && revs->diffopt.has_changes)
354                         break;
355
356                 if (!ce_path_match(ce, revs->prune_data))
357                         continue;
358
359                 if (ce_stage(ce)) {
360                         struct combine_diff_path *dpath;
361                         int num_compare_stages = 0;
362                         size_t path_len;
363
364                         path_len = ce_namelen(ce);
365
366                         dpath = xmalloc(combine_diff_path_size(5, path_len));
367                         dpath->path = (char *) &(dpath->parent[5]);
368
369                         dpath->next = NULL;
370                         dpath->len = path_len;
371                         memcpy(dpath->path, ce->name, path_len);
372                         dpath->path[path_len] = '\0';
373                         hashclr(dpath->sha1);
374                         memset(&(dpath->parent[0]), 0,
375                                sizeof(struct combine_diff_parent)*5);
376
377                         if (lstat(ce->name, &st) < 0) {
378                                 if (errno != ENOENT && errno != ENOTDIR) {
379                                         perror(ce->name);
380                                         continue;
381                                 }
382                                 if (silent_on_removed)
383                                         continue;
384                         }
385                         else
386                                 dpath->mode = ntohl(ce_mode_from_stat(ce, st.st_mode));
387
388                         while (i < entries) {
389                                 struct cache_entry *nce = active_cache[i];
390                                 int stage;
391
392                                 if (strcmp(ce->name, nce->name))
393                                         break;
394
395                                 /* Stage #2 (ours) is the first parent,
396                                  * stage #3 (theirs) is the second.
397                                  */
398                                 stage = ce_stage(nce);
399                                 if (2 <= stage) {
400                                         int mode = ntohl(nce->ce_mode);
401                                         num_compare_stages++;
402                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
403                                         dpath->parent[stage-2].mode = ntohl(ce_mode_from_stat(nce, mode));
404                                         dpath->parent[stage-2].status =
405                                                 DIFF_STATUS_MODIFIED;
406                                 }
407
408                                 /* diff against the proper unmerged stage */
409                                 if (stage == diff_unmerged_stage)
410                                         ce = nce;
411                                 i++;
412                         }
413                         /*
414                          * Compensate for loop update
415                          */
416                         i--;
417
418                         if (revs->combine_merges && num_compare_stages == 2) {
419                                 show_combined_diff(dpath, 2,
420                                                    revs->dense_combined_merges,
421                                                    revs);
422                                 free(dpath);
423                                 continue;
424                         }
425                         free(dpath);
426                         dpath = NULL;
427
428                         /*
429                          * Show the diff for the 'ce' if we found the one
430                          * from the desired stage.
431                          */
432                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
433                         if (ce_stage(ce) != diff_unmerged_stage)
434                                 continue;
435                 }
436
437                 if (lstat(ce->name, &st) < 0) {
438                         if (errno != ENOENT && errno != ENOTDIR) {
439                                 perror(ce->name);
440                                 continue;
441                         }
442                         if (silent_on_removed)
443                                 continue;
444                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
445                                        ce->sha1, ce->name, NULL);
446                         continue;
447                 }
448                 changed = ce_match_stat(ce, &st, ce_option);
449                 if (!changed && !revs->diffopt.find_copies_harder)
450                         continue;
451                 oldmode = ntohl(ce->ce_mode);
452                 newmode = ntohl(ce_mode_from_stat(ce, st.st_mode));
453                 diff_change(&revs->diffopt, oldmode, newmode,
454                             ce->sha1, (changed ? null_sha1 : ce->sha1),
455                             ce->name, NULL);
456
457         }
458         diffcore_std(&revs->diffopt);
459         diff_flush(&revs->diffopt);
460         return 0;
461 }
462
463 /*
464  * diff-index
465  */
466
467 /* A file entry went away or appeared */
468 static void diff_index_show_file(struct rev_info *revs,
469                                  const char *prefix,
470                                  struct cache_entry *ce,
471                                  unsigned char *sha1, unsigned int mode)
472 {
473         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
474                        sha1, ce->name, NULL);
475 }
476
477 static int get_stat_data(struct cache_entry *ce,
478                          unsigned char **sha1p,
479                          unsigned int *modep,
480                          int cached, int match_missing)
481 {
482         unsigned char *sha1 = ce->sha1;
483         unsigned int mode = ce->ce_mode;
484
485         if (!cached) {
486                 static unsigned char no_sha1[20];
487                 int changed;
488                 struct stat st;
489                 if (lstat(ce->name, &st) < 0) {
490                         if (errno == ENOENT && match_missing) {
491                                 *sha1p = sha1;
492                                 *modep = mode;
493                                 return 0;
494                         }
495                         return -1;
496                 }
497                 changed = ce_match_stat(ce, &st, 0);
498                 if (changed) {
499                         mode = ce_mode_from_stat(ce, st.st_mode);
500                         sha1 = no_sha1;
501                 }
502         }
503
504         *sha1p = sha1;
505         *modep = mode;
506         return 0;
507 }
508
509 static void show_new_file(struct rev_info *revs,
510                           struct cache_entry *new,
511                           int cached, int match_missing)
512 {
513         unsigned char *sha1;
514         unsigned int mode;
515
516         /* New file in the index: it might actually be different in
517          * the working copy.
518          */
519         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
520                 return;
521
522         diff_index_show_file(revs, "+", new, sha1, mode);
523 }
524
525 static int show_modified(struct rev_info *revs,
526                          struct cache_entry *old,
527                          struct cache_entry *new,
528                          int report_missing,
529                          int cached, int match_missing)
530 {
531         unsigned int mode, oldmode;
532         unsigned char *sha1;
533
534         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
535                 if (report_missing)
536                         diff_index_show_file(revs, "-", old,
537                                              old->sha1, old->ce_mode);
538                 return -1;
539         }
540
541         if (revs->combine_merges && !cached &&
542             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
543                 struct combine_diff_path *p;
544                 int pathlen = ce_namelen(new);
545
546                 p = xmalloc(combine_diff_path_size(2, pathlen));
547                 p->path = (char *) &p->parent[2];
548                 p->next = NULL;
549                 p->len = pathlen;
550                 memcpy(p->path, new->name, pathlen);
551                 p->path[pathlen] = 0;
552                 p->mode = ntohl(mode);
553                 hashclr(p->sha1);
554                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
555                 p->parent[0].status = DIFF_STATUS_MODIFIED;
556                 p->parent[0].mode = ntohl(new->ce_mode);
557                 hashcpy(p->parent[0].sha1, new->sha1);
558                 p->parent[1].status = DIFF_STATUS_MODIFIED;
559                 p->parent[1].mode = ntohl(old->ce_mode);
560                 hashcpy(p->parent[1].sha1, old->sha1);
561                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
562                 free(p);
563                 return 0;
564         }
565
566         oldmode = old->ce_mode;
567         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
568             !revs->diffopt.find_copies_harder)
569                 return 0;
570
571         mode = ntohl(mode);
572         oldmode = ntohl(oldmode);
573
574         diff_change(&revs->diffopt, oldmode, mode,
575                     old->sha1, sha1, old->name, NULL);
576         return 0;
577 }
578
579 static int diff_cache(struct rev_info *revs,
580                       struct cache_entry **ac, int entries,
581                       const char **pathspec,
582                       int cached, int match_missing)
583 {
584         while (entries) {
585                 struct cache_entry *ce = *ac;
586                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
587
588                 if (revs->diffopt.quiet && revs->diffopt.has_changes)
589                         break;
590
591                 if (!ce_path_match(ce, pathspec))
592                         goto skip_entry;
593
594                 switch (ce_stage(ce)) {
595                 case 0:
596                         /* No stage 1 entry? That means it's a new file */
597                         if (!same) {
598                                 show_new_file(revs, ce, cached, match_missing);
599                                 break;
600                         }
601                         /* Show difference between old and new */
602                         show_modified(revs, ac[1], ce, 1,
603                                       cached, match_missing);
604                         break;
605                 case 1:
606                         /* No stage 3 (merge) entry?
607                          * That means it's been deleted.
608                          */
609                         if (!same) {
610                                 diff_index_show_file(revs, "-", ce,
611                                                      ce->sha1, ce->ce_mode);
612                                 break;
613                         }
614                         /* We come here with ce pointing at stage 1
615                          * (original tree) and ac[1] pointing at stage
616                          * 3 (unmerged).  show-modified with
617                          * report-missing set to false does not say the
618                          * file is deleted but reports true if work
619                          * tree does not have it, in which case we
620                          * fall through to report the unmerged state.
621                          * Otherwise, we show the differences between
622                          * the original tree and the work tree.
623                          */
624                         if (!cached &&
625                             !show_modified(revs, ce, ac[1], 0,
626                                            cached, match_missing))
627                                 break;
628                         diff_unmerge(&revs->diffopt, ce->name,
629                                      ntohl(ce->ce_mode), ce->sha1);
630                         break;
631                 case 3:
632                         diff_unmerge(&revs->diffopt, ce->name,
633                                      0, null_sha1);
634                         break;
635
636                 default:
637                         die("impossible cache entry stage");
638                 }
639
640 skip_entry:
641                 /*
642                  * Ignore all the different stages for this file,
643                  * we've handled the relevant cases now.
644                  */
645                 do {
646                         ac++;
647                         entries--;
648                 } while (entries && ce_same_name(ce, ac[0]));
649         }
650         return 0;
651 }
652
653 /*
654  * This turns all merge entries into "stage 3". That guarantees that
655  * when we read in the new tree (into "stage 1"), we won't lose sight
656  * of the fact that we had unmerged entries.
657  */
658 static void mark_merge_entries(void)
659 {
660         int i;
661         for (i = 0; i < active_nr; i++) {
662                 struct cache_entry *ce = active_cache[i];
663                 if (!ce_stage(ce))
664                         continue;
665                 ce->ce_flags |= htons(CE_STAGEMASK);
666         }
667 }
668
669 int run_diff_index(struct rev_info *revs, int cached)
670 {
671         int ret;
672         struct object *ent;
673         struct tree *tree;
674         const char *tree_name;
675         int match_missing = 0;
676
677         /*
678          * Backward compatibility wart - "diff-index -m" does
679          * not mean "do not ignore merges", but totally different.
680          */
681         if (!revs->ignore_merges)
682                 match_missing = 1;
683
684         mark_merge_entries();
685
686         ent = revs->pending.objects[0].item;
687         tree_name = revs->pending.objects[0].name;
688         tree = parse_tree_indirect(ent->sha1);
689         if (!tree)
690                 return error("bad tree object %s", tree_name);
691         if (read_tree(tree, 1, revs->prune_data))
692                 return error("unable to read tree object %s", tree_name);
693         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
694                          cached, match_missing);
695         diffcore_std(&revs->diffopt);
696         diff_flush(&revs->diffopt);
697         return ret;
698 }
699
700 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
701 {
702         struct tree *tree;
703         struct rev_info revs;
704         int i;
705         struct cache_entry **dst;
706         struct cache_entry *last = NULL;
707
708         /*
709          * This is used by git-blame to run diff-cache internally;
710          * it potentially needs to repeatedly run this, so we will
711          * start by removing the higher order entries the last round
712          * left behind.
713          */
714         dst = active_cache;
715         for (i = 0; i < active_nr; i++) {
716                 struct cache_entry *ce = active_cache[i];
717                 if (ce_stage(ce)) {
718                         if (last && !strcmp(ce->name, last->name))
719                                 continue;
720                         cache_tree_invalidate_path(active_cache_tree,
721                                                    ce->name);
722                         last = ce;
723                         ce->ce_mode = 0;
724                         ce->ce_flags &= ~htons(CE_STAGEMASK);
725                 }
726                 *dst++ = ce;
727         }
728         active_nr = dst - active_cache;
729
730         init_revisions(&revs, NULL);
731         revs.prune_data = opt->paths;
732         tree = parse_tree_indirect(tree_sha1);
733         if (!tree)
734                 die("bad tree object %s", sha1_to_hex(tree_sha1));
735         if (read_tree(tree, 1, opt->paths))
736                 return error("unable to read tree %s", sha1_to_hex(tree_sha1));
737         return diff_cache(&revs, active_cache, active_nr, revs.prune_data,
738                           1, 0);
739 }