Make GIT-VERSION-GEN tolerate missing git describe command
[git] / show-branch.c
1 #include <stdlib.h>
2 #include <fnmatch.h>
3 #include "cache.h"
4 #include "commit.h"
5 #include "refs.h"
6
7 static const char show_branch_usage[] =
8 "git-show-branch [--all] [--heads] [--tags] [--topo-order] [--more=count | --list | --independent | --merge-base ] [<refs>...]";
9
10 #define UNINTERESTING   01
11
12 #define REV_SHIFT        2
13 #define MAX_REVS        29 /* should not exceed bits_per_int - REV_SHIFT */
14
15 static struct commit *interesting(struct commit_list *list)
16 {
17         while (list) {
18                 struct commit *commit = list->item;
19                 list = list->next;
20                 if (commit->object.flags & UNINTERESTING)
21                         continue;
22                 return commit;
23         }
24         return NULL;
25 }
26
27 static struct commit *pop_one_commit(struct commit_list **list_p)
28 {
29         struct commit *commit;
30         struct commit_list *list;
31         list = *list_p;
32         commit = list->item;
33         *list_p = list->next;
34         free(list);
35         return commit;
36 }
37
38 struct commit_name {
39         const char *head_name; /* which head's ancestor? */
40         int generation; /* how many parents away from head_name */
41 };
42
43 /* Name the commit as nth generation ancestor of head_name;
44  * we count only the first-parent relationship for naming purposes.
45  */
46 static void name_commit(struct commit *commit, const char *head_name, int nth)
47 {
48         struct commit_name *name;
49         if (!commit->object.util)
50                 commit->object.util = xmalloc(sizeof(struct commit_name));
51         name = commit->object.util;
52         name->head_name = head_name;
53         name->generation = nth;
54 }
55
56 /* Parent is the first parent of the commit.  We may name it
57  * as (n+1)th generation ancestor of the same head_name as
58  * commit is nth generation ancestor of, if that generation
59  * number is better than the name it already has.
60  */
61 static void name_parent(struct commit *commit, struct commit *parent)
62 {
63         struct commit_name *commit_name = commit->object.util;
64         struct commit_name *parent_name = parent->object.util;
65         if (!commit_name)
66                 return;
67         if (!parent_name ||
68             commit_name->generation + 1 < parent_name->generation)
69                 name_commit(parent, commit_name->head_name,
70                             commit_name->generation + 1);
71 }
72
73 static int name_first_parent_chain(struct commit *c)
74 {
75         int i = 0;
76         while (c) {
77                 struct commit *p;
78                 if (!c->object.util)
79                         break;
80                 if (!c->parents)
81                         break;
82                 p = c->parents->item;
83                 if (!p->object.util) {
84                         name_parent(c, p);
85                         i++;
86                 }
87                 c = p;
88         }
89         return i;
90 }
91
92 static void name_commits(struct commit_list *list,
93                          struct commit **rev,
94                          char **ref_name,
95                          int num_rev)
96 {
97         struct commit_list *cl;
98         struct commit *c;
99         int i;
100
101         /* First give names to the given heads */
102         for (cl = list; cl; cl = cl->next) {
103                 c = cl->item;
104                 if (c->object.util)
105                         continue;
106                 for (i = 0; i < num_rev; i++) {
107                         if (rev[i] == c) {
108                                 name_commit(c, ref_name[i], 0);
109                                 break;
110                         }
111                 }
112         }
113
114         /* Then commits on the first parent ancestry chain */
115         do {
116                 i = 0;
117                 for (cl = list; cl; cl = cl->next) {
118                         i += name_first_parent_chain(cl->item);
119                 }
120         } while (i);
121
122         /* Finally, any unnamed commits */
123         do {
124                 i = 0;
125                 for (cl = list; cl; cl = cl->next) {
126                         struct commit_list *parents;
127                         struct commit_name *n;
128                         int nth;
129                         c = cl->item;
130                         if (!c->object.util)
131                                 continue;
132                         n = c->object.util;
133                         parents = c->parents;
134                         nth = 0;
135                         while (parents) {
136                                 struct commit *p = parents->item;
137                                 char newname[1000], *en;
138                                 parents = parents->next;
139                                 nth++;
140                                 if (p->object.util)
141                                         continue;
142                                 en = newname;
143                                 switch (n->generation) {
144                                 case 0:
145                                         en += sprintf(en, "%s", n->head_name);
146                                         break;
147                                 case 1:
148                                         en += sprintf(en, "%s^", n->head_name);
149                                         break;
150                                 default:
151                                         en += sprintf(en, "%s~%d",
152                                                 n->head_name, n->generation);
153                                         break;
154                                 }
155                                 if (nth == 1)
156                                         en += sprintf(en, "^");
157                                 else
158                                         en += sprintf(en, "^%d", nth);
159                                 name_commit(p, strdup(newname), 0);
160                                 i++;
161                                 name_first_parent_chain(p);
162                         }
163                 }
164         } while (i);
165 }
166
167 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
168 {
169         if (!commit->object.flags) {
170                 insert_by_date(commit, seen_p);
171                 return 1;
172         }
173         return 0;
174 }
175
176 static void join_revs(struct commit_list **list_p,
177                       struct commit_list **seen_p,
178                       int num_rev, int extra)
179 {
180         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
181         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
182
183         while (*list_p) {
184                 struct commit_list *parents;
185                 int still_interesting = !!interesting(*list_p);
186                 struct commit *commit = pop_one_commit(list_p);
187                 int flags = commit->object.flags & all_mask;
188
189                 if (!still_interesting && extra <= 0)
190                         break;
191
192                 mark_seen(commit, seen_p);
193                 if ((flags & all_revs) == all_revs)
194                         flags |= UNINTERESTING;
195                 parents = commit->parents;
196
197                 while (parents) {
198                         struct commit *p = parents->item;
199                         int this_flag = p->object.flags;
200                         parents = parents->next;
201                         if ((this_flag & flags) == flags)
202                                 continue;
203                         if (!p->object.parsed)
204                                 parse_commit(p);
205                         if (mark_seen(p, seen_p) && !still_interesting)
206                                 extra--;
207                         p->object.flags |= flags;
208                         insert_by_date(p, list_p);
209                 }
210         }
211
212         /*
213          * Postprocess to complete well-poisoning.
214          *
215          * At this point we have all the commits we have seen in
216          * seen_p list (which happens to be sorted chronologically but
217          * it does not really matter).  Mark anything that can be
218          * reached from uninteresting commits not interesting.
219          */
220         for (;;) {
221                 int changed = 0;
222                 struct commit_list *s;
223                 for (s = *seen_p; s; s = s->next) {
224                         struct commit *c = s->item;
225                         struct commit_list *parents;
226
227                         if (((c->object.flags & all_revs) != all_revs) &&
228                             !(c->object.flags & UNINTERESTING))
229                                 continue;
230
231                         /* The current commit is either a merge base or
232                          * already uninteresting one.  Mark its parents
233                          * as uninteresting commits _only_ if they are
234                          * already parsed.  No reason to find new ones
235                          * here.
236                          */
237                         parents = c->parents;
238                         while (parents) {
239                                 struct commit *p = parents->item;
240                                 parents = parents->next;
241                                 if (!(p->object.flags & UNINTERESTING)) {
242                                         p->object.flags |= UNINTERESTING;
243                                         changed = 1;
244                                 }
245                         }
246                 }
247                 if (!changed)
248                         break;
249         }
250 }
251
252 static void show_one_commit(struct commit *commit, int no_name)
253 {
254         char pretty[256], *cp;
255         struct commit_name *name = commit->object.util;
256         if (commit->object.parsed)
257                 pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
258                                     pretty, sizeof(pretty));
259         else
260                 strcpy(pretty, "(unavailable)");
261         if (!strncmp(pretty, "[PATCH] ", 8))
262                 cp = pretty + 8;
263         else
264                 cp = pretty;
265
266         if (!no_name) {
267                 if (name && name->head_name) {
268                         printf("[%s", name->head_name);
269                         if (name->generation) {
270                                 if (name->generation == 1)
271                                         printf("^");
272                                 else
273                                         printf("~%d", name->generation);
274                         }
275                         printf("] ");
276                 }
277                 else
278                         printf("[%s] ",
279                                find_unique_abbrev(commit->object.sha1, 7));
280         }
281         puts(cp);
282 }
283
284 static char *ref_name[MAX_REVS + 1];
285 static int ref_name_cnt;
286
287 static const char *find_digit_prefix(const char *s, int *v)
288 {
289         const char *p;
290         int ver;
291         char ch;
292
293         for (p = s, ver = 0;
294              '0' <= (ch = *p) && ch <= '9';
295              p++)
296                 ver = ver * 10 + ch - '0';
297         *v = ver;
298         return p;
299 }
300
301
302 static int version_cmp(const char *a, const char *b)
303 {
304         while (1) {
305                 int va, vb;
306
307                 a = find_digit_prefix(a, &va);
308                 b = find_digit_prefix(b, &vb);
309                 if (va != vb)
310                         return va - vb;
311
312                 while (1) {
313                         int ca = *a;
314                         int cb = *b;
315                         if ('0' <= ca && ca <= '9')
316                                 ca = 0;
317                         if ('0' <= cb && cb <= '9')
318                                 cb = 0;
319                         if (ca != cb)
320                                 return ca - cb;
321                         if (!ca)
322                                 break;
323                         a++;
324                         b++;
325                 }
326                 if (!*a && !*b)
327                         return 0;
328         }
329 }
330
331 static int compare_ref_name(const void *a_, const void *b_)
332 {
333         const char * const*a = a_, * const*b = b_;
334         return version_cmp(*a, *b);
335 }
336
337 static void sort_ref_range(int bottom, int top)
338 {
339         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
340               compare_ref_name);
341 }
342
343 static int append_ref(const char *refname, const unsigned char *sha1)
344 {
345         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
346         int i;
347
348         if (!commit)
349                 return 0;
350         /* Avoid adding the same thing twice */
351         for (i = 0; i < ref_name_cnt; i++)
352                 if (!strcmp(refname, ref_name[i]))
353                         return 0;
354
355         if (MAX_REVS <= ref_name_cnt) {
356                 fprintf(stderr, "warning: ignoring %s; "
357                         "cannot handle more than %d refs\n",
358                         refname, MAX_REVS);
359                 return 0;
360         }
361         ref_name[ref_name_cnt++] = strdup(refname);
362         ref_name[ref_name_cnt] = NULL;
363         return 0;
364 }
365
366 static int append_head_ref(const char *refname, const unsigned char *sha1)
367 {
368         unsigned char tmp[20];
369         int ofs = 11;
370         if (strncmp(refname, "refs/heads/", ofs))
371                 return 0;
372         /* If both heads/foo and tags/foo exists, get_sha1 would
373          * get confused.
374          */
375         if (get_sha1(refname + ofs, tmp) || memcmp(tmp, sha1, 20))
376                 ofs = 5;
377         return append_ref(refname + ofs, sha1);
378 }
379
380 static int append_tag_ref(const char *refname, const unsigned char *sha1)
381 {
382         if (strncmp(refname, "refs/tags/", 10))
383                 return 0;
384         return append_ref(refname + 5, sha1);
385 }
386
387 static const char *match_ref_pattern = NULL;
388 static int match_ref_slash = 0;
389 static int count_slash(const char *s)
390 {
391         int cnt = 0;
392         while (*s)
393                 if (*s++ == '/')
394                         cnt++;
395         return cnt;
396 }
397
398 static int append_matching_ref(const char *refname, const unsigned char *sha1)
399 {
400         /* we want to allow pattern hold/<asterisk> to show all
401          * branches under refs/heads/hold/, and v0.99.9? to show
402          * refs/tags/v0.99.9a and friends.
403          */
404         const char *tail;
405         int slash = count_slash(refname);
406         for (tail = refname; *tail && match_ref_slash < slash; )
407                 if (*tail++ == '/')
408                         slash--;
409         if (!*tail)
410                 return 0;
411         if (fnmatch(match_ref_pattern, tail, 0))
412                 return 0;
413         if (!strncmp("refs/heads/", refname, 11))
414                 return append_head_ref(refname, sha1);
415         if (!strncmp("refs/tags/", refname, 10))
416                 return append_tag_ref(refname, sha1);
417         return append_ref(refname, sha1);
418 }
419
420 static void snarf_refs(int head, int tag)
421 {
422         if (head) {
423                 int orig_cnt = ref_name_cnt;
424                 for_each_ref(append_head_ref);
425                 sort_ref_range(orig_cnt, ref_name_cnt);
426         }
427         if (tag) {
428                 int orig_cnt = ref_name_cnt;
429                 for_each_ref(append_tag_ref);
430                 sort_ref_range(orig_cnt, ref_name_cnt);
431         }
432 }
433
434 static int rev_is_head(char *head_path, int headlen,
435                        char *name,
436                        unsigned char *head_sha1, unsigned char *sha1)
437 {
438         int namelen;
439         if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
440                 return 0;
441         namelen = strlen(name);
442         if ((headlen < namelen) ||
443             memcmp(head_path + headlen - namelen, name, namelen))
444                 return 0;
445         if (headlen == namelen ||
446             head_path[headlen - namelen - 1] == '/')
447                 return 1;
448         return 0;
449 }
450
451 static int show_merge_base(struct commit_list *seen, int num_rev)
452 {
453         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
454         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
455         int exit_status = 1;
456
457         while (seen) {
458                 struct commit *commit = pop_one_commit(&seen);
459                 int flags = commit->object.flags & all_mask;
460                 if (!(flags & UNINTERESTING) &&
461                     ((flags & all_revs) == all_revs)) {
462                         puts(sha1_to_hex(commit->object.sha1));
463                         exit_status = 0;
464                         commit->object.flags |= UNINTERESTING;
465                 }
466         }
467         return exit_status;
468 }
469
470 static int show_independent(struct commit **rev,
471                             int num_rev,
472                             char **ref_name,
473                             unsigned int *rev_mask)
474 {
475         int i;
476
477         for (i = 0; i < num_rev; i++) {
478                 struct commit *commit = rev[i];
479                 unsigned int flag = rev_mask[i];
480
481                 if (commit->object.flags == flag)
482                         puts(sha1_to_hex(commit->object.sha1));
483                 commit->object.flags |= UNINTERESTING;
484         }
485         return 0;
486 }
487
488 static void append_one_rev(const char *av)
489 {
490         unsigned char revkey[20];
491         if (!get_sha1(av, revkey)) {
492                 append_ref(av, revkey);
493                 return;
494         }
495         if (strchr(av, '*') || strchr(av, '?')) {
496                 /* glob style match */
497                 int saved_matches = ref_name_cnt;
498                 match_ref_pattern = av;
499                 match_ref_slash = count_slash(av);
500                 for_each_ref(append_matching_ref);
501                 if (saved_matches == ref_name_cnt &&
502                     ref_name_cnt < MAX_REVS)
503                         error("no matching refs with %s", av);
504                 if (saved_matches + 1 < ref_name_cnt)
505                         sort_ref_range(saved_matches, ref_name_cnt);
506                 return;
507         }
508         die("bad sha1 reference %s", av);
509 }
510
511 int main(int ac, char **av)
512 {
513         struct commit *rev[MAX_REVS], *commit;
514         struct commit_list *list = NULL, *seen = NULL;
515         unsigned int rev_mask[MAX_REVS];
516         int num_rev, i, extra = 0;
517         int all_heads = 0, all_tags = 0;
518         int all_mask, all_revs;
519         char head_path[128];
520         const char *head_path_p;
521         int head_path_len;
522         unsigned char head_sha1[20];
523         int merge_base = 0;
524         int independent = 0;
525         int no_name = 0;
526         int sha1_name = 0;
527         int shown_merge_point = 0;
528         int topo_order = 0;
529
530         setup_git_directory();
531
532         while (1 < ac && av[1][0] == '-') {
533                 char *arg = av[1];
534                 if (!strcmp(arg, "--all"))
535                         all_heads = all_tags = 1;
536                 else if (!strcmp(arg, "--heads"))
537                         all_heads = 1;
538                 else if (!strcmp(arg, "--tags"))
539                         all_tags = 1;
540                 else if (!strcmp(arg, "--more"))
541                         extra = 1;
542                 else if (!strcmp(arg, "--list"))
543                         extra = -1;
544                 else if (!strcmp(arg, "--no-name"))
545                         no_name = 1;
546                 else if (!strcmp(arg, "--sha1-name"))
547                         sha1_name = 1;
548                 else if (!strncmp(arg, "--more=", 7))
549                         extra = atoi(arg + 7);
550                 else if (!strcmp(arg, "--merge-base"))
551                         merge_base = 1;
552                 else if (!strcmp(arg, "--independent"))
553                         independent = 1;
554                 else if (!strcmp(arg, "--topo-order"))
555                         topo_order = 1;
556                 else
557                         usage(show_branch_usage);
558                 ac--; av++;
559         }
560         ac--; av++;
561
562         /* Only one of these is allowed */
563         if (1 < independent + merge_base + (extra != 0))
564                 usage(show_branch_usage);
565
566         /* If nothing is specified, show all branches by default */
567         if (ac + all_heads + all_tags == 0)
568                 all_heads = 1;
569
570         if (all_heads + all_tags)
571                 snarf_refs(all_heads, all_tags);
572         while (0 < ac) {
573                 append_one_rev(*av);
574                 ac--; av++;
575         }
576
577         if (!ref_name_cnt) {
578                 fprintf(stderr, "No revs to be shown.\n");
579                 exit(0);
580         }
581
582         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
583                 unsigned char revkey[20];
584                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
585
586                 if (MAX_REVS <= num_rev)
587                         die("cannot handle more than %d revs.", MAX_REVS);
588                 if (get_sha1(ref_name[num_rev], revkey))
589                         die("'%s' is not a valid ref.", ref_name[num_rev]);
590                 commit = lookup_commit_reference(revkey);
591                 if (!commit)
592                         die("cannot find commit %s (%s)",
593                             ref_name[num_rev], revkey);
594                 parse_commit(commit);
595                 mark_seen(commit, &seen);
596
597                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
598                  * and so on.  REV_SHIFT bits from bit 0 are used for
599                  * internal bookkeeping.
600                  */
601                 commit->object.flags |= flag;
602                 if (commit->object.flags == flag)
603                         insert_by_date(commit, &list);
604                 rev[num_rev] = commit;
605         }
606         for (i = 0; i < num_rev; i++)
607                 rev_mask[i] = rev[i]->object.flags;
608
609         if (0 <= extra)
610                 join_revs(&list, &seen, num_rev, extra);
611
612         head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1);
613         if (head_path_p) {
614                 head_path_len = strlen(head_path_p);
615                 memcpy(head_path, head_path_p, head_path_len + 1);
616         }
617         else {
618                 head_path_len = 0;
619                 head_path[0] = 0;
620         }
621
622         if (merge_base)
623                 return show_merge_base(seen, num_rev);
624
625         if (independent)
626                 return show_independent(rev, num_rev, ref_name, rev_mask);
627
628         /* Show list; --more=-1 means list-only */
629         if (1 < num_rev || extra < 0) {
630                 for (i = 0; i < num_rev; i++) {
631                         int j;
632                         int is_head = rev_is_head(head_path,
633                                                   head_path_len,
634                                                   ref_name[i],
635                                                   head_sha1,
636                                                   rev[i]->object.sha1);
637                         if (extra < 0)
638                                 printf("%c [%s] ",
639                                        is_head ? '*' : ' ', ref_name[i]);
640                         else {
641                                 for (j = 0; j < i; j++)
642                                         putchar(' ');
643                                 printf("%c [%s] ",
644                                        is_head ? '*' : '!', ref_name[i]);
645                         }
646                         /* header lines never need name */
647                         show_one_commit(rev[i], 1);
648                 }
649                 if (0 <= extra) {
650                         for (i = 0; i < num_rev; i++)
651                                 putchar('-');
652                         putchar('\n');
653                 }
654         }
655         if (extra < 0)
656                 exit(0);
657
658         /* Sort topologically */
659         if (topo_order)
660                 sort_in_topological_order(&seen);
661
662         /* Give names to commits */
663         if (!sha1_name && !no_name)
664                 name_commits(seen, rev, ref_name, num_rev);
665
666         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
667         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
668
669         while (seen) {
670                 struct commit *commit = pop_one_commit(&seen);
671                 int this_flag = commit->object.flags;
672
673                 shown_merge_point |= ((this_flag & all_revs) == all_revs);
674
675                 if (1 < num_rev) {
676                         for (i = 0; i < num_rev; i++)
677                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
678                                         ? '+' : ' ');
679                         putchar(' ');
680                 }
681                 show_one_commit(commit, no_name);
682
683                 if (shown_merge_point && --extra < 0)
684                         break;
685         }
686         return 0;
687 }