user-manual: update references discussion
[git/libgit-gsoc.git] / builtin-show-branch.c
blobc67f2fa2fe2203b5308eb156d502b75ce44751d5
1 #include "cache.h"
2 #include "commit.h"
3 #include "refs.h"
4 #include "builtin.h"
6 static const char show_branch_usage[] =
7 "git-show-branch [--sparse] [--current] [--all] [--remotes] [--topo-order] [--more=count | --list | --independent | --merge-base ] [--topics] [<refs>...] | --reflog[=n] <branch>";
9 static int default_num;
10 static int default_alloc;
11 static const char **default_arg;
13 #define UNINTERESTING 01
15 #define REV_SHIFT 2
16 #define MAX_REVS (FLAG_BITS - REV_SHIFT) /* should not exceed bits_per_int - REV_SHIFT */
18 #define DEFAULT_REFLOG 4
20 static struct commit *interesting(struct commit_list *list)
22 while (list) {
23 struct commit *commit = list->item;
24 list = list->next;
25 if (commit->object.flags & UNINTERESTING)
26 continue;
27 return commit;
29 return NULL;
32 static struct commit *pop_one_commit(struct commit_list **list_p)
34 struct commit *commit;
35 struct commit_list *list;
36 list = *list_p;
37 commit = list->item;
38 *list_p = list->next;
39 free(list);
40 return commit;
43 struct commit_name {
44 const char *head_name; /* which head's ancestor? */
45 int generation; /* how many parents away from head_name */
48 /* Name the commit as nth generation ancestor of head_name;
49 * we count only the first-parent relationship for naming purposes.
51 static void name_commit(struct commit *commit, const char *head_name, int nth)
53 struct commit_name *name;
54 if (!commit->util)
55 commit->util = xmalloc(sizeof(struct commit_name));
56 name = commit->util;
57 name->head_name = head_name;
58 name->generation = nth;
61 /* Parent is the first parent of the commit. We may name it
62 * as (n+1)th generation ancestor of the same head_name as
63 * commit is nth generation ancestor of, if that generation
64 * number is better than the name it already has.
66 static void name_parent(struct commit *commit, struct commit *parent)
68 struct commit_name *commit_name = commit->util;
69 struct commit_name *parent_name = parent->util;
70 if (!commit_name)
71 return;
72 if (!parent_name ||
73 commit_name->generation + 1 < parent_name->generation)
74 name_commit(parent, commit_name->head_name,
75 commit_name->generation + 1);
78 static int name_first_parent_chain(struct commit *c)
80 int i = 0;
81 while (c) {
82 struct commit *p;
83 if (!c->util)
84 break;
85 if (!c->parents)
86 break;
87 p = c->parents->item;
88 if (!p->util) {
89 name_parent(c, p);
90 i++;
92 else
93 break;
94 c = p;
96 return i;
99 static void name_commits(struct commit_list *list,
100 struct commit **rev,
101 char **ref_name,
102 int num_rev)
104 struct commit_list *cl;
105 struct commit *c;
106 int i;
108 /* First give names to the given heads */
109 for (cl = list; cl; cl = cl->next) {
110 c = cl->item;
111 if (c->util)
112 continue;
113 for (i = 0; i < num_rev; i++) {
114 if (rev[i] == c) {
115 name_commit(c, ref_name[i], 0);
116 break;
121 /* Then commits on the first parent ancestry chain */
122 do {
123 i = 0;
124 for (cl = list; cl; cl = cl->next) {
125 i += name_first_parent_chain(cl->item);
127 } while (i);
129 /* Finally, any unnamed commits */
130 do {
131 i = 0;
132 for (cl = list; cl; cl = cl->next) {
133 struct commit_list *parents;
134 struct commit_name *n;
135 int nth;
136 c = cl->item;
137 if (!c->util)
138 continue;
139 n = c->util;
140 parents = c->parents;
141 nth = 0;
142 while (parents) {
143 struct commit *p = parents->item;
144 char newname[1000], *en;
145 parents = parents->next;
146 nth++;
147 if (p->util)
148 continue;
149 en = newname;
150 switch (n->generation) {
151 case 0:
152 en += sprintf(en, "%s", n->head_name);
153 break;
154 case 1:
155 en += sprintf(en, "%s^", n->head_name);
156 break;
157 default:
158 en += sprintf(en, "%s~%d",
159 n->head_name, n->generation);
160 break;
162 if (nth == 1)
163 en += sprintf(en, "^");
164 else
165 en += sprintf(en, "^%d", nth);
166 name_commit(p, xstrdup(newname), 0);
167 i++;
168 name_first_parent_chain(p);
171 } while (i);
174 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
176 if (!commit->object.flags) {
177 commit_list_insert(commit, seen_p);
178 return 1;
180 return 0;
183 static void join_revs(struct commit_list **list_p,
184 struct commit_list **seen_p,
185 int num_rev, int extra)
187 int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
188 int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
190 while (*list_p) {
191 struct commit_list *parents;
192 int still_interesting = !!interesting(*list_p);
193 struct commit *commit = pop_one_commit(list_p);
194 int flags = commit->object.flags & all_mask;
196 if (!still_interesting && extra <= 0)
197 break;
199 mark_seen(commit, seen_p);
200 if ((flags & all_revs) == all_revs)
201 flags |= UNINTERESTING;
202 parents = commit->parents;
204 while (parents) {
205 struct commit *p = parents->item;
206 int this_flag = p->object.flags;
207 parents = parents->next;
208 if ((this_flag & flags) == flags)
209 continue;
210 if (!p->object.parsed)
211 parse_commit(p);
212 if (mark_seen(p, seen_p) && !still_interesting)
213 extra--;
214 p->object.flags |= flags;
215 insert_by_date(p, list_p);
220 * Postprocess to complete well-poisoning.
222 * At this point we have all the commits we have seen in
223 * seen_p list. Mark anything that can be reached from
224 * uninteresting commits not interesting.
226 for (;;) {
227 int changed = 0;
228 struct commit_list *s;
229 for (s = *seen_p; s; s = s->next) {
230 struct commit *c = s->item;
231 struct commit_list *parents;
233 if (((c->object.flags & all_revs) != all_revs) &&
234 !(c->object.flags & UNINTERESTING))
235 continue;
237 /* The current commit is either a merge base or
238 * already uninteresting one. Mark its parents
239 * as uninteresting commits _only_ if they are
240 * already parsed. No reason to find new ones
241 * here.
243 parents = c->parents;
244 while (parents) {
245 struct commit *p = parents->item;
246 parents = parents->next;
247 if (!(p->object.flags & UNINTERESTING)) {
248 p->object.flags |= UNINTERESTING;
249 changed = 1;
253 if (!changed)
254 break;
258 static void show_one_commit(struct commit *commit, int no_name)
260 char pretty[256], *cp;
261 struct commit_name *name = commit->util;
262 if (commit->object.parsed)
263 pretty_print_commit(CMIT_FMT_ONELINE, commit, ~0,
264 pretty, sizeof(pretty), 0, NULL, NULL, 0);
265 else
266 strcpy(pretty, "(unavailable)");
267 if (!strncmp(pretty, "[PATCH] ", 8))
268 cp = pretty + 8;
269 else
270 cp = pretty;
272 if (!no_name) {
273 if (name && name->head_name) {
274 printf("[%s", name->head_name);
275 if (name->generation) {
276 if (name->generation == 1)
277 printf("^");
278 else
279 printf("~%d", name->generation);
281 printf("] ");
283 else
284 printf("[%s] ",
285 find_unique_abbrev(commit->object.sha1, 7));
287 puts(cp);
290 static char *ref_name[MAX_REVS + 1];
291 static int ref_name_cnt;
293 static const char *find_digit_prefix(const char *s, int *v)
295 const char *p;
296 int ver;
297 char ch;
299 for (p = s, ver = 0;
300 '0' <= (ch = *p) && ch <= '9';
301 p++)
302 ver = ver * 10 + ch - '0';
303 *v = ver;
304 return p;
308 static int version_cmp(const char *a, const char *b)
310 while (1) {
311 int va, vb;
313 a = find_digit_prefix(a, &va);
314 b = find_digit_prefix(b, &vb);
315 if (va != vb)
316 return va - vb;
318 while (1) {
319 int ca = *a;
320 int cb = *b;
321 if ('0' <= ca && ca <= '9')
322 ca = 0;
323 if ('0' <= cb && cb <= '9')
324 cb = 0;
325 if (ca != cb)
326 return ca - cb;
327 if (!ca)
328 break;
329 a++;
330 b++;
332 if (!*a && !*b)
333 return 0;
337 static int compare_ref_name(const void *a_, const void *b_)
339 const char * const*a = a_, * const*b = b_;
340 return version_cmp(*a, *b);
343 static void sort_ref_range(int bottom, int top)
345 qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
346 compare_ref_name);
349 static int append_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
351 struct commit *commit = lookup_commit_reference_gently(sha1, 1);
352 int i;
354 if (!commit)
355 return 0;
356 /* Avoid adding the same thing twice */
357 for (i = 0; i < ref_name_cnt; i++)
358 if (!strcmp(refname, ref_name[i]))
359 return 0;
361 if (MAX_REVS <= ref_name_cnt) {
362 fprintf(stderr, "warning: ignoring %s; "
363 "cannot handle more than %d refs\n",
364 refname, MAX_REVS);
365 return 0;
367 ref_name[ref_name_cnt++] = xstrdup(refname);
368 ref_name[ref_name_cnt] = NULL;
369 return 0;
372 static int append_head_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
374 unsigned char tmp[20];
375 int ofs = 11;
376 if (strncmp(refname, "refs/heads/", ofs))
377 return 0;
378 /* If both heads/foo and tags/foo exists, get_sha1 would
379 * get confused.
381 if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
382 ofs = 5;
383 return append_ref(refname + ofs, sha1, flag, cb_data);
386 static int append_remote_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
388 unsigned char tmp[20];
389 int ofs = 13;
390 if (strncmp(refname, "refs/remotes/", ofs))
391 return 0;
392 /* If both heads/foo and tags/foo exists, get_sha1 would
393 * get confused.
395 if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
396 ofs = 5;
397 return append_ref(refname + ofs, sha1, flag, cb_data);
400 static int append_tag_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
402 if (strncmp(refname, "refs/tags/", 10))
403 return 0;
404 return append_ref(refname + 5, sha1, flag, cb_data);
407 static const char *match_ref_pattern = NULL;
408 static int match_ref_slash = 0;
409 static int count_slash(const char *s)
411 int cnt = 0;
412 while (*s)
413 if (*s++ == '/')
414 cnt++;
415 return cnt;
418 static int append_matching_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
420 /* we want to allow pattern hold/<asterisk> to show all
421 * branches under refs/heads/hold/, and v0.99.9? to show
422 * refs/tags/v0.99.9a and friends.
424 const char *tail;
425 int slash = count_slash(refname);
426 for (tail = refname; *tail && match_ref_slash < slash; )
427 if (*tail++ == '/')
428 slash--;
429 if (!*tail)
430 return 0;
431 if (fnmatch(match_ref_pattern, tail, 0))
432 return 0;
433 if (!strncmp("refs/heads/", refname, 11))
434 return append_head_ref(refname, sha1, flag, cb_data);
435 if (!strncmp("refs/tags/", refname, 10))
436 return append_tag_ref(refname, sha1, flag, cb_data);
437 return append_ref(refname, sha1, flag, cb_data);
440 static void snarf_refs(int head, int remotes)
442 if (head) {
443 int orig_cnt = ref_name_cnt;
444 for_each_ref(append_head_ref, NULL);
445 sort_ref_range(orig_cnt, ref_name_cnt);
447 if (remotes) {
448 int orig_cnt = ref_name_cnt;
449 for_each_ref(append_remote_ref, NULL);
450 sort_ref_range(orig_cnt, ref_name_cnt);
454 static int rev_is_head(char *head, int headlen, char *name,
455 unsigned char *head_sha1, unsigned char *sha1)
457 if ((!head[0]) ||
458 (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
459 return 0;
460 if (!strncmp(head, "refs/heads/", 11))
461 head += 11;
462 if (!strncmp(name, "refs/heads/", 11))
463 name += 11;
464 else if (!strncmp(name, "heads/", 6))
465 name += 6;
466 return !strcmp(head, name);
469 static int show_merge_base(struct commit_list *seen, int num_rev)
471 int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
472 int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
473 int exit_status = 1;
475 while (seen) {
476 struct commit *commit = pop_one_commit(&seen);
477 int flags = commit->object.flags & all_mask;
478 if (!(flags & UNINTERESTING) &&
479 ((flags & all_revs) == all_revs)) {
480 puts(sha1_to_hex(commit->object.sha1));
481 exit_status = 0;
482 commit->object.flags |= UNINTERESTING;
485 return exit_status;
488 static int show_independent(struct commit **rev,
489 int num_rev,
490 char **ref_name,
491 unsigned int *rev_mask)
493 int i;
495 for (i = 0; i < num_rev; i++) {
496 struct commit *commit = rev[i];
497 unsigned int flag = rev_mask[i];
499 if (commit->object.flags == flag)
500 puts(sha1_to_hex(commit->object.sha1));
501 commit->object.flags |= UNINTERESTING;
503 return 0;
506 static void append_one_rev(const char *av)
508 unsigned char revkey[20];
509 if (!get_sha1(av, revkey)) {
510 append_ref(av, revkey, 0, NULL);
511 return;
513 if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
514 /* glob style match */
515 int saved_matches = ref_name_cnt;
516 match_ref_pattern = av;
517 match_ref_slash = count_slash(av);
518 for_each_ref(append_matching_ref, NULL);
519 if (saved_matches == ref_name_cnt &&
520 ref_name_cnt < MAX_REVS)
521 error("no matching refs with %s", av);
522 if (saved_matches + 1 < ref_name_cnt)
523 sort_ref_range(saved_matches, ref_name_cnt);
524 return;
526 die("bad sha1 reference %s", av);
529 static int git_show_branch_config(const char *var, const char *value)
531 if (!strcmp(var, "showbranch.default")) {
532 if (default_alloc <= default_num + 1) {
533 default_alloc = default_alloc * 3 / 2 + 20;
534 default_arg = xrealloc(default_arg, sizeof *default_arg * default_alloc);
536 default_arg[default_num++] = xstrdup(value);
537 default_arg[default_num] = NULL;
538 return 0;
541 return git_default_config(var, value);
544 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
546 /* If the commit is tip of the named branches, do not
547 * omit it.
548 * Otherwise, if it is a merge that is reachable from only one
549 * tip, it is not that interesting.
551 int i, flag, count;
552 for (i = 0; i < n; i++)
553 if (rev[i] == commit)
554 return 0;
555 flag = commit->object.flags;
556 for (i = count = 0; i < n; i++) {
557 if (flag & (1u << (i + REV_SHIFT)))
558 count++;
560 if (count == 1)
561 return 1;
562 return 0;
565 int cmd_show_branch(int ac, const char **av, const char *prefix)
567 struct commit *rev[MAX_REVS], *commit;
568 struct commit_list *list = NULL, *seen = NULL;
569 unsigned int rev_mask[MAX_REVS];
570 int num_rev, i, extra = 0;
571 int all_heads = 0, all_remotes = 0;
572 int all_mask, all_revs;
573 int lifo = 1;
574 char head[128];
575 const char *head_p;
576 int head_len;
577 unsigned char head_sha1[20];
578 int merge_base = 0;
579 int independent = 0;
580 int no_name = 0;
581 int sha1_name = 0;
582 int shown_merge_point = 0;
583 int with_current_branch = 0;
584 int head_at = -1;
585 int topics = 0;
586 int dense = 1;
587 int reflog = 0;
589 git_config(git_show_branch_config);
591 /* If nothing is specified, try the default first */
592 if (ac == 1 && default_num) {
593 ac = default_num + 1;
594 av = default_arg - 1; /* ick; we would not address av[0] */
597 while (1 < ac && av[1][0] == '-') {
598 const char *arg = av[1];
599 if (!strcmp(arg, "--")) {
600 ac--; av++;
601 break;
603 else if (!strcmp(arg, "--all") || !strcmp(arg, "-a"))
604 all_heads = all_remotes = 1;
605 else if (!strcmp(arg, "--remotes") || !strcmp(arg, "-r"))
606 all_remotes = 1;
607 else if (!strcmp(arg, "--more"))
608 extra = 1;
609 else if (!strcmp(arg, "--list"))
610 extra = -1;
611 else if (!strcmp(arg, "--no-name"))
612 no_name = 1;
613 else if (!strcmp(arg, "--current"))
614 with_current_branch = 1;
615 else if (!strcmp(arg, "--sha1-name"))
616 sha1_name = 1;
617 else if (!strncmp(arg, "--more=", 7))
618 extra = atoi(arg + 7);
619 else if (!strcmp(arg, "--merge-base"))
620 merge_base = 1;
621 else if (!strcmp(arg, "--independent"))
622 independent = 1;
623 else if (!strcmp(arg, "--topo-order"))
624 lifo = 1;
625 else if (!strcmp(arg, "--topics"))
626 topics = 1;
627 else if (!strcmp(arg, "--sparse"))
628 dense = 0;
629 else if (!strcmp(arg, "--date-order"))
630 lifo = 0;
631 else if (!strcmp(arg, "--reflog")) {
632 reflog = DEFAULT_REFLOG;
634 else if (!strncmp(arg, "--reflog=", 9)) {
635 char *end;
636 reflog = strtoul(arg + 9, &end, 10);
637 if (*end != '\0')
638 die("unrecognized reflog count '%s'", arg + 9);
640 else
641 usage(show_branch_usage);
642 ac--; av++;
644 ac--; av++;
646 /* Only one of these is allowed */
647 if (1 < independent + merge_base + (extra != 0) + (!!reflog))
648 usage(show_branch_usage);
650 /* If nothing is specified, show all branches by default */
651 if (ac + all_heads + all_remotes == 0)
652 all_heads = 1;
654 if (all_heads + all_remotes)
655 snarf_refs(all_heads, all_remotes);
656 if (reflog) {
657 int reflen;
658 if (!ac)
659 die("--reflog option needs one branch name");
660 reflen = strlen(*av);
661 for (i = 0; i < reflog; i++) {
662 char *name = xmalloc(reflen + 20);
663 sprintf(name, "%s@{%d}", *av, i);
664 append_one_rev(name);
667 else {
668 while (0 < ac) {
669 append_one_rev(*av);
670 ac--; av++;
674 head_p = resolve_ref("HEAD", head_sha1, 1, NULL);
675 if (head_p) {
676 head_len = strlen(head_p);
677 memcpy(head, head_p, head_len + 1);
679 else {
680 head_len = 0;
681 head[0] = 0;
684 if (with_current_branch && head_p) {
685 int has_head = 0;
686 for (i = 0; !has_head && i < ref_name_cnt; i++) {
687 /* We are only interested in adding the branch
688 * HEAD points at.
690 if (rev_is_head(head,
691 head_len,
692 ref_name[i],
693 head_sha1, NULL))
694 has_head++;
696 if (!has_head) {
697 int pfxlen = strlen("refs/heads/");
698 append_one_rev(head + pfxlen);
702 if (!ref_name_cnt) {
703 fprintf(stderr, "No revs to be shown.\n");
704 exit(0);
707 for (num_rev = 0; ref_name[num_rev]; num_rev++) {
708 unsigned char revkey[20];
709 unsigned int flag = 1u << (num_rev + REV_SHIFT);
711 if (MAX_REVS <= num_rev)
712 die("cannot handle more than %d revs.", MAX_REVS);
713 if (get_sha1(ref_name[num_rev], revkey))
714 die("'%s' is not a valid ref.", ref_name[num_rev]);
715 commit = lookup_commit_reference(revkey);
716 if (!commit)
717 die("cannot find commit %s (%s)",
718 ref_name[num_rev], revkey);
719 parse_commit(commit);
720 mark_seen(commit, &seen);
722 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
723 * and so on. REV_SHIFT bits from bit 0 are used for
724 * internal bookkeeping.
726 commit->object.flags |= flag;
727 if (commit->object.flags == flag)
728 insert_by_date(commit, &list);
729 rev[num_rev] = commit;
731 for (i = 0; i < num_rev; i++)
732 rev_mask[i] = rev[i]->object.flags;
734 if (0 <= extra)
735 join_revs(&list, &seen, num_rev, extra);
737 sort_by_date(&seen);
739 if (merge_base)
740 return show_merge_base(seen, num_rev);
742 if (independent)
743 return show_independent(rev, num_rev, ref_name, rev_mask);
745 /* Show list; --more=-1 means list-only */
746 if (1 < num_rev || extra < 0) {
747 for (i = 0; i < num_rev; i++) {
748 int j;
749 int is_head = rev_is_head(head,
750 head_len,
751 ref_name[i],
752 head_sha1,
753 rev[i]->object.sha1);
754 if (extra < 0)
755 printf("%c [%s] ",
756 is_head ? '*' : ' ', ref_name[i]);
757 else {
758 for (j = 0; j < i; j++)
759 putchar(' ');
760 printf("%c [%s] ",
761 is_head ? '*' : '!', ref_name[i]);
763 /* header lines never need name */
764 show_one_commit(rev[i], 1);
765 if (is_head)
766 head_at = i;
768 if (0 <= extra) {
769 for (i = 0; i < num_rev; i++)
770 putchar('-');
771 putchar('\n');
774 if (extra < 0)
775 exit(0);
777 /* Sort topologically */
778 sort_in_topological_order(&seen, lifo);
780 /* Give names to commits */
781 if (!sha1_name && !no_name)
782 name_commits(seen, rev, ref_name, num_rev);
784 all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
785 all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
787 while (seen) {
788 struct commit *commit = pop_one_commit(&seen);
789 int this_flag = commit->object.flags;
790 int is_merge_point = ((this_flag & all_revs) == all_revs);
792 shown_merge_point |= is_merge_point;
794 if (1 < num_rev) {
795 int is_merge = !!(commit->parents &&
796 commit->parents->next);
797 if (topics &&
798 !is_merge_point &&
799 (this_flag & (1u << REV_SHIFT)))
800 continue;
801 if (dense && is_merge &&
802 omit_in_dense(commit, rev, num_rev))
803 continue;
804 for (i = 0; i < num_rev; i++) {
805 int mark;
806 if (!(this_flag & (1u << (i + REV_SHIFT))))
807 mark = ' ';
808 else if (is_merge)
809 mark = '-';
810 else if (i == head_at)
811 mark = '*';
812 else
813 mark = '+';
814 putchar(mark);
816 putchar(' ');
818 show_one_commit(commit, no_name);
820 if (shown_merge_point && --extra < 0)
821 break;
823 return 0;