git svn: catch lack of upstream info for dcommit earlier
[git] / builtin-show-branch.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "refs.h"
4 #include "builtin.h"
5
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[,b]] <branch>";
8 static const char show_branch_usage_reflog[] =
9 "--reflog is incompatible with --all, --remotes, --independent or --merge-base";
10
11 static int default_num;
12 static int default_alloc;
13 static const char **default_arg;
14
15 #define UNINTERESTING   01
16
17 #define REV_SHIFT        2
18 #define MAX_REVS        (FLAG_BITS - REV_SHIFT) /* should not exceed bits_per_int - REV_SHIFT */
19
20 #define DEFAULT_REFLOG  4
21
22 static struct commit *interesting(struct commit_list *list)
23 {
24         while (list) {
25                 struct commit *commit = list->item;
26                 list = list->next;
27                 if (commit->object.flags & UNINTERESTING)
28                         continue;
29                 return commit;
30         }
31         return NULL;
32 }
33
34 static struct commit *pop_one_commit(struct commit_list **list_p)
35 {
36         struct commit *commit;
37         struct commit_list *list;
38         list = *list_p;
39         commit = list->item;
40         *list_p = list->next;
41         free(list);
42         return commit;
43 }
44
45 struct commit_name {
46         const char *head_name; /* which head's ancestor? */
47         int generation; /* how many parents away from head_name */
48 };
49
50 /* Name the commit as nth generation ancestor of head_name;
51  * we count only the first-parent relationship for naming purposes.
52  */
53 static void name_commit(struct commit *commit, const char *head_name, int nth)
54 {
55         struct commit_name *name;
56         if (!commit->util)
57                 commit->util = xmalloc(sizeof(struct commit_name));
58         name = commit->util;
59         name->head_name = head_name;
60         name->generation = nth;
61 }
62
63 /* Parent is the first parent of the commit.  We may name it
64  * as (n+1)th generation ancestor of the same head_name as
65  * commit is nth generation ancestor of, if that generation
66  * number is better than the name it already has.
67  */
68 static void name_parent(struct commit *commit, struct commit *parent)
69 {
70         struct commit_name *commit_name = commit->util;
71         struct commit_name *parent_name = parent->util;
72         if (!commit_name)
73                 return;
74         if (!parent_name ||
75             commit_name->generation + 1 < parent_name->generation)
76                 name_commit(parent, commit_name->head_name,
77                             commit_name->generation + 1);
78 }
79
80 static int name_first_parent_chain(struct commit *c)
81 {
82         int i = 0;
83         while (c) {
84                 struct commit *p;
85                 if (!c->util)
86                         break;
87                 if (!c->parents)
88                         break;
89                 p = c->parents->item;
90                 if (!p->util) {
91                         name_parent(c, p);
92                         i++;
93                 }
94                 else
95                         break;
96                 c = p;
97         }
98         return i;
99 }
100
101 static void name_commits(struct commit_list *list,
102                          struct commit **rev,
103                          char **ref_name,
104                          int num_rev)
105 {
106         struct commit_list *cl;
107         struct commit *c;
108         int i;
109
110         /* First give names to the given heads */
111         for (cl = list; cl; cl = cl->next) {
112                 c = cl->item;
113                 if (c->util)
114                         continue;
115                 for (i = 0; i < num_rev; i++) {
116                         if (rev[i] == c) {
117                                 name_commit(c, ref_name[i], 0);
118                                 break;
119                         }
120                 }
121         }
122
123         /* Then commits on the first parent ancestry chain */
124         do {
125                 i = 0;
126                 for (cl = list; cl; cl = cl->next) {
127                         i += name_first_parent_chain(cl->item);
128                 }
129         } while (i);
130
131         /* Finally, any unnamed commits */
132         do {
133                 i = 0;
134                 for (cl = list; cl; cl = cl->next) {
135                         struct commit_list *parents;
136                         struct commit_name *n;
137                         int nth;
138                         c = cl->item;
139                         if (!c->util)
140                                 continue;
141                         n = c->util;
142                         parents = c->parents;
143                         nth = 0;
144                         while (parents) {
145                                 struct commit *p = parents->item;
146                                 char newname[1000], *en;
147                                 parents = parents->next;
148                                 nth++;
149                                 if (p->util)
150                                         continue;
151                                 en = newname;
152                                 switch (n->generation) {
153                                 case 0:
154                                         en += sprintf(en, "%s", n->head_name);
155                                         break;
156                                 case 1:
157                                         en += sprintf(en, "%s^", n->head_name);
158                                         break;
159                                 default:
160                                         en += sprintf(en, "%s~%d",
161                                                 n->head_name, n->generation);
162                                         break;
163                                 }
164                                 if (nth == 1)
165                                         en += sprintf(en, "^");
166                                 else
167                                         en += sprintf(en, "^%d", nth);
168                                 name_commit(p, xstrdup(newname), 0);
169                                 i++;
170                                 name_first_parent_chain(p);
171                         }
172                 }
173         } while (i);
174 }
175
176 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
177 {
178         if (!commit->object.flags) {
179                 commit_list_insert(commit, seen_p);
180                 return 1;
181         }
182         return 0;
183 }
184
185 static void join_revs(struct commit_list **list_p,
186                       struct commit_list **seen_p,
187                       int num_rev, int extra)
188 {
189         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
190         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
191
192         while (*list_p) {
193                 struct commit_list *parents;
194                 int still_interesting = !!interesting(*list_p);
195                 struct commit *commit = pop_one_commit(list_p);
196                 int flags = commit->object.flags & all_mask;
197
198                 if (!still_interesting && extra <= 0)
199                         break;
200
201                 mark_seen(commit, seen_p);
202                 if ((flags & all_revs) == all_revs)
203                         flags |= UNINTERESTING;
204                 parents = commit->parents;
205
206                 while (parents) {
207                         struct commit *p = parents->item;
208                         int this_flag = p->object.flags;
209                         parents = parents->next;
210                         if ((this_flag & flags) == flags)
211                                 continue;
212                         if (!p->object.parsed)
213                                 parse_commit(p);
214                         if (mark_seen(p, seen_p) && !still_interesting)
215                                 extra--;
216                         p->object.flags |= flags;
217                         insert_by_date(p, list_p);
218                 }
219         }
220
221         /*
222          * Postprocess to complete well-poisoning.
223          *
224          * At this point we have all the commits we have seen in
225          * seen_p list.  Mark anything that can be reached from
226          * uninteresting commits not interesting.
227          */
228         for (;;) {
229                 int changed = 0;
230                 struct commit_list *s;
231                 for (s = *seen_p; s; s = s->next) {
232                         struct commit *c = s->item;
233                         struct commit_list *parents;
234
235                         if (((c->object.flags & all_revs) != all_revs) &&
236                             !(c->object.flags & UNINTERESTING))
237                                 continue;
238
239                         /* The current commit is either a merge base or
240                          * already uninteresting one.  Mark its parents
241                          * as uninteresting commits _only_ if they are
242                          * already parsed.  No reason to find new ones
243                          * here.
244                          */
245                         parents = c->parents;
246                         while (parents) {
247                                 struct commit *p = parents->item;
248                                 parents = parents->next;
249                                 if (!(p->object.flags & UNINTERESTING)) {
250                                         p->object.flags |= UNINTERESTING;
251                                         changed = 1;
252                                 }
253                         }
254                 }
255                 if (!changed)
256                         break;
257         }
258 }
259
260 static void show_one_commit(struct commit *commit, int no_name)
261 {
262         struct strbuf pretty;
263         const char *pretty_str = "(unavailable)";
264         struct commit_name *name = commit->util;
265
266         strbuf_init(&pretty, 0);
267         if (commit->object.parsed) {
268                 pretty_print_commit(CMIT_FMT_ONELINE, commit,
269                                     &pretty, 0, NULL, NULL, 0, 0);
270                 pretty_str = pretty.buf;
271         }
272         if (!prefixcmp(pretty_str, "[PATCH] "))
273                 pretty_str += 8;
274
275         if (!no_name) {
276                 if (name && name->head_name) {
277                         printf("[%s", name->head_name);
278                         if (name->generation) {
279                                 if (name->generation == 1)
280                                         printf("^");
281                                 else
282                                         printf("~%d", name->generation);
283                         }
284                         printf("] ");
285                 }
286                 else
287                         printf("[%s] ",
288                                find_unique_abbrev(commit->object.sha1, 7));
289         }
290         puts(pretty_str);
291         strbuf_release(&pretty);
292 }
293
294 static char *ref_name[MAX_REVS + 1];
295 static int ref_name_cnt;
296
297 static const char *find_digit_prefix(const char *s, int *v)
298 {
299         const char *p;
300         int ver;
301         char ch;
302
303         for (p = s, ver = 0;
304              '0' <= (ch = *p) && ch <= '9';
305              p++)
306                 ver = ver * 10 + ch - '0';
307         *v = ver;
308         return p;
309 }
310
311
312 static int version_cmp(const char *a, const char *b)
313 {
314         while (1) {
315                 int va, vb;
316
317                 a = find_digit_prefix(a, &va);
318                 b = find_digit_prefix(b, &vb);
319                 if (va != vb)
320                         return va - vb;
321
322                 while (1) {
323                         int ca = *a;
324                         int cb = *b;
325                         if ('0' <= ca && ca <= '9')
326                                 ca = 0;
327                         if ('0' <= cb && cb <= '9')
328                                 cb = 0;
329                         if (ca != cb)
330                                 return ca - cb;
331                         if (!ca)
332                                 break;
333                         a++;
334                         b++;
335                 }
336                 if (!*a && !*b)
337                         return 0;
338         }
339 }
340
341 static int compare_ref_name(const void *a_, const void *b_)
342 {
343         const char * const*a = a_, * const*b = b_;
344         return version_cmp(*a, *b);
345 }
346
347 static void sort_ref_range(int bottom, int top)
348 {
349         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
350               compare_ref_name);
351 }
352
353 static int append_ref(const char *refname, const unsigned char *sha1,
354                       int allow_dups)
355 {
356         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
357         int i;
358
359         if (!commit)
360                 return 0;
361
362         if (!allow_dups) {
363                 /* Avoid adding the same thing twice */
364                 for (i = 0; i < ref_name_cnt; i++)
365                         if (!strcmp(refname, ref_name[i]))
366                                 return 0;
367         }
368         if (MAX_REVS <= ref_name_cnt) {
369                 fprintf(stderr, "warning: ignoring %s; "
370                         "cannot handle more than %d refs\n",
371                         refname, MAX_REVS);
372                 return 0;
373         }
374         ref_name[ref_name_cnt++] = xstrdup(refname);
375         ref_name[ref_name_cnt] = NULL;
376         return 0;
377 }
378
379 static int append_head_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
380 {
381         unsigned char tmp[20];
382         int ofs = 11;
383         if (prefixcmp(refname, "refs/heads/"))
384                 return 0;
385         /* If both heads/foo and tags/foo exists, get_sha1 would
386          * get confused.
387          */
388         if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
389                 ofs = 5;
390         return append_ref(refname + ofs, sha1, 0);
391 }
392
393 static int append_remote_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
394 {
395         unsigned char tmp[20];
396         int ofs = 13;
397         if (prefixcmp(refname, "refs/remotes/"))
398                 return 0;
399         /* If both heads/foo and tags/foo exists, get_sha1 would
400          * get confused.
401          */
402         if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
403                 ofs = 5;
404         return append_ref(refname + ofs, sha1, 0);
405 }
406
407 static int append_tag_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
408 {
409         if (prefixcmp(refname, "refs/tags/"))
410                 return 0;
411         return append_ref(refname + 5, sha1, 0);
412 }
413
414 static const char *match_ref_pattern = NULL;
415 static int match_ref_slash = 0;
416 static int count_slash(const char *s)
417 {
418         int cnt = 0;
419         while (*s)
420                 if (*s++ == '/')
421                         cnt++;
422         return cnt;
423 }
424
425 static int append_matching_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
426 {
427         /* we want to allow pattern hold/<asterisk> to show all
428          * branches under refs/heads/hold/, and v0.99.9? to show
429          * refs/tags/v0.99.9a and friends.
430          */
431         const char *tail;
432         int slash = count_slash(refname);
433         for (tail = refname; *tail && match_ref_slash < slash; )
434                 if (*tail++ == '/')
435                         slash--;
436         if (!*tail)
437                 return 0;
438         if (fnmatch(match_ref_pattern, tail, 0))
439                 return 0;
440         if (!prefixcmp(refname, "refs/heads/"))
441                 return append_head_ref(refname, sha1, flag, cb_data);
442         if (!prefixcmp(refname, "refs/tags/"))
443                 return append_tag_ref(refname, sha1, flag, cb_data);
444         return append_ref(refname, sha1, 0);
445 }
446
447 static void snarf_refs(int head, int remotes)
448 {
449         if (head) {
450                 int orig_cnt = ref_name_cnt;
451                 for_each_ref(append_head_ref, NULL);
452                 sort_ref_range(orig_cnt, ref_name_cnt);
453         }
454         if (remotes) {
455                 int orig_cnt = ref_name_cnt;
456                 for_each_ref(append_remote_ref, NULL);
457                 sort_ref_range(orig_cnt, ref_name_cnt);
458         }
459 }
460
461 static int rev_is_head(char *head, int headlen, char *name,
462                        unsigned char *head_sha1, unsigned char *sha1)
463 {
464         if ((!head[0]) ||
465             (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
466                 return 0;
467         if (!prefixcmp(head, "refs/heads/"))
468                 head += 11;
469         if (!prefixcmp(name, "refs/heads/"))
470                 name += 11;
471         else if (!prefixcmp(name, "heads/"))
472                 name += 6;
473         return !strcmp(head, name);
474 }
475
476 static int show_merge_base(struct commit_list *seen, int num_rev)
477 {
478         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
479         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
480         int exit_status = 1;
481
482         while (seen) {
483                 struct commit *commit = pop_one_commit(&seen);
484                 int flags = commit->object.flags & all_mask;
485                 if (!(flags & UNINTERESTING) &&
486                     ((flags & all_revs) == all_revs)) {
487                         puts(sha1_to_hex(commit->object.sha1));
488                         exit_status = 0;
489                         commit->object.flags |= UNINTERESTING;
490                 }
491         }
492         return exit_status;
493 }
494
495 static int show_independent(struct commit **rev,
496                             int num_rev,
497                             char **ref_name,
498                             unsigned int *rev_mask)
499 {
500         int i;
501
502         for (i = 0; i < num_rev; i++) {
503                 struct commit *commit = rev[i];
504                 unsigned int flag = rev_mask[i];
505
506                 if (commit->object.flags == flag)
507                         puts(sha1_to_hex(commit->object.sha1));
508                 commit->object.flags |= UNINTERESTING;
509         }
510         return 0;
511 }
512
513 static void append_one_rev(const char *av)
514 {
515         unsigned char revkey[20];
516         if (!get_sha1(av, revkey)) {
517                 append_ref(av, revkey, 0);
518                 return;
519         }
520         if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
521                 /* glob style match */
522                 int saved_matches = ref_name_cnt;
523                 match_ref_pattern = av;
524                 match_ref_slash = count_slash(av);
525                 for_each_ref(append_matching_ref, NULL);
526                 if (saved_matches == ref_name_cnt &&
527                     ref_name_cnt < MAX_REVS)
528                         error("no matching refs with %s", av);
529                 if (saved_matches + 1 < ref_name_cnt)
530                         sort_ref_range(saved_matches, ref_name_cnt);
531                 return;
532         }
533         die("bad sha1 reference %s", av);
534 }
535
536 static int git_show_branch_config(const char *var, const char *value, void *cb)
537 {
538         if (!strcmp(var, "showbranch.default")) {
539                 if (!value)
540                         return config_error_nonbool(var);
541                 if (default_alloc <= default_num + 1) {
542                         default_alloc = default_alloc * 3 / 2 + 20;
543                         default_arg = xrealloc(default_arg, sizeof *default_arg * default_alloc);
544                 }
545                 default_arg[default_num++] = xstrdup(value);
546                 default_arg[default_num] = NULL;
547                 return 0;
548         }
549
550         return git_default_config(var, value, cb);
551 }
552
553 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
554 {
555         /* If the commit is tip of the named branches, do not
556          * omit it.
557          * Otherwise, if it is a merge that is reachable from only one
558          * tip, it is not that interesting.
559          */
560         int i, flag, count;
561         for (i = 0; i < n; i++)
562                 if (rev[i] == commit)
563                         return 0;
564         flag = commit->object.flags;
565         for (i = count = 0; i < n; i++) {
566                 if (flag & (1u << (i + REV_SHIFT)))
567                         count++;
568         }
569         if (count == 1)
570                 return 1;
571         return 0;
572 }
573
574 static void parse_reflog_param(const char *arg, int *cnt, const char **base)
575 {
576         char *ep;
577         *cnt = strtoul(arg, &ep, 10);
578         if (*ep == ',')
579                 *base = ep + 1;
580         else if (*ep)
581                 die("unrecognized reflog param '%s'", arg + 9);
582         else
583                 *base = NULL;
584         if (*cnt <= 0)
585                 *cnt = DEFAULT_REFLOG;
586 }
587
588 int cmd_show_branch(int ac, const char **av, const char *prefix)
589 {
590         struct commit *rev[MAX_REVS], *commit;
591         char *reflog_msg[MAX_REVS];
592         struct commit_list *list = NULL, *seen = NULL;
593         unsigned int rev_mask[MAX_REVS];
594         int num_rev, i, extra = 0;
595         int all_heads = 0, all_remotes = 0;
596         int all_mask, all_revs;
597         int lifo = 1;
598         char head[128];
599         const char *head_p;
600         int head_len;
601         unsigned char head_sha1[20];
602         int merge_base = 0;
603         int independent = 0;
604         int no_name = 0;
605         int sha1_name = 0;
606         int shown_merge_point = 0;
607         int with_current_branch = 0;
608         int head_at = -1;
609         int topics = 0;
610         int dense = 1;
611         int reflog = 0;
612         const char *reflog_base = NULL;
613
614         git_config(git_show_branch_config, NULL);
615
616         /* If nothing is specified, try the default first */
617         if (ac == 1 && default_num) {
618                 ac = default_num + 1;
619                 av = default_arg - 1; /* ick; we would not address av[0] */
620         }
621
622         while (1 < ac && av[1][0] == '-') {
623                 const char *arg = av[1];
624                 if (!strcmp(arg, "--")) {
625                         ac--; av++;
626                         break;
627                 }
628                 else if (!strcmp(arg, "--all") || !strcmp(arg, "-a"))
629                         all_heads = all_remotes = 1;
630                 else if (!strcmp(arg, "--remotes") || !strcmp(arg, "-r"))
631                         all_remotes = 1;
632                 else if (!strcmp(arg, "--more"))
633                         extra = 1;
634                 else if (!strcmp(arg, "--list"))
635                         extra = -1;
636                 else if (!strcmp(arg, "--no-name"))
637                         no_name = 1;
638                 else if (!strcmp(arg, "--current"))
639                         with_current_branch = 1;
640                 else if (!strcmp(arg, "--sha1-name"))
641                         sha1_name = 1;
642                 else if (!prefixcmp(arg, "--more="))
643                         extra = atoi(arg + 7);
644                 else if (!strcmp(arg, "--merge-base"))
645                         merge_base = 1;
646                 else if (!strcmp(arg, "--independent"))
647                         independent = 1;
648                 else if (!strcmp(arg, "--topo-order"))
649                         lifo = 1;
650                 else if (!strcmp(arg, "--topics"))
651                         topics = 1;
652                 else if (!strcmp(arg, "--sparse"))
653                         dense = 0;
654                 else if (!strcmp(arg, "--date-order"))
655                         lifo = 0;
656                 else if (!strcmp(arg, "--reflog") || !strcmp(arg, "-g")) {
657                         reflog = DEFAULT_REFLOG;
658                 }
659                 else if (!prefixcmp(arg, "--reflog="))
660                         parse_reflog_param(arg + 9, &reflog, &reflog_base);
661                 else if (!prefixcmp(arg, "-g="))
662                         parse_reflog_param(arg + 3, &reflog, &reflog_base);
663                 else
664                         usage(show_branch_usage);
665                 ac--; av++;
666         }
667         ac--; av++;
668
669         if (extra || reflog) {
670                 /* "listing" mode is incompatible with
671                  * independent nor merge-base modes.
672                  */
673                 if (independent || merge_base)
674                         usage(show_branch_usage);
675                 if (reflog && ((0 < extra) || all_heads || all_remotes))
676                         /*
677                          * Asking for --more in reflog mode does not
678                          * make sense.  --list is Ok.
679                          *
680                          * Also --all and --remotes do not make sense either.
681                          */
682                         usage(show_branch_usage_reflog);
683         }
684
685         /* If nothing is specified, show all branches by default */
686         if (ac + all_heads + all_remotes == 0)
687                 all_heads = 1;
688
689         if (reflog) {
690                 unsigned char sha1[20];
691                 char nth_desc[256];
692                 char *ref;
693                 int base = 0;
694
695                 if (ac == 0) {
696                         static const char *fake_av[2];
697                         const char *refname;
698
699                         refname = resolve_ref("HEAD", sha1, 1, NULL);
700                         fake_av[0] = xstrdup(refname);
701                         fake_av[1] = NULL;
702                         av = fake_av;
703                         ac = 1;
704                 }
705                 if (ac != 1)
706                         die("--reflog option needs one branch name");
707
708                 if (MAX_REVS < reflog)
709                         die("Only %d entries can be shown at one time.",
710                             MAX_REVS);
711                 if (!dwim_ref(*av, strlen(*av), sha1, &ref))
712                         die("No such ref %s", *av);
713
714                 /* Has the base been specified? */
715                 if (reflog_base) {
716                         char *ep;
717                         base = strtoul(reflog_base, &ep, 10);
718                         if (*ep) {
719                                 /* Ah, that is a date spec... */
720                                 unsigned long at;
721                                 at = approxidate(reflog_base);
722                                 read_ref_at(ref, at, -1, sha1, NULL,
723                                             NULL, NULL, &base);
724                         }
725                 }
726
727                 for (i = 0; i < reflog; i++) {
728                         char *logmsg, *m;
729                         const char *msg;
730                         unsigned long timestamp;
731                         int tz;
732
733                         if (read_ref_at(ref, 0, base+i, sha1, &logmsg,
734                                         &timestamp, &tz, NULL)) {
735                                 reflog = i;
736                                 break;
737                         }
738                         msg = strchr(logmsg, '\t');
739                         if (!msg)
740                                 msg = "(none)";
741                         else
742                                 msg++;
743                         m = xmalloc(strlen(msg) + 200);
744                         sprintf(m, "(%s) %s",
745                                 show_date(timestamp, tz, 1),
746                                 msg);
747                         reflog_msg[i] = m;
748                         free(logmsg);
749                         sprintf(nth_desc, "%s@{%d}", *av, base+i);
750                         append_ref(nth_desc, sha1, 1);
751                 }
752         }
753         else if (all_heads + all_remotes)
754                 snarf_refs(all_heads, all_remotes);
755         else {
756                 while (0 < ac) {
757                         append_one_rev(*av);
758                         ac--; av++;
759                 }
760         }
761
762         head_p = resolve_ref("HEAD", head_sha1, 1, NULL);
763         if (head_p) {
764                 head_len = strlen(head_p);
765                 memcpy(head, head_p, head_len + 1);
766         }
767         else {
768                 head_len = 0;
769                 head[0] = 0;
770         }
771
772         if (with_current_branch && head_p) {
773                 int has_head = 0;
774                 for (i = 0; !has_head && i < ref_name_cnt; i++) {
775                         /* We are only interested in adding the branch
776                          * HEAD points at.
777                          */
778                         if (rev_is_head(head,
779                                         head_len,
780                                         ref_name[i],
781                                         head_sha1, NULL))
782                                 has_head++;
783                 }
784                 if (!has_head) {
785                         int offset = !prefixcmp(head, "refs/heads/") ? 11 : 0;
786                         append_one_rev(head + offset);
787                 }
788         }
789
790         if (!ref_name_cnt) {
791                 fprintf(stderr, "No revs to be shown.\n");
792                 exit(0);
793         }
794
795         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
796                 unsigned char revkey[20];
797                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
798
799                 if (MAX_REVS <= num_rev)
800                         die("cannot handle more than %d revs.", MAX_REVS);
801                 if (get_sha1(ref_name[num_rev], revkey))
802                         die("'%s' is not a valid ref.", ref_name[num_rev]);
803                 commit = lookup_commit_reference(revkey);
804                 if (!commit)
805                         die("cannot find commit %s (%s)",
806                             ref_name[num_rev], revkey);
807                 parse_commit(commit);
808                 mark_seen(commit, &seen);
809
810                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
811                  * and so on.  REV_SHIFT bits from bit 0 are used for
812                  * internal bookkeeping.
813                  */
814                 commit->object.flags |= flag;
815                 if (commit->object.flags == flag)
816                         insert_by_date(commit, &list);
817                 rev[num_rev] = commit;
818         }
819         for (i = 0; i < num_rev; i++)
820                 rev_mask[i] = rev[i]->object.flags;
821
822         if (0 <= extra)
823                 join_revs(&list, &seen, num_rev, extra);
824
825         sort_by_date(&seen);
826
827         if (merge_base)
828                 return show_merge_base(seen, num_rev);
829
830         if (independent)
831                 return show_independent(rev, num_rev, ref_name, rev_mask);
832
833         /* Show list; --more=-1 means list-only */
834         if (1 < num_rev || extra < 0) {
835                 for (i = 0; i < num_rev; i++) {
836                         int j;
837                         int is_head = rev_is_head(head,
838                                                   head_len,
839                                                   ref_name[i],
840                                                   head_sha1,
841                                                   rev[i]->object.sha1);
842                         if (extra < 0)
843                                 printf("%c [%s] ",
844                                        is_head ? '*' : ' ', ref_name[i]);
845                         else {
846                                 for (j = 0; j < i; j++)
847                                         putchar(' ');
848                                 printf("%c [%s] ",
849                                        is_head ? '*' : '!', ref_name[i]);
850                         }
851
852                         if (!reflog) {
853                                 /* header lines never need name */
854                                 show_one_commit(rev[i], 1);
855                         }
856                         else
857                                 puts(reflog_msg[i]);
858
859                         if (is_head)
860                                 head_at = i;
861                 }
862                 if (0 <= extra) {
863                         for (i = 0; i < num_rev; i++)
864                                 putchar('-');
865                         putchar('\n');
866                 }
867         }
868         if (extra < 0)
869                 exit(0);
870
871         /* Sort topologically */
872         sort_in_topological_order(&seen, lifo);
873
874         /* Give names to commits */
875         if (!sha1_name && !no_name)
876                 name_commits(seen, rev, ref_name, num_rev);
877
878         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
879         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
880
881         while (seen) {
882                 struct commit *commit = pop_one_commit(&seen);
883                 int this_flag = commit->object.flags;
884                 int is_merge_point = ((this_flag & all_revs) == all_revs);
885
886                 shown_merge_point |= is_merge_point;
887
888                 if (1 < num_rev) {
889                         int is_merge = !!(commit->parents &&
890                                           commit->parents->next);
891                         if (topics &&
892                             !is_merge_point &&
893                             (this_flag & (1u << REV_SHIFT)))
894                                 continue;
895                         if (dense && is_merge &&
896                             omit_in_dense(commit, rev, num_rev))
897                                 continue;
898                         for (i = 0; i < num_rev; i++) {
899                                 int mark;
900                                 if (!(this_flag & (1u << (i + REV_SHIFT))))
901                                         mark = ' ';
902                                 else if (is_merge)
903                                         mark = '-';
904                                 else if (i == head_at)
905                                         mark = '*';
906                                 else
907                                         mark = '+';
908                                 putchar(mark);
909                         }
910                         putchar(' ');
911                 }
912                 show_one_commit(commit, no_name);
913
914                 if (shown_merge_point && --extra < 0)
915                         break;
916         }
917         return 0;
918 }