builtin-show-branch.c

   1 #include <stdlib.h>
   2 #include <fnmatch.h>
   3 #include "cache.h"
   4 #include "commit.h"
   5 #include "refs.h"
   6 #include "builtin.h"
   7
   8 static const char show_branch_usage[] =
   9 "git-show-branch [--dense] [--current] [--all] [--heads] [--tags] [--topo-order] [--more=count | --list | --independent | --merge-base ] [--topics] [<refs>...]";
  10
  11 static int default_num = 0;
  12 static int default_alloc = 0;
  13 static const char **default_arg = NULL;
  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 static struct commit *interesting(struct commit_list *list)
  21 {
  22         while (list) {
  23                 struct commit *commit = list->item;
  24                 list = list->next;
  25                 if (commit->object.flags & UNINTERESTING)
  26                         continue;
  27                 return commit;
  28         }
  29         return NULL;
  30 }
  31
  32 static struct commit *pop_one_commit(struct commit_list **list_p)
  33 {
  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;
  41 }
  42
  43 struct commit_name {
  44         const char *head_name; /* which head's ancestor? */
  45         int generation; /* how many parents away from head_name */
  46 };
  47
  48 /* Name the commit as nth generation ancestor of head_name;
  49  * we count only the first-parent relationship for naming purposes.
  50  */
  51 static void name_commit(struct commit *commit, const char *head_name, int nth)
  52 {
  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;
  59 }
  60
  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.
  65  */
  66 static void name_parent(struct commit *commit, struct commit *parent)
  67 {
  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);
  76 }
  77
  78 static int name_first_parent_chain(struct commit *c)
  79 {
  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++;
  91                 }
  92                 c = p;
  93         }
  94         return i;
  95 }
  96
  97 static void name_commits(struct commit_list *list,
  98                          struct commit **rev,
  99                          char **ref_name,
 100                          int num_rev)
 101 {
 102         struct commit_list *cl;
 103         struct commit *c;
 104         int i;
 105
 106         /* First give names to the given heads */
 107         for (cl = list; cl; cl = cl->next) {
 108                 c = cl->item;
 109                 if (c->util)
 110                         continue;
 111                 for (i = 0; i < num_rev; i++) {
 112                         if (rev[i] == c) {
 113                                 name_commit(c, ref_name[i], 0);
 114                                 break;
 115                         }
 116                 }
 117         }
 118
 119         /* Then commits on the first parent ancestry chain */
 120         do {
 121                 i = 0;
 122                 for (cl = list; cl; cl = cl->next) {
 123                         i += name_first_parent_chain(cl->item);
 124                 }
 125         } while (i);
 126
 127         /* Finally, any unnamed commits */
 128         do {
 129                 i = 0;
 130                 for (cl = list; cl; cl = cl->next) {
 131                         struct commit_list *parents;
 132                         struct commit_name *n;
 133                         int nth;
 134                         c = cl->item;
 135                         if (!c->util)
 136                                 continue;
 137                         n = c->util;
 138                         parents = c->parents;
 139                         nth = 0;
 140                         while (parents) {
 141                                 struct commit *p = parents->item;
 142                                 char newname[1000], *en;
 143                                 parents = parents->next;
 144                                 nth++;
 145                                 if (p->util)
 146                                         continue;
 147                                 en = newname;
 148                                 switch (n->generation) {
 149                                 case 0:
 150                                         en += sprintf(en, "%s", n->head_name);
 151                                         break;
 152                                 case 1:
 153                                         en += sprintf(en, "%s^", n->head_name);
 154                                         break;
 155                                 default:
 156                                         en += sprintf(en, "%s~%d",
 157                                                 n->head_name, n->generation);
 158                                         break;
 159                                 }
 160                                 if (nth == 1)
 161                                         en += sprintf(en, "^");
 162                                 else
 163                                         en += sprintf(en, "^%d", nth);
 164                                 name_commit(p, strdup(newname), 0);
 165                                 i++;
 166                                 name_first_parent_chain(p);
 167                         }
 168                 }
 169         } while (i);
 170 }
 171
 172 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 173 {
 174         if (!commit->object.flags) {
 175                 insert_by_date(commit, seen_p);
 176                 return 1;
 177         }
 178         return 0;
 179 }
 180
 181 static void join_revs(struct commit_list **list_p,
 182                       struct commit_list **seen_p,
 183                       int num_rev, int extra)
 184 {
 185         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 186         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 187
 188         while (*list_p) {
 189                 struct commit_list *parents;
 190                 int still_interesting = !!interesting(*list_p);
 191                 struct commit *commit = pop_one_commit(list_p);
 192                 int flags = commit->object.flags & all_mask;
 193
 194                 if (!still_interesting && extra <= 0)
 195                         break;
 196
 197                 mark_seen(commit, seen_p);
 198                 if ((flags & all_revs) == all_revs)
 199                         flags |= UNINTERESTING;
 200                 parents = commit->parents;
 201
 202                 while (parents) {
 203                         struct commit *p = parents->item;
 204                         int this_flag = p->object.flags;
 205                         parents = parents->next;
 206                         if ((this_flag & flags) == flags)
 207                                 continue;
 208                         if (!p->object.parsed)
 209                                 parse_commit(p);
 210                         if (mark_seen(p, seen_p) && !still_interesting)
 211                                 extra--;
 212                         p->object.flags |= flags;
 213                         insert_by_date(p, list_p);
 214                 }
 215         }
 216
 217         /*
 218          * Postprocess to complete well-poisoning.
 219          *
 220          * At this point we have all the commits we have seen in
 221          * seen_p list (which happens to be sorted chronologically but
 222          * it does not really matter).  Mark anything that can be
 223          * reached from uninteresting commits not interesting.
 224          */
 225         for (;;) {
 226                 int changed = 0;
 227                 struct commit_list *s;
 228                 for (s = *seen_p; s; s = s->next) {
 229                         struct commit *c = s->item;
 230                         struct commit_list *parents;
 231
 232                         if (((c->object.flags & all_revs) != all_revs) &&
 233                             !(c->object.flags & UNINTERESTING))
 234                                 continue;
 235
 236                         /* The current commit is either a merge base or
 237                          * already uninteresting one.  Mark its parents
 238                          * as uninteresting commits _only_ if they are
 239                          * already parsed.  No reason to find new ones
 240                          * here.
 241                          */
 242                         parents = c->parents;
 243                         while (parents) {
 244                                 struct commit *p = parents->item;
 245                                 parents = parents->next;
 246                                 if (!(p->object.flags & UNINTERESTING)) {
 247                                         p->object.flags |= UNINTERESTING;
 248                                         changed = 1;
 249                                 }
 250                         }
 251                 }
 252                 if (!changed)
 253                         break;
 254         }
 255 }
 256
 257 static void show_one_commit(struct commit *commit, int no_name)
 258 {
 259         char pretty[256], *cp;
 260         struct commit_name *name = commit->util;
 261         if (commit->object.parsed)
 262                 pretty_print_commit(CMIT_FMT_ONELINE, commit, ~0,
 263                                     pretty, sizeof(pretty), 0, NULL, NULL);
 264         else
 265                 strcpy(pretty, "(unavailable)");
 266         if (!strncmp(pretty, "[PATCH] ", 8))
 267                 cp = pretty + 8;
 268         else
 269                 cp = pretty;
 270
 271         if (!no_name) {
 272                 if (name && name->head_name) {
 273                         printf("[%s", name->head_name);
 274                         if (name->generation) {
 275                                 if (name->generation == 1)
 276                                         printf("^");
 277                                 else
 278                                         printf("~%d", name->generation);
 279                         }
 280                         printf("] ");
 281                 }
 282                 else
 283                         printf("[%s] ",
 284                                find_unique_abbrev(commit->object.sha1, 7));
 285         }
 286         puts(cp);
 287 }
 288
 289 static char *ref_name[MAX_REVS + 1];
 290 static int ref_name_cnt;
 291
 292 static const char *find_digit_prefix(const char *s, int *v)
 293 {
 294         const char *p;
 295         int ver;
 296         char ch;
 297
 298         for (p = s, ver = 0;
 299              '0' <= (ch = *p) && ch <= '9';
 300              p++)
 301                 ver = ver * 10 + ch - '0';
 302         *v = ver;
 303         return p;
 304 }
 305
 306
 307 static int version_cmp(const char *a, const char *b)
 308 {
 309         while (1) {
 310                 int va, vb;
 311
 312                 a = find_digit_prefix(a, &va);
 313                 b = find_digit_prefix(b, &vb);
 314                 if (va != vb)
 315                         return va - vb;
 316
 317                 while (1) {
 318                         int ca = *a;
 319                         int cb = *b;
 320                         if ('0' <= ca && ca <= '9')
 321                                 ca = 0;
 322                         if ('0' <= cb && cb <= '9')
 323                                 cb = 0;
 324                         if (ca != cb)
 325                                 return ca - cb;
 326                         if (!ca)
 327                                 break;
 328                         a++;
 329                         b++;
 330                 }
 331                 if (!*a && !*b)
 332                         return 0;
 333         }
 334 }
 335
 336 static int compare_ref_name(const void *a_, const void *b_)
 337 {
 338         const char * const*a = a_, * const*b = b_;
 339         return version_cmp(*a, *b);
 340 }
 341
 342 static void sort_ref_range(int bottom, int top)
 343 {
 344         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 345               compare_ref_name);
 346 }
 347
 348 static int append_ref(const char *refname, const unsigned char *sha1)
 349 {
 350         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 351         int i;
 352
 353         if (!commit)
 354                 return 0;
 355         /* Avoid adding the same thing twice */
 356         for (i = 0; i < ref_name_cnt; i++)
 357                 if (!strcmp(refname, ref_name[i]))
 358                         return 0;
 359
 360         if (MAX_REVS <= ref_name_cnt) {
 361                 fprintf(stderr, "warning: ignoring %s; "
 362                         "cannot handle more than %d refs\n",
 363                         refname, MAX_REVS);
 364                 return 0;
 365         }
 366         ref_name[ref_name_cnt++] = strdup(refname);
 367         ref_name[ref_name_cnt] = NULL;
 368         return 0;
 369 }
 370
 371 static int append_head_ref(const char *refname, const unsigned char *sha1)
 372 {
 373         unsigned char tmp[20];
 374         int ofs = 11;
 375         if (strncmp(refname, "refs/heads/", ofs))
 376                 return 0;
 377         /* If both heads/foo and tags/foo exists, get_sha1 would
 378          * get confused.
 379          */
 380         if (get_sha1(refname + ofs, tmp) || memcmp(tmp, sha1, 20))
 381                 ofs = 5;
 382         return append_ref(refname + ofs, sha1);
 383 }
 384
 385 static int append_tag_ref(const char *refname, const unsigned char *sha1)
 386 {
 387         if (strncmp(refname, "refs/tags/", 10))
 388                 return 0;
 389         return append_ref(refname + 5, sha1);
 390 }
 391
 392 static const char *match_ref_pattern = NULL;
 393 static int match_ref_slash = 0;
 394 static int count_slash(const char *s)
 395 {
 396         int cnt = 0;
 397         while (*s)
 398                 if (*s++ == '/')
 399                         cnt++;
 400         return cnt;
 401 }
 402
 403 static int append_matching_ref(const char *refname, const unsigned char *sha1)
 404 {
 405         /* we want to allow pattern hold/<asterisk> to show all
 406          * branches under refs/heads/hold/, and v0.99.9? to show
 407          * refs/tags/v0.99.9a and friends.
 408          */
 409         const char *tail;
 410         int slash = count_slash(refname);
 411         for (tail = refname; *tail && match_ref_slash < slash; )
 412                 if (*tail++ == '/')
 413                         slash--;
 414         if (!*tail)
 415                 return 0;
 416         if (fnmatch(match_ref_pattern, tail, 0))
 417                 return 0;
 418         if (!strncmp("refs/heads/", refname, 11))
 419                 return append_head_ref(refname, sha1);
 420         if (!strncmp("refs/tags/", refname, 10))
 421                 return append_tag_ref(refname, sha1);
 422         return append_ref(refname, sha1);
 423 }
 424
 425 static void snarf_refs(int head, int tag)
 426 {
 427         if (head) {
 428                 int orig_cnt = ref_name_cnt;
 429                 for_each_ref(append_head_ref);
 430                 sort_ref_range(orig_cnt, ref_name_cnt);
 431         }
 432         if (tag) {
 433                 int orig_cnt = ref_name_cnt;
 434                 for_each_ref(append_tag_ref);
 435                 sort_ref_range(orig_cnt, ref_name_cnt);
 436         }
 437 }
 438
 439 static int rev_is_head(char *head_path, int headlen, char *name,
 440                        unsigned char *head_sha1, unsigned char *sha1)
 441 {
 442         int namelen;
 443         if ((!head_path[0]) ||
 444             (head_sha1 && sha1 && memcmp(head_sha1, sha1, 20)))
 445                 return 0;
 446         namelen = strlen(name);
 447         if ((headlen < namelen) ||
 448             memcmp(head_path + headlen - namelen, name, namelen))
 449                 return 0;
 450         if (headlen == namelen ||
 451             head_path[headlen - namelen - 1] == '/')
 452                 return 1;
 453         return 0;
 454 }
 455
 456 static int show_merge_base(struct commit_list *seen, int num_rev)
 457 {
 458         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 459         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 460         int exit_status = 1;
 461
 462         while (seen) {
 463                 struct commit *commit = pop_one_commit(&seen);
 464                 int flags = commit->object.flags & all_mask;
 465                 if (!(flags & UNINTERESTING) &&
 466                     ((flags & all_revs) == all_revs)) {
 467                         puts(sha1_to_hex(commit->object.sha1));
 468                         exit_status = 0;
 469                         commit->object.flags |= UNINTERESTING;
 470                 }
 471         }
 472         return exit_status;
 473 }
 474
 475 static int show_independent(struct commit **rev,
 476                             int num_rev,
 477                             char **ref_name,
 478                             unsigned int *rev_mask)
 479 {
 480         int i;
 481
 482         for (i = 0; i < num_rev; i++) {
 483                 struct commit *commit = rev[i];
 484                 unsigned int flag = rev_mask[i];
 485
 486                 if (commit->object.flags == flag)
 487                         puts(sha1_to_hex(commit->object.sha1));
 488                 commit->object.flags |= UNINTERESTING;
 489         }
 490         return 0;
 491 }
 492
 493 static void append_one_rev(const char *av)
 494 {
 495         unsigned char revkey[20];
 496         if (!get_sha1(av, revkey)) {
 497                 append_ref(av, revkey);
 498                 return;
 499         }
 500         if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
 501                 /* glob style match */
 502                 int saved_matches = ref_name_cnt;
 503                 match_ref_pattern = av;
 504                 match_ref_slash = count_slash(av);
 505                 for_each_ref(append_matching_ref);
 506                 if (saved_matches == ref_name_cnt &&
 507                     ref_name_cnt < MAX_REVS)
 508                         error("no matching refs with %s", av);
 509                 if (saved_matches + 1 < ref_name_cnt)
 510                         sort_ref_range(saved_matches, ref_name_cnt);
 511                 return;
 512         }
 513         die("bad sha1 reference %s", av);
 514 }
 515
 516 static int git_show_branch_config(const char *var, const char *value)
 517 {
 518         if (!strcmp(var, "showbranch.default")) {
 519                 if (default_alloc <= default_num + 1) {
 520                         default_alloc = default_alloc * 3 / 2 + 20;
 521                         default_arg = xrealloc(default_arg, sizeof *default_arg * default_alloc);
 522                 }
 523                 default_arg[default_num++] = strdup(value);
 524                 default_arg[default_num] = NULL;
 525                 return 0;
 526         }
 527
 528         return git_default_config(var, value);
 529 }
 530
 531 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
 532 {
 533         /* If the commit is tip of the named branches, do not
 534          * omit it.
 535          * Otherwise, if it is a merge that is reachable from only one
 536          * tip, it is not that interesting.
 537          */
 538         int i, flag, count;
 539         for (i = 0; i < n; i++)
 540                 if (rev[i] == commit)
 541                         return 0;
 542         flag = commit->object.flags;
 543         for (i = count = 0; i < n; i++) {
 544                 if (flag & (1u << (i + REV_SHIFT)))
 545                         count++;
 546         }
 547         if (count == 1)
 548                 return 1;
 549         return 0;
 550 }
 551
 552 int cmd_show_branch(int ac, const char **av, char **envp)
 553 {
 554         struct commit *rev[MAX_REVS], *commit;
 555         struct commit_list *list = NULL, *seen = NULL;
 556         unsigned int rev_mask[MAX_REVS];
 557         int num_rev, i, extra = 0;
 558         int all_heads = 0, all_tags = 0;
 559         int all_mask, all_revs;
 560         int lifo = 1;
 561         char head_path[128];
 562         const char *head_path_p;
 563         int head_path_len;
 564         unsigned char head_sha1[20];
 565         int merge_base = 0;
 566         int independent = 0;
 567         int no_name = 0;
 568         int sha1_name = 0;
 569         int shown_merge_point = 0;
 570         int with_current_branch = 0;
 571         int head_at = -1;
 572         int topics = 0;
 573         int dense = 1;
 574
 575         setup_git_directory();
 576         git_config(git_show_branch_config);
 577
 578         /* If nothing is specified, try the default first */
 579         if (ac == 1 && default_num) {
 580                 ac = default_num + 1;
 581                 av = default_arg - 1; /* ick; we would not address av[0] */
 582         }
 583
 584         while (1 < ac && av[1][0] == '-') {
 585                 const char *arg = av[1];
 586                 if (!strcmp(arg, "--")) {
 587                         ac--; av++;
 588                         break;
 589                 }
 590                 else if (!strcmp(arg, "--all"))
 591                         all_heads = all_tags = 1;
 592                 else if (!strcmp(arg, "--heads"))
 593                         all_heads = 1;
 594                 else if (!strcmp(arg, "--tags"))
 595                         all_tags = 1;
 596                 else if (!strcmp(arg, "--more"))
 597                         extra = 1;
 598                 else if (!strcmp(arg, "--list"))
 599                         extra = -1;
 600                 else if (!strcmp(arg, "--no-name"))
 601                         no_name = 1;
 602                 else if (!strcmp(arg, "--current"))
 603                         with_current_branch = 1;
 604                 else if (!strcmp(arg, "--sha1-name"))
 605                         sha1_name = 1;
 606                 else if (!strncmp(arg, "--more=", 7))
 607                         extra = atoi(arg + 7);
 608                 else if (!strcmp(arg, "--merge-base"))
 609                         merge_base = 1;
 610                 else if (!strcmp(arg, "--independent"))
 611                         independent = 1;
 612                 else if (!strcmp(arg, "--topo-order"))
 613                         lifo = 1;
 614                 else if (!strcmp(arg, "--topics"))
 615                         topics = 1;
 616                 else if (!strcmp(arg, "--sparse"))
 617                         dense = 0;
 618                 else if (!strcmp(arg, "--date-order"))
 619                         lifo = 0;
 620                 else
 621                         usage(show_branch_usage);
 622                 ac--; av++;
 623         }
 624         ac--; av++;
 625
 626         /* Only one of these is allowed */
 627         if (1 < independent + merge_base + (extra != 0))
 628                 usage(show_branch_usage);
 629
 630         /* If nothing is specified, show all branches by default */
 631         if (ac + all_heads + all_tags == 0)
 632                 all_heads = 1;
 633
 634         if (all_heads + all_tags)
 635                 snarf_refs(all_heads, all_tags);
 636         while (0 < ac) {
 637                 append_one_rev(*av);
 638                 ac--; av++;
 639         }
 640
 641         head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1);
 642         if (head_path_p) {
 643                 head_path_len = strlen(head_path_p);
 644                 memcpy(head_path, head_path_p, head_path_len + 1);
 645         }
 646         else {
 647                 head_path_len = 0;
 648                 head_path[0] = 0;
 649         }
 650
 651         if (with_current_branch && head_path_p) {
 652                 int has_head = 0;
 653                 for (i = 0; !has_head && i < ref_name_cnt; i++) {
 654                         /* We are only interested in adding the branch
 655                          * HEAD points at.
 656                          */
 657                         if (rev_is_head(head_path,
 658                                         head_path_len,
 659                                         ref_name[i],
 660                                         head_sha1, NULL))
 661                                 has_head++;
 662                 }
 663                 if (!has_head) {
 664                         int pfxlen = strlen(git_path("refs/heads/"));
 665                         append_one_rev(head_path + pfxlen);
 666                 }
 667         }
 668
 669         if (!ref_name_cnt) {
 670                 fprintf(stderr, "No revs to be shown.\n");
 671                 exit(0);
 672         }
 673
 674         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 675                 unsigned char revkey[20];
 676                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 677
 678                 if (MAX_REVS <= num_rev)
 679                         die("cannot handle more than %d revs.", MAX_REVS);
 680                 if (get_sha1(ref_name[num_rev], revkey))
 681                         die("'%s' is not a valid ref.", ref_name[num_rev]);
 682                 commit = lookup_commit_reference(revkey);
 683                 if (!commit)
 684                         die("cannot find commit %s (%s)",
 685                             ref_name[num_rev], revkey);
 686                 parse_commit(commit);
 687                 mark_seen(commit, &seen);
 688
 689                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 690                  * and so on.  REV_SHIFT bits from bit 0 are used for
 691                  * internal bookkeeping.
 692                  */
 693                 commit->object.flags |= flag;
 694                 if (commit->object.flags == flag)
 695                         insert_by_date(commit, &list);
 696                 rev[num_rev] = commit;
 697         }
 698         for (i = 0; i < num_rev; i++)
 699                 rev_mask[i] = rev[i]->object.flags;
 700
 701         if (0 <= extra)
 702                 join_revs(&list, &seen, num_rev, extra);
 703
 704         if (merge_base)
 705                 return show_merge_base(seen, num_rev);
 706
 707         if (independent)
 708                 return show_independent(rev, num_rev, ref_name, rev_mask);
 709
 710         /* Show list; --more=-1 means list-only */
 711         if (1 < num_rev || extra < 0) {
 712                 for (i = 0; i < num_rev; i++) {
 713                         int j;
 714                         int is_head = rev_is_head(head_path,
 715                                                   head_path_len,
 716                                                   ref_name[i],
 717                                                   head_sha1,
 718                                                   rev[i]->object.sha1);
 719                         if (extra < 0)
 720                                 printf("%c [%s] ",
 721                                        is_head ? '*' : ' ', ref_name[i]);
 722                         else {
 723                                 for (j = 0; j < i; j++)
 724                                         putchar(' ');
 725                                 printf("%c [%s] ",
 726                                        is_head ? '*' : '!', ref_name[i]);
 727                         }
 728                         /* header lines never need name */
 729                         show_one_commit(rev[i], 1);
 730                         if (is_head)
 731                                 head_at = i;
 732                 }
 733                 if (0 <= extra) {
 734                         for (i = 0; i < num_rev; i++)
 735                                 putchar('-');
 736                         putchar('\n');
 737                 }
 738         }
 739         if (extra < 0)
 740                 exit(0);
 741
 742         /* Sort topologically */
 743         sort_in_topological_order(&seen, lifo);
 744
 745         /* Give names to commits */
 746         if (!sha1_name && !no_name)
 747                 name_commits(seen, rev, ref_name, num_rev);
 748
 749         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 750         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 751
 752         while (seen) {
 753                 struct commit *commit = pop_one_commit(&seen);
 754                 int this_flag = commit->object.flags;
 755                 int is_merge_point = ((this_flag & all_revs) == all_revs);
 756
 757                 shown_merge_point |= is_merge_point;
 758
 759                 if (1 < num_rev) {
 760                         int is_merge = !!(commit->parents &&
 761                                           commit->parents->next);
 762                         if (topics &&
 763                             !is_merge_point &&
 764                             (this_flag & (1u << REV_SHIFT)))
 765                                 continue;
 766                         if (dense && is_merge &&
 767                             omit_in_dense(commit, rev, num_rev))
 768                                 continue;
 769                         for (i = 0; i < num_rev; i++) {
 770                                 int mark;
 771                                 if (!(this_flag & (1u << (i + REV_SHIFT))))
 772                                         mark = ' ';
 773                                 else if (is_merge)
 774                                         mark = '-';
 775                                 else if (i == head_at)
 776                                         mark = '*';
 777                                 else
 778                                         mark = '+';
 779                                 putchar(mark);
 780                         }
 781                         putchar(' ');
 782                 }
 783                 show_one_commit(commit, no_name);
 784
 785                 if (shown_merge_point && --extra < 0)
 786                         break;
 787         }
 788         return 0;
 789 }