builtin/show-branch.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "refs.h"
   4 #include "builtin.h"
   5 #include "color.h"
   6 #include "parse-options.h"
   7
   8 static const char* show_branch_usage[] = {
   9     N_("git show-branch [-a|--all] [-r|--remotes] [--topo-order | --date-order] [--current] [--color[=<when>] | --no-color] [--sparse] [--more=<n> | --list | --independent | --merge-base] [--no-name | --sha1-name] [--topics] [(<rev> | <glob>)...]"),
  10     N_("git show-branch (-g|--reflog)[=<n>[,<base>]] [--list] [<ref>]"),
  11     NULL
  12 };
  13
  14 static int showbranch_use_color = -1;
  15
  16 static int default_num;
  17 static int default_alloc;
  18 static const char **default_arg;
  19
  20 #define UNINTERESTING   01
  21
  22 #define REV_SHIFT        2
  23 #define MAX_REVS        (FLAG_BITS - REV_SHIFT) /* should not exceed bits_per_int - REV_SHIFT */
  24
  25 #define DEFAULT_REFLOG  4
  26
  27 static const char *get_color_code(int idx)
  28 {
  29         if (want_color(showbranch_use_color))
  30                 return column_colors_ansi[idx % column_colors_ansi_max];
  31         return "";
  32 }
  33
  34 static const char *get_color_reset_code(void)
  35 {
  36         if (want_color(showbranch_use_color))
  37                 return GIT_COLOR_RESET;
  38         return "";
  39 }
  40
  41 static struct commit *interesting(struct commit_list *list)
  42 {
  43         while (list) {
  44                 struct commit *commit = list->item;
  45                 list = list->next;
  46                 if (commit->object.flags & UNINTERESTING)
  47                         continue;
  48                 return commit;
  49         }
  50         return NULL;
  51 }
  52
  53 static struct commit *pop_one_commit(struct commit_list **list_p)
  54 {
  55         struct commit *commit;
  56         struct commit_list *list;
  57         list = *list_p;
  58         commit = list->item;
  59         *list_p = list->next;
  60         free(list);
  61         return commit;
  62 }
  63
  64 struct commit_name {
  65         const char *head_name; /* which head's ancestor? */
  66         int generation; /* how many parents away from head_name */
  67 };
  68
  69 /* Name the commit as nth generation ancestor of head_name;
  70  * we count only the first-parent relationship for naming purposes.
  71  */
  72 static void name_commit(struct commit *commit, const char *head_name, int nth)
  73 {
  74         struct commit_name *name;
  75         if (!commit->util)
  76                 commit->util = xmalloc(sizeof(struct commit_name));
  77         name = commit->util;
  78         name->head_name = head_name;
  79         name->generation = nth;
  80 }
  81
  82 /* Parent is the first parent of the commit.  We may name it
  83  * as (n+1)th generation ancestor of the same head_name as
  84  * commit is nth generation ancestor of, if that generation
  85  * number is better than the name it already has.
  86  */
  87 static void name_parent(struct commit *commit, struct commit *parent)
  88 {
  89         struct commit_name *commit_name = commit->util;
  90         struct commit_name *parent_name = parent->util;
  91         if (!commit_name)
  92                 return;
  93         if (!parent_name ||
  94             commit_name->generation + 1 < parent_name->generation)
  95                 name_commit(parent, commit_name->head_name,
  96                             commit_name->generation + 1);
  97 }
  98
  99 static int name_first_parent_chain(struct commit *c)
 100 {
 101         int i = 0;
 102         while (c) {
 103                 struct commit *p;
 104                 if (!c->util)
 105                         break;
 106                 if (!c->parents)
 107                         break;
 108                 p = c->parents->item;
 109                 if (!p->util) {
 110                         name_parent(c, p);
 111                         i++;
 112                 }
 113                 else
 114                         break;
 115                 c = p;
 116         }
 117         return i;
 118 }
 119
 120 static void name_commits(struct commit_list *list,
 121                          struct commit **rev,
 122                          char **ref_name,
 123                          int num_rev)
 124 {
 125         struct commit_list *cl;
 126         struct commit *c;
 127         int i;
 128
 129         /* First give names to the given heads */
 130         for (cl = list; cl; cl = cl->next) {
 131                 c = cl->item;
 132                 if (c->util)
 133                         continue;
 134                 for (i = 0; i < num_rev; i++) {
 135                         if (rev[i] == c) {
 136                                 name_commit(c, ref_name[i], 0);
 137                                 break;
 138                         }
 139                 }
 140         }
 141
 142         /* Then commits on the first parent ancestry chain */
 143         do {
 144                 i = 0;
 145                 for (cl = list; cl; cl = cl->next) {
 146                         i += name_first_parent_chain(cl->item);
 147                 }
 148         } while (i);
 149
 150         /* Finally, any unnamed commits */
 151         do {
 152                 i = 0;
 153                 for (cl = list; cl; cl = cl->next) {
 154                         struct commit_list *parents;
 155                         struct commit_name *n;
 156                         int nth;
 157                         c = cl->item;
 158                         if (!c->util)
 159                                 continue;
 160                         n = c->util;
 161                         parents = c->parents;
 162                         nth = 0;
 163                         while (parents) {
 164                                 struct commit *p = parents->item;
 165                                 struct strbuf newname = STRBUF_INIT;
 166                                 parents = parents->next;
 167                                 nth++;
 168                                 if (p->util)
 169                                         continue;
 170                                 switch (n->generation) {
 171                                 case 0:
 172                                         strbuf_addstr(&newname, n->head_name);
 173                                         break;
 174                                 case 1:
 175                                         strbuf_addf(&newname, "%s^", n->head_name);
 176                                         break;
 177                                 default:
 178                                         strbuf_addf(&newname, "%s~%d",
 179                                                     n->head_name, n->generation);
 180                                         break;
 181                                 }
 182                                 if (nth == 1)
 183                                         strbuf_addch(&newname, '^');
 184                                 else
 185                                         strbuf_addf(&newname, "^%d", nth);
 186                                 name_commit(p, strbuf_detach(&newname, NULL), 0);
 187                                 i++;
 188                                 name_first_parent_chain(p);
 189                         }
 190                 }
 191         } while (i);
 192 }
 193
 194 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 195 {
 196         if (!commit->object.flags) {
 197                 commit_list_insert(commit, seen_p);
 198                 return 1;
 199         }
 200         return 0;
 201 }
 202
 203 static void join_revs(struct commit_list **list_p,
 204                       struct commit_list **seen_p,
 205                       int num_rev, int extra)
 206 {
 207         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 208         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 209
 210         while (*list_p) {
 211                 struct commit_list *parents;
 212                 int still_interesting = !!interesting(*list_p);
 213                 struct commit *commit = pop_one_commit(list_p);
 214                 int flags = commit->object.flags & all_mask;
 215
 216                 if (!still_interesting && extra <= 0)
 217                         break;
 218
 219                 mark_seen(commit, seen_p);
 220                 if ((flags & all_revs) == all_revs)
 221                         flags |= UNINTERESTING;
 222                 parents = commit->parents;
 223
 224                 while (parents) {
 225                         struct commit *p = parents->item;
 226                         int this_flag = p->object.flags;
 227                         parents = parents->next;
 228                         if ((this_flag & flags) == flags)
 229                                 continue;
 230                         if (!p->object.parsed)
 231                                 parse_commit(p);
 232                         if (mark_seen(p, seen_p) && !still_interesting)
 233                                 extra--;
 234                         p->object.flags |= flags;
 235                         commit_list_insert_by_date(p, list_p);
 236                 }
 237         }
 238
 239         /*
 240          * Postprocess to complete well-poisoning.
 241          *
 242          * At this point we have all the commits we have seen in
 243          * seen_p list.  Mark anything that can be reached from
 244          * uninteresting commits not interesting.
 245          */
 246         for (;;) {
 247                 int changed = 0;
 248                 struct commit_list *s;
 249                 for (s = *seen_p; s; s = s->next) {
 250                         struct commit *c = s->item;
 251                         struct commit_list *parents;
 252
 253                         if (((c->object.flags & all_revs) != all_revs) &&
 254                             !(c->object.flags & UNINTERESTING))
 255                                 continue;
 256
 257                         /* The current commit is either a merge base or
 258                          * already uninteresting one.  Mark its parents
 259                          * as uninteresting commits _only_ if they are
 260                          * already parsed.  No reason to find new ones
 261                          * here.
 262                          */
 263                         parents = c->parents;
 264                         while (parents) {
 265                                 struct commit *p = parents->item;
 266                                 parents = parents->next;
 267                                 if (!(p->object.flags & UNINTERESTING)) {
 268                                         p->object.flags |= UNINTERESTING;
 269                                         changed = 1;
 270                                 }
 271                         }
 272                 }
 273                 if (!changed)
 274                         break;
 275         }
 276 }
 277
 278 static void show_one_commit(struct commit *commit, int no_name)
 279 {
 280         struct strbuf pretty = STRBUF_INIT;
 281         const char *pretty_str = "(unavailable)";
 282         struct commit_name *name = commit->util;
 283
 284         if (commit->object.parsed) {
 285                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &pretty);
 286                 pretty_str = pretty.buf;
 287         }
 288         if (!prefixcmp(pretty_str, "[PATCH] "))
 289                 pretty_str += 8;
 290
 291         if (!no_name) {
 292                 if (name && name->head_name) {
 293                         printf("[%s", name->head_name);
 294                         if (name->generation) {
 295                                 if (name->generation == 1)
 296                                         printf("^");
 297                                 else
 298                                         printf("~%d", name->generation);
 299                         }
 300                         printf("] ");
 301                 }
 302                 else
 303                         printf("[%s] ",
 304                                find_unique_abbrev(commit->object.sha1,
 305                                                   DEFAULT_ABBREV));
 306         }
 307         puts(pretty_str);
 308         strbuf_release(&pretty);
 309 }
 310
 311 static char *ref_name[MAX_REVS + 1];
 312 static int ref_name_cnt;
 313
 314 static const char *find_digit_prefix(const char *s, int *v)
 315 {
 316         const char *p;
 317         int ver;
 318         char ch;
 319
 320         for (p = s, ver = 0;
 321              '0' <= (ch = *p) && ch <= '9';
 322              p++)
 323                 ver = ver * 10 + ch - '0';
 324         *v = ver;
 325         return p;
 326 }
 327
 328
 329 static int version_cmp(const char *a, const char *b)
 330 {
 331         while (1) {
 332                 int va, vb;
 333
 334                 a = find_digit_prefix(a, &va);
 335                 b = find_digit_prefix(b, &vb);
 336                 if (va != vb)
 337                         return va - vb;
 338
 339                 while (1) {
 340                         int ca = *a;
 341                         int cb = *b;
 342                         if ('0' <= ca && ca <= '9')
 343                                 ca = 0;
 344                         if ('0' <= cb && cb <= '9')
 345                                 cb = 0;
 346                         if (ca != cb)
 347                                 return ca - cb;
 348                         if (!ca)
 349                                 break;
 350                         a++;
 351                         b++;
 352                 }
 353                 if (!*a && !*b)
 354                         return 0;
 355         }
 356 }
 357
 358 static int compare_ref_name(const void *a_, const void *b_)
 359 {
 360         const char * const*a = a_, * const*b = b_;
 361         return version_cmp(*a, *b);
 362 }
 363
 364 static void sort_ref_range(int bottom, int top)
 365 {
 366         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 367               compare_ref_name);
 368 }
 369
 370 static int append_ref(const char *refname, const unsigned char *sha1,
 371                       int allow_dups)
 372 {
 373         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 374         int i;
 375
 376         if (!commit)
 377                 return 0;
 378
 379         if (!allow_dups) {
 380                 /* Avoid adding the same thing twice */
 381                 for (i = 0; i < ref_name_cnt; i++)
 382                         if (!strcmp(refname, ref_name[i]))
 383                                 return 0;
 384         }
 385         if (MAX_REVS <= ref_name_cnt) {
 386                 warning("ignoring %s; cannot handle more than %d refs",
 387                         refname, MAX_REVS);
 388                 return 0;
 389         }
 390         ref_name[ref_name_cnt++] = xstrdup(refname);
 391         ref_name[ref_name_cnt] = NULL;
 392         return 0;
 393 }
 394
 395 static int append_head_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 396 {
 397         unsigned char tmp[20];
 398         int ofs = 11;
 399         if (prefixcmp(refname, "refs/heads/"))
 400                 return 0;
 401         /* If both heads/foo and tags/foo exists, get_sha1 would
 402          * get confused.
 403          */
 404         if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
 405                 ofs = 5;
 406         return append_ref(refname + ofs, sha1, 0);
 407 }
 408
 409 static int append_remote_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 410 {
 411         unsigned char tmp[20];
 412         int ofs = 13;
 413         if (prefixcmp(refname, "refs/remotes/"))
 414                 return 0;
 415         /* If both heads/foo and tags/foo exists, get_sha1 would
 416          * get confused.
 417          */
 418         if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
 419                 ofs = 5;
 420         return append_ref(refname + ofs, sha1, 0);
 421 }
 422
 423 static int append_tag_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 424 {
 425         if (prefixcmp(refname, "refs/tags/"))
 426                 return 0;
 427         return append_ref(refname + 5, sha1, 0);
 428 }
 429
 430 static const char *match_ref_pattern = NULL;
 431 static int match_ref_slash = 0;
 432 static int count_slash(const char *s)
 433 {
 434         int cnt = 0;
 435         while (*s)
 436                 if (*s++ == '/')
 437                         cnt++;
 438         return cnt;
 439 }
 440
 441 static int append_matching_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 442 {
 443         /* we want to allow pattern hold/<asterisk> to show all
 444          * branches under refs/heads/hold/, and v0.99.9? to show
 445          * refs/tags/v0.99.9a and friends.
 446          */
 447         const char *tail;
 448         int slash = count_slash(refname);
 449         for (tail = refname; *tail && match_ref_slash < slash; )
 450                 if (*tail++ == '/')
 451                         slash--;
 452         if (!*tail)
 453                 return 0;
 454         if (fnmatch(match_ref_pattern, tail, 0))
 455                 return 0;
 456         if (!prefixcmp(refname, "refs/heads/"))
 457                 return append_head_ref(refname, sha1, flag, cb_data);
 458         if (!prefixcmp(refname, "refs/tags/"))
 459                 return append_tag_ref(refname, sha1, flag, cb_data);
 460         return append_ref(refname, sha1, 0);
 461 }
 462
 463 static void snarf_refs(int head, int remotes)
 464 {
 465         if (head) {
 466                 int orig_cnt = ref_name_cnt;
 467                 for_each_ref(append_head_ref, NULL);
 468                 sort_ref_range(orig_cnt, ref_name_cnt);
 469         }
 470         if (remotes) {
 471                 int orig_cnt = ref_name_cnt;
 472                 for_each_ref(append_remote_ref, NULL);
 473                 sort_ref_range(orig_cnt, ref_name_cnt);
 474         }
 475 }
 476
 477 static int rev_is_head(char *head, int headlen, char *name,
 478                        unsigned char *head_sha1, unsigned char *sha1)
 479 {
 480         if ((!head[0]) ||
 481             (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
 482                 return 0;
 483         if (!prefixcmp(head, "refs/heads/"))
 484                 head += 11;
 485         if (!prefixcmp(name, "refs/heads/"))
 486                 name += 11;
 487         else if (!prefixcmp(name, "heads/"))
 488                 name += 6;
 489         return !strcmp(head, name);
 490 }
 491
 492 static int show_merge_base(struct commit_list *seen, int num_rev)
 493 {
 494         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 495         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 496         int exit_status = 1;
 497
 498         while (seen) {
 499                 struct commit *commit = pop_one_commit(&seen);
 500                 int flags = commit->object.flags & all_mask;
 501                 if (!(flags & UNINTERESTING) &&
 502                     ((flags & all_revs) == all_revs)) {
 503                         puts(sha1_to_hex(commit->object.sha1));
 504                         exit_status = 0;
 505                         commit->object.flags |= UNINTERESTING;
 506                 }
 507         }
 508         return exit_status;
 509 }
 510
 511 static int show_independent(struct commit **rev,
 512                             int num_rev,
 513                             char **ref_name,
 514                             unsigned int *rev_mask)
 515 {
 516         int i;
 517
 518         for (i = 0; i < num_rev; i++) {
 519                 struct commit *commit = rev[i];
 520                 unsigned int flag = rev_mask[i];
 521
 522                 if (commit->object.flags == flag)
 523                         puts(sha1_to_hex(commit->object.sha1));
 524                 commit->object.flags |= UNINTERESTING;
 525         }
 526         return 0;
 527 }
 528
 529 static void append_one_rev(const char *av)
 530 {
 531         unsigned char revkey[20];
 532         if (!get_sha1(av, revkey)) {
 533                 append_ref(av, revkey, 0);
 534                 return;
 535         }
 536         if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
 537                 /* glob style match */
 538                 int saved_matches = ref_name_cnt;
 539                 match_ref_pattern = av;
 540                 match_ref_slash = count_slash(av);
 541                 for_each_ref(append_matching_ref, NULL);
 542                 if (saved_matches == ref_name_cnt &&
 543                     ref_name_cnt < MAX_REVS)
 544                         error("no matching refs with %s", av);
 545                 if (saved_matches + 1 < ref_name_cnt)
 546                         sort_ref_range(saved_matches, ref_name_cnt);
 547                 return;
 548         }
 549         die("bad sha1 reference %s", av);
 550 }
 551
 552 static int git_show_branch_config(const char *var, const char *value, void *cb)
 553 {
 554         if (!strcmp(var, "showbranch.default")) {
 555                 if (!value)
 556                         return config_error_nonbool(var);
 557                 /*
 558                  * default_arg is now passed to parse_options(), so we need to
 559                  * mimic the real argv a bit better.
 560                  */
 561                 if (!default_num) {
 562                         default_alloc = 20;
 563                         default_arg = xcalloc(default_alloc, sizeof(*default_arg));
 564                         default_arg[default_num++] = "show-branch";
 565                 } else if (default_alloc <= default_num + 1) {
 566                         default_alloc = default_alloc * 3 / 2 + 20;
 567                         default_arg = xrealloc(default_arg, sizeof *default_arg * default_alloc);
 568                 }
 569                 default_arg[default_num++] = xstrdup(value);
 570                 default_arg[default_num] = NULL;
 571                 return 0;
 572         }
 573
 574         if (!strcmp(var, "color.showbranch")) {
 575                 showbranch_use_color = git_config_colorbool(var, value);
 576                 return 0;
 577         }
 578
 579         return git_color_default_config(var, value, cb);
 580 }
 581
 582 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
 583 {
 584         /* If the commit is tip of the named branches, do not
 585          * omit it.
 586          * Otherwise, if it is a merge that is reachable from only one
 587          * tip, it is not that interesting.
 588          */
 589         int i, flag, count;
 590         for (i = 0; i < n; i++)
 591                 if (rev[i] == commit)
 592                         return 0;
 593         flag = commit->object.flags;
 594         for (i = count = 0; i < n; i++) {
 595                 if (flag & (1u << (i + REV_SHIFT)))
 596                         count++;
 597         }
 598         if (count == 1)
 599                 return 1;
 600         return 0;
 601 }
 602
 603 static int reflog = 0;
 604
 605 static int parse_reflog_param(const struct option *opt, const char *arg,
 606                               int unset)
 607 {
 608         char *ep;
 609         const char **base = (const char **)opt->value;
 610         if (!arg)
 611                 arg = "";
 612         reflog = strtoul(arg, &ep, 10);
 613         if (*ep == ',')
 614                 *base = ep + 1;
 615         else if (*ep)
 616                 return error("unrecognized reflog param '%s'", arg);
 617         else
 618                 *base = NULL;
 619         if (reflog <= 0)
 620                 reflog = DEFAULT_REFLOG;
 621         return 0;
 622 }
 623
 624 int cmd_show_branch(int ac, const char **av, const char *prefix)
 625 {
 626         struct commit *rev[MAX_REVS], *commit;
 627         char *reflog_msg[MAX_REVS];
 628         struct commit_list *list = NULL, *seen = NULL;
 629         unsigned int rev_mask[MAX_REVS];
 630         int num_rev, i, extra = 0;
 631         int all_heads = 0, all_remotes = 0;
 632         int all_mask, all_revs;
 633         enum rev_sort_order sort_order = REV_SORT_IN_GRAPH_ORDER;
 634         char head[128];
 635         const char *head_p;
 636         int head_len;
 637         unsigned char head_sha1[20];
 638         int merge_base = 0;
 639         int independent = 0;
 640         int no_name = 0;
 641         int sha1_name = 0;
 642         int shown_merge_point = 0;
 643         int with_current_branch = 0;
 644         int head_at = -1;
 645         int topics = 0;
 646         int dense = 1;
 647         const char *reflog_base = NULL;
 648         struct option builtin_show_branch_options[] = {
 649                 OPT_BOOLEAN('a', "all", &all_heads,
 650                             N_("show remote-tracking and local branches")),
 651                 OPT_BOOLEAN('r', "remotes", &all_remotes,
 652                             N_("show remote-tracking branches")),
 653                 OPT__COLOR(&showbranch_use_color,
 654                             N_("color '*!+-' corresponding to the branch")),
 655                 { OPTION_INTEGER, 0, "more", &extra, N_("n"),
 656                             N_("show <n> more commits after the common ancestor"),
 657                             PARSE_OPT_OPTARG, NULL, (intptr_t)1 },
 658                 OPT_SET_INT(0, "list", &extra, N_("synonym to more=-1"), -1),
 659                 OPT_BOOLEAN(0, "no-name", &no_name, N_("suppress naming strings")),
 660                 OPT_BOOLEAN(0, "current", &with_current_branch,
 661                             N_("include the current branch")),
 662                 OPT_BOOLEAN(0, "sha1-name", &sha1_name,
 663                             N_("name commits with their object names")),
 664                 OPT_BOOLEAN(0, "merge-base", &merge_base,
 665                             N_("show possible merge bases")),
 666                 OPT_BOOLEAN(0, "independent", &independent,
 667                             N_("show refs unreachable from any other ref")),
 668                 OPT_SET_INT(0, "topo-order", &sort_order,
 669                             N_("show commits in topological order"),
 670                             REV_SORT_IN_GRAPH_ORDER),
 671                 OPT_BOOLEAN(0, "topics", &topics,
 672                             N_("show only commits not on the first branch")),
 673                 OPT_SET_INT(0, "sparse", &dense,
 674                             N_("show merges reachable from only one tip"), 0),
 675                 OPT_SET_INT(0, "date-order", &sort_order,
 676                             N_("topologically sort, maintaining date order "
 677                                "where possible"),
 678                             REV_SORT_BY_COMMIT_DATE),
 679                 { OPTION_CALLBACK, 'g', "reflog", &reflog_base, N_("<n>[,<base>]"),
 680                             N_("show <n> most recent ref-log entries starting at "
 681                                "base"),
 682                             PARSE_OPT_OPTARG | PARSE_OPT_LITERAL_ARGHELP,
 683                             parse_reflog_param },
 684                 OPT_END()
 685         };
 686
 687         git_config(git_show_branch_config, NULL);
 688
 689         /* If nothing is specified, try the default first */
 690         if (ac == 1 && default_num) {
 691                 ac = default_num;
 692                 av = default_arg;
 693         }
 694
 695         ac = parse_options(ac, av, prefix, builtin_show_branch_options,
 696                            show_branch_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 697         if (all_heads)
 698                 all_remotes = 1;
 699
 700         if (extra || reflog) {
 701                 /* "listing" mode is incompatible with
 702                  * independent nor merge-base modes.
 703                  */
 704                 if (independent || merge_base)
 705                         usage_with_options(show_branch_usage,
 706                                            builtin_show_branch_options);
 707                 if (reflog && ((0 < extra) || all_heads || all_remotes))
 708                         /*
 709                          * Asking for --more in reflog mode does not
 710                          * make sense.  --list is Ok.
 711                          *
 712                          * Also --all and --remotes do not make sense either.
 713                          */
 714                         die("--reflog is incompatible with --all, --remotes, "
 715                             "--independent or --merge-base");
 716         }
 717
 718         /* If nothing is specified, show all branches by default */
 719         if (ac + all_heads + all_remotes == 0)
 720                 all_heads = 1;
 721
 722         if (reflog) {
 723                 unsigned char sha1[20];
 724                 char nth_desc[256];
 725                 char *ref;
 726                 int base = 0;
 727
 728                 if (ac == 0) {
 729                         static const char *fake_av[2];
 730
 731                         fake_av[0] = resolve_refdup("HEAD", sha1, 1, NULL);
 732                         fake_av[1] = NULL;
 733                         av = fake_av;
 734                         ac = 1;
 735                 }
 736                 if (ac != 1)
 737                         die("--reflog option needs one branch name");
 738
 739                 if (MAX_REVS < reflog)
 740                         die("Only %d entries can be shown at one time.",
 741                             MAX_REVS);
 742                 if (!dwim_ref(*av, strlen(*av), sha1, &ref))
 743                         die("No such ref %s", *av);
 744
 745                 /* Has the base been specified? */
 746                 if (reflog_base) {
 747                         char *ep;
 748                         base = strtoul(reflog_base, &ep, 10);
 749                         if (*ep) {
 750                                 /* Ah, that is a date spec... */
 751                                 unsigned long at;
 752                                 at = approxidate(reflog_base);
 753                                 read_ref_at(ref, at, -1, sha1, NULL,
 754                                             NULL, NULL, &base);
 755                         }
 756                 }
 757
 758                 for (i = 0; i < reflog; i++) {
 759                         char *logmsg, *m;
 760                         const char *msg;
 761                         unsigned long timestamp;
 762                         int tz;
 763
 764                         if (read_ref_at(ref, 0, base+i, sha1, &logmsg,
 765                                         &timestamp, &tz, NULL)) {
 766                                 reflog = i;
 767                                 break;
 768                         }
 769                         msg = strchr(logmsg, '\t');
 770                         if (!msg)
 771                                 msg = "(none)";
 772                         else
 773                                 msg++;
 774                         m = xmalloc(strlen(msg) + 200);
 775                         sprintf(m, "(%s) %s",
 776                                 show_date(timestamp, tz, 1),
 777                                 msg);
 778                         reflog_msg[i] = m;
 779                         free(logmsg);
 780                         sprintf(nth_desc, "%s@{%d}", *av, base+i);
 781                         append_ref(nth_desc, sha1, 1);
 782                 }
 783         }
 784         else if (all_heads + all_remotes)
 785                 snarf_refs(all_heads, all_remotes);
 786         else {
 787                 while (0 < ac) {
 788                         append_one_rev(*av);
 789                         ac--; av++;
 790                 }
 791         }
 792
 793         head_p = resolve_ref_unsafe("HEAD", head_sha1, 1, NULL);
 794         if (head_p) {
 795                 head_len = strlen(head_p);
 796                 memcpy(head, head_p, head_len + 1);
 797         }
 798         else {
 799                 head_len = 0;
 800                 head[0] = 0;
 801         }
 802
 803         if (with_current_branch && head_p) {
 804                 int has_head = 0;
 805                 for (i = 0; !has_head && i < ref_name_cnt; i++) {
 806                         /* We are only interested in adding the branch
 807                          * HEAD points at.
 808                          */
 809                         if (rev_is_head(head,
 810                                         head_len,
 811                                         ref_name[i],
 812                                         head_sha1, NULL))
 813                                 has_head++;
 814                 }
 815                 if (!has_head) {
 816                         int offset = !prefixcmp(head, "refs/heads/") ? 11 : 0;
 817                         append_one_rev(head + offset);
 818                 }
 819         }
 820
 821         if (!ref_name_cnt) {
 822                 fprintf(stderr, "No revs to be shown.\n");
 823                 exit(0);
 824         }
 825
 826         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 827                 unsigned char revkey[20];
 828                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 829
 830                 if (MAX_REVS <= num_rev)
 831                         die("cannot handle more than %d revs.", MAX_REVS);
 832                 if (get_sha1(ref_name[num_rev], revkey))
 833                         die("'%s' is not a valid ref.", ref_name[num_rev]);
 834                 commit = lookup_commit_reference(revkey);
 835                 if (!commit)
 836                         die("cannot find commit %s (%s)",
 837                             ref_name[num_rev], revkey);
 838                 parse_commit(commit);
 839                 mark_seen(commit, &seen);
 840
 841                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 842                  * and so on.  REV_SHIFT bits from bit 0 are used for
 843                  * internal bookkeeping.
 844                  */
 845                 commit->object.flags |= flag;
 846                 if (commit->object.flags == flag)
 847                         commit_list_insert_by_date(commit, &list);
 848                 rev[num_rev] = commit;
 849         }
 850         for (i = 0; i < num_rev; i++)
 851                 rev_mask[i] = rev[i]->object.flags;
 852
 853         if (0 <= extra)
 854                 join_revs(&list, &seen, num_rev, extra);
 855
 856         commit_list_sort_by_date(&seen);
 857
 858         if (merge_base)
 859                 return show_merge_base(seen, num_rev);
 860
 861         if (independent)
 862                 return show_independent(rev, num_rev, ref_name, rev_mask);
 863
 864         /* Show list; --more=-1 means list-only */
 865         if (1 < num_rev || extra < 0) {
 866                 for (i = 0; i < num_rev; i++) {
 867                         int j;
 868                         int is_head = rev_is_head(head,
 869                                                   head_len,
 870                                                   ref_name[i],
 871                                                   head_sha1,
 872                                                   rev[i]->object.sha1);
 873                         if (extra < 0)
 874                                 printf("%c [%s] ",
 875                                        is_head ? '*' : ' ', ref_name[i]);
 876                         else {
 877                                 for (j = 0; j < i; j++)
 878                                         putchar(' ');
 879                                 printf("%s%c%s [%s] ",
 880                                        get_color_code(i),
 881                                        is_head ? '*' : '!',
 882                                        get_color_reset_code(), ref_name[i]);
 883                         }
 884
 885                         if (!reflog) {
 886                                 /* header lines never need name */
 887                                 show_one_commit(rev[i], 1);
 888                         }
 889                         else
 890                                 puts(reflog_msg[i]);
 891
 892                         if (is_head)
 893                                 head_at = i;
 894                 }
 895                 if (0 <= extra) {
 896                         for (i = 0; i < num_rev; i++)
 897                                 putchar('-');
 898                         putchar('\n');
 899                 }
 900         }
 901         if (extra < 0)
 902                 exit(0);
 903
 904         /* Sort topologically */
 905         sort_in_topological_order(&seen, sort_order);
 906
 907         /* Give names to commits */
 908         if (!sha1_name && !no_name)
 909                 name_commits(seen, rev, ref_name, num_rev);
 910
 911         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 912         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 913
 914         while (seen) {
 915                 struct commit *commit = pop_one_commit(&seen);
 916                 int this_flag = commit->object.flags;
 917                 int is_merge_point = ((this_flag & all_revs) == all_revs);
 918
 919                 shown_merge_point |= is_merge_point;
 920
 921                 if (1 < num_rev) {
 922                         int is_merge = !!(commit->parents &&
 923                                           commit->parents->next);
 924                         if (topics &&
 925                             !is_merge_point &&
 926                             (this_flag & (1u << REV_SHIFT)))
 927                                 continue;
 928                         if (dense && is_merge &&
 929                             omit_in_dense(commit, rev, num_rev))
 930                                 continue;
 931                         for (i = 0; i < num_rev; i++) {
 932                                 int mark;
 933                                 if (!(this_flag & (1u << (i + REV_SHIFT))))
 934                                         mark = ' ';
 935                                 else if (is_merge)
 936                                         mark = '-';
 937                                 else if (i == head_at)
 938                                         mark = '*';
 939                                 else
 940                                         mark = '+';
 941                                 printf("%s%c%s",
 942                                        get_color_code(i),
 943                                        mark, get_color_reset_code());
 944                         }
 945                         putchar(' ');
 946                 }
 947                 show_one_commit(commit, no_name);
 948
 949                 if (shown_merge_point && --extra < 0)
 950                         break;
 951         }
 952         return 0;
 953 }