git.oblomov.eu Git - git/blob - 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]\n"
  10        "                [--current] [--color[=<when>] | --no-color] [--sparse]\n"
  11        "                [--more=<n> | --list | --independent | --merge-base]\n"
  12        "                [--no-name | --sha1-name] [--topics] [(<rev> | <glob>)...]"),
  13     N_("git show-branch (-g | --reflog)[=<n>[,<base>]] [--list] [<ref>]"),
  14     NULL
  15 };
  16
  17 static int showbranch_use_color = -1;
  18
  19 static int default_num;
  20 static int default_alloc;
  21 static const char **default_arg;
  22
  23 #define UNINTERESTING   01
  24
  25 #define REV_SHIFT        2
  26 #define MAX_REVS        (FLAG_BITS - REV_SHIFT) /* should not exceed bits_per_int - REV_SHIFT */
  27
  28 #define DEFAULT_REFLOG  4
  29
  30 static const char *get_color_code(int idx)
  31 {
  32         if (want_color(showbranch_use_color))
  33                 return column_colors_ansi[idx % column_colors_ansi_max];
  34         return "";
  35 }
  36
  37 static const char *get_color_reset_code(void)
  38 {
  39         if (want_color(showbranch_use_color))
  40                 return GIT_COLOR_RESET;
  41         return "";
  42 }
  43
  44 static struct commit *interesting(struct commit_list *list)
  45 {
  46         while (list) {
  47                 struct commit *commit = list->item;
  48                 list = list->next;
  49                 if (commit->object.flags & UNINTERESTING)
  50                         continue;
  51                 return commit;
  52         }
  53         return NULL;
  54 }
  55
  56 static struct commit *pop_one_commit(struct commit_list **list_p)
  57 {
  58         struct commit *commit;
  59         struct commit_list *list;
  60         list = *list_p;
  61         commit = list->item;
  62         *list_p = list->next;
  63         free(list);
  64         return commit;
  65 }
  66
  67 struct commit_name {
  68         const char *head_name; /* which head's ancestor? */
  69         int generation; /* how many parents away from head_name */
  70 };
  71
  72 /* Name the commit as nth generation ancestor of head_name;
  73  * we count only the first-parent relationship for naming purposes.
  74  */
  75 static void name_commit(struct commit *commit, const char *head_name, int nth)
  76 {
  77         struct commit_name *name;
  78         if (!commit->util)
  79                 commit->util = xmalloc(sizeof(struct commit_name));
  80         name = commit->util;
  81         name->head_name = head_name;
  82         name->generation = nth;
  83 }
  84
  85 /* Parent is the first parent of the commit.  We may name it
  86  * as (n+1)th generation ancestor of the same head_name as
  87  * commit is nth generation ancestor of, if that generation
  88  * number is better than the name it already has.
  89  */
  90 static void name_parent(struct commit *commit, struct commit *parent)
  91 {
  92         struct commit_name *commit_name = commit->util;
  93         struct commit_name *parent_name = parent->util;
  94         if (!commit_name)
  95                 return;
  96         if (!parent_name ||
  97             commit_name->generation + 1 < parent_name->generation)
  98                 name_commit(parent, commit_name->head_name,
  99                             commit_name->generation + 1);
 100 }
 101
 102 static int name_first_parent_chain(struct commit *c)
 103 {
 104         int i = 0;
 105         while (c) {
 106                 struct commit *p;
 107                 if (!c->util)
 108                         break;
 109                 if (!c->parents)
 110                         break;
 111                 p = c->parents->item;
 112                 if (!p->util) {
 113                         name_parent(c, p);
 114                         i++;
 115                 }
 116                 else
 117                         break;
 118                 c = p;
 119         }
 120         return i;
 121 }
 122
 123 static void name_commits(struct commit_list *list,
 124                          struct commit **rev,
 125                          char **ref_name,
 126                          int num_rev)
 127 {
 128         struct commit_list *cl;
 129         struct commit *c;
 130         int i;
 131
 132         /* First give names to the given heads */
 133         for (cl = list; cl; cl = cl->next) {
 134                 c = cl->item;
 135                 if (c->util)
 136                         continue;
 137                 for (i = 0; i < num_rev; i++) {
 138                         if (rev[i] == c) {
 139                                 name_commit(c, ref_name[i], 0);
 140                                 break;
 141                         }
 142                 }
 143         }
 144
 145         /* Then commits on the first parent ancestry chain */
 146         do {
 147                 i = 0;
 148                 for (cl = list; cl; cl = cl->next) {
 149                         i += name_first_parent_chain(cl->item);
 150                 }
 151         } while (i);
 152
 153         /* Finally, any unnamed commits */
 154         do {
 155                 i = 0;
 156                 for (cl = list; cl; cl = cl->next) {
 157                         struct commit_list *parents;
 158                         struct commit_name *n;
 159                         int nth;
 160                         c = cl->item;
 161                         if (!c->util)
 162                                 continue;
 163                         n = c->util;
 164                         parents = c->parents;
 165                         nth = 0;
 166                         while (parents) {
 167                                 struct commit *p = parents->item;
 168                                 struct strbuf newname = STRBUF_INIT;
 169                                 parents = parents->next;
 170                                 nth++;
 171                                 if (p->util)
 172                                         continue;
 173                                 switch (n->generation) {
 174                                 case 0:
 175                                         strbuf_addstr(&newname, n->head_name);
 176                                         break;
 177                                 case 1:
 178                                         strbuf_addf(&newname, "%s^", n->head_name);
 179                                         break;
 180                                 default:
 181                                         strbuf_addf(&newname, "%s~%d",
 182                                                     n->head_name, n->generation);
 183                                         break;
 184                                 }
 185                                 if (nth == 1)
 186                                         strbuf_addch(&newname, '^');
 187                                 else
 188                                         strbuf_addf(&newname, "^%d", nth);
 189                                 name_commit(p, strbuf_detach(&newname, NULL), 0);
 190                                 i++;
 191                                 name_first_parent_chain(p);
 192                         }
 193                 }
 194         } while (i);
 195 }
 196
 197 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 198 {
 199         if (!commit->object.flags) {
 200                 commit_list_insert(commit, seen_p);
 201                 return 1;
 202         }
 203         return 0;
 204 }
 205
 206 static void join_revs(struct commit_list **list_p,
 207                       struct commit_list **seen_p,
 208                       int num_rev, int extra)
 209 {
 210         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 211         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 212
 213         while (*list_p) {
 214                 struct commit_list *parents;
 215                 int still_interesting = !!interesting(*list_p);
 216                 struct commit *commit = pop_one_commit(list_p);
 217                 int flags = commit->object.flags & all_mask;
 218
 219                 if (!still_interesting && extra <= 0)
 220                         break;
 221
 222                 mark_seen(commit, seen_p);
 223                 if ((flags & all_revs) == all_revs)
 224                         flags |= UNINTERESTING;
 225                 parents = commit->parents;
 226
 227                 while (parents) {
 228                         struct commit *p = parents->item;
 229                         int this_flag = p->object.flags;
 230                         parents = parents->next;
 231                         if ((this_flag & flags) == flags)
 232                                 continue;
 233                         parse_commit(p);
 234                         if (mark_seen(p, seen_p) && !still_interesting)
 235                                 extra--;
 236                         p->object.flags |= flags;
 237                         commit_list_insert_by_date(p, list_p);
 238                 }
 239         }
 240
 241         /*
 242          * Postprocess to complete well-poisoning.
 243          *
 244          * At this point we have all the commits we have seen in
 245          * seen_p list.  Mark anything that can be reached from
 246          * uninteresting commits not interesting.
 247          */
 248         for (;;) {
 249                 int changed = 0;
 250                 struct commit_list *s;
 251                 for (s = *seen_p; s; s = s->next) {
 252                         struct commit *c = s->item;
 253                         struct commit_list *parents;
 254
 255                         if (((c->object.flags & all_revs) != all_revs) &&
 256                             !(c->object.flags & UNINTERESTING))
 257                                 continue;
 258
 259                         /* The current commit is either a merge base or
 260                          * already uninteresting one.  Mark its parents
 261                          * as uninteresting commits _only_ if they are
 262                          * already parsed.  No reason to find new ones
 263                          * here.
 264                          */
 265                         parents = c->parents;
 266                         while (parents) {
 267                                 struct commit *p = parents->item;
 268                                 parents = parents->next;
 269                                 if (!(p->object.flags & UNINTERESTING)) {
 270                                         p->object.flags |= UNINTERESTING;
 271                                         changed = 1;
 272                                 }
 273                         }
 274                 }
 275                 if (!changed)
 276                         break;
 277         }
 278 }
 279
 280 static void show_one_commit(struct commit *commit, int no_name)
 281 {
 282         struct strbuf pretty = STRBUF_INIT;
 283         const char *pretty_str = "(unavailable)";
 284         struct commit_name *name = commit->util;
 285
 286         if (commit->object.parsed) {
 287                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &pretty);
 288                 pretty_str = pretty.buf;
 289         }
 290         if (starts_with(pretty_str, "[PATCH] "))
 291                 pretty_str += 8;
 292
 293         if (!no_name) {
 294                 if (name && name->head_name) {
 295                         printf("[%s", name->head_name);
 296                         if (name->generation) {
 297                                 if (name->generation == 1)
 298                                         printf("^");
 299                                 else
 300                                         printf("~%d", name->generation);
 301                         }
 302                         printf("] ");
 303                 }
 304                 else
 305                         printf("[%s] ",
 306                                find_unique_abbrev(commit->object.sha1,
 307                                                   DEFAULT_ABBREV));
 308         }
 309         puts(pretty_str);
 310         strbuf_release(&pretty);
 311 }
 312
 313 static char *ref_name[MAX_REVS + 1];
 314 static int ref_name_cnt;
 315
 316 static const char *find_digit_prefix(const char *s, int *v)
 317 {
 318         const char *p;
 319         int ver;
 320         char ch;
 321
 322         for (p = s, ver = 0;
 323              '0' <= (ch = *p) && ch <= '9';
 324              p++)
 325                 ver = ver * 10 + ch - '0';
 326         *v = ver;
 327         return p;
 328 }
 329
 330
 331 static int version_cmp(const char *a, const char *b)
 332 {
 333         while (1) {
 334                 int va, vb;
 335
 336                 a = find_digit_prefix(a, &va);
 337                 b = find_digit_prefix(b, &vb);
 338                 if (va != vb)
 339                         return va - vb;
 340
 341                 while (1) {
 342                         int ca = *a;
 343                         int cb = *b;
 344                         if ('0' <= ca && ca <= '9')
 345                                 ca = 0;
 346                         if ('0' <= cb && cb <= '9')
 347                                 cb = 0;
 348                         if (ca != cb)
 349                                 return ca - cb;
 350                         if (!ca)
 351                                 break;
 352                         a++;
 353                         b++;
 354                 }
 355                 if (!*a && !*b)
 356                         return 0;
 357         }
 358 }
 359
 360 static int compare_ref_name(const void *a_, const void *b_)
 361 {
 362         const char * const*a = a_, * const*b = b_;
 363         return version_cmp(*a, *b);
 364 }
 365
 366 static void sort_ref_range(int bottom, int top)
 367 {
 368         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 369               compare_ref_name);
 370 }
 371
 372 static int append_ref(const char *refname, const struct object_id *oid,
 373                       int allow_dups)
 374 {
 375         struct commit *commit = lookup_commit_reference_gently(oid->hash, 1);
 376         int i;
 377
 378         if (!commit)
 379                 return 0;
 380
 381         if (!allow_dups) {
 382                 /* Avoid adding the same thing twice */
 383                 for (i = 0; i < ref_name_cnt; i++)
 384                         if (!strcmp(refname, ref_name[i]))
 385                                 return 0;
 386         }
 387         if (MAX_REVS <= ref_name_cnt) {
 388                 warning("ignoring %s; cannot handle more than %d refs",
 389                         refname, MAX_REVS);
 390                 return 0;
 391         }
 392         ref_name[ref_name_cnt++] = xstrdup(refname);
 393         ref_name[ref_name_cnt] = NULL;
 394         return 0;
 395 }
 396
 397 static int append_head_ref(const char *refname, const struct object_id *oid,
 398                            int flag, void *cb_data)
 399 {
 400         struct object_id tmp;
 401         int ofs = 11;
 402         if (!starts_with(refname, "refs/heads/"))
 403                 return 0;
 404         /* If both heads/foo and tags/foo exists, get_sha1 would
 405          * get confused.
 406          */
 407         if (get_sha1(refname + ofs, tmp.hash) || oidcmp(&tmp, oid))
 408                 ofs = 5;
 409         return append_ref(refname + ofs, oid, 0);
 410 }
 411
 412 static int append_remote_ref(const char *refname, const struct object_id *oid,
 413                              int flag, void *cb_data)
 414 {
 415         struct object_id tmp;
 416         int ofs = 13;
 417         if (!starts_with(refname, "refs/remotes/"))
 418                 return 0;
 419         /* If both heads/foo and tags/foo exists, get_sha1 would
 420          * get confused.
 421          */
 422         if (get_sha1(refname + ofs, tmp.hash) || oidcmp(&tmp, oid))
 423                 ofs = 5;
 424         return append_ref(refname + ofs, oid, 0);
 425 }
 426
 427 static int append_tag_ref(const char *refname, const struct object_id *oid,
 428                           int flag, void *cb_data)
 429 {
 430         if (!starts_with(refname, "refs/tags/"))
 431                 return 0;
 432         return append_ref(refname + 5, oid, 0);
 433 }
 434
 435 static const char *match_ref_pattern = NULL;
 436 static int match_ref_slash = 0;
 437 static int count_slash(const char *s)
 438 {
 439         int cnt = 0;
 440         while (*s)
 441                 if (*s++ == '/')
 442                         cnt++;
 443         return cnt;
 444 }
 445
 446 static int append_matching_ref(const char *refname, const struct object_id *oid,
 447                                int flag, void *cb_data)
 448 {
 449         /* we want to allow pattern hold/<asterisk> to show all
 450          * branches under refs/heads/hold/, and v0.99.9? to show
 451          * refs/tags/v0.99.9a and friends.
 452          */
 453         const char *tail;
 454         int slash = count_slash(refname);
 455         for (tail = refname; *tail && match_ref_slash < slash; )
 456                 if (*tail++ == '/')
 457                         slash--;
 458         if (!*tail)
 459                 return 0;
 460         if (wildmatch(match_ref_pattern, tail, 0, NULL))
 461                 return 0;
 462         if (starts_with(refname, "refs/heads/"))
 463                 return append_head_ref(refname, oid, flag, cb_data);
 464         if (starts_with(refname, "refs/tags/"))
 465                 return append_tag_ref(refname, oid, flag, cb_data);
 466         return append_ref(refname, oid, 0);
 467 }
 468
 469 static void snarf_refs(int head, int remotes)
 470 {
 471         if (head) {
 472                 int orig_cnt = ref_name_cnt;
 473
 474                 for_each_ref(append_head_ref, NULL);
 475                 sort_ref_range(orig_cnt, ref_name_cnt);
 476         }
 477         if (remotes) {
 478                 int orig_cnt = ref_name_cnt;
 479
 480                 for_each_ref(append_remote_ref, NULL);
 481                 sort_ref_range(orig_cnt, ref_name_cnt);
 482         }
 483 }
 484
 485 static int rev_is_head(char *head, int headlen, char *name,
 486                        unsigned char *head_sha1, unsigned char *sha1)
 487 {
 488         if ((!head[0]) ||
 489             (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
 490                 return 0;
 491         if (starts_with(head, "refs/heads/"))
 492                 head += 11;
 493         if (starts_with(name, "refs/heads/"))
 494                 name += 11;
 495         else if (starts_with(name, "heads/"))
 496                 name += 6;
 497         return !strcmp(head, name);
 498 }
 499
 500 static int show_merge_base(struct commit_list *seen, int num_rev)
 501 {
 502         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 503         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 504         int exit_status = 1;
 505
 506         while (seen) {
 507                 struct commit *commit = pop_one_commit(&seen);
 508                 int flags = commit->object.flags & all_mask;
 509                 if (!(flags & UNINTERESTING) &&
 510                     ((flags & all_revs) == all_revs)) {
 511                         puts(sha1_to_hex(commit->object.sha1));
 512                         exit_status = 0;
 513                         commit->object.flags |= UNINTERESTING;
 514                 }
 515         }
 516         return exit_status;
 517 }
 518
 519 static int show_independent(struct commit **rev,
 520                             int num_rev,
 521                             char **ref_name,
 522                             unsigned int *rev_mask)
 523 {
 524         int i;
 525
 526         for (i = 0; i < num_rev; i++) {
 527                 struct commit *commit = rev[i];
 528                 unsigned int flag = rev_mask[i];
 529
 530                 if (commit->object.flags == flag)
 531                         puts(sha1_to_hex(commit->object.sha1));
 532                 commit->object.flags |= UNINTERESTING;
 533         }
 534         return 0;
 535 }
 536
 537 static void append_one_rev(const char *av)
 538 {
 539         struct object_id revkey;
 540         if (!get_sha1(av, revkey.hash)) {
 541                 append_ref(av, &revkey, 0);
 542                 return;
 543         }
 544         if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
 545                 /* glob style match */
 546                 int saved_matches = ref_name_cnt;
 547
 548                 match_ref_pattern = av;
 549                 match_ref_slash = count_slash(av);
 550                 for_each_ref(append_matching_ref, NULL);
 551                 if (saved_matches == ref_name_cnt &&
 552                     ref_name_cnt < MAX_REVS)
 553                         error("no matching refs with %s", av);
 554                 if (saved_matches + 1 < ref_name_cnt)
 555                         sort_ref_range(saved_matches, ref_name_cnt);
 556                 return;
 557         }
 558         die("bad sha1 reference %s", av);
 559 }
 560
 561 static int git_show_branch_config(const char *var, const char *value, void *cb)
 562 {
 563         if (!strcmp(var, "showbranch.default")) {
 564                 if (!value)
 565                         return config_error_nonbool(var);
 566                 /*
 567                  * default_arg is now passed to parse_options(), so we need to
 568                  * mimic the real argv a bit better.
 569                  */
 570                 if (!default_num) {
 571                         default_alloc = 20;
 572                         default_arg = xcalloc(default_alloc, sizeof(*default_arg));
 573                         default_arg[default_num++] = "show-branch";
 574                 } else if (default_alloc <= default_num + 1) {
 575                         default_alloc = default_alloc * 3 / 2 + 20;
 576                         REALLOC_ARRAY(default_arg, default_alloc);
 577                 }
 578                 default_arg[default_num++] = xstrdup(value);
 579                 default_arg[default_num] = NULL;
 580                 return 0;
 581         }
 582
 583         if (!strcmp(var, "color.showbranch")) {
 584                 showbranch_use_color = git_config_colorbool(var, value);
 585                 return 0;
 586         }
 587
 588         return git_color_default_config(var, value, cb);
 589 }
 590
 591 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
 592 {
 593         /* If the commit is tip of the named branches, do not
 594          * omit it.
 595          * Otherwise, if it is a merge that is reachable from only one
 596          * tip, it is not that interesting.
 597          */
 598         int i, flag, count;
 599         for (i = 0; i < n; i++)
 600                 if (rev[i] == commit)
 601                         return 0;
 602         flag = commit->object.flags;
 603         for (i = count = 0; i < n; i++) {
 604                 if (flag & (1u << (i + REV_SHIFT)))
 605                         count++;
 606         }
 607         if (count == 1)
 608                 return 1;
 609         return 0;
 610 }
 611
 612 static int reflog = 0;
 613
 614 static int parse_reflog_param(const struct option *opt, const char *arg,
 615                               int unset)
 616 {
 617         char *ep;
 618         const char **base = (const char **)opt->value;
 619         if (!arg)
 620                 arg = "";
 621         reflog = strtoul(arg, &ep, 10);
 622         if (*ep == ',')
 623                 *base = ep + 1;
 624         else if (*ep)
 625                 return error("unrecognized reflog param '%s'", arg);
 626         else
 627                 *base = NULL;
 628         if (reflog <= 0)
 629                 reflog = DEFAULT_REFLOG;
 630         return 0;
 631 }
 632
 633 int cmd_show_branch(int ac, const char **av, const char *prefix)
 634 {
 635         struct commit *rev[MAX_REVS], *commit;
 636         char *reflog_msg[MAX_REVS];
 637         struct commit_list *list = NULL, *seen = NULL;
 638         unsigned int rev_mask[MAX_REVS];
 639         int num_rev, i, extra = 0;
 640         int all_heads = 0, all_remotes = 0;
 641         int all_mask, all_revs;
 642         enum rev_sort_order sort_order = REV_SORT_IN_GRAPH_ORDER;
 643         char head[128];
 644         const char *head_p;
 645         int head_len;
 646         struct object_id head_oid;
 647         int merge_base = 0;
 648         int independent = 0;
 649         int no_name = 0;
 650         int sha1_name = 0;
 651         int shown_merge_point = 0;
 652         int with_current_branch = 0;
 653         int head_at = -1;
 654         int topics = 0;
 655         int dense = 1;
 656         const char *reflog_base = NULL;
 657         struct option builtin_show_branch_options[] = {
 658                 OPT_BOOL('a', "all", &all_heads,
 659                          N_("show remote-tracking and local branches")),
 660                 OPT_BOOL('r', "remotes", &all_remotes,
 661                          N_("show remote-tracking branches")),
 662                 OPT__COLOR(&showbranch_use_color,
 663                             N_("color '*!+-' corresponding to the branch")),
 664                 { OPTION_INTEGER, 0, "more", &extra, N_("n"),
 665                             N_("show <n> more commits after the common ancestor"),
 666                             PARSE_OPT_OPTARG, NULL, (intptr_t)1 },
 667                 OPT_SET_INT(0, "list", &extra, N_("synonym to more=-1"), -1),
 668                 OPT_BOOL(0, "no-name", &no_name, N_("suppress naming strings")),
 669                 OPT_BOOL(0, "current", &with_current_branch,
 670                          N_("include the current branch")),
 671                 OPT_BOOL(0, "sha1-name", &sha1_name,
 672                          N_("name commits with their object names")),
 673                 OPT_BOOL(0, "merge-base", &merge_base,
 674                          N_("show possible merge bases")),
 675                 OPT_BOOL(0, "independent", &independent,
 676                             N_("show refs unreachable from any other ref")),
 677                 OPT_SET_INT(0, "topo-order", &sort_order,
 678                             N_("show commits in topological order"),
 679                             REV_SORT_IN_GRAPH_ORDER),
 680                 OPT_BOOL(0, "topics", &topics,
 681                          N_("show only commits not on the first branch")),
 682                 OPT_SET_INT(0, "sparse", &dense,
 683                             N_("show merges reachable from only one tip"), 0),
 684                 OPT_SET_INT(0, "date-order", &sort_order,
 685                             N_("topologically sort, maintaining date order "
 686                                "where possible"),
 687                             REV_SORT_BY_COMMIT_DATE),
 688                 { OPTION_CALLBACK, 'g', "reflog", &reflog_base, N_("<n>[,<base>]"),
 689                             N_("show <n> most recent ref-log entries starting at "
 690                                "base"),
 691                             PARSE_OPT_OPTARG | PARSE_OPT_LITERAL_ARGHELP,
 692                             parse_reflog_param },
 693                 OPT_END()
 694         };
 695
 696         git_config(git_show_branch_config, NULL);
 697
 698         /* If nothing is specified, try the default first */
 699         if (ac == 1 && default_num) {
 700                 ac = default_num;
 701                 av = default_arg;
 702         }
 703
 704         ac = parse_options(ac, av, prefix, builtin_show_branch_options,
 705                            show_branch_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 706         if (all_heads)
 707                 all_remotes = 1;
 708
 709         if (extra || reflog) {
 710                 /* "listing" mode is incompatible with
 711                  * independent nor merge-base modes.
 712                  */
 713                 if (independent || merge_base)
 714                         usage_with_options(show_branch_usage,
 715                                            builtin_show_branch_options);
 716                 if (reflog && ((0 < extra) || all_heads || all_remotes))
 717                         /*
 718                          * Asking for --more in reflog mode does not
 719                          * make sense.  --list is Ok.
 720                          *
 721                          * Also --all and --remotes do not make sense either.
 722                          */
 723                         die("--reflog is incompatible with --all, --remotes, "
 724                             "--independent or --merge-base");
 725         }
 726
 727         /* If nothing is specified, show all branches by default */
 728         if (ac <= topics && all_heads + all_remotes == 0)
 729                 all_heads = 1;
 730
 731         if (reflog) {
 732                 struct object_id oid;
 733                 char nth_desc[256];
 734                 char *ref;
 735                 int base = 0;
 736                 unsigned int flags = 0;
 737
 738                 if (ac == 0) {
 739                         static const char *fake_av[2];
 740
 741                         fake_av[0] = resolve_refdup("HEAD",
 742                                                     RESOLVE_REF_READING,
 743                                                     oid.hash, NULL);
 744                         fake_av[1] = NULL;
 745                         av = fake_av;
 746                         ac = 1;
 747                 }
 748                 if (ac != 1)
 749                         die("--reflog option needs one branch name");
 750
 751                 if (MAX_REVS < reflog)
 752                         die("Only %d entries can be shown at one time.",
 753                             MAX_REVS);
 754                 if (!dwim_ref(*av, strlen(*av), oid.hash, &ref))
 755                         die("No such ref %s", *av);
 756
 757                 /* Has the base been specified? */
 758                 if (reflog_base) {
 759                         char *ep;
 760                         base = strtoul(reflog_base, &ep, 10);
 761                         if (*ep) {
 762                                 /* Ah, that is a date spec... */
 763                                 unsigned long at;
 764                                 at = approxidate(reflog_base);
 765                                 read_ref_at(ref, flags, at, -1, oid.hash, NULL,
 766                                             NULL, NULL, &base);
 767                         }
 768                 }
 769
 770                 for (i = 0; i < reflog; i++) {
 771                         char *logmsg;
 772                         const char *msg;
 773                         unsigned long timestamp;
 774                         int tz;
 775
 776                         if (read_ref_at(ref, flags, 0, base+i, oid.hash, &logmsg,
 777                                         &timestamp, &tz, NULL)) {
 778                                 reflog = i;
 779                                 break;
 780                         }
 781                         msg = strchr(logmsg, '\t');
 782                         if (!msg)
 783                                 msg = "(none)";
 784                         else
 785                                 msg++;
 786                         reflog_msg[i] = xstrfmt("(%s) %s",
 787                                                 show_date(timestamp, tz,
 788                                                           DATE_MODE(RELATIVE)),
 789                                                 msg);
 790                         free(logmsg);
 791                         sprintf(nth_desc, "%s@{%d}", *av, base+i);
 792                         append_ref(nth_desc, &oid, 1);
 793                 }
 794                 free(ref);
 795         }
 796         else {
 797                 while (0 < ac) {
 798                         append_one_rev(*av);
 799                         ac--; av++;
 800                 }
 801                 if (all_heads + all_remotes)
 802                         snarf_refs(all_heads, all_remotes);
 803         }
 804
 805         head_p = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
 806                                     head_oid.hash, NULL);
 807         if (head_p) {
 808                 head_len = strlen(head_p);
 809                 memcpy(head, head_p, head_len + 1);
 810         }
 811         else {
 812                 head_len = 0;
 813                 head[0] = 0;
 814         }
 815
 816         if (with_current_branch && head_p) {
 817                 int has_head = 0;
 818                 for (i = 0; !has_head && i < ref_name_cnt; i++) {
 819                         /* We are only interested in adding the branch
 820                          * HEAD points at.
 821                          */
 822                         if (rev_is_head(head,
 823                                         head_len,
 824                                         ref_name[i],
 825                                         head_oid.hash, NULL))
 826                                 has_head++;
 827                 }
 828                 if (!has_head) {
 829                         int offset = starts_with(head, "refs/heads/") ? 11 : 0;
 830                         append_one_rev(head + offset);
 831                 }
 832         }
 833
 834         if (!ref_name_cnt) {
 835                 fprintf(stderr, "No revs to be shown.\n");
 836                 exit(0);
 837         }
 838
 839         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 840                 struct object_id revkey;
 841                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 842
 843                 if (MAX_REVS <= num_rev)
 844                         die("cannot handle more than %d revs.", MAX_REVS);
 845                 if (get_sha1(ref_name[num_rev], revkey.hash))
 846                         die("'%s' is not a valid ref.", ref_name[num_rev]);
 847                 commit = lookup_commit_reference(revkey.hash);
 848                 if (!commit)
 849                         die("cannot find commit %s (%s)",
 850                             ref_name[num_rev], oid_to_hex(&revkey));
 851                 parse_commit(commit);
 852                 mark_seen(commit, &seen);
 853
 854                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 855                  * and so on.  REV_SHIFT bits from bit 0 are used for
 856                  * internal bookkeeping.
 857                  */
 858                 commit->object.flags |= flag;
 859                 if (commit->object.flags == flag)
 860                         commit_list_insert_by_date(commit, &list);
 861                 rev[num_rev] = commit;
 862         }
 863         for (i = 0; i < num_rev; i++)
 864                 rev_mask[i] = rev[i]->object.flags;
 865
 866         if (0 <= extra)
 867                 join_revs(&list, &seen, num_rev, extra);
 868
 869         commit_list_sort_by_date(&seen);
 870
 871         if (merge_base)
 872                 return show_merge_base(seen, num_rev);
 873
 874         if (independent)
 875                 return show_independent(rev, num_rev, ref_name, rev_mask);
 876
 877         /* Show list; --more=-1 means list-only */
 878         if (1 < num_rev || extra < 0) {
 879                 for (i = 0; i < num_rev; i++) {
 880                         int j;
 881                         int is_head = rev_is_head(head,
 882                                                   head_len,
 883                                                   ref_name[i],
 884                                                   head_oid.hash,
 885                                                   rev[i]->object.sha1);
 886                         if (extra < 0)
 887                                 printf("%c [%s] ",
 888                                        is_head ? '*' : ' ', ref_name[i]);
 889                         else {
 890                                 for (j = 0; j < i; j++)
 891                                         putchar(' ');
 892                                 printf("%s%c%s [%s] ",
 893                                        get_color_code(i),
 894                                        is_head ? '*' : '!',
 895                                        get_color_reset_code(), ref_name[i]);
 896                         }
 897
 898                         if (!reflog) {
 899                                 /* header lines never need name */
 900                                 show_one_commit(rev[i], 1);
 901                         }
 902                         else
 903                                 puts(reflog_msg[i]);
 904
 905                         if (is_head)
 906                                 head_at = i;
 907                 }
 908                 if (0 <= extra) {
 909                         for (i = 0; i < num_rev; i++)
 910                                 putchar('-');
 911                         putchar('\n');
 912                 }
 913         }
 914         if (extra < 0)
 915                 exit(0);
 916
 917         /* Sort topologically */
 918         sort_in_topological_order(&seen, sort_order);
 919
 920         /* Give names to commits */
 921         if (!sha1_name && !no_name)
 922                 name_commits(seen, rev, ref_name, num_rev);
 923
 924         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 925         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 926
 927         while (seen) {
 928                 struct commit *commit = pop_one_commit(&seen);
 929                 int this_flag = commit->object.flags;
 930                 int is_merge_point = ((this_flag & all_revs) == all_revs);
 931
 932                 shown_merge_point |= is_merge_point;
 933
 934                 if (1 < num_rev) {
 935                         int is_merge = !!(commit->parents &&
 936                                           commit->parents->next);
 937                         if (topics &&
 938                             !is_merge_point &&
 939                             (this_flag & (1u << REV_SHIFT)))
 940                                 continue;
 941                         if (dense && is_merge &&
 942                             omit_in_dense(commit, rev, num_rev))
 943                                 continue;
 944                         for (i = 0; i < num_rev; i++) {
 945                                 int mark;
 946                                 if (!(this_flag & (1u << (i + REV_SHIFT))))
 947                                         mark = ' ';
 948                                 else if (is_merge)
 949                                         mark = '-';
 950                                 else if (i == head_at)
 951                                         mark = '*';
 952                                 else
 953                                         mark = '+';
 954                                 printf("%s%c%s",
 955                                        get_color_code(i),
 956                                        mark, get_color_reset_code());
 957                         }
 958                         putchar(' ');
 959                 }
 960                 show_one_commit(commit, no_name);
 961
 962                 if (shown_merge_point && --extra < 0)
 963                         break;
 964         }
 965         return 0;
 966 }