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 unsigned char *sha1,
 373                       int allow_dups)
 374 {
 375         struct commit *commit = lookup_commit_reference_gently(sha1, 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 unsigned char *sha1, int flag, void *cb_data)
 398 {
 399         unsigned char tmp[20];
 400         int ofs = 11;
 401         if (!starts_with(refname, "refs/heads/"))
 402                 return 0;
 403         /* If both heads/foo and tags/foo exists, get_sha1 would
 404          * get confused.
 405          */
 406         if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
 407                 ofs = 5;
 408         return append_ref(refname + ofs, sha1, 0);
 409 }
 410
 411 static int append_remote_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 412 {
 413         unsigned char tmp[20];
 414         int ofs = 13;
 415         if (!starts_with(refname, "refs/remotes/"))
 416                 return 0;
 417         /* If both heads/foo and tags/foo exists, get_sha1 would
 418          * get confused.
 419          */
 420         if (get_sha1(refname + ofs, tmp) || hashcmp(tmp, sha1))
 421                 ofs = 5;
 422         return append_ref(refname + ofs, sha1, 0);
 423 }
 424
 425 static int append_tag_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 426 {
 427         if (!starts_with(refname, "refs/tags/"))
 428                 return 0;
 429         return append_ref(refname + 5, sha1, 0);
 430 }
 431
 432 static const char *match_ref_pattern = NULL;
 433 static int match_ref_slash = 0;
 434 static int count_slash(const char *s)
 435 {
 436         int cnt = 0;
 437         while (*s)
 438                 if (*s++ == '/')
 439                         cnt++;
 440         return cnt;
 441 }
 442
 443 static int append_matching_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 444 {
 445         /* we want to allow pattern hold/<asterisk> to show all
 446          * branches under refs/heads/hold/, and v0.99.9? to show
 447          * refs/tags/v0.99.9a and friends.
 448          */
 449         const char *tail;
 450         int slash = count_slash(refname);
 451         for (tail = refname; *tail && match_ref_slash < slash; )
 452                 if (*tail++ == '/')
 453                         slash--;
 454         if (!*tail)
 455                 return 0;
 456         if (wildmatch(match_ref_pattern, tail, 0, NULL))
 457                 return 0;
 458         if (starts_with(refname, "refs/heads/"))
 459                 return append_head_ref(refname, sha1, flag, cb_data);
 460         if (starts_with(refname, "refs/tags/"))
 461                 return append_tag_ref(refname, sha1, flag, cb_data);
 462         return append_ref(refname, sha1, 0);
 463 }
 464
 465 static void snarf_refs(int head, int remotes)
 466 {
 467         if (head) {
 468                 int orig_cnt = ref_name_cnt;
 469                 for_each_ref(append_head_ref, NULL);
 470                 sort_ref_range(orig_cnt, ref_name_cnt);
 471         }
 472         if (remotes) {
 473                 int orig_cnt = ref_name_cnt;
 474                 for_each_ref(append_remote_ref, NULL);
 475                 sort_ref_range(orig_cnt, ref_name_cnt);
 476         }
 477 }
 478
 479 static int rev_is_head(char *head, int headlen, char *name,
 480                        unsigned char *head_sha1, unsigned char *sha1)
 481 {
 482         if ((!head[0]) ||
 483             (head_sha1 && sha1 && hashcmp(head_sha1, sha1)))
 484                 return 0;
 485         if (starts_with(head, "refs/heads/"))
 486                 head += 11;
 487         if (starts_with(name, "refs/heads/"))
 488                 name += 11;
 489         else if (starts_with(name, "heads/"))
 490                 name += 6;
 491         return !strcmp(head, name);
 492 }
 493
 494 static int show_merge_base(struct commit_list *seen, int num_rev)
 495 {
 496         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 497         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 498         int exit_status = 1;
 499
 500         while (seen) {
 501                 struct commit *commit = pop_one_commit(&seen);
 502                 int flags = commit->object.flags & all_mask;
 503                 if (!(flags & UNINTERESTING) &&
 504                     ((flags & all_revs) == all_revs)) {
 505                         puts(sha1_to_hex(commit->object.sha1));
 506                         exit_status = 0;
 507                         commit->object.flags |= UNINTERESTING;
 508                 }
 509         }
 510         return exit_status;
 511 }
 512
 513 static int show_independent(struct commit **rev,
 514                             int num_rev,
 515                             char **ref_name,
 516                             unsigned int *rev_mask)
 517 {
 518         int i;
 519
 520         for (i = 0; i < num_rev; i++) {
 521                 struct commit *commit = rev[i];
 522                 unsigned int flag = rev_mask[i];
 523
 524                 if (commit->object.flags == flag)
 525                         puts(sha1_to_hex(commit->object.sha1));
 526                 commit->object.flags |= UNINTERESTING;
 527         }
 528         return 0;
 529 }
 530
 531 static void append_one_rev(const char *av)
 532 {
 533         unsigned char revkey[20];
 534         if (!get_sha1(av, revkey)) {
 535                 append_ref(av, revkey, 0);
 536                 return;
 537         }
 538         if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
 539                 /* glob style match */
 540                 int saved_matches = ref_name_cnt;
 541                 match_ref_pattern = av;
 542                 match_ref_slash = count_slash(av);
 543                 for_each_ref(append_matching_ref, NULL);
 544                 if (saved_matches == ref_name_cnt &&
 545                     ref_name_cnt < MAX_REVS)
 546                         error("no matching refs with %s", av);
 547                 if (saved_matches + 1 < ref_name_cnt)
 548                         sort_ref_range(saved_matches, ref_name_cnt);
 549                 return;
 550         }
 551         die("bad sha1 reference %s", av);
 552 }
 553
 554 static int git_show_branch_config(const char *var, const char *value, void *cb)
 555 {
 556         if (!strcmp(var, "showbranch.default")) {
 557                 if (!value)
 558                         return config_error_nonbool(var);
 559                 /*
 560                  * default_arg is now passed to parse_options(), so we need to
 561                  * mimic the real argv a bit better.
 562                  */
 563                 if (!default_num) {
 564                         default_alloc = 20;
 565                         default_arg = xcalloc(default_alloc, sizeof(*default_arg));
 566                         default_arg[default_num++] = "show-branch";
 567                 } else if (default_alloc <= default_num + 1) {
 568                         default_alloc = default_alloc * 3 / 2 + 20;
 569                         REALLOC_ARRAY(default_arg, default_alloc);
 570                 }
 571                 default_arg[default_num++] = xstrdup(value);
 572                 default_arg[default_num] = NULL;
 573                 return 0;
 574         }
 575
 576         if (!strcmp(var, "color.showbranch")) {
 577                 showbranch_use_color = git_config_colorbool(var, value);
 578                 return 0;
 579         }
 580
 581         return git_color_default_config(var, value, cb);
 582 }
 583
 584 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
 585 {
 586         /* If the commit is tip of the named branches, do not
 587          * omit it.
 588          * Otherwise, if it is a merge that is reachable from only one
 589          * tip, it is not that interesting.
 590          */
 591         int i, flag, count;
 592         for (i = 0; i < n; i++)
 593                 if (rev[i] == commit)
 594                         return 0;
 595         flag = commit->object.flags;
 596         for (i = count = 0; i < n; i++) {
 597                 if (flag & (1u << (i + REV_SHIFT)))
 598                         count++;
 599         }
 600         if (count == 1)
 601                 return 1;
 602         return 0;
 603 }
 604
 605 static int reflog = 0;
 606
 607 static int parse_reflog_param(const struct option *opt, const char *arg,
 608                               int unset)
 609 {
 610         char *ep;
 611         const char **base = (const char **)opt->value;
 612         if (!arg)
 613                 arg = "";
 614         reflog = strtoul(arg, &ep, 10);
 615         if (*ep == ',')
 616                 *base = ep + 1;
 617         else if (*ep)
 618                 return error("unrecognized reflog param '%s'", arg);
 619         else
 620                 *base = NULL;
 621         if (reflog <= 0)
 622                 reflog = DEFAULT_REFLOG;
 623         return 0;
 624 }
 625
 626 int cmd_show_branch(int ac, const char **av, const char *prefix)
 627 {
 628         struct commit *rev[MAX_REVS], *commit;
 629         char *reflog_msg[MAX_REVS];
 630         struct commit_list *list = NULL, *seen = NULL;
 631         unsigned int rev_mask[MAX_REVS];
 632         int num_rev, i, extra = 0;
 633         int all_heads = 0, all_remotes = 0;
 634         int all_mask, all_revs;
 635         enum rev_sort_order sort_order = REV_SORT_IN_GRAPH_ORDER;
 636         char head[128];
 637         const char *head_p;
 638         int head_len;
 639         unsigned char head_sha1[20];
 640         int merge_base = 0;
 641         int independent = 0;
 642         int no_name = 0;
 643         int sha1_name = 0;
 644         int shown_merge_point = 0;
 645         int with_current_branch = 0;
 646         int head_at = -1;
 647         int topics = 0;
 648         int dense = 1;
 649         const char *reflog_base = NULL;
 650         struct option builtin_show_branch_options[] = {
 651                 OPT_BOOL('a', "all", &all_heads,
 652                          N_("show remote-tracking and local branches")),
 653                 OPT_BOOL('r', "remotes", &all_remotes,
 654                          N_("show remote-tracking branches")),
 655                 OPT__COLOR(&showbranch_use_color,
 656                             N_("color '*!+-' corresponding to the branch")),
 657                 { OPTION_INTEGER, 0, "more", &extra, N_("n"),
 658                             N_("show <n> more commits after the common ancestor"),
 659                             PARSE_OPT_OPTARG, NULL, (intptr_t)1 },
 660                 OPT_SET_INT(0, "list", &extra, N_("synonym to more=-1"), -1),
 661                 OPT_BOOL(0, "no-name", &no_name, N_("suppress naming strings")),
 662                 OPT_BOOL(0, "current", &with_current_branch,
 663                          N_("include the current branch")),
 664                 OPT_BOOL(0, "sha1-name", &sha1_name,
 665                          N_("name commits with their object names")),
 666                 OPT_BOOL(0, "merge-base", &merge_base,
 667                          N_("show possible merge bases")),
 668                 OPT_BOOL(0, "independent", &independent,
 669                             N_("show refs unreachable from any other ref")),
 670                 OPT_SET_INT(0, "topo-order", &sort_order,
 671                             N_("show commits in topological order"),
 672                             REV_SORT_IN_GRAPH_ORDER),
 673                 OPT_BOOL(0, "topics", &topics,
 674                          N_("show only commits not on the first branch")),
 675                 OPT_SET_INT(0, "sparse", &dense,
 676                             N_("show merges reachable from only one tip"), 0),
 677                 OPT_SET_INT(0, "date-order", &sort_order,
 678                             N_("topologically sort, maintaining date order "
 679                                "where possible"),
 680                             REV_SORT_BY_COMMIT_DATE),
 681                 { OPTION_CALLBACK, 'g', "reflog", &reflog_base, N_("<n>[,<base>]"),
 682                             N_("show <n> most recent ref-log entries starting at "
 683                                "base"),
 684                             PARSE_OPT_OPTARG | PARSE_OPT_LITERAL_ARGHELP,
 685                             parse_reflog_param },
 686                 OPT_END()
 687         };
 688
 689         git_config(git_show_branch_config, NULL);
 690
 691         /* If nothing is specified, try the default first */
 692         if (ac == 1 && default_num) {
 693                 ac = default_num;
 694                 av = default_arg;
 695         }
 696
 697         ac = parse_options(ac, av, prefix, builtin_show_branch_options,
 698                            show_branch_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 699         if (all_heads)
 700                 all_remotes = 1;
 701
 702         if (extra || reflog) {
 703                 /* "listing" mode is incompatible with
 704                  * independent nor merge-base modes.
 705                  */
 706                 if (independent || merge_base)
 707                         usage_with_options(show_branch_usage,
 708                                            builtin_show_branch_options);
 709                 if (reflog && ((0 < extra) || all_heads || all_remotes))
 710                         /*
 711                          * Asking for --more in reflog mode does not
 712                          * make sense.  --list is Ok.
 713                          *
 714                          * Also --all and --remotes do not make sense either.
 715                          */
 716                         die("--reflog is incompatible with --all, --remotes, "
 717                             "--independent or --merge-base");
 718         }
 719
 720         /* If nothing is specified, show all branches by default */
 721         if (ac + all_heads + all_remotes == 0)
 722                 all_heads = 1;
 723
 724         if (reflog) {
 725                 unsigned char sha1[20];
 726                 char nth_desc[256];
 727                 char *ref;
 728                 int base = 0;
 729                 unsigned int flags = 0;
 730
 731                 if (ac == 0) {
 732                         static const char *fake_av[2];
 733
 734                         fake_av[0] = resolve_refdup("HEAD",
 735                                                     RESOLVE_REF_READING,
 736                                                     sha1, NULL);
 737                         fake_av[1] = NULL;
 738                         av = fake_av;
 739                         ac = 1;
 740                 }
 741                 if (ac != 1)
 742                         die("--reflog option needs one branch name");
 743
 744                 if (MAX_REVS < reflog)
 745                         die("Only %d entries can be shown at one time.",
 746                             MAX_REVS);
 747                 if (!dwim_ref(*av, strlen(*av), sha1, &ref))
 748                         die("No such ref %s", *av);
 749
 750                 /* Has the base been specified? */
 751                 if (reflog_base) {
 752                         char *ep;
 753                         base = strtoul(reflog_base, &ep, 10);
 754                         if (*ep) {
 755                                 /* Ah, that is a date spec... */
 756                                 unsigned long at;
 757                                 at = approxidate(reflog_base);
 758                                 read_ref_at(ref, flags, at, -1, sha1, NULL,
 759                                             NULL, NULL, &base);
 760                         }
 761                 }
 762
 763                 for (i = 0; i < reflog; i++) {
 764                         char *logmsg;
 765                         const char *msg;
 766                         unsigned long timestamp;
 767                         int tz;
 768
 769                         if (read_ref_at(ref, flags, 0, base+i, sha1, &logmsg,
 770                                         &timestamp, &tz, NULL)) {
 771                                 reflog = i;
 772                                 break;
 773                         }
 774                         msg = strchr(logmsg, '\t');
 775                         if (!msg)
 776                                 msg = "(none)";
 777                         else
 778                                 msg++;
 779                         reflog_msg[i] = xstrfmt("(%s) %s",
 780                                                 show_date(timestamp, tz, 1),
 781                                                 msg);
 782                         free(logmsg);
 783                         sprintf(nth_desc, "%s@{%d}", *av, base+i);
 784                         append_ref(nth_desc, sha1, 1);
 785                 }
 786                 free(ref);
 787         }
 788         else if (all_heads + all_remotes)
 789                 snarf_refs(all_heads, all_remotes);
 790         else {
 791                 while (0 < ac) {
 792                         append_one_rev(*av);
 793                         ac--; av++;
 794                 }
 795         }
 796
 797         head_p = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
 798                                     head_sha1, NULL);
 799         if (head_p) {
 800                 head_len = strlen(head_p);
 801                 memcpy(head, head_p, head_len + 1);
 802         }
 803         else {
 804                 head_len = 0;
 805                 head[0] = 0;
 806         }
 807
 808         if (with_current_branch && head_p) {
 809                 int has_head = 0;
 810                 for (i = 0; !has_head && i < ref_name_cnt; i++) {
 811                         /* We are only interested in adding the branch
 812                          * HEAD points at.
 813                          */
 814                         if (rev_is_head(head,
 815                                         head_len,
 816                                         ref_name[i],
 817                                         head_sha1, NULL))
 818                                 has_head++;
 819                 }
 820                 if (!has_head) {
 821                         int offset = starts_with(head, "refs/heads/") ? 11 : 0;
 822                         append_one_rev(head + offset);
 823                 }
 824         }
 825
 826         if (!ref_name_cnt) {
 827                 fprintf(stderr, "No revs to be shown.\n");
 828                 exit(0);
 829         }
 830
 831         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 832                 unsigned char revkey[20];
 833                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 834
 835                 if (MAX_REVS <= num_rev)
 836                         die("cannot handle more than %d revs.", MAX_REVS);
 837                 if (get_sha1(ref_name[num_rev], revkey))
 838                         die("'%s' is not a valid ref.", ref_name[num_rev]);
 839                 commit = lookup_commit_reference(revkey);
 840                 if (!commit)
 841                         die("cannot find commit %s (%s)",
 842                             ref_name[num_rev], revkey);
 843                 parse_commit(commit);
 844                 mark_seen(commit, &seen);
 845
 846                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 847                  * and so on.  REV_SHIFT bits from bit 0 are used for
 848                  * internal bookkeeping.
 849                  */
 850                 commit->object.flags |= flag;
 851                 if (commit->object.flags == flag)
 852                         commit_list_insert_by_date(commit, &list);
 853                 rev[num_rev] = commit;
 854         }
 855         for (i = 0; i < num_rev; i++)
 856                 rev_mask[i] = rev[i]->object.flags;
 857
 858         if (0 <= extra)
 859                 join_revs(&list, &seen, num_rev, extra);
 860
 861         commit_list_sort_by_date(&seen);
 862
 863         if (merge_base)
 864                 return show_merge_base(seen, num_rev);
 865
 866         if (independent)
 867                 return show_independent(rev, num_rev, ref_name, rev_mask);
 868
 869         /* Show list; --more=-1 means list-only */
 870         if (1 < num_rev || extra < 0) {
 871                 for (i = 0; i < num_rev; i++) {
 872                         int j;
 873                         int is_head = rev_is_head(head,
 874                                                   head_len,
 875                                                   ref_name[i],
 876                                                   head_sha1,
 877                                                   rev[i]->object.sha1);
 878                         if (extra < 0)
 879                                 printf("%c [%s] ",
 880                                        is_head ? '*' : ' ', ref_name[i]);
 881                         else {
 882                                 for (j = 0; j < i; j++)
 883                                         putchar(' ');
 884                                 printf("%s%c%s [%s] ",
 885                                        get_color_code(i),
 886                                        is_head ? '*' : '!',
 887                                        get_color_reset_code(), ref_name[i]);
 888                         }
 889
 890                         if (!reflog) {
 891                                 /* header lines never need name */
 892                                 show_one_commit(rev[i], 1);
 893                         }
 894                         else
 895                                 puts(reflog_msg[i]);
 896
 897                         if (is_head)
 898                                 head_at = i;
 899                 }
 900                 if (0 <= extra) {
 901                         for (i = 0; i < num_rev; i++)
 902                                 putchar('-');
 903                         putchar('\n');
 904                 }
 905         }
 906         if (extra < 0)
 907                 exit(0);
 908
 909         /* Sort topologically */
 910         sort_in_topological_order(&seen, sort_order);
 911
 912         /* Give names to commits */
 913         if (!sha1_name && !no_name)
 914                 name_commits(seen, rev, ref_name, num_rev);
 915
 916         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 917         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 918
 919         while (seen) {
 920                 struct commit *commit = pop_one_commit(&seen);
 921                 int this_flag = commit->object.flags;
 922                 int is_merge_point = ((this_flag & all_revs) == all_revs);
 923
 924                 shown_merge_point |= is_merge_point;
 925
 926                 if (1 < num_rev) {
 927                         int is_merge = !!(commit->parents &&
 928                                           commit->parents->next);
 929                         if (topics &&
 930                             !is_merge_point &&
 931                             (this_flag & (1u << REV_SHIFT)))
 932                                 continue;
 933                         if (dense && is_merge &&
 934                             omit_in_dense(commit, rev, num_rev))
 935                                 continue;
 936                         for (i = 0; i < num_rev; i++) {
 937                                 int mark;
 938                                 if (!(this_flag & (1u << (i + REV_SHIFT))))
 939                                         mark = ' ';
 940                                 else if (is_merge)
 941                                         mark = '-';
 942                                 else if (i == head_at)
 943                                         mark = '*';
 944                                 else
 945                                         mark = '+';
 946                                 printf("%s%c%s",
 947                                        get_color_code(i),
 948                                        mark, get_color_reset_code());
 949                         }
 950                         putchar(' ');
 951                 }
 952                 show_one_commit(commit, no_name);
 953
 954                 if (shown_merge_point && --extra < 0)
 955                         break;
 956         }
 957         return 0;
 958 }