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