builtin/show-branch.c

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