builtin/show-branch.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "environment.h"
   4 #include "gettext.h"
   5 #include "hash.h"
   6 #include "hex.h"
   7 #include "pretty.h"
   8 #include "refs.h"
   9 #include "builtin.h"
  10 #include "color.h"
  11 #include "strvec.h"
  12 #include "object-name.h"
  13 #include "parse-options.h"
  14 #include "repository.h"
  15 #include "dir.h"
  16 #include "commit-slab.h"
  17 #include "date.h"
  18
  19 static const char* show_branch_usage[] = {
  20     N_("git show-branch [-a | --all] [-r | --remotes] [--topo-order | --date-order]\n"
  21        "                [--current] [--color[=<when>] | --no-color] [--sparse]\n"
  22        "                [--more=<n> | --list | --independent | --merge-base]\n"
  23        "                [--no-name | --sha1-name] [--topics]\n"
  24        "                [(<rev> | <glob>)...]"),
  25     N_("git show-branch (-g | --reflog)[=<n>[,<base>]] [--list] [<ref>]"),
  26     NULL
  27 };
  28
  29 static int showbranch_use_color = -1;
  30
  31 static struct strvec default_args = STRVEC_INIT;
  32
  33 /*
  34  * TODO: convert this use of commit->object.flags to commit-slab
  35  * instead to store a pointer to ref name directly. Then use the same
  36  * UNINTERESTING definition from revision.h here.
  37  */
  38 #define UNINTERESTING   01
  39
  40 #define REV_SHIFT        2
  41 #define MAX_REVS        (FLAG_BITS - REV_SHIFT) /* should not exceed bits_per_int - REV_SHIFT */
  42
  43 #define DEFAULT_REFLOG  4
  44
  45 static const char *get_color_code(int idx)
  46 {
  47         if (want_color(showbranch_use_color))
  48                 return column_colors_ansi[idx % column_colors_ansi_max];
  49         return "";
  50 }
  51
  52 static const char *get_color_reset_code(void)
  53 {
  54         if (want_color(showbranch_use_color))
  55                 return GIT_COLOR_RESET;
  56         return "";
  57 }
  58
  59 static struct commit *interesting(struct commit_list *list)
  60 {
  61         while (list) {
  62                 struct commit *commit = list->item;
  63                 list = list->next;
  64                 if (commit->object.flags & UNINTERESTING)
  65                         continue;
  66                 return commit;
  67         }
  68         return NULL;
  69 }
  70
  71 struct commit_name {
  72         const char *head_name; /* which head's ancestor? */
  73         int generation; /* how many parents away from head_name */
  74 };
  75
  76 define_commit_slab(commit_name_slab, struct commit_name *);
  77 static struct commit_name_slab name_slab;
  78
  79 static struct commit_name *commit_to_name(struct commit *commit)
  80 {
  81         return *commit_name_slab_at(&name_slab, commit);
  82 }
  83
  84
  85 /* Name the commit as nth generation ancestor of head_name;
  86  * we count only the first-parent relationship for naming purposes.
  87  */
  88 static void name_commit(struct commit *commit, const char *head_name, int nth)
  89 {
  90         struct commit_name *name;
  91
  92         name = *commit_name_slab_at(&name_slab, commit);
  93         if (!name) {
  94                 name = xmalloc(sizeof(*name));
  95                 *commit_name_slab_at(&name_slab, commit) = name;
  96         }
  97         name->head_name = head_name;
  98         name->generation = nth;
  99 }
 100
 101 /* Parent is the first parent of the commit.  We may name it
 102  * as (n+1)th generation ancestor of the same head_name as
 103  * commit is nth generation ancestor of, if that generation
 104  * number is better than the name it already has.
 105  */
 106 static void name_parent(struct commit *commit, struct commit *parent)
 107 {
 108         struct commit_name *commit_name = commit_to_name(commit);
 109         struct commit_name *parent_name = commit_to_name(parent);
 110         if (!commit_name)
 111                 return;
 112         if (!parent_name ||
 113             commit_name->generation + 1 < parent_name->generation)
 114                 name_commit(parent, commit_name->head_name,
 115                             commit_name->generation + 1);
 116 }
 117
 118 static int name_first_parent_chain(struct commit *c)
 119 {
 120         int i = 0;
 121         while (c) {
 122                 struct commit *p;
 123                 if (!commit_to_name(c))
 124                         break;
 125                 if (!c->parents)
 126                         break;
 127                 p = c->parents->item;
 128                 if (!commit_to_name(p)) {
 129                         name_parent(c, p);
 130                         i++;
 131                 }
 132                 else
 133                         break;
 134                 c = p;
 135         }
 136         return i;
 137 }
 138
 139 static void name_commits(struct commit_list *list,
 140                          struct commit **rev,
 141                          char **ref_name,
 142                          int num_rev)
 143 {
 144         struct commit_list *cl;
 145         struct commit *c;
 146         int i;
 147
 148         /* First give names to the given heads */
 149         for (cl = list; cl; cl = cl->next) {
 150                 c = cl->item;
 151                 if (commit_to_name(c))
 152                         continue;
 153                 for (i = 0; i < num_rev; i++) {
 154                         if (rev[i] == c) {
 155                                 name_commit(c, ref_name[i], 0);
 156                                 break;
 157                         }
 158                 }
 159         }
 160
 161         /* Then commits on the first parent ancestry chain */
 162         do {
 163                 i = 0;
 164                 for (cl = list; cl; cl = cl->next) {
 165                         i += name_first_parent_chain(cl->item);
 166                 }
 167         } while (i);
 168
 169         /* Finally, any unnamed commits */
 170         do {
 171                 i = 0;
 172                 for (cl = list; cl; cl = cl->next) {
 173                         struct commit_list *parents;
 174                         struct commit_name *n;
 175                         int nth;
 176                         c = cl->item;
 177                         if (!commit_to_name(c))
 178                                 continue;
 179                         n = commit_to_name(c);
 180                         parents = c->parents;
 181                         nth = 0;
 182                         while (parents) {
 183                                 struct commit *p = parents->item;
 184                                 struct strbuf newname = STRBUF_INIT;
 185                                 parents = parents->next;
 186                                 nth++;
 187                                 if (commit_to_name(p))
 188                                         continue;
 189                                 switch (n->generation) {
 190                                 case 0:
 191                                         strbuf_addstr(&newname, n->head_name);
 192                                         break;
 193                                 case 1:
 194                                         strbuf_addf(&newname, "%s^", n->head_name);
 195                                         break;
 196                                 default:
 197                                         strbuf_addf(&newname, "%s~%d",
 198                                                     n->head_name, n->generation);
 199                                         break;
 200                                 }
 201                                 if (nth == 1)
 202                                         strbuf_addch(&newname, '^');
 203                                 else
 204                                         strbuf_addf(&newname, "^%d", nth);
 205                                 name_commit(p, strbuf_detach(&newname, NULL), 0);
 206                                 i++;
 207                                 name_first_parent_chain(p);
 208                         }
 209                 }
 210         } while (i);
 211 }
 212
 213 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 214 {
 215         if (!commit->object.flags) {
 216                 commit_list_insert(commit, seen_p);
 217                 return 1;
 218         }
 219         return 0;
 220 }
 221
 222 static void join_revs(struct commit_list **list_p,
 223                       struct commit_list **seen_p,
 224                       int num_rev, int extra)
 225 {
 226         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 227         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 228
 229         while (*list_p) {
 230                 struct commit_list *parents;
 231                 int still_interesting = !!interesting(*list_p);
 232                 struct commit *commit = pop_commit(list_p);
 233                 int flags = commit->object.flags & all_mask;
 234
 235                 if (!still_interesting && extra <= 0)
 236                         break;
 237
 238                 mark_seen(commit, seen_p);
 239                 if ((flags & all_revs) == all_revs)
 240                         flags |= UNINTERESTING;
 241                 parents = commit->parents;
 242
 243                 while (parents) {
 244                         struct commit *p = parents->item;
 245                         int this_flag = p->object.flags;
 246                         parents = parents->next;
 247                         if ((this_flag & flags) == flags)
 248                                 continue;
 249                         repo_parse_commit(the_repository, p);
 250                         if (mark_seen(p, seen_p) && !still_interesting)
 251                                 extra--;
 252                         p->object.flags |= flags;
 253                         commit_list_insert_by_date(p, list_p);
 254                 }
 255         }
 256
 257         /*
 258          * Postprocess to complete well-poisoning.
 259          *
 260          * At this point we have all the commits we have seen in
 261          * seen_p list.  Mark anything that can be reached from
 262          * uninteresting commits not interesting.
 263          */
 264         for (;;) {
 265                 int changed = 0;
 266                 struct commit_list *s;
 267                 for (s = *seen_p; s; s = s->next) {
 268                         struct commit *c = s->item;
 269                         struct commit_list *parents;
 270
 271                         if (((c->object.flags & all_revs) != all_revs) &&
 272                             !(c->object.flags & UNINTERESTING))
 273                                 continue;
 274
 275                         /* The current commit is either a merge base or
 276                          * already uninteresting one.  Mark its parents
 277                          * as uninteresting commits _only_ if they are
 278                          * already parsed.  No reason to find new ones
 279                          * here.
 280                          */
 281                         parents = c->parents;
 282                         while (parents) {
 283                                 struct commit *p = parents->item;
 284                                 parents = parents->next;
 285                                 if (!(p->object.flags & UNINTERESTING)) {
 286                                         p->object.flags |= UNINTERESTING;
 287                                         changed = 1;
 288                                 }
 289                         }
 290                 }
 291                 if (!changed)
 292                         break;
 293         }
 294 }
 295
 296 static void show_one_commit(struct commit *commit, int no_name)
 297 {
 298         struct strbuf pretty = STRBUF_INIT;
 299         const char *pretty_str = "(unavailable)";
 300         struct commit_name *name = commit_to_name(commit);
 301
 302         if (commit->object.parsed) {
 303                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &pretty);
 304                 pretty_str = pretty.buf;
 305         }
 306         skip_prefix(pretty_str, "[PATCH] ", &pretty_str);
 307
 308         if (!no_name) {
 309                 if (name && name->head_name) {
 310                         printf("[%s", name->head_name);
 311                         if (name->generation) {
 312                                 if (name->generation == 1)
 313                                         printf("^");
 314                                 else
 315                                         printf("~%d", name->generation);
 316                         }
 317                         printf("] ");
 318                 }
 319                 else
 320                         printf("[%s] ",
 321                                repo_find_unique_abbrev(the_repository, &commit->object.oid,
 322                                                        DEFAULT_ABBREV));
 323         }
 324         puts(pretty_str);
 325         strbuf_release(&pretty);
 326 }
 327
 328 static char *ref_name[MAX_REVS + 1];
 329 static int ref_name_cnt;
 330
 331 static const char *find_digit_prefix(const char *s, int *v)
 332 {
 333         const char *p;
 334         int ver;
 335         char ch;
 336
 337         for (p = s, ver = 0;
 338              '0' <= (ch = *p) && ch <= '9';
 339              p++)
 340                 ver = ver * 10 + ch - '0';
 341         *v = ver;
 342         return p;
 343 }
 344
 345
 346 static int version_cmp(const char *a, const char *b)
 347 {
 348         while (1) {
 349                 int va, vb;
 350
 351                 a = find_digit_prefix(a, &va);
 352                 b = find_digit_prefix(b, &vb);
 353                 if (va != vb)
 354                         return va - vb;
 355
 356                 while (1) {
 357                         int ca = *a;
 358                         int cb = *b;
 359                         if ('0' <= ca && ca <= '9')
 360                                 ca = 0;
 361                         if ('0' <= cb && cb <= '9')
 362                                 cb = 0;
 363                         if (ca != cb)
 364                                 return ca - cb;
 365                         if (!ca)
 366                                 break;
 367                         a++;
 368                         b++;
 369                 }
 370                 if (!*a && !*b)
 371                         return 0;
 372         }
 373 }
 374
 375 static int compare_ref_name(const void *a_, const void *b_)
 376 {
 377         const char * const*a = a_, * const*b = b_;
 378         return version_cmp(*a, *b);
 379 }
 380
 381 static void sort_ref_range(int bottom, int top)
 382 {
 383         QSORT(ref_name + bottom, top - bottom, compare_ref_name);
 384 }
 385
 386 static int append_ref(const char *refname, const struct object_id *oid,
 387                       int allow_dups)
 388 {
 389         struct commit *commit = lookup_commit_reference_gently(the_repository,
 390                                                                oid, 1);
 391         int i;
 392
 393         if (!commit)
 394                 return 0;
 395
 396         if (!allow_dups) {
 397                 /* Avoid adding the same thing twice */
 398                 for (i = 0; i < ref_name_cnt; i++)
 399                         if (!strcmp(refname, ref_name[i]))
 400                                 return 0;
 401         }
 402         if (MAX_REVS <= ref_name_cnt) {
 403                 warning(Q_("ignoring %s; cannot handle more than %d ref",
 404                            "ignoring %s; cannot handle more than %d refs",
 405                            MAX_REVS), refname, MAX_REVS);
 406                 return 0;
 407         }
 408         ref_name[ref_name_cnt++] = xstrdup(refname);
 409         ref_name[ref_name_cnt] = NULL;
 410         return 0;
 411 }
 412
 413 static int append_head_ref(const char *refname, const struct object_id *oid,
 414                            int flag UNUSED, void *cb_data UNUSED)
 415 {
 416         struct object_id tmp;
 417         int ofs = 11;
 418         if (!starts_with(refname, "refs/heads/"))
 419                 return 0;
 420         /* If both heads/foo and tags/foo exists, get_sha1 would
 421          * get confused.
 422          */
 423         if (repo_get_oid(the_repository, refname + ofs, &tmp) || !oideq(&tmp, oid))
 424                 ofs = 5;
 425         return append_ref(refname + ofs, oid, 0);
 426 }
 427
 428 static int append_remote_ref(const char *refname, const struct object_id *oid,
 429                              int flag UNUSED, void *cb_data UNUSED)
 430 {
 431         struct object_id tmp;
 432         int ofs = 13;
 433         if (!starts_with(refname, "refs/remotes/"))
 434                 return 0;
 435         /* If both heads/foo and tags/foo exists, get_sha1 would
 436          * get confused.
 437          */
 438         if (repo_get_oid(the_repository, refname + ofs, &tmp) || !oideq(&tmp, oid))
 439                 ofs = 5;
 440         return append_ref(refname + ofs, oid, 0);
 441 }
 442
 443 static int append_tag_ref(const char *refname, const struct object_id *oid,
 444                           int flag UNUSED, void *cb_data UNUSED)
 445 {
 446         if (!starts_with(refname, "refs/tags/"))
 447                 return 0;
 448         return append_ref(refname + 5, oid, 0);
 449 }
 450
 451 static const char *match_ref_pattern = NULL;
 452 static int match_ref_slash = 0;
 453
 454 static int append_matching_ref(const char *refname, const struct object_id *oid,
 455                                int flag, void *cb_data)
 456 {
 457         /* we want to allow pattern hold/<asterisk> to show all
 458          * branches under refs/heads/hold/, and v0.99.9? to show
 459          * refs/tags/v0.99.9a and friends.
 460          */
 461         const char *tail;
 462         int slash = count_slashes(refname);
 463         for (tail = refname; *tail && match_ref_slash < slash; )
 464                 if (*tail++ == '/')
 465                         slash--;
 466         if (!*tail)
 467                 return 0;
 468         if (wildmatch(match_ref_pattern, tail, 0))
 469                 return 0;
 470         if (starts_with(refname, "refs/heads/"))
 471                 return append_head_ref(refname, oid, flag, cb_data);
 472         if (starts_with(refname, "refs/tags/"))
 473                 return append_tag_ref(refname, oid, flag, cb_data);
 474         return append_ref(refname, oid, 0);
 475 }
 476
 477 static void snarf_refs(int head, int remotes)
 478 {
 479         if (head) {
 480                 int orig_cnt = ref_name_cnt;
 481
 482                 for_each_ref(append_head_ref, NULL);
 483                 sort_ref_range(orig_cnt, ref_name_cnt);
 484         }
 485         if (remotes) {
 486                 int orig_cnt = ref_name_cnt;
 487
 488                 for_each_ref(append_remote_ref, NULL);
 489                 sort_ref_range(orig_cnt, ref_name_cnt);
 490         }
 491 }
 492
 493 static int rev_is_head(const char *head, const char *name)
 494 {
 495         if (!head)
 496                 return 0;
 497         skip_prefix(head, "refs/heads/", &head);
 498         if (!skip_prefix(name, "refs/heads/", &name))
 499                 skip_prefix(name, "heads/", &name);
 500         return !strcmp(head, name);
 501 }
 502
 503 static int show_merge_base(struct commit_list *seen, int num_rev)
 504 {
 505         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 506         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 507         int exit_status = 1;
 508
 509         while (seen) {
 510                 struct commit *commit = pop_commit(&seen);
 511                 int flags = commit->object.flags & all_mask;
 512                 if (!(flags & UNINTERESTING) &&
 513                     ((flags & all_revs) == all_revs)) {
 514                         puts(oid_to_hex(&commit->object.oid));
 515                         exit_status = 0;
 516                         commit->object.flags |= UNINTERESTING;
 517                 }
 518         }
 519         return exit_status;
 520 }
 521
 522 static int show_independent(struct commit **rev,
 523                             int num_rev,
 524                             unsigned int *rev_mask)
 525 {
 526         int i;
 527
 528         for (i = 0; i < num_rev; i++) {
 529                 struct commit *commit = rev[i];
 530                 unsigned int flag = rev_mask[i];
 531
 532                 if (commit->object.flags == flag)
 533                         puts(oid_to_hex(&commit->object.oid));
 534                 commit->object.flags |= UNINTERESTING;
 535         }
 536         return 0;
 537 }
 538
 539 static void append_one_rev(const char *av)
 540 {
 541         struct object_id revkey;
 542         if (!repo_get_oid(the_repository, av, &revkey)) {
 543                 append_ref(av, &revkey, 0);
 544                 return;
 545         }
 546         if (strpbrk(av, "*?[")) {
 547                 /* glob style match */
 548                 int saved_matches = ref_name_cnt;
 549
 550                 match_ref_pattern = av;
 551                 match_ref_slash = count_slashes(av);
 552                 for_each_ref(append_matching_ref, NULL);
 553                 if (saved_matches == ref_name_cnt &&
 554                     ref_name_cnt < MAX_REVS)
 555                         error(_("no matching refs with %s"), av);
 556                 sort_ref_range(saved_matches, ref_name_cnt);
 557                 return;
 558         }
 559         die("bad sha1 reference %s", av);
 560 }
 561
 562 static int git_show_branch_config(const char *var, const char *value, void *cb)
 563 {
 564         if (!strcmp(var, "showbranch.default")) {
 565                 if (!value)
 566                         return config_error_nonbool(var);
 567                 /*
 568                  * default_arg is now passed to parse_options(), so we need to
 569                  * mimic the real argv a bit better.
 570                  */
 571                 if (!default_args.nr)
 572                         strvec_push(&default_args, "show-branch");
 573                 strvec_push(&default_args, value);
 574                 return 0;
 575         }
 576
 577         if (!strcmp(var, "color.showbranch")) {
 578                 showbranch_use_color = git_config_colorbool(var, value);
 579                 return 0;
 580         }
 581
 582         return git_color_default_config(var, value, cb);
 583 }
 584
 585 static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
 586 {
 587         /* If the commit is tip of the named branches, do not
 588          * omit it.
 589          * Otherwise, if it is a merge that is reachable from only one
 590          * tip, it is not that interesting.
 591          */
 592         int i, flag, count;
 593         for (i = 0; i < n; i++)
 594                 if (rev[i] == commit)
 595                         return 0;
 596         flag = commit->object.flags;
 597         for (i = count = 0; i < n; i++) {
 598                 if (flag & (1u << (i + REV_SHIFT)))
 599                         count++;
 600         }
 601         if (count == 1)
 602                 return 1;
 603         return 0;
 604 }
 605
 606 static int reflog = 0;
 607
 608 static int parse_reflog_param(const struct option *opt, const char *arg,
 609                               int unset)
 610 {
 611         char *ep;
 612         const char **base = (const char **)opt->value;
 613         BUG_ON_OPT_NEG(unset);
 614         if (!arg)
 615                 arg = "";
 616         reflog = strtoul(arg, &ep, 10);
 617         if (*ep == ',')
 618                 *base = ep + 1;
 619         else if (*ep)
 620                 return error("unrecognized reflog param '%s'", arg);
 621         else
 622                 *base = NULL;
 623         if (reflog <= 0)
 624                 reflog = DEFAULT_REFLOG;
 625         return 0;
 626 }
 627
 628 int cmd_show_branch(int ac, const char **av, const char *prefix)
 629 {
 630         struct commit *rev[MAX_REVS], *commit;
 631         char *reflog_msg[MAX_REVS];
 632         struct commit_list *list = NULL, *seen = NULL;
 633         unsigned int rev_mask[MAX_REVS];
 634         int num_rev, i, extra = 0;
 635         int all_heads = 0, all_remotes = 0;
 636         int all_mask, all_revs;
 637         enum rev_sort_order sort_order = REV_SORT_IN_GRAPH_ORDER;
 638         char *head;
 639         struct object_id head_oid;
 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                 OPT_CALLBACK_F('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_NONEG,
 685                             parse_reflog_param),
 686                 OPT_END()
 687         };
 688
 689         init_commit_name_slab(&name_slab);
 690
 691         git_config(git_show_branch_config, NULL);
 692
 693         /* If nothing is specified, try the default first */
 694         if (ac == 1 && default_args.nr) {
 695                 ac = default_args.nr;
 696                 av = default_args.v;
 697         }
 698
 699         ac = parse_options(ac, av, prefix, builtin_show_branch_options,
 700                            show_branch_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 701         if (all_heads)
 702                 all_remotes = 1;
 703
 704         if (extra || reflog) {
 705                 /* "listing" mode is incompatible with
 706                  * independent nor merge-base modes.
 707                  */
 708                 if (independent || merge_base)
 709                         usage_with_options(show_branch_usage,
 710                                            builtin_show_branch_options);
 711                 if (reflog && ((0 < extra) || all_heads || all_remotes))
 712                         /*
 713                          * Asking for --more in reflog mode does not
 714                          * make sense.  --list is Ok.
 715                          *
 716                          * Also --all and --remotes do not make sense either.
 717                          */
 718                         die(_("options '%s' and '%s' cannot be used together"), "--reflog",
 719                                 "--all/--remotes/--independent/--merge-base");
 720         }
 721
 722         if (with_current_branch && reflog)
 723                 die(_("options '%s' and '%s' cannot be used together"),
 724                     "--reflog", "--current");
 725
 726         /* If nothing is specified, show all branches by default */
 727         if (ac <= topics && all_heads + all_remotes == 0)
 728                 all_heads = 1;
 729
 730         if (reflog) {
 731                 struct object_id oid;
 732                 char *ref;
 733                 int base = 0;
 734                 unsigned int flags = 0;
 735
 736                 if (ac == 0) {
 737                         static const char *fake_av[2];
 738
 739                         fake_av[0] = resolve_refdup("HEAD",
 740                                                     RESOLVE_REF_READING, &oid,
 741                                                     NULL);
 742                         fake_av[1] = NULL;
 743                         av = fake_av;
 744                         ac = 1;
 745                         if (!*av)
 746                                 die(_("no branches given, and HEAD is not valid"));
 747                 }
 748                 if (ac != 1)
 749                         die(_("--reflog option needs one branch name"));
 750
 751                 if (MAX_REVS < reflog)
 752                         die(Q_("only %d entry can be shown at one time.",
 753                                "only %d entries can be shown at one time.",
 754                                MAX_REVS), MAX_REVS);
 755                 if (!repo_dwim_ref(the_repository, *av, strlen(*av), &oid,
 756                                    &ref, 0))
 757                         die(_("no such ref %s"), *av);
 758
 759                 /* Has the base been specified? */
 760                 if (reflog_base) {
 761                         char *ep;
 762                         base = strtoul(reflog_base, &ep, 10);
 763                         if (*ep) {
 764                                 /* Ah, that is a date spec... */
 765                                 timestamp_t at;
 766                                 at = approxidate(reflog_base);
 767                                 read_ref_at(get_main_ref_store(the_repository),
 768                                             ref, flags, at, -1, &oid, NULL,
 769                                             NULL, NULL, &base);
 770                         }
 771                 }
 772
 773                 for (i = 0; i < reflog; i++) {
 774                         char *logmsg;
 775                         char *nth_desc;
 776                         const char *msg;
 777                         char *end;
 778                         timestamp_t timestamp;
 779                         int tz;
 780
 781                         if (read_ref_at(get_main_ref_store(the_repository),
 782                                         ref, flags, 0, base + i, &oid, &logmsg,
 783                                         &timestamp, &tz, NULL)) {
 784                                 reflog = i;
 785                                 break;
 786                         }
 787
 788                         end = strchr(logmsg, '\n');
 789                         if (end)
 790                                 *end = '\0';
 791
 792                         msg = (*logmsg == '\0') ? "(none)" : logmsg;
 793                         reflog_msg[i] = xstrfmt("(%s) %s",
 794                                                 show_date(timestamp, tz,
 795                                                           DATE_MODE(RELATIVE)),
 796                                                 msg);
 797                         free(logmsg);
 798
 799                         nth_desc = xstrfmt("%s@{%d}", *av, base+i);
 800                         append_ref(nth_desc, &oid, 1);
 801                         free(nth_desc);
 802                 }
 803                 free(ref);
 804         }
 805         else {
 806                 while (0 < ac) {
 807                         append_one_rev(*av);
 808                         ac--; av++;
 809                 }
 810                 if (all_heads + all_remotes)
 811                         snarf_refs(all_heads, all_remotes);
 812         }
 813
 814         head = resolve_refdup("HEAD", RESOLVE_REF_READING,
 815                               &head_oid, NULL);
 816
 817         if (with_current_branch && head) {
 818                 int has_head = 0;
 819                 for (i = 0; !has_head && i < ref_name_cnt; i++) {
 820                         /* We are only interested in adding the branch
 821                          * HEAD points at.
 822                          */
 823                         if (rev_is_head(head, ref_name[i]))
 824                                 has_head++;
 825                 }
 826                 if (!has_head) {
 827                         const char *name = head;
 828                         skip_prefix(name, "refs/heads/", &name);
 829                         append_one_rev(name);
 830                 }
 831         }
 832
 833         if (!ref_name_cnt) {
 834                 fprintf(stderr, "No revs to be shown.\n");
 835                 exit(0);
 836         }
 837
 838         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 839                 struct object_id revkey;
 840                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 841
 842                 if (MAX_REVS <= num_rev)
 843                         die(Q_("cannot handle more than %d rev.",
 844                                "cannot handle more than %d revs.",
 845                                MAX_REVS), MAX_REVS);
 846                 if (repo_get_oid(the_repository, ref_name[num_rev], &revkey))
 847                         die(_("'%s' is not a valid ref."), ref_name[num_rev]);
 848                 commit = lookup_commit_reference(the_repository, &revkey);
 849                 if (!commit)
 850                         die(_("cannot find commit %s (%s)"),
 851                             ref_name[num_rev], oid_to_hex(&revkey));
 852                 repo_parse_commit(the_repository, commit);
 853                 mark_seen(commit, &seen);
 854
 855                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 856                  * and so on.  REV_SHIFT bits from bit 0 are used for
 857                  * internal bookkeeping.
 858                  */
 859                 commit->object.flags |= flag;
 860                 if (commit->object.flags == flag)
 861                         commit_list_insert_by_date(commit, &list);
 862                 rev[num_rev] = commit;
 863         }
 864         for (i = 0; i < num_rev; i++)
 865                 rev_mask[i] = rev[i]->object.flags;
 866
 867         if (0 <= extra)
 868                 join_revs(&list, &seen, num_rev, extra);
 869
 870         commit_list_sort_by_date(&seen);
 871
 872         if (merge_base)
 873                 return show_merge_base(seen, num_rev);
 874
 875         if (independent)
 876                 return show_independent(rev, num_rev, rev_mask);
 877
 878         /* Show list; --more=-1 means list-only */
 879         if (1 < num_rev || extra < 0) {
 880                 for (i = 0; i < num_rev; i++) {
 881                         int j;
 882                         int is_head = rev_is_head(head, ref_name[i]) &&
 883                                       oideq(&head_oid, &rev[i]->object.oid);
 884                         if (extra < 0)
 885                                 printf("%c [%s] ",
 886                                        is_head ? '*' : ' ', ref_name[i]);
 887                         else {
 888                                 for (j = 0; j < i; j++)
 889                                         putchar(' ');
 890                                 printf("%s%c%s [%s] ",
 891                                        get_color_code(i),
 892                                        is_head ? '*' : '!',
 893                                        get_color_reset_code(), ref_name[i]);
 894                         }
 895
 896                         if (!reflog) {
 897                                 /* header lines never need name */
 898                                 show_one_commit(rev[i], 1);
 899                         }
 900                         else
 901                                 puts(reflog_msg[i]);
 902
 903                         if (is_head)
 904                                 head_at = i;
 905                 }
 906                 if (0 <= extra) {
 907                         for (i = 0; i < num_rev; i++)
 908                                 putchar('-');
 909                         putchar('\n');
 910                 }
 911         }
 912         if (extra < 0)
 913                 exit(0);
 914
 915         /* Sort topologically */
 916         sort_in_topological_order(&seen, sort_order);
 917
 918         /* Give names to commits */
 919         if (!sha1_name && !no_name)
 920                 name_commits(seen, rev, ref_name, num_rev);
 921
 922         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 923         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 924
 925         while (seen) {
 926                 struct commit *commit = pop_commit(&seen);
 927                 int this_flag = commit->object.flags;
 928                 int is_merge_point = ((this_flag & all_revs) == all_revs);
 929
 930                 shown_merge_point |= is_merge_point;
 931
 932                 if (1 < num_rev) {
 933                         int is_merge = !!(commit->parents &&
 934                                           commit->parents->next);
 935                         if (topics &&
 936                             !is_merge_point &&
 937                             (this_flag & (1u << REV_SHIFT)))
 938                                 continue;
 939                         if (dense && is_merge &&
 940                             omit_in_dense(commit, rev, num_rev))
 941                                 continue;
 942                         for (i = 0; i < num_rev; i++) {
 943                                 int mark;
 944                                 if (!(this_flag & (1u << (i + REV_SHIFT))))
 945                                         mark = ' ';
 946                                 else if (is_merge)
 947                                         mark = '-';
 948                                 else if (i == head_at)
 949                                         mark = '*';
 950                                 else
 951                                         mark = '+';
 952                                 if (mark == ' ')
 953                                         putchar(mark);
 954                                 else
 955                                         printf("%s%c%s",
 956                                                get_color_code(i),
 957                                                mark, get_color_reset_code());
 958                         }
 959                         putchar(' ');
 960                 }
 961                 show_one_commit(commit, no_name);
 962
 963                 if (shown_merge_point && --extra < 0)
 964                         break;
 965         }
 966         free(head);
 967         return 0;
 968 }