show-branch.c

   1 #include <stdlib.h>
   2 #include "cache.h"
   3 #include "commit.h"
   4 #include "refs.h"
   5
   6 static const char show_branch_usage[] =
   7 "git-show-branch [--all] [--heads] [--tags] [--more=count | --list | --independent | --merge-base ] [<refs>...]";
   8
   9 #define UNINTERESTING   01
  10
  11 #define REV_SHIFT        2
  12 #define MAX_REVS        29 /* should not exceed bits_per_int - REV_SHIFT */
  13
  14 static struct commit *interesting(struct commit_list *list)
  15 {
  16         while (list) {
  17                 struct commit *commit = list->item;
  18                 list = list->next;
  19                 if (commit->object.flags & UNINTERESTING)
  20                         continue;
  21                 return commit;
  22         }
  23         return NULL;
  24 }
  25
  26 static struct commit *pop_one_commit(struct commit_list **list_p)
  27 {
  28         struct commit *commit;
  29         struct commit_list *list;
  30         list = *list_p;
  31         commit = list->item;
  32         *list_p = list->next;
  33         free(list);
  34         return commit;
  35 }
  36
  37 struct commit_name {
  38         const char *head_name; /* which head's ancestor? */
  39         int generation; /* how many parents away from head_name */
  40 };
  41
  42 /* Name the commit as nth generation ancestor of head_name;
  43  * we count only the first-parent relationship for naming purposes.
  44  */
  45 static void name_commit(struct commit *commit, const char *head_name, int nth)
  46 {
  47         struct commit_name *name;
  48         if (!commit->object.util)
  49                 commit->object.util = xmalloc(sizeof(struct commit_name));
  50         name = commit->object.util;
  51         name->head_name = head_name;
  52         name->generation = nth;
  53 }
  54
  55 /* Parent is the first parent of the commit.  We may name it
  56  * as (n+1)th generation ancestor of the same head_name as
  57  * commit is nth generation ancestore of, if that generation
  58  * number is better than the name it already has.
  59  */
  60 static void name_parent(struct commit *commit, struct commit *parent)
  61 {
  62         struct commit_name *commit_name = commit->object.util;
  63         struct commit_name *parent_name = parent->object.util;
  64         if (!commit_name)
  65                 return;
  66         if (!parent_name ||
  67             commit_name->generation + 1 < parent_name->generation)
  68                 name_commit(parent, commit_name->head_name,
  69                             commit_name->generation + 1);
  70 }
  71
  72 static int name_first_parent_chain(struct commit *c)
  73 {
  74         int i = 0;
  75         while (c) {
  76                 struct commit *p;
  77                 if (!c->object.util)
  78                         break;
  79                 if (!c->parents)
  80                         break;
  81                 p = c->parents->item;
  82                 if (!p->object.util) {
  83                         name_parent(c, p);
  84                         i++;
  85                 }
  86                 c = p;
  87         }
  88         return i;
  89 }
  90
  91 static void name_commits(struct commit_list *list,
  92                          struct commit **rev,
  93                          char **ref_name,
  94                          int num_rev)
  95 {
  96         struct commit_list *cl;
  97         struct commit *c;
  98         int i;
  99
 100         /* First give names to the given heads */
 101         for (cl = list; cl; cl = cl->next) {
 102                 c = cl->item;
 103                 if (c->object.util)
 104                         continue;
 105                 for (i = 0; i < num_rev; i++) {
 106                         if (rev[i] == c) {
 107                                 name_commit(c, ref_name[i], 0);
 108                                 break;
 109                         }
 110                 }
 111         }
 112
 113         /* Then commits on the first parent ancestry chain */
 114         do {
 115                 i = 0;
 116                 for (cl = list; cl; cl = cl->next) {
 117                         i += name_first_parent_chain(cl->item);
 118                 }
 119         } while (i);
 120
 121         /* Finally, any unnamed commits */
 122         do {
 123                 i = 0;
 124                 for (cl = list; cl; cl = cl->next) {
 125                         struct commit_list *parents;
 126                         struct commit_name *n;
 127                         int nth;
 128                         c = cl->item;
 129                         if (!c->object.util)
 130                                 continue;
 131                         n = c->object.util;
 132                         parents = c->parents;
 133                         nth = 0;
 134                         while (parents) {
 135                                 struct commit *p = parents->item;
 136                                 char newname[1000], *en;
 137                                 parents = parents->next;
 138                                 nth++;
 139                                 if (p->object.util)
 140                                         continue;
 141                                 en = newname;
 142                                 switch (n->generation) {
 143                                 case 0:
 144                                         en += sprintf(en, "%s", n->head_name);
 145                                         break;
 146                                 case 1:
 147                                         en += sprintf(en, "%s^", n->head_name);
 148                                         break;
 149                                 default:
 150                                         en += sprintf(en, "%s~%d",
 151                                                 n->head_name, n->generation);
 152                                         break;
 153                                 }
 154                                 if (nth == 1)
 155                                         en += sprintf(en, "^");
 156                                 else
 157                                         en += sprintf(en, "^%d", nth);
 158                                 name_commit(p, strdup(newname), 0);
 159                                 i++;
 160                                 name_first_parent_chain(p);
 161                         }
 162                 }
 163         } while (i);
 164 }
 165
 166 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 167 {
 168         if (!commit->object.flags) {
 169                 insert_by_date(commit, seen_p);
 170                 return 1;
 171         }
 172         return 0;
 173 }
 174
 175 static void join_revs(struct commit_list **list_p,
 176                       struct commit_list **seen_p,
 177                       int num_rev, int extra)
 178 {
 179         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 180         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 181
 182         while (*list_p) {
 183                 struct commit_list *parents;
 184                 int still_interesting = !!interesting(*list_p);
 185                 struct commit *commit = pop_one_commit(list_p);
 186                 int flags = commit->object.flags & all_mask;
 187
 188                 if (!still_interesting && extra <= 0)
 189                         break;
 190
 191                 mark_seen(commit, seen_p);
 192                 if ((flags & all_revs) == all_revs)
 193                         flags |= UNINTERESTING;
 194                 parents = commit->parents;
 195
 196                 while (parents) {
 197                         struct commit *p = parents->item;
 198                         int this_flag = p->object.flags;
 199                         parents = parents->next;
 200                         if ((this_flag & flags) == flags)
 201                                 continue;
 202                         if (!p->object.parsed)
 203                                 parse_commit(p);
 204                         if (mark_seen(p, seen_p) && !still_interesting)
 205                                 extra--;
 206                         p->object.flags |= flags;
 207                         insert_by_date(p, list_p);
 208                 }
 209         }
 210
 211         /*
 212          * Postprocess to complete well-poisoning.
 213          *
 214          * At this point we have all the commits we have seen in
 215          * seen_p list (which happens to be sorted chronologically but
 216          * it does not really matter).  Mark anything that can be
 217          * reached from uninteresting commits not interesting.
 218          */
 219         for (;;) {
 220                 int changed = 0;
 221                 struct commit_list *s;
 222                 for (s = *seen_p; s; s = s->next) {
 223                         struct commit *c = s->item;
 224                         struct commit_list *parents;
 225
 226                         if (((c->object.flags & all_revs) != all_revs) &&
 227                             !(c->object.flags & UNINTERESTING))
 228                                 continue;
 229
 230                         /* The current commit is either a merge base or
 231                          * already uninteresting one.  Mark its parents
 232                          * as uninteresting commits _only_ if they are
 233                          * already parsed.  No reason to find new ones
 234                          * here.
 235                          */
 236                         parents = c->parents;
 237                         while (parents) {
 238                                 struct commit *p = parents->item;
 239                                 parents = parents->next;
 240                                 if (!(p->object.flags & UNINTERESTING)) {
 241                                         p->object.flags |= UNINTERESTING;
 242                                         changed = 1;
 243                                 }
 244                         }
 245                 }
 246                 if (!changed)
 247                         break;
 248         }
 249 }
 250
 251 static void show_one_commit(struct commit *commit, int no_name)
 252 {
 253         char pretty[256], *cp;
 254         struct commit_name *name = commit->object.util;
 255         if (commit->object.parsed)
 256                 pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
 257                                     pretty, sizeof(pretty));
 258         else
 259                 strcpy(pretty, "(unavailable)");
 260         if (!strncmp(pretty, "[PATCH] ", 8))
 261                 cp = pretty + 8;
 262         else
 263                 cp = pretty;
 264
 265         if (!no_name) {
 266                 if (name && name->head_name) {
 267                         printf("[%s", name->head_name);
 268                         if (name->generation) {
 269                                 if (name->generation == 1)
 270                                         printf("^");
 271                                 else
 272                                         printf("~%d", name->generation);
 273                         }
 274                         printf("] ");
 275                 }
 276                 else
 277                         printf("[%s] ",
 278                                find_unique_abbrev(commit->object.sha1, 7));
 279         }
 280         puts(cp);
 281 }
 282
 283 static char *ref_name[MAX_REVS + 1];
 284 static int ref_name_cnt;
 285
 286 static int compare_ref_name(const void *a_, const void *b_)
 287 {
 288         const char * const*a = a_, * const*b = b_;
 289         return strcmp(*a, *b);
 290 }
 291
 292 static void sort_ref_range(int bottom, int top)
 293 {
 294         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 295               compare_ref_name);
 296 }
 297
 298 static int append_ref(const char *refname, const unsigned char *sha1)
 299 {
 300         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 301         if (!commit)
 302                 return 0;
 303         if (MAX_REVS <= ref_name_cnt) {
 304                 fprintf(stderr, "warning: ignoring %s; "
 305                         "cannot handle more than %d refs",
 306                         refname, MAX_REVS);
 307                 return 0;
 308         }
 309         ref_name[ref_name_cnt++] = strdup(refname);
 310         ref_name[ref_name_cnt] = NULL;
 311         return 0;
 312 }
 313
 314 static int append_head_ref(const char *refname, const unsigned char *sha1)
 315 {
 316         if (strncmp(refname, "refs/heads/", 11))
 317                 return 0;
 318         return append_ref(refname + 11, sha1);
 319 }
 320
 321 static int append_tag_ref(const char *refname, const unsigned char *sha1)
 322 {
 323         if (strncmp(refname, "refs/tags/", 10))
 324                 return 0;
 325         return append_ref(refname + 5, sha1);
 326 }
 327
 328 static void snarf_refs(int head, int tag)
 329 {
 330         if (head) {
 331                 int orig_cnt = ref_name_cnt;
 332                 for_each_ref(append_head_ref);
 333                 sort_ref_range(orig_cnt, ref_name_cnt);
 334         }
 335         if (tag) {
 336                 int orig_cnt = ref_name_cnt;
 337                 for_each_ref(append_tag_ref);
 338                 sort_ref_range(orig_cnt, ref_name_cnt);
 339         }
 340 }
 341
 342 static int rev_is_head(char *head_path, int headlen,
 343                        char *name,
 344                        unsigned char *head_sha1, unsigned char *sha1)
 345 {
 346         int namelen;
 347         if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
 348                 return 0;
 349         namelen = strlen(name);
 350         if ((headlen < namelen) ||
 351             memcmp(head_path + headlen - namelen, name, namelen))
 352                 return 0;
 353         if (headlen == namelen ||
 354             head_path[headlen - namelen - 1] == '/')
 355                 return 1;
 356         return 0;
 357 }
 358
 359 static int show_merge_base(struct commit_list *seen, int num_rev)
 360 {
 361         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 362         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 363         int exit_status = 1;
 364
 365         while (seen) {
 366                 struct commit *commit = pop_one_commit(&seen);
 367                 int flags = commit->object.flags & all_mask;
 368                 if (!(flags & UNINTERESTING) &&
 369                     ((flags & all_revs) == all_revs)) {
 370                         puts(sha1_to_hex(commit->object.sha1));
 371                         exit_status = 0;
 372                         commit->object.flags |= UNINTERESTING;
 373                 }
 374         }
 375         return exit_status;
 376 }
 377
 378 static int show_independent(struct commit **rev,
 379                             int num_rev,
 380                             char **ref_name,
 381                             unsigned int *rev_mask)
 382 {
 383         int i;
 384
 385         for (i = 0; i < num_rev; i++) {
 386                 struct commit *commit = rev[i];
 387                 unsigned int flag = rev_mask[i];
 388
 389                 if (commit->object.flags == flag)
 390                         puts(sha1_to_hex(commit->object.sha1));
 391                 commit->object.flags |= UNINTERESTING;
 392         }
 393         return 0;
 394 }
 395
 396 int main(int ac, char **av)
 397 {
 398         struct commit *rev[MAX_REVS], *commit;
 399         struct commit_list *list = NULL, *seen = NULL;
 400         unsigned int rev_mask[MAX_REVS];
 401         int num_rev, i, extra = 0;
 402         int all_heads = 0, all_tags = 0;
 403         int all_mask, all_revs;
 404         char head_path[128];
 405         const char *head_path_p;
 406         int head_path_len;
 407         unsigned char head_sha1[20];
 408         int merge_base = 0;
 409         int independent = 0;
 410         int no_name = 0;
 411         int sha1_name = 0;
 412         int shown_merge_point = 0;
 413         int topo_order = 0;
 414
 415         setup_git_directory();
 416
 417         while (1 < ac && av[1][0] == '-') {
 418                 char *arg = av[1];
 419                 if (!strcmp(arg, "--all"))
 420                         all_heads = all_tags = 1;
 421                 else if (!strcmp(arg, "--heads"))
 422                         all_heads = 1;
 423                 else if (!strcmp(arg, "--tags"))
 424                         all_tags = 1;
 425                 else if (!strcmp(arg, "--more"))
 426                         extra = 1;
 427                 else if (!strcmp(arg, "--list"))
 428                         extra = -1;
 429                 else if (!strcmp(arg, "--no-name"))
 430                         no_name = 1;
 431                 else if (!strcmp(arg, "--sha1-name"))
 432                         sha1_name = 1;
 433                 else if (!strncmp(arg, "--more=", 7))
 434                         extra = atoi(arg + 7);
 435                 else if (!strcmp(arg, "--merge-base"))
 436                         merge_base = 1;
 437                 else if (!strcmp(arg, "--independent"))
 438                         independent = 1;
 439                 else if (!strcmp(arg, "--topo-order"))
 440                         topo_order = 1;
 441                 else
 442                         usage(show_branch_usage);
 443                 ac--; av++;
 444         }
 445         ac--; av++;
 446
 447         /* Only one of these is allowed */
 448         if (1 < independent + merge_base + (extra != 0))
 449                 usage(show_branch_usage);
 450
 451         if (all_heads + all_tags)
 452                 snarf_refs(all_heads, all_tags);
 453
 454         while (0 < ac) {
 455                 unsigned char revkey[20];
 456                 if (get_sha1(*av, revkey))
 457                         die("bad sha1 reference %s", *av);
 458                 append_ref(*av, revkey);
 459                 ac--; av++;
 460         }
 461
 462         /* If still no revs, then add heads */
 463         if (!ref_name_cnt)
 464                 snarf_refs(1, 0);
 465
 466         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 467                 unsigned char revkey[20];
 468                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 469
 470                 if (MAX_REVS <= num_rev)
 471                         die("cannot handle more than %d revs.", MAX_REVS);
 472                 if (get_sha1(ref_name[num_rev], revkey))
 473                         usage(show_branch_usage);
 474                 commit = lookup_commit_reference(revkey);
 475                 if (!commit)
 476                         die("cannot find commit %s (%s)",
 477                             ref_name[num_rev], revkey);
 478                 parse_commit(commit);
 479                 mark_seen(commit, &seen);
 480
 481                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 482                  * and so on.  REV_SHIFT bits from bit 0 are used for
 483                  * internal bookkeeping.
 484                  */
 485                 commit->object.flags |= flag;
 486                 if (commit->object.flags == flag)
 487                         insert_by_date(commit, &list);
 488                 rev[num_rev] = commit;
 489         }
 490         for (i = 0; i < num_rev; i++)
 491                 rev_mask[i] = rev[i]->object.flags;
 492
 493         if (0 <= extra)
 494                 join_revs(&list, &seen, num_rev, extra);
 495
 496         head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1);
 497         if (head_path_p) {
 498                 head_path_len = strlen(head_path_p);
 499                 memcpy(head_path, head_path_p, head_path_len + 1);
 500         }
 501         else {
 502                 head_path_len = 0;
 503                 head_path[0] = 0;
 504         }
 505
 506         if (merge_base)
 507                 return show_merge_base(seen, num_rev);
 508
 509         if (independent)
 510                 return show_independent(rev, num_rev, ref_name, rev_mask);
 511
 512         /* Show list; --more=-1 means list-only */
 513         if (1 < num_rev || extra < 0) {
 514                 for (i = 0; i < num_rev; i++) {
 515                         int j;
 516                         int is_head = rev_is_head(head_path,
 517                                                   head_path_len,
 518                                                   ref_name[i],
 519                                                   head_sha1,
 520                                                   rev[i]->object.sha1);
 521                         if (extra < 0)
 522                                 printf("%c [%s] ",
 523                                        is_head ? '*' : ' ', ref_name[i]);
 524                         else {
 525                                 for (j = 0; j < i; j++)
 526                                         putchar(' ');
 527                                 printf("%c [%s] ",
 528                                        is_head ? '*' : '!', ref_name[i]);
 529                         }
 530                         /* header lines never need name */
 531                         show_one_commit(rev[i], 1);
 532                 }
 533                 if (0 <= extra) {
 534                         for (i = 0; i < num_rev; i++)
 535                                 putchar('-');
 536                         putchar('\n');
 537                 }
 538         }
 539         if (extra < 0)
 540                 exit(0);
 541
 542         /* Sort topologically */
 543         if (topo_order)
 544                 sort_in_topological_order(&seen);
 545
 546         /* Give names to commits */
 547         if (!sha1_name && !no_name)
 548                 name_commits(seen, rev, ref_name, num_rev);
 549
 550         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 551         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 552
 553         while (seen) {
 554                 struct commit *commit = pop_one_commit(&seen);
 555                 int this_flag = commit->object.flags;
 556
 557                 shown_merge_point |= ((this_flag & all_revs) == all_revs);
 558
 559                 if (1 < num_rev) {
 560                         for (i = 0; i < num_rev; i++)
 561                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
 562                                         ? '+' : ' ');
 563                         putchar(' ');
 564                 }
 565                 show_one_commit(commit, no_name);
 566
 567                 if (shown_merge_point && --extra < 0)
 568                         break;
 569         }
 570         return 0;
 571 }