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                 struct commit *commit = pop_one_commit(list_p);
 185                 int flags = commit->object.flags & all_mask;
 186                 int still_interesting = !!interesting(*list_p);
 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                         parse_commit(p);
 203                         if (mark_seen(p, seen_p) && !still_interesting)
 204                                 extra--;
 205                         p->object.flags |= flags;
 206                         insert_by_date(p, list_p);
 207                 }
 208         }
 209 }
 210
 211 static void show_one_commit(struct commit *commit, int no_name)
 212 {
 213         char pretty[128], *cp;
 214         struct commit_name *name = commit->object.util;
 215         if (commit->object.parsed)
 216                 pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
 217                                     pretty, sizeof(pretty));
 218         else
 219                 strcpy(pretty, "(unavailable)");
 220         if (!strncmp(pretty, "[PATCH] ", 8))
 221                 cp = pretty + 8;
 222         else
 223                 cp = pretty;
 224
 225         if (!no_name) {
 226                 if (name && name->head_name) {
 227                         printf("[%s", name->head_name);
 228                         if (name->generation) {
 229                                 if (name->generation == 1)
 230                                         printf("^");
 231                                 else
 232                                         printf("~%d", name->generation);
 233                         }
 234                         printf("] ");
 235                 }
 236                 else
 237                         printf("[%s] ",
 238                                find_unique_abbrev(commit->object.sha1, 7));
 239         }
 240         puts(cp);
 241 }
 242
 243 static char *ref_name[MAX_REVS + 1];
 244 static int ref_name_cnt;
 245
 246 static int compare_ref_name(const void *a_, const void *b_)
 247 {
 248         const char * const*a = a_, * const*b = b_;
 249         return strcmp(*a, *b);
 250 }
 251
 252 static void sort_ref_range(int bottom, int top)
 253 {
 254         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 255               compare_ref_name);
 256 }
 257
 258 static int append_ref(const char *refname, const unsigned char *sha1)
 259 {
 260         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 261         if (!commit)
 262                 return 0;
 263         if (MAX_REVS <= ref_name_cnt) {
 264                 fprintf(stderr, "warning: ignoring %s; "
 265                         "cannot handle more than %d refs",
 266                         refname, MAX_REVS);
 267                 return 0;
 268         }
 269         ref_name[ref_name_cnt++] = strdup(refname);
 270         ref_name[ref_name_cnt] = NULL;
 271         return 0;
 272 }
 273
 274 static int append_head_ref(const char *refname, const unsigned char *sha1)
 275 {
 276         if (strncmp(refname, "refs/heads/", 11))
 277                 return 0;
 278         return append_ref(refname + 11, sha1);
 279 }
 280
 281 static int append_tag_ref(const char *refname, const unsigned char *sha1)
 282 {
 283         if (strncmp(refname, "refs/tags/", 10))
 284                 return 0;
 285         return append_ref(refname + 5, sha1);
 286 }
 287
 288 static void snarf_refs(int head, int tag)
 289 {
 290         if (head) {
 291                 int orig_cnt = ref_name_cnt;
 292                 for_each_ref(append_head_ref);
 293                 sort_ref_range(orig_cnt, ref_name_cnt);
 294         }
 295         if (tag) {
 296                 int orig_cnt = ref_name_cnt;
 297                 for_each_ref(append_tag_ref);
 298                 sort_ref_range(orig_cnt, ref_name_cnt);
 299         }
 300 }
 301
 302 static int rev_is_head(char *head_path, int headlen,
 303                        char *name,
 304                        unsigned char *head_sha1, unsigned char *sha1)
 305 {
 306         int namelen;
 307         if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
 308                 return 0;
 309         namelen = strlen(name);
 310         if ((headlen < namelen) ||
 311             memcmp(head_path + headlen - namelen, name, namelen))
 312                 return 0;
 313         if (headlen == namelen ||
 314             head_path[headlen - namelen - 1] == '/')
 315                 return 1;
 316         return 0;
 317 }
 318
 319 static int show_merge_base(struct commit_list *seen, int num_rev)
 320 {
 321         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 322         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 323         int exit_status = 1;
 324
 325         while (seen) {
 326                 struct commit *commit = pop_one_commit(&seen);
 327                 int flags = commit->object.flags & all_mask;
 328                 if (!(flags & UNINTERESTING) &&
 329                     ((flags & all_revs) == all_revs)) {
 330                         puts(sha1_to_hex(commit->object.sha1));
 331                         exit_status = 0;
 332                         commit->object.flags |= UNINTERESTING;
 333                 }
 334         }
 335         return exit_status;
 336 }
 337
 338 static int show_independent(struct commit **rev,
 339                             int num_rev,
 340                             char **ref_name,
 341                             unsigned int *rev_mask)
 342 {
 343         int i;
 344
 345         for (i = 0; i < num_rev; i++) {
 346                 struct commit *commit = rev[i];
 347                 unsigned int flag = rev_mask[i];
 348
 349                 if (commit->object.flags == flag)
 350                         puts(sha1_to_hex(commit->object.sha1));
 351                 commit->object.flags |= UNINTERESTING;
 352         }
 353         return 0;
 354 }
 355
 356 int main(int ac, char **av)
 357 {
 358         struct commit *rev[MAX_REVS], *commit;
 359         struct commit_list *list = NULL, *seen = NULL;
 360         unsigned int rev_mask[MAX_REVS];
 361         int num_rev, i, extra = 0;
 362         int all_heads = 0, all_tags = 0;
 363         int all_mask, all_revs, shown_merge_point;
 364         char head_path[128];
 365         const char *head_path_p;
 366         int head_path_len;
 367         unsigned char head_sha1[20];
 368         int merge_base = 0;
 369         int independent = 0;
 370         int no_name = 0;
 371         int sha1_name = 0;
 372
 373         setup_git_directory();
 374
 375         while (1 < ac && av[1][0] == '-') {
 376                 char *arg = av[1];
 377                 if (!strcmp(arg, "--all"))
 378                         all_heads = all_tags = 1;
 379                 else if (!strcmp(arg, "--heads"))
 380                         all_heads = 1;
 381                 else if (!strcmp(arg, "--tags"))
 382                         all_tags = 1;
 383                 else if (!strcmp(arg, "--more"))
 384                         extra = 1;
 385                 else if (!strcmp(arg, "--list"))
 386                         extra = -1;
 387                 else if (!strcmp(arg, "--no-name"))
 388                         no_name = 1;
 389                 else if (!strcmp(arg, "--sha1-name"))
 390                         sha1_name = 1;
 391                 else if (!strncmp(arg, "--more=", 7))
 392                         extra = atoi(arg + 7);
 393                 else if (!strcmp(arg, "--merge-base"))
 394                         merge_base = 1;
 395                 else if (!strcmp(arg, "--independent"))
 396                         independent = 1;
 397                 else
 398                         usage(show_branch_usage);
 399                 ac--; av++;
 400         }
 401         ac--; av++;
 402
 403         /* Only one of these is allowed */
 404         if (1 < independent + merge_base + (extra != 0))
 405                 usage(show_branch_usage);
 406
 407         if (all_heads + all_tags)
 408                 snarf_refs(all_heads, all_tags);
 409
 410         while (0 < ac) {
 411                 unsigned char revkey[20];
 412                 if (get_sha1(*av, revkey))
 413                         die("bad sha1 reference %s", *av);
 414                 append_ref(*av, revkey);
 415                 ac--; av++;
 416         }
 417
 418         /* If still no revs, then add heads */
 419         if (!ref_name_cnt)
 420                 snarf_refs(1, 0);
 421
 422         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 423                 unsigned char revkey[20];
 424                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 425
 426                 if (MAX_REVS <= num_rev)
 427                         die("cannot handle more than %d revs.", MAX_REVS);
 428                 if (get_sha1(ref_name[num_rev], revkey))
 429                         usage(show_branch_usage);
 430                 commit = lookup_commit_reference(revkey);
 431                 if (!commit)
 432                         die("cannot find commit %s (%s)",
 433                             ref_name[num_rev], revkey);
 434                 parse_commit(commit);
 435                 mark_seen(commit, &seen);
 436
 437                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 438                  * and so on.  REV_SHIFT bits from bit 0 are used for
 439                  * internal bookkeeping.
 440                  */
 441                 commit->object.flags |= flag;
 442                 if (commit->object.flags == flag)
 443                         insert_by_date(commit, &list);
 444                 rev[num_rev] = commit;
 445         }
 446         for (i = 0; i < num_rev; i++)
 447                 rev_mask[i] = rev[i]->object.flags;
 448
 449         if (0 <= extra)
 450                 join_revs(&list, &seen, num_rev, extra);
 451
 452         head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1);
 453         if (head_path_p) {
 454                 head_path_len = strlen(head_path_p);
 455                 memcpy(head_path, head_path_p, head_path_len + 1);
 456         }
 457         else {
 458                 head_path_len = 0;
 459                 head_path[0] = 0;
 460         }
 461
 462         if (merge_base)
 463                 return show_merge_base(seen, num_rev);
 464
 465         if (independent)
 466                 return show_independent(rev, num_rev, ref_name, rev_mask);
 467
 468         /* Show list; --more=-1 means list-only */
 469         if (1 < num_rev || extra < 0) {
 470                 for (i = 0; i < num_rev; i++) {
 471                         int j;
 472                         int is_head = rev_is_head(head_path,
 473                                                   head_path_len,
 474                                                   ref_name[i],
 475                                                   head_sha1,
 476                                                   rev[i]->object.sha1);
 477                         if (extra < 0)
 478                                 printf("%c [%s] ",
 479                                        is_head ? '*' : ' ', ref_name[i]);
 480                         else {
 481                                 for (j = 0; j < i; j++)
 482                                         putchar(' ');
 483                                 printf("%c [%s] ",
 484                                        is_head ? '*' : '!', ref_name[i]);
 485                         }
 486                         /* header lines never need name */
 487                         show_one_commit(rev[i], 1);
 488                 }
 489                 if (0 <= extra) {
 490                         for (i = 0; i < num_rev; i++)
 491                                 putchar('-');
 492                         putchar('\n');
 493                 }
 494         }
 495         if (extra < 0)
 496                 exit(0);
 497
 498         /* Sort topologically */
 499         sort_in_topological_order(&seen);
 500
 501         /* Give names to commits */
 502         if (!sha1_name && !no_name)
 503                 name_commits(seen, rev, ref_name, num_rev);
 504
 505         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 506         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 507         shown_merge_point = 0;
 508
 509         while (seen) {
 510                 struct commit *commit = pop_one_commit(&seen);
 511                 int this_flag = commit->object.flags;
 512                 int is_merge_point = (this_flag & all_revs) == all_revs;
 513
 514                 if (is_merge_point)
 515                         shown_merge_point = 1;
 516
 517                 if (1 < num_rev) {
 518                         for (i = 0; i < num_rev; i++)
 519                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
 520                                         ? '+' : ' ');
 521                         putchar(' ');
 522                 }
 523                 show_one_commit(commit, no_name);
 524                 if (shown_merge_point && is_merge_point)
 525                         if (--extra < 0)
 526                                 break;
 527         }
 528         return 0;
 529 }