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];
 137                                 parents = parents->next;
 138                                 nth++;
 139                                 if (p->object.util)
 140                                         continue;
 141                                 switch (n->generation) {
 142                                 case 0:
 143                                         sprintf(newname, "%s^%d",
 144                                                 n->head_name, nth);
 145                                         break;
 146                                 case 1:
 147                                         sprintf(newname, "%s^^%d",
 148                                                 n->head_name, nth);
 149                                         break;
 150                                 default:
 151                                         sprintf(newname, "%s~%d^%d",
 152                                                 n->head_name, n->generation,
 153                                                 nth);
 154                                 }
 155                                 name_commit(p, strdup(newname), 0);
 156                                 i++;
 157                                 name_first_parent_chain(p);
 158                         }
 159                 }
 160         } while (i);
 161 }
 162
 163 static int mark_seen(struct commit *commit, struct commit_list **seen_p)
 164 {
 165         if (!commit->object.flags) {
 166                 insert_by_date(commit, seen_p);
 167                 return 1;
 168         }
 169         return 0;
 170 }
 171
 172 static void join_revs(struct commit_list **list_p,
 173                       struct commit_list **seen_p,
 174                       int num_rev, int extra)
 175 {
 176         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 177         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 178
 179         while (*list_p) {
 180                 struct commit_list *parents;
 181                 struct commit *commit = pop_one_commit(list_p);
 182                 int flags = commit->object.flags & all_mask;
 183                 int still_interesting = !!interesting(*list_p);
 184
 185                 if (!still_interesting && extra < 0)
 186                         break;
 187
 188                 mark_seen(commit, seen_p);
 189                 if ((flags & all_revs) == all_revs)
 190                         flags |= UNINTERESTING;
 191                 parents = commit->parents;
 192
 193                 while (parents) {
 194                         struct commit *p = parents->item;
 195                         int this_flag = p->object.flags;
 196                         parents = parents->next;
 197                         if ((this_flag & flags) == flags)
 198                                 continue;
 199                         parse_commit(p);
 200                         if (mark_seen(p, seen_p) && !still_interesting)
 201                                 extra--;
 202                         p->object.flags |= flags;
 203                         insert_by_date(p, list_p);
 204                 }
 205         }
 206 }
 207
 208 static void show_one_commit(struct commit *commit)
 209 {
 210         char pretty[128], *cp;
 211         struct commit_name *name = commit->object.util;
 212         if (commit->object.parsed)
 213                 pretty_print_commit(CMIT_FMT_ONELINE, commit->buffer, ~0,
 214                                     pretty, sizeof(pretty));
 215         else
 216                 strcpy(pretty, "(unavailable)");
 217         if (!strncmp(pretty, "[PATCH] ", 8))
 218                 cp = pretty + 8;
 219         else
 220                 cp = pretty;
 221         if (name && name->head_name) {
 222                 printf("[%s", name->head_name);
 223                 if (name->generation)
 224                         printf("~%d", name->generation);
 225                 printf("] ");
 226         }
 227         puts(cp);
 228 }
 229
 230 static char *ref_name[MAX_REVS + 1];
 231 static int ref_name_cnt;
 232
 233 static int compare_ref_name(const void *a_, const void *b_)
 234 {
 235         const char * const*a = a_, * const*b = b_;
 236         return strcmp(*a, *b);
 237 }
 238
 239 static void sort_ref_range(int bottom, int top)
 240 {
 241         qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
 242               compare_ref_name);
 243 }
 244
 245 static int append_ref(const char *refname, const unsigned char *sha1)
 246 {
 247         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 248         if (!commit)
 249                 return 0;
 250         if (MAX_REVS < ref_name_cnt) {
 251                 fprintf(stderr, "warning: ignoring %s; "
 252                         "cannot handle more than %d refs",
 253                         refname, MAX_REVS);
 254                 return 0;
 255         }
 256         ref_name[ref_name_cnt++] = strdup(refname);
 257         ref_name[ref_name_cnt] = NULL;
 258         return 0;
 259 }
 260
 261 static int append_head_ref(const char *refname, const unsigned char *sha1)
 262 {
 263         if (strncmp(refname, "refs/heads/", 11))
 264                 return 0;
 265         return append_ref(refname + 11, sha1);
 266 }
 267
 268 static int append_tag_ref(const char *refname, const unsigned char *sha1)
 269 {
 270         if (strncmp(refname, "refs/tags/", 10))
 271                 return 0;
 272         return append_ref(refname + 5, sha1);
 273 }
 274
 275 static void snarf_refs(int head, int tag)
 276 {
 277         if (head) {
 278                 int orig_cnt = ref_name_cnt;
 279                 for_each_ref(append_head_ref);
 280                 sort_ref_range(orig_cnt, ref_name_cnt);
 281         }
 282         if (tag) {
 283                 int orig_cnt = ref_name_cnt;
 284                 for_each_ref(append_tag_ref);
 285                 sort_ref_range(orig_cnt, ref_name_cnt);
 286         }
 287 }
 288
 289 static int rev_is_head(char *head_path, int headlen,
 290                        char *name,
 291                        unsigned char *head_sha1, unsigned char *sha1)
 292 {
 293         int namelen;
 294         if ((!head_path[0]) || memcmp(head_sha1, sha1, 20))
 295                 return 0;
 296         namelen = strlen(name);
 297         if ((headlen < namelen) ||
 298             memcmp(head_path + headlen - namelen, name, namelen))
 299                 return 0;
 300         if (headlen == namelen ||
 301             head_path[headlen - namelen - 1] == '/')
 302                 return 1;
 303         return 0;
 304 }
 305
 306 static int show_merge_base(struct commit_list *seen, int num_rev)
 307 {
 308         int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 309         int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 310         int exit_status = 1;
 311
 312         while (seen) {
 313                 struct commit *commit = pop_one_commit(&seen);
 314                 int flags = commit->object.flags & all_mask;
 315                 if (!(flags & UNINTERESTING) &&
 316                     ((flags & all_revs) == all_revs)) {
 317                         puts(sha1_to_hex(commit->object.sha1));
 318                         exit_status = 0;
 319                         commit->object.flags |= UNINTERESTING;
 320                 }
 321         }
 322         return exit_status;
 323 }
 324
 325 static int show_independent(struct commit **rev,
 326                             int num_rev,
 327                             char **ref_name,
 328                             unsigned int *rev_mask)
 329 {
 330         int i;
 331
 332         for (i = 0; i < num_rev; i++) {
 333                 struct commit *commit = rev[i];
 334                 unsigned int flag = rev_mask[i];
 335
 336                 if (commit->object.flags == flag)
 337                         puts(sha1_to_hex(commit->object.sha1));
 338                 commit->object.flags |= UNINTERESTING;
 339         }
 340         return 0;
 341 }
 342
 343 int main(int ac, char **av)
 344 {
 345         struct commit *rev[MAX_REVS], *commit;
 346         struct commit_list *list = NULL, *seen = NULL;
 347         unsigned int rev_mask[MAX_REVS];
 348         int num_rev, i, extra = 0;
 349         int all_heads = 0, all_tags = 0;
 350         int all_mask, all_revs, shown_merge_point;
 351         char head_path[128];
 352         const char *head_path_p;
 353         int head_path_len;
 354         unsigned char head_sha1[20];
 355         int merge_base = 0;
 356         int independent = 0;
 357         char **label;
 358
 359         setup_git_directory();
 360
 361         while (1 < ac && av[1][0] == '-') {
 362                 char *arg = av[1];
 363                 if (!strcmp(arg, "--all"))
 364                         all_heads = all_tags = 1;
 365                 else if (!strcmp(arg, "--heads"))
 366                         all_heads = 1;
 367                 else if (!strcmp(arg, "--tags"))
 368                         all_tags = 1;
 369                 else if (!strcmp(arg, "--more"))
 370                         extra = 1;
 371                 else if (!strcmp(arg, "--list"))
 372                         extra = -1;
 373                 else if (!strncmp(arg, "--more=", 7))
 374                         extra = atoi(arg + 7);
 375                 else if (!strcmp(arg, "--merge-base"))
 376                         merge_base = 1;
 377                 else if (!strcmp(arg, "--independent"))
 378                         independent = 1;
 379                 else
 380                         usage(show_branch_usage);
 381                 ac--; av++;
 382         }
 383         ac--; av++;
 384
 385         /* Only one of these is allowed */
 386         if (1 < independent + merge_base + (extra != 0))
 387                 usage(show_branch_usage);
 388
 389         if (all_heads + all_tags)
 390                 snarf_refs(all_heads, all_tags);
 391
 392         while (0 < ac) {
 393                 unsigned char revkey[20];
 394                 if (get_sha1(*av, revkey))
 395                         die("bad sha1 reference %s", *av);
 396                 append_ref(*av, revkey);
 397                 ac--; av++;
 398         }
 399
 400         /* If still no revs, then add heads */
 401         if (!ref_name_cnt)
 402                 snarf_refs(1, 0);
 403
 404         for (num_rev = 0; ref_name[num_rev]; num_rev++) {
 405                 unsigned char revkey[20];
 406                 unsigned int flag = 1u << (num_rev + REV_SHIFT);
 407
 408                 if (MAX_REVS <= num_rev)
 409                         die("cannot handle more than %d revs.", MAX_REVS);
 410                 if (get_sha1(ref_name[num_rev], revkey))
 411                         usage(show_branch_usage);
 412                 commit = lookup_commit_reference(revkey);
 413                 if (!commit)
 414                         die("cannot find commit %s (%s)",
 415                             ref_name[num_rev], revkey);
 416                 parse_commit(commit);
 417                 mark_seen(commit, &seen);
 418
 419                 /* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
 420                  * and so on.  REV_SHIFT bits from bit 0 are used for
 421                  * internal bookkeeping.
 422                  */
 423                 commit->object.flags |= flag;
 424                 if (commit->object.flags == flag)
 425                         insert_by_date(commit, &list);
 426                 rev[num_rev] = commit;
 427         }
 428         for (i = 0; i < num_rev; i++)
 429                 rev_mask[i] = rev[i]->object.flags;
 430
 431         if (0 <= extra)
 432                 join_revs(&list, &seen, num_rev, extra);
 433
 434         head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1);
 435         if (head_path_p) {
 436                 head_path_len = strlen(head_path_p);
 437                 memcpy(head_path, head_path_p, head_path_len + 1);
 438         }
 439         else {
 440                 head_path_len = 0;
 441                 head_path[0] = 0;
 442         }
 443
 444         if (merge_base)
 445                 return show_merge_base(seen, num_rev);
 446
 447         if (independent)
 448                 return show_independent(rev, num_rev, ref_name, rev_mask);
 449
 450         /* Show list; --more=-1 means list-only */
 451         if (1 < num_rev || extra < 0) {
 452                 for (i = 0; i < num_rev; i++) {
 453                         int j;
 454                         int is_head = rev_is_head(head_path,
 455                                                   head_path_len,
 456                                                   ref_name[i],
 457                                                   head_sha1,
 458                                                   rev[i]->object.sha1);
 459                         if (extra < 0)
 460                                 printf("%c [%s] ",
 461                                        is_head ? '*' : ' ', ref_name[i]);
 462                         else {
 463                                 for (j = 0; j < i; j++)
 464                                         putchar(' ');
 465                                 printf("%c [%s] ",
 466                                        is_head ? '*' : '!', ref_name[i]);
 467                         }
 468                         show_one_commit(rev[i]);
 469                 }
 470                 if (0 <= extra) {
 471                         for (i = 0; i < num_rev; i++)
 472                                 putchar('-');
 473                         putchar('\n');
 474                 }
 475         }
 476         if (extra < 0)
 477                 exit(0);
 478
 479         /* Sort topologically */
 480         sort_in_topological_order(&seen);
 481
 482         /* Give names to commits */
 483         name_commits(seen, rev, ref_name, num_rev);
 484
 485         all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
 486         all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 487         shown_merge_point = 0;
 488
 489         while (seen) {
 490                 struct commit *commit = pop_one_commit(&seen);
 491                 int this_flag = commit->object.flags;
 492                 int is_merge_point = (this_flag & all_revs) == all_revs;
 493                 static char *obvious[] = { "" };
 494
 495                 if (is_merge_point)
 496                         shown_merge_point = 1;
 497
 498                 if (1 < num_rev) {
 499                         for (i = 0; i < num_rev; i++)
 500                                 putchar((this_flag & (1u << (i + REV_SHIFT)))
 501                                         ? '+' : ' ');
 502                         putchar(' ');
 503                 }
 504                 show_one_commit(commit);
 505                 if (num_rev == 1)
 506                         label = obvious;
 507                 if (shown_merge_point && is_merge_point)
 508                         if (--extra < 0)
 509                                 break;
 510         }
 511         return 0;
 512 }