commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "pkt-line.h"
   5 #include "utf8.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8
   9 int save_commit_buffer = 1;
  10
  11 const char *commit_type = "commit";
  12
  13 static struct commit *check_commit(struct object *obj,
  14                                    const unsigned char *sha1,
  15                                    int quiet)
  16 {
  17         if (obj->type != OBJ_COMMIT) {
  18                 if (!quiet)
  19                         error("Object %s is a %s, not a commit",
  20                               sha1_to_hex(sha1), typename(obj->type));
  21                 return NULL;
  22         }
  23         return (struct commit *) obj;
  24 }
  25
  26 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  27                                               int quiet)
  28 {
  29         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  30
  31         if (!obj)
  32                 return NULL;
  33         return check_commit(obj, sha1, quiet);
  34 }
  35
  36 struct commit *lookup_commit_reference(const unsigned char *sha1)
  37 {
  38         return lookup_commit_reference_gently(sha1, 0);
  39 }
  40
  41 struct commit *lookup_commit(const unsigned char *sha1)
  42 {
  43         struct object *obj = lookup_object(sha1);
  44         if (!obj)
  45                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  46         if (!obj->type)
  47                 obj->type = OBJ_COMMIT;
  48         return check_commit(obj, sha1, 0);
  49 }
  50
  51 static unsigned long parse_commit_date(const char *buf, const char *tail)
  52 {
  53         unsigned long date;
  54         const char *dateptr;
  55
  56         if (buf + 6 >= tail)
  57                 return 0;
  58         if (memcmp(buf, "author", 6))
  59                 return 0;
  60         while (buf < tail && *buf++ != '\n')
  61                 /* nada */;
  62         if (buf + 9 >= tail)
  63                 return 0;
  64         if (memcmp(buf, "committer", 9))
  65                 return 0;
  66         while (buf < tail && *buf++ != '>')
  67                 /* nada */;
  68         if (buf >= tail)
  69                 return 0;
  70         dateptr = buf;
  71         while (buf < tail && *buf++ != '\n')
  72                 /* nada */;
  73         if (buf >= tail)
  74                 return 0;
  75         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  76         date = strtoul(dateptr, NULL, 10);
  77         if (date == ULONG_MAX)
  78                 date = 0;
  79         return date;
  80 }
  81
  82 static struct commit_graft **commit_graft;
  83 static int commit_graft_alloc, commit_graft_nr;
  84
  85 static int commit_graft_pos(const unsigned char *sha1)
  86 {
  87         int lo, hi;
  88         lo = 0;
  89         hi = commit_graft_nr;
  90         while (lo < hi) {
  91                 int mi = (lo + hi) / 2;
  92                 struct commit_graft *graft = commit_graft[mi];
  93                 int cmp = hashcmp(sha1, graft->sha1);
  94                 if (!cmp)
  95                         return mi;
  96                 if (cmp < 0)
  97                         hi = mi;
  98                 else
  99                         lo = mi + 1;
 100         }
 101         return -lo - 1;
 102 }
 103
 104 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 105 {
 106         int pos = commit_graft_pos(graft->sha1);
 107
 108         if (0 <= pos) {
 109                 if (ignore_dups)
 110                         free(graft);
 111                 else {
 112                         free(commit_graft[pos]);
 113                         commit_graft[pos] = graft;
 114                 }
 115                 return 1;
 116         }
 117         pos = -pos - 1;
 118         if (commit_graft_alloc <= ++commit_graft_nr) {
 119                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 120                 commit_graft = xrealloc(commit_graft,
 121                                         sizeof(*commit_graft) *
 122                                         commit_graft_alloc);
 123         }
 124         if (pos < commit_graft_nr)
 125                 memmove(commit_graft + pos + 1,
 126                         commit_graft + pos,
 127                         (commit_graft_nr - pos - 1) *
 128                         sizeof(*commit_graft));
 129         commit_graft[pos] = graft;
 130         return 0;
 131 }
 132
 133 struct commit_graft *read_graft_line(char *buf, int len)
 134 {
 135         /* The format is just "Commit Parent1 Parent2 ...\n" */
 136         int i;
 137         struct commit_graft *graft = NULL;
 138
 139         if (buf[len-1] == '\n')
 140                 buf[--len] = 0;
 141         if (buf[0] == '#' || buf[0] == '\0')
 142                 return NULL;
 143         if ((len + 1) % 41) {
 144         bad_graft_data:
 145                 error("bad graft data: %s", buf);
 146                 free(graft);
 147                 return NULL;
 148         }
 149         i = (len + 1) / 41 - 1;
 150         graft = xmalloc(sizeof(*graft) + 20 * i);
 151         graft->nr_parent = i;
 152         if (get_sha1_hex(buf, graft->sha1))
 153                 goto bad_graft_data;
 154         for (i = 40; i < len; i += 41) {
 155                 if (buf[i] != ' ')
 156                         goto bad_graft_data;
 157                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 158                         goto bad_graft_data;
 159         }
 160         return graft;
 161 }
 162
 163 int read_graft_file(const char *graft_file)
 164 {
 165         FILE *fp = fopen(graft_file, "r");
 166         char buf[1024];
 167         if (!fp)
 168                 return -1;
 169         while (fgets(buf, sizeof(buf), fp)) {
 170                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 171                 int len = strlen(buf);
 172                 struct commit_graft *graft = read_graft_line(buf, len);
 173                 if (!graft)
 174                         continue;
 175                 if (register_commit_graft(graft, 1))
 176                         error("duplicate graft data: %s", buf);
 177         }
 178         fclose(fp);
 179         return 0;
 180 }
 181
 182 static void prepare_commit_graft(void)
 183 {
 184         static int commit_graft_prepared;
 185         char *graft_file;
 186
 187         if (commit_graft_prepared)
 188                 return;
 189         graft_file = get_graft_file();
 190         read_graft_file(graft_file);
 191         /* make sure shallows are read */
 192         is_repository_shallow();
 193         commit_graft_prepared = 1;
 194 }
 195
 196 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 197 {
 198         int pos;
 199         prepare_commit_graft();
 200         pos = commit_graft_pos(sha1);
 201         if (pos < 0)
 202                 return NULL;
 203         return commit_graft[pos];
 204 }
 205
 206 int write_shallow_commits(int fd, int use_pack_protocol)
 207 {
 208         int i, count = 0;
 209         for (i = 0; i < commit_graft_nr; i++)
 210                 if (commit_graft[i]->nr_parent < 0) {
 211                         const char *hex =
 212                                 sha1_to_hex(commit_graft[i]->sha1);
 213                         count++;
 214                         if (use_pack_protocol)
 215                                 packet_write(fd, "shallow %s", hex);
 216                         else {
 217                                 if (write_in_full(fd, hex,  40) != 40)
 218                                         break;
 219                                 if (write_in_full(fd, "\n", 1) != 1)
 220                                         break;
 221                         }
 222                 }
 223         return count;
 224 }
 225
 226 int unregister_shallow(const unsigned char *sha1)
 227 {
 228         int pos = commit_graft_pos(sha1);
 229         if (pos < 0)
 230                 return -1;
 231         if (pos + 1 < commit_graft_nr)
 232                 memcpy(commit_graft + pos, commit_graft + pos + 1,
 233                                 sizeof(struct commit_graft *)
 234                                 * (commit_graft_nr - pos - 1));
 235         commit_graft_nr--;
 236         return 0;
 237 }
 238
 239 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 240 {
 241         char *tail = buffer;
 242         char *bufptr = buffer;
 243         unsigned char parent[20];
 244         struct commit_list **pptr;
 245         struct commit_graft *graft;
 246         unsigned n_refs = 0;
 247
 248         if (item->object.parsed)
 249                 return 0;
 250         item->object.parsed = 1;
 251         tail += size;
 252         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 253                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 254         if (get_sha1_hex(bufptr + 5, parent) < 0)
 255                 return error("bad tree pointer in commit %s",
 256                              sha1_to_hex(item->object.sha1));
 257         item->tree = lookup_tree(parent);
 258         if (item->tree)
 259                 n_refs++;
 260         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 261         pptr = &item->parents;
 262
 263         graft = lookup_commit_graft(item->object.sha1);
 264         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 265                 struct commit *new_parent;
 266
 267                 if (tail <= bufptr + 48 ||
 268                     get_sha1_hex(bufptr + 7, parent) ||
 269                     bufptr[47] != '\n')
 270                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 271                 bufptr += 48;
 272                 if (graft)
 273                         continue;
 274                 new_parent = lookup_commit(parent);
 275                 if (new_parent) {
 276                         pptr = &commit_list_insert(new_parent, pptr)->next;
 277                         n_refs++;
 278                 }
 279         }
 280         if (graft) {
 281                 int i;
 282                 struct commit *new_parent;
 283                 for (i = 0; i < graft->nr_parent; i++) {
 284                         new_parent = lookup_commit(graft->parent[i]);
 285                         if (!new_parent)
 286                                 continue;
 287                         pptr = &commit_list_insert(new_parent, pptr)->next;
 288                         n_refs++;
 289                 }
 290         }
 291         item->date = parse_commit_date(bufptr, tail);
 292
 293         return 0;
 294 }
 295
 296 int parse_commit(struct commit *item)
 297 {
 298         enum object_type type;
 299         void *buffer;
 300         unsigned long size;
 301         int ret;
 302
 303         if (!item)
 304                 return -1;
 305         if (item->object.parsed)
 306                 return 0;
 307         buffer = read_sha1_file(item->object.sha1, &type, &size);
 308         if (!buffer)
 309                 return error("Could not read %s",
 310                              sha1_to_hex(item->object.sha1));
 311         if (type != OBJ_COMMIT) {
 312                 free(buffer);
 313                 return error("Object %s not a commit",
 314                              sha1_to_hex(item->object.sha1));
 315         }
 316         ret = parse_commit_buffer(item, buffer, size);
 317         if (save_commit_buffer && !ret) {
 318                 item->buffer = buffer;
 319                 return 0;
 320         }
 321         free(buffer);
 322         return ret;
 323 }
 324
 325 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 326 {
 327         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 328         new_list->item = item;
 329         new_list->next = *list_p;
 330         *list_p = new_list;
 331         return new_list;
 332 }
 333
 334 void free_commit_list(struct commit_list *list)
 335 {
 336         while (list) {
 337                 struct commit_list *temp = list;
 338                 list = temp->next;
 339                 free(temp);
 340         }
 341 }
 342
 343 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 344 {
 345         struct commit_list **pp = list;
 346         struct commit_list *p;
 347         while ((p = *pp) != NULL) {
 348                 if (p->item->date < item->date) {
 349                         break;
 350                 }
 351                 pp = &p->next;
 352         }
 353         return commit_list_insert(item, pp);
 354 }
 355
 356
 357 void sort_by_date(struct commit_list **list)
 358 {
 359         struct commit_list *ret = NULL;
 360         while (*list) {
 361                 insert_by_date((*list)->item, &ret);
 362                 *list = (*list)->next;
 363         }
 364         *list = ret;
 365 }
 366
 367 struct commit *pop_most_recent_commit(struct commit_list **list,
 368                                       unsigned int mark)
 369 {
 370         struct commit *ret = (*list)->item;
 371         struct commit_list *parents = ret->parents;
 372         struct commit_list *old = *list;
 373
 374         *list = (*list)->next;
 375         free(old);
 376
 377         while (parents) {
 378                 struct commit *commit = parents->item;
 379                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 380                         commit->object.flags |= mark;
 381                         insert_by_date(commit, list);
 382                 }
 383                 parents = parents->next;
 384         }
 385         return ret;
 386 }
 387
 388 void clear_commit_marks(struct commit *commit, unsigned int mark)
 389 {
 390         while (commit) {
 391                 struct commit_list *parents;
 392
 393                 if (!(mark & commit->object.flags))
 394                         return;
 395
 396                 commit->object.flags &= ~mark;
 397
 398                 parents = commit->parents;
 399                 if (!parents)
 400                         return;
 401
 402                 while ((parents = parents->next))
 403                         clear_commit_marks(parents->item, mark);
 404
 405                 commit = commit->parents->item;
 406         }
 407 }
 408
 409 struct commit *pop_commit(struct commit_list **stack)
 410 {
 411         struct commit_list *top = *stack;
 412         struct commit *item = top ? top->item : NULL;
 413
 414         if (top) {
 415                 *stack = top->next;
 416                 free(top);
 417         }
 418         return item;
 419 }
 420
 421 /*
 422  * Performs an in-place topological sort on the list supplied.
 423  */
 424 void sort_in_topological_order(struct commit_list ** list, int lifo)
 425 {
 426         struct commit_list *next, *orig = *list;
 427         struct commit_list *work, **insert;
 428         struct commit_list **pptr;
 429
 430         if (!orig)
 431                 return;
 432         *list = NULL;
 433
 434         /* Mark them and clear the indegree */
 435         for (next = orig; next; next = next->next) {
 436                 struct commit *commit = next->item;
 437                 commit->object.flags |= TOPOSORT;
 438                 commit->indegree = 0;
 439         }
 440
 441         /* update the indegree */
 442         for (next = orig; next; next = next->next) {
 443                 struct commit_list * parents = next->item->parents;
 444                 while (parents) {
 445                         struct commit *parent = parents->item;
 446
 447                         if (parent->object.flags & TOPOSORT)
 448                                 parent->indegree++;
 449                         parents = parents->next;
 450                 }
 451         }
 452
 453         /*
 454          * find the tips
 455          *
 456          * tips are nodes not reachable from any other node in the list
 457          *
 458          * the tips serve as a starting set for the work queue.
 459          */
 460         work = NULL;
 461         insert = &work;
 462         for (next = orig; next; next = next->next) {
 463                 struct commit *commit = next->item;
 464
 465                 if (!commit->indegree)
 466                         insert = &commit_list_insert(commit, insert)->next;
 467         }
 468
 469         /* process the list in topological order */
 470         if (!lifo)
 471                 sort_by_date(&work);
 472
 473         pptr = list;
 474         *list = NULL;
 475         while (work) {
 476                 struct commit *commit;
 477                 struct commit_list *parents, *work_item;
 478
 479                 work_item = work;
 480                 work = work_item->next;
 481                 work_item->next = NULL;
 482
 483                 commit = work_item->item;
 484                 for (parents = commit->parents; parents ; parents = parents->next) {
 485                         struct commit *parent=parents->item;
 486
 487                         if (!(parent->object.flags & TOPOSORT))
 488                                 continue;
 489
 490                         /*
 491                          * parents are only enqueued for emission
 492                          * when all their children have been emitted thereby
 493                          * guaranteeing topological order.
 494                          */
 495                         if (!--parent->indegree) {
 496                                 if (!lifo)
 497                                         insert_by_date(parent, &work);
 498                                 else
 499                                         commit_list_insert(parent, &work);
 500                         }
 501                 }
 502                 /*
 503                  * work_item is a commit all of whose children
 504                  * have already been emitted. we can emit it now.
 505                  */
 506                 commit->object.flags &= ~TOPOSORT;
 507                 *pptr = work_item;
 508                 pptr = &work_item->next;
 509         }
 510 }
 511
 512 /* merge-base stuff */
 513
 514 /* bits #0..15 in revision.h */
 515 #define PARENT1         (1u<<16)
 516 #define PARENT2         (1u<<17)
 517 #define STALE           (1u<<18)
 518 #define RESULT          (1u<<19)
 519
 520 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 521
 522 static struct commit *interesting(struct commit_list *list)
 523 {
 524         while (list) {
 525                 struct commit *commit = list->item;
 526                 list = list->next;
 527                 if (commit->object.flags & STALE)
 528                         continue;
 529                 return commit;
 530         }
 531         return NULL;
 532 }
 533
 534 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 535 {
 536         struct commit_list *list = NULL;
 537         struct commit_list *result = NULL;
 538
 539         if (one == two)
 540                 /* We do not mark this even with RESULT so we do not
 541                  * have to clean it up.
 542                  */
 543                 return commit_list_insert(one, &result);
 544
 545         if (parse_commit(one))
 546                 return NULL;
 547         if (parse_commit(two))
 548                 return NULL;
 549
 550         one->object.flags |= PARENT1;
 551         two->object.flags |= PARENT2;
 552         insert_by_date(one, &list);
 553         insert_by_date(two, &list);
 554
 555         while (interesting(list)) {
 556                 struct commit *commit;
 557                 struct commit_list *parents;
 558                 struct commit_list *n;
 559                 int flags;
 560
 561                 commit = list->item;
 562                 n = list->next;
 563                 free(list);
 564                 list = n;
 565
 566                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 567                 if (flags == (PARENT1 | PARENT2)) {
 568                         if (!(commit->object.flags & RESULT)) {
 569                                 commit->object.flags |= RESULT;
 570                                 insert_by_date(commit, &result);
 571                         }
 572                         /* Mark parents of a found merge stale */
 573                         flags |= STALE;
 574                 }
 575                 parents = commit->parents;
 576                 while (parents) {
 577                         struct commit *p = parents->item;
 578                         parents = parents->next;
 579                         if ((p->object.flags & flags) == flags)
 580                                 continue;
 581                         if (parse_commit(p))
 582                                 return NULL;
 583                         p->object.flags |= flags;
 584                         insert_by_date(p, &list);
 585                 }
 586         }
 587
 588         /* Clean up the result to remove stale ones */
 589         free_commit_list(list);
 590         list = result; result = NULL;
 591         while (list) {
 592                 struct commit_list *n = list->next;
 593                 if (!(list->item->object.flags & STALE))
 594                         insert_by_date(list->item, &result);
 595                 free(list);
 596                 list = n;
 597         }
 598         return result;
 599 }
 600
 601 struct commit_list *get_merge_bases(struct commit *one,
 602                                         struct commit *two, int cleanup)
 603 {
 604         struct commit_list *list;
 605         struct commit **rslt;
 606         struct commit_list *result;
 607         int cnt, i, j;
 608
 609         result = merge_bases(one, two);
 610         if (one == two)
 611                 return result;
 612         if (!result || !result->next) {
 613                 if (cleanup) {
 614                         clear_commit_marks(one, all_flags);
 615                         clear_commit_marks(two, all_flags);
 616                 }
 617                 return result;
 618         }
 619
 620         /* There are more than one */
 621         cnt = 0;
 622         list = result;
 623         while (list) {
 624                 list = list->next;
 625                 cnt++;
 626         }
 627         rslt = xcalloc(cnt, sizeof(*rslt));
 628         for (list = result, i = 0; list; list = list->next)
 629                 rslt[i++] = list->item;
 630         free_commit_list(result);
 631
 632         clear_commit_marks(one, all_flags);
 633         clear_commit_marks(two, all_flags);
 634         for (i = 0; i < cnt - 1; i++) {
 635                 for (j = i+1; j < cnt; j++) {
 636                         if (!rslt[i] || !rslt[j])
 637                                 continue;
 638                         result = merge_bases(rslt[i], rslt[j]);
 639                         clear_commit_marks(rslt[i], all_flags);
 640                         clear_commit_marks(rslt[j], all_flags);
 641                         for (list = result; list; list = list->next) {
 642                                 if (rslt[i] == list->item)
 643                                         rslt[i] = NULL;
 644                                 if (rslt[j] == list->item)
 645                                         rslt[j] = NULL;
 646                         }
 647                 }
 648         }
 649
 650         /* Surviving ones in rslt[] are the independent results */
 651         result = NULL;
 652         for (i = 0; i < cnt; i++) {
 653                 if (rslt[i])
 654                         insert_by_date(rslt[i], &result);
 655         }
 656         free(rslt);
 657         return result;
 658 }
 659
 660 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 661 {
 662         struct commit_list *bases, *b;
 663         int ret = 0;
 664
 665         if (num == 1)
 666                 bases = get_merge_bases(commit, *reference, 1);
 667         else
 668                 die("not yet");
 669         for (b = bases; b; b = b->next) {
 670                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 671                         ret = 1;
 672                         break;
 673                 }
 674         }
 675
 676         free_commit_list(bases);
 677         return ret;
 678 }