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 static 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         if (track_object_refs) {
 294                 unsigned i = 0;
 295                 struct commit_list *p;
 296                 struct object_refs *refs = alloc_object_refs(n_refs);
 297                 if (item->tree)
 298                         refs->ref[i++] = &item->tree->object;
 299                 for (p = item->parents; p; p = p->next)
 300                         refs->ref[i++] = &p->item->object;
 301                 set_object_refs(&item->object, refs);
 302         }
 303
 304         return 0;
 305 }
 306
 307 int parse_commit(struct commit *item)
 308 {
 309         enum object_type type;
 310         void *buffer;
 311         unsigned long size;
 312         int ret;
 313
 314         if (!item)
 315                 return -1;
 316         if (item->object.parsed)
 317                 return 0;
 318         buffer = read_sha1_file(item->object.sha1, &type, &size);
 319         if (!buffer)
 320                 return error("Could not read %s",
 321                              sha1_to_hex(item->object.sha1));
 322         if (type != OBJ_COMMIT) {
 323                 free(buffer);
 324                 return error("Object %s not a commit",
 325                              sha1_to_hex(item->object.sha1));
 326         }
 327         ret = parse_commit_buffer(item, buffer, size);
 328         if (save_commit_buffer && !ret) {
 329                 item->buffer = buffer;
 330                 return 0;
 331         }
 332         free(buffer);
 333         return ret;
 334 }
 335
 336 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 337 {
 338         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 339         new_list->item = item;
 340         new_list->next = *list_p;
 341         *list_p = new_list;
 342         return new_list;
 343 }
 344
 345 void free_commit_list(struct commit_list *list)
 346 {
 347         while (list) {
 348                 struct commit_list *temp = list;
 349                 list = temp->next;
 350                 free(temp);
 351         }
 352 }
 353
 354 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 355 {
 356         struct commit_list **pp = list;
 357         struct commit_list *p;
 358         while ((p = *pp) != NULL) {
 359                 if (p->item->date < item->date) {
 360                         break;
 361                 }
 362                 pp = &p->next;
 363         }
 364         return commit_list_insert(item, pp);
 365 }
 366
 367
 368 void sort_by_date(struct commit_list **list)
 369 {
 370         struct commit_list *ret = NULL;
 371         while (*list) {
 372                 insert_by_date((*list)->item, &ret);
 373                 *list = (*list)->next;
 374         }
 375         *list = ret;
 376 }
 377
 378 struct commit *pop_most_recent_commit(struct commit_list **list,
 379                                       unsigned int mark)
 380 {
 381         struct commit *ret = (*list)->item;
 382         struct commit_list *parents = ret->parents;
 383         struct commit_list *old = *list;
 384
 385         *list = (*list)->next;
 386         free(old);
 387
 388         while (parents) {
 389                 struct commit *commit = parents->item;
 390                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 391                         commit->object.flags |= mark;
 392                         insert_by_date(commit, list);
 393                 }
 394                 parents = parents->next;
 395         }
 396         return ret;
 397 }
 398
 399 void clear_commit_marks(struct commit *commit, unsigned int mark)
 400 {
 401         while (commit) {
 402                 struct commit_list *parents;
 403
 404                 if (!(mark & commit->object.flags))
 405                         return;
 406
 407                 commit->object.flags &= ~mark;
 408
 409                 parents = commit->parents;
 410                 if (!parents)
 411                         return;
 412
 413                 while ((parents = parents->next))
 414                         clear_commit_marks(parents->item, mark);
 415
 416                 commit = commit->parents->item;
 417         }
 418 }
 419
 420 struct commit *pop_commit(struct commit_list **stack)
 421 {
 422         struct commit_list *top = *stack;
 423         struct commit *item = top ? top->item : NULL;
 424
 425         if (top) {
 426                 *stack = top->next;
 427                 free(top);
 428         }
 429         return item;
 430 }
 431
 432 /*
 433  * Performs an in-place topological sort on the list supplied.
 434  */
 435 void sort_in_topological_order(struct commit_list ** list, int lifo)
 436 {
 437         struct commit_list *next, *orig = *list;
 438         struct commit_list *work, **insert;
 439         struct commit_list **pptr;
 440
 441         if (!orig)
 442                 return;
 443         *list = NULL;
 444
 445         /* Mark them and clear the indegree */
 446         for (next = orig; next; next = next->next) {
 447                 struct commit *commit = next->item;
 448                 commit->object.flags |= TOPOSORT;
 449                 commit->indegree = 0;
 450         }
 451
 452         /* update the indegree */
 453         for (next = orig; next; next = next->next) {
 454                 struct commit_list * parents = next->item->parents;
 455                 while (parents) {
 456                         struct commit *parent = parents->item;
 457
 458                         if (parent->object.flags & TOPOSORT)
 459                                 parent->indegree++;
 460                         parents = parents->next;
 461                 }
 462         }
 463
 464         /*
 465          * find the tips
 466          *
 467          * tips are nodes not reachable from any other node in the list
 468          *
 469          * the tips serve as a starting set for the work queue.
 470          */
 471         work = NULL;
 472         insert = &work;
 473         for (next = orig; next; next = next->next) {
 474                 struct commit *commit = next->item;
 475
 476                 if (!commit->indegree)
 477                         insert = &commit_list_insert(commit, insert)->next;
 478         }
 479
 480         /* process the list in topological order */
 481         if (!lifo)
 482                 sort_by_date(&work);
 483
 484         pptr = list;
 485         *list = NULL;
 486         while (work) {
 487                 struct commit *commit;
 488                 struct commit_list *parents, *work_item;
 489
 490                 work_item = work;
 491                 work = work_item->next;
 492                 work_item->next = NULL;
 493
 494                 commit = work_item->item;
 495                 for (parents = commit->parents; parents ; parents = parents->next) {
 496                         struct commit *parent=parents->item;
 497
 498                         if (!(parent->object.flags & TOPOSORT))
 499                                 continue;
 500
 501                         /*
 502                          * parents are only enqueued for emission
 503                          * when all their children have been emitted thereby
 504                          * guaranteeing topological order.
 505                          */
 506                         if (!--parent->indegree) {
 507                                 if (!lifo)
 508                                         insert_by_date(parent, &work);
 509                                 else
 510                                         commit_list_insert(parent, &work);
 511                         }
 512                 }
 513                 /*
 514                  * work_item is a commit all of whose children
 515                  * have already been emitted. we can emit it now.
 516                  */
 517                 commit->object.flags &= ~TOPOSORT;
 518                 *pptr = work_item;
 519                 pptr = &work_item->next;
 520         }
 521 }
 522
 523 /* merge-base stuff */
 524
 525 /* bits #0..15 in revision.h */
 526 #define PARENT1         (1u<<16)
 527 #define PARENT2         (1u<<17)
 528 #define STALE           (1u<<18)
 529 #define RESULT          (1u<<19)
 530
 531 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 532
 533 static struct commit *interesting(struct commit_list *list)
 534 {
 535         while (list) {
 536                 struct commit *commit = list->item;
 537                 list = list->next;
 538                 if (commit->object.flags & STALE)
 539                         continue;
 540                 return commit;
 541         }
 542         return NULL;
 543 }
 544
 545 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 546 {
 547         struct commit_list *list = NULL;
 548         struct commit_list *result = NULL;
 549
 550         if (one == two)
 551                 /* We do not mark this even with RESULT so we do not
 552                  * have to clean it up.
 553                  */
 554                 return commit_list_insert(one, &result);
 555
 556         if (parse_commit(one))
 557                 return NULL;
 558         if (parse_commit(two))
 559                 return NULL;
 560
 561         one->object.flags |= PARENT1;
 562         two->object.flags |= PARENT2;
 563         insert_by_date(one, &list);
 564         insert_by_date(two, &list);
 565
 566         while (interesting(list)) {
 567                 struct commit *commit;
 568                 struct commit_list *parents;
 569                 struct commit_list *n;
 570                 int flags;
 571
 572                 commit = list->item;
 573                 n = list->next;
 574                 free(list);
 575                 list = n;
 576
 577                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 578                 if (flags == (PARENT1 | PARENT2)) {
 579                         if (!(commit->object.flags & RESULT)) {
 580                                 commit->object.flags |= RESULT;
 581                                 insert_by_date(commit, &result);
 582                         }
 583                         /* Mark parents of a found merge stale */
 584                         flags |= STALE;
 585                 }
 586                 parents = commit->parents;
 587                 while (parents) {
 588                         struct commit *p = parents->item;
 589                         parents = parents->next;
 590                         if ((p->object.flags & flags) == flags)
 591                                 continue;
 592                         if (parse_commit(p))
 593                                 return NULL;
 594                         p->object.flags |= flags;
 595                         insert_by_date(p, &list);
 596                 }
 597         }
 598
 599         /* Clean up the result to remove stale ones */
 600         free_commit_list(list);
 601         list = result; result = NULL;
 602         while (list) {
 603                 struct commit_list *n = list->next;
 604                 if (!(list->item->object.flags & STALE))
 605                         insert_by_date(list->item, &result);
 606                 free(list);
 607                 list = n;
 608         }
 609         return result;
 610 }
 611
 612 struct commit_list *get_merge_bases(struct commit *one,
 613                                         struct commit *two, int cleanup)
 614 {
 615         struct commit_list *list;
 616         struct commit **rslt;
 617         struct commit_list *result;
 618         int cnt, i, j;
 619
 620         result = merge_bases(one, two);
 621         if (one == two)
 622                 return result;
 623         if (!result || !result->next) {
 624                 if (cleanup) {
 625                         clear_commit_marks(one, all_flags);
 626                         clear_commit_marks(two, all_flags);
 627                 }
 628                 return result;
 629         }
 630
 631         /* There are more than one */
 632         cnt = 0;
 633         list = result;
 634         while (list) {
 635                 list = list->next;
 636                 cnt++;
 637         }
 638         rslt = xcalloc(cnt, sizeof(*rslt));
 639         for (list = result, i = 0; list; list = list->next)
 640                 rslt[i++] = list->item;
 641         free_commit_list(result);
 642
 643         clear_commit_marks(one, all_flags);
 644         clear_commit_marks(two, all_flags);
 645         for (i = 0; i < cnt - 1; i++) {
 646                 for (j = i+1; j < cnt; j++) {
 647                         if (!rslt[i] || !rslt[j])
 648                                 continue;
 649                         result = merge_bases(rslt[i], rslt[j]);
 650                         clear_commit_marks(rslt[i], all_flags);
 651                         clear_commit_marks(rslt[j], all_flags);
 652                         for (list = result; list; list = list->next) {
 653                                 if (rslt[i] == list->item)
 654                                         rslt[i] = NULL;
 655                                 if (rslt[j] == list->item)
 656                                         rslt[j] = NULL;
 657                         }
 658                 }
 659         }
 660
 661         /* Surviving ones in rslt[] are the independent results */
 662         result = NULL;
 663         for (i = 0; i < cnt; i++) {
 664                 if (rslt[i])
 665                         insert_by_date(rslt[i], &result);
 666         }
 667         free(rslt);
 668         return result;
 669 }
 670
 671 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 672 {
 673         struct commit_list *bases, *b;
 674         int ret = 0;
 675
 676         if (num == 1)
 677                 bases = get_merge_bases(commit, *reference, 1);
 678         else
 679                 die("not yet");
 680         for (b = bases; b; b = b->next) {
 681                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 682                         ret = 1;
 683                         break;
 684                 }
 685         }
 686
 687         free_commit_list(bases);
 688         return ret;
 689 }