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 struct sort_node
  12 {
  13         /*
  14          * the number of children of the associated commit
  15          * that also occur in the list being sorted.
  16          */
  17         unsigned int indegree;
  18
  19         /*
  20          * reference to original list item that we will re-use
  21          * on output.
  22          */
  23         struct commit_list * list_item;
  24
  25 };
  26
  27 const char *commit_type = "commit";
  28
  29 static struct commit *check_commit(struct object *obj,
  30                                    const unsigned char *sha1,
  31                                    int quiet)
  32 {
  33         if (obj->type != OBJ_COMMIT) {
  34                 if (!quiet)
  35                         error("Object %s is a %s, not a commit",
  36                               sha1_to_hex(sha1), typename(obj->type));
  37                 return NULL;
  38         }
  39         return (struct commit *) obj;
  40 }
  41
  42 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  43                                               int quiet)
  44 {
  45         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  46
  47         if (!obj)
  48                 return NULL;
  49         return check_commit(obj, sha1, quiet);
  50 }
  51
  52 struct commit *lookup_commit_reference(const unsigned char *sha1)
  53 {
  54         return lookup_commit_reference_gently(sha1, 0);
  55 }
  56
  57 struct commit *lookup_commit(const unsigned char *sha1)
  58 {
  59         struct object *obj = lookup_object(sha1);
  60         if (!obj)
  61                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  62         if (!obj->type)
  63                 obj->type = OBJ_COMMIT;
  64         return check_commit(obj, sha1, 0);
  65 }
  66
  67 static unsigned long parse_commit_date(const char *buf)
  68 {
  69         unsigned long date;
  70
  71         if (memcmp(buf, "author", 6))
  72                 return 0;
  73         while (*buf++ != '\n')
  74                 /* nada */;
  75         if (memcmp(buf, "committer", 9))
  76                 return 0;
  77         while (*buf++ != '>')
  78                 /* nada */;
  79         date = strtoul(buf, NULL, 10);
  80         if (date == ULONG_MAX)
  81                 date = 0;
  82         return date;
  83 }
  84
  85 static struct commit_graft **commit_graft;
  86 static int commit_graft_alloc, commit_graft_nr;
  87
  88 static int commit_graft_pos(const unsigned char *sha1)
  89 {
  90         int lo, hi;
  91         lo = 0;
  92         hi = commit_graft_nr;
  93         while (lo < hi) {
  94                 int mi = (lo + hi) / 2;
  95                 struct commit_graft *graft = commit_graft[mi];
  96                 int cmp = hashcmp(sha1, graft->sha1);
  97                 if (!cmp)
  98                         return mi;
  99                 if (cmp < 0)
 100                         hi = mi;
 101                 else
 102                         lo = mi + 1;
 103         }
 104         return -lo - 1;
 105 }
 106
 107 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 108 {
 109         int pos = commit_graft_pos(graft->sha1);
 110
 111         if (0 <= pos) {
 112                 if (ignore_dups)
 113                         free(graft);
 114                 else {
 115                         free(commit_graft[pos]);
 116                         commit_graft[pos] = graft;
 117                 }
 118                 return 1;
 119         }
 120         pos = -pos - 1;
 121         if (commit_graft_alloc <= ++commit_graft_nr) {
 122                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 123                 commit_graft = xrealloc(commit_graft,
 124                                         sizeof(*commit_graft) *
 125                                         commit_graft_alloc);
 126         }
 127         if (pos < commit_graft_nr)
 128                 memmove(commit_graft + pos + 1,
 129                         commit_graft + pos,
 130                         (commit_graft_nr - pos - 1) *
 131                         sizeof(*commit_graft));
 132         commit_graft[pos] = graft;
 133         return 0;
 134 }
 135
 136 struct commit_graft *read_graft_line(char *buf, int len)
 137 {
 138         /* The format is just "Commit Parent1 Parent2 ...\n" */
 139         int i;
 140         struct commit_graft *graft = NULL;
 141
 142         if (buf[len-1] == '\n')
 143                 buf[--len] = 0;
 144         if (buf[0] == '#' || buf[0] == '\0')
 145                 return NULL;
 146         if ((len + 1) % 41) {
 147         bad_graft_data:
 148                 error("bad graft data: %s", buf);
 149                 free(graft);
 150                 return NULL;
 151         }
 152         i = (len + 1) / 41 - 1;
 153         graft = xmalloc(sizeof(*graft) + 20 * i);
 154         graft->nr_parent = i;
 155         if (get_sha1_hex(buf, graft->sha1))
 156                 goto bad_graft_data;
 157         for (i = 40; i < len; i += 41) {
 158                 if (buf[i] != ' ')
 159                         goto bad_graft_data;
 160                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 161                         goto bad_graft_data;
 162         }
 163         return graft;
 164 }
 165
 166 int read_graft_file(const char *graft_file)
 167 {
 168         FILE *fp = fopen(graft_file, "r");
 169         char buf[1024];
 170         if (!fp)
 171                 return -1;
 172         while (fgets(buf, sizeof(buf), fp)) {
 173                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 174                 int len = strlen(buf);
 175                 struct commit_graft *graft = read_graft_line(buf, len);
 176                 if (!graft)
 177                         continue;
 178                 if (register_commit_graft(graft, 1))
 179                         error("duplicate graft data: %s", buf);
 180         }
 181         fclose(fp);
 182         return 0;
 183 }
 184
 185 static void prepare_commit_graft(void)
 186 {
 187         static int commit_graft_prepared;
 188         char *graft_file;
 189
 190         if (commit_graft_prepared)
 191                 return;
 192         graft_file = get_graft_file();
 193         read_graft_file(graft_file);
 194         /* make sure shallows are read */
 195         is_repository_shallow();
 196         commit_graft_prepared = 1;
 197 }
 198
 199 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 200 {
 201         int pos;
 202         prepare_commit_graft();
 203         pos = commit_graft_pos(sha1);
 204         if (pos < 0)
 205                 return NULL;
 206         return commit_graft[pos];
 207 }
 208
 209 int write_shallow_commits(int fd, int use_pack_protocol)
 210 {
 211         int i, count = 0;
 212         for (i = 0; i < commit_graft_nr; i++)
 213                 if (commit_graft[i]->nr_parent < 0) {
 214                         const char *hex =
 215                                 sha1_to_hex(commit_graft[i]->sha1);
 216                         count++;
 217                         if (use_pack_protocol)
 218                                 packet_write(fd, "shallow %s", hex);
 219                         else {
 220                                 if (write_in_full(fd, hex,  40) != 40)
 221                                         break;
 222                                 if (write_in_full(fd, "\n", 1) != 1)
 223                                         break;
 224                         }
 225                 }
 226         return count;
 227 }
 228
 229 int unregister_shallow(const unsigned char *sha1)
 230 {
 231         int pos = commit_graft_pos(sha1);
 232         if (pos < 0)
 233                 return -1;
 234         if (pos + 1 < commit_graft_nr)
 235                 memcpy(commit_graft + pos, commit_graft + pos + 1,
 236                                 sizeof(struct commit_graft *)
 237                                 * (commit_graft_nr - pos - 1));
 238         commit_graft_nr--;
 239         return 0;
 240 }
 241
 242 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 243 {
 244         char *tail = buffer;
 245         char *bufptr = buffer;
 246         unsigned char parent[20];
 247         struct commit_list **pptr;
 248         struct commit_graft *graft;
 249         unsigned n_refs = 0;
 250
 251         if (item->object.parsed)
 252                 return 0;
 253         item->object.parsed = 1;
 254         tail += size;
 255         if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 256                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 257         if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 258                 return error("bad tree pointer in commit %s",
 259                              sha1_to_hex(item->object.sha1));
 260         item->tree = lookup_tree(parent);
 261         if (item->tree)
 262                 n_refs++;
 263         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 264         pptr = &item->parents;
 265
 266         graft = lookup_commit_graft(item->object.sha1);
 267         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 268                 struct commit *new_parent;
 269
 270                 if (tail <= bufptr + 48 ||
 271                     get_sha1_hex(bufptr + 7, parent) ||
 272                     bufptr[47] != '\n')
 273                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 274                 bufptr += 48;
 275                 if (graft)
 276                         continue;
 277                 new_parent = lookup_commit(parent);
 278                 if (new_parent) {
 279                         pptr = &commit_list_insert(new_parent, pptr)->next;
 280                         n_refs++;
 281                 }
 282         }
 283         if (graft) {
 284                 int i;
 285                 struct commit *new_parent;
 286                 for (i = 0; i < graft->nr_parent; i++) {
 287                         new_parent = lookup_commit(graft->parent[i]);
 288                         if (!new_parent)
 289                                 continue;
 290                         pptr = &commit_list_insert(new_parent, pptr)->next;
 291                         n_refs++;
 292                 }
 293         }
 294         item->date = parse_commit_date(bufptr);
 295
 296         if (track_object_refs) {
 297                 unsigned i = 0;
 298                 struct commit_list *p;
 299                 struct object_refs *refs = alloc_object_refs(n_refs);
 300                 if (item->tree)
 301                         refs->ref[i++] = &item->tree->object;
 302                 for (p = item->parents; p; p = p->next)
 303                         refs->ref[i++] = &p->item->object;
 304                 set_object_refs(&item->object, refs);
 305         }
 306
 307         return 0;
 308 }
 309
 310 int parse_commit(struct commit *item)
 311 {
 312         enum object_type type;
 313         void *buffer;
 314         unsigned long size;
 315         int ret;
 316
 317         if (item->object.parsed)
 318                 return 0;
 319         buffer = read_sha1_file(item->object.sha1, &type, &size);
 320         if (!buffer)
 321                 return error("Could not read %s",
 322                              sha1_to_hex(item->object.sha1));
 323         if (type != OBJ_COMMIT) {
 324                 free(buffer);
 325                 return error("Object %s not a commit",
 326                              sha1_to_hex(item->object.sha1));
 327         }
 328         ret = parse_commit_buffer(item, buffer, size);
 329         if (save_commit_buffer && !ret) {
 330                 item->buffer = buffer;
 331                 return 0;
 332         }
 333         free(buffer);
 334         return ret;
 335 }
 336
 337 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 338 {
 339         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 340         new_list->item = item;
 341         new_list->next = *list_p;
 342         *list_p = new_list;
 343         return new_list;
 344 }
 345
 346 void free_commit_list(struct commit_list *list)
 347 {
 348         while (list) {
 349                 struct commit_list *temp = list;
 350                 list = temp->next;
 351                 free(temp);
 352         }
 353 }
 354
 355 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 356 {
 357         struct commit_list **pp = list;
 358         struct commit_list *p;
 359         while ((p = *pp) != NULL) {
 360                 if (p->item->date < item->date) {
 361                         break;
 362                 }
 363                 pp = &p->next;
 364         }
 365         return commit_list_insert(item, pp);
 366 }
 367
 368
 369 void sort_by_date(struct commit_list **list)
 370 {
 371         struct commit_list *ret = NULL;
 372         while (*list) {
 373                 insert_by_date((*list)->item, &ret);
 374                 *list = (*list)->next;
 375         }
 376         *list = ret;
 377 }
 378
 379 struct commit *pop_most_recent_commit(struct commit_list **list,
 380                                       unsigned int mark)
 381 {
 382         struct commit *ret = (*list)->item;
 383         struct commit_list *parents = ret->parents;
 384         struct commit_list *old = *list;
 385
 386         *list = (*list)->next;
 387         free(old);
 388
 389         while (parents) {
 390                 struct commit *commit = parents->item;
 391                 parse_commit(commit);
 392                 if (!(commit->object.flags & mark)) {
 393                         commit->object.flags |= mark;
 394                         insert_by_date(commit, list);
 395                 }
 396                 parents = parents->next;
 397         }
 398         return ret;
 399 }
 400
 401 void clear_commit_marks(struct commit *commit, unsigned int mark)
 402 {
 403         while (commit) {
 404                 struct commit_list *parents;
 405
 406                 if (!(mark & commit->object.flags))
 407                         return;
 408
 409                 commit->object.flags &= ~mark;
 410
 411                 parents = commit->parents;
 412                 if (!parents)
 413                         return;
 414
 415                 while ((parents = parents->next))
 416                         clear_commit_marks(parents->item, mark);
 417
 418                 commit = commit->parents->item;
 419         }
 420 }
 421
 422 struct commit *pop_commit(struct commit_list **stack)
 423 {
 424         struct commit_list *top = *stack;
 425         struct commit *item = top ? top->item : NULL;
 426
 427         if (top) {
 428                 *stack = top->next;
 429                 free(top);
 430         }
 431         return item;
 432 }
 433
 434 void topo_sort_default_setter(struct commit *c, void *data)
 435 {
 436         c->util = data;
 437 }
 438
 439 void *topo_sort_default_getter(struct commit *c)
 440 {
 441         return c->util;
 442 }
 443
 444 /*
 445  * Performs an in-place topological sort on the list supplied.
 446  */
 447 void sort_in_topological_order(struct commit_list ** list, int lifo)
 448 {
 449         sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 450                                      topo_sort_default_getter);
 451 }
 452
 453 void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 454                                   topo_sort_set_fn_t setter,
 455                                   topo_sort_get_fn_t getter)
 456 {
 457         struct commit_list * next = *list;
 458         struct commit_list * work = NULL, **insert;
 459         struct commit_list ** pptr = list;
 460         struct sort_node * nodes;
 461         struct sort_node * next_nodes;
 462         int count = 0;
 463
 464         /* determine the size of the list */
 465         while (next) {
 466                 next = next->next;
 467                 count++;
 468         }
 469
 470         if (!count)
 471                 return;
 472         /* allocate an array to help sort the list */
 473         nodes = xcalloc(count, sizeof(*nodes));
 474         /* link the list to the array */
 475         next_nodes = nodes;
 476         next=*list;
 477         while (next) {
 478                 next_nodes->list_item = next;
 479                 setter(next->item, next_nodes);
 480                 next_nodes++;
 481                 next = next->next;
 482         }
 483         /* update the indegree */
 484         next=*list;
 485         while (next) {
 486                 struct commit_list * parents = next->item->parents;
 487                 while (parents) {
 488                         struct commit * parent=parents->item;
 489                         struct sort_node * pn = (struct sort_node *) getter(parent);
 490
 491                         if (pn)
 492                                 pn->indegree++;
 493                         parents=parents->next;
 494                 }
 495                 next=next->next;
 496         }
 497         /*
 498          * find the tips
 499          *
 500          * tips are nodes not reachable from any other node in the list
 501          *
 502          * the tips serve as a starting set for the work queue.
 503          */
 504         next=*list;
 505         insert = &work;
 506         while (next) {
 507                 struct sort_node * node = (struct sort_node *) getter(next->item);
 508
 509                 if (node->indegree == 0) {
 510                         insert = &commit_list_insert(next->item, insert)->next;
 511                 }
 512                 next=next->next;
 513         }
 514
 515         /* process the list in topological order */
 516         if (!lifo)
 517                 sort_by_date(&work);
 518         while (work) {
 519                 struct commit * work_item = pop_commit(&work);
 520                 struct sort_node * work_node = (struct sort_node *) getter(work_item);
 521                 struct commit_list * parents = work_item->parents;
 522
 523                 while (parents) {
 524                         struct commit * parent=parents->item;
 525                         struct sort_node * pn = (struct sort_node *) getter(parent);
 526
 527                         if (pn) {
 528                                 /*
 529                                  * parents are only enqueued for emission
 530                                  * when all their children have been emitted thereby
 531                                  * guaranteeing topological order.
 532                                  */
 533                                 pn->indegree--;
 534                                 if (!pn->indegree) {
 535                                         if (!lifo)
 536                                                 insert_by_date(parent, &work);
 537                                         else
 538                                                 commit_list_insert(parent, &work);
 539                                 }
 540                         }
 541                         parents=parents->next;
 542                 }
 543                 /*
 544                  * work_item is a commit all of whose children
 545                  * have already been emitted. we can emit it now.
 546                  */
 547                 *pptr = work_node->list_item;
 548                 pptr = &(*pptr)->next;
 549                 *pptr = NULL;
 550                 setter(work_item, NULL);
 551         }
 552         free(nodes);
 553 }
 554
 555 /* merge-base stuff */
 556
 557 /* bits #0..15 in revision.h */
 558 #define PARENT1         (1u<<16)
 559 #define PARENT2         (1u<<17)
 560 #define STALE           (1u<<18)
 561 #define RESULT          (1u<<19)
 562
 563 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 564
 565 static struct commit *interesting(struct commit_list *list)
 566 {
 567         while (list) {
 568                 struct commit *commit = list->item;
 569                 list = list->next;
 570                 if (commit->object.flags & STALE)
 571                         continue;
 572                 return commit;
 573         }
 574         return NULL;
 575 }
 576
 577 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 578 {
 579         struct commit_list *list = NULL;
 580         struct commit_list *result = NULL;
 581
 582         if (one == two)
 583                 /* We do not mark this even with RESULT so we do not
 584                  * have to clean it up.
 585                  */
 586                 return commit_list_insert(one, &result);
 587
 588         parse_commit(one);
 589         parse_commit(two);
 590
 591         one->object.flags |= PARENT1;
 592         two->object.flags |= PARENT2;
 593         insert_by_date(one, &list);
 594         insert_by_date(two, &list);
 595
 596         while (interesting(list)) {
 597                 struct commit *commit;
 598                 struct commit_list *parents;
 599                 struct commit_list *n;
 600                 int flags;
 601
 602                 commit = list->item;
 603                 n = list->next;
 604                 free(list);
 605                 list = n;
 606
 607                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 608                 if (flags == (PARENT1 | PARENT2)) {
 609                         if (!(commit->object.flags & RESULT)) {
 610                                 commit->object.flags |= RESULT;
 611                                 insert_by_date(commit, &result);
 612                         }
 613                         /* Mark parents of a found merge stale */
 614                         flags |= STALE;
 615                 }
 616                 parents = commit->parents;
 617                 while (parents) {
 618                         struct commit *p = parents->item;
 619                         parents = parents->next;
 620                         if ((p->object.flags & flags) == flags)
 621                                 continue;
 622                         parse_commit(p);
 623                         p->object.flags |= flags;
 624                         insert_by_date(p, &list);
 625                 }
 626         }
 627
 628         /* Clean up the result to remove stale ones */
 629         free_commit_list(list);
 630         list = result; result = NULL;
 631         while (list) {
 632                 struct commit_list *n = list->next;
 633                 if (!(list->item->object.flags & STALE))
 634                         insert_by_date(list->item, &result);
 635                 free(list);
 636                 list = n;
 637         }
 638         return result;
 639 }
 640
 641 struct commit_list *get_merge_bases(struct commit *one,
 642                                         struct commit *two, int cleanup)
 643 {
 644         struct commit_list *list;
 645         struct commit **rslt;
 646         struct commit_list *result;
 647         int cnt, i, j;
 648
 649         result = merge_bases(one, two);
 650         if (one == two)
 651                 return result;
 652         if (!result || !result->next) {
 653                 if (cleanup) {
 654                         clear_commit_marks(one, all_flags);
 655                         clear_commit_marks(two, all_flags);
 656                 }
 657                 return result;
 658         }
 659
 660         /* There are more than one */
 661         cnt = 0;
 662         list = result;
 663         while (list) {
 664                 list = list->next;
 665                 cnt++;
 666         }
 667         rslt = xcalloc(cnt, sizeof(*rslt));
 668         for (list = result, i = 0; list; list = list->next)
 669                 rslt[i++] = list->item;
 670         free_commit_list(result);
 671
 672         clear_commit_marks(one, all_flags);
 673         clear_commit_marks(two, all_flags);
 674         for (i = 0; i < cnt - 1; i++) {
 675                 for (j = i+1; j < cnt; j++) {
 676                         if (!rslt[i] || !rslt[j])
 677                                 continue;
 678                         result = merge_bases(rslt[i], rslt[j]);
 679                         clear_commit_marks(rslt[i], all_flags);
 680                         clear_commit_marks(rslt[j], all_flags);
 681                         for (list = result; list; list = list->next) {
 682                                 if (rslt[i] == list->item)
 683                                         rslt[i] = NULL;
 684                                 if (rslt[j] == list->item)
 685                                         rslt[j] = NULL;
 686                         }
 687                 }
 688         }
 689
 690         /* Surviving ones in rslt[] are the independent results */
 691         result = NULL;
 692         for (i = 0; i < cnt; i++) {
 693                 if (rslt[i])
 694                         insert_by_date(rslt[i], &result);
 695         }
 696         free(rslt);
 697         return result;
 698 }
 699
 700 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 701 {
 702         struct commit_list *bases, *b;
 703         int ret = 0;
 704
 705         if (num == 1)
 706                 bases = get_merge_bases(commit, *reference, 1);
 707         else
 708                 die("not yet");
 709         for (b = bases; b; b = b->next) {
 710                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 711                         ret = 1;
 712                         break;
 713                 }
 714         }
 715
 716         free_commit_list(bases);
 717         return ret;
 718 }