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 #include "notes.h"
   9 #include "gpg-interface.h"
  10
  11 int save_commit_buffer = 1;
  12
  13 const char *commit_type = "commit";
  14
  15 static struct commit *check_commit(struct object *obj,
  16                                    const unsigned char *sha1,
  17                                    int quiet)
  18 {
  19         if (obj->type != OBJ_COMMIT) {
  20                 if (!quiet)
  21                         error("Object %s is a %s, not a commit",
  22                               sha1_to_hex(sha1), typename(obj->type));
  23                 return NULL;
  24         }
  25         return (struct commit *) obj;
  26 }
  27
  28 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  29                                               int quiet)
  30 {
  31         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  32
  33         if (!obj)
  34                 return NULL;
  35         return check_commit(obj, sha1, quiet);
  36 }
  37
  38 struct commit *lookup_commit_reference(const unsigned char *sha1)
  39 {
  40         return lookup_commit_reference_gently(sha1, 0);
  41 }
  42
  43 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  44 {
  45         struct commit *c = lookup_commit_reference(sha1);
  46         if (!c)
  47                 die(_("could not parse %s"), ref_name);
  48         if (hashcmp(sha1, c->object.sha1)) {
  49                 warning(_("%s %s is not a commit!"),
  50                         ref_name, sha1_to_hex(sha1));
  51         }
  52         return c;
  53 }
  54
  55 struct commit *lookup_commit(const unsigned char *sha1)
  56 {
  57         struct object *obj = lookup_object(sha1);
  58         if (!obj)
  59                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  60         if (!obj->type)
  61                 obj->type = OBJ_COMMIT;
  62         return check_commit(obj, sha1, 0);
  63 }
  64
  65 struct commit *lookup_commit_reference_by_name(const char *name)
  66 {
  67         unsigned char sha1[20];
  68         struct commit *commit;
  69
  70         if (get_sha1(name, sha1))
  71                 return NULL;
  72         commit = lookup_commit_reference(sha1);
  73         if (!commit || parse_commit(commit))
  74                 return NULL;
  75         return commit;
  76 }
  77
  78 static unsigned long parse_commit_date(const char *buf, const char *tail)
  79 {
  80         const char *dateptr;
  81
  82         if (buf + 6 >= tail)
  83                 return 0;
  84         if (memcmp(buf, "author", 6))
  85                 return 0;
  86         while (buf < tail && *buf++ != '\n')
  87                 /* nada */;
  88         if (buf + 9 >= tail)
  89                 return 0;
  90         if (memcmp(buf, "committer", 9))
  91                 return 0;
  92         while (buf < tail && *buf++ != '>')
  93                 /* nada */;
  94         if (buf >= tail)
  95                 return 0;
  96         dateptr = buf;
  97         while (buf < tail && *buf++ != '\n')
  98                 /* nada */;
  99         if (buf >= tail)
 100                 return 0;
 101         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 102         return strtoul(dateptr, NULL, 10);
 103 }
 104
 105 static struct commit_graft **commit_graft;
 106 static int commit_graft_alloc, commit_graft_nr;
 107
 108 static int commit_graft_pos(const unsigned char *sha1)
 109 {
 110         int lo, hi;
 111         lo = 0;
 112         hi = commit_graft_nr;
 113         while (lo < hi) {
 114                 int mi = (lo + hi) / 2;
 115                 struct commit_graft *graft = commit_graft[mi];
 116                 int cmp = hashcmp(sha1, graft->sha1);
 117                 if (!cmp)
 118                         return mi;
 119                 if (cmp < 0)
 120                         hi = mi;
 121                 else
 122                         lo = mi + 1;
 123         }
 124         return -lo - 1;
 125 }
 126
 127 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 128 {
 129         int pos = commit_graft_pos(graft->sha1);
 130
 131         if (0 <= pos) {
 132                 if (ignore_dups)
 133                         free(graft);
 134                 else {
 135                         free(commit_graft[pos]);
 136                         commit_graft[pos] = graft;
 137                 }
 138                 return 1;
 139         }
 140         pos = -pos - 1;
 141         if (commit_graft_alloc <= ++commit_graft_nr) {
 142                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 143                 commit_graft = xrealloc(commit_graft,
 144                                         sizeof(*commit_graft) *
 145                                         commit_graft_alloc);
 146         }
 147         if (pos < commit_graft_nr)
 148                 memmove(commit_graft + pos + 1,
 149                         commit_graft + pos,
 150                         (commit_graft_nr - pos - 1) *
 151                         sizeof(*commit_graft));
 152         commit_graft[pos] = graft;
 153         return 0;
 154 }
 155
 156 struct commit_graft *read_graft_line(char *buf, int len)
 157 {
 158         /* The format is just "Commit Parent1 Parent2 ...\n" */
 159         int i;
 160         struct commit_graft *graft = NULL;
 161
 162         while (len && isspace(buf[len-1]))
 163                 buf[--len] = '\0';
 164         if (buf[0] == '#' || buf[0] == '\0')
 165                 return NULL;
 166         if ((len + 1) % 41)
 167                 goto bad_graft_data;
 168         i = (len + 1) / 41 - 1;
 169         graft = xmalloc(sizeof(*graft) + 20 * i);
 170         graft->nr_parent = i;
 171         if (get_sha1_hex(buf, graft->sha1))
 172                 goto bad_graft_data;
 173         for (i = 40; i < len; i += 41) {
 174                 if (buf[i] != ' ')
 175                         goto bad_graft_data;
 176                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 177                         goto bad_graft_data;
 178         }
 179         return graft;
 180
 181 bad_graft_data:
 182         error("bad graft data: %s", buf);
 183         free(graft);
 184         return NULL;
 185 }
 186
 187 static int read_graft_file(const char *graft_file)
 188 {
 189         FILE *fp = fopen(graft_file, "r");
 190         char buf[1024];
 191         if (!fp)
 192                 return -1;
 193         while (fgets(buf, sizeof(buf), fp)) {
 194                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 195                 int len = strlen(buf);
 196                 struct commit_graft *graft = read_graft_line(buf, len);
 197                 if (!graft)
 198                         continue;
 199                 if (register_commit_graft(graft, 1))
 200                         error("duplicate graft data: %s", buf);
 201         }
 202         fclose(fp);
 203         return 0;
 204 }
 205
 206 static void prepare_commit_graft(void)
 207 {
 208         static int commit_graft_prepared;
 209         char *graft_file;
 210
 211         if (commit_graft_prepared)
 212                 return;
 213         graft_file = get_graft_file();
 214         read_graft_file(graft_file);
 215         /* make sure shallows are read */
 216         is_repository_shallow();
 217         commit_graft_prepared = 1;
 218 }
 219
 220 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 221 {
 222         int pos;
 223         prepare_commit_graft();
 224         pos = commit_graft_pos(sha1);
 225         if (pos < 0)
 226                 return NULL;
 227         return commit_graft[pos];
 228 }
 229
 230 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 231 {
 232         int i, ret;
 233         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 234                 ret = fn(commit_graft[i], cb_data);
 235         return ret;
 236 }
 237
 238 int unregister_shallow(const unsigned char *sha1)
 239 {
 240         int pos = commit_graft_pos(sha1);
 241         if (pos < 0)
 242                 return -1;
 243         if (pos + 1 < commit_graft_nr)
 244                 memmove(commit_graft + pos, commit_graft + pos + 1,
 245                                 sizeof(struct commit_graft *)
 246                                 * (commit_graft_nr - pos - 1));
 247         commit_graft_nr--;
 248         return 0;
 249 }
 250
 251 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 252 {
 253         const char *tail = buffer;
 254         const char *bufptr = buffer;
 255         unsigned char parent[20];
 256         struct commit_list **pptr;
 257         struct commit_graft *graft;
 258
 259         if (item->object.parsed)
 260                 return 0;
 261         item->object.parsed = 1;
 262         tail += size;
 263         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 264                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 265         if (get_sha1_hex(bufptr + 5, parent) < 0)
 266                 return error("bad tree pointer in commit %s",
 267                              sha1_to_hex(item->object.sha1));
 268         item->tree = lookup_tree(parent);
 269         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 270         pptr = &item->parents;
 271
 272         graft = lookup_commit_graft(item->object.sha1);
 273         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 274                 struct commit *new_parent;
 275
 276                 if (tail <= bufptr + 48 ||
 277                     get_sha1_hex(bufptr + 7, parent) ||
 278                     bufptr[47] != '\n')
 279                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 280                 bufptr += 48;
 281                 /*
 282                  * The clone is shallow if nr_parent < 0, and we must
 283                  * not traverse its real parents even when we unhide them.
 284                  */
 285                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 286                         continue;
 287                 new_parent = lookup_commit(parent);
 288                 if (new_parent)
 289                         pptr = &commit_list_insert(new_parent, pptr)->next;
 290         }
 291         if (graft) {
 292                 int i;
 293                 struct commit *new_parent;
 294                 for (i = 0; i < graft->nr_parent; i++) {
 295                         new_parent = lookup_commit(graft->parent[i]);
 296                         if (!new_parent)
 297                                 continue;
 298                         pptr = &commit_list_insert(new_parent, pptr)->next;
 299                 }
 300         }
 301         item->date = parse_commit_date(bufptr, tail);
 302
 303         return 0;
 304 }
 305
 306 int parse_commit(struct commit *item)
 307 {
 308         enum object_type type;
 309         void *buffer;
 310         unsigned long size;
 311         int ret;
 312
 313         if (!item)
 314                 return -1;
 315         if (item->object.parsed)
 316                 return 0;
 317         buffer = read_sha1_file(item->object.sha1, &type, &size);
 318         if (!buffer)
 319                 return error("Could not read %s",
 320                              sha1_to_hex(item->object.sha1));
 321         if (type != OBJ_COMMIT) {
 322                 free(buffer);
 323                 return error("Object %s not a commit",
 324                              sha1_to_hex(item->object.sha1));
 325         }
 326         ret = parse_commit_buffer(item, buffer, size);
 327         if (save_commit_buffer && !ret) {
 328                 item->buffer = buffer;
 329                 return 0;
 330         }
 331         free(buffer);
 332         return ret;
 333 }
 334
 335 int find_commit_subject(const char *commit_buffer, const char **subject)
 336 {
 337         const char *eol;
 338         const char *p = commit_buffer;
 339
 340         while (*p && (*p != '\n' || p[1] != '\n'))
 341                 p++;
 342         if (*p) {
 343                 p += 2;
 344                 for (eol = p; *eol && *eol != '\n'; eol++)
 345                         ; /* do nothing */
 346         } else
 347                 eol = p;
 348
 349         *subject = p;
 350
 351         return eol - p;
 352 }
 353
 354 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 355 {
 356         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 357         new_list->item = item;
 358         new_list->next = *list_p;
 359         *list_p = new_list;
 360         return new_list;
 361 }
 362
 363 unsigned commit_list_count(const struct commit_list *l)
 364 {
 365         unsigned c = 0;
 366         for (; l; l = l->next )
 367                 c++;
 368         return c;
 369 }
 370
 371 void free_commit_list(struct commit_list *list)
 372 {
 373         while (list) {
 374                 struct commit_list *temp = list;
 375                 list = temp->next;
 376                 free(temp);
 377         }
 378 }
 379
 380 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 381 {
 382         struct commit_list **pp = list;
 383         struct commit_list *p;
 384         while ((p = *pp) != NULL) {
 385                 if (p->item->date < item->date) {
 386                         break;
 387                 }
 388                 pp = &p->next;
 389         }
 390         return commit_list_insert(item, pp);
 391 }
 392
 393
 394 void commit_list_sort_by_date(struct commit_list **list)
 395 {
 396         struct commit_list *ret = NULL;
 397         while (*list) {
 398                 commit_list_insert_by_date((*list)->item, &ret);
 399                 *list = (*list)->next;
 400         }
 401         *list = ret;
 402 }
 403
 404 struct commit *pop_most_recent_commit(struct commit_list **list,
 405                                       unsigned int mark)
 406 {
 407         struct commit *ret = (*list)->item;
 408         struct commit_list *parents = ret->parents;
 409         struct commit_list *old = *list;
 410
 411         *list = (*list)->next;
 412         free(old);
 413
 414         while (parents) {
 415                 struct commit *commit = parents->item;
 416                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 417                         commit->object.flags |= mark;
 418                         commit_list_insert_by_date(commit, list);
 419                 }
 420                 parents = parents->next;
 421         }
 422         return ret;
 423 }
 424
 425 static void clear_commit_marks_1(struct commit_list **plist,
 426                                  struct commit *commit, unsigned int mark)
 427 {
 428         while (commit) {
 429                 struct commit_list *parents;
 430
 431                 if (!(mark & commit->object.flags))
 432                         return;
 433
 434                 commit->object.flags &= ~mark;
 435
 436                 parents = commit->parents;
 437                 if (!parents)
 438                         return;
 439
 440                 while ((parents = parents->next))
 441                         commit_list_insert(parents->item, plist);
 442
 443                 commit = commit->parents->item;
 444         }
 445 }
 446
 447 void clear_commit_marks(struct commit *commit, unsigned int mark)
 448 {
 449         struct commit_list *list = NULL;
 450         commit_list_insert(commit, &list);
 451         while (list)
 452                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 453 }
 454
 455 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 456 {
 457         struct object *object;
 458         struct commit *commit;
 459         unsigned int i;
 460
 461         for (i = 0; i < a->nr; i++) {
 462                 object = a->objects[i].item;
 463                 commit = lookup_commit_reference_gently(object->sha1, 1);
 464                 if (commit)
 465                         clear_commit_marks(commit, mark);
 466         }
 467 }
 468
 469 struct commit *pop_commit(struct commit_list **stack)
 470 {
 471         struct commit_list *top = *stack;
 472         struct commit *item = top ? top->item : NULL;
 473
 474         if (top) {
 475                 *stack = top->next;
 476                 free(top);
 477         }
 478         return item;
 479 }
 480
 481 /*
 482  * Performs an in-place topological sort on the list supplied.
 483  */
 484 void sort_in_topological_order(struct commit_list ** list, int lifo)
 485 {
 486         struct commit_list *next, *orig = *list;
 487         struct commit_list *work, **insert;
 488         struct commit_list **pptr;
 489
 490         if (!orig)
 491                 return;
 492         *list = NULL;
 493
 494         /* Mark them and clear the indegree */
 495         for (next = orig; next; next = next->next) {
 496                 struct commit *commit = next->item;
 497                 commit->indegree = 1;
 498         }
 499
 500         /* update the indegree */
 501         for (next = orig; next; next = next->next) {
 502                 struct commit_list * parents = next->item->parents;
 503                 while (parents) {
 504                         struct commit *parent = parents->item;
 505
 506                         if (parent->indegree)
 507                                 parent->indegree++;
 508                         parents = parents->next;
 509                 }
 510         }
 511
 512         /*
 513          * find the tips
 514          *
 515          * tips are nodes not reachable from any other node in the list
 516          *
 517          * the tips serve as a starting set for the work queue.
 518          */
 519         work = NULL;
 520         insert = &work;
 521         for (next = orig; next; next = next->next) {
 522                 struct commit *commit = next->item;
 523
 524                 if (commit->indegree == 1)
 525                         insert = &commit_list_insert(commit, insert)->next;
 526         }
 527
 528         /* process the list in topological order */
 529         if (!lifo)
 530                 commit_list_sort_by_date(&work);
 531
 532         pptr = list;
 533         *list = NULL;
 534         while (work) {
 535                 struct commit *commit;
 536                 struct commit_list *parents, *work_item;
 537
 538                 work_item = work;
 539                 work = work_item->next;
 540                 work_item->next = NULL;
 541
 542                 commit = work_item->item;
 543                 for (parents = commit->parents; parents ; parents = parents->next) {
 544                         struct commit *parent = parents->item;
 545
 546                         if (!parent->indegree)
 547                                 continue;
 548
 549                         /*
 550                          * parents are only enqueued for emission
 551                          * when all their children have been emitted thereby
 552                          * guaranteeing topological order.
 553                          */
 554                         if (--parent->indegree == 1) {
 555                                 if (!lifo)
 556                                         commit_list_insert_by_date(parent, &work);
 557                                 else
 558                                         commit_list_insert(parent, &work);
 559                         }
 560                 }
 561                 /*
 562                  * work_item is a commit all of whose children
 563                  * have already been emitted. we can emit it now.
 564                  */
 565                 commit->indegree = 0;
 566                 *pptr = work_item;
 567                 pptr = &work_item->next;
 568         }
 569 }
 570
 571 /* merge-base stuff */
 572
 573 /* bits #0..15 in revision.h */
 574 #define PARENT1         (1u<<16)
 575 #define PARENT2         (1u<<17)
 576 #define STALE           (1u<<18)
 577 #define RESULT          (1u<<19)
 578
 579 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 580
 581 static struct commit *interesting(struct commit_list *list)
 582 {
 583         while (list) {
 584                 struct commit *commit = list->item;
 585                 list = list->next;
 586                 if (commit->object.flags & STALE)
 587                         continue;
 588                 return commit;
 589         }
 590         return NULL;
 591 }
 592
 593 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 594 {
 595         struct commit_list *list = NULL;
 596         struct commit_list *result = NULL;
 597         int i;
 598
 599         for (i = 0; i < n; i++) {
 600                 if (one == twos[i])
 601                         /*
 602                          * We do not mark this even with RESULT so we do not
 603                          * have to clean it up.
 604                          */
 605                         return commit_list_insert(one, &result);
 606         }
 607
 608         if (parse_commit(one))
 609                 return NULL;
 610         for (i = 0; i < n; i++) {
 611                 if (parse_commit(twos[i]))
 612                         return NULL;
 613         }
 614
 615         one->object.flags |= PARENT1;
 616         commit_list_insert_by_date(one, &list);
 617         for (i = 0; i < n; i++) {
 618                 twos[i]->object.flags |= PARENT2;
 619                 commit_list_insert_by_date(twos[i], &list);
 620         }
 621
 622         while (interesting(list)) {
 623                 struct commit *commit;
 624                 struct commit_list *parents;
 625                 struct commit_list *next;
 626                 int flags;
 627
 628                 commit = list->item;
 629                 next = list->next;
 630                 free(list);
 631                 list = next;
 632
 633                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 634                 if (flags == (PARENT1 | PARENT2)) {
 635                         if (!(commit->object.flags & RESULT)) {
 636                                 commit->object.flags |= RESULT;
 637                                 commit_list_insert_by_date(commit, &result);
 638                         }
 639                         /* Mark parents of a found merge stale */
 640                         flags |= STALE;
 641                 }
 642                 parents = commit->parents;
 643                 while (parents) {
 644                         struct commit *p = parents->item;
 645                         parents = parents->next;
 646                         if ((p->object.flags & flags) == flags)
 647                                 continue;
 648                         if (parse_commit(p))
 649                                 return NULL;
 650                         p->object.flags |= flags;
 651                         commit_list_insert_by_date(p, &list);
 652                 }
 653         }
 654
 655         /* Clean up the result to remove stale ones */
 656         free_commit_list(list);
 657         list = result; result = NULL;
 658         while (list) {
 659                 struct commit_list *next = list->next;
 660                 if (!(list->item->object.flags & STALE))
 661                         commit_list_insert_by_date(list->item, &result);
 662                 free(list);
 663                 list = next;
 664         }
 665         return result;
 666 }
 667
 668 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 669 {
 670         struct commit_list *i, *j, *k, *ret = NULL;
 671         struct commit_list **pptr = &ret;
 672
 673         for (i = in; i; i = i->next) {
 674                 if (!ret)
 675                         pptr = &commit_list_insert(i->item, pptr)->next;
 676                 else {
 677                         struct commit_list *new = NULL, *end = NULL;
 678
 679                         for (j = ret; j; j = j->next) {
 680                                 struct commit_list *bases;
 681                                 bases = get_merge_bases(i->item, j->item, 1);
 682                                 if (!new)
 683                                         new = bases;
 684                                 else
 685                                         end->next = bases;
 686                                 for (k = bases; k; k = k->next)
 687                                         end = k;
 688                         }
 689                         ret = new;
 690                 }
 691         }
 692         return ret;
 693 }
 694
 695 struct commit_list *get_merge_bases_many(struct commit *one,
 696                                          int n,
 697                                          struct commit **twos,
 698                                          int cleanup)
 699 {
 700         struct commit_list *list;
 701         struct commit **rslt;
 702         struct commit_list *result;
 703         int cnt, i, j;
 704
 705         result = merge_bases_many(one, n, twos);
 706         for (i = 0; i < n; i++) {
 707                 if (one == twos[i])
 708                         return result;
 709         }
 710         if (!result || !result->next) {
 711                 if (cleanup) {
 712                         clear_commit_marks(one, all_flags);
 713                         for (i = 0; i < n; i++)
 714                                 clear_commit_marks(twos[i], all_flags);
 715                 }
 716                 return result;
 717         }
 718
 719         /* There are more than one */
 720         cnt = 0;
 721         list = result;
 722         while (list) {
 723                 list = list->next;
 724                 cnt++;
 725         }
 726         rslt = xcalloc(cnt, sizeof(*rslt));
 727         for (list = result, i = 0; list; list = list->next)
 728                 rslt[i++] = list->item;
 729         free_commit_list(result);
 730
 731         clear_commit_marks(one, all_flags);
 732         for (i = 0; i < n; i++)
 733                 clear_commit_marks(twos[i], all_flags);
 734         for (i = 0; i < cnt - 1; i++) {
 735                 for (j = i+1; j < cnt; j++) {
 736                         if (!rslt[i] || !rslt[j])
 737                                 continue;
 738                         result = merge_bases_many(rslt[i], 1, &rslt[j]);
 739                         clear_commit_marks(rslt[i], all_flags);
 740                         clear_commit_marks(rslt[j], all_flags);
 741                         for (list = result; list; list = list->next) {
 742                                 if (rslt[i] == list->item)
 743                                         rslt[i] = NULL;
 744                                 if (rslt[j] == list->item)
 745                                         rslt[j] = NULL;
 746                         }
 747                 }
 748         }
 749
 750         /* Surviving ones in rslt[] are the independent results */
 751         result = NULL;
 752         for (i = 0; i < cnt; i++) {
 753                 if (rslt[i])
 754                         commit_list_insert_by_date(rslt[i], &result);
 755         }
 756         free(rslt);
 757         return result;
 758 }
 759
 760 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 761                                     int cleanup)
 762 {
 763         return get_merge_bases_many(one, 1, &two, cleanup);
 764 }
 765
 766 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 767 {
 768         if (!with_commit)
 769                 return 1;
 770         while (with_commit) {
 771                 struct commit *other;
 772
 773                 other = with_commit->item;
 774                 with_commit = with_commit->next;
 775                 if (in_merge_bases(other, &commit, 1))
 776                         return 1;
 777         }
 778         return 0;
 779 }
 780
 781 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 782 {
 783         struct commit_list *bases, *b;
 784         int ret = 0;
 785
 786         if (num == 1)
 787                 bases = get_merge_bases(commit, *reference, 1);
 788         else
 789                 die("not yet");
 790         for (b = bases; b; b = b->next) {
 791                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 792                         ret = 1;
 793                         break;
 794                 }
 795         }
 796
 797         free_commit_list(bases);
 798         return ret;
 799 }
 800
 801 struct commit_list *reduce_heads(struct commit_list *heads)
 802 {
 803         struct commit_list *p;
 804         struct commit_list *result = NULL, **tail = &result;
 805         struct commit **other;
 806         size_t num_head, num_other;
 807
 808         if (!heads)
 809                 return NULL;
 810
 811         /* Avoid unnecessary reallocations */
 812         for (p = heads, num_head = 0; p; p = p->next)
 813                 num_head++;
 814         other = xcalloc(sizeof(*other), num_head);
 815
 816         /* For each commit, see if it can be reached by others */
 817         for (p = heads; p; p = p->next) {
 818                 struct commit_list *q, *base;
 819
 820                 /* Do we already have this in the result? */
 821                 for (q = result; q; q = q->next)
 822                         if (p->item == q->item)
 823                                 break;
 824                 if (q)
 825                         continue;
 826
 827                 num_other = 0;
 828                 for (q = heads; q; q = q->next) {
 829                         if (p->item == q->item)
 830                                 continue;
 831                         other[num_other++] = q->item;
 832                 }
 833                 if (num_other)
 834                         base = get_merge_bases_many(p->item, num_other, other, 1);
 835                 else
 836                         base = NULL;
 837                 /*
 838                  * If p->item does not have anything common with other
 839                  * commits, there won't be any merge base.  If it is
 840                  * reachable from some of the others, p->item will be
 841                  * the merge base.  If its history is connected with
 842                  * others, but p->item is not reachable by others, we
 843                  * will get something other than p->item back.
 844                  */
 845                 if (!base || (base->item != p->item))
 846                         tail = &(commit_list_insert(p->item, tail)->next);
 847                 free_commit_list(base);
 848         }
 849         free(other);
 850         return result;
 851 }
 852
 853 static const char gpg_sig_header[] = "gpgsig";
 854 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 855
 856 static int do_sign_commit(struct strbuf *buf, const char *keyid)
 857 {
 858         struct strbuf sig = STRBUF_INIT;
 859         int inspos, copypos;
 860
 861         /* find the end of the header */
 862         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
 863
 864         if (!keyid || !*keyid)
 865                 keyid = get_signing_key();
 866         if (sign_buffer(buf, &sig, keyid)) {
 867                 strbuf_release(&sig);
 868                 return -1;
 869         }
 870
 871         for (copypos = 0; sig.buf[copypos]; ) {
 872                 const char *bol = sig.buf + copypos;
 873                 const char *eol = strchrnul(bol, '\n');
 874                 int len = (eol - bol) + !!*eol;
 875
 876                 if (!copypos) {
 877                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 878                         inspos += gpg_sig_header_len;
 879                 }
 880                 strbuf_insert(buf, inspos++, " ", 1);
 881                 strbuf_insert(buf, inspos, bol, len);
 882                 inspos += len;
 883                 copypos += len;
 884         }
 885         strbuf_release(&sig);
 886         return 0;
 887 }
 888
 889 int parse_signed_commit(const unsigned char *sha1,
 890                         struct strbuf *payload, struct strbuf *signature)
 891 {
 892         unsigned long size;
 893         enum object_type type;
 894         char *buffer = read_sha1_file(sha1, &type, &size);
 895         int in_signature, saw_signature = -1;
 896         char *line, *tail;
 897
 898         if (!buffer || type != OBJ_COMMIT)
 899                 goto cleanup;
 900
 901         line = buffer;
 902         tail = buffer + size;
 903         in_signature = 0;
 904         saw_signature = 0;
 905         while (line < tail) {
 906                 const char *sig = NULL;
 907                 char *next = memchr(line, '\n', tail - line);
 908
 909                 next = next ? next + 1 : tail;
 910                 if (in_signature && line[0] == ' ')
 911                         sig = line + 1;
 912                 else if (!prefixcmp(line, gpg_sig_header) &&
 913                          line[gpg_sig_header_len] == ' ')
 914                         sig = line + gpg_sig_header_len + 1;
 915                 if (sig) {
 916                         strbuf_add(signature, sig, next - sig);
 917                         saw_signature = 1;
 918                         in_signature = 1;
 919                 } else {
 920                         if (*line == '\n')
 921                                 /* dump the whole remainder of the buffer */
 922                                 next = tail;
 923                         strbuf_add(payload, line, next - line);
 924                         in_signature = 0;
 925                 }
 926                 line = next;
 927         }
 928  cleanup:
 929         free(buffer);
 930         return saw_signature;
 931 }
 932
 933 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 934 {
 935         struct merge_remote_desc *desc;
 936         struct commit_extra_header *mergetag;
 937         char *buf;
 938         unsigned long size, len;
 939         enum object_type type;
 940
 941         desc = merge_remote_util(parent);
 942         if (!desc || !desc->obj)
 943                 return;
 944         buf = read_sha1_file(desc->obj->sha1, &type, &size);
 945         if (!buf || type != OBJ_TAG)
 946                 goto free_return;
 947         len = parse_signature(buf, size);
 948         if (size == len)
 949                 goto free_return;
 950         /*
 951          * We could verify this signature and either omit the tag when
 952          * it does not validate, but the integrator may not have the
 953          * public key of the signer of the tag he is merging, while a
 954          * later auditor may have it while auditing, so let's not run
 955          * verify-signed-buffer here for now...
 956          *
 957          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
 958          *      warn("warning: signed tag unverified.");
 959          */
 960         mergetag = xcalloc(1, sizeof(*mergetag));
 961         mergetag->key = xstrdup("mergetag");
 962         mergetag->value = buf;
 963         mergetag->len = size;
 964
 965         **tail = mergetag;
 966         *tail = &mergetag->next;
 967         return;
 968
 969 free_return:
 970         free(buf);
 971 }
 972
 973 void append_merge_tag_headers(struct commit_list *parents,
 974                               struct commit_extra_header ***tail)
 975 {
 976         while (parents) {
 977                 struct commit *parent = parents->item;
 978                 handle_signed_tag(parent, tail);
 979                 parents = parents->next;
 980         }
 981 }
 982
 983 static void add_extra_header(struct strbuf *buffer,
 984                              struct commit_extra_header *extra)
 985 {
 986         strbuf_addstr(buffer, extra->key);
 987         if (extra->len)
 988                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
 989         else
 990                 strbuf_addch(buffer, '\n');
 991 }
 992
 993 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
 994                                                       const char **exclude)
 995 {
 996         struct commit_extra_header *extra = NULL;
 997         unsigned long size;
 998         enum object_type type;
 999         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1000         if (buffer && type == OBJ_COMMIT)
1001                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1002         free(buffer);
1003         return extra;
1004 }
1005
1006 static inline int standard_header_field(const char *field, size_t len)
1007 {
1008         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1009                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1010                 (len == 6 && !memcmp(field, "author ", 7)) ||
1011                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1012                 (len == 8 && !memcmp(field, "encoding ", 9)));
1013 }
1014
1015 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1016 {
1017         if (!exclude)
1018                 return 0;
1019
1020         while (*exclude) {
1021                 size_t xlen = strlen(*exclude);
1022                 if (len == xlen &&
1023                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1024                         return 1;
1025                 exclude++;
1026         }
1027         return 0;
1028 }
1029
1030 struct commit_extra_header *read_commit_extra_header_lines(const char *buffer, size_t size,
1031                                                            const char **exclude)
1032 {
1033         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1034         const char *line, *next, *eof, *eob;
1035         struct strbuf buf = STRBUF_INIT;
1036
1037         for (line = buffer, eob = line + size;
1038              line < eob && *line != '\n';
1039              line = next) {
1040                 next = memchr(line, '\n', eob - line);
1041                 next = next ? next + 1 : eob;
1042                 if (*line == ' ') {
1043                         /* continuation */
1044                         if (it)
1045                                 strbuf_add(&buf, line + 1, next - (line + 1));
1046                         continue;
1047                 }
1048                 if (it)
1049                         it->value = strbuf_detach(&buf, &it->len);
1050                 strbuf_reset(&buf);
1051                 it = NULL;
1052
1053                 eof = strchr(line, ' ');
1054                 if (next <= eof)
1055                         eof = next;
1056
1057                 if (standard_header_field(line, eof - line) ||
1058                     excluded_header_field(line, eof - line, exclude))
1059                         continue;
1060
1061                 it = xcalloc(1, sizeof(*it));
1062                 it->key = xmemdupz(line, eof-line);
1063                 *tail = it;
1064                 tail = &it->next;
1065                 if (eof + 1 < next)
1066                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1067         }
1068         if (it)
1069                 it->value = strbuf_detach(&buf, &it->len);
1070         return extra;
1071 }
1072
1073 void free_commit_extra_headers(struct commit_extra_header *extra)
1074 {
1075         while (extra) {
1076                 struct commit_extra_header *next = extra->next;
1077                 free(extra->key);
1078                 free(extra->value);
1079                 free(extra);
1080                 extra = next;
1081         }
1082 }
1083
1084 int commit_tree(const struct strbuf *msg, unsigned char *tree,
1085                 struct commit_list *parents, unsigned char *ret,
1086                 const char *author, const char *sign_commit)
1087 {
1088         struct commit_extra_header *extra = NULL, **tail = &extra;
1089         int result;
1090
1091         append_merge_tag_headers(parents, &tail);
1092         result = commit_tree_extended(msg, tree, parents, ret,
1093                                       author, sign_commit, extra);
1094         free_commit_extra_headers(extra);
1095         return result;
1096 }
1097
1098 static const char commit_utf8_warn[] =
1099 "Warning: commit message does not conform to UTF-8.\n"
1100 "You may want to amend it after fixing the message, or set the config\n"
1101 "variable i18n.commitencoding to the encoding your project uses.\n";
1102
1103 int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1104                          struct commit_list *parents, unsigned char *ret,
1105                          const char *author, const char *sign_commit,
1106                          struct commit_extra_header *extra)
1107 {
1108         int result;
1109         int encoding_is_utf8;
1110         struct strbuf buffer;
1111
1112         assert_sha1_type(tree, OBJ_TREE);
1113
1114         if (memchr(msg->buf, '\0', msg->len))
1115                 return error("a NUL byte in commit log message not allowed.");
1116
1117         /* Not having i18n.commitencoding is the same as having utf-8 */
1118         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1119
1120         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1121         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1122
1123         /*
1124          * NOTE! This ordering means that the same exact tree merged with a
1125          * different order of parents will be a _different_ changeset even
1126          * if everything else stays the same.
1127          */
1128         while (parents) {
1129                 struct commit_list *next = parents->next;
1130                 struct commit *parent = parents->item;
1131
1132                 strbuf_addf(&buffer, "parent %s\n",
1133                             sha1_to_hex(parent->object.sha1));
1134                 free(parents);
1135                 parents = next;
1136         }
1137
1138         /* Person/date information */
1139         if (!author)
1140                 author = git_author_info(IDENT_ERROR_ON_NO_NAME);
1141         strbuf_addf(&buffer, "author %s\n", author);
1142         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_ERROR_ON_NO_NAME));
1143         if (!encoding_is_utf8)
1144                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1145
1146         while (extra) {
1147                 add_extra_header(&buffer, extra);
1148                 extra = extra->next;
1149         }
1150         strbuf_addch(&buffer, '\n');
1151
1152         /* And add the comment */
1153         strbuf_addbuf(&buffer, msg);
1154
1155         /* And check the encoding */
1156         if (encoding_is_utf8 && !is_utf8(buffer.buf))
1157                 fprintf(stderr, commit_utf8_warn);
1158
1159         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1160                 return -1;
1161
1162         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1163         strbuf_release(&buffer);
1164         return result;
1165 }
1166
1167 struct commit *get_merge_parent(const char *name)
1168 {
1169         struct object *obj;
1170         struct commit *commit;
1171         unsigned char sha1[20];
1172         if (get_sha1(name, sha1))
1173                 return NULL;
1174         obj = parse_object(sha1);
1175         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1176         if (commit && !commit->util) {
1177                 struct merge_remote_desc *desc;
1178                 desc = xmalloc(sizeof(*desc));
1179                 desc->obj = obj;
1180                 desc->name = strdup(name);
1181                 commit->util = desc;
1182         }
1183         return commit;
1184 }