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 #include "mergesort.h"
  11
  12 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  13
  14 int save_commit_buffer = 1;
  15
  16 const char *commit_type = "commit";
  17
  18 static struct commit *check_commit(struct object *obj,
  19                                    const unsigned char *sha1,
  20                                    int quiet)
  21 {
  22         if (obj->type != OBJ_COMMIT) {
  23                 if (!quiet)
  24                         error("Object %s is a %s, not a commit",
  25                               sha1_to_hex(sha1), typename(obj->type));
  26                 return NULL;
  27         }
  28         return (struct commit *) obj;
  29 }
  30
  31 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  32                                               int quiet)
  33 {
  34         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  35
  36         if (!obj)
  37                 return NULL;
  38         return check_commit(obj, sha1, quiet);
  39 }
  40
  41 struct commit *lookup_commit_reference(const unsigned char *sha1)
  42 {
  43         return lookup_commit_reference_gently(sha1, 0);
  44 }
  45
  46 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  47 {
  48         struct commit *c = lookup_commit_reference(sha1);
  49         if (!c)
  50                 die(_("could not parse %s"), ref_name);
  51         if (hashcmp(sha1, c->object.sha1)) {
  52                 warning(_("%s %s is not a commit!"),
  53                         ref_name, sha1_to_hex(sha1));
  54         }
  55         return c;
  56 }
  57
  58 struct commit *lookup_commit(const unsigned char *sha1)
  59 {
  60         struct object *obj = lookup_object(sha1);
  61         if (!obj)
  62                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  63         if (!obj->type)
  64                 obj->type = OBJ_COMMIT;
  65         return check_commit(obj, sha1, 0);
  66 }
  67
  68 struct commit *lookup_commit_reference_by_name(const char *name)
  69 {
  70         unsigned char sha1[20];
  71         struct commit *commit;
  72
  73         if (get_sha1_committish(name, sha1))
  74                 return NULL;
  75         commit = lookup_commit_reference(sha1);
  76         if (!commit || parse_commit(commit))
  77                 return NULL;
  78         return commit;
  79 }
  80
  81 static unsigned long parse_commit_date(const char *buf, const char *tail)
  82 {
  83         const char *dateptr;
  84
  85         if (buf + 6 >= tail)
  86                 return 0;
  87         if (memcmp(buf, "author", 6))
  88                 return 0;
  89         while (buf < tail && *buf++ != '\n')
  90                 /* nada */;
  91         if (buf + 9 >= tail)
  92                 return 0;
  93         if (memcmp(buf, "committer", 9))
  94                 return 0;
  95         while (buf < tail && *buf++ != '>')
  96                 /* nada */;
  97         if (buf >= tail)
  98                 return 0;
  99         dateptr = buf;
 100         while (buf < tail && *buf++ != '\n')
 101                 /* nada */;
 102         if (buf >= tail)
 103                 return 0;
 104         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 105         return strtoul(dateptr, NULL, 10);
 106 }
 107
 108 static struct commit_graft **commit_graft;
 109 static int commit_graft_alloc, commit_graft_nr;
 110
 111 static int commit_graft_pos(const unsigned char *sha1)
 112 {
 113         int lo, hi;
 114         lo = 0;
 115         hi = commit_graft_nr;
 116         while (lo < hi) {
 117                 int mi = (lo + hi) / 2;
 118                 struct commit_graft *graft = commit_graft[mi];
 119                 int cmp = hashcmp(sha1, graft->sha1);
 120                 if (!cmp)
 121                         return mi;
 122                 if (cmp < 0)
 123                         hi = mi;
 124                 else
 125                         lo = mi + 1;
 126         }
 127         return -lo - 1;
 128 }
 129
 130 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 131 {
 132         int pos = commit_graft_pos(graft->sha1);
 133
 134         if (0 <= pos) {
 135                 if (ignore_dups)
 136                         free(graft);
 137                 else {
 138                         free(commit_graft[pos]);
 139                         commit_graft[pos] = graft;
 140                 }
 141                 return 1;
 142         }
 143         pos = -pos - 1;
 144         if (commit_graft_alloc <= ++commit_graft_nr) {
 145                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 146                 commit_graft = xrealloc(commit_graft,
 147                                         sizeof(*commit_graft) *
 148                                         commit_graft_alloc);
 149         }
 150         if (pos < commit_graft_nr)
 151                 memmove(commit_graft + pos + 1,
 152                         commit_graft + pos,
 153                         (commit_graft_nr - pos - 1) *
 154                         sizeof(*commit_graft));
 155         commit_graft[pos] = graft;
 156         return 0;
 157 }
 158
 159 struct commit_graft *read_graft_line(char *buf, int len)
 160 {
 161         /* The format is just "Commit Parent1 Parent2 ...\n" */
 162         int i;
 163         struct commit_graft *graft = NULL;
 164
 165         while (len && isspace(buf[len-1]))
 166                 buf[--len] = '\0';
 167         if (buf[0] == '#' || buf[0] == '\0')
 168                 return NULL;
 169         if ((len + 1) % 41)
 170                 goto bad_graft_data;
 171         i = (len + 1) / 41 - 1;
 172         graft = xmalloc(sizeof(*graft) + 20 * i);
 173         graft->nr_parent = i;
 174         if (get_sha1_hex(buf, graft->sha1))
 175                 goto bad_graft_data;
 176         for (i = 40; i < len; i += 41) {
 177                 if (buf[i] != ' ')
 178                         goto bad_graft_data;
 179                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 180                         goto bad_graft_data;
 181         }
 182         return graft;
 183
 184 bad_graft_data:
 185         error("bad graft data: %s", buf);
 186         free(graft);
 187         return NULL;
 188 }
 189
 190 static int read_graft_file(const char *graft_file)
 191 {
 192         FILE *fp = fopen(graft_file, "r");
 193         char buf[1024];
 194         if (!fp)
 195                 return -1;
 196         while (fgets(buf, sizeof(buf), fp)) {
 197                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 198                 int len = strlen(buf);
 199                 struct commit_graft *graft = read_graft_line(buf, len);
 200                 if (!graft)
 201                         continue;
 202                 if (register_commit_graft(graft, 1))
 203                         error("duplicate graft data: %s", buf);
 204         }
 205         fclose(fp);
 206         return 0;
 207 }
 208
 209 static void prepare_commit_graft(void)
 210 {
 211         static int commit_graft_prepared;
 212         char *graft_file;
 213
 214         if (commit_graft_prepared)
 215                 return;
 216         graft_file = get_graft_file();
 217         read_graft_file(graft_file);
 218         /* make sure shallows are read */
 219         is_repository_shallow();
 220         commit_graft_prepared = 1;
 221 }
 222
 223 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 224 {
 225         int pos;
 226         prepare_commit_graft();
 227         pos = commit_graft_pos(sha1);
 228         if (pos < 0)
 229                 return NULL;
 230         return commit_graft[pos];
 231 }
 232
 233 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 234 {
 235         int i, ret;
 236         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 237                 ret = fn(commit_graft[i], cb_data);
 238         return ret;
 239 }
 240
 241 int unregister_shallow(const unsigned char *sha1)
 242 {
 243         int pos = commit_graft_pos(sha1);
 244         if (pos < 0)
 245                 return -1;
 246         if (pos + 1 < commit_graft_nr)
 247                 memmove(commit_graft + pos, commit_graft + pos + 1,
 248                                 sizeof(struct commit_graft *)
 249                                 * (commit_graft_nr - pos - 1));
 250         commit_graft_nr--;
 251         return 0;
 252 }
 253
 254 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 255 {
 256         const char *tail = buffer;
 257         const char *bufptr = buffer;
 258         unsigned char parent[20];
 259         struct commit_list **pptr;
 260         struct commit_graft *graft;
 261
 262         if (item->object.parsed)
 263                 return 0;
 264         item->object.parsed = 1;
 265         tail += size;
 266         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 267                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 268         if (get_sha1_hex(bufptr + 5, parent) < 0)
 269                 return error("bad tree pointer in commit %s",
 270                              sha1_to_hex(item->object.sha1));
 271         item->tree = lookup_tree(parent);
 272         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 273         pptr = &item->parents;
 274
 275         graft = lookup_commit_graft(item->object.sha1);
 276         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 277                 struct commit *new_parent;
 278
 279                 if (tail <= bufptr + 48 ||
 280                     get_sha1_hex(bufptr + 7, parent) ||
 281                     bufptr[47] != '\n')
 282                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 283                 bufptr += 48;
 284                 /*
 285                  * The clone is shallow if nr_parent < 0, and we must
 286                  * not traverse its real parents even when we unhide them.
 287                  */
 288                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 289                         continue;
 290                 new_parent = lookup_commit(parent);
 291                 if (new_parent)
 292                         pptr = &commit_list_insert(new_parent, pptr)->next;
 293         }
 294         if (graft) {
 295                 int i;
 296                 struct commit *new_parent;
 297                 for (i = 0; i < graft->nr_parent; i++) {
 298                         new_parent = lookup_commit(graft->parent[i]);
 299                         if (!new_parent)
 300                                 continue;
 301                         pptr = &commit_list_insert(new_parent, pptr)->next;
 302                 }
 303         }
 304         item->date = parse_commit_date(bufptr, tail);
 305
 306         return 0;
 307 }
 308
 309 int parse_commit(struct commit *item)
 310 {
 311         enum object_type type;
 312         void *buffer;
 313         unsigned long size;
 314         int ret;
 315
 316         if (!item)
 317                 return -1;
 318         if (item->object.parsed)
 319                 return 0;
 320         buffer = read_sha1_file(item->object.sha1, &type, &size);
 321         if (!buffer)
 322                 return error("Could not read %s",
 323                              sha1_to_hex(item->object.sha1));
 324         if (type != OBJ_COMMIT) {
 325                 free(buffer);
 326                 return error("Object %s not a commit",
 327                              sha1_to_hex(item->object.sha1));
 328         }
 329         ret = parse_commit_buffer(item, buffer, size);
 330         if (save_commit_buffer && !ret) {
 331                 item->buffer = buffer;
 332                 return 0;
 333         }
 334         free(buffer);
 335         return ret;
 336 }
 337
 338 int find_commit_subject(const char *commit_buffer, const char **subject)
 339 {
 340         const char *eol;
 341         const char *p = commit_buffer;
 342
 343         while (*p && (*p != '\n' || p[1] != '\n'))
 344                 p++;
 345         if (*p) {
 346                 p += 2;
 347                 for (eol = p; *eol && *eol != '\n'; eol++)
 348                         ; /* do nothing */
 349         } else
 350                 eol = p;
 351
 352         *subject = p;
 353
 354         return eol - p;
 355 }
 356
 357 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 358 {
 359         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 360         new_list->item = item;
 361         new_list->next = *list_p;
 362         *list_p = new_list;
 363         return new_list;
 364 }
 365
 366 unsigned commit_list_count(const struct commit_list *l)
 367 {
 368         unsigned c = 0;
 369         for (; l; l = l->next )
 370                 c++;
 371         return c;
 372 }
 373
 374 void free_commit_list(struct commit_list *list)
 375 {
 376         while (list) {
 377                 struct commit_list *temp = list;
 378                 list = temp->next;
 379                 free(temp);
 380         }
 381 }
 382
 383 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 384 {
 385         struct commit_list **pp = list;
 386         struct commit_list *p;
 387         while ((p = *pp) != NULL) {
 388                 if (p->item->date < item->date) {
 389                         break;
 390                 }
 391                 pp = &p->next;
 392         }
 393         return commit_list_insert(item, pp);
 394 }
 395
 396 static int commit_list_compare_by_date(const void *a, const void *b)
 397 {
 398         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 399         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 400         if (a_date < b_date)
 401                 return 1;
 402         if (a_date > b_date)
 403                 return -1;
 404         return 0;
 405 }
 406
 407 static void *commit_list_get_next(const void *a)
 408 {
 409         return ((const struct commit_list *)a)->next;
 410 }
 411
 412 static void commit_list_set_next(void *a, void *next)
 413 {
 414         ((struct commit_list *)a)->next = next;
 415 }
 416
 417 void commit_list_sort_by_date(struct commit_list **list)
 418 {
 419         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 420                                 commit_list_compare_by_date);
 421 }
 422
 423 struct commit *pop_most_recent_commit(struct commit_list **list,
 424                                       unsigned int mark)
 425 {
 426         struct commit *ret = (*list)->item;
 427         struct commit_list *parents = ret->parents;
 428         struct commit_list *old = *list;
 429
 430         *list = (*list)->next;
 431         free(old);
 432
 433         while (parents) {
 434                 struct commit *commit = parents->item;
 435                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 436                         commit->object.flags |= mark;
 437                         commit_list_insert_by_date(commit, list);
 438                 }
 439                 parents = parents->next;
 440         }
 441         return ret;
 442 }
 443
 444 static void clear_commit_marks_1(struct commit_list **plist,
 445                                  struct commit *commit, unsigned int mark)
 446 {
 447         while (commit) {
 448                 struct commit_list *parents;
 449
 450                 if (!(mark & commit->object.flags))
 451                         return;
 452
 453                 commit->object.flags &= ~mark;
 454
 455                 parents = commit->parents;
 456                 if (!parents)
 457                         return;
 458
 459                 while ((parents = parents->next))
 460                         commit_list_insert(parents->item, plist);
 461
 462                 commit = commit->parents->item;
 463         }
 464 }
 465
 466 void clear_commit_marks(struct commit *commit, unsigned int mark)
 467 {
 468         struct commit_list *list = NULL;
 469         commit_list_insert(commit, &list);
 470         while (list)
 471                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 472 }
 473
 474 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 475 {
 476         struct object *object;
 477         struct commit *commit;
 478         unsigned int i;
 479
 480         for (i = 0; i < a->nr; i++) {
 481                 object = a->objects[i].item;
 482                 commit = lookup_commit_reference_gently(object->sha1, 1);
 483                 if (commit)
 484                         clear_commit_marks(commit, mark);
 485         }
 486 }
 487
 488 struct commit *pop_commit(struct commit_list **stack)
 489 {
 490         struct commit_list *top = *stack;
 491         struct commit *item = top ? top->item : NULL;
 492
 493         if (top) {
 494                 *stack = top->next;
 495                 free(top);
 496         }
 497         return item;
 498 }
 499
 500 /*
 501  * Performs an in-place topological sort on the list supplied.
 502  */
 503 void sort_in_topological_order(struct commit_list ** list, int lifo)
 504 {
 505         struct commit_list *next, *orig = *list;
 506         struct commit_list *work, **insert;
 507         struct commit_list **pptr;
 508
 509         if (!orig)
 510                 return;
 511         *list = NULL;
 512
 513         /* Mark them and clear the indegree */
 514         for (next = orig; next; next = next->next) {
 515                 struct commit *commit = next->item;
 516                 commit->indegree = 1;
 517         }
 518
 519         /* update the indegree */
 520         for (next = orig; next; next = next->next) {
 521                 struct commit_list * parents = next->item->parents;
 522                 while (parents) {
 523                         struct commit *parent = parents->item;
 524
 525                         if (parent->indegree)
 526                                 parent->indegree++;
 527                         parents = parents->next;
 528                 }
 529         }
 530
 531         /*
 532          * find the tips
 533          *
 534          * tips are nodes not reachable from any other node in the list
 535          *
 536          * the tips serve as a starting set for the work queue.
 537          */
 538         work = NULL;
 539         insert = &work;
 540         for (next = orig; next; next = next->next) {
 541                 struct commit *commit = next->item;
 542
 543                 if (commit->indegree == 1)
 544                         insert = &commit_list_insert(commit, insert)->next;
 545         }
 546
 547         /* process the list in topological order */
 548         if (!lifo)
 549                 commit_list_sort_by_date(&work);
 550
 551         pptr = list;
 552         *list = NULL;
 553         while (work) {
 554                 struct commit *commit;
 555                 struct commit_list *parents, *work_item;
 556
 557                 work_item = work;
 558                 work = work_item->next;
 559                 work_item->next = NULL;
 560
 561                 commit = work_item->item;
 562                 for (parents = commit->parents; parents ; parents = parents->next) {
 563                         struct commit *parent = parents->item;
 564
 565                         if (!parent->indegree)
 566                                 continue;
 567
 568                         /*
 569                          * parents are only enqueued for emission
 570                          * when all their children have been emitted thereby
 571                          * guaranteeing topological order.
 572                          */
 573                         if (--parent->indegree == 1) {
 574                                 if (!lifo)
 575                                         commit_list_insert_by_date(parent, &work);
 576                                 else
 577                                         commit_list_insert(parent, &work);
 578                         }
 579                 }
 580                 /*
 581                  * work_item is a commit all of whose children
 582                  * have already been emitted. we can emit it now.
 583                  */
 584                 commit->indegree = 0;
 585                 *pptr = work_item;
 586                 pptr = &work_item->next;
 587         }
 588 }
 589
 590 /* merge-base stuff */
 591
 592 /* bits #0..15 in revision.h */
 593 #define PARENT1         (1u<<16)
 594 #define PARENT2         (1u<<17)
 595 #define STALE           (1u<<18)
 596 #define RESULT          (1u<<19)
 597
 598 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 599
 600 static struct commit *interesting(struct commit_list *list)
 601 {
 602         while (list) {
 603                 struct commit *commit = list->item;
 604                 list = list->next;
 605                 if (commit->object.flags & STALE)
 606                         continue;
 607                 return commit;
 608         }
 609         return NULL;
 610 }
 611
 612 /* all input commits in one and twos[] must have been parsed! */
 613 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 614 {
 615         struct commit_list *list = NULL;
 616         struct commit_list *result = NULL;
 617         int i;
 618
 619         one->object.flags |= PARENT1;
 620         commit_list_insert_by_date(one, &list);
 621         if (!n)
 622                 return list;
 623         for (i = 0; i < n; i++) {
 624                 twos[i]->object.flags |= PARENT2;
 625                 commit_list_insert_by_date(twos[i], &list);
 626         }
 627
 628         while (interesting(list)) {
 629                 struct commit *commit;
 630                 struct commit_list *parents;
 631                 struct commit_list *next;
 632                 int flags;
 633
 634                 commit = list->item;
 635                 next = list->next;
 636                 free(list);
 637                 list = next;
 638
 639                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 640                 if (flags == (PARENT1 | PARENT2)) {
 641                         if (!(commit->object.flags & RESULT)) {
 642                                 commit->object.flags |= RESULT;
 643                                 commit_list_insert_by_date(commit, &result);
 644                         }
 645                         /* Mark parents of a found merge stale */
 646                         flags |= STALE;
 647                 }
 648                 parents = commit->parents;
 649                 while (parents) {
 650                         struct commit *p = parents->item;
 651                         parents = parents->next;
 652                         if ((p->object.flags & flags) == flags)
 653                                 continue;
 654                         if (parse_commit(p))
 655                                 return NULL;
 656                         p->object.flags |= flags;
 657                         commit_list_insert_by_date(p, &list);
 658                 }
 659         }
 660
 661         free_commit_list(list);
 662         return result;
 663 }
 664
 665 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 666 {
 667         struct commit_list *list = NULL;
 668         struct commit_list *result = NULL;
 669         int i;
 670
 671         for (i = 0; i < n; i++) {
 672                 if (one == twos[i])
 673                         /*
 674                          * We do not mark this even with RESULT so we do not
 675                          * have to clean it up.
 676                          */
 677                         return commit_list_insert(one, &result);
 678         }
 679
 680         if (parse_commit(one))
 681                 return NULL;
 682         for (i = 0; i < n; i++) {
 683                 if (parse_commit(twos[i]))
 684                         return NULL;
 685         }
 686
 687         list = paint_down_to_common(one, n, twos);
 688
 689         while (list) {
 690                 struct commit_list *next = list->next;
 691                 if (!(list->item->object.flags & STALE))
 692                         commit_list_insert_by_date(list->item, &result);
 693                 free(list);
 694                 list = next;
 695         }
 696         return result;
 697 }
 698
 699 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 700 {
 701         struct commit_list *i, *j, *k, *ret = NULL;
 702         struct commit_list **pptr = &ret;
 703
 704         for (i = in; i; i = i->next) {
 705                 if (!ret)
 706                         pptr = &commit_list_insert(i->item, pptr)->next;
 707                 else {
 708                         struct commit_list *new = NULL, *end = NULL;
 709
 710                         for (j = ret; j; j = j->next) {
 711                                 struct commit_list *bases;
 712                                 bases = get_merge_bases(i->item, j->item, 1);
 713                                 if (!new)
 714                                         new = bases;
 715                                 else
 716                                         end->next = bases;
 717                                 for (k = bases; k; k = k->next)
 718                                         end = k;
 719                         }
 720                         ret = new;
 721                 }
 722         }
 723         return ret;
 724 }
 725
 726 static int remove_redundant(struct commit **array, int cnt)
 727 {
 728         /*
 729          * Some commit in the array may be an ancestor of
 730          * another commit.  Move such commit to the end of
 731          * the array, and return the number of commits that
 732          * are independent from each other.
 733          */
 734         struct commit **work;
 735         unsigned char *redundant;
 736         int *filled_index;
 737         int i, j, filled;
 738
 739         work = xcalloc(cnt, sizeof(*work));
 740         redundant = xcalloc(cnt, 1);
 741         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 742
 743         for (i = 0; i < cnt; i++)
 744                 parse_commit(array[i]);
 745         for (i = 0; i < cnt; i++) {
 746                 struct commit_list *common;
 747
 748                 if (redundant[i])
 749                         continue;
 750                 for (j = filled = 0; j < cnt; j++) {
 751                         if (i == j || redundant[j])
 752                                 continue;
 753                         filled_index[filled] = j;
 754                         work[filled++] = array[j];
 755                 }
 756                 common = paint_down_to_common(array[i], filled, work);
 757                 if (array[i]->object.flags & PARENT2)
 758                         redundant[i] = 1;
 759                 for (j = 0; j < filled; j++)
 760                         if (work[j]->object.flags & PARENT1)
 761                                 redundant[filled_index[j]] = 1;
 762                 clear_commit_marks(array[i], all_flags);
 763                 for (j = 0; j < filled; j++)
 764                         clear_commit_marks(work[j], all_flags);
 765                 free_commit_list(common);
 766         }
 767
 768         /* Now collect the result */
 769         memcpy(work, array, sizeof(*array) * cnt);
 770         for (i = filled = 0; i < cnt; i++)
 771                 if (!redundant[i])
 772                         array[filled++] = work[i];
 773         for (j = filled, i = 0; i < cnt; i++)
 774                 if (redundant[i])
 775                         array[j++] = work[i];
 776         free(work);
 777         free(redundant);
 778         free(filled_index);
 779         return filled;
 780 }
 781
 782 struct commit_list *get_merge_bases_many(struct commit *one,
 783                                          int n,
 784                                          struct commit **twos,
 785                                          int cleanup)
 786 {
 787         struct commit_list *list;
 788         struct commit **rslt;
 789         struct commit_list *result;
 790         int cnt, i;
 791
 792         result = merge_bases_many(one, n, twos);
 793         for (i = 0; i < n; i++) {
 794                 if (one == twos[i])
 795                         return result;
 796         }
 797         if (!result || !result->next) {
 798                 if (cleanup) {
 799                         clear_commit_marks(one, all_flags);
 800                         for (i = 0; i < n; i++)
 801                                 clear_commit_marks(twos[i], all_flags);
 802                 }
 803                 return result;
 804         }
 805
 806         /* There are more than one */
 807         cnt = 0;
 808         list = result;
 809         while (list) {
 810                 list = list->next;
 811                 cnt++;
 812         }
 813         rslt = xcalloc(cnt, sizeof(*rslt));
 814         for (list = result, i = 0; list; list = list->next)
 815                 rslt[i++] = list->item;
 816         free_commit_list(result);
 817
 818         clear_commit_marks(one, all_flags);
 819         for (i = 0; i < n; i++)
 820                 clear_commit_marks(twos[i], all_flags);
 821
 822         cnt = remove_redundant(rslt, cnt);
 823         result = NULL;
 824         for (i = 0; i < cnt; i++)
 825                 commit_list_insert_by_date(rslt[i], &result);
 826         free(rslt);
 827         return result;
 828 }
 829
 830 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 831                                     int cleanup)
 832 {
 833         return get_merge_bases_many(one, 1, &two, cleanup);
 834 }
 835
 836 /*
 837  * Is "commit" a decendant of one of the elements on the "with_commit" list?
 838  */
 839 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 840 {
 841         if (!with_commit)
 842                 return 1;
 843         while (with_commit) {
 844                 struct commit *other;
 845
 846                 other = with_commit->item;
 847                 with_commit = with_commit->next;
 848                 if (in_merge_bases(other, commit))
 849                         return 1;
 850         }
 851         return 0;
 852 }
 853
 854 /*
 855  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 856  */
 857 int in_merge_bases(struct commit *commit, struct commit *reference)
 858 {
 859         struct commit_list *bases;
 860         int ret = 0;
 861
 862         if (parse_commit(commit) || parse_commit(reference))
 863                 return ret;
 864
 865         bases = paint_down_to_common(commit, 1, &reference);
 866         if (commit->object.flags & PARENT2)
 867                 ret = 1;
 868         clear_commit_marks(commit, all_flags);
 869         clear_commit_marks(reference, all_flags);
 870         free_commit_list(bases);
 871         return ret;
 872 }
 873
 874 struct commit_list *reduce_heads(struct commit_list *heads)
 875 {
 876         struct commit_list *p;
 877         struct commit_list *result = NULL, **tail = &result;
 878         struct commit **array;
 879         int num_head, i;
 880
 881         if (!heads)
 882                 return NULL;
 883
 884         /* Uniquify */
 885         for (p = heads; p; p = p->next)
 886                 p->item->object.flags &= ~STALE;
 887         for (p = heads, num_head = 0; p; p = p->next) {
 888                 if (p->item->object.flags & STALE)
 889                         continue;
 890                 p->item->object.flags |= STALE;
 891                 num_head++;
 892         }
 893         array = xcalloc(sizeof(*array), num_head);
 894         for (p = heads, i = 0; p; p = p->next) {
 895                 if (p->item->object.flags & STALE) {
 896                         array[i++] = p->item;
 897                         p->item->object.flags &= ~STALE;
 898                 }
 899         }
 900         num_head = remove_redundant(array, num_head);
 901         for (i = 0; i < num_head; i++)
 902                 tail = &commit_list_insert(array[i], tail)->next;
 903         return result;
 904 }
 905
 906 static const char gpg_sig_header[] = "gpgsig";
 907 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 908
 909 static int do_sign_commit(struct strbuf *buf, const char *keyid)
 910 {
 911         struct strbuf sig = STRBUF_INIT;
 912         int inspos, copypos;
 913
 914         /* find the end of the header */
 915         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
 916
 917         if (!keyid || !*keyid)
 918                 keyid = get_signing_key();
 919         if (sign_buffer(buf, &sig, keyid)) {
 920                 strbuf_release(&sig);
 921                 return -1;
 922         }
 923
 924         for (copypos = 0; sig.buf[copypos]; ) {
 925                 const char *bol = sig.buf + copypos;
 926                 const char *eol = strchrnul(bol, '\n');
 927                 int len = (eol - bol) + !!*eol;
 928
 929                 if (!copypos) {
 930                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 931                         inspos += gpg_sig_header_len;
 932                 }
 933                 strbuf_insert(buf, inspos++, " ", 1);
 934                 strbuf_insert(buf, inspos, bol, len);
 935                 inspos += len;
 936                 copypos += len;
 937         }
 938         strbuf_release(&sig);
 939         return 0;
 940 }
 941
 942 int parse_signed_commit(const unsigned char *sha1,
 943                         struct strbuf *payload, struct strbuf *signature)
 944 {
 945         unsigned long size;
 946         enum object_type type;
 947         char *buffer = read_sha1_file(sha1, &type, &size);
 948         int in_signature, saw_signature = -1;
 949         char *line, *tail;
 950
 951         if (!buffer || type != OBJ_COMMIT)
 952                 goto cleanup;
 953
 954         line = buffer;
 955         tail = buffer + size;
 956         in_signature = 0;
 957         saw_signature = 0;
 958         while (line < tail) {
 959                 const char *sig = NULL;
 960                 char *next = memchr(line, '\n', tail - line);
 961
 962                 next = next ? next + 1 : tail;
 963                 if (in_signature && line[0] == ' ')
 964                         sig = line + 1;
 965                 else if (!prefixcmp(line, gpg_sig_header) &&
 966                          line[gpg_sig_header_len] == ' ')
 967                         sig = line + gpg_sig_header_len + 1;
 968                 if (sig) {
 969                         strbuf_add(signature, sig, next - sig);
 970                         saw_signature = 1;
 971                         in_signature = 1;
 972                 } else {
 973                         if (*line == '\n')
 974                                 /* dump the whole remainder of the buffer */
 975                                 next = tail;
 976                         strbuf_add(payload, line, next - line);
 977                         in_signature = 0;
 978                 }
 979                 line = next;
 980         }
 981  cleanup:
 982         free(buffer);
 983         return saw_signature;
 984 }
 985
 986 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 987 {
 988         struct merge_remote_desc *desc;
 989         struct commit_extra_header *mergetag;
 990         char *buf;
 991         unsigned long size, len;
 992         enum object_type type;
 993
 994         desc = merge_remote_util(parent);
 995         if (!desc || !desc->obj)
 996                 return;
 997         buf = read_sha1_file(desc->obj->sha1, &type, &size);
 998         if (!buf || type != OBJ_TAG)
 999                 goto free_return;
1000         len = parse_signature(buf, size);
1001         if (size == len)
1002                 goto free_return;
1003         /*
1004          * We could verify this signature and either omit the tag when
1005          * it does not validate, but the integrator may not have the
1006          * public key of the signer of the tag he is merging, while a
1007          * later auditor may have it while auditing, so let's not run
1008          * verify-signed-buffer here for now...
1009          *
1010          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1011          *      warn("warning: signed tag unverified.");
1012          */
1013         mergetag = xcalloc(1, sizeof(*mergetag));
1014         mergetag->key = xstrdup("mergetag");
1015         mergetag->value = buf;
1016         mergetag->len = size;
1017
1018         **tail = mergetag;
1019         *tail = &mergetag->next;
1020         return;
1021
1022 free_return:
1023         free(buf);
1024 }
1025
1026 void append_merge_tag_headers(struct commit_list *parents,
1027                               struct commit_extra_header ***tail)
1028 {
1029         while (parents) {
1030                 struct commit *parent = parents->item;
1031                 handle_signed_tag(parent, tail);
1032                 parents = parents->next;
1033         }
1034 }
1035
1036 static void add_extra_header(struct strbuf *buffer,
1037                              struct commit_extra_header *extra)
1038 {
1039         strbuf_addstr(buffer, extra->key);
1040         if (extra->len)
1041                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1042         else
1043                 strbuf_addch(buffer, '\n');
1044 }
1045
1046 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1047                                                       const char **exclude)
1048 {
1049         struct commit_extra_header *extra = NULL;
1050         unsigned long size;
1051         enum object_type type;
1052         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1053         if (buffer && type == OBJ_COMMIT)
1054                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1055         free(buffer);
1056         return extra;
1057 }
1058
1059 static inline int standard_header_field(const char *field, size_t len)
1060 {
1061         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1062                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1063                 (len == 6 && !memcmp(field, "author ", 7)) ||
1064                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1065                 (len == 8 && !memcmp(field, "encoding ", 9)));
1066 }
1067
1068 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1069 {
1070         if (!exclude)
1071                 return 0;
1072
1073         while (*exclude) {
1074                 size_t xlen = strlen(*exclude);
1075                 if (len == xlen &&
1076                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1077                         return 1;
1078                 exclude++;
1079         }
1080         return 0;
1081 }
1082
1083 static struct commit_extra_header *read_commit_extra_header_lines(
1084         const char *buffer, size_t size,
1085         const char **exclude)
1086 {
1087         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1088         const char *line, *next, *eof, *eob;
1089         struct strbuf buf = STRBUF_INIT;
1090
1091         for (line = buffer, eob = line + size;
1092              line < eob && *line != '\n';
1093              line = next) {
1094                 next = memchr(line, '\n', eob - line);
1095                 next = next ? next + 1 : eob;
1096                 if (*line == ' ') {
1097                         /* continuation */
1098                         if (it)
1099                                 strbuf_add(&buf, line + 1, next - (line + 1));
1100                         continue;
1101                 }
1102                 if (it)
1103                         it->value = strbuf_detach(&buf, &it->len);
1104                 strbuf_reset(&buf);
1105                 it = NULL;
1106
1107                 eof = strchr(line, ' ');
1108                 if (next <= eof)
1109                         eof = next;
1110
1111                 if (standard_header_field(line, eof - line) ||
1112                     excluded_header_field(line, eof - line, exclude))
1113                         continue;
1114
1115                 it = xcalloc(1, sizeof(*it));
1116                 it->key = xmemdupz(line, eof-line);
1117                 *tail = it;
1118                 tail = &it->next;
1119                 if (eof + 1 < next)
1120                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1121         }
1122         if (it)
1123                 it->value = strbuf_detach(&buf, &it->len);
1124         return extra;
1125 }
1126
1127 void free_commit_extra_headers(struct commit_extra_header *extra)
1128 {
1129         while (extra) {
1130                 struct commit_extra_header *next = extra->next;
1131                 free(extra->key);
1132                 free(extra->value);
1133                 free(extra);
1134                 extra = next;
1135         }
1136 }
1137
1138 int commit_tree(const struct strbuf *msg, unsigned char *tree,
1139                 struct commit_list *parents, unsigned char *ret,
1140                 const char *author, const char *sign_commit)
1141 {
1142         struct commit_extra_header *extra = NULL, **tail = &extra;
1143         int result;
1144
1145         append_merge_tag_headers(parents, &tail);
1146         result = commit_tree_extended(msg, tree, parents, ret,
1147                                       author, sign_commit, extra);
1148         free_commit_extra_headers(extra);
1149         return result;
1150 }
1151
1152 static int find_invalid_utf8(const char *buf, int len)
1153 {
1154         int offset = 0;
1155
1156         while (len) {
1157                 unsigned char c = *buf++;
1158                 int bytes, bad_offset;
1159
1160                 len--;
1161                 offset++;
1162
1163                 /* Simple US-ASCII? No worries. */
1164                 if (c < 0x80)
1165                         continue;
1166
1167                 bad_offset = offset-1;
1168
1169                 /*
1170                  * Count how many more high bits set: that's how
1171                  * many more bytes this sequence should have.
1172                  */
1173                 bytes = 0;
1174                 while (c & 0x40) {
1175                         c <<= 1;
1176                         bytes++;
1177                 }
1178
1179                 /* Must be between 1 and 5 more bytes */
1180                 if (bytes < 1 || bytes > 5)
1181                         return bad_offset;
1182
1183                 /* Do we *have* that many bytes? */
1184                 if (len < bytes)
1185                         return bad_offset;
1186
1187                 offset += bytes;
1188                 len -= bytes;
1189
1190                 /* And verify that they are good continuation bytes */
1191                 do {
1192                         if ((*buf++ & 0xc0) != 0x80)
1193                                 return bad_offset;
1194                 } while (--bytes);
1195
1196                 /* We could/should check the value and length here too */
1197         }
1198         return -1;
1199 }
1200
1201 /*
1202  * This verifies that the buffer is in proper utf8 format.
1203  *
1204  * If it isn't, it assumes any non-utf8 characters are Latin1,
1205  * and does the conversion.
1206  *
1207  * Fixme: we should probably also disallow overlong forms and
1208  * invalid characters. But we don't do that currently.
1209  */
1210 static int verify_utf8(struct strbuf *buf)
1211 {
1212         int ok = 1;
1213         long pos = 0;
1214
1215         for (;;) {
1216                 int bad;
1217                 unsigned char c;
1218                 unsigned char replace[2];
1219
1220                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1221                 if (bad < 0)
1222                         return ok;
1223                 pos += bad;
1224                 ok = 0;
1225                 c = buf->buf[pos];
1226                 strbuf_remove(buf, pos, 1);
1227
1228                 /* We know 'c' must be in the range 128-255 */
1229                 replace[0] = 0xc0 + (c >> 6);
1230                 replace[1] = 0x80 + (c & 0x3f);
1231                 strbuf_insert(buf, pos, replace, 2);
1232                 pos += 2;
1233         }
1234 }
1235
1236 static const char commit_utf8_warn[] =
1237 "Warning: commit message did not conform to UTF-8.\n"
1238 "You may want to amend it after fixing the message, or set the config\n"
1239 "variable i18n.commitencoding to the encoding your project uses.\n";
1240
1241 int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1242                          struct commit_list *parents, unsigned char *ret,
1243                          const char *author, const char *sign_commit,
1244                          struct commit_extra_header *extra)
1245 {
1246         int result;
1247         int encoding_is_utf8;
1248         struct strbuf buffer;
1249
1250         assert_sha1_type(tree, OBJ_TREE);
1251
1252         if (memchr(msg->buf, '\0', msg->len))
1253                 return error("a NUL byte in commit log message not allowed.");
1254
1255         /* Not having i18n.commitencoding is the same as having utf-8 */
1256         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1257
1258         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1259         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1260
1261         /*
1262          * NOTE! This ordering means that the same exact tree merged with a
1263          * different order of parents will be a _different_ changeset even
1264          * if everything else stays the same.
1265          */
1266         while (parents) {
1267                 struct commit_list *next = parents->next;
1268                 struct commit *parent = parents->item;
1269
1270                 strbuf_addf(&buffer, "parent %s\n",
1271                             sha1_to_hex(parent->object.sha1));
1272                 free(parents);
1273                 parents = next;
1274         }
1275
1276         /* Person/date information */
1277         if (!author)
1278                 author = git_author_info(IDENT_STRICT);
1279         strbuf_addf(&buffer, "author %s\n", author);
1280         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1281         if (!encoding_is_utf8)
1282                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1283
1284         while (extra) {
1285                 add_extra_header(&buffer, extra);
1286                 extra = extra->next;
1287         }
1288         strbuf_addch(&buffer, '\n');
1289
1290         /* And add the comment */
1291         strbuf_addbuf(&buffer, msg);
1292
1293         /* And check the encoding */
1294         if (encoding_is_utf8 && !verify_utf8(&buffer))
1295                 fprintf(stderr, commit_utf8_warn);
1296
1297         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1298                 return -1;
1299
1300         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1301         strbuf_release(&buffer);
1302         return result;
1303 }
1304
1305 struct commit *get_merge_parent(const char *name)
1306 {
1307         struct object *obj;
1308         struct commit *commit;
1309         unsigned char sha1[20];
1310         if (get_sha1(name, sha1))
1311                 return NULL;
1312         obj = parse_object(sha1);
1313         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1314         if (commit && !commit->util) {
1315                 struct merge_remote_desc *desc;
1316                 desc = xmalloc(sizeof(*desc));
1317                 desc->obj = obj;
1318                 desc->name = strdup(name);
1319                 commit->util = desc;
1320         }
1321         return commit;
1322 }
1323
1324 /*
1325  * Append a commit to the end of the commit_list.
1326  *
1327  * next starts by pointing to the variable that holds the head of an
1328  * empty commit_list, and is updated to point to the "next" field of
1329  * the last item on the list as new commits are appended.
1330  *
1331  * Usage example:
1332  *
1333  *     struct commit_list *list;
1334  *     struct commit_list **next = &list;
1335  *
1336  *     next = commit_list_append(c1, next);
1337  *     next = commit_list_append(c2, next);
1338  *     assert(commit_list_count(list) == 2);
1339  *     return list;
1340  */
1341 struct commit_list **commit_list_append(struct commit *commit,
1342                                         struct commit_list **next)
1343 {
1344         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1345         new->item = commit;
1346         *next = new;
1347         new->next = NULL;
1348         return &new->next;
1349 }
1350
1351 void print_commit_list(struct commit_list *list,
1352                        const char *format_cur,
1353                        const char *format_last)
1354 {
1355         for ( ; list; list = list->next) {
1356                 const char *format = list->next ? format_cur : format_last;
1357                 printf(format, sha1_to_hex(list->item->object.sha1));
1358         }
1359 }