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 #include "commit-slab.h"
  12 #include "prio-queue.h"
  13
  14 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  15
  16 int save_commit_buffer = 1;
  17
  18 const char *commit_type = "commit";
  19 static int commit_count;
  20
  21 static struct commit *check_commit(struct object *obj,
  22                                    const unsigned char *sha1,
  23                                    int quiet)
  24 {
  25         if (obj->type != OBJ_COMMIT) {
  26                 if (!quiet)
  27                         error("Object %s is a %s, not a commit",
  28                               sha1_to_hex(sha1), typename(obj->type));
  29                 return NULL;
  30         }
  31         return (struct commit *) obj;
  32 }
  33
  34 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  35                                               int quiet)
  36 {
  37         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  38
  39         if (!obj)
  40                 return NULL;
  41         return check_commit(obj, sha1, quiet);
  42 }
  43
  44 struct commit *lookup_commit_reference(const unsigned char *sha1)
  45 {
  46         return lookup_commit_reference_gently(sha1, 0);
  47 }
  48
  49 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  50 {
  51         struct commit *c = lookup_commit_reference(sha1);
  52         if (!c)
  53                 die(_("could not parse %s"), ref_name);
  54         if (hashcmp(sha1, c->object.sha1)) {
  55                 warning(_("%s %s is not a commit!"),
  56                         ref_name, sha1_to_hex(sha1));
  57         }
  58         return c;
  59 }
  60
  61 struct commit *lookup_commit(const unsigned char *sha1)
  62 {
  63         struct object *obj = lookup_object(sha1);
  64         if (!obj) {
  65                 struct commit *c = alloc_commit_node();
  66                 c->index = commit_count++;
  67                 return create_object(sha1, OBJ_COMMIT, c);
  68         }
  69         if (!obj->type)
  70                 obj->type = OBJ_COMMIT;
  71         return check_commit(obj, sha1, 0);
  72 }
  73
  74 struct commit *lookup_commit_reference_by_name(const char *name)
  75 {
  76         unsigned char sha1[20];
  77         struct commit *commit;
  78
  79         if (get_sha1_committish(name, sha1))
  80                 return NULL;
  81         commit = lookup_commit_reference(sha1);
  82         if (!commit || parse_commit(commit))
  83                 return NULL;
  84         return commit;
  85 }
  86
  87 static unsigned long parse_commit_date(const char *buf, const char *tail)
  88 {
  89         const char *dateptr;
  90
  91         if (buf + 6 >= tail)
  92                 return 0;
  93         if (memcmp(buf, "author", 6))
  94                 return 0;
  95         while (buf < tail && *buf++ != '\n')
  96                 /* nada */;
  97         if (buf + 9 >= tail)
  98                 return 0;
  99         if (memcmp(buf, "committer", 9))
 100                 return 0;
 101         while (buf < tail && *buf++ != '>')
 102                 /* nada */;
 103         if (buf >= tail)
 104                 return 0;
 105         dateptr = buf;
 106         while (buf < tail && *buf++ != '\n')
 107                 /* nada */;
 108         if (buf >= tail)
 109                 return 0;
 110         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 111         return strtoul(dateptr, NULL, 10);
 112 }
 113
 114 static struct commit_graft **commit_graft;
 115 static int commit_graft_alloc, commit_graft_nr;
 116
 117 static int commit_graft_pos(const unsigned char *sha1)
 118 {
 119         int lo, hi;
 120         lo = 0;
 121         hi = commit_graft_nr;
 122         while (lo < hi) {
 123                 int mi = (lo + hi) / 2;
 124                 struct commit_graft *graft = commit_graft[mi];
 125                 int cmp = hashcmp(sha1, graft->sha1);
 126                 if (!cmp)
 127                         return mi;
 128                 if (cmp < 0)
 129                         hi = mi;
 130                 else
 131                         lo = mi + 1;
 132         }
 133         return -lo - 1;
 134 }
 135
 136 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 137 {
 138         int pos = commit_graft_pos(graft->sha1);
 139
 140         if (0 <= pos) {
 141                 if (ignore_dups)
 142                         free(graft);
 143                 else {
 144                         free(commit_graft[pos]);
 145                         commit_graft[pos] = graft;
 146                 }
 147                 return 1;
 148         }
 149         pos = -pos - 1;
 150         if (commit_graft_alloc <= ++commit_graft_nr) {
 151                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 152                 commit_graft = xrealloc(commit_graft,
 153                                         sizeof(*commit_graft) *
 154                                         commit_graft_alloc);
 155         }
 156         if (pos < commit_graft_nr)
 157                 memmove(commit_graft + pos + 1,
 158                         commit_graft + pos,
 159                         (commit_graft_nr - pos - 1) *
 160                         sizeof(*commit_graft));
 161         commit_graft[pos] = graft;
 162         return 0;
 163 }
 164
 165 struct commit_graft *read_graft_line(char *buf, int len)
 166 {
 167         /* The format is just "Commit Parent1 Parent2 ...\n" */
 168         int i;
 169         struct commit_graft *graft = NULL;
 170
 171         while (len && isspace(buf[len-1]))
 172                 buf[--len] = '\0';
 173         if (buf[0] == '#' || buf[0] == '\0')
 174                 return NULL;
 175         if ((len + 1) % 41)
 176                 goto bad_graft_data;
 177         i = (len + 1) / 41 - 1;
 178         graft = xmalloc(sizeof(*graft) + 20 * i);
 179         graft->nr_parent = i;
 180         if (get_sha1_hex(buf, graft->sha1))
 181                 goto bad_graft_data;
 182         for (i = 40; i < len; i += 41) {
 183                 if (buf[i] != ' ')
 184                         goto bad_graft_data;
 185                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 186                         goto bad_graft_data;
 187         }
 188         return graft;
 189
 190 bad_graft_data:
 191         error("bad graft data: %s", buf);
 192         free(graft);
 193         return NULL;
 194 }
 195
 196 static int read_graft_file(const char *graft_file)
 197 {
 198         FILE *fp = fopen(graft_file, "r");
 199         char buf[1024];
 200         if (!fp)
 201                 return -1;
 202         while (fgets(buf, sizeof(buf), fp)) {
 203                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 204                 int len = strlen(buf);
 205                 struct commit_graft *graft = read_graft_line(buf, len);
 206                 if (!graft)
 207                         continue;
 208                 if (register_commit_graft(graft, 1))
 209                         error("duplicate graft data: %s", buf);
 210         }
 211         fclose(fp);
 212         return 0;
 213 }
 214
 215 static void prepare_commit_graft(void)
 216 {
 217         static int commit_graft_prepared;
 218         char *graft_file;
 219
 220         if (commit_graft_prepared)
 221                 return;
 222         graft_file = get_graft_file();
 223         read_graft_file(graft_file);
 224         /* make sure shallows are read */
 225         is_repository_shallow();
 226         commit_graft_prepared = 1;
 227 }
 228
 229 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 230 {
 231         int pos;
 232         prepare_commit_graft();
 233         pos = commit_graft_pos(sha1);
 234         if (pos < 0)
 235                 return NULL;
 236         return commit_graft[pos];
 237 }
 238
 239 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 240 {
 241         int i, ret;
 242         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 243                 ret = fn(commit_graft[i], cb_data);
 244         return ret;
 245 }
 246
 247 int unregister_shallow(const unsigned char *sha1)
 248 {
 249         int pos = commit_graft_pos(sha1);
 250         if (pos < 0)
 251                 return -1;
 252         if (pos + 1 < commit_graft_nr)
 253                 memmove(commit_graft + pos, commit_graft + pos + 1,
 254                                 sizeof(struct commit_graft *)
 255                                 * (commit_graft_nr - pos - 1));
 256         commit_graft_nr--;
 257         return 0;
 258 }
 259
 260 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 261 {
 262         const char *tail = buffer;
 263         const char *bufptr = buffer;
 264         unsigned char parent[20];
 265         struct commit_list **pptr;
 266         struct commit_graft *graft;
 267
 268         if (item->object.parsed)
 269                 return 0;
 270         item->object.parsed = 1;
 271         tail += size;
 272         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 273                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 274         if (get_sha1_hex(bufptr + 5, parent) < 0)
 275                 return error("bad tree pointer in commit %s",
 276                              sha1_to_hex(item->object.sha1));
 277         item->tree = lookup_tree(parent);
 278         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 279         pptr = &item->parents;
 280
 281         graft = lookup_commit_graft(item->object.sha1);
 282         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 283                 struct commit *new_parent;
 284
 285                 if (tail <= bufptr + 48 ||
 286                     get_sha1_hex(bufptr + 7, parent) ||
 287                     bufptr[47] != '\n')
 288                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 289                 bufptr += 48;
 290                 /*
 291                  * The clone is shallow if nr_parent < 0, and we must
 292                  * not traverse its real parents even when we unhide them.
 293                  */
 294                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 295                         continue;
 296                 new_parent = lookup_commit(parent);
 297                 if (new_parent)
 298                         pptr = &commit_list_insert(new_parent, pptr)->next;
 299         }
 300         if (graft) {
 301                 int i;
 302                 struct commit *new_parent;
 303                 for (i = 0; i < graft->nr_parent; i++) {
 304                         new_parent = lookup_commit(graft->parent[i]);
 305                         if (!new_parent)
 306                                 continue;
 307                         pptr = &commit_list_insert(new_parent, pptr)->next;
 308                 }
 309         }
 310         item->date = parse_commit_date(bufptr, tail);
 311
 312         return 0;
 313 }
 314
 315 int parse_commit(struct commit *item)
 316 {
 317         enum object_type type;
 318         void *buffer;
 319         unsigned long size;
 320         int ret;
 321
 322         if (!item)
 323                 return -1;
 324         if (item->object.parsed)
 325                 return 0;
 326         buffer = read_sha1_file(item->object.sha1, &type, &size);
 327         if (!buffer)
 328                 return error("Could not read %s",
 329                              sha1_to_hex(item->object.sha1));
 330         if (type != OBJ_COMMIT) {
 331                 free(buffer);
 332                 return error("Object %s not a commit",
 333                              sha1_to_hex(item->object.sha1));
 334         }
 335         ret = parse_commit_buffer(item, buffer, size);
 336         if (save_commit_buffer && !ret) {
 337                 item->buffer = buffer;
 338                 return 0;
 339         }
 340         free(buffer);
 341         return ret;
 342 }
 343
 344 int find_commit_subject(const char *commit_buffer, const char **subject)
 345 {
 346         const char *eol;
 347         const char *p = commit_buffer;
 348
 349         while (*p && (*p != '\n' || p[1] != '\n'))
 350                 p++;
 351         if (*p) {
 352                 p += 2;
 353                 for (eol = p; *eol && *eol != '\n'; eol++)
 354                         ; /* do nothing */
 355         } else
 356                 eol = p;
 357
 358         *subject = p;
 359
 360         return eol - p;
 361 }
 362
 363 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 364 {
 365         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 366         new_list->item = item;
 367         new_list->next = *list_p;
 368         *list_p = new_list;
 369         return new_list;
 370 }
 371
 372 unsigned commit_list_count(const struct commit_list *l)
 373 {
 374         unsigned c = 0;
 375         for (; l; l = l->next )
 376                 c++;
 377         return c;
 378 }
 379
 380 struct commit_list *copy_commit_list(struct commit_list *list)
 381 {
 382         struct commit_list *head = NULL;
 383         struct commit_list **pp = &head;
 384         while (list) {
 385                 struct commit_list *new;
 386                 new = xmalloc(sizeof(struct commit_list));
 387                 new->item = list->item;
 388                 new->next = NULL;
 389                 *pp = new;
 390                 pp = &new->next;
 391                 list = list->next;
 392         }
 393         return head;
 394 }
 395
 396 void free_commit_list(struct commit_list *list)
 397 {
 398         while (list) {
 399                 struct commit_list *temp = list;
 400                 list = temp->next;
 401                 free(temp);
 402         }
 403 }
 404
 405 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 406 {
 407         struct commit_list **pp = list;
 408         struct commit_list *p;
 409         while ((p = *pp) != NULL) {
 410                 if (p->item->date < item->date) {
 411                         break;
 412                 }
 413                 pp = &p->next;
 414         }
 415         return commit_list_insert(item, pp);
 416 }
 417
 418 static int commit_list_compare_by_date(const void *a, const void *b)
 419 {
 420         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 421         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 422         if (a_date < b_date)
 423                 return 1;
 424         if (a_date > b_date)
 425                 return -1;
 426         return 0;
 427 }
 428
 429 static void *commit_list_get_next(const void *a)
 430 {
 431         return ((const struct commit_list *)a)->next;
 432 }
 433
 434 static void commit_list_set_next(void *a, void *next)
 435 {
 436         ((struct commit_list *)a)->next = next;
 437 }
 438
 439 void commit_list_sort_by_date(struct commit_list **list)
 440 {
 441         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 442                                 commit_list_compare_by_date);
 443 }
 444
 445 struct commit *pop_most_recent_commit(struct commit_list **list,
 446                                       unsigned int mark)
 447 {
 448         struct commit *ret = (*list)->item;
 449         struct commit_list *parents = ret->parents;
 450         struct commit_list *old = *list;
 451
 452         *list = (*list)->next;
 453         free(old);
 454
 455         while (parents) {
 456                 struct commit *commit = parents->item;
 457                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 458                         commit->object.flags |= mark;
 459                         commit_list_insert_by_date(commit, list);
 460                 }
 461                 parents = parents->next;
 462         }
 463         return ret;
 464 }
 465
 466 static void clear_commit_marks_1(struct commit_list **plist,
 467                                  struct commit *commit, unsigned int mark)
 468 {
 469         while (commit) {
 470                 struct commit_list *parents;
 471
 472                 if (!(mark & commit->object.flags))
 473                         return;
 474
 475                 commit->object.flags &= ~mark;
 476
 477                 parents = commit->parents;
 478                 if (!parents)
 479                         return;
 480
 481                 while ((parents = parents->next))
 482                         commit_list_insert(parents->item, plist);
 483
 484                 commit = commit->parents->item;
 485         }
 486 }
 487
 488 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 489 {
 490         struct commit_list *list = NULL;
 491
 492         while (nr--) {
 493                 commit_list_insert(*commit, &list);
 494                 commit++;
 495         }
 496         while (list)
 497                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 498 }
 499
 500 void clear_commit_marks(struct commit *commit, unsigned int mark)
 501 {
 502         clear_commit_marks_many(1, &commit, mark);
 503 }
 504
 505 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 506 {
 507         struct object *object;
 508         struct commit *commit;
 509         unsigned int i;
 510
 511         for (i = 0; i < a->nr; i++) {
 512                 object = a->objects[i].item;
 513                 commit = lookup_commit_reference_gently(object->sha1, 1);
 514                 if (commit)
 515                         clear_commit_marks(commit, mark);
 516         }
 517 }
 518
 519 struct commit *pop_commit(struct commit_list **stack)
 520 {
 521         struct commit_list *top = *stack;
 522         struct commit *item = top ? top->item : NULL;
 523
 524         if (top) {
 525                 *stack = top->next;
 526                 free(top);
 527         }
 528         return item;
 529 }
 530
 531 /*
 532  * Topological sort support
 533  */
 534
 535 /* count number of children that have not been emitted */
 536 define_commit_slab(indegree_slab, int);
 537
 538 /* record author-date for each commit object */
 539 define_commit_slab(author_date_slab, unsigned long);
 540
 541 static void record_author_date(struct author_date_slab *author_date,
 542                                struct commit *commit)
 543 {
 544         const char *buf, *line_end;
 545         char *buffer = NULL;
 546         struct ident_split ident;
 547         char *date_end;
 548         unsigned long date;
 549
 550         if (!commit->buffer) {
 551                 unsigned long size;
 552                 enum object_type type;
 553                 buffer = read_sha1_file(commit->object.sha1, &type, &size);
 554                 if (!buffer)
 555                         return;
 556         }
 557
 558         for (buf = commit->buffer ? commit->buffer : buffer;
 559              buf;
 560              buf = line_end + 1) {
 561                 line_end = strchrnul(buf, '\n');
 562                 if (prefixcmp(buf, "author ")) {
 563                         if (!line_end[0] || line_end[1] == '\n')
 564                                 return; /* end of header */
 565                         continue;
 566                 }
 567                 if (split_ident_line(&ident,
 568                                      buf + strlen("author "),
 569                                      line_end - (buf + strlen("author "))) ||
 570                     !ident.date_begin || !ident.date_end)
 571                         goto fail_exit; /* malformed "author" line */
 572                 break;
 573         }
 574
 575         date = strtoul(ident.date_begin, &date_end, 10);
 576         if (date_end != ident.date_end)
 577                 goto fail_exit; /* malformed date */
 578         *(author_date_slab_at(author_date, commit)) = date;
 579
 580 fail_exit:
 581         free(buffer);
 582 }
 583
 584 static int compare_commits_by_author_date(const void *a_, const void *b_,
 585                                           void *cb_data)
 586 {
 587         const struct commit *a = a_, *b = b_;
 588         struct author_date_slab *author_date = cb_data;
 589         unsigned long a_date = *(author_date_slab_at(author_date, a));
 590         unsigned long b_date = *(author_date_slab_at(author_date, b));
 591
 592         /* newer commits with larger date first */
 593         if (a_date < b_date)
 594                 return 1;
 595         else if (a_date > b_date)
 596                 return -1;
 597         return 0;
 598 }
 599
 600 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 601 {
 602         const struct commit *a = a_, *b = b_;
 603         /* newer commits with larger date first */
 604         if (a->date < b->date)
 605                 return 1;
 606         else if (a->date > b->date)
 607                 return -1;
 608         return 0;
 609 }
 610
 611 /*
 612  * Performs an in-place topological sort on the list supplied.
 613  */
 614 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 615 {
 616         struct commit_list *next, *orig = *list;
 617         struct commit_list **pptr;
 618         struct indegree_slab indegree;
 619         struct prio_queue queue;
 620         struct commit *commit;
 621         struct author_date_slab author_date;
 622
 623         if (!orig)
 624                 return;
 625         *list = NULL;
 626
 627         init_indegree_slab(&indegree);
 628         memset(&queue, '\0', sizeof(queue));
 629
 630         switch (sort_order) {
 631         default: /* REV_SORT_IN_GRAPH_ORDER */
 632                 queue.compare = NULL;
 633                 break;
 634         case REV_SORT_BY_COMMIT_DATE:
 635                 queue.compare = compare_commits_by_commit_date;
 636                 break;
 637         case REV_SORT_BY_AUTHOR_DATE:
 638                 init_author_date_slab(&author_date);
 639                 queue.compare = compare_commits_by_author_date;
 640                 queue.cb_data = &author_date;
 641                 break;
 642         }
 643
 644         /* Mark them and clear the indegree */
 645         for (next = orig; next; next = next->next) {
 646                 struct commit *commit = next->item;
 647                 *(indegree_slab_at(&indegree, commit)) = 1;
 648                 /* also record the author dates, if needed */
 649                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 650                         record_author_date(&author_date, commit);
 651         }
 652
 653         /* update the indegree */
 654         for (next = orig; next; next = next->next) {
 655                 struct commit_list *parents = next->item->parents;
 656                 while (parents) {
 657                         struct commit *parent = parents->item;
 658                         int *pi = indegree_slab_at(&indegree, parent);
 659
 660                         if (*pi)
 661                                 (*pi)++;
 662                         parents = parents->next;
 663                 }
 664         }
 665
 666         /*
 667          * find the tips
 668          *
 669          * tips are nodes not reachable from any other node in the list
 670          *
 671          * the tips serve as a starting set for the work queue.
 672          */
 673         for (next = orig; next; next = next->next) {
 674                 struct commit *commit = next->item;
 675
 676                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 677                         prio_queue_put(&queue, commit);
 678         }
 679
 680         /*
 681          * This is unfortunate; the initial tips need to be shown
 682          * in the order given from the revision traversal machinery.
 683          */
 684         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 685                 prio_queue_reverse(&queue);
 686
 687         /* We no longer need the commit list */
 688         free_commit_list(orig);
 689
 690         pptr = list;
 691         *list = NULL;
 692         while ((commit = prio_queue_get(&queue)) != NULL) {
 693                 struct commit_list *parents;
 694
 695                 for (parents = commit->parents; parents ; parents = parents->next) {
 696                         struct commit *parent = parents->item;
 697                         int *pi = indegree_slab_at(&indegree, parent);
 698
 699                         if (!*pi)
 700                                 continue;
 701
 702                         /*
 703                          * parents are only enqueued for emission
 704                          * when all their children have been emitted thereby
 705                          * guaranteeing topological order.
 706                          */
 707                         if (--(*pi) == 1)
 708                                 prio_queue_put(&queue, parent);
 709                 }
 710                 /*
 711                  * all children of commit have already been
 712                  * emitted. we can emit it now.
 713                  */
 714                 *(indegree_slab_at(&indegree, commit)) = 0;
 715
 716                 pptr = &commit_list_insert(commit, pptr)->next;
 717         }
 718
 719         clear_indegree_slab(&indegree);
 720         clear_prio_queue(&queue);
 721         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 722                 clear_author_date_slab(&author_date);
 723 }
 724
 725 /* merge-base stuff */
 726
 727 /* bits #0..15 in revision.h */
 728 #define PARENT1         (1u<<16)
 729 #define PARENT2         (1u<<17)
 730 #define STALE           (1u<<18)
 731 #define RESULT          (1u<<19)
 732
 733 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 734
 735 static struct commit *interesting(struct commit_list *list)
 736 {
 737         while (list) {
 738                 struct commit *commit = list->item;
 739                 list = list->next;
 740                 if (commit->object.flags & STALE)
 741                         continue;
 742                 return commit;
 743         }
 744         return NULL;
 745 }
 746
 747 /* all input commits in one and twos[] must have been parsed! */
 748 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 749 {
 750         struct commit_list *list = NULL;
 751         struct commit_list *result = NULL;
 752         int i;
 753
 754         one->object.flags |= PARENT1;
 755         commit_list_insert_by_date(one, &list);
 756         if (!n)
 757                 return list;
 758         for (i = 0; i < n; i++) {
 759                 twos[i]->object.flags |= PARENT2;
 760                 commit_list_insert_by_date(twos[i], &list);
 761         }
 762
 763         while (interesting(list)) {
 764                 struct commit *commit;
 765                 struct commit_list *parents;
 766                 struct commit_list *next;
 767                 int flags;
 768
 769                 commit = list->item;
 770                 next = list->next;
 771                 free(list);
 772                 list = next;
 773
 774                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 775                 if (flags == (PARENT1 | PARENT2)) {
 776                         if (!(commit->object.flags & RESULT)) {
 777                                 commit->object.flags |= RESULT;
 778                                 commit_list_insert_by_date(commit, &result);
 779                         }
 780                         /* Mark parents of a found merge stale */
 781                         flags |= STALE;
 782                 }
 783                 parents = commit->parents;
 784                 while (parents) {
 785                         struct commit *p = parents->item;
 786                         parents = parents->next;
 787                         if ((p->object.flags & flags) == flags)
 788                                 continue;
 789                         if (parse_commit(p))
 790                                 return NULL;
 791                         p->object.flags |= flags;
 792                         commit_list_insert_by_date(p, &list);
 793                 }
 794         }
 795
 796         free_commit_list(list);
 797         return result;
 798 }
 799
 800 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 801 {
 802         struct commit_list *list = NULL;
 803         struct commit_list *result = NULL;
 804         int i;
 805
 806         for (i = 0; i < n; i++) {
 807                 if (one == twos[i])
 808                         /*
 809                          * We do not mark this even with RESULT so we do not
 810                          * have to clean it up.
 811                          */
 812                         return commit_list_insert(one, &result);
 813         }
 814
 815         if (parse_commit(one))
 816                 return NULL;
 817         for (i = 0; i < n; i++) {
 818                 if (parse_commit(twos[i]))
 819                         return NULL;
 820         }
 821
 822         list = paint_down_to_common(one, n, twos);
 823
 824         while (list) {
 825                 struct commit_list *next = list->next;
 826                 if (!(list->item->object.flags & STALE))
 827                         commit_list_insert_by_date(list->item, &result);
 828                 free(list);
 829                 list = next;
 830         }
 831         return result;
 832 }
 833
 834 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 835 {
 836         struct commit_list *i, *j, *k, *ret = NULL;
 837         struct commit_list **pptr = &ret;
 838
 839         for (i = in; i; i = i->next) {
 840                 if (!ret)
 841                         pptr = &commit_list_insert(i->item, pptr)->next;
 842                 else {
 843                         struct commit_list *new = NULL, *end = NULL;
 844
 845                         for (j = ret; j; j = j->next) {
 846                                 struct commit_list *bases;
 847                                 bases = get_merge_bases(i->item, j->item, 1);
 848                                 if (!new)
 849                                         new = bases;
 850                                 else
 851                                         end->next = bases;
 852                                 for (k = bases; k; k = k->next)
 853                                         end = k;
 854                         }
 855                         ret = new;
 856                 }
 857         }
 858         return ret;
 859 }
 860
 861 static int remove_redundant(struct commit **array, int cnt)
 862 {
 863         /*
 864          * Some commit in the array may be an ancestor of
 865          * another commit.  Move such commit to the end of
 866          * the array, and return the number of commits that
 867          * are independent from each other.
 868          */
 869         struct commit **work;
 870         unsigned char *redundant;
 871         int *filled_index;
 872         int i, j, filled;
 873
 874         work = xcalloc(cnt, sizeof(*work));
 875         redundant = xcalloc(cnt, 1);
 876         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 877
 878         for (i = 0; i < cnt; i++)
 879                 parse_commit(array[i]);
 880         for (i = 0; i < cnt; i++) {
 881                 struct commit_list *common;
 882
 883                 if (redundant[i])
 884                         continue;
 885                 for (j = filled = 0; j < cnt; j++) {
 886                         if (i == j || redundant[j])
 887                                 continue;
 888                         filled_index[filled] = j;
 889                         work[filled++] = array[j];
 890                 }
 891                 common = paint_down_to_common(array[i], filled, work);
 892                 if (array[i]->object.flags & PARENT2)
 893                         redundant[i] = 1;
 894                 for (j = 0; j < filled; j++)
 895                         if (work[j]->object.flags & PARENT1)
 896                                 redundant[filled_index[j]] = 1;
 897                 clear_commit_marks(array[i], all_flags);
 898                 for (j = 0; j < filled; j++)
 899                         clear_commit_marks(work[j], all_flags);
 900                 free_commit_list(common);
 901         }
 902
 903         /* Now collect the result */
 904         memcpy(work, array, sizeof(*array) * cnt);
 905         for (i = filled = 0; i < cnt; i++)
 906                 if (!redundant[i])
 907                         array[filled++] = work[i];
 908         for (j = filled, i = 0; i < cnt; i++)
 909                 if (redundant[i])
 910                         array[j++] = work[i];
 911         free(work);
 912         free(redundant);
 913         free(filled_index);
 914         return filled;
 915 }
 916
 917 struct commit_list *get_merge_bases_many(struct commit *one,
 918                                          int n,
 919                                          struct commit **twos,
 920                                          int cleanup)
 921 {
 922         struct commit_list *list;
 923         struct commit **rslt;
 924         struct commit_list *result;
 925         int cnt, i;
 926
 927         result = merge_bases_many(one, n, twos);
 928         for (i = 0; i < n; i++) {
 929                 if (one == twos[i])
 930                         return result;
 931         }
 932         if (!result || !result->next) {
 933                 if (cleanup) {
 934                         clear_commit_marks(one, all_flags);
 935                         clear_commit_marks_many(n, twos, all_flags);
 936                 }
 937                 return result;
 938         }
 939
 940         /* There are more than one */
 941         cnt = 0;
 942         list = result;
 943         while (list) {
 944                 list = list->next;
 945                 cnt++;
 946         }
 947         rslt = xcalloc(cnt, sizeof(*rslt));
 948         for (list = result, i = 0; list; list = list->next)
 949                 rslt[i++] = list->item;
 950         free_commit_list(result);
 951
 952         clear_commit_marks(one, all_flags);
 953         clear_commit_marks_many(n, twos, all_flags);
 954
 955         cnt = remove_redundant(rslt, cnt);
 956         result = NULL;
 957         for (i = 0; i < cnt; i++)
 958                 commit_list_insert_by_date(rslt[i], &result);
 959         free(rslt);
 960         return result;
 961 }
 962
 963 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 964                                     int cleanup)
 965 {
 966         return get_merge_bases_many(one, 1, &two, cleanup);
 967 }
 968
 969 /*
 970  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 971  */
 972 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 973 {
 974         if (!with_commit)
 975                 return 1;
 976         while (with_commit) {
 977                 struct commit *other;
 978
 979                 other = with_commit->item;
 980                 with_commit = with_commit->next;
 981                 if (in_merge_bases(other, commit))
 982                         return 1;
 983         }
 984         return 0;
 985 }
 986
 987 /*
 988  * Is "commit" an ancestor of one of the "references"?
 989  */
 990 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 991 {
 992         struct commit_list *bases;
 993         int ret = 0, i;
 994
 995         if (parse_commit(commit))
 996                 return ret;
 997         for (i = 0; i < nr_reference; i++)
 998                 if (parse_commit(reference[i]))
 999                         return ret;
1000
1001         bases = paint_down_to_common(commit, nr_reference, reference);
1002         if (commit->object.flags & PARENT2)
1003                 ret = 1;
1004         clear_commit_marks(commit, all_flags);
1005         clear_commit_marks_many(nr_reference, reference, all_flags);
1006         free_commit_list(bases);
1007         return ret;
1008 }
1009
1010 /*
1011  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1012  */
1013 int in_merge_bases(struct commit *commit, struct commit *reference)
1014 {
1015         return in_merge_bases_many(commit, 1, &reference);
1016 }
1017
1018 struct commit_list *reduce_heads(struct commit_list *heads)
1019 {
1020         struct commit_list *p;
1021         struct commit_list *result = NULL, **tail = &result;
1022         struct commit **array;
1023         int num_head, i;
1024
1025         if (!heads)
1026                 return NULL;
1027
1028         /* Uniquify */
1029         for (p = heads; p; p = p->next)
1030                 p->item->object.flags &= ~STALE;
1031         for (p = heads, num_head = 0; p; p = p->next) {
1032                 if (p->item->object.flags & STALE)
1033                         continue;
1034                 p->item->object.flags |= STALE;
1035                 num_head++;
1036         }
1037         array = xcalloc(sizeof(*array), num_head);
1038         for (p = heads, i = 0; p; p = p->next) {
1039                 if (p->item->object.flags & STALE) {
1040                         array[i++] = p->item;
1041                         p->item->object.flags &= ~STALE;
1042                 }
1043         }
1044         num_head = remove_redundant(array, num_head);
1045         for (i = 0; i < num_head; i++)
1046                 tail = &commit_list_insert(array[i], tail)->next;
1047         return result;
1048 }
1049
1050 static const char gpg_sig_header[] = "gpgsig";
1051 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1052
1053 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1054 {
1055         struct strbuf sig = STRBUF_INIT;
1056         int inspos, copypos;
1057
1058         /* find the end of the header */
1059         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1060
1061         if (!keyid || !*keyid)
1062                 keyid = get_signing_key();
1063         if (sign_buffer(buf, &sig, keyid)) {
1064                 strbuf_release(&sig);
1065                 return -1;
1066         }
1067
1068         for (copypos = 0; sig.buf[copypos]; ) {
1069                 const char *bol = sig.buf + copypos;
1070                 const char *eol = strchrnul(bol, '\n');
1071                 int len = (eol - bol) + !!*eol;
1072
1073                 if (!copypos) {
1074                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1075                         inspos += gpg_sig_header_len;
1076                 }
1077                 strbuf_insert(buf, inspos++, " ", 1);
1078                 strbuf_insert(buf, inspos, bol, len);
1079                 inspos += len;
1080                 copypos += len;
1081         }
1082         strbuf_release(&sig);
1083         return 0;
1084 }
1085
1086 int parse_signed_commit(const unsigned char *sha1,
1087                         struct strbuf *payload, struct strbuf *signature)
1088 {
1089         unsigned long size;
1090         enum object_type type;
1091         char *buffer = read_sha1_file(sha1, &type, &size);
1092         int in_signature, saw_signature = -1;
1093         char *line, *tail;
1094
1095         if (!buffer || type != OBJ_COMMIT)
1096                 goto cleanup;
1097
1098         line = buffer;
1099         tail = buffer + size;
1100         in_signature = 0;
1101         saw_signature = 0;
1102         while (line < tail) {
1103                 const char *sig = NULL;
1104                 char *next = memchr(line, '\n', tail - line);
1105
1106                 next = next ? next + 1 : tail;
1107                 if (in_signature && line[0] == ' ')
1108                         sig = line + 1;
1109                 else if (!prefixcmp(line, gpg_sig_header) &&
1110                          line[gpg_sig_header_len] == ' ')
1111                         sig = line + gpg_sig_header_len + 1;
1112                 if (sig) {
1113                         strbuf_add(signature, sig, next - sig);
1114                         saw_signature = 1;
1115                         in_signature = 1;
1116                 } else {
1117                         if (*line == '\n')
1118                                 /* dump the whole remainder of the buffer */
1119                                 next = tail;
1120                         strbuf_add(payload, line, next - line);
1121                         in_signature = 0;
1122                 }
1123                 line = next;
1124         }
1125  cleanup:
1126         free(buffer);
1127         return saw_signature;
1128 }
1129
1130 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1131 {
1132         struct merge_remote_desc *desc;
1133         struct commit_extra_header *mergetag;
1134         char *buf;
1135         unsigned long size, len;
1136         enum object_type type;
1137
1138         desc = merge_remote_util(parent);
1139         if (!desc || !desc->obj)
1140                 return;
1141         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1142         if (!buf || type != OBJ_TAG)
1143                 goto free_return;
1144         len = parse_signature(buf, size);
1145         if (size == len)
1146                 goto free_return;
1147         /*
1148          * We could verify this signature and either omit the tag when
1149          * it does not validate, but the integrator may not have the
1150          * public key of the signer of the tag he is merging, while a
1151          * later auditor may have it while auditing, so let's not run
1152          * verify-signed-buffer here for now...
1153          *
1154          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1155          *      warn("warning: signed tag unverified.");
1156          */
1157         mergetag = xcalloc(1, sizeof(*mergetag));
1158         mergetag->key = xstrdup("mergetag");
1159         mergetag->value = buf;
1160         mergetag->len = size;
1161
1162         **tail = mergetag;
1163         *tail = &mergetag->next;
1164         return;
1165
1166 free_return:
1167         free(buf);
1168 }
1169
1170 static struct {
1171         char result;
1172         const char *check;
1173 } sigcheck_gpg_status[] = {
1174         { 'G', "\n[GNUPG:] GOODSIG " },
1175         { 'B', "\n[GNUPG:] BADSIG " },
1176         { 'U', "\n[GNUPG:] TRUST_NEVER" },
1177         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1178 };
1179
1180 static void parse_gpg_output(struct signature_check *sigc)
1181 {
1182         const char *buf = sigc->gpg_status;
1183         int i;
1184
1185         /* Iterate over all search strings */
1186         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1187                 const char *found, *next;
1188
1189                 if (!prefixcmp(buf, sigcheck_gpg_status[i].check + 1)) {
1190                         /* At the very beginning of the buffer */
1191                         found = buf + strlen(sigcheck_gpg_status[i].check + 1);
1192                 } else {
1193                         found = strstr(buf, sigcheck_gpg_status[i].check);
1194                         if (!found)
1195                                 continue;
1196                         found += strlen(sigcheck_gpg_status[i].check);
1197                 }
1198                 sigc->result = sigcheck_gpg_status[i].result;
1199                 /* The trust messages are not followed by key/signer information */
1200                 if (sigc->result != 'U') {
1201                         sigc->key = xmemdupz(found, 16);
1202                         found += 17;
1203                         next = strchrnul(found, '\n');
1204                         sigc->signer = xmemdupz(found, next - found);
1205                 }
1206         }
1207 }
1208
1209 void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1210 {
1211         struct strbuf payload = STRBUF_INIT;
1212         struct strbuf signature = STRBUF_INIT;
1213         struct strbuf gpg_output = STRBUF_INIT;
1214         struct strbuf gpg_status = STRBUF_INIT;
1215         int status;
1216
1217         sigc->result = 'N';
1218
1219         if (parse_signed_commit(commit->object.sha1,
1220                                 &payload, &signature) <= 0)
1221                 goto out;
1222         status = verify_signed_buffer(payload.buf, payload.len,
1223                                       signature.buf, signature.len,
1224                                       &gpg_output, &gpg_status);
1225         if (status && !gpg_output.len)
1226                 goto out;
1227         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1228         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1229         parse_gpg_output(sigc);
1230
1231  out:
1232         strbuf_release(&gpg_status);
1233         strbuf_release(&gpg_output);
1234         strbuf_release(&payload);
1235         strbuf_release(&signature);
1236 }
1237
1238
1239
1240 void append_merge_tag_headers(struct commit_list *parents,
1241                               struct commit_extra_header ***tail)
1242 {
1243         while (parents) {
1244                 struct commit *parent = parents->item;
1245                 handle_signed_tag(parent, tail);
1246                 parents = parents->next;
1247         }
1248 }
1249
1250 static void add_extra_header(struct strbuf *buffer,
1251                              struct commit_extra_header *extra)
1252 {
1253         strbuf_addstr(buffer, extra->key);
1254         if (extra->len)
1255                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1256         else
1257                 strbuf_addch(buffer, '\n');
1258 }
1259
1260 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1261                                                       const char **exclude)
1262 {
1263         struct commit_extra_header *extra = NULL;
1264         unsigned long size;
1265         enum object_type type;
1266         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1267         if (buffer && type == OBJ_COMMIT)
1268                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1269         free(buffer);
1270         return extra;
1271 }
1272
1273 static inline int standard_header_field(const char *field, size_t len)
1274 {
1275         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1276                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1277                 (len == 6 && !memcmp(field, "author ", 7)) ||
1278                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1279                 (len == 8 && !memcmp(field, "encoding ", 9)));
1280 }
1281
1282 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1283 {
1284         if (!exclude)
1285                 return 0;
1286
1287         while (*exclude) {
1288                 size_t xlen = strlen(*exclude);
1289                 if (len == xlen &&
1290                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1291                         return 1;
1292                 exclude++;
1293         }
1294         return 0;
1295 }
1296
1297 static struct commit_extra_header *read_commit_extra_header_lines(
1298         const char *buffer, size_t size,
1299         const char **exclude)
1300 {
1301         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1302         const char *line, *next, *eof, *eob;
1303         struct strbuf buf = STRBUF_INIT;
1304
1305         for (line = buffer, eob = line + size;
1306              line < eob && *line != '\n';
1307              line = next) {
1308                 next = memchr(line, '\n', eob - line);
1309                 next = next ? next + 1 : eob;
1310                 if (*line == ' ') {
1311                         /* continuation */
1312                         if (it)
1313                                 strbuf_add(&buf, line + 1, next - (line + 1));
1314                         continue;
1315                 }
1316                 if (it)
1317                         it->value = strbuf_detach(&buf, &it->len);
1318                 strbuf_reset(&buf);
1319                 it = NULL;
1320
1321                 eof = strchr(line, ' ');
1322                 if (next <= eof)
1323                         eof = next;
1324
1325                 if (standard_header_field(line, eof - line) ||
1326                     excluded_header_field(line, eof - line, exclude))
1327                         continue;
1328
1329                 it = xcalloc(1, sizeof(*it));
1330                 it->key = xmemdupz(line, eof-line);
1331                 *tail = it;
1332                 tail = &it->next;
1333                 if (eof + 1 < next)
1334                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1335         }
1336         if (it)
1337                 it->value = strbuf_detach(&buf, &it->len);
1338         return extra;
1339 }
1340
1341 void free_commit_extra_headers(struct commit_extra_header *extra)
1342 {
1343         while (extra) {
1344                 struct commit_extra_header *next = extra->next;
1345                 free(extra->key);
1346                 free(extra->value);
1347                 free(extra);
1348                 extra = next;
1349         }
1350 }
1351
1352 int commit_tree(const struct strbuf *msg, unsigned char *tree,
1353                 struct commit_list *parents, unsigned char *ret,
1354                 const char *author, const char *sign_commit)
1355 {
1356         struct commit_extra_header *extra = NULL, **tail = &extra;
1357         int result;
1358
1359         append_merge_tag_headers(parents, &tail);
1360         result = commit_tree_extended(msg, tree, parents, ret,
1361                                       author, sign_commit, extra);
1362         free_commit_extra_headers(extra);
1363         return result;
1364 }
1365
1366 static int find_invalid_utf8(const char *buf, int len)
1367 {
1368         int offset = 0;
1369         static const unsigned int max_codepoint[] = {
1370                 0x7f, 0x7ff, 0xffff, 0x10ffff
1371         };
1372
1373         while (len) {
1374                 unsigned char c = *buf++;
1375                 int bytes, bad_offset;
1376                 unsigned int codepoint;
1377                 unsigned int min_val, max_val;
1378
1379                 len--;
1380                 offset++;
1381
1382                 /* Simple US-ASCII? No worries. */
1383                 if (c < 0x80)
1384                         continue;
1385
1386                 bad_offset = offset-1;
1387
1388                 /*
1389                  * Count how many more high bits set: that's how
1390                  * many more bytes this sequence should have.
1391                  */
1392                 bytes = 0;
1393                 while (c & 0x40) {
1394                         c <<= 1;
1395                         bytes++;
1396                 }
1397
1398                 /*
1399                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1400                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1401                  */
1402                 if (bytes < 1 || 3 < bytes)
1403                         return bad_offset;
1404
1405                 /* Do we *have* that many bytes? */
1406                 if (len < bytes)
1407                         return bad_offset;
1408
1409                 /*
1410                  * Place the encoded bits at the bottom of the value and compute the
1411                  * valid range.
1412                  */
1413                 codepoint = (c & 0x7f) >> bytes;
1414                 min_val = max_codepoint[bytes-1] + 1;
1415                 max_val = max_codepoint[bytes];
1416
1417                 offset += bytes;
1418                 len -= bytes;
1419
1420                 /* And verify that they are good continuation bytes */
1421                 do {
1422                         codepoint <<= 6;
1423                         codepoint |= *buf & 0x3f;
1424                         if ((*buf++ & 0xc0) != 0x80)
1425                                 return bad_offset;
1426                 } while (--bytes);
1427
1428                 /* Reject codepoints that are out of range for the sequence length. */
1429                 if (codepoint < min_val || codepoint > max_val)
1430                         return bad_offset;
1431                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1432                 if ((codepoint & 0x1ff800) == 0xd800)
1433                         return bad_offset;
1434                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1435                 if ((codepoint & 0xfffe) == 0xfffe)
1436                         return bad_offset;
1437                 /* So are anything in the range U+FDD0..U+FDEF. */
1438                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1439                         return bad_offset;
1440         }
1441         return -1;
1442 }
1443
1444 /*
1445  * This verifies that the buffer is in proper utf8 format.
1446  *
1447  * If it isn't, it assumes any non-utf8 characters are Latin1,
1448  * and does the conversion.
1449  */
1450 static int verify_utf8(struct strbuf *buf)
1451 {
1452         int ok = 1;
1453         long pos = 0;
1454
1455         for (;;) {
1456                 int bad;
1457                 unsigned char c;
1458                 unsigned char replace[2];
1459
1460                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1461                 if (bad < 0)
1462                         return ok;
1463                 pos += bad;
1464                 ok = 0;
1465                 c = buf->buf[pos];
1466                 strbuf_remove(buf, pos, 1);
1467
1468                 /* We know 'c' must be in the range 128-255 */
1469                 replace[0] = 0xc0 + (c >> 6);
1470                 replace[1] = 0x80 + (c & 0x3f);
1471                 strbuf_insert(buf, pos, replace, 2);
1472                 pos += 2;
1473         }
1474 }
1475
1476 static const char commit_utf8_warn[] =
1477 "Warning: commit message did not conform to UTF-8.\n"
1478 "You may want to amend it after fixing the message, or set the config\n"
1479 "variable i18n.commitencoding to the encoding your project uses.\n";
1480
1481 int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1482                          struct commit_list *parents, unsigned char *ret,
1483                          const char *author, const char *sign_commit,
1484                          struct commit_extra_header *extra)
1485 {
1486         int result;
1487         int encoding_is_utf8;
1488         struct strbuf buffer;
1489
1490         assert_sha1_type(tree, OBJ_TREE);
1491
1492         if (memchr(msg->buf, '\0', msg->len))
1493                 return error("a NUL byte in commit log message not allowed.");
1494
1495         /* Not having i18n.commitencoding is the same as having utf-8 */
1496         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1497
1498         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1499         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1500
1501         /*
1502          * NOTE! This ordering means that the same exact tree merged with a
1503          * different order of parents will be a _different_ changeset even
1504          * if everything else stays the same.
1505          */
1506         while (parents) {
1507                 struct commit_list *next = parents->next;
1508                 struct commit *parent = parents->item;
1509
1510                 strbuf_addf(&buffer, "parent %s\n",
1511                             sha1_to_hex(parent->object.sha1));
1512                 free(parents);
1513                 parents = next;
1514         }
1515
1516         /* Person/date information */
1517         if (!author)
1518                 author = git_author_info(IDENT_STRICT);
1519         strbuf_addf(&buffer, "author %s\n", author);
1520         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1521         if (!encoding_is_utf8)
1522                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1523
1524         while (extra) {
1525                 add_extra_header(&buffer, extra);
1526                 extra = extra->next;
1527         }
1528         strbuf_addch(&buffer, '\n');
1529
1530         /* And add the comment */
1531         strbuf_addbuf(&buffer, msg);
1532
1533         /* And check the encoding */
1534         if (encoding_is_utf8 && !verify_utf8(&buffer))
1535                 fprintf(stderr, commit_utf8_warn);
1536
1537         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1538                 return -1;
1539
1540         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1541         strbuf_release(&buffer);
1542         return result;
1543 }
1544
1545 struct commit *get_merge_parent(const char *name)
1546 {
1547         struct object *obj;
1548         struct commit *commit;
1549         unsigned char sha1[20];
1550         if (get_sha1(name, sha1))
1551                 return NULL;
1552         obj = parse_object(sha1);
1553         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1554         if (commit && !commit->util) {
1555                 struct merge_remote_desc *desc;
1556                 desc = xmalloc(sizeof(*desc));
1557                 desc->obj = obj;
1558                 desc->name = strdup(name);
1559                 commit->util = desc;
1560         }
1561         return commit;
1562 }
1563
1564 /*
1565  * Append a commit to the end of the commit_list.
1566  *
1567  * next starts by pointing to the variable that holds the head of an
1568  * empty commit_list, and is updated to point to the "next" field of
1569  * the last item on the list as new commits are appended.
1570  *
1571  * Usage example:
1572  *
1573  *     struct commit_list *list;
1574  *     struct commit_list **next = &list;
1575  *
1576  *     next = commit_list_append(c1, next);
1577  *     next = commit_list_append(c2, next);
1578  *     assert(commit_list_count(list) == 2);
1579  *     return list;
1580  */
1581 struct commit_list **commit_list_append(struct commit *commit,
1582                                         struct commit_list **next)
1583 {
1584         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1585         new->item = commit;
1586         *next = new;
1587         new->next = NULL;
1588         return &new->next;
1589 }
1590
1591 void print_commit_list(struct commit_list *list,
1592                        const char *format_cur,
1593                        const char *format_last)
1594 {
1595         for ( ; list; list = list->next) {
1596                 const char *format = list->next ? format_cur : format_last;
1597                 printf(format, sha1_to_hex(list->item->object.sha1));
1598         }
1599 }