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 #include "sha1-lookup.h"
  14
  15 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  16
  17 int save_commit_buffer = 1;
  18
  19 const char *commit_type = "commit";
  20 static int commit_count;
  21
  22 static struct commit *check_commit(struct object *obj,
  23                                    const unsigned char *sha1,
  24                                    int quiet)
  25 {
  26         if (obj->type != OBJ_COMMIT) {
  27                 if (!quiet)
  28                         error("Object %s is a %s, not a commit",
  29                               sha1_to_hex(sha1), typename(obj->type));
  30                 return NULL;
  31         }
  32         return (struct commit *) obj;
  33 }
  34
  35 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  36                                               int quiet)
  37 {
  38         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  39
  40         if (!obj)
  41                 return NULL;
  42         return check_commit(obj, sha1, quiet);
  43 }
  44
  45 struct commit *lookup_commit_reference(const unsigned char *sha1)
  46 {
  47         return lookup_commit_reference_gently(sha1, 0);
  48 }
  49
  50 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  51 {
  52         struct commit *c = lookup_commit_reference(sha1);
  53         if (!c)
  54                 die(_("could not parse %s"), ref_name);
  55         if (hashcmp(sha1, c->object.sha1)) {
  56                 warning(_("%s %s is not a commit!"),
  57                         ref_name, sha1_to_hex(sha1));
  58         }
  59         return c;
  60 }
  61
  62 struct commit *lookup_commit(const unsigned char *sha1)
  63 {
  64         struct object *obj = lookup_object(sha1);
  65         if (!obj) {
  66                 struct commit *c = alloc_commit_node();
  67                 c->index = commit_count++;
  68                 return create_object(sha1, OBJ_COMMIT, c);
  69         }
  70         if (!obj->type)
  71                 obj->type = OBJ_COMMIT;
  72         return check_commit(obj, sha1, 0);
  73 }
  74
  75 struct commit *lookup_commit_reference_by_name(const char *name)
  76 {
  77         unsigned char sha1[20];
  78         struct commit *commit;
  79
  80         if (get_sha1_committish(name, sha1))
  81                 return NULL;
  82         commit = lookup_commit_reference(sha1);
  83         if (parse_commit(commit))
  84                 return NULL;
  85         return commit;
  86 }
  87
  88 static unsigned long parse_commit_date(const char *buf, const char *tail)
  89 {
  90         const char *dateptr;
  91
  92         if (buf + 6 >= tail)
  93                 return 0;
  94         if (memcmp(buf, "author", 6))
  95                 return 0;
  96         while (buf < tail && *buf++ != '\n')
  97                 /* nada */;
  98         if (buf + 9 >= tail)
  99                 return 0;
 100         if (memcmp(buf, "committer", 9))
 101                 return 0;
 102         while (buf < tail && *buf++ != '>')
 103                 /* nada */;
 104         if (buf >= tail)
 105                 return 0;
 106         dateptr = buf;
 107         while (buf < tail && *buf++ != '\n')
 108                 /* nada */;
 109         if (buf >= tail)
 110                 return 0;
 111         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 112         return strtoul(dateptr, NULL, 10);
 113 }
 114
 115 static struct commit_graft **commit_graft;
 116 static int commit_graft_alloc, commit_graft_nr;
 117
 118 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 119 {
 120         struct commit_graft **commit_graft_table = table;
 121         return commit_graft_table[index]->sha1;
 122 }
 123
 124 static int commit_graft_pos(const unsigned char *sha1)
 125 {
 126         return sha1_pos(sha1, commit_graft, commit_graft_nr,
 127                         commit_graft_sha1_access);
 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         ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 145         commit_graft_nr++;
 146         if (pos < commit_graft_nr)
 147                 memmove(commit_graft + pos + 1,
 148                         commit_graft + pos,
 149                         (commit_graft_nr - pos - 1) *
 150                         sizeof(*commit_graft));
 151         commit_graft[pos] = graft;
 152         return 0;
 153 }
 154
 155 struct commit_graft *read_graft_line(char *buf, int len)
 156 {
 157         /* The format is just "Commit Parent1 Parent2 ...\n" */
 158         int i;
 159         struct commit_graft *graft = NULL;
 160
 161         while (len && isspace(buf[len-1]))
 162                 buf[--len] = '\0';
 163         if (buf[0] == '#' || buf[0] == '\0')
 164                 return NULL;
 165         if ((len + 1) % 41)
 166                 goto bad_graft_data;
 167         i = (len + 1) / 41 - 1;
 168         graft = xmalloc(sizeof(*graft) + 20 * i);
 169         graft->nr_parent = i;
 170         if (get_sha1_hex(buf, graft->sha1))
 171                 goto bad_graft_data;
 172         for (i = 40; i < len; i += 41) {
 173                 if (buf[i] != ' ')
 174                         goto bad_graft_data;
 175                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 176                         goto bad_graft_data;
 177         }
 178         return graft;
 179
 180 bad_graft_data:
 181         error("bad graft data: %s", buf);
 182         free(graft);
 183         return NULL;
 184 }
 185
 186 static int read_graft_file(const char *graft_file)
 187 {
 188         FILE *fp = fopen(graft_file, "r");
 189         struct strbuf buf = STRBUF_INIT;
 190         if (!fp)
 191                 return -1;
 192         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 193                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 194                 struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 195                 if (!graft)
 196                         continue;
 197                 if (register_commit_graft(graft, 1))
 198                         error("duplicate graft data: %s", buf.buf);
 199         }
 200         fclose(fp);
 201         strbuf_release(&buf);
 202         return 0;
 203 }
 204
 205 static void prepare_commit_graft(void)
 206 {
 207         static int commit_graft_prepared;
 208         char *graft_file;
 209
 210         if (commit_graft_prepared)
 211                 return;
 212         graft_file = get_graft_file();
 213         read_graft_file(graft_file);
 214         /* make sure shallows are read */
 215         is_repository_shallow();
 216         commit_graft_prepared = 1;
 217 }
 218
 219 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 220 {
 221         int pos;
 222         prepare_commit_graft();
 223         pos = commit_graft_pos(sha1);
 224         if (pos < 0)
 225                 return NULL;
 226         return commit_graft[pos];
 227 }
 228
 229 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 230 {
 231         int i, ret;
 232         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 233                 ret = fn(commit_graft[i], cb_data);
 234         return ret;
 235 }
 236
 237 int unregister_shallow(const unsigned char *sha1)
 238 {
 239         int pos = commit_graft_pos(sha1);
 240         if (pos < 0)
 241                 return -1;
 242         if (pos + 1 < commit_graft_nr)
 243                 memmove(commit_graft + pos, commit_graft + pos + 1,
 244                                 sizeof(struct commit_graft *)
 245                                 * (commit_graft_nr - pos - 1));
 246         commit_graft_nr--;
 247         return 0;
 248 }
 249
 250 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 251 {
 252         const char *tail = buffer;
 253         const char *bufptr = buffer;
 254         unsigned char parent[20];
 255         struct commit_list **pptr;
 256         struct commit_graft *graft;
 257
 258         if (item->object.parsed)
 259                 return 0;
 260         item->object.parsed = 1;
 261         tail += size;
 262         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 263                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 264         if (get_sha1_hex(bufptr + 5, parent) < 0)
 265                 return error("bad tree pointer in commit %s",
 266                              sha1_to_hex(item->object.sha1));
 267         item->tree = lookup_tree(parent);
 268         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 269         pptr = &item->parents;
 270
 271         graft = lookup_commit_graft(item->object.sha1);
 272         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 273                 struct commit *new_parent;
 274
 275                 if (tail <= bufptr + 48 ||
 276                     get_sha1_hex(bufptr + 7, parent) ||
 277                     bufptr[47] != '\n')
 278                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 279                 bufptr += 48;
 280                 /*
 281                  * The clone is shallow if nr_parent < 0, and we must
 282                  * not traverse its real parents even when we unhide them.
 283                  */
 284                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 285                         continue;
 286                 new_parent = lookup_commit(parent);
 287                 if (new_parent)
 288                         pptr = &commit_list_insert(new_parent, pptr)->next;
 289         }
 290         if (graft) {
 291                 int i;
 292                 struct commit *new_parent;
 293                 for (i = 0; i < graft->nr_parent; i++) {
 294                         new_parent = lookup_commit(graft->parent[i]);
 295                         if (!new_parent)
 296                                 continue;
 297                         pptr = &commit_list_insert(new_parent, pptr)->next;
 298                 }
 299         }
 300         item->date = parse_commit_date(bufptr, tail);
 301
 302         return 0;
 303 }
 304
 305 int parse_commit(struct commit *item)
 306 {
 307         enum object_type type;
 308         void *buffer;
 309         unsigned long size;
 310         int ret;
 311
 312         if (!item)
 313                 return -1;
 314         if (item->object.parsed)
 315                 return 0;
 316         buffer = read_sha1_file(item->object.sha1, &type, &size);
 317         if (!buffer)
 318                 return error("Could not read %s",
 319                              sha1_to_hex(item->object.sha1));
 320         if (type != OBJ_COMMIT) {
 321                 free(buffer);
 322                 return error("Object %s not a commit",
 323                              sha1_to_hex(item->object.sha1));
 324         }
 325         ret = parse_commit_buffer(item, buffer, size);
 326         if (save_commit_buffer && !ret) {
 327                 item->buffer = buffer;
 328                 return 0;
 329         }
 330         free(buffer);
 331         return ret;
 332 }
 333
 334 void parse_commit_or_die(struct commit *item)
 335 {
 336         if (parse_commit(item))
 337                 die("unable to parse commit %s",
 338                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 339 }
 340
 341 int find_commit_subject(const char *commit_buffer, const char **subject)
 342 {
 343         const char *eol;
 344         const char *p = commit_buffer;
 345
 346         while (*p && (*p != '\n' || p[1] != '\n'))
 347                 p++;
 348         if (*p) {
 349                 p += 2;
 350                 for (eol = p; *eol && *eol != '\n'; eol++)
 351                         ; /* do nothing */
 352         } else
 353                 eol = p;
 354
 355         *subject = p;
 356
 357         return eol - p;
 358 }
 359
 360 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 361 {
 362         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 363         new_list->item = item;
 364         new_list->next = *list_p;
 365         *list_p = new_list;
 366         return new_list;
 367 }
 368
 369 unsigned commit_list_count(const struct commit_list *l)
 370 {
 371         unsigned c = 0;
 372         for (; l; l = l->next )
 373                 c++;
 374         return c;
 375 }
 376
 377 struct commit_list *copy_commit_list(struct commit_list *list)
 378 {
 379         struct commit_list *head = NULL;
 380         struct commit_list **pp = &head;
 381         while (list) {
 382                 struct commit_list *new;
 383                 new = xmalloc(sizeof(struct commit_list));
 384                 new->item = list->item;
 385                 new->next = NULL;
 386                 *pp = new;
 387                 pp = &new->next;
 388                 list = list->next;
 389         }
 390         return head;
 391 }
 392
 393 void free_commit_list(struct commit_list *list)
 394 {
 395         while (list) {
 396                 struct commit_list *temp = list;
 397                 list = temp->next;
 398                 free(temp);
 399         }
 400 }
 401
 402 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 403 {
 404         struct commit_list **pp = list;
 405         struct commit_list *p;
 406         while ((p = *pp) != NULL) {
 407                 if (p->item->date < item->date) {
 408                         break;
 409                 }
 410                 pp = &p->next;
 411         }
 412         return commit_list_insert(item, pp);
 413 }
 414
 415 static int commit_list_compare_by_date(const void *a, const void *b)
 416 {
 417         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 418         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 419         if (a_date < b_date)
 420                 return 1;
 421         if (a_date > b_date)
 422                 return -1;
 423         return 0;
 424 }
 425
 426 static void *commit_list_get_next(const void *a)
 427 {
 428         return ((const struct commit_list *)a)->next;
 429 }
 430
 431 static void commit_list_set_next(void *a, void *next)
 432 {
 433         ((struct commit_list *)a)->next = next;
 434 }
 435
 436 void commit_list_sort_by_date(struct commit_list **list)
 437 {
 438         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 439                                 commit_list_compare_by_date);
 440 }
 441
 442 struct commit *pop_most_recent_commit(struct commit_list **list,
 443                                       unsigned int mark)
 444 {
 445         struct commit *ret = (*list)->item;
 446         struct commit_list *parents = ret->parents;
 447         struct commit_list *old = *list;
 448
 449         *list = (*list)->next;
 450         free(old);
 451
 452         while (parents) {
 453                 struct commit *commit = parents->item;
 454                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 455                         commit->object.flags |= mark;
 456                         commit_list_insert_by_date(commit, list);
 457                 }
 458                 parents = parents->next;
 459         }
 460         return ret;
 461 }
 462
 463 static void clear_commit_marks_1(struct commit_list **plist,
 464                                  struct commit *commit, unsigned int mark)
 465 {
 466         while (commit) {
 467                 struct commit_list *parents;
 468
 469                 if (!(mark & commit->object.flags))
 470                         return;
 471
 472                 commit->object.flags &= ~mark;
 473
 474                 parents = commit->parents;
 475                 if (!parents)
 476                         return;
 477
 478                 while ((parents = parents->next))
 479                         commit_list_insert(parents->item, plist);
 480
 481                 commit = commit->parents->item;
 482         }
 483 }
 484
 485 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 486 {
 487         struct commit_list *list = NULL;
 488
 489         while (nr--) {
 490                 commit_list_insert(*commit, &list);
 491                 commit++;
 492         }
 493         while (list)
 494                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 495 }
 496
 497 void clear_commit_marks(struct commit *commit, unsigned int mark)
 498 {
 499         clear_commit_marks_many(1, &commit, mark);
 500 }
 501
 502 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 503 {
 504         struct object *object;
 505         struct commit *commit;
 506         unsigned int i;
 507
 508         for (i = 0; i < a->nr; i++) {
 509                 object = a->objects[i].item;
 510                 commit = lookup_commit_reference_gently(object->sha1, 1);
 511                 if (commit)
 512                         clear_commit_marks(commit, mark);
 513         }
 514 }
 515
 516 struct commit *pop_commit(struct commit_list **stack)
 517 {
 518         struct commit_list *top = *stack;
 519         struct commit *item = top ? top->item : NULL;
 520
 521         if (top) {
 522                 *stack = top->next;
 523                 free(top);
 524         }
 525         return item;
 526 }
 527
 528 /*
 529  * Topological sort support
 530  */
 531
 532 /* count number of children that have not been emitted */
 533 define_commit_slab(indegree_slab, int);
 534
 535 /* record author-date for each commit object */
 536 define_commit_slab(author_date_slab, unsigned long);
 537
 538 static void record_author_date(struct author_date_slab *author_date,
 539                                struct commit *commit)
 540 {
 541         const char *buf, *line_end, *ident_line;
 542         char *buffer = NULL;
 543         struct ident_split ident;
 544         char *date_end;
 545         unsigned long date;
 546
 547         if (!commit->buffer) {
 548                 unsigned long size;
 549                 enum object_type type;
 550                 buffer = read_sha1_file(commit->object.sha1, &type, &size);
 551                 if (!buffer)
 552                         return;
 553         }
 554
 555         for (buf = commit->buffer ? commit->buffer : buffer;
 556              buf;
 557              buf = line_end + 1) {
 558                 line_end = strchrnul(buf, '\n');
 559                 if (!skip_prefix(buf, "author ", &ident_line)) {
 560                         if (!line_end[0] || line_end[1] == '\n')
 561                                 return; /* end of header */
 562                         continue;
 563                 }
 564                 if (split_ident_line(&ident,
 565                                      ident_line, line_end - ident_line) ||
 566                     !ident.date_begin || !ident.date_end)
 567                         goto fail_exit; /* malformed "author" line */
 568                 break;
 569         }
 570
 571         date = strtoul(ident.date_begin, &date_end, 10);
 572         if (date_end != ident.date_end)
 573                 goto fail_exit; /* malformed date */
 574         *(author_date_slab_at(author_date, commit)) = date;
 575
 576 fail_exit:
 577         free(buffer);
 578 }
 579
 580 static int compare_commits_by_author_date(const void *a_, const void *b_,
 581                                           void *cb_data)
 582 {
 583         const struct commit *a = a_, *b = b_;
 584         struct author_date_slab *author_date = cb_data;
 585         unsigned long a_date = *(author_date_slab_at(author_date, a));
 586         unsigned long b_date = *(author_date_slab_at(author_date, b));
 587
 588         /* newer commits with larger date first */
 589         if (a_date < b_date)
 590                 return 1;
 591         else if (a_date > b_date)
 592                 return -1;
 593         return 0;
 594 }
 595
 596 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 597 {
 598         const struct commit *a = a_, *b = b_;
 599         /* newer commits with larger date first */
 600         if (a->date < b->date)
 601                 return 1;
 602         else if (a->date > b->date)
 603                 return -1;
 604         return 0;
 605 }
 606
 607 /*
 608  * Performs an in-place topological sort on the list supplied.
 609  */
 610 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 611 {
 612         struct commit_list *next, *orig = *list;
 613         struct commit_list **pptr;
 614         struct indegree_slab indegree;
 615         struct prio_queue queue;
 616         struct commit *commit;
 617         struct author_date_slab author_date;
 618
 619         if (!orig)
 620                 return;
 621         *list = NULL;
 622
 623         init_indegree_slab(&indegree);
 624         memset(&queue, '\0', sizeof(queue));
 625
 626         switch (sort_order) {
 627         default: /* REV_SORT_IN_GRAPH_ORDER */
 628                 queue.compare = NULL;
 629                 break;
 630         case REV_SORT_BY_COMMIT_DATE:
 631                 queue.compare = compare_commits_by_commit_date;
 632                 break;
 633         case REV_SORT_BY_AUTHOR_DATE:
 634                 init_author_date_slab(&author_date);
 635                 queue.compare = compare_commits_by_author_date;
 636                 queue.cb_data = &author_date;
 637                 break;
 638         }
 639
 640         /* Mark them and clear the indegree */
 641         for (next = orig; next; next = next->next) {
 642                 struct commit *commit = next->item;
 643                 *(indegree_slab_at(&indegree, commit)) = 1;
 644                 /* also record the author dates, if needed */
 645                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 646                         record_author_date(&author_date, commit);
 647         }
 648
 649         /* update the indegree */
 650         for (next = orig; next; next = next->next) {
 651                 struct commit_list *parents = next->item->parents;
 652                 while (parents) {
 653                         struct commit *parent = parents->item;
 654                         int *pi = indegree_slab_at(&indegree, parent);
 655
 656                         if (*pi)
 657                                 (*pi)++;
 658                         parents = parents->next;
 659                 }
 660         }
 661
 662         /*
 663          * find the tips
 664          *
 665          * tips are nodes not reachable from any other node in the list
 666          *
 667          * the tips serve as a starting set for the work queue.
 668          */
 669         for (next = orig; next; next = next->next) {
 670                 struct commit *commit = next->item;
 671
 672                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 673                         prio_queue_put(&queue, commit);
 674         }
 675
 676         /*
 677          * This is unfortunate; the initial tips need to be shown
 678          * in the order given from the revision traversal machinery.
 679          */
 680         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 681                 prio_queue_reverse(&queue);
 682
 683         /* We no longer need the commit list */
 684         free_commit_list(orig);
 685
 686         pptr = list;
 687         *list = NULL;
 688         while ((commit = prio_queue_get(&queue)) != NULL) {
 689                 struct commit_list *parents;
 690
 691                 for (parents = commit->parents; parents ; parents = parents->next) {
 692                         struct commit *parent = parents->item;
 693                         int *pi = indegree_slab_at(&indegree, parent);
 694
 695                         if (!*pi)
 696                                 continue;
 697
 698                         /*
 699                          * parents are only enqueued for emission
 700                          * when all their children have been emitted thereby
 701                          * guaranteeing topological order.
 702                          */
 703                         if (--(*pi) == 1)
 704                                 prio_queue_put(&queue, parent);
 705                 }
 706                 /*
 707                  * all children of commit have already been
 708                  * emitted. we can emit it now.
 709                  */
 710                 *(indegree_slab_at(&indegree, commit)) = 0;
 711
 712                 pptr = &commit_list_insert(commit, pptr)->next;
 713         }
 714
 715         clear_indegree_slab(&indegree);
 716         clear_prio_queue(&queue);
 717         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 718                 clear_author_date_slab(&author_date);
 719 }
 720
 721 /* merge-base stuff */
 722
 723 /* Remember to update object flag allocation in object.h */
 724 #define PARENT1         (1u<<16)
 725 #define PARENT2         (1u<<17)
 726 #define STALE           (1u<<18)
 727 #define RESULT          (1u<<19)
 728
 729 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 730
 731 static struct commit *interesting(struct commit_list *list)
 732 {
 733         while (list) {
 734                 struct commit *commit = list->item;
 735                 list = list->next;
 736                 if (commit->object.flags & STALE)
 737                         continue;
 738                 return commit;
 739         }
 740         return NULL;
 741 }
 742
 743 /* all input commits in one and twos[] must have been parsed! */
 744 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 745 {
 746         struct commit_list *list = NULL;
 747         struct commit_list *result = NULL;
 748         int i;
 749
 750         one->object.flags |= PARENT1;
 751         commit_list_insert_by_date(one, &list);
 752         if (!n)
 753                 return list;
 754         for (i = 0; i < n; i++) {
 755                 twos[i]->object.flags |= PARENT2;
 756                 commit_list_insert_by_date(twos[i], &list);
 757         }
 758
 759         while (interesting(list)) {
 760                 struct commit *commit;
 761                 struct commit_list *parents;
 762                 struct commit_list *next;
 763                 int flags;
 764
 765                 commit = list->item;
 766                 next = list->next;
 767                 free(list);
 768                 list = next;
 769
 770                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 771                 if (flags == (PARENT1 | PARENT2)) {
 772                         if (!(commit->object.flags & RESULT)) {
 773                                 commit->object.flags |= RESULT;
 774                                 commit_list_insert_by_date(commit, &result);
 775                         }
 776                         /* Mark parents of a found merge stale */
 777                         flags |= STALE;
 778                 }
 779                 parents = commit->parents;
 780                 while (parents) {
 781                         struct commit *p = parents->item;
 782                         parents = parents->next;
 783                         if ((p->object.flags & flags) == flags)
 784                                 continue;
 785                         if (parse_commit(p))
 786                                 return NULL;
 787                         p->object.flags |= flags;
 788                         commit_list_insert_by_date(p, &list);
 789                 }
 790         }
 791
 792         free_commit_list(list);
 793         return result;
 794 }
 795
 796 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 797 {
 798         struct commit_list *list = NULL;
 799         struct commit_list *result = NULL;
 800         int i;
 801
 802         for (i = 0; i < n; i++) {
 803                 if (one == twos[i])
 804                         /*
 805                          * We do not mark this even with RESULT so we do not
 806                          * have to clean it up.
 807                          */
 808                         return commit_list_insert(one, &result);
 809         }
 810
 811         if (parse_commit(one))
 812                 return NULL;
 813         for (i = 0; i < n; i++) {
 814                 if (parse_commit(twos[i]))
 815                         return NULL;
 816         }
 817
 818         list = paint_down_to_common(one, n, twos);
 819
 820         while (list) {
 821                 struct commit_list *next = list->next;
 822                 if (!(list->item->object.flags & STALE))
 823                         commit_list_insert_by_date(list->item, &result);
 824                 free(list);
 825                 list = next;
 826         }
 827         return result;
 828 }
 829
 830 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 831 {
 832         struct commit_list *i, *j, *k, *ret = NULL;
 833
 834         if (!in)
 835                 return ret;
 836
 837         commit_list_insert(in->item, &ret);
 838
 839         for (i = in->next; i; i = i->next) {
 840                 struct commit_list *new = NULL, *end = NULL;
 841
 842                 for (j = ret; j; j = j->next) {
 843                         struct commit_list *bases;
 844                         bases = get_merge_bases(i->item, j->item, 1);
 845                         if (!new)
 846                                 new = bases;
 847                         else
 848                                 end->next = bases;
 849                         for (k = bases; k; k = k->next)
 850                                 end = k;
 851                 }
 852                 ret = new;
 853         }
 854         return ret;
 855 }
 856
 857 static int remove_redundant(struct commit **array, int cnt)
 858 {
 859         /*
 860          * Some commit in the array may be an ancestor of
 861          * another commit.  Move such commit to the end of
 862          * the array, and return the number of commits that
 863          * are independent from each other.
 864          */
 865         struct commit **work;
 866         unsigned char *redundant;
 867         int *filled_index;
 868         int i, j, filled;
 869
 870         work = xcalloc(cnt, sizeof(*work));
 871         redundant = xcalloc(cnt, 1);
 872         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 873
 874         for (i = 0; i < cnt; i++)
 875                 parse_commit(array[i]);
 876         for (i = 0; i < cnt; i++) {
 877                 struct commit_list *common;
 878
 879                 if (redundant[i])
 880                         continue;
 881                 for (j = filled = 0; j < cnt; j++) {
 882                         if (i == j || redundant[j])
 883                                 continue;
 884                         filled_index[filled] = j;
 885                         work[filled++] = array[j];
 886                 }
 887                 common = paint_down_to_common(array[i], filled, work);
 888                 if (array[i]->object.flags & PARENT2)
 889                         redundant[i] = 1;
 890                 for (j = 0; j < filled; j++)
 891                         if (work[j]->object.flags & PARENT1)
 892                                 redundant[filled_index[j]] = 1;
 893                 clear_commit_marks(array[i], all_flags);
 894                 for (j = 0; j < filled; j++)
 895                         clear_commit_marks(work[j], all_flags);
 896                 free_commit_list(common);
 897         }
 898
 899         /* Now collect the result */
 900         memcpy(work, array, sizeof(*array) * cnt);
 901         for (i = filled = 0; i < cnt; i++)
 902                 if (!redundant[i])
 903                         array[filled++] = work[i];
 904         for (j = filled, i = 0; i < cnt; i++)
 905                 if (redundant[i])
 906                         array[j++] = work[i];
 907         free(work);
 908         free(redundant);
 909         free(filled_index);
 910         return filled;
 911 }
 912
 913 struct commit_list *get_merge_bases_many(struct commit *one,
 914                                          int n,
 915                                          struct commit **twos,
 916                                          int cleanup)
 917 {
 918         struct commit_list *list;
 919         struct commit **rslt;
 920         struct commit_list *result;
 921         int cnt, i;
 922
 923         result = merge_bases_many(one, n, twos);
 924         for (i = 0; i < n; i++) {
 925                 if (one == twos[i])
 926                         return result;
 927         }
 928         if (!result || !result->next) {
 929                 if (cleanup) {
 930                         clear_commit_marks(one, all_flags);
 931                         clear_commit_marks_many(n, twos, all_flags);
 932                 }
 933                 return result;
 934         }
 935
 936         /* There are more than one */
 937         cnt = 0;
 938         list = result;
 939         while (list) {
 940                 list = list->next;
 941                 cnt++;
 942         }
 943         rslt = xcalloc(cnt, sizeof(*rslt));
 944         for (list = result, i = 0; list; list = list->next)
 945                 rslt[i++] = list->item;
 946         free_commit_list(result);
 947
 948         clear_commit_marks(one, all_flags);
 949         clear_commit_marks_many(n, twos, all_flags);
 950
 951         cnt = remove_redundant(rslt, cnt);
 952         result = NULL;
 953         for (i = 0; i < cnt; i++)
 954                 commit_list_insert_by_date(rslt[i], &result);
 955         free(rslt);
 956         return result;
 957 }
 958
 959 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 960                                     int cleanup)
 961 {
 962         return get_merge_bases_many(one, 1, &two, cleanup);
 963 }
 964
 965 /*
 966  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 967  */
 968 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 969 {
 970         if (!with_commit)
 971                 return 1;
 972         while (with_commit) {
 973                 struct commit *other;
 974
 975                 other = with_commit->item;
 976                 with_commit = with_commit->next;
 977                 if (in_merge_bases(other, commit))
 978                         return 1;
 979         }
 980         return 0;
 981 }
 982
 983 /*
 984  * Is "commit" an ancestor of one of the "references"?
 985  */
 986 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 987 {
 988         struct commit_list *bases;
 989         int ret = 0, i;
 990
 991         if (parse_commit(commit))
 992                 return ret;
 993         for (i = 0; i < nr_reference; i++)
 994                 if (parse_commit(reference[i]))
 995                         return ret;
 996
 997         bases = paint_down_to_common(commit, nr_reference, reference);
 998         if (commit->object.flags & PARENT2)
 999                 ret = 1;
1000         clear_commit_marks(commit, all_flags);
1001         clear_commit_marks_many(nr_reference, reference, all_flags);
1002         free_commit_list(bases);
1003         return ret;
1004 }
1005
1006 /*
1007  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1008  */
1009 int in_merge_bases(struct commit *commit, struct commit *reference)
1010 {
1011         return in_merge_bases_many(commit, 1, &reference);
1012 }
1013
1014 struct commit_list *reduce_heads(struct commit_list *heads)
1015 {
1016         struct commit_list *p;
1017         struct commit_list *result = NULL, **tail = &result;
1018         struct commit **array;
1019         int num_head, i;
1020
1021         if (!heads)
1022                 return NULL;
1023
1024         /* Uniquify */
1025         for (p = heads; p; p = p->next)
1026                 p->item->object.flags &= ~STALE;
1027         for (p = heads, num_head = 0; p; p = p->next) {
1028                 if (p->item->object.flags & STALE)
1029                         continue;
1030                 p->item->object.flags |= STALE;
1031                 num_head++;
1032         }
1033         array = xcalloc(num_head, sizeof(*array));
1034         for (p = heads, i = 0; p; p = p->next) {
1035                 if (p->item->object.flags & STALE) {
1036                         array[i++] = p->item;
1037                         p->item->object.flags &= ~STALE;
1038                 }
1039         }
1040         num_head = remove_redundant(array, num_head);
1041         for (i = 0; i < num_head; i++)
1042                 tail = &commit_list_insert(array[i], tail)->next;
1043         return result;
1044 }
1045
1046 static const char gpg_sig_header[] = "gpgsig";
1047 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1048
1049 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1050 {
1051         struct strbuf sig = STRBUF_INIT;
1052         int inspos, copypos;
1053
1054         /* find the end of the header */
1055         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1056
1057         if (!keyid || !*keyid)
1058                 keyid = get_signing_key();
1059         if (sign_buffer(buf, &sig, keyid)) {
1060                 strbuf_release(&sig);
1061                 return -1;
1062         }
1063
1064         for (copypos = 0; sig.buf[copypos]; ) {
1065                 const char *bol = sig.buf + copypos;
1066                 const char *eol = strchrnul(bol, '\n');
1067                 int len = (eol - bol) + !!*eol;
1068
1069                 if (!copypos) {
1070                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1071                         inspos += gpg_sig_header_len;
1072                 }
1073                 strbuf_insert(buf, inspos++, " ", 1);
1074                 strbuf_insert(buf, inspos, bol, len);
1075                 inspos += len;
1076                 copypos += len;
1077         }
1078         strbuf_release(&sig);
1079         return 0;
1080 }
1081
1082 int parse_signed_commit(const unsigned char *sha1,
1083                         struct strbuf *payload, struct strbuf *signature)
1084 {
1085         unsigned long size;
1086         enum object_type type;
1087         char *buffer = read_sha1_file(sha1, &type, &size);
1088         int in_signature, saw_signature = -1;
1089         char *line, *tail;
1090
1091         if (!buffer || type != OBJ_COMMIT)
1092                 goto cleanup;
1093
1094         line = buffer;
1095         tail = buffer + size;
1096         in_signature = 0;
1097         saw_signature = 0;
1098         while (line < tail) {
1099                 const char *sig = NULL;
1100                 char *next = memchr(line, '\n', tail - line);
1101
1102                 next = next ? next + 1 : tail;
1103                 if (in_signature && line[0] == ' ')
1104                         sig = line + 1;
1105                 else if (starts_with(line, gpg_sig_header) &&
1106                          line[gpg_sig_header_len] == ' ')
1107                         sig = line + gpg_sig_header_len + 1;
1108                 if (sig) {
1109                         strbuf_add(signature, sig, next - sig);
1110                         saw_signature = 1;
1111                         in_signature = 1;
1112                 } else {
1113                         if (*line == '\n')
1114                                 /* dump the whole remainder of the buffer */
1115                                 next = tail;
1116                         strbuf_add(payload, line, next - line);
1117                         in_signature = 0;
1118                 }
1119                 line = next;
1120         }
1121  cleanup:
1122         free(buffer);
1123         return saw_signature;
1124 }
1125
1126 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1127 {
1128         struct merge_remote_desc *desc;
1129         struct commit_extra_header *mergetag;
1130         char *buf;
1131         unsigned long size, len;
1132         enum object_type type;
1133
1134         desc = merge_remote_util(parent);
1135         if (!desc || !desc->obj)
1136                 return;
1137         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1138         if (!buf || type != OBJ_TAG)
1139                 goto free_return;
1140         len = parse_signature(buf, size);
1141         if (size == len)
1142                 goto free_return;
1143         /*
1144          * We could verify this signature and either omit the tag when
1145          * it does not validate, but the integrator may not have the
1146          * public key of the signer of the tag he is merging, while a
1147          * later auditor may have it while auditing, so let's not run
1148          * verify-signed-buffer here for now...
1149          *
1150          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1151          *      warn("warning: signed tag unverified.");
1152          */
1153         mergetag = xcalloc(1, sizeof(*mergetag));
1154         mergetag->key = xstrdup("mergetag");
1155         mergetag->value = buf;
1156         mergetag->len = size;
1157
1158         **tail = mergetag;
1159         *tail = &mergetag->next;
1160         return;
1161
1162 free_return:
1163         free(buf);
1164 }
1165
1166 static struct {
1167         char result;
1168         const char *check;
1169 } sigcheck_gpg_status[] = {
1170         { 'G', "\n[GNUPG:] GOODSIG " },
1171         { 'B', "\n[GNUPG:] BADSIG " },
1172         { 'U', "\n[GNUPG:] TRUST_NEVER" },
1173         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1174 };
1175
1176 static void parse_gpg_output(struct signature_check *sigc)
1177 {
1178         const char *buf = sigc->gpg_status;
1179         int i;
1180
1181         /* Iterate over all search strings */
1182         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1183                 const char *found, *next;
1184
1185                 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
1186                         found = strstr(buf, sigcheck_gpg_status[i].check);
1187                         if (!found)
1188                                 continue;
1189                         found += strlen(sigcheck_gpg_status[i].check);
1190                 }
1191                 sigc->result = sigcheck_gpg_status[i].result;
1192                 /* The trust messages are not followed by key/signer information */
1193                 if (sigc->result != 'U') {
1194                         sigc->key = xmemdupz(found, 16);
1195                         found += 17;
1196                         next = strchrnul(found, '\n');
1197                         sigc->signer = xmemdupz(found, next - found);
1198                 }
1199         }
1200 }
1201
1202 void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1203 {
1204         struct strbuf payload = STRBUF_INIT;
1205         struct strbuf signature = STRBUF_INIT;
1206         struct strbuf gpg_output = STRBUF_INIT;
1207         struct strbuf gpg_status = STRBUF_INIT;
1208         int status;
1209
1210         sigc->result = 'N';
1211
1212         if (parse_signed_commit(commit->object.sha1,
1213                                 &payload, &signature) <= 0)
1214                 goto out;
1215         status = verify_signed_buffer(payload.buf, payload.len,
1216                                       signature.buf, signature.len,
1217                                       &gpg_output, &gpg_status);
1218         if (status && !gpg_output.len)
1219                 goto out;
1220         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1221         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1222         parse_gpg_output(sigc);
1223
1224  out:
1225         strbuf_release(&gpg_status);
1226         strbuf_release(&gpg_output);
1227         strbuf_release(&payload);
1228         strbuf_release(&signature);
1229 }
1230
1231
1232
1233 void append_merge_tag_headers(struct commit_list *parents,
1234                               struct commit_extra_header ***tail)
1235 {
1236         while (parents) {
1237                 struct commit *parent = parents->item;
1238                 handle_signed_tag(parent, tail);
1239                 parents = parents->next;
1240         }
1241 }
1242
1243 static void add_extra_header(struct strbuf *buffer,
1244                              struct commit_extra_header *extra)
1245 {
1246         strbuf_addstr(buffer, extra->key);
1247         if (extra->len)
1248                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1249         else
1250                 strbuf_addch(buffer, '\n');
1251 }
1252
1253 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1254                                                       const char **exclude)
1255 {
1256         struct commit_extra_header *extra = NULL;
1257         unsigned long size;
1258         enum object_type type;
1259         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1260         if (buffer && type == OBJ_COMMIT)
1261                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1262         free(buffer);
1263         return extra;
1264 }
1265
1266 static inline int standard_header_field(const char *field, size_t len)
1267 {
1268         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1269                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1270                 (len == 6 && !memcmp(field, "author ", 7)) ||
1271                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1272                 (len == 8 && !memcmp(field, "encoding ", 9)));
1273 }
1274
1275 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1276 {
1277         if (!exclude)
1278                 return 0;
1279
1280         while (*exclude) {
1281                 size_t xlen = strlen(*exclude);
1282                 if (len == xlen &&
1283                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1284                         return 1;
1285                 exclude++;
1286         }
1287         return 0;
1288 }
1289
1290 static struct commit_extra_header *read_commit_extra_header_lines(
1291         const char *buffer, size_t size,
1292         const char **exclude)
1293 {
1294         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1295         const char *line, *next, *eof, *eob;
1296         struct strbuf buf = STRBUF_INIT;
1297
1298         for (line = buffer, eob = line + size;
1299              line < eob && *line != '\n';
1300              line = next) {
1301                 next = memchr(line, '\n', eob - line);
1302                 next = next ? next + 1 : eob;
1303                 if (*line == ' ') {
1304                         /* continuation */
1305                         if (it)
1306                                 strbuf_add(&buf, line + 1, next - (line + 1));
1307                         continue;
1308                 }
1309                 if (it)
1310                         it->value = strbuf_detach(&buf, &it->len);
1311                 strbuf_reset(&buf);
1312                 it = NULL;
1313
1314                 eof = strchr(line, ' ');
1315                 if (next <= eof)
1316                         eof = next;
1317
1318                 if (standard_header_field(line, eof - line) ||
1319                     excluded_header_field(line, eof - line, exclude))
1320                         continue;
1321
1322                 it = xcalloc(1, sizeof(*it));
1323                 it->key = xmemdupz(line, eof-line);
1324                 *tail = it;
1325                 tail = &it->next;
1326                 if (eof + 1 < next)
1327                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1328         }
1329         if (it)
1330                 it->value = strbuf_detach(&buf, &it->len);
1331         return extra;
1332 }
1333
1334 void free_commit_extra_headers(struct commit_extra_header *extra)
1335 {
1336         while (extra) {
1337                 struct commit_extra_header *next = extra->next;
1338                 free(extra->key);
1339                 free(extra->value);
1340                 free(extra);
1341                 extra = next;
1342         }
1343 }
1344
1345 int commit_tree(const struct strbuf *msg, const unsigned char *tree,
1346                 struct commit_list *parents, unsigned char *ret,
1347                 const char *author, const char *sign_commit)
1348 {
1349         struct commit_extra_header *extra = NULL, **tail = &extra;
1350         int result;
1351
1352         append_merge_tag_headers(parents, &tail);
1353         result = commit_tree_extended(msg, tree, parents, ret,
1354                                       author, sign_commit, extra);
1355         free_commit_extra_headers(extra);
1356         return result;
1357 }
1358
1359 static int find_invalid_utf8(const char *buf, int len)
1360 {
1361         int offset = 0;
1362         static const unsigned int max_codepoint[] = {
1363                 0x7f, 0x7ff, 0xffff, 0x10ffff
1364         };
1365
1366         while (len) {
1367                 unsigned char c = *buf++;
1368                 int bytes, bad_offset;
1369                 unsigned int codepoint;
1370                 unsigned int min_val, max_val;
1371
1372                 len--;
1373                 offset++;
1374
1375                 /* Simple US-ASCII? No worries. */
1376                 if (c < 0x80)
1377                         continue;
1378
1379                 bad_offset = offset-1;
1380
1381                 /*
1382                  * Count how many more high bits set: that's how
1383                  * many more bytes this sequence should have.
1384                  */
1385                 bytes = 0;
1386                 while (c & 0x40) {
1387                         c <<= 1;
1388                         bytes++;
1389                 }
1390
1391                 /*
1392                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1393                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1394                  */
1395                 if (bytes < 1 || 3 < bytes)
1396                         return bad_offset;
1397
1398                 /* Do we *have* that many bytes? */
1399                 if (len < bytes)
1400                         return bad_offset;
1401
1402                 /*
1403                  * Place the encoded bits at the bottom of the value and compute the
1404                  * valid range.
1405                  */
1406                 codepoint = (c & 0x7f) >> bytes;
1407                 min_val = max_codepoint[bytes-1] + 1;
1408                 max_val = max_codepoint[bytes];
1409
1410                 offset += bytes;
1411                 len -= bytes;
1412
1413                 /* And verify that they are good continuation bytes */
1414                 do {
1415                         codepoint <<= 6;
1416                         codepoint |= *buf & 0x3f;
1417                         if ((*buf++ & 0xc0) != 0x80)
1418                                 return bad_offset;
1419                 } while (--bytes);
1420
1421                 /* Reject codepoints that are out of range for the sequence length. */
1422                 if (codepoint < min_val || codepoint > max_val)
1423                         return bad_offset;
1424                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1425                 if ((codepoint & 0x1ff800) == 0xd800)
1426                         return bad_offset;
1427                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1428                 if ((codepoint & 0xfffe) == 0xfffe)
1429                         return bad_offset;
1430                 /* So are anything in the range U+FDD0..U+FDEF. */
1431                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1432                         return bad_offset;
1433         }
1434         return -1;
1435 }
1436
1437 /*
1438  * This verifies that the buffer is in proper utf8 format.
1439  *
1440  * If it isn't, it assumes any non-utf8 characters are Latin1,
1441  * and does the conversion.
1442  */
1443 static int verify_utf8(struct strbuf *buf)
1444 {
1445         int ok = 1;
1446         long pos = 0;
1447
1448         for (;;) {
1449                 int bad;
1450                 unsigned char c;
1451                 unsigned char replace[2];
1452
1453                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1454                 if (bad < 0)
1455                         return ok;
1456                 pos += bad;
1457                 ok = 0;
1458                 c = buf->buf[pos];
1459                 strbuf_remove(buf, pos, 1);
1460
1461                 /* We know 'c' must be in the range 128-255 */
1462                 replace[0] = 0xc0 + (c >> 6);
1463                 replace[1] = 0x80 + (c & 0x3f);
1464                 strbuf_insert(buf, pos, replace, 2);
1465                 pos += 2;
1466         }
1467 }
1468
1469 static const char commit_utf8_warn[] =
1470 "Warning: commit message did not conform to UTF-8.\n"
1471 "You may want to amend it after fixing the message, or set the config\n"
1472 "variable i18n.commitencoding to the encoding your project uses.\n";
1473
1474 int commit_tree_extended(const struct strbuf *msg, const unsigned char *tree,
1475                          struct commit_list *parents, unsigned char *ret,
1476                          const char *author, const char *sign_commit,
1477                          struct commit_extra_header *extra)
1478 {
1479         int result;
1480         int encoding_is_utf8;
1481         struct strbuf buffer;
1482
1483         assert_sha1_type(tree, OBJ_TREE);
1484
1485         if (memchr(msg->buf, '\0', msg->len))
1486                 return error("a NUL byte in commit log message not allowed.");
1487
1488         /* Not having i18n.commitencoding is the same as having utf-8 */
1489         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1490
1491         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1492         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1493
1494         /*
1495          * NOTE! This ordering means that the same exact tree merged with a
1496          * different order of parents will be a _different_ changeset even
1497          * if everything else stays the same.
1498          */
1499         while (parents) {
1500                 struct commit_list *next = parents->next;
1501                 struct commit *parent = parents->item;
1502
1503                 strbuf_addf(&buffer, "parent %s\n",
1504                             sha1_to_hex(parent->object.sha1));
1505                 free(parents);
1506                 parents = next;
1507         }
1508
1509         /* Person/date information */
1510         if (!author)
1511                 author = git_author_info(IDENT_STRICT);
1512         strbuf_addf(&buffer, "author %s\n", author);
1513         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1514         if (!encoding_is_utf8)
1515                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1516
1517         while (extra) {
1518                 add_extra_header(&buffer, extra);
1519                 extra = extra->next;
1520         }
1521         strbuf_addch(&buffer, '\n');
1522
1523         /* And add the comment */
1524         strbuf_addbuf(&buffer, msg);
1525
1526         /* And check the encoding */
1527         if (encoding_is_utf8 && !verify_utf8(&buffer))
1528                 fprintf(stderr, commit_utf8_warn);
1529
1530         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1531                 return -1;
1532
1533         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1534         strbuf_release(&buffer);
1535         return result;
1536 }
1537
1538 struct commit *get_merge_parent(const char *name)
1539 {
1540         struct object *obj;
1541         struct commit *commit;
1542         unsigned char sha1[20];
1543         if (get_sha1(name, sha1))
1544                 return NULL;
1545         obj = parse_object(sha1);
1546         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1547         if (commit && !commit->util) {
1548                 struct merge_remote_desc *desc;
1549                 desc = xmalloc(sizeof(*desc));
1550                 desc->obj = obj;
1551                 desc->name = strdup(name);
1552                 commit->util = desc;
1553         }
1554         return commit;
1555 }
1556
1557 /*
1558  * Append a commit to the end of the commit_list.
1559  *
1560  * next starts by pointing to the variable that holds the head of an
1561  * empty commit_list, and is updated to point to the "next" field of
1562  * the last item on the list as new commits are appended.
1563  *
1564  * Usage example:
1565  *
1566  *     struct commit_list *list;
1567  *     struct commit_list **next = &list;
1568  *
1569  *     next = commit_list_append(c1, next);
1570  *     next = commit_list_append(c2, next);
1571  *     assert(commit_list_count(list) == 2);
1572  *     return list;
1573  */
1574 struct commit_list **commit_list_append(struct commit *commit,
1575                                         struct commit_list **next)
1576 {
1577         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1578         new->item = commit;
1579         *next = new;
1580         new->next = NULL;
1581         return &new->next;
1582 }
1583
1584 void print_commit_list(struct commit_list *list,
1585                        const char *format_cur,
1586                        const char *format_last)
1587 {
1588         for ( ; list; list = list->next) {
1589                 const char *format = list->next ? format_cur : format_last;
1590                 printf(format, sha1_to_hex(list->item->object.sha1));
1591         }
1592 }