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
  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                 return create_object(sha1, OBJ_COMMIT, c);
  67         }
  68         if (!obj->type)
  69                 obj->type = OBJ_COMMIT;
  70         return check_commit(obj, sha1, 0);
  71 }
  72
  73 struct commit *lookup_commit_reference_by_name(const char *name)
  74 {
  75         unsigned char sha1[20];
  76         struct commit *commit;
  77
  78         if (get_sha1_committish(name, sha1))
  79                 return NULL;
  80         commit = lookup_commit_reference(sha1);
  81         if (parse_commit(commit))
  82                 return NULL;
  83         return commit;
  84 }
  85
  86 static unsigned long parse_commit_date(const char *buf, const char *tail)
  87 {
  88         const char *dateptr;
  89
  90         if (buf + 6 >= tail)
  91                 return 0;
  92         if (memcmp(buf, "author", 6))
  93                 return 0;
  94         while (buf < tail && *buf++ != '\n')
  95                 /* nada */;
  96         if (buf + 9 >= tail)
  97                 return 0;
  98         if (memcmp(buf, "committer", 9))
  99                 return 0;
 100         while (buf < tail && *buf++ != '>')
 101                 /* nada */;
 102         if (buf >= tail)
 103                 return 0;
 104         dateptr = buf;
 105         while (buf < tail && *buf++ != '\n')
 106                 /* nada */;
 107         if (buf >= tail)
 108                 return 0;
 109         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 110         return strtoul(dateptr, NULL, 10);
 111 }
 112
 113 static struct commit_graft **commit_graft;
 114 static int commit_graft_alloc, commit_graft_nr;
 115
 116 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 117 {
 118         struct commit_graft **commit_graft_table = table;
 119         return commit_graft_table[index]->sha1;
 120 }
 121
 122 static int commit_graft_pos(const unsigned char *sha1)
 123 {
 124         return sha1_pos(sha1, commit_graft, commit_graft_nr,
 125                         commit_graft_sha1_access);
 126 }
 127
 128 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 129 {
 130         int pos = commit_graft_pos(graft->sha1);
 131
 132         if (0 <= pos) {
 133                 if (ignore_dups)
 134                         free(graft);
 135                 else {
 136                         free(commit_graft[pos]);
 137                         commit_graft[pos] = graft;
 138                 }
 139                 return 1;
 140         }
 141         pos = -pos - 1;
 142         ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 143         commit_graft_nr++;
 144         if (pos < commit_graft_nr)
 145                 memmove(commit_graft + pos + 1,
 146                         commit_graft + pos,
 147                         (commit_graft_nr - pos - 1) *
 148                         sizeof(*commit_graft));
 149         commit_graft[pos] = graft;
 150         return 0;
 151 }
 152
 153 struct commit_graft *read_graft_line(char *buf, int len)
 154 {
 155         /* The format is just "Commit Parent1 Parent2 ...\n" */
 156         int i;
 157         struct commit_graft *graft = NULL;
 158
 159         while (len && isspace(buf[len-1]))
 160                 buf[--len] = '\0';
 161         if (buf[0] == '#' || buf[0] == '\0')
 162                 return NULL;
 163         if ((len + 1) % 41)
 164                 goto bad_graft_data;
 165         i = (len + 1) / 41 - 1;
 166         graft = xmalloc(sizeof(*graft) + 20 * i);
 167         graft->nr_parent = i;
 168         if (get_sha1_hex(buf, graft->sha1))
 169                 goto bad_graft_data;
 170         for (i = 40; i < len; i += 41) {
 171                 if (buf[i] != ' ')
 172                         goto bad_graft_data;
 173                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 174                         goto bad_graft_data;
 175         }
 176         return graft;
 177
 178 bad_graft_data:
 179         error("bad graft data: %s", buf);
 180         free(graft);
 181         return NULL;
 182 }
 183
 184 static int read_graft_file(const char *graft_file)
 185 {
 186         FILE *fp = fopen(graft_file, "r");
 187         struct strbuf buf = STRBUF_INIT;
 188         if (!fp)
 189                 return -1;
 190         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 191                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 192                 struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 193                 if (!graft)
 194                         continue;
 195                 if (register_commit_graft(graft, 1))
 196                         error("duplicate graft data: %s", buf.buf);
 197         }
 198         fclose(fp);
 199         strbuf_release(&buf);
 200         return 0;
 201 }
 202
 203 static void prepare_commit_graft(void)
 204 {
 205         static int commit_graft_prepared;
 206         char *graft_file;
 207
 208         if (commit_graft_prepared)
 209                 return;
 210         graft_file = get_graft_file();
 211         read_graft_file(graft_file);
 212         /* make sure shallows are read */
 213         is_repository_shallow();
 214         commit_graft_prepared = 1;
 215 }
 216
 217 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 218 {
 219         int pos;
 220         prepare_commit_graft();
 221         pos = commit_graft_pos(sha1);
 222         if (pos < 0)
 223                 return NULL;
 224         return commit_graft[pos];
 225 }
 226
 227 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 228 {
 229         int i, ret;
 230         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 231                 ret = fn(commit_graft[i], cb_data);
 232         return ret;
 233 }
 234
 235 int unregister_shallow(const unsigned char *sha1)
 236 {
 237         int pos = commit_graft_pos(sha1);
 238         if (pos < 0)
 239                 return -1;
 240         if (pos + 1 < commit_graft_nr)
 241                 memmove(commit_graft + pos, commit_graft + pos + 1,
 242                                 sizeof(struct commit_graft *)
 243                                 * (commit_graft_nr - pos - 1));
 244         commit_graft_nr--;
 245         return 0;
 246 }
 247
 248 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 249 {
 250         const char *tail = buffer;
 251         const char *bufptr = buffer;
 252         unsigned char parent[20];
 253         struct commit_list **pptr;
 254         struct commit_graft *graft;
 255
 256         if (item->object.parsed)
 257                 return 0;
 258         item->object.parsed = 1;
 259         tail += size;
 260         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 261                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 262         if (get_sha1_hex(bufptr + 5, parent) < 0)
 263                 return error("bad tree pointer in commit %s",
 264                              sha1_to_hex(item->object.sha1));
 265         item->tree = lookup_tree(parent);
 266         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 267         pptr = &item->parents;
 268
 269         graft = lookup_commit_graft(item->object.sha1);
 270         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 271                 struct commit *new_parent;
 272
 273                 if (tail <= bufptr + 48 ||
 274                     get_sha1_hex(bufptr + 7, parent) ||
 275                     bufptr[47] != '\n')
 276                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 277                 bufptr += 48;
 278                 /*
 279                  * The clone is shallow if nr_parent < 0, and we must
 280                  * not traverse its real parents even when we unhide them.
 281                  */
 282                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 283                         continue;
 284                 new_parent = lookup_commit(parent);
 285                 if (new_parent)
 286                         pptr = &commit_list_insert(new_parent, pptr)->next;
 287         }
 288         if (graft) {
 289                 int i;
 290                 struct commit *new_parent;
 291                 for (i = 0; i < graft->nr_parent; i++) {
 292                         new_parent = lookup_commit(graft->parent[i]);
 293                         if (!new_parent)
 294                                 continue;
 295                         pptr = &commit_list_insert(new_parent, pptr)->next;
 296                 }
 297         }
 298         item->date = parse_commit_date(bufptr, tail);
 299
 300         return 0;
 301 }
 302
 303 int parse_commit(struct commit *item)
 304 {
 305         enum object_type type;
 306         void *buffer;
 307         unsigned long size;
 308         int ret;
 309
 310         if (!item)
 311                 return -1;
 312         if (item->object.parsed)
 313                 return 0;
 314         buffer = read_sha1_file(item->object.sha1, &type, &size);
 315         if (!buffer)
 316                 return error("Could not read %s",
 317                              sha1_to_hex(item->object.sha1));
 318         if (type != OBJ_COMMIT) {
 319                 free(buffer);
 320                 return error("Object %s not a commit",
 321                              sha1_to_hex(item->object.sha1));
 322         }
 323         ret = parse_commit_buffer(item, buffer, size);
 324         if (save_commit_buffer && !ret) {
 325                 item->buffer = buffer;
 326                 return 0;
 327         }
 328         free(buffer);
 329         return ret;
 330 }
 331
 332 void parse_commit_or_die(struct commit *item)
 333 {
 334         if (parse_commit(item))
 335                 die("unable to parse commit %s",
 336                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 337 }
 338
 339 int find_commit_subject(const char *commit_buffer, const char **subject)
 340 {
 341         const char *eol;
 342         const char *p = commit_buffer;
 343
 344         while (*p && (*p != '\n' || p[1] != '\n'))
 345                 p++;
 346         if (*p) {
 347                 p += 2;
 348                 for (eol = p; *eol && *eol != '\n'; eol++)
 349                         ; /* do nothing */
 350         } else
 351                 eol = p;
 352
 353         *subject = p;
 354
 355         return eol - p;
 356 }
 357
 358 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 359 {
 360         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 361         new_list->item = item;
 362         new_list->next = *list_p;
 363         *list_p = new_list;
 364         return new_list;
 365 }
 366
 367 unsigned commit_list_count(const struct commit_list *l)
 368 {
 369         unsigned c = 0;
 370         for (; l; l = l->next )
 371                 c++;
 372         return c;
 373 }
 374
 375 struct commit_list *copy_commit_list(struct commit_list *list)
 376 {
 377         struct commit_list *head = NULL;
 378         struct commit_list **pp = &head;
 379         while (list) {
 380                 struct commit_list *new;
 381                 new = xmalloc(sizeof(struct commit_list));
 382                 new->item = list->item;
 383                 new->next = NULL;
 384                 *pp = new;
 385                 pp = &new->next;
 386                 list = list->next;
 387         }
 388         return head;
 389 }
 390
 391 void free_commit_list(struct commit_list *list)
 392 {
 393         while (list) {
 394                 struct commit_list *temp = list;
 395                 list = temp->next;
 396                 free(temp);
 397         }
 398 }
 399
 400 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 401 {
 402         struct commit_list **pp = list;
 403         struct commit_list *p;
 404         while ((p = *pp) != NULL) {
 405                 if (p->item->date < item->date) {
 406                         break;
 407                 }
 408                 pp = &p->next;
 409         }
 410         return commit_list_insert(item, pp);
 411 }
 412
 413 static int commit_list_compare_by_date(const void *a, const void *b)
 414 {
 415         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 416         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 417         if (a_date < b_date)
 418                 return 1;
 419         if (a_date > b_date)
 420                 return -1;
 421         return 0;
 422 }
 423
 424 static void *commit_list_get_next(const void *a)
 425 {
 426         return ((const struct commit_list *)a)->next;
 427 }
 428
 429 static void commit_list_set_next(void *a, void *next)
 430 {
 431         ((struct commit_list *)a)->next = next;
 432 }
 433
 434 void commit_list_sort_by_date(struct commit_list **list)
 435 {
 436         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 437                                 commit_list_compare_by_date);
 438 }
 439
 440 struct commit *pop_most_recent_commit(struct commit_list **list,
 441                                       unsigned int mark)
 442 {
 443         struct commit *ret = (*list)->item;
 444         struct commit_list *parents = ret->parents;
 445         struct commit_list *old = *list;
 446
 447         *list = (*list)->next;
 448         free(old);
 449
 450         while (parents) {
 451                 struct commit *commit = parents->item;
 452                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 453                         commit->object.flags |= mark;
 454                         commit_list_insert_by_date(commit, list);
 455                 }
 456                 parents = parents->next;
 457         }
 458         return ret;
 459 }
 460
 461 static void clear_commit_marks_1(struct commit_list **plist,
 462                                  struct commit *commit, unsigned int mark)
 463 {
 464         while (commit) {
 465                 struct commit_list *parents;
 466
 467                 if (!(mark & commit->object.flags))
 468                         return;
 469
 470                 commit->object.flags &= ~mark;
 471
 472                 parents = commit->parents;
 473                 if (!parents)
 474                         return;
 475
 476                 while ((parents = parents->next))
 477                         commit_list_insert(parents->item, plist);
 478
 479                 commit = commit->parents->item;
 480         }
 481 }
 482
 483 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 484 {
 485         struct commit_list *list = NULL;
 486
 487         while (nr--) {
 488                 commit_list_insert(*commit, &list);
 489                 commit++;
 490         }
 491         while (list)
 492                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 493 }
 494
 495 void clear_commit_marks(struct commit *commit, unsigned int mark)
 496 {
 497         clear_commit_marks_many(1, &commit, mark);
 498 }
 499
 500 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 501 {
 502         struct object *object;
 503         struct commit *commit;
 504         unsigned int i;
 505
 506         for (i = 0; i < a->nr; i++) {
 507                 object = a->objects[i].item;
 508                 commit = lookup_commit_reference_gently(object->sha1, 1);
 509                 if (commit)
 510                         clear_commit_marks(commit, mark);
 511         }
 512 }
 513
 514 struct commit *pop_commit(struct commit_list **stack)
 515 {
 516         struct commit_list *top = *stack;
 517         struct commit *item = top ? top->item : NULL;
 518
 519         if (top) {
 520                 *stack = top->next;
 521                 free(top);
 522         }
 523         return item;
 524 }
 525
 526 /*
 527  * Topological sort support
 528  */
 529
 530 /* count number of children that have not been emitted */
 531 define_commit_slab(indegree_slab, int);
 532
 533 /* record author-date for each commit object */
 534 define_commit_slab(author_date_slab, unsigned long);
 535
 536 static void record_author_date(struct author_date_slab *author_date,
 537                                struct commit *commit)
 538 {
 539         const char *buf, *line_end, *ident_line;
 540         char *buffer = NULL;
 541         struct ident_split ident;
 542         char *date_end;
 543         unsigned long date;
 544
 545         if (!commit->buffer) {
 546                 unsigned long size;
 547                 enum object_type type;
 548                 buffer = read_sha1_file(commit->object.sha1, &type, &size);
 549                 if (!buffer)
 550                         return;
 551         }
 552
 553         for (buf = commit->buffer ? commit->buffer : buffer;
 554              buf;
 555              buf = line_end + 1) {
 556                 line_end = strchrnul(buf, '\n');
 557                 ident_line = skip_prefix(buf, "author ");
 558                 if (!ident_line) {
 559                         if (!line_end[0] || line_end[1] == '\n')
 560                                 return; /* end of header */
 561                         continue;
 562                 }
 563                 if (split_ident_line(&ident,
 564                                      ident_line, line_end - ident_line) ||
 565                     !ident.date_begin || !ident.date_end)
 566                         goto fail_exit; /* malformed "author" line */
 567                 break;
 568         }
 569
 570         date = strtoul(ident.date_begin, &date_end, 10);
 571         if (date_end != ident.date_end)
 572                 goto fail_exit; /* malformed date */
 573         *(author_date_slab_at(author_date, commit)) = date;
 574
 575 fail_exit:
 576         free(buffer);
 577 }
 578
 579 static int compare_commits_by_author_date(const void *a_, const void *b_,
 580                                           void *cb_data)
 581 {
 582         const struct commit *a = a_, *b = b_;
 583         struct author_date_slab *author_date = cb_data;
 584         unsigned long a_date = *(author_date_slab_at(author_date, a));
 585         unsigned long b_date = *(author_date_slab_at(author_date, b));
 586
 587         /* newer commits with larger date first */
 588         if (a_date < b_date)
 589                 return 1;
 590         else if (a_date > b_date)
 591                 return -1;
 592         return 0;
 593 }
 594
 595 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 596 {
 597         const struct commit *a = a_, *b = b_;
 598         /* newer commits with larger date first */
 599         if (a->date < b->date)
 600                 return 1;
 601         else if (a->date > b->date)
 602                 return -1;
 603         return 0;
 604 }
 605
 606 /*
 607  * Performs an in-place topological sort on the list supplied.
 608  */
 609 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 610 {
 611         struct commit_list *next, *orig = *list;
 612         struct commit_list **pptr;
 613         struct indegree_slab indegree;
 614         struct prio_queue queue;
 615         struct commit *commit;
 616         struct author_date_slab author_date;
 617
 618         if (!orig)
 619                 return;
 620         *list = NULL;
 621
 622         init_indegree_slab(&indegree);
 623         memset(&queue, '\0', sizeof(queue));
 624
 625         switch (sort_order) {
 626         default: /* REV_SORT_IN_GRAPH_ORDER */
 627                 queue.compare = NULL;
 628                 break;
 629         case REV_SORT_BY_COMMIT_DATE:
 630                 queue.compare = compare_commits_by_commit_date;
 631                 break;
 632         case REV_SORT_BY_AUTHOR_DATE:
 633                 init_author_date_slab(&author_date);
 634                 queue.compare = compare_commits_by_author_date;
 635                 queue.cb_data = &author_date;
 636                 break;
 637         }
 638
 639         /* Mark them and clear the indegree */
 640         for (next = orig; next; next = next->next) {
 641                 struct commit *commit = next->item;
 642                 *(indegree_slab_at(&indegree, commit)) = 1;
 643                 /* also record the author dates, if needed */
 644                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 645                         record_author_date(&author_date, commit);
 646         }
 647
 648         /* update the indegree */
 649         for (next = orig; next; next = next->next) {
 650                 struct commit_list *parents = next->item->parents;
 651                 while (parents) {
 652                         struct commit *parent = parents->item;
 653                         int *pi = indegree_slab_at(&indegree, parent);
 654
 655                         if (*pi)
 656                                 (*pi)++;
 657                         parents = parents->next;
 658                 }
 659         }
 660
 661         /*
 662          * find the tips
 663          *
 664          * tips are nodes not reachable from any other node in the list
 665          *
 666          * the tips serve as a starting set for the work queue.
 667          */
 668         for (next = orig; next; next = next->next) {
 669                 struct commit *commit = next->item;
 670
 671                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 672                         prio_queue_put(&queue, commit);
 673         }
 674
 675         /*
 676          * This is unfortunate; the initial tips need to be shown
 677          * in the order given from the revision traversal machinery.
 678          */
 679         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 680                 prio_queue_reverse(&queue);
 681
 682         /* We no longer need the commit list */
 683         free_commit_list(orig);
 684
 685         pptr = list;
 686         *list = NULL;
 687         while ((commit = prio_queue_get(&queue)) != NULL) {
 688                 struct commit_list *parents;
 689
 690                 for (parents = commit->parents; parents ; parents = parents->next) {
 691                         struct commit *parent = parents->item;
 692                         int *pi = indegree_slab_at(&indegree, parent);
 693
 694                         if (!*pi)
 695                                 continue;
 696
 697                         /*
 698                          * parents are only enqueued for emission
 699                          * when all their children have been emitted thereby
 700                          * guaranteeing topological order.
 701                          */
 702                         if (--(*pi) == 1)
 703                                 prio_queue_put(&queue, parent);
 704                 }
 705                 /*
 706                  * all children of commit have already been
 707                  * emitted. we can emit it now.
 708                  */
 709                 *(indegree_slab_at(&indegree, commit)) = 0;
 710
 711                 pptr = &commit_list_insert(commit, pptr)->next;
 712         }
 713
 714         clear_indegree_slab(&indegree);
 715         clear_prio_queue(&queue);
 716         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 717                 clear_author_date_slab(&author_date);
 718 }
 719
 720 /* merge-base stuff */
 721
 722 /* Remember to update object flag allocation in object.h */
 723 #define PARENT1         (1u<<16)
 724 #define PARENT2         (1u<<17)
 725 #define STALE           (1u<<18)
 726 #define RESULT          (1u<<19)
 727
 728 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 729
 730 static struct commit *interesting(struct commit_list *list)
 731 {
 732         while (list) {
 733                 struct commit *commit = list->item;
 734                 list = list->next;
 735                 if (commit->object.flags & STALE)
 736                         continue;
 737                 return commit;
 738         }
 739         return NULL;
 740 }
 741
 742 /* all input commits in one and twos[] must have been parsed! */
 743 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 744 {
 745         struct commit_list *list = NULL;
 746         struct commit_list *result = NULL;
 747         int i;
 748
 749         one->object.flags |= PARENT1;
 750         commit_list_insert_by_date(one, &list);
 751         if (!n)
 752                 return list;
 753         for (i = 0; i < n; i++) {
 754                 twos[i]->object.flags |= PARENT2;
 755                 commit_list_insert_by_date(twos[i], &list);
 756         }
 757
 758         while (interesting(list)) {
 759                 struct commit *commit;
 760                 struct commit_list *parents;
 761                 struct commit_list *next;
 762                 int flags;
 763
 764                 commit = list->item;
 765                 next = list->next;
 766                 free(list);
 767                 list = next;
 768
 769                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 770                 if (flags == (PARENT1 | PARENT2)) {
 771                         if (!(commit->object.flags & RESULT)) {
 772                                 commit->object.flags |= RESULT;
 773                                 commit_list_insert_by_date(commit, &result);
 774                         }
 775                         /* Mark parents of a found merge stale */
 776                         flags |= STALE;
 777                 }
 778                 parents = commit->parents;
 779                 while (parents) {
 780                         struct commit *p = parents->item;
 781                         parents = parents->next;
 782                         if ((p->object.flags & flags) == flags)
 783                                 continue;
 784                         if (parse_commit(p))
 785                                 return NULL;
 786                         p->object.flags |= flags;
 787                         commit_list_insert_by_date(p, &list);
 788                 }
 789         }
 790
 791         free_commit_list(list);
 792         return result;
 793 }
 794
 795 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 796 {
 797         struct commit_list *list = NULL;
 798         struct commit_list *result = NULL;
 799         int i;
 800
 801         for (i = 0; i < n; i++) {
 802                 if (one == twos[i])
 803                         /*
 804                          * We do not mark this even with RESULT so we do not
 805                          * have to clean it up.
 806                          */
 807                         return commit_list_insert(one, &result);
 808         }
 809
 810         if (parse_commit(one))
 811                 return NULL;
 812         for (i = 0; i < n; i++) {
 813                 if (parse_commit(twos[i]))
 814                         return NULL;
 815         }
 816
 817         list = paint_down_to_common(one, n, twos);
 818
 819         while (list) {
 820                 struct commit_list *next = list->next;
 821                 if (!(list->item->object.flags & STALE))
 822                         commit_list_insert_by_date(list->item, &result);
 823                 free(list);
 824                 list = next;
 825         }
 826         return result;
 827 }
 828
 829 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 830 {
 831         struct commit_list *i, *j, *k, *ret = NULL;
 832
 833         if (!in)
 834                 return ret;
 835
 836         commit_list_insert(in->item, &ret);
 837
 838         for (i = in->next; i; i = i->next) {
 839                 struct commit_list *new = NULL, *end = NULL;
 840
 841                 for (j = ret; j; j = j->next) {
 842                         struct commit_list *bases;
 843                         bases = get_merge_bases(i->item, j->item, 1);
 844                         if (!new)
 845                                 new = bases;
 846                         else
 847                                 end->next = bases;
 848                         for (k = bases; k; k = k->next)
 849                                 end = k;
 850                 }
 851                 ret = new;
 852         }
 853         return ret;
 854 }
 855
 856 static int remove_redundant(struct commit **array, int cnt)
 857 {
 858         /*
 859          * Some commit in the array may be an ancestor of
 860          * another commit.  Move such commit to the end of
 861          * the array, and return the number of commits that
 862          * are independent from each other.
 863          */
 864         struct commit **work;
 865         unsigned char *redundant;
 866         int *filled_index;
 867         int i, j, filled;
 868
 869         work = xcalloc(cnt, sizeof(*work));
 870         redundant = xcalloc(cnt, 1);
 871         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 872
 873         for (i = 0; i < cnt; i++)
 874                 parse_commit(array[i]);
 875         for (i = 0; i < cnt; i++) {
 876                 struct commit_list *common;
 877
 878                 if (redundant[i])
 879                         continue;
 880                 for (j = filled = 0; j < cnt; j++) {
 881                         if (i == j || redundant[j])
 882                                 continue;
 883                         filled_index[filled] = j;
 884                         work[filled++] = array[j];
 885                 }
 886                 common = paint_down_to_common(array[i], filled, work);
 887                 if (array[i]->object.flags & PARENT2)
 888                         redundant[i] = 1;
 889                 for (j = 0; j < filled; j++)
 890                         if (work[j]->object.flags & PARENT1)
 891                                 redundant[filled_index[j]] = 1;
 892                 clear_commit_marks(array[i], all_flags);
 893                 for (j = 0; j < filled; j++)
 894                         clear_commit_marks(work[j], all_flags);
 895                 free_commit_list(common);
 896         }
 897
 898         /* Now collect the result */
 899         memcpy(work, array, sizeof(*array) * cnt);
 900         for (i = filled = 0; i < cnt; i++)
 901                 if (!redundant[i])
 902                         array[filled++] = work[i];
 903         for (j = filled, i = 0; i < cnt; i++)
 904                 if (redundant[i])
 905                         array[j++] = work[i];
 906         free(work);
 907         free(redundant);
 908         free(filled_index);
 909         return filled;
 910 }
 911
 912 struct commit_list *get_merge_bases_many(struct commit *one,
 913                                          int n,
 914                                          struct commit **twos,
 915                                          int cleanup)
 916 {
 917         struct commit_list *list;
 918         struct commit **rslt;
 919         struct commit_list *result;
 920         int cnt, i;
 921
 922         result = merge_bases_many(one, n, twos);
 923         for (i = 0; i < n; i++) {
 924                 if (one == twos[i])
 925                         return result;
 926         }
 927         if (!result || !result->next) {
 928                 if (cleanup) {
 929                         clear_commit_marks(one, all_flags);
 930                         clear_commit_marks_many(n, twos, all_flags);
 931                 }
 932                 return result;
 933         }
 934
 935         /* There are more than one */
 936         cnt = 0;
 937         list = result;
 938         while (list) {
 939                 list = list->next;
 940                 cnt++;
 941         }
 942         rslt = xcalloc(cnt, sizeof(*rslt));
 943         for (list = result, i = 0; list; list = list->next)
 944                 rslt[i++] = list->item;
 945         free_commit_list(result);
 946
 947         clear_commit_marks(one, all_flags);
 948         clear_commit_marks_many(n, twos, all_flags);
 949
 950         cnt = remove_redundant(rslt, cnt);
 951         result = NULL;
 952         for (i = 0; i < cnt; i++)
 953                 commit_list_insert_by_date(rslt[i], &result);
 954         free(rslt);
 955         return result;
 956 }
 957
 958 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 959                                     int cleanup)
 960 {
 961         return get_merge_bases_many(one, 1, &two, cleanup);
 962 }
 963
 964 /*
 965  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 966  */
 967 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 968 {
 969         if (!with_commit)
 970                 return 1;
 971         while (with_commit) {
 972                 struct commit *other;
 973
 974                 other = with_commit->item;
 975                 with_commit = with_commit->next;
 976                 if (in_merge_bases(other, commit))
 977                         return 1;
 978         }
 979         return 0;
 980 }
 981
 982 /*
 983  * Is "commit" an ancestor of one of the "references"?
 984  */
 985 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 986 {
 987         struct commit_list *bases;
 988         int ret = 0, i;
 989
 990         if (parse_commit(commit))
 991                 return ret;
 992         for (i = 0; i < nr_reference; i++)
 993                 if (parse_commit(reference[i]))
 994                         return ret;
 995
 996         bases = paint_down_to_common(commit, nr_reference, reference);
 997         if (commit->object.flags & PARENT2)
 998                 ret = 1;
 999         clear_commit_marks(commit, all_flags);
1000         clear_commit_marks_many(nr_reference, reference, all_flags);
1001         free_commit_list(bases);
1002         return ret;
1003 }
1004
1005 /*
1006  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1007  */
1008 int in_merge_bases(struct commit *commit, struct commit *reference)
1009 {
1010         return in_merge_bases_many(commit, 1, &reference);
1011 }
1012
1013 struct commit_list *reduce_heads(struct commit_list *heads)
1014 {
1015         struct commit_list *p;
1016         struct commit_list *result = NULL, **tail = &result;
1017         struct commit **array;
1018         int num_head, i;
1019
1020         if (!heads)
1021                 return NULL;
1022
1023         /* Uniquify */
1024         for (p = heads; p; p = p->next)
1025                 p->item->object.flags &= ~STALE;
1026         for (p = heads, num_head = 0; p; p = p->next) {
1027                 if (p->item->object.flags & STALE)
1028                         continue;
1029                 p->item->object.flags |= STALE;
1030                 num_head++;
1031         }
1032         array = xcalloc(sizeof(*array), num_head);
1033         for (p = heads, i = 0; p; p = p->next) {
1034                 if (p->item->object.flags & STALE) {
1035                         array[i++] = p->item;
1036                         p->item->object.flags &= ~STALE;
1037                 }
1038         }
1039         num_head = remove_redundant(array, num_head);
1040         for (i = 0; i < num_head; i++)
1041                 tail = &commit_list_insert(array[i], tail)->next;
1042         return result;
1043 }
1044
1045 static const char gpg_sig_header[] = "gpgsig";
1046 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1047
1048 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1049 {
1050         struct strbuf sig = STRBUF_INIT;
1051         int inspos, copypos;
1052
1053         /* find the end of the header */
1054         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1055
1056         if (!keyid || !*keyid)
1057                 keyid = get_signing_key();
1058         if (sign_buffer(buf, &sig, keyid)) {
1059                 strbuf_release(&sig);
1060                 return -1;
1061         }
1062
1063         for (copypos = 0; sig.buf[copypos]; ) {
1064                 const char *bol = sig.buf + copypos;
1065                 const char *eol = strchrnul(bol, '\n');
1066                 int len = (eol - bol) + !!*eol;
1067
1068                 if (!copypos) {
1069                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1070                         inspos += gpg_sig_header_len;
1071                 }
1072                 strbuf_insert(buf, inspos++, " ", 1);
1073                 strbuf_insert(buf, inspos, bol, len);
1074                 inspos += len;
1075                 copypos += len;
1076         }
1077         strbuf_release(&sig);
1078         return 0;
1079 }
1080
1081 int parse_signed_commit(const unsigned char *sha1,
1082                         struct strbuf *payload, struct strbuf *signature)
1083 {
1084         unsigned long size;
1085         enum object_type type;
1086         char *buffer = read_sha1_file(sha1, &type, &size);
1087         int in_signature, saw_signature = -1;
1088         char *line, *tail;
1089
1090         if (!buffer || type != OBJ_COMMIT)
1091                 goto cleanup;
1092
1093         line = buffer;
1094         tail = buffer + size;
1095         in_signature = 0;
1096         saw_signature = 0;
1097         while (line < tail) {
1098                 const char *sig = NULL;
1099                 char *next = memchr(line, '\n', tail - line);
1100
1101                 next = next ? next + 1 : tail;
1102                 if (in_signature && line[0] == ' ')
1103                         sig = line + 1;
1104                 else if (starts_with(line, gpg_sig_header) &&
1105                          line[gpg_sig_header_len] == ' ')
1106                         sig = line + gpg_sig_header_len + 1;
1107                 if (sig) {
1108                         strbuf_add(signature, sig, next - sig);
1109                         saw_signature = 1;
1110                         in_signature = 1;
1111                 } else {
1112                         if (*line == '\n')
1113                                 /* dump the whole remainder of the buffer */
1114                                 next = tail;
1115                         strbuf_add(payload, line, next - line);
1116                         in_signature = 0;
1117                 }
1118                 line = next;
1119         }
1120  cleanup:
1121         free(buffer);
1122         return saw_signature;
1123 }
1124
1125 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1126 {
1127         struct merge_remote_desc *desc;
1128         struct commit_extra_header *mergetag;
1129         char *buf;
1130         unsigned long size, len;
1131         enum object_type type;
1132
1133         desc = merge_remote_util(parent);
1134         if (!desc || !desc->obj)
1135                 return;
1136         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1137         if (!buf || type != OBJ_TAG)
1138                 goto free_return;
1139         len = parse_signature(buf, size);
1140         if (size == len)
1141                 goto free_return;
1142         /*
1143          * We could verify this signature and either omit the tag when
1144          * it does not validate, but the integrator may not have the
1145          * public key of the signer of the tag he is merging, while a
1146          * later auditor may have it while auditing, so let's not run
1147          * verify-signed-buffer here for now...
1148          *
1149          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1150          *      warn("warning: signed tag unverified.");
1151          */
1152         mergetag = xcalloc(1, sizeof(*mergetag));
1153         mergetag->key = xstrdup("mergetag");
1154         mergetag->value = buf;
1155         mergetag->len = size;
1156
1157         **tail = mergetag;
1158         *tail = &mergetag->next;
1159         return;
1160
1161 free_return:
1162         free(buf);
1163 }
1164
1165 static struct {
1166         char result;
1167         const char *check;
1168 } sigcheck_gpg_status[] = {
1169         { 'G', "\n[GNUPG:] GOODSIG " },
1170         { 'B', "\n[GNUPG:] BADSIG " },
1171         { 'U', "\n[GNUPG:] TRUST_NEVER" },
1172         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1173 };
1174
1175 static void parse_gpg_output(struct signature_check *sigc)
1176 {
1177         const char *buf = sigc->gpg_status;
1178         int i;
1179
1180         /* Iterate over all search strings */
1181         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1182                 const char *found, *next;
1183
1184                 found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
1185                 if (!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 char *msg, size_t msg_len,
1346                 const unsigned char *tree,
1347                 struct commit_list *parents, unsigned char *ret,
1348                 const char *author, const char *sign_commit)
1349 {
1350         struct commit_extra_header *extra = NULL, **tail = &extra;
1351         int result;
1352
1353         append_merge_tag_headers(parents, &tail);
1354         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1355                                       author, sign_commit, extra);
1356         free_commit_extra_headers(extra);
1357         return result;
1358 }
1359
1360 static int find_invalid_utf8(const char *buf, int len)
1361 {
1362         int offset = 0;
1363         static const unsigned int max_codepoint[] = {
1364                 0x7f, 0x7ff, 0xffff, 0x10ffff
1365         };
1366
1367         while (len) {
1368                 unsigned char c = *buf++;
1369                 int bytes, bad_offset;
1370                 unsigned int codepoint;
1371                 unsigned int min_val, max_val;
1372
1373                 len--;
1374                 offset++;
1375
1376                 /* Simple US-ASCII? No worries. */
1377                 if (c < 0x80)
1378                         continue;
1379
1380                 bad_offset = offset-1;
1381
1382                 /*
1383                  * Count how many more high bits set: that's how
1384                  * many more bytes this sequence should have.
1385                  */
1386                 bytes = 0;
1387                 while (c & 0x40) {
1388                         c <<= 1;
1389                         bytes++;
1390                 }
1391
1392                 /*
1393                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1394                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1395                  */
1396                 if (bytes < 1 || 3 < bytes)
1397                         return bad_offset;
1398
1399                 /* Do we *have* that many bytes? */
1400                 if (len < bytes)
1401                         return bad_offset;
1402
1403                 /*
1404                  * Place the encoded bits at the bottom of the value and compute the
1405                  * valid range.
1406                  */
1407                 codepoint = (c & 0x7f) >> bytes;
1408                 min_val = max_codepoint[bytes-1] + 1;
1409                 max_val = max_codepoint[bytes];
1410
1411                 offset += bytes;
1412                 len -= bytes;
1413
1414                 /* And verify that they are good continuation bytes */
1415                 do {
1416                         codepoint <<= 6;
1417                         codepoint |= *buf & 0x3f;
1418                         if ((*buf++ & 0xc0) != 0x80)
1419                                 return bad_offset;
1420                 } while (--bytes);
1421
1422                 /* Reject codepoints that are out of range for the sequence length. */
1423                 if (codepoint < min_val || codepoint > max_val)
1424                         return bad_offset;
1425                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1426                 if ((codepoint & 0x1ff800) == 0xd800)
1427                         return bad_offset;
1428                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1429                 if ((codepoint & 0xfffe) == 0xfffe)
1430                         return bad_offset;
1431                 /* So are anything in the range U+FDD0..U+FDEF. */
1432                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1433                         return bad_offset;
1434         }
1435         return -1;
1436 }
1437
1438 /*
1439  * This verifies that the buffer is in proper utf8 format.
1440  *
1441  * If it isn't, it assumes any non-utf8 characters are Latin1,
1442  * and does the conversion.
1443  */
1444 static int verify_utf8(struct strbuf *buf)
1445 {
1446         int ok = 1;
1447         long pos = 0;
1448
1449         for (;;) {
1450                 int bad;
1451                 unsigned char c;
1452                 unsigned char replace[2];
1453
1454                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1455                 if (bad < 0)
1456                         return ok;
1457                 pos += bad;
1458                 ok = 0;
1459                 c = buf->buf[pos];
1460                 strbuf_remove(buf, pos, 1);
1461
1462                 /* We know 'c' must be in the range 128-255 */
1463                 replace[0] = 0xc0 + (c >> 6);
1464                 replace[1] = 0x80 + (c & 0x3f);
1465                 strbuf_insert(buf, pos, replace, 2);
1466                 pos += 2;
1467         }
1468 }
1469
1470 static const char commit_utf8_warn[] =
1471 "Warning: commit message did not conform to UTF-8.\n"
1472 "You may want to amend it after fixing the message, or set the config\n"
1473 "variable i18n.commitencoding to the encoding your project uses.\n";
1474
1475 int commit_tree_extended(const char *msg, size_t msg_len,
1476                          const unsigned char *tree,
1477                          struct commit_list *parents, unsigned char *ret,
1478                          const char *author, const char *sign_commit,
1479                          struct commit_extra_header *extra)
1480 {
1481         int result;
1482         int encoding_is_utf8;
1483         struct strbuf buffer;
1484
1485         assert_sha1_type(tree, OBJ_TREE);
1486
1487         if (memchr(msg, '\0', msg_len))
1488                 return error("a NUL byte in commit log message not allowed.");
1489
1490         /* Not having i18n.commitencoding is the same as having utf-8 */
1491         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1492
1493         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1494         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1495
1496         /*
1497          * NOTE! This ordering means that the same exact tree merged with a
1498          * different order of parents will be a _different_ changeset even
1499          * if everything else stays the same.
1500          */
1501         while (parents) {
1502                 struct commit_list *next = parents->next;
1503                 struct commit *parent = parents->item;
1504
1505                 strbuf_addf(&buffer, "parent %s\n",
1506                             sha1_to_hex(parent->object.sha1));
1507                 free(parents);
1508                 parents = next;
1509         }
1510
1511         /* Person/date information */
1512         if (!author)
1513                 author = git_author_info(IDENT_STRICT);
1514         strbuf_addf(&buffer, "author %s\n", author);
1515         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1516         if (!encoding_is_utf8)
1517                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1518
1519         while (extra) {
1520                 add_extra_header(&buffer, extra);
1521                 extra = extra->next;
1522         }
1523         strbuf_addch(&buffer, '\n');
1524
1525         /* And add the comment */
1526         strbuf_add(&buffer, msg, msg_len);
1527
1528         /* And check the encoding */
1529         if (encoding_is_utf8 && !verify_utf8(&buffer))
1530                 fprintf(stderr, commit_utf8_warn);
1531
1532         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1533                 return -1;
1534
1535         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1536         strbuf_release(&buffer);
1537         return result;
1538 }
1539
1540 struct commit *get_merge_parent(const char *name)
1541 {
1542         struct object *obj;
1543         struct commit *commit;
1544         unsigned char sha1[20];
1545         if (get_sha1(name, sha1))
1546                 return NULL;
1547         obj = parse_object(sha1);
1548         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1549         if (commit && !commit->util) {
1550                 struct merge_remote_desc *desc;
1551                 desc = xmalloc(sizeof(*desc));
1552                 desc->obj = obj;
1553                 desc->name = strdup(name);
1554                 commit->util = desc;
1555         }
1556         return commit;
1557 }
1558
1559 /*
1560  * Append a commit to the end of the commit_list.
1561  *
1562  * next starts by pointing to the variable that holds the head of an
1563  * empty commit_list, and is updated to point to the "next" field of
1564  * the last item on the list as new commits are appended.
1565  *
1566  * Usage example:
1567  *
1568  *     struct commit_list *list;
1569  *     struct commit_list **next = &list;
1570  *
1571  *     next = commit_list_append(c1, next);
1572  *     next = commit_list_append(c2, next);
1573  *     assert(commit_list_count(list) == 2);
1574  *     return list;
1575  */
1576 struct commit_list **commit_list_append(struct commit *commit,
1577                                         struct commit_list **next)
1578 {
1579         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1580         new->item = commit;
1581         *next = new;
1582         new->next = NULL;
1583         return &new->next;
1584 }
1585
1586 void print_commit_list(struct commit_list *list,
1587                        const char *format_cur,
1588                        const char *format_last)
1589 {
1590         for ( ; list; list = list->next) {
1591                 const char *format = list->next ? format_cur : format_last;
1592                 printf(format, sha1_to_hex(list->item->object.sha1));
1593         }
1594 }