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 void set_commit_buffer(struct commit *commit, void *buffer)
 249 {
 250         commit->buffer = buffer;
 251 }
 252
 253 void free_commit_buffer(struct commit *commit)
 254 {
 255         free(commit->buffer);
 256         commit->buffer = NULL;
 257 }
 258
 259 const void *detach_commit_buffer(struct commit *commit)
 260 {
 261         void *ret = commit->buffer;
 262         commit->buffer = NULL;
 263         return ret;
 264 }
 265
 266 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 267 {
 268         const char *tail = buffer;
 269         const char *bufptr = buffer;
 270         unsigned char parent[20];
 271         struct commit_list **pptr;
 272         struct commit_graft *graft;
 273
 274         if (item->object.parsed)
 275                 return 0;
 276         item->object.parsed = 1;
 277         tail += size;
 278         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 279                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 280         if (get_sha1_hex(bufptr + 5, parent) < 0)
 281                 return error("bad tree pointer in commit %s",
 282                              sha1_to_hex(item->object.sha1));
 283         item->tree = lookup_tree(parent);
 284         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 285         pptr = &item->parents;
 286
 287         graft = lookup_commit_graft(item->object.sha1);
 288         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 289                 struct commit *new_parent;
 290
 291                 if (tail <= bufptr + 48 ||
 292                     get_sha1_hex(bufptr + 7, parent) ||
 293                     bufptr[47] != '\n')
 294                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 295                 bufptr += 48;
 296                 /*
 297                  * The clone is shallow if nr_parent < 0, and we must
 298                  * not traverse its real parents even when we unhide them.
 299                  */
 300                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 301                         continue;
 302                 new_parent = lookup_commit(parent);
 303                 if (new_parent)
 304                         pptr = &commit_list_insert(new_parent, pptr)->next;
 305         }
 306         if (graft) {
 307                 int i;
 308                 struct commit *new_parent;
 309                 for (i = 0; i < graft->nr_parent; i++) {
 310                         new_parent = lookup_commit(graft->parent[i]);
 311                         if (!new_parent)
 312                                 continue;
 313                         pptr = &commit_list_insert(new_parent, pptr)->next;
 314                 }
 315         }
 316         item->date = parse_commit_date(bufptr, tail);
 317
 318         return 0;
 319 }
 320
 321 int parse_commit(struct commit *item)
 322 {
 323         enum object_type type;
 324         void *buffer;
 325         unsigned long size;
 326         int ret;
 327
 328         if (!item)
 329                 return -1;
 330         if (item->object.parsed)
 331                 return 0;
 332         buffer = read_sha1_file(item->object.sha1, &type, &size);
 333         if (!buffer)
 334                 return error("Could not read %s",
 335                              sha1_to_hex(item->object.sha1));
 336         if (type != OBJ_COMMIT) {
 337                 free(buffer);
 338                 return error("Object %s not a commit",
 339                              sha1_to_hex(item->object.sha1));
 340         }
 341         ret = parse_commit_buffer(item, buffer, size);
 342         if (save_commit_buffer && !ret) {
 343                 set_commit_buffer(item, buffer);
 344                 return 0;
 345         }
 346         free(buffer);
 347         return ret;
 348 }
 349
 350 void parse_commit_or_die(struct commit *item)
 351 {
 352         if (parse_commit(item))
 353                 die("unable to parse commit %s",
 354                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 355 }
 356
 357 int find_commit_subject(const char *commit_buffer, const char **subject)
 358 {
 359         const char *eol;
 360         const char *p = commit_buffer;
 361
 362         while (*p && (*p != '\n' || p[1] != '\n'))
 363                 p++;
 364         if (*p) {
 365                 p += 2;
 366                 for (eol = p; *eol && *eol != '\n'; eol++)
 367                         ; /* do nothing */
 368         } else
 369                 eol = p;
 370
 371         *subject = p;
 372
 373         return eol - p;
 374 }
 375
 376 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 377 {
 378         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 379         new_list->item = item;
 380         new_list->next = *list_p;
 381         *list_p = new_list;
 382         return new_list;
 383 }
 384
 385 unsigned commit_list_count(const struct commit_list *l)
 386 {
 387         unsigned c = 0;
 388         for (; l; l = l->next )
 389                 c++;
 390         return c;
 391 }
 392
 393 struct commit_list *copy_commit_list(struct commit_list *list)
 394 {
 395         struct commit_list *head = NULL;
 396         struct commit_list **pp = &head;
 397         while (list) {
 398                 struct commit_list *new;
 399                 new = xmalloc(sizeof(struct commit_list));
 400                 new->item = list->item;
 401                 new->next = NULL;
 402                 *pp = new;
 403                 pp = &new->next;
 404                 list = list->next;
 405         }
 406         return head;
 407 }
 408
 409 void free_commit_list(struct commit_list *list)
 410 {
 411         while (list) {
 412                 struct commit_list *temp = list;
 413                 list = temp->next;
 414                 free(temp);
 415         }
 416 }
 417
 418 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 419 {
 420         struct commit_list **pp = list;
 421         struct commit_list *p;
 422         while ((p = *pp) != NULL) {
 423                 if (p->item->date < item->date) {
 424                         break;
 425                 }
 426                 pp = &p->next;
 427         }
 428         return commit_list_insert(item, pp);
 429 }
 430
 431 static int commit_list_compare_by_date(const void *a, const void *b)
 432 {
 433         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 434         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 435         if (a_date < b_date)
 436                 return 1;
 437         if (a_date > b_date)
 438                 return -1;
 439         return 0;
 440 }
 441
 442 static void *commit_list_get_next(const void *a)
 443 {
 444         return ((const struct commit_list *)a)->next;
 445 }
 446
 447 static void commit_list_set_next(void *a, void *next)
 448 {
 449         ((struct commit_list *)a)->next = next;
 450 }
 451
 452 void commit_list_sort_by_date(struct commit_list **list)
 453 {
 454         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 455                                 commit_list_compare_by_date);
 456 }
 457
 458 struct commit *pop_most_recent_commit(struct commit_list **list,
 459                                       unsigned int mark)
 460 {
 461         struct commit *ret = (*list)->item;
 462         struct commit_list *parents = ret->parents;
 463         struct commit_list *old = *list;
 464
 465         *list = (*list)->next;
 466         free(old);
 467
 468         while (parents) {
 469                 struct commit *commit = parents->item;
 470                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 471                         commit->object.flags |= mark;
 472                         commit_list_insert_by_date(commit, list);
 473                 }
 474                 parents = parents->next;
 475         }
 476         return ret;
 477 }
 478
 479 static void clear_commit_marks_1(struct commit_list **plist,
 480                                  struct commit *commit, unsigned int mark)
 481 {
 482         while (commit) {
 483                 struct commit_list *parents;
 484
 485                 if (!(mark & commit->object.flags))
 486                         return;
 487
 488                 commit->object.flags &= ~mark;
 489
 490                 parents = commit->parents;
 491                 if (!parents)
 492                         return;
 493
 494                 while ((parents = parents->next))
 495                         commit_list_insert(parents->item, plist);
 496
 497                 commit = commit->parents->item;
 498         }
 499 }
 500
 501 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 502 {
 503         struct commit_list *list = NULL;
 504
 505         while (nr--) {
 506                 commit_list_insert(*commit, &list);
 507                 commit++;
 508         }
 509         while (list)
 510                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 511 }
 512
 513 void clear_commit_marks(struct commit *commit, unsigned int mark)
 514 {
 515         clear_commit_marks_many(1, &commit, mark);
 516 }
 517
 518 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 519 {
 520         struct object *object;
 521         struct commit *commit;
 522         unsigned int i;
 523
 524         for (i = 0; i < a->nr; i++) {
 525                 object = a->objects[i].item;
 526                 commit = lookup_commit_reference_gently(object->sha1, 1);
 527                 if (commit)
 528                         clear_commit_marks(commit, mark);
 529         }
 530 }
 531
 532 struct commit *pop_commit(struct commit_list **stack)
 533 {
 534         struct commit_list *top = *stack;
 535         struct commit *item = top ? top->item : NULL;
 536
 537         if (top) {
 538                 *stack = top->next;
 539                 free(top);
 540         }
 541         return item;
 542 }
 543
 544 /*
 545  * Topological sort support
 546  */
 547
 548 /* count number of children that have not been emitted */
 549 define_commit_slab(indegree_slab, int);
 550
 551 /* record author-date for each commit object */
 552 define_commit_slab(author_date_slab, unsigned long);
 553
 554 static void record_author_date(struct author_date_slab *author_date,
 555                                struct commit *commit)
 556 {
 557         const char *buf, *line_end, *ident_line;
 558         char *buffer = NULL;
 559         struct ident_split ident;
 560         char *date_end;
 561         unsigned long date;
 562
 563         if (!commit->buffer) {
 564                 unsigned long size;
 565                 enum object_type type;
 566                 buffer = read_sha1_file(commit->object.sha1, &type, &size);
 567                 if (!buffer)
 568                         return;
 569         }
 570
 571         for (buf = commit->buffer ? commit->buffer : buffer;
 572              buf;
 573              buf = line_end + 1) {
 574                 line_end = strchrnul(buf, '\n');
 575                 ident_line = skip_prefix(buf, "author ");
 576                 if (!ident_line) {
 577                         if (!line_end[0] || line_end[1] == '\n')
 578                                 return; /* end of header */
 579                         continue;
 580                 }
 581                 if (split_ident_line(&ident,
 582                                      ident_line, line_end - ident_line) ||
 583                     !ident.date_begin || !ident.date_end)
 584                         goto fail_exit; /* malformed "author" line */
 585                 break;
 586         }
 587
 588         date = strtoul(ident.date_begin, &date_end, 10);
 589         if (date_end != ident.date_end)
 590                 goto fail_exit; /* malformed date */
 591         *(author_date_slab_at(author_date, commit)) = date;
 592
 593 fail_exit:
 594         free(buffer);
 595 }
 596
 597 static int compare_commits_by_author_date(const void *a_, const void *b_,
 598                                           void *cb_data)
 599 {
 600         const struct commit *a = a_, *b = b_;
 601         struct author_date_slab *author_date = cb_data;
 602         unsigned long a_date = *(author_date_slab_at(author_date, a));
 603         unsigned long b_date = *(author_date_slab_at(author_date, b));
 604
 605         /* newer commits with larger date first */
 606         if (a_date < b_date)
 607                 return 1;
 608         else if (a_date > b_date)
 609                 return -1;
 610         return 0;
 611 }
 612
 613 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 614 {
 615         const struct commit *a = a_, *b = b_;
 616         /* newer commits with larger date first */
 617         if (a->date < b->date)
 618                 return 1;
 619         else if (a->date > b->date)
 620                 return -1;
 621         return 0;
 622 }
 623
 624 /*
 625  * Performs an in-place topological sort on the list supplied.
 626  */
 627 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 628 {
 629         struct commit_list *next, *orig = *list;
 630         struct commit_list **pptr;
 631         struct indegree_slab indegree;
 632         struct prio_queue queue;
 633         struct commit *commit;
 634         struct author_date_slab author_date;
 635
 636         if (!orig)
 637                 return;
 638         *list = NULL;
 639
 640         init_indegree_slab(&indegree);
 641         memset(&queue, '\0', sizeof(queue));
 642
 643         switch (sort_order) {
 644         default: /* REV_SORT_IN_GRAPH_ORDER */
 645                 queue.compare = NULL;
 646                 break;
 647         case REV_SORT_BY_COMMIT_DATE:
 648                 queue.compare = compare_commits_by_commit_date;
 649                 break;
 650         case REV_SORT_BY_AUTHOR_DATE:
 651                 init_author_date_slab(&author_date);
 652                 queue.compare = compare_commits_by_author_date;
 653                 queue.cb_data = &author_date;
 654                 break;
 655         }
 656
 657         /* Mark them and clear the indegree */
 658         for (next = orig; next; next = next->next) {
 659                 struct commit *commit = next->item;
 660                 *(indegree_slab_at(&indegree, commit)) = 1;
 661                 /* also record the author dates, if needed */
 662                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 663                         record_author_date(&author_date, commit);
 664         }
 665
 666         /* update the indegree */
 667         for (next = orig; next; next = next->next) {
 668                 struct commit_list *parents = next->item->parents;
 669                 while (parents) {
 670                         struct commit *parent = parents->item;
 671                         int *pi = indegree_slab_at(&indegree, parent);
 672
 673                         if (*pi)
 674                                 (*pi)++;
 675                         parents = parents->next;
 676                 }
 677         }
 678
 679         /*
 680          * find the tips
 681          *
 682          * tips are nodes not reachable from any other node in the list
 683          *
 684          * the tips serve as a starting set for the work queue.
 685          */
 686         for (next = orig; next; next = next->next) {
 687                 struct commit *commit = next->item;
 688
 689                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 690                         prio_queue_put(&queue, commit);
 691         }
 692
 693         /*
 694          * This is unfortunate; the initial tips need to be shown
 695          * in the order given from the revision traversal machinery.
 696          */
 697         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 698                 prio_queue_reverse(&queue);
 699
 700         /* We no longer need the commit list */
 701         free_commit_list(orig);
 702
 703         pptr = list;
 704         *list = NULL;
 705         while ((commit = prio_queue_get(&queue)) != NULL) {
 706                 struct commit_list *parents;
 707
 708                 for (parents = commit->parents; parents ; parents = parents->next) {
 709                         struct commit *parent = parents->item;
 710                         int *pi = indegree_slab_at(&indegree, parent);
 711
 712                         if (!*pi)
 713                                 continue;
 714
 715                         /*
 716                          * parents are only enqueued for emission
 717                          * when all their children have been emitted thereby
 718                          * guaranteeing topological order.
 719                          */
 720                         if (--(*pi) == 1)
 721                                 prio_queue_put(&queue, parent);
 722                 }
 723                 /*
 724                  * all children of commit have already been
 725                  * emitted. we can emit it now.
 726                  */
 727                 *(indegree_slab_at(&indegree, commit)) = 0;
 728
 729                 pptr = &commit_list_insert(commit, pptr)->next;
 730         }
 731
 732         clear_indegree_slab(&indegree);
 733         clear_prio_queue(&queue);
 734         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 735                 clear_author_date_slab(&author_date);
 736 }
 737
 738 /* merge-base stuff */
 739
 740 /* Remember to update object flag allocation in object.h */
 741 #define PARENT1         (1u<<16)
 742 #define PARENT2         (1u<<17)
 743 #define STALE           (1u<<18)
 744 #define RESULT          (1u<<19)
 745
 746 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 747
 748 static struct commit *interesting(struct commit_list *list)
 749 {
 750         while (list) {
 751                 struct commit *commit = list->item;
 752                 list = list->next;
 753                 if (commit->object.flags & STALE)
 754                         continue;
 755                 return commit;
 756         }
 757         return NULL;
 758 }
 759
 760 /* all input commits in one and twos[] must have been parsed! */
 761 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 762 {
 763         struct commit_list *list = NULL;
 764         struct commit_list *result = NULL;
 765         int i;
 766
 767         one->object.flags |= PARENT1;
 768         commit_list_insert_by_date(one, &list);
 769         if (!n)
 770                 return list;
 771         for (i = 0; i < n; i++) {
 772                 twos[i]->object.flags |= PARENT2;
 773                 commit_list_insert_by_date(twos[i], &list);
 774         }
 775
 776         while (interesting(list)) {
 777                 struct commit *commit;
 778                 struct commit_list *parents;
 779                 struct commit_list *next;
 780                 int flags;
 781
 782                 commit = list->item;
 783                 next = list->next;
 784                 free(list);
 785                 list = next;
 786
 787                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 788                 if (flags == (PARENT1 | PARENT2)) {
 789                         if (!(commit->object.flags & RESULT)) {
 790                                 commit->object.flags |= RESULT;
 791                                 commit_list_insert_by_date(commit, &result);
 792                         }
 793                         /* Mark parents of a found merge stale */
 794                         flags |= STALE;
 795                 }
 796                 parents = commit->parents;
 797                 while (parents) {
 798                         struct commit *p = parents->item;
 799                         parents = parents->next;
 800                         if ((p->object.flags & flags) == flags)
 801                                 continue;
 802                         if (parse_commit(p))
 803                                 return NULL;
 804                         p->object.flags |= flags;
 805                         commit_list_insert_by_date(p, &list);
 806                 }
 807         }
 808
 809         free_commit_list(list);
 810         return result;
 811 }
 812
 813 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 814 {
 815         struct commit_list *list = NULL;
 816         struct commit_list *result = NULL;
 817         int i;
 818
 819         for (i = 0; i < n; i++) {
 820                 if (one == twos[i])
 821                         /*
 822                          * We do not mark this even with RESULT so we do not
 823                          * have to clean it up.
 824                          */
 825                         return commit_list_insert(one, &result);
 826         }
 827
 828         if (parse_commit(one))
 829                 return NULL;
 830         for (i = 0; i < n; i++) {
 831                 if (parse_commit(twos[i]))
 832                         return NULL;
 833         }
 834
 835         list = paint_down_to_common(one, n, twos);
 836
 837         while (list) {
 838                 struct commit_list *next = list->next;
 839                 if (!(list->item->object.flags & STALE))
 840                         commit_list_insert_by_date(list->item, &result);
 841                 free(list);
 842                 list = next;
 843         }
 844         return result;
 845 }
 846
 847 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 848 {
 849         struct commit_list *i, *j, *k, *ret = NULL;
 850
 851         if (!in)
 852                 return ret;
 853
 854         commit_list_insert(in->item, &ret);
 855
 856         for (i = in->next; i; i = i->next) {
 857                 struct commit_list *new = NULL, *end = NULL;
 858
 859                 for (j = ret; j; j = j->next) {
 860                         struct commit_list *bases;
 861                         bases = get_merge_bases(i->item, j->item, 1);
 862                         if (!new)
 863                                 new = bases;
 864                         else
 865                                 end->next = bases;
 866                         for (k = bases; k; k = k->next)
 867                                 end = k;
 868                 }
 869                 ret = new;
 870         }
 871         return ret;
 872 }
 873
 874 static int remove_redundant(struct commit **array, int cnt)
 875 {
 876         /*
 877          * Some commit in the array may be an ancestor of
 878          * another commit.  Move such commit to the end of
 879          * the array, and return the number of commits that
 880          * are independent from each other.
 881          */
 882         struct commit **work;
 883         unsigned char *redundant;
 884         int *filled_index;
 885         int i, j, filled;
 886
 887         work = xcalloc(cnt, sizeof(*work));
 888         redundant = xcalloc(cnt, 1);
 889         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 890
 891         for (i = 0; i < cnt; i++)
 892                 parse_commit(array[i]);
 893         for (i = 0; i < cnt; i++) {
 894                 struct commit_list *common;
 895
 896                 if (redundant[i])
 897                         continue;
 898                 for (j = filled = 0; j < cnt; j++) {
 899                         if (i == j || redundant[j])
 900                                 continue;
 901                         filled_index[filled] = j;
 902                         work[filled++] = array[j];
 903                 }
 904                 common = paint_down_to_common(array[i], filled, work);
 905                 if (array[i]->object.flags & PARENT2)
 906                         redundant[i] = 1;
 907                 for (j = 0; j < filled; j++)
 908                         if (work[j]->object.flags & PARENT1)
 909                                 redundant[filled_index[j]] = 1;
 910                 clear_commit_marks(array[i], all_flags);
 911                 for (j = 0; j < filled; j++)
 912                         clear_commit_marks(work[j], all_flags);
 913                 free_commit_list(common);
 914         }
 915
 916         /* Now collect the result */
 917         memcpy(work, array, sizeof(*array) * cnt);
 918         for (i = filled = 0; i < cnt; i++)
 919                 if (!redundant[i])
 920                         array[filled++] = work[i];
 921         for (j = filled, i = 0; i < cnt; i++)
 922                 if (redundant[i])
 923                         array[j++] = work[i];
 924         free(work);
 925         free(redundant);
 926         free(filled_index);
 927         return filled;
 928 }
 929
 930 struct commit_list *get_merge_bases_many(struct commit *one,
 931                                          int n,
 932                                          struct commit **twos,
 933                                          int cleanup)
 934 {
 935         struct commit_list *list;
 936         struct commit **rslt;
 937         struct commit_list *result;
 938         int cnt, i;
 939
 940         result = merge_bases_many(one, n, twos);
 941         for (i = 0; i < n; i++) {
 942                 if (one == twos[i])
 943                         return result;
 944         }
 945         if (!result || !result->next) {
 946                 if (cleanup) {
 947                         clear_commit_marks(one, all_flags);
 948                         clear_commit_marks_many(n, twos, all_flags);
 949                 }
 950                 return result;
 951         }
 952
 953         /* There are more than one */
 954         cnt = 0;
 955         list = result;
 956         while (list) {
 957                 list = list->next;
 958                 cnt++;
 959         }
 960         rslt = xcalloc(cnt, sizeof(*rslt));
 961         for (list = result, i = 0; list; list = list->next)
 962                 rslt[i++] = list->item;
 963         free_commit_list(result);
 964
 965         clear_commit_marks(one, all_flags);
 966         clear_commit_marks_many(n, twos, all_flags);
 967
 968         cnt = remove_redundant(rslt, cnt);
 969         result = NULL;
 970         for (i = 0; i < cnt; i++)
 971                 commit_list_insert_by_date(rslt[i], &result);
 972         free(rslt);
 973         return result;
 974 }
 975
 976 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 977                                     int cleanup)
 978 {
 979         return get_merge_bases_many(one, 1, &two, cleanup);
 980 }
 981
 982 /*
 983  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 984  */
 985 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 986 {
 987         if (!with_commit)
 988                 return 1;
 989         while (with_commit) {
 990                 struct commit *other;
 991
 992                 other = with_commit->item;
 993                 with_commit = with_commit->next;
 994                 if (in_merge_bases(other, commit))
 995                         return 1;
 996         }
 997         return 0;
 998 }
 999
1000 /*
1001  * Is "commit" an ancestor of one of the "references"?
1002  */
1003 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1004 {
1005         struct commit_list *bases;
1006         int ret = 0, i;
1007
1008         if (parse_commit(commit))
1009                 return ret;
1010         for (i = 0; i < nr_reference; i++)
1011                 if (parse_commit(reference[i]))
1012                         return ret;
1013
1014         bases = paint_down_to_common(commit, nr_reference, reference);
1015         if (commit->object.flags & PARENT2)
1016                 ret = 1;
1017         clear_commit_marks(commit, all_flags);
1018         clear_commit_marks_many(nr_reference, reference, all_flags);
1019         free_commit_list(bases);
1020         return ret;
1021 }
1022
1023 /*
1024  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1025  */
1026 int in_merge_bases(struct commit *commit, struct commit *reference)
1027 {
1028         return in_merge_bases_many(commit, 1, &reference);
1029 }
1030
1031 struct commit_list *reduce_heads(struct commit_list *heads)
1032 {
1033         struct commit_list *p;
1034         struct commit_list *result = NULL, **tail = &result;
1035         struct commit **array;
1036         int num_head, i;
1037
1038         if (!heads)
1039                 return NULL;
1040
1041         /* Uniquify */
1042         for (p = heads; p; p = p->next)
1043                 p->item->object.flags &= ~STALE;
1044         for (p = heads, num_head = 0; p; p = p->next) {
1045                 if (p->item->object.flags & STALE)
1046                         continue;
1047                 p->item->object.flags |= STALE;
1048                 num_head++;
1049         }
1050         array = xcalloc(sizeof(*array), num_head);
1051         for (p = heads, i = 0; p; p = p->next) {
1052                 if (p->item->object.flags & STALE) {
1053                         array[i++] = p->item;
1054                         p->item->object.flags &= ~STALE;
1055                 }
1056         }
1057         num_head = remove_redundant(array, num_head);
1058         for (i = 0; i < num_head; i++)
1059                 tail = &commit_list_insert(array[i], tail)->next;
1060         return result;
1061 }
1062
1063 static const char gpg_sig_header[] = "gpgsig";
1064 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1065
1066 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1067 {
1068         struct strbuf sig = STRBUF_INIT;
1069         int inspos, copypos;
1070
1071         /* find the end of the header */
1072         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1073
1074         if (!keyid || !*keyid)
1075                 keyid = get_signing_key();
1076         if (sign_buffer(buf, &sig, keyid)) {
1077                 strbuf_release(&sig);
1078                 return -1;
1079         }
1080
1081         for (copypos = 0; sig.buf[copypos]; ) {
1082                 const char *bol = sig.buf + copypos;
1083                 const char *eol = strchrnul(bol, '\n');
1084                 int len = (eol - bol) + !!*eol;
1085
1086                 if (!copypos) {
1087                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1088                         inspos += gpg_sig_header_len;
1089                 }
1090                 strbuf_insert(buf, inspos++, " ", 1);
1091                 strbuf_insert(buf, inspos, bol, len);
1092                 inspos += len;
1093                 copypos += len;
1094         }
1095         strbuf_release(&sig);
1096         return 0;
1097 }
1098
1099 int parse_signed_commit(const unsigned char *sha1,
1100                         struct strbuf *payload, struct strbuf *signature)
1101 {
1102         unsigned long size;
1103         enum object_type type;
1104         char *buffer = read_sha1_file(sha1, &type, &size);
1105         int in_signature, saw_signature = -1;
1106         char *line, *tail;
1107
1108         if (!buffer || type != OBJ_COMMIT)
1109                 goto cleanup;
1110
1111         line = buffer;
1112         tail = buffer + size;
1113         in_signature = 0;
1114         saw_signature = 0;
1115         while (line < tail) {
1116                 const char *sig = NULL;
1117                 char *next = memchr(line, '\n', tail - line);
1118
1119                 next = next ? next + 1 : tail;
1120                 if (in_signature && line[0] == ' ')
1121                         sig = line + 1;
1122                 else if (starts_with(line, gpg_sig_header) &&
1123                          line[gpg_sig_header_len] == ' ')
1124                         sig = line + gpg_sig_header_len + 1;
1125                 if (sig) {
1126                         strbuf_add(signature, sig, next - sig);
1127                         saw_signature = 1;
1128                         in_signature = 1;
1129                 } else {
1130                         if (*line == '\n')
1131                                 /* dump the whole remainder of the buffer */
1132                                 next = tail;
1133                         strbuf_add(payload, line, next - line);
1134                         in_signature = 0;
1135                 }
1136                 line = next;
1137         }
1138  cleanup:
1139         free(buffer);
1140         return saw_signature;
1141 }
1142
1143 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1144 {
1145         struct merge_remote_desc *desc;
1146         struct commit_extra_header *mergetag;
1147         char *buf;
1148         unsigned long size, len;
1149         enum object_type type;
1150
1151         desc = merge_remote_util(parent);
1152         if (!desc || !desc->obj)
1153                 return;
1154         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1155         if (!buf || type != OBJ_TAG)
1156                 goto free_return;
1157         len = parse_signature(buf, size);
1158         if (size == len)
1159                 goto free_return;
1160         /*
1161          * We could verify this signature and either omit the tag when
1162          * it does not validate, but the integrator may not have the
1163          * public key of the signer of the tag he is merging, while a
1164          * later auditor may have it while auditing, so let's not run
1165          * verify-signed-buffer here for now...
1166          *
1167          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1168          *      warn("warning: signed tag unverified.");
1169          */
1170         mergetag = xcalloc(1, sizeof(*mergetag));
1171         mergetag->key = xstrdup("mergetag");
1172         mergetag->value = buf;
1173         mergetag->len = size;
1174
1175         **tail = mergetag;
1176         *tail = &mergetag->next;
1177         return;
1178
1179 free_return:
1180         free(buf);
1181 }
1182
1183 static struct {
1184         char result;
1185         const char *check;
1186 } sigcheck_gpg_status[] = {
1187         { 'G', "\n[GNUPG:] GOODSIG " },
1188         { 'B', "\n[GNUPG:] BADSIG " },
1189         { 'U', "\n[GNUPG:] TRUST_NEVER" },
1190         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1191 };
1192
1193 static void parse_gpg_output(struct signature_check *sigc)
1194 {
1195         const char *buf = sigc->gpg_status;
1196         int i;
1197
1198         /* Iterate over all search strings */
1199         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1200                 const char *found, *next;
1201
1202                 found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
1203                 if (!found) {
1204                         found = strstr(buf, sigcheck_gpg_status[i].check);
1205                         if (!found)
1206                                 continue;
1207                         found += strlen(sigcheck_gpg_status[i].check);
1208                 }
1209                 sigc->result = sigcheck_gpg_status[i].result;
1210                 /* The trust messages are not followed by key/signer information */
1211                 if (sigc->result != 'U') {
1212                         sigc->key = xmemdupz(found, 16);
1213                         found += 17;
1214                         next = strchrnul(found, '\n');
1215                         sigc->signer = xmemdupz(found, next - found);
1216                 }
1217         }
1218 }
1219
1220 void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1221 {
1222         struct strbuf payload = STRBUF_INIT;
1223         struct strbuf signature = STRBUF_INIT;
1224         struct strbuf gpg_output = STRBUF_INIT;
1225         struct strbuf gpg_status = STRBUF_INIT;
1226         int status;
1227
1228         sigc->result = 'N';
1229
1230         if (parse_signed_commit(commit->object.sha1,
1231                                 &payload, &signature) <= 0)
1232                 goto out;
1233         status = verify_signed_buffer(payload.buf, payload.len,
1234                                       signature.buf, signature.len,
1235                                       &gpg_output, &gpg_status);
1236         if (status && !gpg_output.len)
1237                 goto out;
1238         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1239         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1240         parse_gpg_output(sigc);
1241
1242  out:
1243         strbuf_release(&gpg_status);
1244         strbuf_release(&gpg_output);
1245         strbuf_release(&payload);
1246         strbuf_release(&signature);
1247 }
1248
1249
1250
1251 void append_merge_tag_headers(struct commit_list *parents,
1252                               struct commit_extra_header ***tail)
1253 {
1254         while (parents) {
1255                 struct commit *parent = parents->item;
1256                 handle_signed_tag(parent, tail);
1257                 parents = parents->next;
1258         }
1259 }
1260
1261 static void add_extra_header(struct strbuf *buffer,
1262                              struct commit_extra_header *extra)
1263 {
1264         strbuf_addstr(buffer, extra->key);
1265         if (extra->len)
1266                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1267         else
1268                 strbuf_addch(buffer, '\n');
1269 }
1270
1271 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1272                                                       const char **exclude)
1273 {
1274         struct commit_extra_header *extra = NULL;
1275         unsigned long size;
1276         enum object_type type;
1277         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1278         if (buffer && type == OBJ_COMMIT)
1279                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1280         free(buffer);
1281         return extra;
1282 }
1283
1284 static inline int standard_header_field(const char *field, size_t len)
1285 {
1286         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1287                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1288                 (len == 6 && !memcmp(field, "author ", 7)) ||
1289                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1290                 (len == 8 && !memcmp(field, "encoding ", 9)));
1291 }
1292
1293 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1294 {
1295         if (!exclude)
1296                 return 0;
1297
1298         while (*exclude) {
1299                 size_t xlen = strlen(*exclude);
1300                 if (len == xlen &&
1301                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1302                         return 1;
1303                 exclude++;
1304         }
1305         return 0;
1306 }
1307
1308 static struct commit_extra_header *read_commit_extra_header_lines(
1309         const char *buffer, size_t size,
1310         const char **exclude)
1311 {
1312         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1313         const char *line, *next, *eof, *eob;
1314         struct strbuf buf = STRBUF_INIT;
1315
1316         for (line = buffer, eob = line + size;
1317              line < eob && *line != '\n';
1318              line = next) {
1319                 next = memchr(line, '\n', eob - line);
1320                 next = next ? next + 1 : eob;
1321                 if (*line == ' ') {
1322                         /* continuation */
1323                         if (it)
1324                                 strbuf_add(&buf, line + 1, next - (line + 1));
1325                         continue;
1326                 }
1327                 if (it)
1328                         it->value = strbuf_detach(&buf, &it->len);
1329                 strbuf_reset(&buf);
1330                 it = NULL;
1331
1332                 eof = strchr(line, ' ');
1333                 if (next <= eof)
1334                         eof = next;
1335
1336                 if (standard_header_field(line, eof - line) ||
1337                     excluded_header_field(line, eof - line, exclude))
1338                         continue;
1339
1340                 it = xcalloc(1, sizeof(*it));
1341                 it->key = xmemdupz(line, eof-line);
1342                 *tail = it;
1343                 tail = &it->next;
1344                 if (eof + 1 < next)
1345                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1346         }
1347         if (it)
1348                 it->value = strbuf_detach(&buf, &it->len);
1349         return extra;
1350 }
1351
1352 void free_commit_extra_headers(struct commit_extra_header *extra)
1353 {
1354         while (extra) {
1355                 struct commit_extra_header *next = extra->next;
1356                 free(extra->key);
1357                 free(extra->value);
1358                 free(extra);
1359                 extra = next;
1360         }
1361 }
1362
1363 int commit_tree(const char *msg, size_t msg_len,
1364                 const unsigned char *tree,
1365                 struct commit_list *parents, unsigned char *ret,
1366                 const char *author, const char *sign_commit)
1367 {
1368         struct commit_extra_header *extra = NULL, **tail = &extra;
1369         int result;
1370
1371         append_merge_tag_headers(parents, &tail);
1372         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1373                                       author, sign_commit, extra);
1374         free_commit_extra_headers(extra);
1375         return result;
1376 }
1377
1378 static int find_invalid_utf8(const char *buf, int len)
1379 {
1380         int offset = 0;
1381         static const unsigned int max_codepoint[] = {
1382                 0x7f, 0x7ff, 0xffff, 0x10ffff
1383         };
1384
1385         while (len) {
1386                 unsigned char c = *buf++;
1387                 int bytes, bad_offset;
1388                 unsigned int codepoint;
1389                 unsigned int min_val, max_val;
1390
1391                 len--;
1392                 offset++;
1393
1394                 /* Simple US-ASCII? No worries. */
1395                 if (c < 0x80)
1396                         continue;
1397
1398                 bad_offset = offset-1;
1399
1400                 /*
1401                  * Count how many more high bits set: that's how
1402                  * many more bytes this sequence should have.
1403                  */
1404                 bytes = 0;
1405                 while (c & 0x40) {
1406                         c <<= 1;
1407                         bytes++;
1408                 }
1409
1410                 /*
1411                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1412                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1413                  */
1414                 if (bytes < 1 || 3 < bytes)
1415                         return bad_offset;
1416
1417                 /* Do we *have* that many bytes? */
1418                 if (len < bytes)
1419                         return bad_offset;
1420
1421                 /*
1422                  * Place the encoded bits at the bottom of the value and compute the
1423                  * valid range.
1424                  */
1425                 codepoint = (c & 0x7f) >> bytes;
1426                 min_val = max_codepoint[bytes-1] + 1;
1427                 max_val = max_codepoint[bytes];
1428
1429                 offset += bytes;
1430                 len -= bytes;
1431
1432                 /* And verify that they are good continuation bytes */
1433                 do {
1434                         codepoint <<= 6;
1435                         codepoint |= *buf & 0x3f;
1436                         if ((*buf++ & 0xc0) != 0x80)
1437                                 return bad_offset;
1438                 } while (--bytes);
1439
1440                 /* Reject codepoints that are out of range for the sequence length. */
1441                 if (codepoint < min_val || codepoint > max_val)
1442                         return bad_offset;
1443                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1444                 if ((codepoint & 0x1ff800) == 0xd800)
1445                         return bad_offset;
1446                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1447                 if ((codepoint & 0xfffe) == 0xfffe)
1448                         return bad_offset;
1449                 /* So are anything in the range U+FDD0..U+FDEF. */
1450                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1451                         return bad_offset;
1452         }
1453         return -1;
1454 }
1455
1456 /*
1457  * This verifies that the buffer is in proper utf8 format.
1458  *
1459  * If it isn't, it assumes any non-utf8 characters are Latin1,
1460  * and does the conversion.
1461  */
1462 static int verify_utf8(struct strbuf *buf)
1463 {
1464         int ok = 1;
1465         long pos = 0;
1466
1467         for (;;) {
1468                 int bad;
1469                 unsigned char c;
1470                 unsigned char replace[2];
1471
1472                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1473                 if (bad < 0)
1474                         return ok;
1475                 pos += bad;
1476                 ok = 0;
1477                 c = buf->buf[pos];
1478                 strbuf_remove(buf, pos, 1);
1479
1480                 /* We know 'c' must be in the range 128-255 */
1481                 replace[0] = 0xc0 + (c >> 6);
1482                 replace[1] = 0x80 + (c & 0x3f);
1483                 strbuf_insert(buf, pos, replace, 2);
1484                 pos += 2;
1485         }
1486 }
1487
1488 static const char commit_utf8_warn[] =
1489 "Warning: commit message did not conform to UTF-8.\n"
1490 "You may want to amend it after fixing the message, or set the config\n"
1491 "variable i18n.commitencoding to the encoding your project uses.\n";
1492
1493 int commit_tree_extended(const char *msg, size_t msg_len,
1494                          const unsigned char *tree,
1495                          struct commit_list *parents, unsigned char *ret,
1496                          const char *author, const char *sign_commit,
1497                          struct commit_extra_header *extra)
1498 {
1499         int result;
1500         int encoding_is_utf8;
1501         struct strbuf buffer;
1502
1503         assert_sha1_type(tree, OBJ_TREE);
1504
1505         if (memchr(msg, '\0', msg_len))
1506                 return error("a NUL byte in commit log message not allowed.");
1507
1508         /* Not having i18n.commitencoding is the same as having utf-8 */
1509         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1510
1511         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1512         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1513
1514         /*
1515          * NOTE! This ordering means that the same exact tree merged with a
1516          * different order of parents will be a _different_ changeset even
1517          * if everything else stays the same.
1518          */
1519         while (parents) {
1520                 struct commit_list *next = parents->next;
1521                 struct commit *parent = parents->item;
1522
1523                 strbuf_addf(&buffer, "parent %s\n",
1524                             sha1_to_hex(parent->object.sha1));
1525                 free(parents);
1526                 parents = next;
1527         }
1528
1529         /* Person/date information */
1530         if (!author)
1531                 author = git_author_info(IDENT_STRICT);
1532         strbuf_addf(&buffer, "author %s\n", author);
1533         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1534         if (!encoding_is_utf8)
1535                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1536
1537         while (extra) {
1538                 add_extra_header(&buffer, extra);
1539                 extra = extra->next;
1540         }
1541         strbuf_addch(&buffer, '\n');
1542
1543         /* And add the comment */
1544         strbuf_add(&buffer, msg, msg_len);
1545
1546         /* And check the encoding */
1547         if (encoding_is_utf8 && !verify_utf8(&buffer))
1548                 fprintf(stderr, commit_utf8_warn);
1549
1550         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1551                 return -1;
1552
1553         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1554         strbuf_release(&buffer);
1555         return result;
1556 }
1557
1558 struct commit *get_merge_parent(const char *name)
1559 {
1560         struct object *obj;
1561         struct commit *commit;
1562         unsigned char sha1[20];
1563         if (get_sha1(name, sha1))
1564                 return NULL;
1565         obj = parse_object(sha1);
1566         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1567         if (commit && !commit->util) {
1568                 struct merge_remote_desc *desc;
1569                 desc = xmalloc(sizeof(*desc));
1570                 desc->obj = obj;
1571                 desc->name = strdup(name);
1572                 commit->util = desc;
1573         }
1574         return commit;
1575 }
1576
1577 /*
1578  * Append a commit to the end of the commit_list.
1579  *
1580  * next starts by pointing to the variable that holds the head of an
1581  * empty commit_list, and is updated to point to the "next" field of
1582  * the last item on the list as new commits are appended.
1583  *
1584  * Usage example:
1585  *
1586  *     struct commit_list *list;
1587  *     struct commit_list **next = &list;
1588  *
1589  *     next = commit_list_append(c1, next);
1590  *     next = commit_list_append(c2, next);
1591  *     assert(commit_list_count(list) == 2);
1592  *     return list;
1593  */
1594 struct commit_list **commit_list_append(struct commit *commit,
1595                                         struct commit_list **next)
1596 {
1597         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1598         new->item = commit;
1599         *next = new;
1600         new->next = NULL;
1601         return &new->next;
1602 }
1603
1604 void print_commit_list(struct commit_list *list,
1605                        const char *format_cur,
1606                        const char *format_last)
1607 {
1608         for ( ; list; list = list->next) {
1609                 const char *format = list->next ? format_cur : format_last;
1610                 printf(format, sha1_to_hex(list->item->object.sha1));
1611         }
1612 }