commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "pkt-line.h"
   5 #include "utf8.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "notes.h"
   9 #include "gpg-interface.h"
  10 #include "mergesort.h"
  11 #include "commit-slab.h"
  12 #include "prio-queue.h"
  13
  14 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  15
  16 int save_commit_buffer = 1;
  17
  18 const char *commit_type = "commit";
  19 static int commit_count;
  20
  21 static struct commit *check_commit(struct object *obj,
  22                                    const unsigned char *sha1,
  23                                    int quiet)
  24 {
  25         if (obj->type != OBJ_COMMIT) {
  26                 if (!quiet)
  27                         error("Object %s is a %s, not a commit",
  28                               sha1_to_hex(sha1), typename(obj->type));
  29                 return NULL;
  30         }
  31         return (struct commit *) obj;
  32 }
  33
  34 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  35                                               int quiet)
  36 {
  37         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  38
  39         if (!obj)
  40                 return NULL;
  41         return check_commit(obj, sha1, quiet);
  42 }
  43
  44 struct commit *lookup_commit_reference(const unsigned char *sha1)
  45 {
  46         return lookup_commit_reference_gently(sha1, 0);
  47 }
  48
  49 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  50 {
  51         struct commit *c = lookup_commit_reference(sha1);
  52         if (!c)
  53                 die(_("could not parse %s"), ref_name);
  54         if (hashcmp(sha1, c->object.sha1)) {
  55                 warning(_("%s %s is not a commit!"),
  56                         ref_name, sha1_to_hex(sha1));
  57         }
  58         return c;
  59 }
  60
  61 struct commit *lookup_commit(const unsigned char *sha1)
  62 {
  63         struct object *obj = lookup_object(sha1);
  64         if (!obj) {
  65                 struct commit *c = alloc_commit_node();
  66                 c->index = commit_count++;
  67                 return create_object(sha1, OBJ_COMMIT, c);
  68         }
  69         if (!obj->type)
  70                 obj->type = OBJ_COMMIT;
  71         return check_commit(obj, sha1, 0);
  72 }
  73
  74 struct commit *lookup_commit_reference_by_name(const char *name)
  75 {
  76         unsigned char sha1[20];
  77         struct commit *commit;
  78
  79         if (get_sha1_committish(name, sha1))
  80                 return NULL;
  81         commit = lookup_commit_reference(sha1);
  82         if (parse_commit(commit))
  83                 return NULL;
  84         return commit;
  85 }
  86
  87 static unsigned long parse_commit_date(const char *buf, const char *tail)
  88 {
  89         const char *dateptr;
  90
  91         if (buf + 6 >= tail)
  92                 return 0;
  93         if (memcmp(buf, "author", 6))
  94                 return 0;
  95         while (buf < tail && *buf++ != '\n')
  96                 /* nada */;
  97         if (buf + 9 >= tail)
  98                 return 0;
  99         if (memcmp(buf, "committer", 9))
 100                 return 0;
 101         while (buf < tail && *buf++ != '>')
 102                 /* nada */;
 103         if (buf >= tail)
 104                 return 0;
 105         dateptr = buf;
 106         while (buf < tail && *buf++ != '\n')
 107                 /* nada */;
 108         if (buf >= tail)
 109                 return 0;
 110         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 111         return strtoul(dateptr, NULL, 10);
 112 }
 113
 114 static struct commit_graft **commit_graft;
 115 static int commit_graft_alloc, commit_graft_nr;
 116
 117 static int commit_graft_pos(const unsigned char *sha1)
 118 {
 119         int lo, hi;
 120         lo = 0;
 121         hi = commit_graft_nr;
 122         while (lo < hi) {
 123                 int mi = (lo + hi) / 2;
 124                 struct commit_graft *graft = commit_graft[mi];
 125                 int cmp = hashcmp(sha1, graft->sha1);
 126                 if (!cmp)
 127                         return mi;
 128                 if (cmp < 0)
 129                         hi = mi;
 130                 else
 131                         lo = mi + 1;
 132         }
 133         return -lo - 1;
 134 }
 135
 136 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 137 {
 138         int pos = commit_graft_pos(graft->sha1);
 139
 140         if (0 <= pos) {
 141                 if (ignore_dups)
 142                         free(graft);
 143                 else {
 144                         free(commit_graft[pos]);
 145                         commit_graft[pos] = graft;
 146                 }
 147                 return 1;
 148         }
 149         pos = -pos - 1;
 150         if (commit_graft_alloc <= ++commit_graft_nr) {
 151                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 152                 commit_graft = xrealloc(commit_graft,
 153                                         sizeof(*commit_graft) *
 154                                         commit_graft_alloc);
 155         }
 156         if (pos < commit_graft_nr)
 157                 memmove(commit_graft + pos + 1,
 158                         commit_graft + pos,
 159                         (commit_graft_nr - pos - 1) *
 160                         sizeof(*commit_graft));
 161         commit_graft[pos] = graft;
 162         return 0;
 163 }
 164
 165 struct commit_graft *read_graft_line(char *buf, int len)
 166 {
 167         /* The format is just "Commit Parent1 Parent2 ...\n" */
 168         int i;
 169         struct commit_graft *graft = NULL;
 170
 171         while (len && isspace(buf[len-1]))
 172                 buf[--len] = '\0';
 173         if (buf[0] == '#' || buf[0] == '\0')
 174                 return NULL;
 175         if ((len + 1) % 41)
 176                 goto bad_graft_data;
 177         i = (len + 1) / 41 - 1;
 178         graft = xmalloc(sizeof(*graft) + 20 * i);
 179         graft->nr_parent = i;
 180         if (get_sha1_hex(buf, graft->sha1))
 181                 goto bad_graft_data;
 182         for (i = 40; i < len; i += 41) {
 183                 if (buf[i] != ' ')
 184                         goto bad_graft_data;
 185                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 186                         goto bad_graft_data;
 187         }
 188         return graft;
 189
 190 bad_graft_data:
 191         error("bad graft data: %s", buf);
 192         free(graft);
 193         return NULL;
 194 }
 195
 196 static int read_graft_file(const char *graft_file)
 197 {
 198         FILE *fp = fopen(graft_file, "r");
 199         char buf[1024];
 200         if (!fp)
 201                 return -1;
 202         while (fgets(buf, sizeof(buf), fp)) {
 203                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 204                 int len = strlen(buf);
 205                 struct commit_graft *graft = read_graft_line(buf, len);
 206                 if (!graft)
 207                         continue;
 208                 if (register_commit_graft(graft, 1))
 209                         error("duplicate graft data: %s", buf);
 210         }
 211         fclose(fp);
 212         return 0;
 213 }
 214
 215 static void prepare_commit_graft(void)
 216 {
 217         static int commit_graft_prepared;
 218         char *graft_file;
 219
 220         if (commit_graft_prepared)
 221                 return;
 222         graft_file = get_graft_file();
 223         read_graft_file(graft_file);
 224         /* make sure shallows are read */
 225         is_repository_shallow();
 226         commit_graft_prepared = 1;
 227 }
 228
 229 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 230 {
 231         int pos;
 232         prepare_commit_graft();
 233         pos = commit_graft_pos(sha1);
 234         if (pos < 0)
 235                 return NULL;
 236         return commit_graft[pos];
 237 }
 238
 239 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 240 {
 241         int i, ret;
 242         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 243                 ret = fn(commit_graft[i], cb_data);
 244         return ret;
 245 }
 246
 247 int unregister_shallow(const unsigned char *sha1)
 248 {
 249         int pos = commit_graft_pos(sha1);
 250         if (pos < 0)
 251                 return -1;
 252         if (pos + 1 < commit_graft_nr)
 253                 memmove(commit_graft + pos, commit_graft + pos + 1,
 254                                 sizeof(struct commit_graft *)
 255                                 * (commit_graft_nr - pos - 1));
 256         commit_graft_nr--;
 257         return 0;
 258 }
 259
 260 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 261 {
 262         const char *tail = buffer;
 263         const char *bufptr = buffer;
 264         unsigned char parent[20];
 265         struct commit_list **pptr;
 266         struct commit_graft *graft;
 267
 268         if (item->object.parsed)
 269                 return 0;
 270         item->object.parsed = 1;
 271         tail += size;
 272         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 273                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 274         if (get_sha1_hex(bufptr + 5, parent) < 0)
 275                 return error("bad tree pointer in commit %s",
 276                              sha1_to_hex(item->object.sha1));
 277         item->tree = lookup_tree(parent);
 278         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 279         pptr = &item->parents;
 280
 281         graft = lookup_commit_graft(item->object.sha1);
 282         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 283                 struct commit *new_parent;
 284
 285                 if (tail <= bufptr + 48 ||
 286                     get_sha1_hex(bufptr + 7, parent) ||
 287                     bufptr[47] != '\n')
 288                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 289                 bufptr += 48;
 290                 /*
 291                  * The clone is shallow if nr_parent < 0, and we must
 292                  * not traverse its real parents even when we unhide them.
 293                  */
 294                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 295                         continue;
 296                 new_parent = lookup_commit(parent);
 297                 if (new_parent)
 298                         pptr = &commit_list_insert(new_parent, pptr)->next;
 299         }
 300         if (graft) {
 301                 int i;
 302                 struct commit *new_parent;
 303                 for (i = 0; i < graft->nr_parent; i++) {
 304                         new_parent = lookup_commit(graft->parent[i]);
 305                         if (!new_parent)
 306                                 continue;
 307                         pptr = &commit_list_insert(new_parent, pptr)->next;
 308                 }
 309         }
 310         item->date = parse_commit_date(bufptr, tail);
 311
 312         return 0;
 313 }
 314
 315 int parse_commit(struct commit *item)
 316 {
 317         enum object_type type;
 318         void *buffer;
 319         unsigned long size;
 320         int ret;
 321
 322         if (!item)
 323                 return -1;
 324         if (item->object.parsed)
 325                 return 0;
 326         buffer = read_sha1_file(item->object.sha1, &type, &size);
 327         if (!buffer)
 328                 return error("Could not read %s",
 329                              sha1_to_hex(item->object.sha1));
 330         if (type != OBJ_COMMIT) {
 331                 free(buffer);
 332                 return error("Object %s not a commit",
 333                              sha1_to_hex(item->object.sha1));
 334         }
 335         ret = parse_commit_buffer(item, buffer, size);
 336         if (save_commit_buffer && !ret) {
 337                 item->buffer = buffer;
 338                 return 0;
 339         }
 340         free(buffer);
 341         return ret;
 342 }
 343
 344 void parse_commit_or_die(struct commit *item)
 345 {
 346         if (parse_commit(item))
 347                 die("unable to parse commit %s",
 348                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 349 }
 350
 351 int find_commit_subject(const char *commit_buffer, const char **subject)
 352 {
 353         const char *eol;
 354         const char *p = commit_buffer;
 355
 356         while (*p && (*p != '\n' || p[1] != '\n'))
 357                 p++;
 358         if (*p) {
 359                 p += 2;
 360                 for (eol = p; *eol && *eol != '\n'; eol++)
 361                         ; /* do nothing */
 362         } else
 363                 eol = p;
 364
 365         *subject = p;
 366
 367         return eol - p;
 368 }
 369
 370 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 371 {
 372         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 373         new_list->item = item;
 374         new_list->next = *list_p;
 375         *list_p = new_list;
 376         return new_list;
 377 }
 378
 379 unsigned commit_list_count(const struct commit_list *l)
 380 {
 381         unsigned c = 0;
 382         for (; l; l = l->next )
 383                 c++;
 384         return c;
 385 }
 386
 387 struct commit_list *copy_commit_list(struct commit_list *list)
 388 {
 389         struct commit_list *head = NULL;
 390         struct commit_list **pp = &head;
 391         while (list) {
 392                 struct commit_list *new;
 393                 new = xmalloc(sizeof(struct commit_list));
 394                 new->item = list->item;
 395                 new->next = NULL;
 396                 *pp = new;
 397                 pp = &new->next;
 398                 list = list->next;
 399         }
 400         return head;
 401 }
 402
 403 void free_commit_list(struct commit_list *list)
 404 {
 405         while (list) {
 406                 struct commit_list *temp = list;
 407                 list = temp->next;
 408                 free(temp);
 409         }
 410 }
 411
 412 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 413 {
 414         struct commit_list **pp = list;
 415         struct commit_list *p;
 416         while ((p = *pp) != NULL) {
 417                 if (p->item->date < item->date) {
 418                         break;
 419                 }
 420                 pp = &p->next;
 421         }
 422         return commit_list_insert(item, pp);
 423 }
 424
 425 static int commit_list_compare_by_date(const void *a, const void *b)
 426 {
 427         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 428         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 429         if (a_date < b_date)
 430                 return 1;
 431         if (a_date > b_date)
 432                 return -1;
 433         return 0;
 434 }
 435
 436 static void *commit_list_get_next(const void *a)
 437 {
 438         return ((const struct commit_list *)a)->next;
 439 }
 440
 441 static void commit_list_set_next(void *a, void *next)
 442 {
 443         ((struct commit_list *)a)->next = next;
 444 }
 445
 446 void commit_list_sort_by_date(struct commit_list **list)
 447 {
 448         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 449                                 commit_list_compare_by_date);
 450 }
 451
 452 struct commit *pop_most_recent_commit(struct commit_list **list,
 453                                       unsigned int mark)
 454 {
 455         struct commit *ret = (*list)->item;
 456         struct commit_list *parents = ret->parents;
 457         struct commit_list *old = *list;
 458
 459         *list = (*list)->next;
 460         free(old);
 461
 462         while (parents) {
 463                 struct commit *commit = parents->item;
 464                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 465                         commit->object.flags |= mark;
 466                         commit_list_insert_by_date(commit, list);
 467                 }
 468                 parents = parents->next;
 469         }
 470         return ret;
 471 }
 472
 473 static void clear_commit_marks_1(struct commit_list **plist,
 474                                  struct commit *commit, unsigned int mark)
 475 {
 476         while (commit) {
 477                 struct commit_list *parents;
 478
 479                 if (!(mark & commit->object.flags))
 480                         return;
 481
 482                 commit->object.flags &= ~mark;
 483
 484                 parents = commit->parents;
 485                 if (!parents)
 486                         return;
 487
 488                 while ((parents = parents->next))
 489                         commit_list_insert(parents->item, plist);
 490
 491                 commit = commit->parents->item;
 492         }
 493 }
 494
 495 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 496 {
 497         struct commit_list *list = NULL;
 498
 499         while (nr--) {
 500                 commit_list_insert(*commit, &list);
 501                 commit++;
 502         }
 503         while (list)
 504                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 505 }
 506
 507 void clear_commit_marks(struct commit *commit, unsigned int mark)
 508 {
 509         clear_commit_marks_many(1, &commit, mark);
 510 }
 511
 512 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 513 {
 514         struct object *object;
 515         struct commit *commit;
 516         unsigned int i;
 517
 518         for (i = 0; i < a->nr; i++) {
 519                 object = a->objects[i].item;
 520                 commit = lookup_commit_reference_gently(object->sha1, 1);
 521                 if (commit)
 522                         clear_commit_marks(commit, mark);
 523         }
 524 }
 525
 526 struct commit *pop_commit(struct commit_list **stack)
 527 {
 528         struct commit_list *top = *stack;
 529         struct commit *item = top ? top->item : NULL;
 530
 531         if (top) {
 532                 *stack = top->next;
 533                 free(top);
 534         }
 535         return item;
 536 }
 537
 538 /*
 539  * Topological sort support
 540  */
 541
 542 /* count number of children that have not been emitted */
 543 define_commit_slab(indegree_slab, int);
 544
 545 /* record author-date for each commit object */
 546 define_commit_slab(author_date_slab, unsigned long);
 547
 548 static void record_author_date(struct author_date_slab *author_date,
 549                                struct commit *commit)
 550 {
 551         const char *buf, *line_end;
 552         char *buffer = NULL;
 553         struct ident_split ident;
 554         char *date_end;
 555         unsigned long date;
 556
 557         if (!commit->buffer) {
 558                 unsigned long size;
 559                 enum object_type type;
 560                 buffer = read_sha1_file(commit->object.sha1, &type, &size);
 561                 if (!buffer)
 562                         return;
 563         }
 564
 565         for (buf = commit->buffer ? commit->buffer : buffer;
 566              buf;
 567              buf = line_end + 1) {
 568                 line_end = strchrnul(buf, '\n');
 569                 if (!starts_with(buf, "author ")) {
 570                         if (!line_end[0] || line_end[1] == '\n')
 571                                 return; /* end of header */
 572                         continue;
 573                 }
 574                 if (split_ident_line(&ident,
 575                                      buf + strlen("author "),
 576                                      line_end - (buf + strlen("author "))) ||
 577                     !ident.date_begin || !ident.date_end)
 578                         goto fail_exit; /* malformed "author" line */
 579                 break;
 580         }
 581
 582         date = strtoul(ident.date_begin, &date_end, 10);
 583         if (date_end != ident.date_end)
 584                 goto fail_exit; /* malformed date */
 585         *(author_date_slab_at(author_date, commit)) = date;
 586
 587 fail_exit:
 588         free(buffer);
 589 }
 590
 591 static int compare_commits_by_author_date(const void *a_, const void *b_,
 592                                           void *cb_data)
 593 {
 594         const struct commit *a = a_, *b = b_;
 595         struct author_date_slab *author_date = cb_data;
 596         unsigned long a_date = *(author_date_slab_at(author_date, a));
 597         unsigned long b_date = *(author_date_slab_at(author_date, b));
 598
 599         /* newer commits with larger date first */
 600         if (a_date < b_date)
 601                 return 1;
 602         else if (a_date > b_date)
 603                 return -1;
 604         return 0;
 605 }
 606
 607 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 608 {
 609         const struct commit *a = a_, *b = b_;
 610         /* newer commits with larger date first */
 611         if (a->date < b->date)
 612                 return 1;
 613         else if (a->date > b->date)
 614                 return -1;
 615         return 0;
 616 }
 617
 618 /*
 619  * Performs an in-place topological sort on the list supplied.
 620  */
 621 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 622 {
 623         struct commit_list *next, *orig = *list;
 624         struct commit_list **pptr;
 625         struct indegree_slab indegree;
 626         struct prio_queue queue;
 627         struct commit *commit;
 628         struct author_date_slab author_date;
 629
 630         if (!orig)
 631                 return;
 632         *list = NULL;
 633
 634         init_indegree_slab(&indegree);
 635         memset(&queue, '\0', sizeof(queue));
 636
 637         switch (sort_order) {
 638         default: /* REV_SORT_IN_GRAPH_ORDER */
 639                 queue.compare = NULL;
 640                 break;
 641         case REV_SORT_BY_COMMIT_DATE:
 642                 queue.compare = compare_commits_by_commit_date;
 643                 break;
 644         case REV_SORT_BY_AUTHOR_DATE:
 645                 init_author_date_slab(&author_date);
 646                 queue.compare = compare_commits_by_author_date;
 647                 queue.cb_data = &author_date;
 648                 break;
 649         }
 650
 651         /* Mark them and clear the indegree */
 652         for (next = orig; next; next = next->next) {
 653                 struct commit *commit = next->item;
 654                 *(indegree_slab_at(&indegree, commit)) = 1;
 655                 /* also record the author dates, if needed */
 656                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 657                         record_author_date(&author_date, commit);
 658         }
 659
 660         /* update the indegree */
 661         for (next = orig; next; next = next->next) {
 662                 struct commit_list *parents = next->item->parents;
 663                 while (parents) {
 664                         struct commit *parent = parents->item;
 665                         int *pi = indegree_slab_at(&indegree, parent);
 666
 667                         if (*pi)
 668                                 (*pi)++;
 669                         parents = parents->next;
 670                 }
 671         }
 672
 673         /*
 674          * find the tips
 675          *
 676          * tips are nodes not reachable from any other node in the list
 677          *
 678          * the tips serve as a starting set for the work queue.
 679          */
 680         for (next = orig; next; next = next->next) {
 681                 struct commit *commit = next->item;
 682
 683                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 684                         prio_queue_put(&queue, commit);
 685         }
 686
 687         /*
 688          * This is unfortunate; the initial tips need to be shown
 689          * in the order given from the revision traversal machinery.
 690          */
 691         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 692                 prio_queue_reverse(&queue);
 693
 694         /* We no longer need the commit list */
 695         free_commit_list(orig);
 696
 697         pptr = list;
 698         *list = NULL;
 699         while ((commit = prio_queue_get(&queue)) != NULL) {
 700                 struct commit_list *parents;
 701
 702                 for (parents = commit->parents; parents ; parents = parents->next) {
 703                         struct commit *parent = parents->item;
 704                         int *pi = indegree_slab_at(&indegree, parent);
 705
 706                         if (!*pi)
 707                                 continue;
 708
 709                         /*
 710                          * parents are only enqueued for emission
 711                          * when all their children have been emitted thereby
 712                          * guaranteeing topological order.
 713                          */
 714                         if (--(*pi) == 1)
 715                                 prio_queue_put(&queue, parent);
 716                 }
 717                 /*
 718                  * all children of commit have already been
 719                  * emitted. we can emit it now.
 720                  */
 721                 *(indegree_slab_at(&indegree, commit)) = 0;
 722
 723                 pptr = &commit_list_insert(commit, pptr)->next;
 724         }
 725
 726         clear_indegree_slab(&indegree);
 727         clear_prio_queue(&queue);
 728         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 729                 clear_author_date_slab(&author_date);
 730 }
 731
 732 /* merge-base stuff */
 733
 734 /* bits #0..15 in revision.h */
 735 #define PARENT1         (1u<<16)
 736 #define PARENT2         (1u<<17)
 737 #define STALE           (1u<<18)
 738 #define RESULT          (1u<<19)
 739
 740 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 741
 742 static struct commit *interesting(struct commit_list *list)
 743 {
 744         while (list) {
 745                 struct commit *commit = list->item;
 746                 list = list->next;
 747                 if (commit->object.flags & STALE)
 748                         continue;
 749                 return commit;
 750         }
 751         return NULL;
 752 }
 753
 754 /* all input commits in one and twos[] must have been parsed! */
 755 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 756 {
 757         struct commit_list *list = NULL;
 758         struct commit_list *result = NULL;
 759         int i;
 760
 761         one->object.flags |= PARENT1;
 762         commit_list_insert_by_date(one, &list);
 763         if (!n)
 764                 return list;
 765         for (i = 0; i < n; i++) {
 766                 twos[i]->object.flags |= PARENT2;
 767                 commit_list_insert_by_date(twos[i], &list);
 768         }
 769
 770         while (interesting(list)) {
 771                 struct commit *commit;
 772                 struct commit_list *parents;
 773                 struct commit_list *next;
 774                 int flags;
 775
 776                 commit = list->item;
 777                 next = list->next;
 778                 free(list);
 779                 list = next;
 780
 781                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 782                 if (flags == (PARENT1 | PARENT2)) {
 783                         if (!(commit->object.flags & RESULT)) {
 784                                 commit->object.flags |= RESULT;
 785                                 commit_list_insert_by_date(commit, &result);
 786                         }
 787                         /* Mark parents of a found merge stale */
 788                         flags |= STALE;
 789                 }
 790                 parents = commit->parents;
 791                 while (parents) {
 792                         struct commit *p = parents->item;
 793                         parents = parents->next;
 794                         if ((p->object.flags & flags) == flags)
 795                                 continue;
 796                         if (parse_commit(p))
 797                                 return NULL;
 798                         p->object.flags |= flags;
 799                         commit_list_insert_by_date(p, &list);
 800                 }
 801         }
 802
 803         free_commit_list(list);
 804         return result;
 805 }
 806
 807 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 808 {
 809         struct commit_list *list = NULL;
 810         struct commit_list *result = NULL;
 811         int i;
 812
 813         for (i = 0; i < n; i++) {
 814                 if (one == twos[i])
 815                         /*
 816                          * We do not mark this even with RESULT so we do not
 817                          * have to clean it up.
 818                          */
 819                         return commit_list_insert(one, &result);
 820         }
 821
 822         if (parse_commit(one))
 823                 return NULL;
 824         for (i = 0; i < n; i++) {
 825                 if (parse_commit(twos[i]))
 826                         return NULL;
 827         }
 828
 829         list = paint_down_to_common(one, n, twos);
 830
 831         while (list) {
 832                 struct commit_list *next = list->next;
 833                 if (!(list->item->object.flags & STALE))
 834                         commit_list_insert_by_date(list->item, &result);
 835                 free(list);
 836                 list = next;
 837         }
 838         return result;
 839 }
 840
 841 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 842 {
 843         struct commit_list *i, *j, *k, *ret = NULL;
 844         struct commit_list **pptr = &ret;
 845
 846         for (i = in; i; i = i->next) {
 847                 if (!ret)
 848                         pptr = &commit_list_insert(i->item, pptr)->next;
 849                 else {
 850                         struct commit_list *new = NULL, *end = NULL;
 851
 852                         for (j = ret; j; j = j->next) {
 853                                 struct commit_list *bases;
 854                                 bases = get_merge_bases(i->item, j->item, 1);
 855                                 if (!new)
 856                                         new = bases;
 857                                 else
 858                                         end->next = bases;
 859                                 for (k = bases; k; k = k->next)
 860                                         end = k;
 861                         }
 862                         ret = new;
 863                 }
 864         }
 865         return ret;
 866 }
 867
 868 static int remove_redundant(struct commit **array, int cnt)
 869 {
 870         /*
 871          * Some commit in the array may be an ancestor of
 872          * another commit.  Move such commit to the end of
 873          * the array, and return the number of commits that
 874          * are independent from each other.
 875          */
 876         struct commit **work;
 877         unsigned char *redundant;
 878         int *filled_index;
 879         int i, j, filled;
 880
 881         work = xcalloc(cnt, sizeof(*work));
 882         redundant = xcalloc(cnt, 1);
 883         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 884
 885         for (i = 0; i < cnt; i++)
 886                 parse_commit(array[i]);
 887         for (i = 0; i < cnt; i++) {
 888                 struct commit_list *common;
 889
 890                 if (redundant[i])
 891                         continue;
 892                 for (j = filled = 0; j < cnt; j++) {
 893                         if (i == j || redundant[j])
 894                                 continue;
 895                         filled_index[filled] = j;
 896                         work[filled++] = array[j];
 897                 }
 898                 common = paint_down_to_common(array[i], filled, work);
 899                 if (array[i]->object.flags & PARENT2)
 900                         redundant[i] = 1;
 901                 for (j = 0; j < filled; j++)
 902                         if (work[j]->object.flags & PARENT1)
 903                                 redundant[filled_index[j]] = 1;
 904                 clear_commit_marks(array[i], all_flags);
 905                 for (j = 0; j < filled; j++)
 906                         clear_commit_marks(work[j], all_flags);
 907                 free_commit_list(common);
 908         }
 909
 910         /* Now collect the result */
 911         memcpy(work, array, sizeof(*array) * cnt);
 912         for (i = filled = 0; i < cnt; i++)
 913                 if (!redundant[i])
 914                         array[filled++] = work[i];
 915         for (j = filled, i = 0; i < cnt; i++)
 916                 if (redundant[i])
 917                         array[j++] = work[i];
 918         free(work);
 919         free(redundant);
 920         free(filled_index);
 921         return filled;
 922 }
 923
 924 struct commit_list *get_merge_bases_many(struct commit *one,
 925                                          int n,
 926                                          struct commit **twos,
 927                                          int cleanup)
 928 {
 929         struct commit_list *list;
 930         struct commit **rslt;
 931         struct commit_list *result;
 932         int cnt, i;
 933
 934         result = merge_bases_many(one, n, twos);
 935         for (i = 0; i < n; i++) {
 936                 if (one == twos[i])
 937                         return result;
 938         }
 939         if (!result || !result->next) {
 940                 if (cleanup) {
 941                         clear_commit_marks(one, all_flags);
 942                         clear_commit_marks_many(n, twos, all_flags);
 943                 }
 944                 return result;
 945         }
 946
 947         /* There are more than one */
 948         cnt = 0;
 949         list = result;
 950         while (list) {
 951                 list = list->next;
 952                 cnt++;
 953         }
 954         rslt = xcalloc(cnt, sizeof(*rslt));
 955         for (list = result, i = 0; list; list = list->next)
 956                 rslt[i++] = list->item;
 957         free_commit_list(result);
 958
 959         clear_commit_marks(one, all_flags);
 960         clear_commit_marks_many(n, twos, all_flags);
 961
 962         cnt = remove_redundant(rslt, cnt);
 963         result = NULL;
 964         for (i = 0; i < cnt; i++)
 965                 commit_list_insert_by_date(rslt[i], &result);
 966         free(rslt);
 967         return result;
 968 }
 969
 970 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 971                                     int cleanup)
 972 {
 973         return get_merge_bases_many(one, 1, &two, cleanup);
 974 }
 975
 976 /*
 977  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 978  */
 979 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 980 {
 981         if (!with_commit)
 982                 return 1;
 983         while (with_commit) {
 984                 struct commit *other;
 985
 986                 other = with_commit->item;
 987                 with_commit = with_commit->next;
 988                 if (in_merge_bases(other, commit))
 989                         return 1;
 990         }
 991         return 0;
 992 }
 993
 994 /*
 995  * Is "commit" an ancestor of one of the "references"?
 996  */
 997 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 998 {
 999         struct commit_list *bases;
1000         int ret = 0, i;
1001
1002         if (parse_commit(commit))
1003                 return ret;
1004         for (i = 0; i < nr_reference; i++)
1005                 if (parse_commit(reference[i]))
1006                         return ret;
1007
1008         bases = paint_down_to_common(commit, nr_reference, reference);
1009         if (commit->object.flags & PARENT2)
1010                 ret = 1;
1011         clear_commit_marks(commit, all_flags);
1012         clear_commit_marks_many(nr_reference, reference, all_flags);
1013         free_commit_list(bases);
1014         return ret;
1015 }
1016
1017 /*
1018  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1019  */
1020 int in_merge_bases(struct commit *commit, struct commit *reference)
1021 {
1022         return in_merge_bases_many(commit, 1, &reference);
1023 }
1024
1025 struct commit_list *reduce_heads(struct commit_list *heads)
1026 {
1027         struct commit_list *p;
1028         struct commit_list *result = NULL, **tail = &result;
1029         struct commit **array;
1030         int num_head, i;
1031
1032         if (!heads)
1033                 return NULL;
1034
1035         /* Uniquify */
1036         for (p = heads; p; p = p->next)
1037                 p->item->object.flags &= ~STALE;
1038         for (p = heads, num_head = 0; p; p = p->next) {
1039                 if (p->item->object.flags & STALE)
1040                         continue;
1041                 p->item->object.flags |= STALE;
1042                 num_head++;
1043         }
1044         array = xcalloc(sizeof(*array), num_head);
1045         for (p = heads, i = 0; p; p = p->next) {
1046                 if (p->item->object.flags & STALE) {
1047                         array[i++] = p->item;
1048                         p->item->object.flags &= ~STALE;
1049                 }
1050         }
1051         num_head = remove_redundant(array, num_head);
1052         for (i = 0; i < num_head; i++)
1053                 tail = &commit_list_insert(array[i], tail)->next;
1054         return result;
1055 }
1056
1057 static const char gpg_sig_header[] = "gpgsig";
1058 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1059
1060 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1061 {
1062         struct strbuf sig = STRBUF_INIT;
1063         int inspos, copypos;
1064
1065         /* find the end of the header */
1066         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1067
1068         if (!keyid || !*keyid)
1069                 keyid = get_signing_key();
1070         if (sign_buffer(buf, &sig, keyid)) {
1071                 strbuf_release(&sig);
1072                 return -1;
1073         }
1074
1075         for (copypos = 0; sig.buf[copypos]; ) {
1076                 const char *bol = sig.buf + copypos;
1077                 const char *eol = strchrnul(bol, '\n');
1078                 int len = (eol - bol) + !!*eol;
1079
1080                 if (!copypos) {
1081                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1082                         inspos += gpg_sig_header_len;
1083                 }
1084                 strbuf_insert(buf, inspos++, " ", 1);
1085                 strbuf_insert(buf, inspos, bol, len);
1086                 inspos += len;
1087                 copypos += len;
1088         }
1089         strbuf_release(&sig);
1090         return 0;
1091 }
1092
1093 int parse_signed_commit(const unsigned char *sha1,
1094                         struct strbuf *payload, struct strbuf *signature)
1095 {
1096         unsigned long size;
1097         enum object_type type;
1098         char *buffer = read_sha1_file(sha1, &type, &size);
1099         int in_signature, saw_signature = -1;
1100         char *line, *tail;
1101
1102         if (!buffer || type != OBJ_COMMIT)
1103                 goto cleanup;
1104
1105         line = buffer;
1106         tail = buffer + size;
1107         in_signature = 0;
1108         saw_signature = 0;
1109         while (line < tail) {
1110                 const char *sig = NULL;
1111                 char *next = memchr(line, '\n', tail - line);
1112
1113                 next = next ? next + 1 : tail;
1114                 if (in_signature && line[0] == ' ')
1115                         sig = line + 1;
1116                 else if (starts_with(line, gpg_sig_header) &&
1117                          line[gpg_sig_header_len] == ' ')
1118                         sig = line + gpg_sig_header_len + 1;
1119                 if (sig) {
1120                         strbuf_add(signature, sig, next - sig);
1121                         saw_signature = 1;
1122                         in_signature = 1;
1123                 } else {
1124                         if (*line == '\n')
1125                                 /* dump the whole remainder of the buffer */
1126                                 next = tail;
1127                         strbuf_add(payload, line, next - line);
1128                         in_signature = 0;
1129                 }
1130                 line = next;
1131         }
1132  cleanup:
1133         free(buffer);
1134         return saw_signature;
1135 }
1136
1137 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1138 {
1139         struct merge_remote_desc *desc;
1140         struct commit_extra_header *mergetag;
1141         char *buf;
1142         unsigned long size, len;
1143         enum object_type type;
1144
1145         desc = merge_remote_util(parent);
1146         if (!desc || !desc->obj)
1147                 return;
1148         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1149         if (!buf || type != OBJ_TAG)
1150                 goto free_return;
1151         len = parse_signature(buf, size);
1152         if (size == len)
1153                 goto free_return;
1154         /*
1155          * We could verify this signature and either omit the tag when
1156          * it does not validate, but the integrator may not have the
1157          * public key of the signer of the tag he is merging, while a
1158          * later auditor may have it while auditing, so let's not run
1159          * verify-signed-buffer here for now...
1160          *
1161          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1162          *      warn("warning: signed tag unverified.");
1163          */
1164         mergetag = xcalloc(1, sizeof(*mergetag));
1165         mergetag->key = xstrdup("mergetag");
1166         mergetag->value = buf;
1167         mergetag->len = size;
1168
1169         **tail = mergetag;
1170         *tail = &mergetag->next;
1171         return;
1172
1173 free_return:
1174         free(buf);
1175 }
1176
1177 static struct {
1178         char result;
1179         const char *check;
1180 } sigcheck_gpg_status[] = {
1181         { 'G', "\n[GNUPG:] GOODSIG " },
1182         { 'B', "\n[GNUPG:] BADSIG " },
1183         { 'U', "\n[GNUPG:] TRUST_NEVER" },
1184         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1185 };
1186
1187 static void parse_gpg_output(struct signature_check *sigc)
1188 {
1189         const char *buf = sigc->gpg_status;
1190         int i;
1191
1192         /* Iterate over all search strings */
1193         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1194                 const char *found, *next;
1195
1196                 if (starts_with(buf, sigcheck_gpg_status[i].check + 1)) {
1197                         /* At the very beginning of the buffer */
1198                         found = buf + strlen(sigcheck_gpg_status[i].check + 1);
1199                 } else {
1200                         found = strstr(buf, sigcheck_gpg_status[i].check);
1201                         if (!found)
1202                                 continue;
1203                         found += strlen(sigcheck_gpg_status[i].check);
1204                 }
1205                 sigc->result = sigcheck_gpg_status[i].result;
1206                 /* The trust messages are not followed by key/signer information */
1207                 if (sigc->result != 'U') {
1208                         sigc->key = xmemdupz(found, 16);
1209                         found += 17;
1210                         next = strchrnul(found, '\n');
1211                         sigc->signer = xmemdupz(found, next - found);
1212                 }
1213         }
1214 }
1215
1216 void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1217 {
1218         struct strbuf payload = STRBUF_INIT;
1219         struct strbuf signature = STRBUF_INIT;
1220         struct strbuf gpg_output = STRBUF_INIT;
1221         struct strbuf gpg_status = STRBUF_INIT;
1222         int status;
1223
1224         sigc->result = 'N';
1225
1226         if (parse_signed_commit(commit->object.sha1,
1227                                 &payload, &signature) <= 0)
1228                 goto out;
1229         status = verify_signed_buffer(payload.buf, payload.len,
1230                                       signature.buf, signature.len,
1231                                       &gpg_output, &gpg_status);
1232         if (status && !gpg_output.len)
1233                 goto out;
1234         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1235         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1236         parse_gpg_output(sigc);
1237
1238  out:
1239         strbuf_release(&gpg_status);
1240         strbuf_release(&gpg_output);
1241         strbuf_release(&payload);
1242         strbuf_release(&signature);
1243 }
1244
1245
1246
1247 void append_merge_tag_headers(struct commit_list *parents,
1248                               struct commit_extra_header ***tail)
1249 {
1250         while (parents) {
1251                 struct commit *parent = parents->item;
1252                 handle_signed_tag(parent, tail);
1253                 parents = parents->next;
1254         }
1255 }
1256
1257 static void add_extra_header(struct strbuf *buffer,
1258                              struct commit_extra_header *extra)
1259 {
1260         strbuf_addstr(buffer, extra->key);
1261         if (extra->len)
1262                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1263         else
1264                 strbuf_addch(buffer, '\n');
1265 }
1266
1267 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1268                                                       const char **exclude)
1269 {
1270         struct commit_extra_header *extra = NULL;
1271         unsigned long size;
1272         enum object_type type;
1273         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1274         if (buffer && type == OBJ_COMMIT)
1275                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1276         free(buffer);
1277         return extra;
1278 }
1279
1280 static inline int standard_header_field(const char *field, size_t len)
1281 {
1282         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1283                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1284                 (len == 6 && !memcmp(field, "author ", 7)) ||
1285                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1286                 (len == 8 && !memcmp(field, "encoding ", 9)));
1287 }
1288
1289 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1290 {
1291         if (!exclude)
1292                 return 0;
1293
1294         while (*exclude) {
1295                 size_t xlen = strlen(*exclude);
1296                 if (len == xlen &&
1297                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1298                         return 1;
1299                 exclude++;
1300         }
1301         return 0;
1302 }
1303
1304 static struct commit_extra_header *read_commit_extra_header_lines(
1305         const char *buffer, size_t size,
1306         const char **exclude)
1307 {
1308         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1309         const char *line, *next, *eof, *eob;
1310         struct strbuf buf = STRBUF_INIT;
1311
1312         for (line = buffer, eob = line + size;
1313              line < eob && *line != '\n';
1314              line = next) {
1315                 next = memchr(line, '\n', eob - line);
1316                 next = next ? next + 1 : eob;
1317                 if (*line == ' ') {
1318                         /* continuation */
1319                         if (it)
1320                                 strbuf_add(&buf, line + 1, next - (line + 1));
1321                         continue;
1322                 }
1323                 if (it)
1324                         it->value = strbuf_detach(&buf, &it->len);
1325                 strbuf_reset(&buf);
1326                 it = NULL;
1327
1328                 eof = strchr(line, ' ');
1329                 if (next <= eof)
1330                         eof = next;
1331
1332                 if (standard_header_field(line, eof - line) ||
1333                     excluded_header_field(line, eof - line, exclude))
1334                         continue;
1335
1336                 it = xcalloc(1, sizeof(*it));
1337                 it->key = xmemdupz(line, eof-line);
1338                 *tail = it;
1339                 tail = &it->next;
1340                 if (eof + 1 < next)
1341                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1342         }
1343         if (it)
1344                 it->value = strbuf_detach(&buf, &it->len);
1345         return extra;
1346 }
1347
1348 void free_commit_extra_headers(struct commit_extra_header *extra)
1349 {
1350         while (extra) {
1351                 struct commit_extra_header *next = extra->next;
1352                 free(extra->key);
1353                 free(extra->value);
1354                 free(extra);
1355                 extra = next;
1356         }
1357 }
1358
1359 int commit_tree(const struct strbuf *msg, unsigned char *tree,
1360                 struct commit_list *parents, unsigned char *ret,
1361                 const char *author, const char *sign_commit)
1362 {
1363         struct commit_extra_header *extra = NULL, **tail = &extra;
1364         int result;
1365
1366         append_merge_tag_headers(parents, &tail);
1367         result = commit_tree_extended(msg, tree, parents, ret,
1368                                       author, sign_commit, extra);
1369         free_commit_extra_headers(extra);
1370         return result;
1371 }
1372
1373 static int find_invalid_utf8(const char *buf, int len)
1374 {
1375         int offset = 0;
1376         static const unsigned int max_codepoint[] = {
1377                 0x7f, 0x7ff, 0xffff, 0x10ffff
1378         };
1379
1380         while (len) {
1381                 unsigned char c = *buf++;
1382                 int bytes, bad_offset;
1383                 unsigned int codepoint;
1384                 unsigned int min_val, max_val;
1385
1386                 len--;
1387                 offset++;
1388
1389                 /* Simple US-ASCII? No worries. */
1390                 if (c < 0x80)
1391                         continue;
1392
1393                 bad_offset = offset-1;
1394
1395                 /*
1396                  * Count how many more high bits set: that's how
1397                  * many more bytes this sequence should have.
1398                  */
1399                 bytes = 0;
1400                 while (c & 0x40) {
1401                         c <<= 1;
1402                         bytes++;
1403                 }
1404
1405                 /*
1406                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1407                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1408                  */
1409                 if (bytes < 1 || 3 < bytes)
1410                         return bad_offset;
1411
1412                 /* Do we *have* that many bytes? */
1413                 if (len < bytes)
1414                         return bad_offset;
1415
1416                 /*
1417                  * Place the encoded bits at the bottom of the value and compute the
1418                  * valid range.
1419                  */
1420                 codepoint = (c & 0x7f) >> bytes;
1421                 min_val = max_codepoint[bytes-1] + 1;
1422                 max_val = max_codepoint[bytes];
1423
1424                 offset += bytes;
1425                 len -= bytes;
1426
1427                 /* And verify that they are good continuation bytes */
1428                 do {
1429                         codepoint <<= 6;
1430                         codepoint |= *buf & 0x3f;
1431                         if ((*buf++ & 0xc0) != 0x80)
1432                                 return bad_offset;
1433                 } while (--bytes);
1434
1435                 /* Reject codepoints that are out of range for the sequence length. */
1436                 if (codepoint < min_val || codepoint > max_val)
1437                         return bad_offset;
1438                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1439                 if ((codepoint & 0x1ff800) == 0xd800)
1440                         return bad_offset;
1441                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1442                 if ((codepoint & 0xfffe) == 0xfffe)
1443                         return bad_offset;
1444                 /* So are anything in the range U+FDD0..U+FDEF. */
1445                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1446                         return bad_offset;
1447         }
1448         return -1;
1449 }
1450
1451 /*
1452  * This verifies that the buffer is in proper utf8 format.
1453  *
1454  * If it isn't, it assumes any non-utf8 characters are Latin1,
1455  * and does the conversion.
1456  */
1457 static int verify_utf8(struct strbuf *buf)
1458 {
1459         int ok = 1;
1460         long pos = 0;
1461
1462         for (;;) {
1463                 int bad;
1464                 unsigned char c;
1465                 unsigned char replace[2];
1466
1467                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1468                 if (bad < 0)
1469                         return ok;
1470                 pos += bad;
1471                 ok = 0;
1472                 c = buf->buf[pos];
1473                 strbuf_remove(buf, pos, 1);
1474
1475                 /* We know 'c' must be in the range 128-255 */
1476                 replace[0] = 0xc0 + (c >> 6);
1477                 replace[1] = 0x80 + (c & 0x3f);
1478                 strbuf_insert(buf, pos, replace, 2);
1479                 pos += 2;
1480         }
1481 }
1482
1483 static const char commit_utf8_warn[] =
1484 "Warning: commit message did not conform to UTF-8.\n"
1485 "You may want to amend it after fixing the message, or set the config\n"
1486 "variable i18n.commitencoding to the encoding your project uses.\n";
1487
1488 int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1489                          struct commit_list *parents, unsigned char *ret,
1490                          const char *author, const char *sign_commit,
1491                          struct commit_extra_header *extra)
1492 {
1493         int result;
1494         int encoding_is_utf8;
1495         struct strbuf buffer;
1496
1497         assert_sha1_type(tree, OBJ_TREE);
1498
1499         if (memchr(msg->buf, '\0', msg->len))
1500                 return error("a NUL byte in commit log message not allowed.");
1501
1502         /* Not having i18n.commitencoding is the same as having utf-8 */
1503         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1504
1505         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1506         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1507
1508         /*
1509          * NOTE! This ordering means that the same exact tree merged with a
1510          * different order of parents will be a _different_ changeset even
1511          * if everything else stays the same.
1512          */
1513         while (parents) {
1514                 struct commit_list *next = parents->next;
1515                 struct commit *parent = parents->item;
1516
1517                 strbuf_addf(&buffer, "parent %s\n",
1518                             sha1_to_hex(parent->object.sha1));
1519                 free(parents);
1520                 parents = next;
1521         }
1522
1523         /* Person/date information */
1524         if (!author)
1525                 author = git_author_info(IDENT_STRICT);
1526         strbuf_addf(&buffer, "author %s\n", author);
1527         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1528         if (!encoding_is_utf8)
1529                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1530
1531         while (extra) {
1532                 add_extra_header(&buffer, extra);
1533                 extra = extra->next;
1534         }
1535         strbuf_addch(&buffer, '\n');
1536
1537         /* And add the comment */
1538         strbuf_addbuf(&buffer, msg);
1539
1540         /* And check the encoding */
1541         if (encoding_is_utf8 && !verify_utf8(&buffer))
1542                 fprintf(stderr, commit_utf8_warn);
1543
1544         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1545                 return -1;
1546
1547         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1548         strbuf_release(&buffer);
1549         return result;
1550 }
1551
1552 struct commit *get_merge_parent(const char *name)
1553 {
1554         struct object *obj;
1555         struct commit *commit;
1556         unsigned char sha1[20];
1557         if (get_sha1(name, sha1))
1558                 return NULL;
1559         obj = parse_object(sha1);
1560         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1561         if (commit && !commit->util) {
1562                 struct merge_remote_desc *desc;
1563                 desc = xmalloc(sizeof(*desc));
1564                 desc->obj = obj;
1565                 desc->name = strdup(name);
1566                 commit->util = desc;
1567         }
1568         return commit;
1569 }
1570
1571 /*
1572  * Append a commit to the end of the commit_list.
1573  *
1574  * next starts by pointing to the variable that holds the head of an
1575  * empty commit_list, and is updated to point to the "next" field of
1576  * the last item on the list as new commits are appended.
1577  *
1578  * Usage example:
1579  *
1580  *     struct commit_list *list;
1581  *     struct commit_list **next = &list;
1582  *
1583  *     next = commit_list_append(c1, next);
1584  *     next = commit_list_append(c2, next);
1585  *     assert(commit_list_count(list) == 2);
1586  *     return list;
1587  */
1588 struct commit_list **commit_list_append(struct commit *commit,
1589                                         struct commit_list **next)
1590 {
1591         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1592         new->item = commit;
1593         *next = new;
1594         new->next = NULL;
1595         return &new->next;
1596 }
1597
1598 void print_commit_list(struct commit_list *list,
1599                        const char *format_cur,
1600                        const char *format_last)
1601 {
1602         for ( ; list; list = list->next) {
1603                 const char *format = list->next ? format_cur : format_last;
1604                 printf(format, sha1_to_hex(list->item->object.sha1));
1605         }
1606 }