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