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