commit.c

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