commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "pkt-line.h"
   5 #include "utf8.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "notes.h"
   9 #include "gpg-interface.h"
  10 #include "mergesort.h"
  11 #include "commit-slab.h"
  12 #include "prio-queue.h"
  13 #include "sha1-lookup.h"
  14
  15 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  16
  17 int save_commit_buffer = 1;
  18
  19 const char *commit_type = "commit";
  20
  21 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  22                                               int quiet)
  23 {
  24         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  25
  26         if (!obj)
  27                 return NULL;
  28         return object_as_type(obj, OBJ_COMMIT, quiet);
  29 }
  30
  31 struct commit *lookup_commit_reference(const unsigned char *sha1)
  32 {
  33         return lookup_commit_reference_gently(sha1, 0);
  34 }
  35
  36 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  37 {
  38         struct commit *c = lookup_commit_reference(sha1);
  39         if (!c)
  40                 die(_("could not parse %s"), ref_name);
  41         if (hashcmp(sha1, c->object.sha1)) {
  42                 warning(_("%s %s is not a commit!"),
  43                         ref_name, sha1_to_hex(sha1));
  44         }
  45         return c;
  46 }
  47
  48 struct commit *lookup_commit(const unsigned char *sha1)
  49 {
  50         struct object *obj = lookup_object(sha1);
  51         if (!obj)
  52                 return create_object(sha1, alloc_commit_node());
  53         return object_as_type(obj, OBJ_COMMIT, 0);
  54 }
  55
  56 struct commit *lookup_commit_reference_by_name(const char *name)
  57 {
  58         unsigned char sha1[20];
  59         struct commit *commit;
  60
  61         if (get_sha1_committish(name, sha1))
  62                 return NULL;
  63         commit = lookup_commit_reference(sha1);
  64         if (parse_commit(commit))
  65                 return NULL;
  66         return commit;
  67 }
  68
  69 static unsigned long parse_commit_date(const char *buf, const char *tail)
  70 {
  71         const char *dateptr;
  72
  73         if (buf + 6 >= tail)
  74                 return 0;
  75         if (memcmp(buf, "author", 6))
  76                 return 0;
  77         while (buf < tail && *buf++ != '\n')
  78                 /* nada */;
  79         if (buf + 9 >= tail)
  80                 return 0;
  81         if (memcmp(buf, "committer", 9))
  82                 return 0;
  83         while (buf < tail && *buf++ != '>')
  84                 /* nada */;
  85         if (buf >= tail)
  86                 return 0;
  87         dateptr = buf;
  88         while (buf < tail && *buf++ != '\n')
  89                 /* nada */;
  90         if (buf >= tail)
  91                 return 0;
  92         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  93         return strtoul(dateptr, NULL, 10);
  94 }
  95
  96 static struct commit_graft **commit_graft;
  97 static int commit_graft_alloc, commit_graft_nr;
  98
  99 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 100 {
 101         struct commit_graft **commit_graft_table = table;
 102         return commit_graft_table[index]->sha1;
 103 }
 104
 105 static int commit_graft_pos(const unsigned char *sha1)
 106 {
 107         return sha1_pos(sha1, commit_graft, commit_graft_nr,
 108                         commit_graft_sha1_access);
 109 }
 110
 111 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 112 {
 113         int pos = commit_graft_pos(graft->sha1);
 114
 115         if (0 <= pos) {
 116                 if (ignore_dups)
 117                         free(graft);
 118                 else {
 119                         free(commit_graft[pos]);
 120                         commit_graft[pos] = graft;
 121                 }
 122                 return 1;
 123         }
 124         pos = -pos - 1;
 125         ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 126         commit_graft_nr++;
 127         if (pos < commit_graft_nr)
 128                 memmove(commit_graft + pos + 1,
 129                         commit_graft + pos,
 130                         (commit_graft_nr - pos - 1) *
 131                         sizeof(*commit_graft));
 132         commit_graft[pos] = graft;
 133         return 0;
 134 }
 135
 136 struct commit_graft *read_graft_line(char *buf, int len)
 137 {
 138         /* The format is just "Commit Parent1 Parent2 ...\n" */
 139         int i;
 140         struct commit_graft *graft = NULL;
 141
 142         while (len && isspace(buf[len-1]))
 143                 buf[--len] = '\0';
 144         if (buf[0] == '#' || buf[0] == '\0')
 145                 return NULL;
 146         if ((len + 1) % 41)
 147                 goto bad_graft_data;
 148         i = (len + 1) / 41 - 1;
 149         graft = xmalloc(sizeof(*graft) + 20 * i);
 150         graft->nr_parent = i;
 151         if (get_sha1_hex(buf, graft->sha1))
 152                 goto bad_graft_data;
 153         for (i = 40; i < len; i += 41) {
 154                 if (buf[i] != ' ')
 155                         goto bad_graft_data;
 156                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 157                         goto bad_graft_data;
 158         }
 159         return graft;
 160
 161 bad_graft_data:
 162         error("bad graft data: %s", buf);
 163         free(graft);
 164         return NULL;
 165 }
 166
 167 static int read_graft_file(const char *graft_file)
 168 {
 169         FILE *fp = fopen(graft_file, "r");
 170         struct strbuf buf = STRBUF_INIT;
 171         if (!fp)
 172                 return -1;
 173         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 174                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 175                 struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 176                 if (!graft)
 177                         continue;
 178                 if (register_commit_graft(graft, 1))
 179                         error("duplicate graft data: %s", buf.buf);
 180         }
 181         fclose(fp);
 182         strbuf_release(&buf);
 183         return 0;
 184 }
 185
 186 static void prepare_commit_graft(void)
 187 {
 188         static int commit_graft_prepared;
 189         char *graft_file;
 190
 191         if (commit_graft_prepared)
 192                 return;
 193         graft_file = get_graft_file();
 194         read_graft_file(graft_file);
 195         /* make sure shallows are read */
 196         is_repository_shallow();
 197         commit_graft_prepared = 1;
 198 }
 199
 200 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 201 {
 202         int pos;
 203         prepare_commit_graft();
 204         pos = commit_graft_pos(sha1);
 205         if (pos < 0)
 206                 return NULL;
 207         return commit_graft[pos];
 208 }
 209
 210 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 211 {
 212         int i, ret;
 213         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 214                 ret = fn(commit_graft[i], cb_data);
 215         return ret;
 216 }
 217
 218 int unregister_shallow(const unsigned char *sha1)
 219 {
 220         int pos = commit_graft_pos(sha1);
 221         if (pos < 0)
 222                 return -1;
 223         if (pos + 1 < commit_graft_nr)
 224                 memmove(commit_graft + pos, commit_graft + pos + 1,
 225                                 sizeof(struct commit_graft *)
 226                                 * (commit_graft_nr - pos - 1));
 227         commit_graft_nr--;
 228         return 0;
 229 }
 230
 231 struct commit_buffer {
 232         void *buffer;
 233         unsigned long size;
 234 };
 235 define_commit_slab(buffer_slab, struct commit_buffer);
 236 static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 237
 238 void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
 239 {
 240         struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 241         v->buffer = buffer;
 242         v->size = size;
 243 }
 244
 245 const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
 246 {
 247         struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 248         if (sizep)
 249                 *sizep = v->size;
 250         return v->buffer;
 251 }
 252
 253 const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 254 {
 255         const void *ret = get_cached_commit_buffer(commit, sizep);
 256         if (!ret) {
 257                 enum object_type type;
 258                 unsigned long size;
 259                 ret = read_sha1_file(commit->object.sha1, &type, &size);
 260                 if (!ret)
 261                         die("cannot read commit object %s",
 262                             sha1_to_hex(commit->object.sha1));
 263                 if (type != OBJ_COMMIT)
 264                         die("expected commit for %s, got %s",
 265                             sha1_to_hex(commit->object.sha1), typename(type));
 266                 if (sizep)
 267                         *sizep = size;
 268         }
 269         return ret;
 270 }
 271
 272 void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 273 {
 274         struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 275         if (v->buffer != buffer)
 276                 free((void *)buffer);
 277 }
 278
 279 void free_commit_buffer(struct commit *commit)
 280 {
 281         struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 282         free(v->buffer);
 283         v->buffer = NULL;
 284         v->size = 0;
 285 }
 286
 287 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 288 {
 289         struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 290         void *ret;
 291
 292         ret = v->buffer;
 293         if (sizep)
 294                 *sizep = v->size;
 295
 296         v->buffer = NULL;
 297         v->size = 0;
 298         return ret;
 299 }
 300
 301 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 302 {
 303         const char *tail = buffer;
 304         const char *bufptr = buffer;
 305         unsigned char parent[20];
 306         struct commit_list **pptr;
 307         struct commit_graft *graft;
 308
 309         if (item->object.parsed)
 310                 return 0;
 311         item->object.parsed = 1;
 312         tail += size;
 313         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 314                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 315         if (get_sha1_hex(bufptr + 5, parent) < 0)
 316                 return error("bad tree pointer in commit %s",
 317                              sha1_to_hex(item->object.sha1));
 318         item->tree = lookup_tree(parent);
 319         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 320         pptr = &item->parents;
 321
 322         graft = lookup_commit_graft(item->object.sha1);
 323         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 324                 struct commit *new_parent;
 325
 326                 if (tail <= bufptr + 48 ||
 327                     get_sha1_hex(bufptr + 7, parent) ||
 328                     bufptr[47] != '\n')
 329                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 330                 bufptr += 48;
 331                 /*
 332                  * The clone is shallow if nr_parent < 0, and we must
 333                  * not traverse its real parents even when we unhide them.
 334                  */
 335                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 336                         continue;
 337                 new_parent = lookup_commit(parent);
 338                 if (new_parent)
 339                         pptr = &commit_list_insert(new_parent, pptr)->next;
 340         }
 341         if (graft) {
 342                 int i;
 343                 struct commit *new_parent;
 344                 for (i = 0; i < graft->nr_parent; i++) {
 345                         new_parent = lookup_commit(graft->parent[i]);
 346                         if (!new_parent)
 347                                 continue;
 348                         pptr = &commit_list_insert(new_parent, pptr)->next;
 349                 }
 350         }
 351         item->date = parse_commit_date(bufptr, tail);
 352
 353         return 0;
 354 }
 355
 356 int parse_commit_gently(struct commit *item, int quiet_on_missing)
 357 {
 358         enum object_type type;
 359         void *buffer;
 360         unsigned long size;
 361         int ret;
 362
 363         if (!item)
 364                 return -1;
 365         if (item->object.parsed)
 366                 return 0;
 367         buffer = read_sha1_file(item->object.sha1, &type, &size);
 368         if (!buffer)
 369                 return quiet_on_missing ? -1 :
 370                         error("Could not read %s",
 371                              sha1_to_hex(item->object.sha1));
 372         if (type != OBJ_COMMIT) {
 373                 free(buffer);
 374                 return error("Object %s not a commit",
 375                              sha1_to_hex(item->object.sha1));
 376         }
 377         ret = parse_commit_buffer(item, buffer, size);
 378         if (save_commit_buffer && !ret) {
 379                 set_commit_buffer(item, buffer, size);
 380                 return 0;
 381         }
 382         free(buffer);
 383         return ret;
 384 }
 385
 386 void parse_commit_or_die(struct commit *item)
 387 {
 388         if (parse_commit(item))
 389                 die("unable to parse commit %s",
 390                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 391 }
 392
 393 int find_commit_subject(const char *commit_buffer, const char **subject)
 394 {
 395         const char *eol;
 396         const char *p = commit_buffer;
 397
 398         while (*p && (*p != '\n' || p[1] != '\n'))
 399                 p++;
 400         if (*p) {
 401                 p += 2;
 402                 for (eol = p; *eol && *eol != '\n'; eol++)
 403                         ; /* do nothing */
 404         } else
 405                 eol = p;
 406
 407         *subject = p;
 408
 409         return eol - p;
 410 }
 411
 412 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 413 {
 414         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 415         new_list->item = item;
 416         new_list->next = *list_p;
 417         *list_p = new_list;
 418         return new_list;
 419 }
 420
 421 unsigned commit_list_count(const struct commit_list *l)
 422 {
 423         unsigned c = 0;
 424         for (; l; l = l->next )
 425                 c++;
 426         return c;
 427 }
 428
 429 struct commit_list *copy_commit_list(struct commit_list *list)
 430 {
 431         struct commit_list *head = NULL;
 432         struct commit_list **pp = &head;
 433         while (list) {
 434                 pp = commit_list_append(list->item, pp);
 435                 list = list->next;
 436         }
 437         return head;
 438 }
 439
 440 void free_commit_list(struct commit_list *list)
 441 {
 442         while (list) {
 443                 struct commit_list *temp = list;
 444                 list = temp->next;
 445                 free(temp);
 446         }
 447 }
 448
 449 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 450 {
 451         struct commit_list **pp = list;
 452         struct commit_list *p;
 453         while ((p = *pp) != NULL) {
 454                 if (p->item->date < item->date) {
 455                         break;
 456                 }
 457                 pp = &p->next;
 458         }
 459         return commit_list_insert(item, pp);
 460 }
 461
 462 static int commit_list_compare_by_date(const void *a, const void *b)
 463 {
 464         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 465         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 466         if (a_date < b_date)
 467                 return 1;
 468         if (a_date > b_date)
 469                 return -1;
 470         return 0;
 471 }
 472
 473 static void *commit_list_get_next(const void *a)
 474 {
 475         return ((const struct commit_list *)a)->next;
 476 }
 477
 478 static void commit_list_set_next(void *a, void *next)
 479 {
 480         ((struct commit_list *)a)->next = next;
 481 }
 482
 483 void commit_list_sort_by_date(struct commit_list **list)
 484 {
 485         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 486                                 commit_list_compare_by_date);
 487 }
 488
 489 struct commit *pop_most_recent_commit(struct commit_list **list,
 490                                       unsigned int mark)
 491 {
 492         struct commit *ret = (*list)->item;
 493         struct commit_list *parents = ret->parents;
 494         struct commit_list *old = *list;
 495
 496         *list = (*list)->next;
 497         free(old);
 498
 499         while (parents) {
 500                 struct commit *commit = parents->item;
 501                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 502                         commit->object.flags |= mark;
 503                         commit_list_insert_by_date(commit, list);
 504                 }
 505                 parents = parents->next;
 506         }
 507         return ret;
 508 }
 509
 510 static void clear_commit_marks_1(struct commit_list **plist,
 511                                  struct commit *commit, unsigned int mark)
 512 {
 513         while (commit) {
 514                 struct commit_list *parents;
 515
 516                 if (!(mark & commit->object.flags))
 517                         return;
 518
 519                 commit->object.flags &= ~mark;
 520
 521                 parents = commit->parents;
 522                 if (!parents)
 523                         return;
 524
 525                 while ((parents = parents->next))
 526                         commit_list_insert(parents->item, plist);
 527
 528                 commit = commit->parents->item;
 529         }
 530 }
 531
 532 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 533 {
 534         struct commit_list *list = NULL;
 535
 536         while (nr--) {
 537                 commit_list_insert(*commit, &list);
 538                 commit++;
 539         }
 540         while (list)
 541                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 542 }
 543
 544 void clear_commit_marks(struct commit *commit, unsigned int mark)
 545 {
 546         clear_commit_marks_many(1, &commit, mark);
 547 }
 548
 549 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 550 {
 551         struct object *object;
 552         struct commit *commit;
 553         unsigned int i;
 554
 555         for (i = 0; i < a->nr; i++) {
 556                 object = a->objects[i].item;
 557                 commit = lookup_commit_reference_gently(object->sha1, 1);
 558                 if (commit)
 559                         clear_commit_marks(commit, mark);
 560         }
 561 }
 562
 563 struct commit *pop_commit(struct commit_list **stack)
 564 {
 565         struct commit_list *top = *stack;
 566         struct commit *item = top ? top->item : NULL;
 567
 568         if (top) {
 569                 *stack = top->next;
 570                 free(top);
 571         }
 572         return item;
 573 }
 574
 575 /*
 576  * Topological sort support
 577  */
 578
 579 /* count number of children that have not been emitted */
 580 define_commit_slab(indegree_slab, int);
 581
 582 /* record author-date for each commit object */
 583 define_commit_slab(author_date_slab, unsigned long);
 584
 585 static void record_author_date(struct author_date_slab *author_date,
 586                                struct commit *commit)
 587 {
 588         const char *buffer = get_commit_buffer(commit, NULL);
 589         struct ident_split ident;
 590         const char *ident_line;
 591         size_t ident_len;
 592         char *date_end;
 593         unsigned long date;
 594
 595         ident_line = find_commit_header(buffer, "author", &ident_len);
 596         if (!ident_line)
 597                 goto fail_exit; /* no author line */
 598         if (split_ident_line(&ident, ident_line, ident_len) ||
 599             !ident.date_begin || !ident.date_end)
 600                 goto fail_exit; /* malformed "author" line */
 601
 602         date = strtoul(ident.date_begin, &date_end, 10);
 603         if (date_end != ident.date_end)
 604                 goto fail_exit; /* malformed date */
 605         *(author_date_slab_at(author_date, commit)) = date;
 606
 607 fail_exit:
 608         unuse_commit_buffer(commit, buffer);
 609 }
 610
 611 static int compare_commits_by_author_date(const void *a_, const void *b_,
 612                                           void *cb_data)
 613 {
 614         const struct commit *a = a_, *b = b_;
 615         struct author_date_slab *author_date = cb_data;
 616         unsigned long a_date = *(author_date_slab_at(author_date, a));
 617         unsigned long b_date = *(author_date_slab_at(author_date, b));
 618
 619         /* newer commits with larger date first */
 620         if (a_date < b_date)
 621                 return 1;
 622         else if (a_date > b_date)
 623                 return -1;
 624         return 0;
 625 }
 626
 627 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 628 {
 629         const struct commit *a = a_, *b = b_;
 630         /* newer commits with larger date first */
 631         if (a->date < b->date)
 632                 return 1;
 633         else if (a->date > b->date)
 634                 return -1;
 635         return 0;
 636 }
 637
 638 /*
 639  * Performs an in-place topological sort on the list supplied.
 640  */
 641 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 642 {
 643         struct commit_list *next, *orig = *list;
 644         struct commit_list **pptr;
 645         struct indegree_slab indegree;
 646         struct prio_queue queue;
 647         struct commit *commit;
 648         struct author_date_slab author_date;
 649
 650         if (!orig)
 651                 return;
 652         *list = NULL;
 653
 654         init_indegree_slab(&indegree);
 655         memset(&queue, '\0', sizeof(queue));
 656
 657         switch (sort_order) {
 658         default: /* REV_SORT_IN_GRAPH_ORDER */
 659                 queue.compare = NULL;
 660                 break;
 661         case REV_SORT_BY_COMMIT_DATE:
 662                 queue.compare = compare_commits_by_commit_date;
 663                 break;
 664         case REV_SORT_BY_AUTHOR_DATE:
 665                 init_author_date_slab(&author_date);
 666                 queue.compare = compare_commits_by_author_date;
 667                 queue.cb_data = &author_date;
 668                 break;
 669         }
 670
 671         /* Mark them and clear the indegree */
 672         for (next = orig; next; next = next->next) {
 673                 struct commit *commit = next->item;
 674                 *(indegree_slab_at(&indegree, commit)) = 1;
 675                 /* also record the author dates, if needed */
 676                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 677                         record_author_date(&author_date, commit);
 678         }
 679
 680         /* update the indegree */
 681         for (next = orig; next; next = next->next) {
 682                 struct commit_list *parents = next->item->parents;
 683                 while (parents) {
 684                         struct commit *parent = parents->item;
 685                         int *pi = indegree_slab_at(&indegree, parent);
 686
 687                         if (*pi)
 688                                 (*pi)++;
 689                         parents = parents->next;
 690                 }
 691         }
 692
 693         /*
 694          * find the tips
 695          *
 696          * tips are nodes not reachable from any other node in the list
 697          *
 698          * the tips serve as a starting set for the work queue.
 699          */
 700         for (next = orig; next; next = next->next) {
 701                 struct commit *commit = next->item;
 702
 703                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 704                         prio_queue_put(&queue, commit);
 705         }
 706
 707         /*
 708          * This is unfortunate; the initial tips need to be shown
 709          * in the order given from the revision traversal machinery.
 710          */
 711         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 712                 prio_queue_reverse(&queue);
 713
 714         /* We no longer need the commit list */
 715         free_commit_list(orig);
 716
 717         pptr = list;
 718         *list = NULL;
 719         while ((commit = prio_queue_get(&queue)) != NULL) {
 720                 struct commit_list *parents;
 721
 722                 for (parents = commit->parents; parents ; parents = parents->next) {
 723                         struct commit *parent = parents->item;
 724                         int *pi = indegree_slab_at(&indegree, parent);
 725
 726                         if (!*pi)
 727                                 continue;
 728
 729                         /*
 730                          * parents are only enqueued for emission
 731                          * when all their children have been emitted thereby
 732                          * guaranteeing topological order.
 733                          */
 734                         if (--(*pi) == 1)
 735                                 prio_queue_put(&queue, parent);
 736                 }
 737                 /*
 738                  * all children of commit have already been
 739                  * emitted. we can emit it now.
 740                  */
 741                 *(indegree_slab_at(&indegree, commit)) = 0;
 742
 743                 pptr = &commit_list_insert(commit, pptr)->next;
 744         }
 745
 746         clear_indegree_slab(&indegree);
 747         clear_prio_queue(&queue);
 748         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 749                 clear_author_date_slab(&author_date);
 750 }
 751
 752 /* merge-base stuff */
 753
 754 /* Remember to update object flag allocation in object.h */
 755 #define PARENT1         (1u<<16)
 756 #define PARENT2         (1u<<17)
 757 #define STALE           (1u<<18)
 758 #define RESULT          (1u<<19)
 759
 760 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 761
 762 static int queue_has_nonstale(struct prio_queue *queue)
 763 {
 764         int i;
 765         for (i = 0; i < queue->nr; i++) {
 766                 struct commit *commit = queue->array[i].data;
 767                 if (!(commit->object.flags & STALE))
 768                         return 1;
 769         }
 770         return 0;
 771 }
 772
 773 /* all input commits in one and twos[] must have been parsed! */
 774 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 775 {
 776         struct prio_queue queue = { compare_commits_by_commit_date };
 777         struct commit_list *result = NULL;
 778         int i;
 779
 780         one->object.flags |= PARENT1;
 781         if (!n) {
 782                 commit_list_append(one, &result);
 783                 return result;
 784         }
 785         prio_queue_put(&queue, one);
 786
 787         for (i = 0; i < n; i++) {
 788                 twos[i]->object.flags |= PARENT2;
 789                 prio_queue_put(&queue, twos[i]);
 790         }
 791
 792         while (queue_has_nonstale(&queue)) {
 793                 struct commit *commit = prio_queue_get(&queue);
 794                 struct commit_list *parents;
 795                 int flags;
 796
 797                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 798                 if (flags == (PARENT1 | PARENT2)) {
 799                         if (!(commit->object.flags & RESULT)) {
 800                                 commit->object.flags |= RESULT;
 801                                 commit_list_insert_by_date(commit, &result);
 802                         }
 803                         /* Mark parents of a found merge stale */
 804                         flags |= STALE;
 805                 }
 806                 parents = commit->parents;
 807                 while (parents) {
 808                         struct commit *p = parents->item;
 809                         parents = parents->next;
 810                         if ((p->object.flags & flags) == flags)
 811                                 continue;
 812                         if (parse_commit(p))
 813                                 return NULL;
 814                         p->object.flags |= flags;
 815                         prio_queue_put(&queue, p);
 816                 }
 817         }
 818
 819         clear_prio_queue(&queue);
 820         return result;
 821 }
 822
 823 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 824 {
 825         struct commit_list *list = NULL;
 826         struct commit_list *result = NULL;
 827         int i;
 828
 829         for (i = 0; i < n; i++) {
 830                 if (one == twos[i])
 831                         /*
 832                          * We do not mark this even with RESULT so we do not
 833                          * have to clean it up.
 834                          */
 835                         return commit_list_insert(one, &result);
 836         }
 837
 838         if (parse_commit(one))
 839                 return NULL;
 840         for (i = 0; i < n; i++) {
 841                 if (parse_commit(twos[i]))
 842                         return NULL;
 843         }
 844
 845         list = paint_down_to_common(one, n, twos);
 846
 847         while (list) {
 848                 struct commit_list *next = list->next;
 849                 if (!(list->item->object.flags & STALE))
 850                         commit_list_insert_by_date(list->item, &result);
 851                 free(list);
 852                 list = next;
 853         }
 854         return result;
 855 }
 856
 857 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 858 {
 859         struct commit_list *i, *j, *k, *ret = NULL;
 860
 861         if (!in)
 862                 return ret;
 863
 864         commit_list_insert(in->item, &ret);
 865
 866         for (i = in->next; i; i = i->next) {
 867                 struct commit_list *new = NULL, *end = NULL;
 868
 869                 for (j = ret; j; j = j->next) {
 870                         struct commit_list *bases;
 871                         bases = get_merge_bases(i->item, j->item, 1);
 872                         if (!new)
 873                                 new = bases;
 874                         else
 875                                 end->next = bases;
 876                         for (k = bases; k; k = k->next)
 877                                 end = k;
 878                 }
 879                 ret = new;
 880         }
 881         return ret;
 882 }
 883
 884 static int remove_redundant(struct commit **array, int cnt)
 885 {
 886         /*
 887          * Some commit in the array may be an ancestor of
 888          * another commit.  Move such commit to the end of
 889          * the array, and return the number of commits that
 890          * are independent from each other.
 891          */
 892         struct commit **work;
 893         unsigned char *redundant;
 894         int *filled_index;
 895         int i, j, filled;
 896
 897         work = xcalloc(cnt, sizeof(*work));
 898         redundant = xcalloc(cnt, 1);
 899         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 900
 901         for (i = 0; i < cnt; i++)
 902                 parse_commit(array[i]);
 903         for (i = 0; i < cnt; i++) {
 904                 struct commit_list *common;
 905
 906                 if (redundant[i])
 907                         continue;
 908                 for (j = filled = 0; j < cnt; j++) {
 909                         if (i == j || redundant[j])
 910                                 continue;
 911                         filled_index[filled] = j;
 912                         work[filled++] = array[j];
 913                 }
 914                 common = paint_down_to_common(array[i], filled, work);
 915                 if (array[i]->object.flags & PARENT2)
 916                         redundant[i] = 1;
 917                 for (j = 0; j < filled; j++)
 918                         if (work[j]->object.flags & PARENT1)
 919                                 redundant[filled_index[j]] = 1;
 920                 clear_commit_marks(array[i], all_flags);
 921                 for (j = 0; j < filled; j++)
 922                         clear_commit_marks(work[j], all_flags);
 923                 free_commit_list(common);
 924         }
 925
 926         /* Now collect the result */
 927         memcpy(work, array, sizeof(*array) * cnt);
 928         for (i = filled = 0; i < cnt; i++)
 929                 if (!redundant[i])
 930                         array[filled++] = work[i];
 931         for (j = filled, i = 0; i < cnt; i++)
 932                 if (redundant[i])
 933                         array[j++] = work[i];
 934         free(work);
 935         free(redundant);
 936         free(filled_index);
 937         return filled;
 938 }
 939
 940 struct commit_list *get_merge_bases_many(struct commit *one,
 941                                          int n,
 942                                          struct commit **twos,
 943                                          int cleanup)
 944 {
 945         struct commit_list *list;
 946         struct commit **rslt;
 947         struct commit_list *result;
 948         int cnt, i;
 949
 950         result = merge_bases_many(one, n, twos);
 951         for (i = 0; i < n; i++) {
 952                 if (one == twos[i])
 953                         return result;
 954         }
 955         if (!result || !result->next) {
 956                 if (cleanup) {
 957                         clear_commit_marks(one, all_flags);
 958                         clear_commit_marks_many(n, twos, all_flags);
 959                 }
 960                 return result;
 961         }
 962
 963         /* There are more than one */
 964         cnt = commit_list_count(result);
 965         rslt = xcalloc(cnt, sizeof(*rslt));
 966         for (list = result, i = 0; list; list = list->next)
 967                 rslt[i++] = list->item;
 968         free_commit_list(result);
 969
 970         clear_commit_marks(one, all_flags);
 971         clear_commit_marks_many(n, twos, all_flags);
 972
 973         cnt = remove_redundant(rslt, cnt);
 974         result = NULL;
 975         for (i = 0; i < cnt; i++)
 976                 commit_list_insert_by_date(rslt[i], &result);
 977         free(rslt);
 978         return result;
 979 }
 980
 981 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 982                                     int cleanup)
 983 {
 984         return get_merge_bases_many(one, 1, &two, cleanup);
 985 }
 986
 987 /*
 988  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 989  */
 990 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 991 {
 992         if (!with_commit)
 993                 return 1;
 994         while (with_commit) {
 995                 struct commit *other;
 996
 997                 other = with_commit->item;
 998                 with_commit = with_commit->next;
 999                 if (in_merge_bases(other, commit))
1000                         return 1;
1001         }
1002         return 0;
1003 }
1004
1005 /*
1006  * Is "commit" an ancestor of one of the "references"?
1007  */
1008 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1009 {
1010         struct commit_list *bases;
1011         int ret = 0, i;
1012
1013         if (parse_commit(commit))
1014                 return ret;
1015         for (i = 0; i < nr_reference; i++)
1016                 if (parse_commit(reference[i]))
1017                         return ret;
1018
1019         bases = paint_down_to_common(commit, nr_reference, reference);
1020         if (commit->object.flags & PARENT2)
1021                 ret = 1;
1022         clear_commit_marks(commit, all_flags);
1023         clear_commit_marks_many(nr_reference, reference, all_flags);
1024         free_commit_list(bases);
1025         return ret;
1026 }
1027
1028 /*
1029  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1030  */
1031 int in_merge_bases(struct commit *commit, struct commit *reference)
1032 {
1033         return in_merge_bases_many(commit, 1, &reference);
1034 }
1035
1036 struct commit_list *reduce_heads(struct commit_list *heads)
1037 {
1038         struct commit_list *p;
1039         struct commit_list *result = NULL, **tail = &result;
1040         struct commit **array;
1041         int num_head, i;
1042
1043         if (!heads)
1044                 return NULL;
1045
1046         /* Uniquify */
1047         for (p = heads; p; p = p->next)
1048                 p->item->object.flags &= ~STALE;
1049         for (p = heads, num_head = 0; p; p = p->next) {
1050                 if (p->item->object.flags & STALE)
1051                         continue;
1052                 p->item->object.flags |= STALE;
1053                 num_head++;
1054         }
1055         array = xcalloc(num_head, sizeof(*array));
1056         for (p = heads, i = 0; p; p = p->next) {
1057                 if (p->item->object.flags & STALE) {
1058                         array[i++] = p->item;
1059                         p->item->object.flags &= ~STALE;
1060                 }
1061         }
1062         num_head = remove_redundant(array, num_head);
1063         for (i = 0; i < num_head; i++)
1064                 tail = &commit_list_insert(array[i], tail)->next;
1065         return result;
1066 }
1067
1068 static const char gpg_sig_header[] = "gpgsig";
1069 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1070
1071 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1072 {
1073         struct strbuf sig = STRBUF_INIT;
1074         int inspos, copypos;
1075
1076         /* find the end of the header */
1077         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1078
1079         if (!keyid || !*keyid)
1080                 keyid = get_signing_key();
1081         if (sign_buffer(buf, &sig, keyid)) {
1082                 strbuf_release(&sig);
1083                 return -1;
1084         }
1085
1086         for (copypos = 0; sig.buf[copypos]; ) {
1087                 const char *bol = sig.buf + copypos;
1088                 const char *eol = strchrnul(bol, '\n');
1089                 int len = (eol - bol) + !!*eol;
1090
1091                 if (!copypos) {
1092                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1093                         inspos += gpg_sig_header_len;
1094                 }
1095                 strbuf_insert(buf, inspos++, " ", 1);
1096                 strbuf_insert(buf, inspos, bol, len);
1097                 inspos += len;
1098                 copypos += len;
1099         }
1100         strbuf_release(&sig);
1101         return 0;
1102 }
1103
1104 int parse_signed_commit(const struct commit *commit,
1105                         struct strbuf *payload, struct strbuf *signature)
1106 {
1107
1108         unsigned long size;
1109         const char *buffer = get_commit_buffer(commit, &size);
1110         int in_signature, saw_signature = -1;
1111         const char *line, *tail;
1112
1113         line = buffer;
1114         tail = buffer + size;
1115         in_signature = 0;
1116         saw_signature = 0;
1117         while (line < tail) {
1118                 const char *sig = NULL;
1119                 const char *next = memchr(line, '\n', tail - line);
1120
1121                 next = next ? next + 1 : tail;
1122                 if (in_signature && line[0] == ' ')
1123                         sig = line + 1;
1124                 else if (starts_with(line, gpg_sig_header) &&
1125                          line[gpg_sig_header_len] == ' ')
1126                         sig = line + gpg_sig_header_len + 1;
1127                 if (sig) {
1128                         strbuf_add(signature, sig, next - sig);
1129                         saw_signature = 1;
1130                         in_signature = 1;
1131                 } else {
1132                         if (*line == '\n')
1133                                 /* dump the whole remainder of the buffer */
1134                                 next = tail;
1135                         strbuf_add(payload, line, next - line);
1136                         in_signature = 0;
1137                 }
1138                 line = next;
1139         }
1140         unuse_commit_buffer(commit, buffer);
1141         return saw_signature;
1142 }
1143
1144 int remove_signature(struct strbuf *buf)
1145 {
1146         const char *line = buf->buf;
1147         const char *tail = buf->buf + buf->len;
1148         int in_signature = 0;
1149         const char *sig_start = NULL;
1150         const char *sig_end = NULL;
1151
1152         while (line < tail) {
1153                 const char *next = memchr(line, '\n', tail - line);
1154                 next = next ? next + 1 : tail;
1155
1156                 if (in_signature && line[0] == ' ')
1157                         sig_end = next;
1158                 else if (starts_with(line, gpg_sig_header) &&
1159                          line[gpg_sig_header_len] == ' ') {
1160                         sig_start = line;
1161                         sig_end = next;
1162                         in_signature = 1;
1163                 } else {
1164                         if (*line == '\n')
1165                                 /* dump the whole remainder of the buffer */
1166                                 next = tail;
1167                         in_signature = 0;
1168                 }
1169                 line = next;
1170         }
1171
1172         if (sig_start)
1173                 strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1174
1175         return sig_start != NULL;
1176 }
1177
1178 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1179 {
1180         struct merge_remote_desc *desc;
1181         struct commit_extra_header *mergetag;
1182         char *buf;
1183         unsigned long size, len;
1184         enum object_type type;
1185
1186         desc = merge_remote_util(parent);
1187         if (!desc || !desc->obj)
1188                 return;
1189         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1190         if (!buf || type != OBJ_TAG)
1191                 goto free_return;
1192         len = parse_signature(buf, size);
1193         if (size == len)
1194                 goto free_return;
1195         /*
1196          * We could verify this signature and either omit the tag when
1197          * it does not validate, but the integrator may not have the
1198          * public key of the signer of the tag he is merging, while a
1199          * later auditor may have it while auditing, so let's not run
1200          * verify-signed-buffer here for now...
1201          *
1202          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1203          *      warn("warning: signed tag unverified.");
1204          */
1205         mergetag = xcalloc(1, sizeof(*mergetag));
1206         mergetag->key = xstrdup("mergetag");
1207         mergetag->value = buf;
1208         mergetag->len = size;
1209
1210         **tail = mergetag;
1211         *tail = &mergetag->next;
1212         return;
1213
1214 free_return:
1215         free(buf);
1216 }
1217
1218 void check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1219 {
1220         struct strbuf payload = STRBUF_INIT;
1221         struct strbuf signature = STRBUF_INIT;
1222         struct strbuf gpg_output = STRBUF_INIT;
1223         struct strbuf gpg_status = STRBUF_INIT;
1224         int status;
1225
1226         sigc->result = 'N';
1227
1228         if (parse_signed_commit(commit, &payload, &signature) <= 0)
1229                 goto out;
1230         status = verify_signed_buffer(payload.buf, payload.len,
1231                                       signature.buf, signature.len,
1232                                       &gpg_output, &gpg_status);
1233         if (status && !gpg_output.len)
1234                 goto out;
1235         sigc->payload = strbuf_detach(&payload, NULL);
1236         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1237         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1238         parse_gpg_output(sigc);
1239
1240  out:
1241         strbuf_release(&gpg_status);
1242         strbuf_release(&gpg_output);
1243         strbuf_release(&payload);
1244         strbuf_release(&signature);
1245 }
1246
1247
1248
1249 void append_merge_tag_headers(struct commit_list *parents,
1250                               struct commit_extra_header ***tail)
1251 {
1252         while (parents) {
1253                 struct commit *parent = parents->item;
1254                 handle_signed_tag(parent, tail);
1255                 parents = parents->next;
1256         }
1257 }
1258
1259 static void add_extra_header(struct strbuf *buffer,
1260                              struct commit_extra_header *extra)
1261 {
1262         strbuf_addstr(buffer, extra->key);
1263         if (extra->len)
1264                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1265         else
1266                 strbuf_addch(buffer, '\n');
1267 }
1268
1269 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1270                                                       const char **exclude)
1271 {
1272         struct commit_extra_header *extra = NULL;
1273         unsigned long size;
1274         const char *buffer = get_commit_buffer(commit, &size);
1275         extra = read_commit_extra_header_lines(buffer, size, exclude);
1276         unuse_commit_buffer(commit, buffer);
1277         return extra;
1278 }
1279
1280 void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1281 {
1282         struct commit_extra_header *extra, *to_free;
1283
1284         to_free = read_commit_extra_headers(commit, NULL);
1285         for (extra = to_free; extra; extra = extra->next) {
1286                 if (strcmp(extra->key, "mergetag"))
1287                         continue; /* not a merge tag */
1288                 fn(commit, extra, data);
1289         }
1290         free_commit_extra_headers(to_free);
1291 }
1292
1293 static inline int standard_header_field(const char *field, size_t len)
1294 {
1295         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1296                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1297                 (len == 6 && !memcmp(field, "author ", 7)) ||
1298                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1299                 (len == 8 && !memcmp(field, "encoding ", 9)));
1300 }
1301
1302 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1303 {
1304         if (!exclude)
1305                 return 0;
1306
1307         while (*exclude) {
1308                 size_t xlen = strlen(*exclude);
1309                 if (len == xlen &&
1310                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1311                         return 1;
1312                 exclude++;
1313         }
1314         return 0;
1315 }
1316
1317 static struct commit_extra_header *read_commit_extra_header_lines(
1318         const char *buffer, size_t size,
1319         const char **exclude)
1320 {
1321         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1322         const char *line, *next, *eof, *eob;
1323         struct strbuf buf = STRBUF_INIT;
1324
1325         for (line = buffer, eob = line + size;
1326              line < eob && *line != '\n';
1327              line = next) {
1328                 next = memchr(line, '\n', eob - line);
1329                 next = next ? next + 1 : eob;
1330                 if (*line == ' ') {
1331                         /* continuation */
1332                         if (it)
1333                                 strbuf_add(&buf, line + 1, next - (line + 1));
1334                         continue;
1335                 }
1336                 if (it)
1337                         it->value = strbuf_detach(&buf, &it->len);
1338                 strbuf_reset(&buf);
1339                 it = NULL;
1340
1341                 eof = strchr(line, ' ');
1342                 if (next <= eof)
1343                         eof = next;
1344
1345                 if (standard_header_field(line, eof - line) ||
1346                     excluded_header_field(line, eof - line, exclude))
1347                         continue;
1348
1349                 it = xcalloc(1, sizeof(*it));
1350                 it->key = xmemdupz(line, eof-line);
1351                 *tail = it;
1352                 tail = &it->next;
1353                 if (eof + 1 < next)
1354                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1355         }
1356         if (it)
1357                 it->value = strbuf_detach(&buf, &it->len);
1358         return extra;
1359 }
1360
1361 void free_commit_extra_headers(struct commit_extra_header *extra)
1362 {
1363         while (extra) {
1364                 struct commit_extra_header *next = extra->next;
1365                 free(extra->key);
1366                 free(extra->value);
1367                 free(extra);
1368                 extra = next;
1369         }
1370 }
1371
1372 int commit_tree(const char *msg, size_t msg_len,
1373                 const unsigned char *tree,
1374                 struct commit_list *parents, unsigned char *ret,
1375                 const char *author, const char *sign_commit)
1376 {
1377         struct commit_extra_header *extra = NULL, **tail = &extra;
1378         int result;
1379
1380         append_merge_tag_headers(parents, &tail);
1381         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1382                                       author, sign_commit, extra);
1383         free_commit_extra_headers(extra);
1384         return result;
1385 }
1386
1387 static int find_invalid_utf8(const char *buf, int len)
1388 {
1389         int offset = 0;
1390         static const unsigned int max_codepoint[] = {
1391                 0x7f, 0x7ff, 0xffff, 0x10ffff
1392         };
1393
1394         while (len) {
1395                 unsigned char c = *buf++;
1396                 int bytes, bad_offset;
1397                 unsigned int codepoint;
1398                 unsigned int min_val, max_val;
1399
1400                 len--;
1401                 offset++;
1402
1403                 /* Simple US-ASCII? No worries. */
1404                 if (c < 0x80)
1405                         continue;
1406
1407                 bad_offset = offset-1;
1408
1409                 /*
1410                  * Count how many more high bits set: that's how
1411                  * many more bytes this sequence should have.
1412                  */
1413                 bytes = 0;
1414                 while (c & 0x40) {
1415                         c <<= 1;
1416                         bytes++;
1417                 }
1418
1419                 /*
1420                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1421                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1422                  */
1423                 if (bytes < 1 || 3 < bytes)
1424                         return bad_offset;
1425
1426                 /* Do we *have* that many bytes? */
1427                 if (len < bytes)
1428                         return bad_offset;
1429
1430                 /*
1431                  * Place the encoded bits at the bottom of the value and compute the
1432                  * valid range.
1433                  */
1434                 codepoint = (c & 0x7f) >> bytes;
1435                 min_val = max_codepoint[bytes-1] + 1;
1436                 max_val = max_codepoint[bytes];
1437
1438                 offset += bytes;
1439                 len -= bytes;
1440
1441                 /* And verify that they are good continuation bytes */
1442                 do {
1443                         codepoint <<= 6;
1444                         codepoint |= *buf & 0x3f;
1445                         if ((*buf++ & 0xc0) != 0x80)
1446                                 return bad_offset;
1447                 } while (--bytes);
1448
1449                 /* Reject codepoints that are out of range for the sequence length. */
1450                 if (codepoint < min_val || codepoint > max_val)
1451                         return bad_offset;
1452                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1453                 if ((codepoint & 0x1ff800) == 0xd800)
1454                         return bad_offset;
1455                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1456                 if ((codepoint & 0xfffe) == 0xfffe)
1457                         return bad_offset;
1458                 /* So are anything in the range U+FDD0..U+FDEF. */
1459                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1460                         return bad_offset;
1461         }
1462         return -1;
1463 }
1464
1465 /*
1466  * This verifies that the buffer is in proper utf8 format.
1467  *
1468  * If it isn't, it assumes any non-utf8 characters are Latin1,
1469  * and does the conversion.
1470  */
1471 static int verify_utf8(struct strbuf *buf)
1472 {
1473         int ok = 1;
1474         long pos = 0;
1475
1476         for (;;) {
1477                 int bad;
1478                 unsigned char c;
1479                 unsigned char replace[2];
1480
1481                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1482                 if (bad < 0)
1483                         return ok;
1484                 pos += bad;
1485                 ok = 0;
1486                 c = buf->buf[pos];
1487                 strbuf_remove(buf, pos, 1);
1488
1489                 /* We know 'c' must be in the range 128-255 */
1490                 replace[0] = 0xc0 + (c >> 6);
1491                 replace[1] = 0x80 + (c & 0x3f);
1492                 strbuf_insert(buf, pos, replace, 2);
1493                 pos += 2;
1494         }
1495 }
1496
1497 static const char commit_utf8_warn[] =
1498 "Warning: commit message did not conform to UTF-8.\n"
1499 "You may want to amend it after fixing the message, or set the config\n"
1500 "variable i18n.commitencoding to the encoding your project uses.\n";
1501
1502 int commit_tree_extended(const char *msg, size_t msg_len,
1503                          const unsigned char *tree,
1504                          struct commit_list *parents, unsigned char *ret,
1505                          const char *author, const char *sign_commit,
1506                          struct commit_extra_header *extra)
1507 {
1508         int result;
1509         int encoding_is_utf8;
1510         struct strbuf buffer;
1511
1512         assert_sha1_type(tree, OBJ_TREE);
1513
1514         if (memchr(msg, '\0', msg_len))
1515                 return error("a NUL byte in commit log message not allowed.");
1516
1517         /* Not having i18n.commitencoding is the same as having utf-8 */
1518         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1519
1520         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1521         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1522
1523         /*
1524          * NOTE! This ordering means that the same exact tree merged with a
1525          * different order of parents will be a _different_ changeset even
1526          * if everything else stays the same.
1527          */
1528         while (parents) {
1529                 struct commit_list *next = parents->next;
1530                 struct commit *parent = parents->item;
1531
1532                 strbuf_addf(&buffer, "parent %s\n",
1533                             sha1_to_hex(parent->object.sha1));
1534                 free(parents);
1535                 parents = next;
1536         }
1537
1538         /* Person/date information */
1539         if (!author)
1540                 author = git_author_info(IDENT_STRICT);
1541         strbuf_addf(&buffer, "author %s\n", author);
1542         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1543         if (!encoding_is_utf8)
1544                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1545
1546         while (extra) {
1547                 add_extra_header(&buffer, extra);
1548                 extra = extra->next;
1549         }
1550         strbuf_addch(&buffer, '\n');
1551
1552         /* And add the comment */
1553         strbuf_add(&buffer, msg, msg_len);
1554
1555         /* And check the encoding */
1556         if (encoding_is_utf8 && !verify_utf8(&buffer))
1557                 fprintf(stderr, commit_utf8_warn);
1558
1559         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1560                 return -1;
1561
1562         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1563         strbuf_release(&buffer);
1564         return result;
1565 }
1566
1567 struct commit *get_merge_parent(const char *name)
1568 {
1569         struct object *obj;
1570         struct commit *commit;
1571         unsigned char sha1[20];
1572         if (get_sha1(name, sha1))
1573                 return NULL;
1574         obj = parse_object(sha1);
1575         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1576         if (commit && !commit->util) {
1577                 struct merge_remote_desc *desc;
1578                 desc = xmalloc(sizeof(*desc));
1579                 desc->obj = obj;
1580                 desc->name = strdup(name);
1581                 commit->util = desc;
1582         }
1583         return commit;
1584 }
1585
1586 /*
1587  * Append a commit to the end of the commit_list.
1588  *
1589  * next starts by pointing to the variable that holds the head of an
1590  * empty commit_list, and is updated to point to the "next" field of
1591  * the last item on the list as new commits are appended.
1592  *
1593  * Usage example:
1594  *
1595  *     struct commit_list *list;
1596  *     struct commit_list **next = &list;
1597  *
1598  *     next = commit_list_append(c1, next);
1599  *     next = commit_list_append(c2, next);
1600  *     assert(commit_list_count(list) == 2);
1601  *     return list;
1602  */
1603 struct commit_list **commit_list_append(struct commit *commit,
1604                                         struct commit_list **next)
1605 {
1606         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1607         new->item = commit;
1608         *next = new;
1609         new->next = NULL;
1610         return &new->next;
1611 }
1612
1613 void print_commit_list(struct commit_list *list,
1614                        const char *format_cur,
1615                        const char *format_last)
1616 {
1617         for ( ; list; list = list->next) {
1618                 const char *format = list->next ? format_cur : format_last;
1619                 printf(format, sha1_to_hex(list->item->object.sha1));
1620         }
1621 }
1622
1623 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1624 {
1625         int key_len = strlen(key);
1626         const char *line = msg;
1627
1628         while (line) {
1629                 const char *eol = strchrnul(line, '\n');
1630
1631                 if (line == eol)
1632                         return NULL;
1633
1634                 if (eol - line > key_len &&
1635                     !strncmp(line, key, key_len) &&
1636                     line[key_len] == ' ') {
1637                         *out_len = eol - line - key_len - 1;
1638                         return line + key_len + 1;
1639                 }
1640                 line = *eol ? eol + 1 : NULL;
1641         }
1642         return NULL;
1643 }