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(struct commit *item)
 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 error("Could not read %s",
 370                              sha1_to_hex(item->object.sha1));
 371         if (type != OBJ_COMMIT) {
 372                 free(buffer);
 373                 return error("Object %s not a commit",
 374                              sha1_to_hex(item->object.sha1));
 375         }
 376         ret = parse_commit_buffer(item, buffer, size);
 377         if (save_commit_buffer && !ret) {
 378                 set_commit_buffer(item, buffer, size);
 379                 return 0;
 380         }
 381         free(buffer);
 382         return ret;
 383 }
 384
 385 void parse_commit_or_die(struct commit *item)
 386 {
 387         if (parse_commit(item))
 388                 die("unable to parse commit %s",
 389                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 390 }
 391
 392 int find_commit_subject(const char *commit_buffer, const char **subject)
 393 {
 394         const char *eol;
 395         const char *p = commit_buffer;
 396
 397         while (*p && (*p != '\n' || p[1] != '\n'))
 398                 p++;
 399         if (*p) {
 400                 p += 2;
 401                 for (eol = p; *eol && *eol != '\n'; eol++)
 402                         ; /* do nothing */
 403         } else
 404                 eol = p;
 405
 406         *subject = p;
 407
 408         return eol - p;
 409 }
 410
 411 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 412 {
 413         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 414         new_list->item = item;
 415         new_list->next = *list_p;
 416         *list_p = new_list;
 417         return new_list;
 418 }
 419
 420 unsigned commit_list_count(const struct commit_list *l)
 421 {
 422         unsigned c = 0;
 423         for (; l; l = l->next )
 424                 c++;
 425         return c;
 426 }
 427
 428 struct commit_list *copy_commit_list(struct commit_list *list)
 429 {
 430         struct commit_list *head = NULL;
 431         struct commit_list **pp = &head;
 432         while (list) {
 433                 pp = commit_list_append(list->item, pp);
 434                 list = list->next;
 435         }
 436         return head;
 437 }
 438
 439 void free_commit_list(struct commit_list *list)
 440 {
 441         while (list) {
 442                 struct commit_list *temp = list;
 443                 list = temp->next;
 444                 free(temp);
 445         }
 446 }
 447
 448 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 449 {
 450         struct commit_list **pp = list;
 451         struct commit_list *p;
 452         while ((p = *pp) != NULL) {
 453                 if (p->item->date < item->date) {
 454                         break;
 455                 }
 456                 pp = &p->next;
 457         }
 458         return commit_list_insert(item, pp);
 459 }
 460
 461 static int commit_list_compare_by_date(const void *a, const void *b)
 462 {
 463         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 464         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 465         if (a_date < b_date)
 466                 return 1;
 467         if (a_date > b_date)
 468                 return -1;
 469         return 0;
 470 }
 471
 472 static void *commit_list_get_next(const void *a)
 473 {
 474         return ((const struct commit_list *)a)->next;
 475 }
 476
 477 static void commit_list_set_next(void *a, void *next)
 478 {
 479         ((struct commit_list *)a)->next = next;
 480 }
 481
 482 void commit_list_sort_by_date(struct commit_list **list)
 483 {
 484         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 485                                 commit_list_compare_by_date);
 486 }
 487
 488 struct commit *pop_most_recent_commit(struct commit_list **list,
 489                                       unsigned int mark)
 490 {
 491         struct commit *ret = (*list)->item;
 492         struct commit_list *parents = ret->parents;
 493         struct commit_list *old = *list;
 494
 495         *list = (*list)->next;
 496         free(old);
 497
 498         while (parents) {
 499                 struct commit *commit = parents->item;
 500                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 501                         commit->object.flags |= mark;
 502                         commit_list_insert_by_date(commit, list);
 503                 }
 504                 parents = parents->next;
 505         }
 506         return ret;
 507 }
 508
 509 static void clear_commit_marks_1(struct commit_list **plist,
 510                                  struct commit *commit, unsigned int mark)
 511 {
 512         while (commit) {
 513                 struct commit_list *parents;
 514
 515                 if (!(mark & commit->object.flags))
 516                         return;
 517
 518                 commit->object.flags &= ~mark;
 519
 520                 parents = commit->parents;
 521                 if (!parents)
 522                         return;
 523
 524                 while ((parents = parents->next))
 525                         commit_list_insert(parents->item, plist);
 526
 527                 commit = commit->parents->item;
 528         }
 529 }
 530
 531 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 532 {
 533         struct commit_list *list = NULL;
 534
 535         while (nr--) {
 536                 commit_list_insert(*commit, &list);
 537                 commit++;
 538         }
 539         while (list)
 540                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 541 }
 542
 543 void clear_commit_marks(struct commit *commit, unsigned int mark)
 544 {
 545         clear_commit_marks_many(1, &commit, mark);
 546 }
 547
 548 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 549 {
 550         struct object *object;
 551         struct commit *commit;
 552         unsigned int i;
 553
 554         for (i = 0; i < a->nr; i++) {
 555                 object = a->objects[i].item;
 556                 commit = lookup_commit_reference_gently(object->sha1, 1);
 557                 if (commit)
 558                         clear_commit_marks(commit, mark);
 559         }
 560 }
 561
 562 struct commit *pop_commit(struct commit_list **stack)
 563 {
 564         struct commit_list *top = *stack;
 565         struct commit *item = top ? top->item : NULL;
 566
 567         if (top) {
 568                 *stack = top->next;
 569                 free(top);
 570         }
 571         return item;
 572 }
 573
 574 /*
 575  * Topological sort support
 576  */
 577
 578 /* count number of children that have not been emitted */
 579 define_commit_slab(indegree_slab, int);
 580
 581 /* record author-date for each commit object */
 582 define_commit_slab(author_date_slab, unsigned long);
 583
 584 static void record_author_date(struct author_date_slab *author_date,
 585                                struct commit *commit)
 586 {
 587         const char *buffer = get_commit_buffer(commit, NULL);
 588         struct ident_split ident;
 589         const char *ident_line;
 590         size_t ident_len;
 591         char *date_end;
 592         unsigned long date;
 593
 594         ident_line = find_commit_header(buffer, "author", &ident_len);
 595         if (!ident_line)
 596                 goto fail_exit; /* no author line */
 597         if (split_ident_line(&ident, ident_line, ident_len) ||
 598             !ident.date_begin || !ident.date_end)
 599                 goto fail_exit; /* malformed "author" line */
 600
 601         date = strtoul(ident.date_begin, &date_end, 10);
 602         if (date_end != ident.date_end)
 603                 goto fail_exit; /* malformed date */
 604         *(author_date_slab_at(author_date, commit)) = date;
 605
 606 fail_exit:
 607         unuse_commit_buffer(commit, buffer);
 608 }
 609
 610 static int compare_commits_by_author_date(const void *a_, const void *b_,
 611                                           void *cb_data)
 612 {
 613         const struct commit *a = a_, *b = b_;
 614         struct author_date_slab *author_date = cb_data;
 615         unsigned long a_date = *(author_date_slab_at(author_date, a));
 616         unsigned long b_date = *(author_date_slab_at(author_date, b));
 617
 618         /* newer commits with larger date first */
 619         if (a_date < b_date)
 620                 return 1;
 621         else if (a_date > b_date)
 622                 return -1;
 623         return 0;
 624 }
 625
 626 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 627 {
 628         const struct commit *a = a_, *b = b_;
 629         /* newer commits with larger date first */
 630         if (a->date < b->date)
 631                 return 1;
 632         else if (a->date > b->date)
 633                 return -1;
 634         return 0;
 635 }
 636
 637 /*
 638  * Performs an in-place topological sort on the list supplied.
 639  */
 640 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 641 {
 642         struct commit_list *next, *orig = *list;
 643         struct commit_list **pptr;
 644         struct indegree_slab indegree;
 645         struct prio_queue queue;
 646         struct commit *commit;
 647         struct author_date_slab author_date;
 648
 649         if (!orig)
 650                 return;
 651         *list = NULL;
 652
 653         init_indegree_slab(&indegree);
 654         memset(&queue, '\0', sizeof(queue));
 655
 656         switch (sort_order) {
 657         default: /* REV_SORT_IN_GRAPH_ORDER */
 658                 queue.compare = NULL;
 659                 break;
 660         case REV_SORT_BY_COMMIT_DATE:
 661                 queue.compare = compare_commits_by_commit_date;
 662                 break;
 663         case REV_SORT_BY_AUTHOR_DATE:
 664                 init_author_date_slab(&author_date);
 665                 queue.compare = compare_commits_by_author_date;
 666                 queue.cb_data = &author_date;
 667                 break;
 668         }
 669
 670         /* Mark them and clear the indegree */
 671         for (next = orig; next; next = next->next) {
 672                 struct commit *commit = next->item;
 673                 *(indegree_slab_at(&indegree, commit)) = 1;
 674                 /* also record the author dates, if needed */
 675                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 676                         record_author_date(&author_date, commit);
 677         }
 678
 679         /* update the indegree */
 680         for (next = orig; next; next = next->next) {
 681                 struct commit_list *parents = next->item->parents;
 682                 while (parents) {
 683                         struct commit *parent = parents->item;
 684                         int *pi = indegree_slab_at(&indegree, parent);
 685
 686                         if (*pi)
 687                                 (*pi)++;
 688                         parents = parents->next;
 689                 }
 690         }
 691
 692         /*
 693          * find the tips
 694          *
 695          * tips are nodes not reachable from any other node in the list
 696          *
 697          * the tips serve as a starting set for the work queue.
 698          */
 699         for (next = orig; next; next = next->next) {
 700                 struct commit *commit = next->item;
 701
 702                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 703                         prio_queue_put(&queue, commit);
 704         }
 705
 706         /*
 707          * This is unfortunate; the initial tips need to be shown
 708          * in the order given from the revision traversal machinery.
 709          */
 710         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 711                 prio_queue_reverse(&queue);
 712
 713         /* We no longer need the commit list */
 714         free_commit_list(orig);
 715
 716         pptr = list;
 717         *list = NULL;
 718         while ((commit = prio_queue_get(&queue)) != NULL) {
 719                 struct commit_list *parents;
 720
 721                 for (parents = commit->parents; parents ; parents = parents->next) {
 722                         struct commit *parent = parents->item;
 723                         int *pi = indegree_slab_at(&indegree, parent);
 724
 725                         if (!*pi)
 726                                 continue;
 727
 728                         /*
 729                          * parents are only enqueued for emission
 730                          * when all their children have been emitted thereby
 731                          * guaranteeing topological order.
 732                          */
 733                         if (--(*pi) == 1)
 734                                 prio_queue_put(&queue, parent);
 735                 }
 736                 /*
 737                  * all children of commit have already been
 738                  * emitted. we can emit it now.
 739                  */
 740                 *(indegree_slab_at(&indegree, commit)) = 0;
 741
 742                 pptr = &commit_list_insert(commit, pptr)->next;
 743         }
 744
 745         clear_indegree_slab(&indegree);
 746         clear_prio_queue(&queue);
 747         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 748                 clear_author_date_slab(&author_date);
 749 }
 750
 751 /* merge-base stuff */
 752
 753 /* Remember to update object flag allocation in object.h */
 754 #define PARENT1         (1u<<16)
 755 #define PARENT2         (1u<<17)
 756 #define STALE           (1u<<18)
 757 #define RESULT          (1u<<19)
 758
 759 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 760
 761 static int queue_has_nonstale(struct prio_queue *queue)
 762 {
 763         int i;
 764         for (i = 0; i < queue->nr; i++) {
 765                 struct commit *commit = queue->array[i].data;
 766                 if (!(commit->object.flags & STALE))
 767                         return 1;
 768         }
 769         return 0;
 770 }
 771
 772 /* all input commits in one and twos[] must have been parsed! */
 773 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 774 {
 775         struct prio_queue queue = { compare_commits_by_commit_date };
 776         struct commit_list *result = NULL;
 777         int i;
 778
 779         one->object.flags |= PARENT1;
 780         if (!n) {
 781                 commit_list_append(one, &result);
 782                 return result;
 783         }
 784         prio_queue_put(&queue, one);
 785
 786         for (i = 0; i < n; i++) {
 787                 twos[i]->object.flags |= PARENT2;
 788                 prio_queue_put(&queue, twos[i]);
 789         }
 790
 791         while (queue_has_nonstale(&queue)) {
 792                 struct commit *commit = prio_queue_get(&queue);
 793                 struct commit_list *parents;
 794                 int flags;
 795
 796                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 797                 if (flags == (PARENT1 | PARENT2)) {
 798                         if (!(commit->object.flags & RESULT)) {
 799                                 commit->object.flags |= RESULT;
 800                                 commit_list_insert_by_date(commit, &result);
 801                         }
 802                         /* Mark parents of a found merge stale */
 803                         flags |= STALE;
 804                 }
 805                 parents = commit->parents;
 806                 while (parents) {
 807                         struct commit *p = parents->item;
 808                         parents = parents->next;
 809                         if ((p->object.flags & flags) == flags)
 810                                 continue;
 811                         if (parse_commit(p))
 812                                 return NULL;
 813                         p->object.flags |= flags;
 814                         prio_queue_put(&queue, p);
 815                 }
 816         }
 817
 818         clear_prio_queue(&queue);
 819         return result;
 820 }
 821
 822 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 823 {
 824         struct commit_list *list = NULL;
 825         struct commit_list *result = NULL;
 826         int i;
 827
 828         for (i = 0; i < n; i++) {
 829                 if (one == twos[i])
 830                         /*
 831                          * We do not mark this even with RESULT so we do not
 832                          * have to clean it up.
 833                          */
 834                         return commit_list_insert(one, &result);
 835         }
 836
 837         if (parse_commit(one))
 838                 return NULL;
 839         for (i = 0; i < n; i++) {
 840                 if (parse_commit(twos[i]))
 841                         return NULL;
 842         }
 843
 844         list = paint_down_to_common(one, n, twos);
 845
 846         while (list) {
 847                 struct commit_list *next = list->next;
 848                 if (!(list->item->object.flags & STALE))
 849                         commit_list_insert_by_date(list->item, &result);
 850                 free(list);
 851                 list = next;
 852         }
 853         return result;
 854 }
 855
 856 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 857 {
 858         struct commit_list *i, *j, *k, *ret = NULL;
 859
 860         if (!in)
 861                 return ret;
 862
 863         commit_list_insert(in->item, &ret);
 864
 865         for (i = in->next; i; i = i->next) {
 866                 struct commit_list *new = NULL, *end = NULL;
 867
 868                 for (j = ret; j; j = j->next) {
 869                         struct commit_list *bases;
 870                         bases = get_merge_bases(i->item, j->item, 1);
 871                         if (!new)
 872                                 new = bases;
 873                         else
 874                                 end->next = bases;
 875                         for (k = bases; k; k = k->next)
 876                                 end = k;
 877                 }
 878                 ret = new;
 879         }
 880         return ret;
 881 }
 882
 883 static int remove_redundant(struct commit **array, int cnt)
 884 {
 885         /*
 886          * Some commit in the array may be an ancestor of
 887          * another commit.  Move such commit to the end of
 888          * the array, and return the number of commits that
 889          * are independent from each other.
 890          */
 891         struct commit **work;
 892         unsigned char *redundant;
 893         int *filled_index;
 894         int i, j, filled;
 895
 896         work = xcalloc(cnt, sizeof(*work));
 897         redundant = xcalloc(cnt, 1);
 898         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 899
 900         for (i = 0; i < cnt; i++)
 901                 parse_commit(array[i]);
 902         for (i = 0; i < cnt; i++) {
 903                 struct commit_list *common;
 904
 905                 if (redundant[i])
 906                         continue;
 907                 for (j = filled = 0; j < cnt; j++) {
 908                         if (i == j || redundant[j])
 909                                 continue;
 910                         filled_index[filled] = j;
 911                         work[filled++] = array[j];
 912                 }
 913                 common = paint_down_to_common(array[i], filled, work);
 914                 if (array[i]->object.flags & PARENT2)
 915                         redundant[i] = 1;
 916                 for (j = 0; j < filled; j++)
 917                         if (work[j]->object.flags & PARENT1)
 918                                 redundant[filled_index[j]] = 1;
 919                 clear_commit_marks(array[i], all_flags);
 920                 for (j = 0; j < filled; j++)
 921                         clear_commit_marks(work[j], all_flags);
 922                 free_commit_list(common);
 923         }
 924
 925         /* Now collect the result */
 926         memcpy(work, array, sizeof(*array) * cnt);
 927         for (i = filled = 0; i < cnt; i++)
 928                 if (!redundant[i])
 929                         array[filled++] = work[i];
 930         for (j = filled, i = 0; i < cnt; i++)
 931                 if (redundant[i])
 932                         array[j++] = work[i];
 933         free(work);
 934         free(redundant);
 935         free(filled_index);
 936         return filled;
 937 }
 938
 939 struct commit_list *get_merge_bases_many(struct commit *one,
 940                                          int n,
 941                                          struct commit **twos,
 942                                          int cleanup)
 943 {
 944         struct commit_list *list;
 945         struct commit **rslt;
 946         struct commit_list *result;
 947         int cnt, i;
 948
 949         result = merge_bases_many(one, n, twos);
 950         for (i = 0; i < n; i++) {
 951                 if (one == twos[i])
 952                         return result;
 953         }
 954         if (!result || !result->next) {
 955                 if (cleanup) {
 956                         clear_commit_marks(one, all_flags);
 957                         clear_commit_marks_many(n, twos, all_flags);
 958                 }
 959                 return result;
 960         }
 961
 962         /* There are more than one */
 963         cnt = commit_list_count(result);
 964         rslt = xcalloc(cnt, sizeof(*rslt));
 965         for (list = result, i = 0; list; list = list->next)
 966                 rslt[i++] = list->item;
 967         free_commit_list(result);
 968
 969         clear_commit_marks(one, all_flags);
 970         clear_commit_marks_many(n, twos, all_flags);
 971
 972         cnt = remove_redundant(rslt, cnt);
 973         result = NULL;
 974         for (i = 0; i < cnt; i++)
 975                 commit_list_insert_by_date(rslt[i], &result);
 976         free(rslt);
 977         return result;
 978 }
 979
 980 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 981                                     int cleanup)
 982 {
 983         return get_merge_bases_many(one, 1, &two, cleanup);
 984 }
 985
 986 /*
 987  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 988  */
 989 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 990 {
 991         if (!with_commit)
 992                 return 1;
 993         while (with_commit) {
 994                 struct commit *other;
 995
 996                 other = with_commit->item;
 997                 with_commit = with_commit->next;
 998                 if (in_merge_bases(other, commit))
 999                         return 1;
1000         }
1001         return 0;
1002 }
1003
1004 /*
1005  * Is "commit" an ancestor of one of the "references"?
1006  */
1007 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1008 {
1009         struct commit_list *bases;
1010         int ret = 0, i;
1011
1012         if (parse_commit(commit))
1013                 return ret;
1014         for (i = 0; i < nr_reference; i++)
1015                 if (parse_commit(reference[i]))
1016                         return ret;
1017
1018         bases = paint_down_to_common(commit, nr_reference, reference);
1019         if (commit->object.flags & PARENT2)
1020                 ret = 1;
1021         clear_commit_marks(commit, all_flags);
1022         clear_commit_marks_many(nr_reference, reference, all_flags);
1023         free_commit_list(bases);
1024         return ret;
1025 }
1026
1027 /*
1028  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1029  */
1030 int in_merge_bases(struct commit *commit, struct commit *reference)
1031 {
1032         return in_merge_bases_many(commit, 1, &reference);
1033 }
1034
1035 struct commit_list *reduce_heads(struct commit_list *heads)
1036 {
1037         struct commit_list *p;
1038         struct commit_list *result = NULL, **tail = &result;
1039         struct commit **array;
1040         int num_head, i;
1041
1042         if (!heads)
1043                 return NULL;
1044
1045         /* Uniquify */
1046         for (p = heads; p; p = p->next)
1047                 p->item->object.flags &= ~STALE;
1048         for (p = heads, num_head = 0; p; p = p->next) {
1049                 if (p->item->object.flags & STALE)
1050                         continue;
1051                 p->item->object.flags |= STALE;
1052                 num_head++;
1053         }
1054         array = xcalloc(num_head, sizeof(*array));
1055         for (p = heads, i = 0; p; p = p->next) {
1056                 if (p->item->object.flags & STALE) {
1057                         array[i++] = p->item;
1058                         p->item->object.flags &= ~STALE;
1059                 }
1060         }
1061         num_head = remove_redundant(array, num_head);
1062         for (i = 0; i < num_head; i++)
1063                 tail = &commit_list_insert(array[i], tail)->next;
1064         return result;
1065 }
1066
1067 static const char gpg_sig_header[] = "gpgsig";
1068 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1069
1070 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1071 {
1072         struct strbuf sig = STRBUF_INIT;
1073         int inspos, copypos;
1074
1075         /* find the end of the header */
1076         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1077
1078         if (!keyid || !*keyid)
1079                 keyid = get_signing_key();
1080         if (sign_buffer(buf, &sig, keyid)) {
1081                 strbuf_release(&sig);
1082                 return -1;
1083         }
1084
1085         for (copypos = 0; sig.buf[copypos]; ) {
1086                 const char *bol = sig.buf + copypos;
1087                 const char *eol = strchrnul(bol, '\n');
1088                 int len = (eol - bol) + !!*eol;
1089
1090                 if (!copypos) {
1091                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1092                         inspos += gpg_sig_header_len;
1093                 }
1094                 strbuf_insert(buf, inspos++, " ", 1);
1095                 strbuf_insert(buf, inspos, bol, len);
1096                 inspos += len;
1097                 copypos += len;
1098         }
1099         strbuf_release(&sig);
1100         return 0;
1101 }
1102
1103 int parse_signed_commit(const struct commit *commit,
1104                         struct strbuf *payload, struct strbuf *signature)
1105 {
1106
1107         unsigned long size;
1108         const char *buffer = get_commit_buffer(commit, &size);
1109         int in_signature, saw_signature = -1;
1110         const char *line, *tail;
1111
1112         line = buffer;
1113         tail = buffer + size;
1114         in_signature = 0;
1115         saw_signature = 0;
1116         while (line < tail) {
1117                 const char *sig = NULL;
1118                 const char *next = memchr(line, '\n', tail - line);
1119
1120                 next = next ? next + 1 : tail;
1121                 if (in_signature && line[0] == ' ')
1122                         sig = line + 1;
1123                 else if (starts_with(line, gpg_sig_header) &&
1124                          line[gpg_sig_header_len] == ' ')
1125                         sig = line + gpg_sig_header_len + 1;
1126                 if (sig) {
1127                         strbuf_add(signature, sig, next - sig);
1128                         saw_signature = 1;
1129                         in_signature = 1;
1130                 } else {
1131                         if (*line == '\n')
1132                                 /* dump the whole remainder of the buffer */
1133                                 next = tail;
1134                         strbuf_add(payload, line, next - line);
1135                         in_signature = 0;
1136                 }
1137                 line = next;
1138         }
1139         unuse_commit_buffer(commit, buffer);
1140         return saw_signature;
1141 }
1142
1143 int remove_signature(struct strbuf *buf)
1144 {
1145         const char *line = buf->buf;
1146         const char *tail = buf->buf + buf->len;
1147         int in_signature = 0;
1148         const char *sig_start = NULL;
1149         const char *sig_end = NULL;
1150
1151         while (line < tail) {
1152                 const char *next = memchr(line, '\n', tail - line);
1153                 next = next ? next + 1 : tail;
1154
1155                 if (in_signature && line[0] == ' ')
1156                         sig_end = next;
1157                 else if (starts_with(line, gpg_sig_header) &&
1158                          line[gpg_sig_header_len] == ' ') {
1159                         sig_start = line;
1160                         sig_end = next;
1161                         in_signature = 1;
1162                 } else {
1163                         if (*line == '\n')
1164                                 /* dump the whole remainder of the buffer */
1165                                 next = tail;
1166                         in_signature = 0;
1167                 }
1168                 line = next;
1169         }
1170
1171         if (sig_start)
1172                 strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1173
1174         return sig_start != NULL;
1175 }
1176
1177 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1178 {
1179         struct merge_remote_desc *desc;
1180         struct commit_extra_header *mergetag;
1181         char *buf;
1182         unsigned long size, len;
1183         enum object_type type;
1184
1185         desc = merge_remote_util(parent);
1186         if (!desc || !desc->obj)
1187                 return;
1188         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1189         if (!buf || type != OBJ_TAG)
1190                 goto free_return;
1191         len = parse_signature(buf, size);
1192         if (size == len)
1193                 goto free_return;
1194         /*
1195          * We could verify this signature and either omit the tag when
1196          * it does not validate, but the integrator may not have the
1197          * public key of the signer of the tag he is merging, while a
1198          * later auditor may have it while auditing, so let's not run
1199          * verify-signed-buffer here for now...
1200          *
1201          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1202          *      warn("warning: signed tag unverified.");
1203          */
1204         mergetag = xcalloc(1, sizeof(*mergetag));
1205         mergetag->key = xstrdup("mergetag");
1206         mergetag->value = buf;
1207         mergetag->len = size;
1208
1209         **tail = mergetag;
1210         *tail = &mergetag->next;
1211         return;
1212
1213 free_return:
1214         free(buf);
1215 }
1216
1217 static struct {
1218         char result;
1219         const char *check;
1220 } sigcheck_gpg_status[] = {
1221         { 'G', "\n[GNUPG:] GOODSIG " },
1222         { 'B', "\n[GNUPG:] BADSIG " },
1223         { 'U', "\n[GNUPG:] TRUST_NEVER" },
1224         { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1225 };
1226
1227 static void parse_gpg_output(struct signature_check *sigc)
1228 {
1229         const char *buf = sigc->gpg_status;
1230         int i;
1231
1232         /* Iterate over all search strings */
1233         for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1234                 const char *found, *next;
1235
1236                 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
1237                         found = strstr(buf, sigcheck_gpg_status[i].check);
1238                         if (!found)
1239                                 continue;
1240                         found += strlen(sigcheck_gpg_status[i].check);
1241                 }
1242                 sigc->result = sigcheck_gpg_status[i].result;
1243                 /* The trust messages are not followed by key/signer information */
1244                 if (sigc->result != 'U') {
1245                         sigc->key = xmemdupz(found, 16);
1246                         found += 17;
1247                         next = strchrnul(found, '\n');
1248                         sigc->signer = xmemdupz(found, next - found);
1249                 }
1250         }
1251 }
1252
1253 void check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1254 {
1255         struct strbuf payload = STRBUF_INIT;
1256         struct strbuf signature = STRBUF_INIT;
1257         struct strbuf gpg_output = STRBUF_INIT;
1258         struct strbuf gpg_status = STRBUF_INIT;
1259         int status;
1260
1261         sigc->result = 'N';
1262
1263         if (parse_signed_commit(commit, &payload, &signature) <= 0)
1264                 goto out;
1265         status = verify_signed_buffer(payload.buf, payload.len,
1266                                       signature.buf, signature.len,
1267                                       &gpg_output, &gpg_status);
1268         if (status && !gpg_output.len)
1269                 goto out;
1270         sigc->payload = strbuf_detach(&payload, NULL);
1271         sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1272         sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1273         parse_gpg_output(sigc);
1274
1275  out:
1276         strbuf_release(&gpg_status);
1277         strbuf_release(&gpg_output);
1278         strbuf_release(&payload);
1279         strbuf_release(&signature);
1280 }
1281
1282
1283
1284 void append_merge_tag_headers(struct commit_list *parents,
1285                               struct commit_extra_header ***tail)
1286 {
1287         while (parents) {
1288                 struct commit *parent = parents->item;
1289                 handle_signed_tag(parent, tail);
1290                 parents = parents->next;
1291         }
1292 }
1293
1294 static void add_extra_header(struct strbuf *buffer,
1295                              struct commit_extra_header *extra)
1296 {
1297         strbuf_addstr(buffer, extra->key);
1298         if (extra->len)
1299                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1300         else
1301                 strbuf_addch(buffer, '\n');
1302 }
1303
1304 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1305                                                       const char **exclude)
1306 {
1307         struct commit_extra_header *extra = NULL;
1308         unsigned long size;
1309         const char *buffer = get_commit_buffer(commit, &size);
1310         extra = read_commit_extra_header_lines(buffer, size, exclude);
1311         unuse_commit_buffer(commit, buffer);
1312         return extra;
1313 }
1314
1315 void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1316 {
1317         struct commit_extra_header *extra, *to_free;
1318
1319         to_free = read_commit_extra_headers(commit, NULL);
1320         for (extra = to_free; extra; extra = extra->next) {
1321                 if (strcmp(extra->key, "mergetag"))
1322                         continue; /* not a merge tag */
1323                 fn(commit, extra, data);
1324         }
1325         free_commit_extra_headers(to_free);
1326 }
1327
1328 static inline int standard_header_field(const char *field, size_t len)
1329 {
1330         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1331                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1332                 (len == 6 && !memcmp(field, "author ", 7)) ||
1333                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1334                 (len == 8 && !memcmp(field, "encoding ", 9)));
1335 }
1336
1337 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1338 {
1339         if (!exclude)
1340                 return 0;
1341
1342         while (*exclude) {
1343                 size_t xlen = strlen(*exclude);
1344                 if (len == xlen &&
1345                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1346                         return 1;
1347                 exclude++;
1348         }
1349         return 0;
1350 }
1351
1352 static struct commit_extra_header *read_commit_extra_header_lines(
1353         const char *buffer, size_t size,
1354         const char **exclude)
1355 {
1356         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1357         const char *line, *next, *eof, *eob;
1358         struct strbuf buf = STRBUF_INIT;
1359
1360         for (line = buffer, eob = line + size;
1361              line < eob && *line != '\n';
1362              line = next) {
1363                 next = memchr(line, '\n', eob - line);
1364                 next = next ? next + 1 : eob;
1365                 if (*line == ' ') {
1366                         /* continuation */
1367                         if (it)
1368                                 strbuf_add(&buf, line + 1, next - (line + 1));
1369                         continue;
1370                 }
1371                 if (it)
1372                         it->value = strbuf_detach(&buf, &it->len);
1373                 strbuf_reset(&buf);
1374                 it = NULL;
1375
1376                 eof = strchr(line, ' ');
1377                 if (next <= eof)
1378                         eof = next;
1379
1380                 if (standard_header_field(line, eof - line) ||
1381                     excluded_header_field(line, eof - line, exclude))
1382                         continue;
1383
1384                 it = xcalloc(1, sizeof(*it));
1385                 it->key = xmemdupz(line, eof-line);
1386                 *tail = it;
1387                 tail = &it->next;
1388                 if (eof + 1 < next)
1389                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1390         }
1391         if (it)
1392                 it->value = strbuf_detach(&buf, &it->len);
1393         return extra;
1394 }
1395
1396 void free_commit_extra_headers(struct commit_extra_header *extra)
1397 {
1398         while (extra) {
1399                 struct commit_extra_header *next = extra->next;
1400                 free(extra->key);
1401                 free(extra->value);
1402                 free(extra);
1403                 extra = next;
1404         }
1405 }
1406
1407 int commit_tree(const char *msg, size_t msg_len,
1408                 const unsigned char *tree,
1409                 struct commit_list *parents, unsigned char *ret,
1410                 const char *author, const char *sign_commit)
1411 {
1412         struct commit_extra_header *extra = NULL, **tail = &extra;
1413         int result;
1414
1415         append_merge_tag_headers(parents, &tail);
1416         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1417                                       author, sign_commit, extra);
1418         free_commit_extra_headers(extra);
1419         return result;
1420 }
1421
1422 static int find_invalid_utf8(const char *buf, int len)
1423 {
1424         int offset = 0;
1425         static const unsigned int max_codepoint[] = {
1426                 0x7f, 0x7ff, 0xffff, 0x10ffff
1427         };
1428
1429         while (len) {
1430                 unsigned char c = *buf++;
1431                 int bytes, bad_offset;
1432                 unsigned int codepoint;
1433                 unsigned int min_val, max_val;
1434
1435                 len--;
1436                 offset++;
1437
1438                 /* Simple US-ASCII? No worries. */
1439                 if (c < 0x80)
1440                         continue;
1441
1442                 bad_offset = offset-1;
1443
1444                 /*
1445                  * Count how many more high bits set: that's how
1446                  * many more bytes this sequence should have.
1447                  */
1448                 bytes = 0;
1449                 while (c & 0x40) {
1450                         c <<= 1;
1451                         bytes++;
1452                 }
1453
1454                 /*
1455                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1456                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1457                  */
1458                 if (bytes < 1 || 3 < bytes)
1459                         return bad_offset;
1460
1461                 /* Do we *have* that many bytes? */
1462                 if (len < bytes)
1463                         return bad_offset;
1464
1465                 /*
1466                  * Place the encoded bits at the bottom of the value and compute the
1467                  * valid range.
1468                  */
1469                 codepoint = (c & 0x7f) >> bytes;
1470                 min_val = max_codepoint[bytes-1] + 1;
1471                 max_val = max_codepoint[bytes];
1472
1473                 offset += bytes;
1474                 len -= bytes;
1475
1476                 /* And verify that they are good continuation bytes */
1477                 do {
1478                         codepoint <<= 6;
1479                         codepoint |= *buf & 0x3f;
1480                         if ((*buf++ & 0xc0) != 0x80)
1481                                 return bad_offset;
1482                 } while (--bytes);
1483
1484                 /* Reject codepoints that are out of range for the sequence length. */
1485                 if (codepoint < min_val || codepoint > max_val)
1486                         return bad_offset;
1487                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1488                 if ((codepoint & 0x1ff800) == 0xd800)
1489                         return bad_offset;
1490                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1491                 if ((codepoint & 0xfffe) == 0xfffe)
1492                         return bad_offset;
1493                 /* So are anything in the range U+FDD0..U+FDEF. */
1494                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1495                         return bad_offset;
1496         }
1497         return -1;
1498 }
1499
1500 /*
1501  * This verifies that the buffer is in proper utf8 format.
1502  *
1503  * If it isn't, it assumes any non-utf8 characters are Latin1,
1504  * and does the conversion.
1505  */
1506 static int verify_utf8(struct strbuf *buf)
1507 {
1508         int ok = 1;
1509         long pos = 0;
1510
1511         for (;;) {
1512                 int bad;
1513                 unsigned char c;
1514                 unsigned char replace[2];
1515
1516                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1517                 if (bad < 0)
1518                         return ok;
1519                 pos += bad;
1520                 ok = 0;
1521                 c = buf->buf[pos];
1522                 strbuf_remove(buf, pos, 1);
1523
1524                 /* We know 'c' must be in the range 128-255 */
1525                 replace[0] = 0xc0 + (c >> 6);
1526                 replace[1] = 0x80 + (c & 0x3f);
1527                 strbuf_insert(buf, pos, replace, 2);
1528                 pos += 2;
1529         }
1530 }
1531
1532 static const char commit_utf8_warn[] =
1533 "Warning: commit message did not conform to UTF-8.\n"
1534 "You may want to amend it after fixing the message, or set the config\n"
1535 "variable i18n.commitencoding to the encoding your project uses.\n";
1536
1537 int commit_tree_extended(const char *msg, size_t msg_len,
1538                          const unsigned char *tree,
1539                          struct commit_list *parents, unsigned char *ret,
1540                          const char *author, const char *sign_commit,
1541                          struct commit_extra_header *extra)
1542 {
1543         int result;
1544         int encoding_is_utf8;
1545         struct strbuf buffer;
1546
1547         assert_sha1_type(tree, OBJ_TREE);
1548
1549         if (memchr(msg, '\0', msg_len))
1550                 return error("a NUL byte in commit log message not allowed.");
1551
1552         /* Not having i18n.commitencoding is the same as having utf-8 */
1553         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1554
1555         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1556         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1557
1558         /*
1559          * NOTE! This ordering means that the same exact tree merged with a
1560          * different order of parents will be a _different_ changeset even
1561          * if everything else stays the same.
1562          */
1563         while (parents) {
1564                 struct commit_list *next = parents->next;
1565                 struct commit *parent = parents->item;
1566
1567                 strbuf_addf(&buffer, "parent %s\n",
1568                             sha1_to_hex(parent->object.sha1));
1569                 free(parents);
1570                 parents = next;
1571         }
1572
1573         /* Person/date information */
1574         if (!author)
1575                 author = git_author_info(IDENT_STRICT);
1576         strbuf_addf(&buffer, "author %s\n", author);
1577         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1578         if (!encoding_is_utf8)
1579                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1580
1581         while (extra) {
1582                 add_extra_header(&buffer, extra);
1583                 extra = extra->next;
1584         }
1585         strbuf_addch(&buffer, '\n');
1586
1587         /* And add the comment */
1588         strbuf_add(&buffer, msg, msg_len);
1589
1590         /* And check the encoding */
1591         if (encoding_is_utf8 && !verify_utf8(&buffer))
1592                 fprintf(stderr, commit_utf8_warn);
1593
1594         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1595                 return -1;
1596
1597         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1598         strbuf_release(&buffer);
1599         return result;
1600 }
1601
1602 struct commit *get_merge_parent(const char *name)
1603 {
1604         struct object *obj;
1605         struct commit *commit;
1606         unsigned char sha1[20];
1607         if (get_sha1(name, sha1))
1608                 return NULL;
1609         obj = parse_object(sha1);
1610         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1611         if (commit && !commit->util) {
1612                 struct merge_remote_desc *desc;
1613                 desc = xmalloc(sizeof(*desc));
1614                 desc->obj = obj;
1615                 desc->name = strdup(name);
1616                 commit->util = desc;
1617         }
1618         return commit;
1619 }
1620
1621 /*
1622  * Append a commit to the end of the commit_list.
1623  *
1624  * next starts by pointing to the variable that holds the head of an
1625  * empty commit_list, and is updated to point to the "next" field of
1626  * the last item on the list as new commits are appended.
1627  *
1628  * Usage example:
1629  *
1630  *     struct commit_list *list;
1631  *     struct commit_list **next = &list;
1632  *
1633  *     next = commit_list_append(c1, next);
1634  *     next = commit_list_append(c2, next);
1635  *     assert(commit_list_count(list) == 2);
1636  *     return list;
1637  */
1638 struct commit_list **commit_list_append(struct commit *commit,
1639                                         struct commit_list **next)
1640 {
1641         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1642         new->item = commit;
1643         *next = new;
1644         new->next = NULL;
1645         return &new->next;
1646 }
1647
1648 void print_commit_list(struct commit_list *list,
1649                        const char *format_cur,
1650                        const char *format_last)
1651 {
1652         for ( ; list; list = list->next) {
1653                 const char *format = list->next ? format_cur : format_last;
1654                 printf(format, sha1_to_hex(list->item->object.sha1));
1655         }
1656 }
1657
1658 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1659 {
1660         int key_len = strlen(key);
1661         const char *line = msg;
1662
1663         while (line) {
1664                 const char *eol = strchrnul(line, '\n');
1665
1666                 if (line == eol)
1667                         return NULL;
1668
1669                 if (eol - line > key_len &&
1670                     !strncmp(line, key, key_len) &&
1671                     line[key_len] == ' ') {
1672                         *out_len = eol - line - key_len - 1;
1673                         return line + key_len + 1;
1674                 }
1675                 line = *eol ? eol + 1 : NULL;
1676         }
1677         return NULL;
1678 }