commit.c

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