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 #include "run-command.h"
  23
  24 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  25
  26 int save_commit_buffer = 1;
  27
  28 const char *commit_type = "commit";
  29
  30 struct commit *lookup_commit_reference_gently(struct repository *r,
  31                 const struct object_id *oid, int quiet)
  32 {
  33         struct object *obj = deref_tag(r,
  34                                        parse_object(r, oid),
  35                                        NULL, 0);
  36
  37         if (!obj)
  38                 return NULL;
  39         return object_as_type(r, obj, OBJ_COMMIT, quiet);
  40 }
  41
  42 struct commit *lookup_commit_reference(struct repository *r, const struct object_id *oid)
  43 {
  44         return lookup_commit_reference_gently(r, oid, 0);
  45 }
  46
  47 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
  48 {
  49         struct commit *c = lookup_commit_reference(the_repository, oid);
  50         if (!c)
  51                 die(_("could not parse %s"), ref_name);
  52         if (!oideq(oid, &c->object.oid)) {
  53                 warning(_("%s %s is not a commit!"),
  54                         ref_name, oid_to_hex(oid));
  55         }
  56         return c;
  57 }
  58
  59 struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
  60 {
  61         struct object *obj = lookup_object(r, oid);
  62         if (!obj)
  63                 return create_object(r, oid, 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 static inline void set_commit_tree(struct commit *c, struct tree *t)
 344 {
 345         c->maybe_tree = t;
 346 }
 347
 348 struct tree *repo_get_commit_tree(struct repository *r,
 349                                   const struct commit *commit)
 350 {
 351         if (commit->maybe_tree || !commit->object.parsed)
 352                 return commit->maybe_tree;
 353
 354         if (commit->graph_pos != COMMIT_NOT_FROM_GRAPH)
 355                 return get_commit_tree_in_graph(r, commit);
 356
 357         return NULL;
 358 }
 359
 360 struct object_id *get_commit_tree_oid(const struct commit *commit)
 361 {
 362         struct tree *tree = get_commit_tree(commit);
 363         return tree ? &tree->object.oid : NULL;
 364 }
 365
 366 void release_commit_memory(struct parsed_object_pool *pool, struct commit *c)
 367 {
 368         set_commit_tree(c, NULL);
 369         free_commit_buffer(pool, c);
 370         c->index = 0;
 371         free_commit_list(c->parents);
 372
 373         c->object.parsed = 0;
 374 }
 375
 376 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 377 {
 378         struct commit_buffer *v = buffer_slab_peek(
 379                 the_repository->parsed_objects->buffer_slab, commit);
 380         void *ret;
 381
 382         if (!v) {
 383                 if (sizep)
 384                         *sizep = 0;
 385                 return NULL;
 386         }
 387         ret = v->buffer;
 388         if (sizep)
 389                 *sizep = v->size;
 390
 391         v->buffer = NULL;
 392         v->size = 0;
 393         return ret;
 394 }
 395
 396 int parse_commit_buffer(struct repository *r, struct commit *item, const void *buffer, unsigned long size, int check_graph)
 397 {
 398         const char *tail = buffer;
 399         const char *bufptr = buffer;
 400         struct object_id parent;
 401         struct commit_list **pptr;
 402         struct commit_graft *graft;
 403         const int tree_entry_len = the_hash_algo->hexsz + 5;
 404         const int parent_entry_len = the_hash_algo->hexsz + 7;
 405
 406         if (item->object.parsed)
 407                 return 0;
 408         item->object.parsed = 1;
 409         tail += size;
 410         if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 411                         bufptr[tree_entry_len] != '\n')
 412                 return error("bogus commit object %s", oid_to_hex(&item->object.oid));
 413         if (get_oid_hex(bufptr + 5, &parent) < 0)
 414                 return error("bad tree pointer in commit %s",
 415                              oid_to_hex(&item->object.oid));
 416         set_commit_tree(item, lookup_tree(r, &parent));
 417         bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 418         pptr = &item->parents;
 419
 420         graft = lookup_commit_graft(r, &item->object.oid);
 421         while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 422                 struct commit *new_parent;
 423
 424                 if (tail <= bufptr + parent_entry_len + 1 ||
 425                     get_oid_hex(bufptr + 7, &parent) ||
 426                     bufptr[parent_entry_len] != '\n')
 427                         return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
 428                 bufptr += parent_entry_len + 1;
 429                 /*
 430                  * The clone is shallow if nr_parent < 0, and we must
 431                  * not traverse its real parents even when we unhide them.
 432                  */
 433                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 434                         continue;
 435                 new_parent = lookup_commit(r, &parent);
 436                 if (new_parent)
 437                         pptr = &commit_list_insert(new_parent, pptr)->next;
 438         }
 439         if (graft) {
 440                 int i;
 441                 struct commit *new_parent;
 442                 for (i = 0; i < graft->nr_parent; i++) {
 443                         new_parent = lookup_commit(r,
 444                                                    &graft->parent[i]);
 445                         if (!new_parent)
 446                                 continue;
 447                         pptr = &commit_list_insert(new_parent, pptr)->next;
 448                 }
 449         }
 450         item->date = parse_commit_date(bufptr, tail);
 451
 452         if (check_graph)
 453                 load_commit_graph_info(r, item);
 454
 455         return 0;
 456 }
 457
 458 int repo_parse_commit_internal(struct repository *r,
 459                                struct commit *item,
 460                                int quiet_on_missing,
 461                                int use_commit_graph)
 462 {
 463         enum object_type type;
 464         void *buffer;
 465         unsigned long size;
 466         int ret;
 467
 468         if (!item)
 469                 return -1;
 470         if (item->object.parsed)
 471                 return 0;
 472         if (use_commit_graph && parse_commit_in_graph(r, item))
 473                 return 0;
 474         buffer = repo_read_object_file(r, &item->object.oid, &type, &size);
 475         if (!buffer)
 476                 return quiet_on_missing ? -1 :
 477                         error("Could not read %s",
 478                              oid_to_hex(&item->object.oid));
 479         if (type != OBJ_COMMIT) {
 480                 free(buffer);
 481                 return error("Object %s not a commit",
 482                              oid_to_hex(&item->object.oid));
 483         }
 484
 485         ret = parse_commit_buffer(r, item, buffer, size, 0);
 486         if (save_commit_buffer && !ret) {
 487                 set_commit_buffer(r, item, buffer, size);
 488                 return 0;
 489         }
 490         free(buffer);
 491         return ret;
 492 }
 493
 494 int repo_parse_commit_gently(struct repository *r,
 495                              struct commit *item, int quiet_on_missing)
 496 {
 497         return repo_parse_commit_internal(r, item, quiet_on_missing, 1);
 498 }
 499
 500 void parse_commit_or_die(struct commit *item)
 501 {
 502         if (parse_commit(item))
 503                 die("unable to parse commit %s",
 504                     item ? oid_to_hex(&item->object.oid) : "(null)");
 505 }
 506
 507 int find_commit_subject(const char *commit_buffer, const char **subject)
 508 {
 509         const char *eol;
 510         const char *p = commit_buffer;
 511
 512         while (*p && (*p != '\n' || p[1] != '\n'))
 513                 p++;
 514         if (*p) {
 515                 p = skip_blank_lines(p + 2);
 516                 eol = strchrnul(p, '\n');
 517         } else
 518                 eol = p;
 519
 520         *subject = p;
 521
 522         return eol - p;
 523 }
 524
 525 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 526 {
 527         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 528         new_list->item = item;
 529         new_list->next = *list_p;
 530         *list_p = new_list;
 531         return new_list;
 532 }
 533
 534 unsigned commit_list_count(const struct commit_list *l)
 535 {
 536         unsigned c = 0;
 537         for (; l; l = l->next )
 538                 c++;
 539         return c;
 540 }
 541
 542 struct commit_list *copy_commit_list(struct commit_list *list)
 543 {
 544         struct commit_list *head = NULL;
 545         struct commit_list **pp = &head;
 546         while (list) {
 547                 pp = commit_list_append(list->item, pp);
 548                 list = list->next;
 549         }
 550         return head;
 551 }
 552
 553 void free_commit_list(struct commit_list *list)
 554 {
 555         while (list)
 556                 pop_commit(&list);
 557 }
 558
 559 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 560 {
 561         struct commit_list **pp = list;
 562         struct commit_list *p;
 563         while ((p = *pp) != NULL) {
 564                 if (p->item->date < item->date) {
 565                         break;
 566                 }
 567                 pp = &p->next;
 568         }
 569         return commit_list_insert(item, pp);
 570 }
 571
 572 static int commit_list_compare_by_date(const void *a, const void *b)
 573 {
 574         timestamp_t a_date = ((const struct commit_list *)a)->item->date;
 575         timestamp_t b_date = ((const struct commit_list *)b)->item->date;
 576         if (a_date < b_date)
 577                 return 1;
 578         if (a_date > b_date)
 579                 return -1;
 580         return 0;
 581 }
 582
 583 static void *commit_list_get_next(const void *a)
 584 {
 585         return ((const struct commit_list *)a)->next;
 586 }
 587
 588 static void commit_list_set_next(void *a, void *next)
 589 {
 590         ((struct commit_list *)a)->next = next;
 591 }
 592
 593 void commit_list_sort_by_date(struct commit_list **list)
 594 {
 595         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 596                                 commit_list_compare_by_date);
 597 }
 598
 599 struct commit *pop_most_recent_commit(struct commit_list **list,
 600                                       unsigned int mark)
 601 {
 602         struct commit *ret = pop_commit(list);
 603         struct commit_list *parents = ret->parents;
 604
 605         while (parents) {
 606                 struct commit *commit = parents->item;
 607                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 608                         commit->object.flags |= mark;
 609                         commit_list_insert_by_date(commit, list);
 610                 }
 611                 parents = parents->next;
 612         }
 613         return ret;
 614 }
 615
 616 static void clear_commit_marks_1(struct commit_list **plist,
 617                                  struct commit *commit, unsigned int mark)
 618 {
 619         while (commit) {
 620                 struct commit_list *parents;
 621
 622                 if (!(mark & commit->object.flags))
 623                         return;
 624
 625                 commit->object.flags &= ~mark;
 626
 627                 parents = commit->parents;
 628                 if (!parents)
 629                         return;
 630
 631                 while ((parents = parents->next))
 632                         commit_list_insert(parents->item, plist);
 633
 634                 commit = commit->parents->item;
 635         }
 636 }
 637
 638 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 639 {
 640         struct commit_list *list = NULL;
 641
 642         while (nr--) {
 643                 clear_commit_marks_1(&list, *commit, mark);
 644                 commit++;
 645         }
 646         while (list)
 647                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 648 }
 649
 650 void clear_commit_marks(struct commit *commit, unsigned int mark)
 651 {
 652         clear_commit_marks_many(1, &commit, mark);
 653 }
 654
 655 struct commit *pop_commit(struct commit_list **stack)
 656 {
 657         struct commit_list *top = *stack;
 658         struct commit *item = top ? top->item : NULL;
 659
 660         if (top) {
 661                 *stack = top->next;
 662                 free(top);
 663         }
 664         return item;
 665 }
 666
 667 /*
 668  * Topological sort support
 669  */
 670
 671 /* count number of children that have not been emitted */
 672 define_commit_slab(indegree_slab, int);
 673
 674 define_commit_slab(author_date_slab, timestamp_t);
 675
 676 void record_author_date(struct author_date_slab *author_date,
 677                         struct commit *commit)
 678 {
 679         const char *buffer = get_commit_buffer(commit, NULL);
 680         struct ident_split ident;
 681         const char *ident_line;
 682         size_t ident_len;
 683         char *date_end;
 684         timestamp_t date;
 685
 686         ident_line = find_commit_header(buffer, "author", &ident_len);
 687         if (!ident_line)
 688                 goto fail_exit; /* no author line */
 689         if (split_ident_line(&ident, ident_line, ident_len) ||
 690             !ident.date_begin || !ident.date_end)
 691                 goto fail_exit; /* malformed "author" line */
 692
 693         date = parse_timestamp(ident.date_begin, &date_end, 10);
 694         if (date_end != ident.date_end)
 695                 goto fail_exit; /* malformed date */
 696         *(author_date_slab_at(author_date, commit)) = date;
 697
 698 fail_exit:
 699         unuse_commit_buffer(commit, buffer);
 700 }
 701
 702 int compare_commits_by_author_date(const void *a_, const void *b_,
 703                                    void *cb_data)
 704 {
 705         const struct commit *a = a_, *b = b_;
 706         struct author_date_slab *author_date = cb_data;
 707         timestamp_t a_date = *(author_date_slab_at(author_date, a));
 708         timestamp_t b_date = *(author_date_slab_at(author_date, b));
 709
 710         /* newer commits with larger date first */
 711         if (a_date < b_date)
 712                 return 1;
 713         else if (a_date > b_date)
 714                 return -1;
 715         return 0;
 716 }
 717
 718 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
 719 {
 720         const struct commit *a = a_, *b = b_;
 721
 722         /* newer commits first */
 723         if (a->generation < b->generation)
 724                 return 1;
 725         else if (a->generation > b->generation)
 726                 return -1;
 727
 728         /* use date as a heuristic when generations are equal */
 729         if (a->date < b->date)
 730                 return 1;
 731         else if (a->date > b->date)
 732                 return -1;
 733         return 0;
 734 }
 735
 736 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 737 {
 738         const struct commit *a = a_, *b = b_;
 739         /* newer commits with larger date first */
 740         if (a->date < b->date)
 741                 return 1;
 742         else if (a->date > b->date)
 743                 return -1;
 744         return 0;
 745 }
 746
 747 /*
 748  * Performs an in-place topological sort on the list supplied.
 749  */
 750 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 751 {
 752         struct commit_list *next, *orig = *list;
 753         struct commit_list **pptr;
 754         struct indegree_slab indegree;
 755         struct prio_queue queue;
 756         struct commit *commit;
 757         struct author_date_slab author_date;
 758
 759         if (!orig)
 760                 return;
 761         *list = NULL;
 762
 763         init_indegree_slab(&indegree);
 764         memset(&queue, '\0', sizeof(queue));
 765
 766         switch (sort_order) {
 767         default: /* REV_SORT_IN_GRAPH_ORDER */
 768                 queue.compare = NULL;
 769                 break;
 770         case REV_SORT_BY_COMMIT_DATE:
 771                 queue.compare = compare_commits_by_commit_date;
 772                 break;
 773         case REV_SORT_BY_AUTHOR_DATE:
 774                 init_author_date_slab(&author_date);
 775                 queue.compare = compare_commits_by_author_date;
 776                 queue.cb_data = &author_date;
 777                 break;
 778         }
 779
 780         /* Mark them and clear the indegree */
 781         for (next = orig; next; next = next->next) {
 782                 struct commit *commit = next->item;
 783                 *(indegree_slab_at(&indegree, commit)) = 1;
 784                 /* also record the author dates, if needed */
 785                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 786                         record_author_date(&author_date, commit);
 787         }
 788
 789         /* update the indegree */
 790         for (next = orig; next; next = next->next) {
 791                 struct commit_list *parents = next->item->parents;
 792                 while (parents) {
 793                         struct commit *parent = parents->item;
 794                         int *pi = indegree_slab_at(&indegree, parent);
 795
 796                         if (*pi)
 797                                 (*pi)++;
 798                         parents = parents->next;
 799                 }
 800         }
 801
 802         /*
 803          * find the tips
 804          *
 805          * tips are nodes not reachable from any other node in the list
 806          *
 807          * the tips serve as a starting set for the work queue.
 808          */
 809         for (next = orig; next; next = next->next) {
 810                 struct commit *commit = next->item;
 811
 812                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 813                         prio_queue_put(&queue, commit);
 814         }
 815
 816         /*
 817          * This is unfortunate; the initial tips need to be shown
 818          * in the order given from the revision traversal machinery.
 819          */
 820         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 821                 prio_queue_reverse(&queue);
 822
 823         /* We no longer need the commit list */
 824         free_commit_list(orig);
 825
 826         pptr = list;
 827         *list = NULL;
 828         while ((commit = prio_queue_get(&queue)) != NULL) {
 829                 struct commit_list *parents;
 830
 831                 for (parents = commit->parents; parents ; parents = parents->next) {
 832                         struct commit *parent = parents->item;
 833                         int *pi = indegree_slab_at(&indegree, parent);
 834
 835                         if (!*pi)
 836                                 continue;
 837
 838                         /*
 839                          * parents are only enqueued for emission
 840                          * when all their children have been emitted thereby
 841                          * guaranteeing topological order.
 842                          */
 843                         if (--(*pi) == 1)
 844                                 prio_queue_put(&queue, parent);
 845                 }
 846                 /*
 847                  * all children of commit have already been
 848                  * emitted. we can emit it now.
 849                  */
 850                 *(indegree_slab_at(&indegree, commit)) = 0;
 851
 852                 pptr = &commit_list_insert(commit, pptr)->next;
 853         }
 854
 855         clear_indegree_slab(&indegree);
 856         clear_prio_queue(&queue);
 857         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 858                 clear_author_date_slab(&author_date);
 859 }
 860
 861 struct rev_collect {
 862         struct commit **commit;
 863         int nr;
 864         int alloc;
 865         unsigned int initial : 1;
 866 };
 867
 868 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 869 {
 870         struct commit *commit;
 871
 872         if (is_null_oid(oid))
 873                 return;
 874
 875         commit = lookup_commit(the_repository, oid);
 876         if (!commit ||
 877             (commit->object.flags & TMP_MARK) ||
 878             parse_commit(commit))
 879                 return;
 880
 881         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
 882         revs->commit[revs->nr++] = commit;
 883         commit->object.flags |= TMP_MARK;
 884 }
 885
 886 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 887                                   const char *ident, timestamp_t timestamp,
 888                                   int tz, const char *message, void *cbdata)
 889 {
 890         struct rev_collect *revs = cbdata;
 891
 892         if (revs->initial) {
 893                 revs->initial = 0;
 894                 add_one_commit(ooid, revs);
 895         }
 896         add_one_commit(noid, revs);
 897         return 0;
 898 }
 899
 900 struct commit *get_fork_point(const char *refname, struct commit *commit)
 901 {
 902         struct object_id oid;
 903         struct rev_collect revs;
 904         struct commit_list *bases;
 905         int i;
 906         struct commit *ret = NULL;
 907
 908         memset(&revs, 0, sizeof(revs));
 909         revs.initial = 1;
 910         for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 911
 912         if (!revs.nr && !get_oid(refname, &oid))
 913                 add_one_commit(&oid, &revs);
 914
 915         for (i = 0; i < revs.nr; i++)
 916                 revs.commit[i]->object.flags &= ~TMP_MARK;
 917
 918         bases = get_merge_bases_many(commit, revs.nr, revs.commit);
 919
 920         /*
 921          * There should be one and only one merge base, when we found
 922          * a common ancestor among reflog entries.
 923          */
 924         if (!bases || bases->next)
 925                 goto cleanup_return;
 926
 927         /* And the found one must be one of the reflog entries */
 928         for (i = 0; i < revs.nr; i++)
 929                 if (&bases->item->object == &revs.commit[i]->object)
 930                         break; /* found */
 931         if (revs.nr <= i)
 932                 goto cleanup_return;
 933
 934         ret = bases->item;
 935
 936 cleanup_return:
 937         free_commit_list(bases);
 938         return ret;
 939 }
 940
 941 static const char gpg_sig_header[] = "gpgsig";
 942 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 943
 944 static int do_sign_commit(struct strbuf *buf, const char *keyid)
 945 {
 946         struct strbuf sig = STRBUF_INIT;
 947         int inspos, copypos;
 948         const char *eoh;
 949
 950         /* find the end of the header */
 951         eoh = strstr(buf->buf, "\n\n");
 952         if (!eoh)
 953                 inspos = buf->len;
 954         else
 955                 inspos = eoh - buf->buf + 1;
 956
 957         if (!keyid || !*keyid)
 958                 keyid = get_signing_key();
 959         if (sign_buffer(buf, &sig, keyid)) {
 960                 strbuf_release(&sig);
 961                 return -1;
 962         }
 963
 964         for (copypos = 0; sig.buf[copypos]; ) {
 965                 const char *bol = sig.buf + copypos;
 966                 const char *eol = strchrnul(bol, '\n');
 967                 int len = (eol - bol) + !!*eol;
 968
 969                 if (!copypos) {
 970                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 971                         inspos += gpg_sig_header_len;
 972                 }
 973                 strbuf_insert(buf, inspos++, " ", 1);
 974                 strbuf_insert(buf, inspos, bol, len);
 975                 inspos += len;
 976                 copypos += len;
 977         }
 978         strbuf_release(&sig);
 979         return 0;
 980 }
 981
 982 int parse_signed_commit(const struct commit *commit,
 983                         struct strbuf *payload, struct strbuf *signature)
 984 {
 985
 986         unsigned long size;
 987         const char *buffer = get_commit_buffer(commit, &size);
 988         int in_signature, saw_signature = -1;
 989         const char *line, *tail;
 990
 991         line = buffer;
 992         tail = buffer + size;
 993         in_signature = 0;
 994         saw_signature = 0;
 995         while (line < tail) {
 996                 const char *sig = NULL;
 997                 const char *next = memchr(line, '\n', tail - line);
 998
 999                 next = next ? next + 1 : tail;
1000                 if (in_signature && line[0] == ' ')
1001                         sig = line + 1;
1002                 else if (starts_with(line, gpg_sig_header) &&
1003                          line[gpg_sig_header_len] == ' ')
1004                         sig = line + gpg_sig_header_len + 1;
1005                 if (sig) {
1006                         strbuf_add(signature, sig, next - sig);
1007                         saw_signature = 1;
1008                         in_signature = 1;
1009                 } else {
1010                         if (*line == '\n')
1011                                 /* dump the whole remainder of the buffer */
1012                                 next = tail;
1013                         strbuf_add(payload, line, next - line);
1014                         in_signature = 0;
1015                 }
1016                 line = next;
1017         }
1018         unuse_commit_buffer(commit, buffer);
1019         return saw_signature;
1020 }
1021
1022 int remove_signature(struct strbuf *buf)
1023 {
1024         const char *line = buf->buf;
1025         const char *tail = buf->buf + buf->len;
1026         int in_signature = 0;
1027         const char *sig_start = NULL;
1028         const char *sig_end = NULL;
1029
1030         while (line < tail) {
1031                 const char *next = memchr(line, '\n', tail - line);
1032                 next = next ? next + 1 : tail;
1033
1034                 if (in_signature && line[0] == ' ')
1035                         sig_end = next;
1036                 else if (starts_with(line, gpg_sig_header) &&
1037                          line[gpg_sig_header_len] == ' ') {
1038                         sig_start = line;
1039                         sig_end = next;
1040                         in_signature = 1;
1041                 } else {
1042                         if (*line == '\n')
1043                                 /* dump the whole remainder of the buffer */
1044                                 next = tail;
1045                         in_signature = 0;
1046                 }
1047                 line = next;
1048         }
1049
1050         if (sig_start)
1051                 strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1052
1053         return sig_start != NULL;
1054 }
1055
1056 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1057 {
1058         struct merge_remote_desc *desc;
1059         struct commit_extra_header *mergetag;
1060         char *buf;
1061         unsigned long size, len;
1062         enum object_type type;
1063
1064         desc = merge_remote_util(parent);
1065         if (!desc || !desc->obj)
1066                 return;
1067         buf = read_object_file(&desc->obj->oid, &type, &size);
1068         if (!buf || type != OBJ_TAG)
1069                 goto free_return;
1070         len = parse_signature(buf, size);
1071         if (size == len)
1072                 goto free_return;
1073         /*
1074          * We could verify this signature and either omit the tag when
1075          * it does not validate, but the integrator may not have the
1076          * public key of the signer of the tag he is merging, while a
1077          * later auditor may have it while auditing, so let's not run
1078          * verify-signed-buffer here for now...
1079          *
1080          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1081          *      warn("warning: signed tag unverified.");
1082          */
1083         mergetag = xcalloc(1, sizeof(*mergetag));
1084         mergetag->key = xstrdup("mergetag");
1085         mergetag->value = buf;
1086         mergetag->len = size;
1087
1088         **tail = mergetag;
1089         *tail = &mergetag->next;
1090         return;
1091
1092 free_return:
1093         free(buf);
1094 }
1095
1096 int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1097 {
1098         struct strbuf payload = STRBUF_INIT;
1099         struct strbuf signature = STRBUF_INIT;
1100         int ret = 1;
1101
1102         sigc->result = 'N';
1103
1104         if (parse_signed_commit(commit, &payload, &signature) <= 0)
1105                 goto out;
1106         ret = check_signature(payload.buf, payload.len, signature.buf,
1107                 signature.len, sigc);
1108
1109  out:
1110         strbuf_release(&payload);
1111         strbuf_release(&signature);
1112
1113         return ret;
1114 }
1115
1116 void verify_merge_signature(struct commit *commit, int verbosity)
1117 {
1118         char hex[GIT_MAX_HEXSZ + 1];
1119         struct signature_check signature_check;
1120         memset(&signature_check, 0, sizeof(signature_check));
1121
1122         check_commit_signature(commit, &signature_check);
1123
1124         find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1125         switch (signature_check.result) {
1126         case 'G':
1127                 break;
1128         case 'U':
1129                 die(_("Commit %s has an untrusted GPG signature, "
1130                       "allegedly by %s."), hex, signature_check.signer);
1131         case 'B':
1132                 die(_("Commit %s has a bad GPG signature "
1133                       "allegedly by %s."), hex, signature_check.signer);
1134         default: /* 'N' */
1135                 die(_("Commit %s does not have a GPG signature."), hex);
1136         }
1137         if (verbosity >= 0 && signature_check.result == 'G')
1138                 printf(_("Commit %s has a good GPG signature by %s\n"),
1139                        hex, signature_check.signer);
1140
1141         signature_check_clear(&signature_check);
1142 }
1143
1144 void append_merge_tag_headers(struct commit_list *parents,
1145                               struct commit_extra_header ***tail)
1146 {
1147         while (parents) {
1148                 struct commit *parent = parents->item;
1149                 handle_signed_tag(parent, tail);
1150                 parents = parents->next;
1151         }
1152 }
1153
1154 static void add_extra_header(struct strbuf *buffer,
1155                              struct commit_extra_header *extra)
1156 {
1157         strbuf_addstr(buffer, extra->key);
1158         if (extra->len)
1159                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1160         else
1161                 strbuf_addch(buffer, '\n');
1162 }
1163
1164 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1165                                                       const char **exclude)
1166 {
1167         struct commit_extra_header *extra = NULL;
1168         unsigned long size;
1169         const char *buffer = get_commit_buffer(commit, &size);
1170         extra = read_commit_extra_header_lines(buffer, size, exclude);
1171         unuse_commit_buffer(commit, buffer);
1172         return extra;
1173 }
1174
1175 int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1176 {
1177         struct commit_extra_header *extra, *to_free;
1178         int res = 0;
1179
1180         to_free = read_commit_extra_headers(commit, NULL);
1181         for (extra = to_free; !res && extra; extra = extra->next) {
1182                 if (strcmp(extra->key, "mergetag"))
1183                         continue; /* not a merge tag */
1184                 res = fn(commit, extra, data);
1185         }
1186         free_commit_extra_headers(to_free);
1187         return res;
1188 }
1189
1190 static inline int standard_header_field(const char *field, size_t len)
1191 {
1192         return ((len == 4 && !memcmp(field, "tree", 4)) ||
1193                 (len == 6 && !memcmp(field, "parent", 6)) ||
1194                 (len == 6 && !memcmp(field, "author", 6)) ||
1195                 (len == 9 && !memcmp(field, "committer", 9)) ||
1196                 (len == 8 && !memcmp(field, "encoding", 8)));
1197 }
1198
1199 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1200 {
1201         if (!exclude)
1202                 return 0;
1203
1204         while (*exclude) {
1205                 size_t xlen = strlen(*exclude);
1206                 if (len == xlen && !memcmp(field, *exclude, xlen))
1207                         return 1;
1208                 exclude++;
1209         }
1210         return 0;
1211 }
1212
1213 static struct commit_extra_header *read_commit_extra_header_lines(
1214         const char *buffer, size_t size,
1215         const char **exclude)
1216 {
1217         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1218         const char *line, *next, *eof, *eob;
1219         struct strbuf buf = STRBUF_INIT;
1220
1221         for (line = buffer, eob = line + size;
1222              line < eob && *line != '\n';
1223              line = next) {
1224                 next = memchr(line, '\n', eob - line);
1225                 next = next ? next + 1 : eob;
1226                 if (*line == ' ') {
1227                         /* continuation */
1228                         if (it)
1229                                 strbuf_add(&buf, line + 1, next - (line + 1));
1230                         continue;
1231                 }
1232                 if (it)
1233                         it->value = strbuf_detach(&buf, &it->len);
1234                 strbuf_reset(&buf);
1235                 it = NULL;
1236
1237                 eof = memchr(line, ' ', next - line);
1238                 if (!eof)
1239                         eof = next;
1240                 else if (standard_header_field(line, eof - line) ||
1241                          excluded_header_field(line, eof - line, exclude))
1242                         continue;
1243
1244                 it = xcalloc(1, sizeof(*it));
1245                 it->key = xmemdupz(line, eof-line);
1246                 *tail = it;
1247                 tail = &it->next;
1248                 if (eof + 1 < next)
1249                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1250         }
1251         if (it)
1252                 it->value = strbuf_detach(&buf, &it->len);
1253         return extra;
1254 }
1255
1256 void free_commit_extra_headers(struct commit_extra_header *extra)
1257 {
1258         while (extra) {
1259                 struct commit_extra_header *next = extra->next;
1260                 free(extra->key);
1261                 free(extra->value);
1262                 free(extra);
1263                 extra = next;
1264         }
1265 }
1266
1267 int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
1268                 struct commit_list *parents, struct object_id *ret,
1269                 const char *author, const char *sign_commit)
1270 {
1271         struct commit_extra_header *extra = NULL, **tail = &extra;
1272         int result;
1273
1274         append_merge_tag_headers(parents, &tail);
1275         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1276                                       author, sign_commit, extra);
1277         free_commit_extra_headers(extra);
1278         return result;
1279 }
1280
1281 static int find_invalid_utf8(const char *buf, int len)
1282 {
1283         int offset = 0;
1284         static const unsigned int max_codepoint[] = {
1285                 0x7f, 0x7ff, 0xffff, 0x10ffff
1286         };
1287
1288         while (len) {
1289                 unsigned char c = *buf++;
1290                 int bytes, bad_offset;
1291                 unsigned int codepoint;
1292                 unsigned int min_val, max_val;
1293
1294                 len--;
1295                 offset++;
1296
1297                 /* Simple US-ASCII? No worries. */
1298                 if (c < 0x80)
1299                         continue;
1300
1301                 bad_offset = offset-1;
1302
1303                 /*
1304                  * Count how many more high bits set: that's how
1305                  * many more bytes this sequence should have.
1306                  */
1307                 bytes = 0;
1308                 while (c & 0x40) {
1309                         c <<= 1;
1310                         bytes++;
1311                 }
1312
1313                 /*
1314                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1315                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1316                  */
1317                 if (bytes < 1 || 3 < bytes)
1318                         return bad_offset;
1319
1320                 /* Do we *have* that many bytes? */
1321                 if (len < bytes)
1322                         return bad_offset;
1323
1324                 /*
1325                  * Place the encoded bits at the bottom of the value and compute the
1326                  * valid range.
1327                  */
1328                 codepoint = (c & 0x7f) >> bytes;
1329                 min_val = max_codepoint[bytes-1] + 1;
1330                 max_val = max_codepoint[bytes];
1331
1332                 offset += bytes;
1333                 len -= bytes;
1334
1335                 /* And verify that they are good continuation bytes */
1336                 do {
1337                         codepoint <<= 6;
1338                         codepoint |= *buf & 0x3f;
1339                         if ((*buf++ & 0xc0) != 0x80)
1340                                 return bad_offset;
1341                 } while (--bytes);
1342
1343                 /* Reject codepoints that are out of range for the sequence length. */
1344                 if (codepoint < min_val || codepoint > max_val)
1345                         return bad_offset;
1346                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1347                 if ((codepoint & 0x1ff800) == 0xd800)
1348                         return bad_offset;
1349                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1350                 if ((codepoint & 0xfffe) == 0xfffe)
1351                         return bad_offset;
1352                 /* So are anything in the range U+FDD0..U+FDEF. */
1353                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1354                         return bad_offset;
1355         }
1356         return -1;
1357 }
1358
1359 /*
1360  * This verifies that the buffer is in proper utf8 format.
1361  *
1362  * If it isn't, it assumes any non-utf8 characters are Latin1,
1363  * and does the conversion.
1364  */
1365 static int verify_utf8(struct strbuf *buf)
1366 {
1367         int ok = 1;
1368         long pos = 0;
1369
1370         for (;;) {
1371                 int bad;
1372                 unsigned char c;
1373                 unsigned char replace[2];
1374
1375                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1376                 if (bad < 0)
1377                         return ok;
1378                 pos += bad;
1379                 ok = 0;
1380                 c = buf->buf[pos];
1381                 strbuf_remove(buf, pos, 1);
1382
1383                 /* We know 'c' must be in the range 128-255 */
1384                 replace[0] = 0xc0 + (c >> 6);
1385                 replace[1] = 0x80 + (c & 0x3f);
1386                 strbuf_insert(buf, pos, replace, 2);
1387                 pos += 2;
1388         }
1389 }
1390
1391 static const char commit_utf8_warn[] =
1392 N_("Warning: commit message did not conform to UTF-8.\n"
1393    "You may want to amend it after fixing the message, or set the config\n"
1394    "variable i18n.commitencoding to the encoding your project uses.\n");
1395
1396 int commit_tree_extended(const char *msg, size_t msg_len,
1397                          const struct object_id *tree,
1398                          struct commit_list *parents, struct object_id *ret,
1399                          const char *author, const char *sign_commit,
1400                          struct commit_extra_header *extra)
1401 {
1402         int result;
1403         int encoding_is_utf8;
1404         struct strbuf buffer;
1405
1406         assert_oid_type(tree, OBJ_TREE);
1407
1408         if (memchr(msg, '\0', msg_len))
1409                 return error("a NUL byte in commit log message not allowed.");
1410
1411         /* Not having i18n.commitencoding is the same as having utf-8 */
1412         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1413
1414         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1415         strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
1416
1417         /*
1418          * NOTE! This ordering means that the same exact tree merged with a
1419          * different order of parents will be a _different_ changeset even
1420          * if everything else stays the same.
1421          */
1422         while (parents) {
1423                 struct commit *parent = pop_commit(&parents);
1424                 strbuf_addf(&buffer, "parent %s\n",
1425                             oid_to_hex(&parent->object.oid));
1426         }
1427
1428         /* Person/date information */
1429         if (!author)
1430                 author = git_author_info(IDENT_STRICT);
1431         strbuf_addf(&buffer, "author %s\n", author);
1432         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1433         if (!encoding_is_utf8)
1434                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1435
1436         while (extra) {
1437                 add_extra_header(&buffer, extra);
1438                 extra = extra->next;
1439         }
1440         strbuf_addch(&buffer, '\n');
1441
1442         /* And add the comment */
1443         strbuf_add(&buffer, msg, msg_len);
1444
1445         /* And check the encoding */
1446         if (encoding_is_utf8 && !verify_utf8(&buffer))
1447                 fprintf(stderr, _(commit_utf8_warn));
1448
1449         if (sign_commit && do_sign_commit(&buffer, sign_commit)) {
1450                 result = -1;
1451                 goto out;
1452         }
1453
1454         result = write_object_file(buffer.buf, buffer.len, commit_type, ret);
1455 out:
1456         strbuf_release(&buffer);
1457         return result;
1458 }
1459
1460 define_commit_slab(merge_desc_slab, struct merge_remote_desc *);
1461 static struct merge_desc_slab merge_desc_slab = COMMIT_SLAB_INIT(1, merge_desc_slab);
1462
1463 struct merge_remote_desc *merge_remote_util(struct commit *commit)
1464 {
1465         return *merge_desc_slab_at(&merge_desc_slab, commit);
1466 }
1467
1468 void set_merge_remote_desc(struct commit *commit,
1469                            const char *name, struct object *obj)
1470 {
1471         struct merge_remote_desc *desc;
1472         FLEX_ALLOC_STR(desc, name, name);
1473         desc->obj = obj;
1474         *merge_desc_slab_at(&merge_desc_slab, commit) = desc;
1475 }
1476
1477 struct commit *get_merge_parent(const char *name)
1478 {
1479         struct object *obj;
1480         struct commit *commit;
1481         struct object_id oid;
1482         if (get_oid(name, &oid))
1483                 return NULL;
1484         obj = parse_object(the_repository, &oid);
1485         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1486         if (commit && !merge_remote_util(commit))
1487                 set_merge_remote_desc(commit, name, obj);
1488         return commit;
1489 }
1490
1491 /*
1492  * Append a commit to the end of the commit_list.
1493  *
1494  * next starts by pointing to the variable that holds the head of an
1495  * empty commit_list, and is updated to point to the "next" field of
1496  * the last item on the list as new commits are appended.
1497  *
1498  * Usage example:
1499  *
1500  *     struct commit_list *list;
1501  *     struct commit_list **next = &list;
1502  *
1503  *     next = commit_list_append(c1, next);
1504  *     next = commit_list_append(c2, next);
1505  *     assert(commit_list_count(list) == 2);
1506  *     return list;
1507  */
1508 struct commit_list **commit_list_append(struct commit *commit,
1509                                         struct commit_list **next)
1510 {
1511         struct commit_list *new_commit = xmalloc(sizeof(struct commit_list));
1512         new_commit->item = commit;
1513         *next = new_commit;
1514         new_commit->next = NULL;
1515         return &new_commit->next;
1516 }
1517
1518 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1519 {
1520         int key_len = strlen(key);
1521         const char *line = msg;
1522
1523         while (line) {
1524                 const char *eol = strchrnul(line, '\n');
1525
1526                 if (line == eol)
1527                         return NULL;
1528
1529                 if (eol - line > key_len &&
1530                     !strncmp(line, key, key_len) &&
1531                     line[key_len] == ' ') {
1532                         *out_len = eol - line - key_len - 1;
1533                         return line + key_len + 1;
1534                 }
1535                 line = *eol ? eol + 1 : NULL;
1536         }
1537         return NULL;
1538 }
1539
1540 /*
1541  * Inspect the given string and determine the true "end" of the log message, in
1542  * order to find where to put a new Signed-off-by: line.  Ignored are
1543  * trailing comment lines and blank lines.  To support "git commit -s
1544  * --amend" on an existing commit, we also ignore "Conflicts:".  To
1545  * support "git commit -v", we truncate at cut lines.
1546  *
1547  * Returns the number of bytes from the tail to ignore, to be fed as
1548  * the second parameter to append_signoff().
1549  */
1550 size_t ignore_non_trailer(const char *buf, size_t len)
1551 {
1552         size_t boc = 0;
1553         size_t bol = 0;
1554         int in_old_conflicts_block = 0;
1555         size_t cutoff = wt_status_locate_end(buf, len);
1556
1557         while (bol < cutoff) {
1558                 const char *next_line = memchr(buf + bol, '\n', len - bol);
1559
1560                 if (!next_line)
1561                         next_line = buf + len;
1562                 else
1563                         next_line++;
1564
1565                 if (buf[bol] == comment_line_char || buf[bol] == '\n') {
1566                         /* is this the first of the run of comments? */
1567                         if (!boc)
1568                                 boc = bol;
1569                         /* otherwise, it is just continuing */
1570                 } else if (starts_with(buf + bol, "Conflicts:\n")) {
1571                         in_old_conflicts_block = 1;
1572                         if (!boc)
1573                                 boc = bol;
1574                 } else if (in_old_conflicts_block && buf[bol] == '\t') {
1575                         ; /* a pathname in the conflicts block */
1576                 } else if (boc) {
1577                         /* the previous was not trailing comment */
1578                         boc = 0;
1579                         in_old_conflicts_block = 0;
1580                 }
1581                 bol = next_line - buf;
1582         }
1583         return boc ? len - boc : len - cutoff;
1584 }
1585
1586 int run_commit_hook(int editor_is_used, const char *index_file,
1587                     const char *name, ...)
1588 {
1589         struct argv_array hook_env = ARGV_ARRAY_INIT;
1590         va_list args;
1591         int ret;
1592
1593         argv_array_pushf(&hook_env, "GIT_INDEX_FILE=%s", index_file);
1594
1595         /*
1596          * Let the hook know that no editor will be launched.
1597          */
1598         if (!editor_is_used)
1599                 argv_array_push(&hook_env, "GIT_EDITOR=:");
1600
1601         va_start(args, name);
1602         ret = run_hook_ve(hook_env.argv,name, args);
1603         va_end(args);
1604         argv_array_clear(&hook_env);
1605
1606         return ret;
1607 }