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