git.oblomov.eu Git - git/blob - 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
  21 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  22
  23 int save_commit_buffer = 1;
  24
  25 const char *commit_type = "commit";
  26
  27 struct commit *lookup_commit_reference_gently(struct repository *r,
  28                 const struct object_id *oid, int quiet)
  29 {
  30         struct object *obj = deref_tag(r,
  31                                        parse_object(r, oid),
  32                                        NULL, 0);
  33
  34         if (!obj)
  35                 return NULL;
  36         return object_as_type(r, obj, OBJ_COMMIT, quiet);
  37 }
  38
  39 struct commit *lookup_commit_reference_the_repository(const struct object_id *oid)
  40 {
  41         return lookup_commit_reference_gently(the_repository, oid, 0);
  42 }
  43
  44 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
  45 {
  46         struct commit *c = lookup_commit_reference(the_repository, oid);
  47         if (!c)
  48                 die(_("could not parse %s"), ref_name);
  49         if (oidcmp(oid, &c->object.oid)) {
  50                 warning(_("%s %s is not a commit!"),
  51                         ref_name, oid_to_hex(oid));
  52         }
  53         return c;
  54 }
  55
  56 struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
  57 {
  58         struct object *obj = lookup_object(r, oid->hash);
  59         if (!obj)
  60                 return create_object(r, oid->hash,
  61                                      alloc_commit_node(r));
  62         return object_as_type(r, obj, OBJ_COMMIT, 0);
  63 }
  64
  65 struct commit *lookup_commit_reference_by_name(const char *name)
  66 {
  67         struct object_id oid;
  68         struct commit *commit;
  69
  70         if (get_oid_committish(name, &oid))
  71                 return NULL;
  72         commit = lookup_commit_reference(the_repository, &oid);
  73         if (parse_commit(commit))
  74                 return NULL;
  75         return commit;
  76 }
  77
  78 static timestamp_t parse_commit_date(const char *buf, const char *tail)
  79 {
  80         const char *dateptr;
  81
  82         if (buf + 6 >= tail)
  83                 return 0;
  84         if (memcmp(buf, "author", 6))
  85                 return 0;
  86         while (buf < tail && *buf++ != '\n')
  87                 /* nada */;
  88         if (buf + 9 >= tail)
  89                 return 0;
  90         if (memcmp(buf, "committer", 9))
  91                 return 0;
  92         while (buf < tail && *buf++ != '>')
  93                 /* nada */;
  94         if (buf >= tail)
  95                 return 0;
  96         dateptr = buf;
  97         while (buf < tail && *buf++ != '\n')
  98                 /* nada */;
  99         if (buf >= tail)
 100                 return 0;
 101         /* dateptr < buf && buf[-1] == '\n', so parsing will stop at buf-1 */
 102         return parse_timestamp(dateptr, NULL, 10);
 103 }
 104
 105 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 106 {
 107         struct commit_graft **commit_graft_table = table;
 108         return commit_graft_table[index]->oid.hash;
 109 }
 110
 111 static int commit_graft_pos(struct repository *r, const unsigned char *sha1)
 112 {
 113         return sha1_pos(sha1, r->parsed_objects->grafts,
 114                         r->parsed_objects->grafts_nr,
 115                         commit_graft_sha1_access);
 116 }
 117
 118 int register_commit_graft(struct repository *r, struct commit_graft *graft,
 119                           int ignore_dups)
 120 {
 121         int pos = commit_graft_pos(r, graft->oid.hash);
 122
 123         if (0 <= pos) {
 124                 if (ignore_dups)
 125                         free(graft);
 126                 else {
 127                         free(r->parsed_objects->grafts[pos]);
 128                         r->parsed_objects->grafts[pos] = graft;
 129                 }
 130                 return 1;
 131         }
 132         pos = -pos - 1;
 133         ALLOC_GROW(r->parsed_objects->grafts,
 134                    r->parsed_objects->grafts_nr + 1,
 135                    r->parsed_objects->grafts_alloc);
 136         r->parsed_objects->grafts_nr++;
 137         if (pos < r->parsed_objects->grafts_nr)
 138                 memmove(r->parsed_objects->grafts + pos + 1,
 139                         r->parsed_objects->grafts + pos,
 140                         (r->parsed_objects->grafts_nr - pos - 1) *
 141                         sizeof(*r->parsed_objects->grafts));
 142         r->parsed_objects->grafts[pos] = graft;
 143         return 0;
 144 }
 145
 146 struct commit_graft *read_graft_line(struct strbuf *line)
 147 {
 148         /* The format is just "Commit Parent1 Parent2 ...\n" */
 149         int i, phase;
 150         const char *tail = NULL;
 151         struct commit_graft *graft = NULL;
 152         struct object_id dummy_oid, *oid;
 153
 154         strbuf_rtrim(line);
 155         if (!line->len || line->buf[0] == '#')
 156                 return NULL;
 157         /*
 158          * phase 0 verifies line, counts hashes in line and allocates graft
 159          * phase 1 fills graft
 160          */
 161         for (phase = 0; phase < 2; phase++) {
 162                 oid = graft ? &graft->oid : &dummy_oid;
 163                 if (parse_oid_hex(line->buf, oid, &tail))
 164                         goto bad_graft_data;
 165                 for (i = 0; *tail != '\0'; i++) {
 166                         oid = graft ? &graft->parent[i] : &dummy_oid;
 167                         if (!isspace(*tail++) || parse_oid_hex(tail, oid, &tail))
 168                                 goto bad_graft_data;
 169                 }
 170                 if (!graft) {
 171                         graft = xmalloc(st_add(sizeof(*graft),
 172                                                st_mult(sizeof(struct object_id), i)));
 173                         graft->nr_parent = i;
 174                 }
 175         }
 176         return graft;
 177
 178 bad_graft_data:
 179         error("bad graft data: %s", line->buf);
 180         assert(!graft);
 181         return NULL;
 182 }
 183
 184 static int read_graft_file(struct repository *r, const char *graft_file)
 185 {
 186         FILE *fp = fopen_or_warn(graft_file, "r");
 187         struct strbuf buf = STRBUF_INIT;
 188         if (!fp)
 189                 return -1;
 190         if (advice_graft_file_deprecated)
 191                 advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
 192                          "and will be removed in a future Git version.\n"
 193                          "\n"
 194                          "Please use \"git replace --convert-graft-file\"\n"
 195                          "to convert the grafts into replace refs.\n"
 196                          "\n"
 197                          "Turn this message off by running\n"
 198                          "\"git config advice.graftFileDeprecated false\""));
 199         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 200                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 201                 struct commit_graft *graft = read_graft_line(&buf);
 202                 if (!graft)
 203                         continue;
 204                 if (register_commit_graft(r, graft, 1))
 205                         error("duplicate graft data: %s", buf.buf);
 206         }
 207         fclose(fp);
 208         strbuf_release(&buf);
 209         return 0;
 210 }
 211
 212 static void prepare_commit_graft(struct repository *r)
 213 {
 214         char *graft_file;
 215
 216         if (r->parsed_objects->commit_graft_prepared)
 217                 return;
 218         if (!startup_info->have_repository)
 219                 return;
 220
 221         graft_file = get_graft_file(r);
 222         read_graft_file(r, graft_file);
 223         /* make sure shallows are read */
 224         is_repository_shallow(r);
 225         r->parsed_objects->commit_graft_prepared = 1;
 226 }
 227
 228 struct commit_graft *lookup_commit_graft(struct repository *r, const struct object_id *oid)
 229 {
 230         int pos;
 231         prepare_commit_graft(r);
 232         pos = commit_graft_pos(r, oid->hash);
 233         if (pos < 0)
 234                 return NULL;
 235         return r->parsed_objects->grafts[pos];
 236 }
 237
 238 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 239 {
 240         int i, ret;
 241         for (i = ret = 0; i < the_repository->parsed_objects->grafts_nr && !ret; i++)
 242                 ret = fn(the_repository->parsed_objects->grafts[i], cb_data);
 243         return ret;
 244 }
 245
 246 int unregister_shallow(const struct object_id *oid)
 247 {
 248         int pos = commit_graft_pos(the_repository, oid->hash);
 249         if (pos < 0)
 250                 return -1;
 251         if (pos + 1 < the_repository->parsed_objects->grafts_nr)
 252                 MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
 253                            the_repository->parsed_objects->grafts + pos + 1,
 254                            the_repository->parsed_objects->grafts_nr - pos - 1);
 255         the_repository->parsed_objects->grafts_nr--;
 256         return 0;
 257 }
 258
 259 struct commit_buffer {
 260         void *buffer;
 261         unsigned long size;
 262 };
 263 define_commit_slab(buffer_slab, struct commit_buffer);
 264
 265 struct buffer_slab *allocate_commit_buffer_slab(void)
 266 {
 267         struct buffer_slab *bs = xmalloc(sizeof(*bs));
 268         init_buffer_slab(bs);
 269         return bs;
 270 }
 271
 272 void free_commit_buffer_slab(struct buffer_slab *bs)
 273 {
 274         clear_buffer_slab(bs);
 275         free(bs);
 276 }
 277
 278 void set_commit_buffer(struct repository *r, struct commit *commit, void *buffer, unsigned long size)
 279 {
 280         struct commit_buffer *v = buffer_slab_at(
 281                 r->parsed_objects->buffer_slab, commit);
 282         v->buffer = buffer;
 283         v->size = size;
 284 }
 285
 286 const void *get_cached_commit_buffer(struct repository *r, const struct commit *commit, unsigned long *sizep)
 287 {
 288         struct commit_buffer *v = buffer_slab_peek(
 289                 r->parsed_objects->buffer_slab, commit);
 290         if (!v) {
 291                 if (sizep)
 292                         *sizep = 0;
 293                 return NULL;
 294         }
 295         if (sizep)
 296                 *sizep = v->size;
 297         return v->buffer;
 298 }
 299
 300 const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 301 {
 302         const void *ret = get_cached_commit_buffer(the_repository, commit, sizep);
 303         if (!ret) {
 304                 enum object_type type;
 305                 unsigned long size;
 306                 ret = read_object_file(&commit->object.oid, &type, &size);
 307                 if (!ret)
 308                         die("cannot read commit object %s",
 309                             oid_to_hex(&commit->object.oid));
 310                 if (type != OBJ_COMMIT)
 311                         die("expected commit for %s, got %s",
 312                             oid_to_hex(&commit->object.oid), type_name(type));
 313                 if (sizep)
 314                         *sizep = size;
 315         }
 316         return ret;
 317 }
 318
 319 void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 320 {
 321         struct commit_buffer *v = buffer_slab_peek(
 322                 the_repository->parsed_objects->buffer_slab, commit);
 323         if (!(v && v->buffer == buffer))
 324                 free((void *)buffer);
 325 }
 326
 327 void free_commit_buffer(struct commit *commit)
 328 {
 329         struct commit_buffer *v = buffer_slab_peek(
 330                 the_repository->parsed_objects->buffer_slab, commit);
 331         if (v) {
 332                 FREE_AND_NULL(v->buffer);
 333                 v->size = 0;
 334         }
 335 }
 336
 337 struct tree *get_commit_tree(const struct commit *commit)
 338 {
 339         if (commit->maybe_tree || !commit->object.parsed)
 340                 return commit->maybe_tree;
 341
 342         if (commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
 343                 BUG("commit has NULL tree, but was not loaded from commit-graph");
 344
 345         return get_commit_tree_in_graph(commit);
 346 }
 347
 348 struct object_id *get_commit_tree_oid(const struct commit *commit)
 349 {
 350         return &get_commit_tree(commit)->object.oid;
 351 }
 352
 353 void release_commit_memory(struct commit *c)
 354 {
 355         c->maybe_tree = NULL;
 356         c->index = 0;
 357         free_commit_buffer(c);
 358         free_commit_list(c->parents);
 359         /* TODO: what about commit->util? */
 360
 361         c->object.parsed = 0;
 362 }
 363
 364 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 365 {
 366         struct commit_buffer *v = buffer_slab_peek(
 367                 the_repository->parsed_objects->buffer_slab, commit);
 368         void *ret;
 369
 370         if (!v) {
 371                 if (sizep)
 372                         *sizep = 0;
 373                 return NULL;
 374         }
 375         ret = v->buffer;
 376         if (sizep)
 377                 *sizep = v->size;
 378
 379         v->buffer = NULL;
 380         v->size = 0;
 381         return ret;
 382 }
 383
 384 int parse_commit_buffer(struct repository *r, struct commit *item, const void *buffer, unsigned long size, int check_graph)
 385 {
 386         const char *tail = buffer;
 387         const char *bufptr = buffer;
 388         struct object_id parent;
 389         struct commit_list **pptr;
 390         struct commit_graft *graft;
 391         const int tree_entry_len = GIT_SHA1_HEXSZ + 5;
 392         const int parent_entry_len = GIT_SHA1_HEXSZ + 7;
 393
 394         if (item->object.parsed)
 395                 return 0;
 396         item->object.parsed = 1;
 397         tail += size;
 398         if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 399                         bufptr[tree_entry_len] != '\n')
 400                 return error("bogus commit object %s", oid_to_hex(&item->object.oid));
 401         if (get_oid_hex(bufptr + 5, &parent) < 0)
 402                 return error("bad tree pointer in commit %s",
 403                              oid_to_hex(&item->object.oid));
 404         item->maybe_tree = lookup_tree(r, &parent);
 405         bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 406         pptr = &item->parents;
 407
 408         graft = lookup_commit_graft(r, &item->object.oid);
 409         while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 410                 struct commit *new_parent;
 411
 412                 if (tail <= bufptr + parent_entry_len + 1 ||
 413                     get_oid_hex(bufptr + 7, &parent) ||
 414                     bufptr[parent_entry_len] != '\n')
 415                         return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
 416                 bufptr += parent_entry_len + 1;
 417                 /*
 418                  * The clone is shallow if nr_parent < 0, and we must
 419                  * not traverse its real parents even when we unhide them.
 420                  */
 421                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 422                         continue;
 423                 new_parent = lookup_commit(r, &parent);
 424                 if (new_parent)
 425                         pptr = &commit_list_insert(new_parent, pptr)->next;
 426         }
 427         if (graft) {
 428                 int i;
 429                 struct commit *new_parent;
 430                 for (i = 0; i < graft->nr_parent; i++) {
 431                         new_parent = lookup_commit(r,
 432                                                    &graft->parent[i]);
 433                         if (!new_parent)
 434                                 continue;
 435                         pptr = &commit_list_insert(new_parent, pptr)->next;
 436                 }
 437         }
 438         item->date = parse_commit_date(bufptr, tail);
 439
 440         if (check_graph)
 441                 load_commit_graph_info(item);
 442
 443         return 0;
 444 }
 445
 446 int parse_commit_gently(struct commit *item, int quiet_on_missing)
 447 {
 448         enum object_type type;
 449         void *buffer;
 450         unsigned long size;
 451         int ret;
 452
 453         if (!item)
 454                 return -1;
 455         if (item->object.parsed)
 456                 return 0;
 457         if (parse_commit_in_graph(item))
 458                 return 0;
 459         buffer = read_object_file(&item->object.oid, &type, &size);
 460         if (!buffer)
 461                 return quiet_on_missing ? -1 :
 462                         error("Could not read %s",
 463                              oid_to_hex(&item->object.oid));
 464         if (type != OBJ_COMMIT) {
 465                 free(buffer);
 466                 return error("Object %s not a commit",
 467                              oid_to_hex(&item->object.oid));
 468         }
 469         ret = parse_commit_buffer(the_repository, item, buffer, size, 0);
 470         if (save_commit_buffer && !ret) {
 471                 set_commit_buffer(the_repository, item, buffer, size);
 472                 return 0;
 473         }
 474         free(buffer);
 475         return ret;
 476 }
 477
 478 void parse_commit_or_die(struct commit *item)
 479 {
 480         if (parse_commit(item))
 481                 die("unable to parse commit %s",
 482                     item ? oid_to_hex(&item->object.oid) : "(null)");
 483 }
 484
 485 int find_commit_subject(const char *commit_buffer, const char **subject)
 486 {
 487         const char *eol;
 488         const char *p = commit_buffer;
 489
 490         while (*p && (*p != '\n' || p[1] != '\n'))
 491                 p++;
 492         if (*p) {
 493                 p = skip_blank_lines(p + 2);
 494                 eol = strchrnul(p, '\n');
 495         } else
 496                 eol = p;
 497
 498         *subject = p;
 499
 500         return eol - p;
 501 }
 502
 503 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 504 {
 505         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 506         new_list->item = item;
 507         new_list->next = *list_p;
 508         *list_p = new_list;
 509         return new_list;
 510 }
 511
 512 unsigned commit_list_count(const struct commit_list *l)
 513 {
 514         unsigned c = 0;
 515         for (; l; l = l->next )
 516                 c++;
 517         return c;
 518 }
 519
 520 struct commit_list *copy_commit_list(struct commit_list *list)
 521 {
 522         struct commit_list *head = NULL;
 523         struct commit_list **pp = &head;
 524         while (list) {
 525                 pp = commit_list_append(list->item, pp);
 526                 list = list->next;
 527         }
 528         return head;
 529 }
 530
 531 void free_commit_list(struct commit_list *list)
 532 {
 533         while (list)
 534                 pop_commit(&list);
 535 }
 536
 537 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 538 {
 539         struct commit_list **pp = list;
 540         struct commit_list *p;
 541         while ((p = *pp) != NULL) {
 542                 if (p->item->date < item->date) {
 543                         break;
 544                 }
 545                 pp = &p->next;
 546         }
 547         return commit_list_insert(item, pp);
 548 }
 549
 550 static int commit_list_compare_by_date(const void *a, const void *b)
 551 {
 552         timestamp_t a_date = ((const struct commit_list *)a)->item->date;
 553         timestamp_t b_date = ((const struct commit_list *)b)->item->date;
 554         if (a_date < b_date)
 555                 return 1;
 556         if (a_date > b_date)
 557                 return -1;
 558         return 0;
 559 }
 560
 561 static void *commit_list_get_next(const void *a)
 562 {
 563         return ((const struct commit_list *)a)->next;
 564 }
 565
 566 static void commit_list_set_next(void *a, void *next)
 567 {
 568         ((struct commit_list *)a)->next = next;
 569 }
 570
 571 void commit_list_sort_by_date(struct commit_list **list)
 572 {
 573         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 574                                 commit_list_compare_by_date);
 575 }
 576
 577 struct commit *pop_most_recent_commit(struct commit_list **list,
 578                                       unsigned int mark)
 579 {
 580         struct commit *ret = pop_commit(list);
 581         struct commit_list *parents = ret->parents;
 582
 583         while (parents) {
 584                 struct commit *commit = parents->item;
 585                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 586                         commit->object.flags |= mark;
 587                         commit_list_insert_by_date(commit, list);
 588                 }
 589                 parents = parents->next;
 590         }
 591         return ret;
 592 }
 593
 594 static void clear_commit_marks_1(struct commit_list **plist,
 595                                  struct commit *commit, unsigned int mark)
 596 {
 597         while (commit) {
 598                 struct commit_list *parents;
 599
 600                 if (!(mark & commit->object.flags))
 601                         return;
 602
 603                 commit->object.flags &= ~mark;
 604
 605                 parents = commit->parents;
 606                 if (!parents)
 607                         return;
 608
 609                 while ((parents = parents->next))
 610                         commit_list_insert(parents->item, plist);
 611
 612                 commit = commit->parents->item;
 613         }
 614 }
 615
 616 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 617 {
 618         struct commit_list *list = NULL;
 619
 620         while (nr--) {
 621                 clear_commit_marks_1(&list, *commit, mark);
 622                 commit++;
 623         }
 624         while (list)
 625                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 626 }
 627
 628 void clear_commit_marks(struct commit *commit, unsigned int mark)
 629 {
 630         clear_commit_marks_many(1, &commit, mark);
 631 }
 632
 633 struct commit *pop_commit(struct commit_list **stack)
 634 {
 635         struct commit_list *top = *stack;
 636         struct commit *item = top ? top->item : NULL;
 637
 638         if (top) {
 639                 *stack = top->next;
 640                 free(top);
 641         }
 642         return item;
 643 }
 644
 645 /*
 646  * Topological sort support
 647  */
 648
 649 /* count number of children that have not been emitted */
 650 define_commit_slab(indegree_slab, int);
 651
 652 /* record author-date for each commit object */
 653 define_commit_slab(author_date_slab, unsigned long);
 654
 655 static void record_author_date(struct author_date_slab *author_date,
 656                                struct commit *commit)
 657 {
 658         const char *buffer = get_commit_buffer(commit, NULL);
 659         struct ident_split ident;
 660         const char *ident_line;
 661         size_t ident_len;
 662         char *date_end;
 663         timestamp_t date;
 664
 665         ident_line = find_commit_header(buffer, "author", &ident_len);
 666         if (!ident_line)
 667                 goto fail_exit; /* no author line */
 668         if (split_ident_line(&ident, ident_line, ident_len) ||
 669             !ident.date_begin || !ident.date_end)
 670                 goto fail_exit; /* malformed "author" line */
 671
 672         date = parse_timestamp(ident.date_begin, &date_end, 10);
 673         if (date_end != ident.date_end)
 674                 goto fail_exit; /* malformed date */
 675         *(author_date_slab_at(author_date, commit)) = date;
 676
 677 fail_exit:
 678         unuse_commit_buffer(commit, buffer);
 679 }
 680
 681 static int compare_commits_by_author_date(const void *a_, const void *b_,
 682                                           void *cb_data)
 683 {
 684         const struct commit *a = a_, *b = b_;
 685         struct author_date_slab *author_date = cb_data;
 686         timestamp_t a_date = *(author_date_slab_at(author_date, a));
 687         timestamp_t b_date = *(author_date_slab_at(author_date, b));
 688
 689         /* newer commits with larger date first */
 690         if (a_date < b_date)
 691                 return 1;
 692         else if (a_date > b_date)
 693                 return -1;
 694         return 0;
 695 }
 696
 697 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
 698 {
 699         const struct commit *a = a_, *b = b_;
 700
 701         /* newer commits first */
 702         if (a->generation < b->generation)
 703                 return 1;
 704         else if (a->generation > b->generation)
 705                 return -1;
 706
 707         /* use date as a heuristic when generations are equal */
 708         if (a->date < b->date)
 709                 return 1;
 710         else if (a->date > b->date)
 711                 return -1;
 712         return 0;
 713 }
 714
 715 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 716 {
 717         const struct commit *a = a_, *b = b_;
 718         /* newer commits with larger date first */
 719         if (a->date < b->date)
 720                 return 1;
 721         else if (a->date > b->date)
 722                 return -1;
 723         return 0;
 724 }
 725
 726 /*
 727  * Performs an in-place topological sort on the list supplied.
 728  */
 729 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 730 {
 731         struct commit_list *next, *orig = *list;
 732         struct commit_list **pptr;
 733         struct indegree_slab indegree;
 734         struct prio_queue queue;
 735         struct commit *commit;
 736         struct author_date_slab author_date;
 737
 738         if (!orig)
 739                 return;
 740         *list = NULL;
 741
 742         init_indegree_slab(&indegree);
 743         memset(&queue, '\0', sizeof(queue));
 744
 745         switch (sort_order) {
 746         default: /* REV_SORT_IN_GRAPH_ORDER */
 747                 queue.compare = NULL;
 748                 break;
 749         case REV_SORT_BY_COMMIT_DATE:
 750                 queue.compare = compare_commits_by_commit_date;
 751                 break;
 752         case REV_SORT_BY_AUTHOR_DATE:
 753                 init_author_date_slab(&author_date);
 754                 queue.compare = compare_commits_by_author_date;
 755                 queue.cb_data = &author_date;
 756                 break;
 757         }
 758
 759         /* Mark them and clear the indegree */
 760         for (next = orig; next; next = next->next) {
 761                 struct commit *commit = next->item;
 762                 *(indegree_slab_at(&indegree, commit)) = 1;
 763                 /* also record the author dates, if needed */
 764                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 765                         record_author_date(&author_date, commit);
 766         }
 767
 768         /* update the indegree */
 769         for (next = orig; next; next = next->next) {
 770                 struct commit_list *parents = next->item->parents;
 771                 while (parents) {
 772                         struct commit *parent = parents->item;
 773                         int *pi = indegree_slab_at(&indegree, parent);
 774
 775                         if (*pi)
 776                                 (*pi)++;
 777                         parents = parents->next;
 778                 }
 779         }
 780
 781         /*
 782          * find the tips
 783          *
 784          * tips are nodes not reachable from any other node in the list
 785          *
 786          * the tips serve as a starting set for the work queue.
 787          */
 788         for (next = orig; next; next = next->next) {
 789                 struct commit *commit = next->item;
 790
 791                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 792                         prio_queue_put(&queue, commit);
 793         }
 794
 795         /*
 796          * This is unfortunate; the initial tips need to be shown
 797          * in the order given from the revision traversal machinery.
 798          */
 799         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 800                 prio_queue_reverse(&queue);
 801
 802         /* We no longer need the commit list */
 803         free_commit_list(orig);
 804
 805         pptr = list;
 806         *list = NULL;
 807         while ((commit = prio_queue_get(&queue)) != NULL) {
 808                 struct commit_list *parents;
 809
 810                 for (parents = commit->parents; parents ; parents = parents->next) {
 811                         struct commit *parent = parents->item;
 812                         int *pi = indegree_slab_at(&indegree, parent);
 813
 814                         if (!*pi)
 815                                 continue;
 816
 817                         /*
 818                          * parents are only enqueued for emission
 819                          * when all their children have been emitted thereby
 820                          * guaranteeing topological order.
 821                          */
 822                         if (--(*pi) == 1)
 823                                 prio_queue_put(&queue, parent);
 824                 }
 825                 /*
 826                  * all children of commit have already been
 827                  * emitted. we can emit it now.
 828                  */
 829                 *(indegree_slab_at(&indegree, commit)) = 0;
 830
 831                 pptr = &commit_list_insert(commit, pptr)->next;
 832         }
 833
 834         clear_indegree_slab(&indegree);
 835         clear_prio_queue(&queue);
 836         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 837                 clear_author_date_slab(&author_date);
 838 }
 839
 840 /* merge-base stuff */
 841
 842 /* Remember to update object flag allocation in object.h */
 843 #define PARENT1         (1u<<16)
 844 #define PARENT2         (1u<<17)
 845 #define STALE           (1u<<18)
 846 #define RESULT          (1u<<19)
 847
 848 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 849
 850 static int queue_has_nonstale(struct prio_queue *queue)
 851 {
 852         int i;
 853         for (i = 0; i < queue->nr; i++) {
 854                 struct commit *commit = queue->array[i].data;
 855                 if (!(commit->object.flags & STALE))
 856                         return 1;
 857         }
 858         return 0;
 859 }
 860
 861 /* all input commits in one and twos[] must have been parsed! */
 862 static struct commit_list *paint_down_to_common(struct commit *one, int n,
 863                                                 struct commit **twos,
 864                                                 int min_generation)
 865 {
 866         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
 867         struct commit_list *result = NULL;
 868         int i;
 869         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
 870
 871         one->object.flags |= PARENT1;
 872         if (!n) {
 873                 commit_list_append(one, &result);
 874                 return result;
 875         }
 876         prio_queue_put(&queue, one);
 877
 878         for (i = 0; i < n; i++) {
 879                 twos[i]->object.flags |= PARENT2;
 880                 prio_queue_put(&queue, twos[i]);
 881         }
 882
 883         while (queue_has_nonstale(&queue)) {
 884                 struct commit *commit = prio_queue_get(&queue);
 885                 struct commit_list *parents;
 886                 int flags;
 887
 888                 if (commit->generation > last_gen)
 889                         BUG("bad generation skip %8x > %8x at %s",
 890                             commit->generation, last_gen,
 891                             oid_to_hex(&commit->object.oid));
 892                 last_gen = commit->generation;
 893
 894                 if (commit->generation < min_generation)
 895                         break;
 896
 897                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 898                 if (flags == (PARENT1 | PARENT2)) {
 899                         if (!(commit->object.flags & RESULT)) {
 900                                 commit->object.flags |= RESULT;
 901                                 commit_list_insert_by_date(commit, &result);
 902                         }
 903                         /* Mark parents of a found merge stale */
 904                         flags |= STALE;
 905                 }
 906                 parents = commit->parents;
 907                 while (parents) {
 908                         struct commit *p = parents->item;
 909                         parents = parents->next;
 910                         if ((p->object.flags & flags) == flags)
 911                                 continue;
 912                         if (parse_commit(p))
 913                                 return NULL;
 914                         p->object.flags |= flags;
 915                         prio_queue_put(&queue, p);
 916                 }
 917         }
 918
 919         clear_prio_queue(&queue);
 920         return result;
 921 }
 922
 923 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 924 {
 925         struct commit_list *list = NULL;
 926         struct commit_list *result = NULL;
 927         int i;
 928
 929         for (i = 0; i < n; i++) {
 930                 if (one == twos[i])
 931                         /*
 932                          * We do not mark this even with RESULT so we do not
 933                          * have to clean it up.
 934                          */
 935                         return commit_list_insert(one, &result);
 936         }
 937
 938         if (parse_commit(one))
 939                 return NULL;
 940         for (i = 0; i < n; i++) {
 941                 if (parse_commit(twos[i]))
 942                         return NULL;
 943         }
 944
 945         list = paint_down_to_common(one, n, twos, 0);
 946
 947         while (list) {
 948                 struct commit *commit = pop_commit(&list);
 949                 if (!(commit->object.flags & STALE))
 950                         commit_list_insert_by_date(commit, &result);
 951         }
 952         return result;
 953 }
 954
 955 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 956 {
 957         struct commit_list *i, *j, *k, *ret = NULL;
 958
 959         if (!in)
 960                 return ret;
 961
 962         commit_list_insert(in->item, &ret);
 963
 964         for (i = in->next; i; i = i->next) {
 965                 struct commit_list *new_commits = NULL, *end = NULL;
 966
 967                 for (j = ret; j; j = j->next) {
 968                         struct commit_list *bases;
 969                         bases = get_merge_bases(i->item, j->item);
 970                         if (!new_commits)
 971                                 new_commits = bases;
 972                         else
 973                                 end->next = bases;
 974                         for (k = bases; k; k = k->next)
 975                                 end = k;
 976                 }
 977                 ret = new_commits;
 978         }
 979         return ret;
 980 }
 981
 982 static int remove_redundant(struct commit **array, int cnt)
 983 {
 984         /*
 985          * Some commit in the array may be an ancestor of
 986          * another commit.  Move such commit to the end of
 987          * the array, and return the number of commits that
 988          * are independent from each other.
 989          */
 990         struct commit **work;
 991         unsigned char *redundant;
 992         int *filled_index;
 993         int i, j, filled;
 994
 995         work = xcalloc(cnt, sizeof(*work));
 996         redundant = xcalloc(cnt, 1);
 997         ALLOC_ARRAY(filled_index, cnt - 1);
 998
 999         for (i = 0; i < cnt; i++)
1000                 parse_commit(array[i]);
1001         for (i = 0; i < cnt; i++) {
1002                 struct commit_list *common;
1003                 uint32_t min_generation = array[i]->generation;
1004
1005                 if (redundant[i])
1006                         continue;
1007                 for (j = filled = 0; j < cnt; j++) {
1008                         if (i == j || redundant[j])
1009                                 continue;
1010                         filled_index[filled] = j;
1011                         work[filled++] = array[j];
1012
1013                         if (array[j]->generation < min_generation)
1014                                 min_generation = array[j]->generation;
1015                 }
1016                 common = paint_down_to_common(array[i], filled, work,
1017                                               min_generation);
1018                 if (array[i]->object.flags & PARENT2)
1019                         redundant[i] = 1;
1020                 for (j = 0; j < filled; j++)
1021                         if (work[j]->object.flags & PARENT1)
1022                                 redundant[filled_index[j]] = 1;
1023                 clear_commit_marks(array[i], all_flags);
1024                 clear_commit_marks_many(filled, work, all_flags);
1025                 free_commit_list(common);
1026         }
1027
1028         /* Now collect the result */
1029         COPY_ARRAY(work, array, cnt);
1030         for (i = filled = 0; i < cnt; i++)
1031                 if (!redundant[i])
1032                         array[filled++] = work[i];
1033         for (j = filled, i = 0; i < cnt; i++)
1034                 if (redundant[i])
1035                         array[j++] = work[i];
1036         free(work);
1037         free(redundant);
1038         free(filled_index);
1039         return filled;
1040 }
1041
1042 static struct commit_list *get_merge_bases_many_0(struct commit *one,
1043                                                   int n,
1044                                                   struct commit **twos,
1045                                                   int cleanup)
1046 {
1047         struct commit_list *list;
1048         struct commit **rslt;
1049         struct commit_list *result;
1050         int cnt, i;
1051
1052         result = merge_bases_many(one, n, twos);
1053         for (i = 0; i < n; i++) {
1054                 if (one == twos[i])
1055                         return result;
1056         }
1057         if (!result || !result->next) {
1058                 if (cleanup) {
1059                         clear_commit_marks(one, all_flags);
1060                         clear_commit_marks_many(n, twos, all_flags);
1061                 }
1062                 return result;
1063         }
1064
1065         /* There are more than one */
1066         cnt = commit_list_count(result);
1067         rslt = xcalloc(cnt, sizeof(*rslt));
1068         for (list = result, i = 0; list; list = list->next)
1069                 rslt[i++] = list->item;
1070         free_commit_list(result);
1071
1072         clear_commit_marks(one, all_flags);
1073         clear_commit_marks_many(n, twos, all_flags);
1074
1075         cnt = remove_redundant(rslt, cnt);
1076         result = NULL;
1077         for (i = 0; i < cnt; i++)
1078                 commit_list_insert_by_date(rslt[i], &result);
1079         free(rslt);
1080         return result;
1081 }
1082
1083 struct commit_list *get_merge_bases_many(struct commit *one,
1084                                          int n,
1085                                          struct commit **twos)
1086 {
1087         return get_merge_bases_many_0(one, n, twos, 1);
1088 }
1089
1090 struct commit_list *get_merge_bases_many_dirty(struct commit *one,
1091                                                int n,
1092                                                struct commit **twos)
1093 {
1094         return get_merge_bases_many_0(one, n, twos, 0);
1095 }
1096
1097 struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
1098 {
1099         return get_merge_bases_many_0(one, 1, &two, 1);
1100 }
1101
1102 /*
1103  * Is "commit" a descendant of one of the elements on the "with_commit" list?
1104  */
1105 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1106 {
1107         if (!with_commit)
1108                 return 1;
1109         while (with_commit) {
1110                 struct commit *other;
1111
1112                 other = with_commit->item;
1113                 with_commit = with_commit->next;
1114                 if (in_merge_bases(other, commit))
1115                         return 1;
1116         }
1117         return 0;
1118 }
1119
1120 /*
1121  * Is "commit" an ancestor of one of the "references"?
1122  */
1123 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1124 {
1125         struct commit_list *bases;
1126         int ret = 0, i;
1127         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
1128
1129         if (parse_commit(commit))
1130                 return ret;
1131         for (i = 0; i < nr_reference; i++) {
1132                 if (parse_commit(reference[i]))
1133                         return ret;
1134                 if (reference[i]->generation < min_generation)
1135                         min_generation = reference[i]->generation;
1136         }
1137
1138         if (commit->generation > min_generation)
1139                 return ret;
1140
1141         bases = paint_down_to_common(commit, nr_reference, reference, commit->generation);
1142         if (commit->object.flags & PARENT2)
1143                 ret = 1;
1144         clear_commit_marks(commit, all_flags);
1145         clear_commit_marks_many(nr_reference, reference, all_flags);
1146         free_commit_list(bases);
1147         return ret;
1148 }
1149
1150 /*
1151  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1152  */
1153 int in_merge_bases(struct commit *commit, struct commit *reference)
1154 {
1155         return in_merge_bases_many(commit, 1, &reference);
1156 }
1157
1158 struct commit_list *reduce_heads(struct commit_list *heads)
1159 {
1160         struct commit_list *p;
1161         struct commit_list *result = NULL, **tail = &result;
1162         struct commit **array;
1163         int num_head, i;
1164
1165         if (!heads)
1166                 return NULL;
1167
1168         /* Uniquify */
1169         for (p = heads; p; p = p->next)
1170                 p->item->object.flags &= ~STALE;
1171         for (p = heads, num_head = 0; p; p = p->next) {
1172                 if (p->item->object.flags & STALE)
1173                         continue;
1174                 p->item->object.flags |= STALE;
1175                 num_head++;
1176         }
1177         array = xcalloc(num_head, sizeof(*array));
1178         for (p = heads, i = 0; p; p = p->next) {
1179                 if (p->item->object.flags & STALE) {
1180                         array[i++] = p->item;
1181                         p->item->object.flags &= ~STALE;
1182                 }
1183         }
1184         num_head = remove_redundant(array, num_head);
1185         for (i = 0; i < num_head; i++)
1186                 tail = &commit_list_insert(array[i], tail)->next;
1187         free(array);
1188         return result;
1189 }
1190
1191 void reduce_heads_replace(struct commit_list **heads)
1192 {
1193         struct commit_list *result = reduce_heads(*heads);
1194         free_commit_list(*heads);
1195         *heads = result;
1196 }
1197
1198 static const char gpg_sig_header[] = "gpgsig";
1199 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1200
1201 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1202 {
1203         struct strbuf sig = STRBUF_INIT;
1204         int inspos, copypos;
1205         const char *eoh;
1206
1207         /* find the end of the header */
1208         eoh = strstr(buf->buf, "\n\n");
1209         if (!eoh)
1210                 inspos = buf->len;
1211         else
1212                 inspos = eoh - buf->buf + 1;
1213
1214         if (!keyid || !*keyid)
1215                 keyid = get_signing_key();
1216         if (sign_buffer(buf, &sig, keyid)) {
1217                 strbuf_release(&sig);
1218                 return -1;
1219         }
1220
1221         for (copypos = 0; sig.buf[copypos]; ) {
1222                 const char *bol = sig.buf + copypos;
1223                 const char *eol = strchrnul(bol, '\n');
1224                 int len = (eol - bol) + !!*eol;
1225
1226                 if (!copypos) {
1227                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1228                         inspos += gpg_sig_header_len;
1229                 }
1230                 strbuf_insert(buf, inspos++, " ", 1);
1231                 strbuf_insert(buf, inspos, bol, len);
1232                 inspos += len;
1233                 copypos += len;
1234         }
1235         strbuf_release(&sig);
1236         return 0;
1237 }
1238
1239 int parse_signed_commit(const struct commit *commit,
1240                         struct strbuf *payload, struct strbuf *signature)
1241 {
1242
1243         unsigned long size;
1244         const char *buffer = get_commit_buffer(commit, &size);
1245         int in_signature, saw_signature = -1;
1246         const char *line, *tail;
1247
1248         line = buffer;
1249         tail = buffer + size;
1250         in_signature = 0;
1251         saw_signature = 0;
1252         while (line < tail) {
1253                 const char *sig = NULL;
1254                 const char *next = memchr(line, '\n', tail - line);
1255
1256                 next = next ? next + 1 : tail;
1257                 if (in_signature && line[0] == ' ')
1258                         sig = line + 1;
1259                 else if (starts_with(line, gpg_sig_header) &&
1260                          line[gpg_sig_header_len] == ' ')
1261                         sig = line + gpg_sig_header_len + 1;
1262                 if (sig) {
1263                         strbuf_add(signature, sig, next - sig);
1264                         saw_signature = 1;
1265                         in_signature = 1;
1266                 } else {
1267                         if (*line == '\n')
1268                                 /* dump the whole remainder of the buffer */
1269                                 next = tail;
1270                         strbuf_add(payload, line, next - line);
1271                         in_signature = 0;
1272                 }
1273                 line = next;
1274         }
1275         unuse_commit_buffer(commit, buffer);
1276         return saw_signature;
1277 }
1278
1279 int remove_signature(struct strbuf *buf)
1280 {
1281         const char *line = buf->buf;
1282         const char *tail = buf->buf + buf->len;
1283         int in_signature = 0;
1284         const char *sig_start = NULL;
1285         const char *sig_end = NULL;
1286
1287         while (line < tail) {
1288                 const char *next = memchr(line, '\n', tail - line);
1289                 next = next ? next + 1 : tail;
1290
1291                 if (in_signature && line[0] == ' ')
1292                         sig_end = next;
1293                 else if (starts_with(line, gpg_sig_header) &&
1294                          line[gpg_sig_header_len] == ' ') {
1295                         sig_start = line;
1296                         sig_end = next;
1297                         in_signature = 1;
1298                 } else {
1299                         if (*line == '\n')
1300                                 /* dump the whole remainder of the buffer */
1301                                 next = tail;
1302                         in_signature = 0;
1303                 }
1304                 line = next;
1305         }
1306
1307         if (sig_start)
1308                 strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1309
1310         return sig_start != NULL;
1311 }
1312
1313 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1314 {
1315         struct merge_remote_desc *desc;
1316         struct commit_extra_header *mergetag;
1317         char *buf;
1318         unsigned long size, len;
1319         enum object_type type;
1320
1321         desc = merge_remote_util(parent);
1322         if (!desc || !desc->obj)
1323                 return;
1324         buf = read_object_file(&desc->obj->oid, &type, &size);
1325         if (!buf || type != OBJ_TAG)
1326                 goto free_return;
1327         len = parse_signature(buf, size);
1328         if (size == len)
1329                 goto free_return;
1330         /*
1331          * We could verify this signature and either omit the tag when
1332          * it does not validate, but the integrator may not have the
1333          * public key of the signer of the tag he is merging, while a
1334          * later auditor may have it while auditing, so let's not run
1335          * verify-signed-buffer here for now...
1336          *
1337          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1338          *      warn("warning: signed tag unverified.");
1339          */
1340         mergetag = xcalloc(1, sizeof(*mergetag));
1341         mergetag->key = xstrdup("mergetag");
1342         mergetag->value = buf;
1343         mergetag->len = size;
1344
1345         **tail = mergetag;
1346         *tail = &mergetag->next;
1347         return;
1348
1349 free_return:
1350         free(buf);
1351 }
1352
1353 int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1354 {
1355         struct strbuf payload = STRBUF_INIT;
1356         struct strbuf signature = STRBUF_INIT;
1357         int ret = 1;
1358
1359         sigc->result = 'N';
1360
1361         if (parse_signed_commit(commit, &payload, &signature) <= 0)
1362                 goto out;
1363         ret = check_signature(payload.buf, payload.len, signature.buf,
1364                 signature.len, sigc);
1365
1366  out:
1367         strbuf_release(&payload);
1368         strbuf_release(&signature);
1369
1370         return ret;
1371 }
1372
1373
1374
1375 void append_merge_tag_headers(struct commit_list *parents,
1376                               struct commit_extra_header ***tail)
1377 {
1378         while (parents) {
1379                 struct commit *parent = parents->item;
1380                 handle_signed_tag(parent, tail);
1381                 parents = parents->next;
1382         }
1383 }
1384
1385 static void add_extra_header(struct strbuf *buffer,
1386                              struct commit_extra_header *extra)
1387 {
1388         strbuf_addstr(buffer, extra->key);
1389         if (extra->len)
1390                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1391         else
1392                 strbuf_addch(buffer, '\n');
1393 }
1394
1395 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1396                                                       const char **exclude)
1397 {
1398         struct commit_extra_header *extra = NULL;
1399         unsigned long size;
1400         const char *buffer = get_commit_buffer(commit, &size);
1401         extra = read_commit_extra_header_lines(buffer, size, exclude);
1402         unuse_commit_buffer(commit, buffer);
1403         return extra;
1404 }
1405
1406 int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1407 {
1408         struct commit_extra_header *extra, *to_free;
1409         int res = 0;
1410
1411         to_free = read_commit_extra_headers(commit, NULL);
1412         for (extra = to_free; !res && extra; extra = extra->next) {
1413                 if (strcmp(extra->key, "mergetag"))
1414                         continue; /* not a merge tag */
1415                 res = fn(commit, extra, data);
1416         }
1417         free_commit_extra_headers(to_free);
1418         return res;
1419 }
1420
1421 static inline int standard_header_field(const char *field, size_t len)
1422 {
1423         return ((len == 4 && !memcmp(field, "tree", 4)) ||
1424                 (len == 6 && !memcmp(field, "parent", 6)) ||
1425                 (len == 6 && !memcmp(field, "author", 6)) ||
1426                 (len == 9 && !memcmp(field, "committer", 9)) ||
1427                 (len == 8 && !memcmp(field, "encoding", 8)));
1428 }
1429
1430 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1431 {
1432         if (!exclude)
1433                 return 0;
1434
1435         while (*exclude) {
1436                 size_t xlen = strlen(*exclude);
1437                 if (len == xlen && !memcmp(field, *exclude, xlen))
1438                         return 1;
1439                 exclude++;
1440         }
1441         return 0;
1442 }
1443
1444 static struct commit_extra_header *read_commit_extra_header_lines(
1445         const char *buffer, size_t size,
1446         const char **exclude)
1447 {
1448         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1449         const char *line, *next, *eof, *eob;
1450         struct strbuf buf = STRBUF_INIT;
1451
1452         for (line = buffer, eob = line + size;
1453              line < eob && *line != '\n';
1454              line = next) {
1455                 next = memchr(line, '\n', eob - line);
1456                 next = next ? next + 1 : eob;
1457                 if (*line == ' ') {
1458                         /* continuation */
1459                         if (it)
1460                                 strbuf_add(&buf, line + 1, next - (line + 1));
1461                         continue;
1462                 }
1463                 if (it)
1464                         it->value = strbuf_detach(&buf, &it->len);
1465                 strbuf_reset(&buf);
1466                 it = NULL;
1467
1468                 eof = memchr(line, ' ', next - line);
1469                 if (!eof)
1470                         eof = next;
1471                 else if (standard_header_field(line, eof - line) ||
1472                          excluded_header_field(line, eof - line, exclude))
1473                         continue;
1474
1475                 it = xcalloc(1, sizeof(*it));
1476                 it->key = xmemdupz(line, eof-line);
1477                 *tail = it;
1478                 tail = &it->next;
1479                 if (eof + 1 < next)
1480                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1481         }
1482         if (it)
1483                 it->value = strbuf_detach(&buf, &it->len);
1484         return extra;
1485 }
1486
1487 void free_commit_extra_headers(struct commit_extra_header *extra)
1488 {
1489         while (extra) {
1490                 struct commit_extra_header *next = extra->next;
1491                 free(extra->key);
1492                 free(extra->value);
1493                 free(extra);
1494                 extra = next;
1495         }
1496 }
1497
1498 int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
1499                 struct commit_list *parents, struct object_id *ret,
1500                 const char *author, const char *sign_commit)
1501 {
1502         struct commit_extra_header *extra = NULL, **tail = &extra;
1503         int result;
1504
1505         append_merge_tag_headers(parents, &tail);
1506         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1507                                       author, sign_commit, extra);
1508         free_commit_extra_headers(extra);
1509         return result;
1510 }
1511
1512 static int find_invalid_utf8(const char *buf, int len)
1513 {
1514         int offset = 0;
1515         static const unsigned int max_codepoint[] = {
1516                 0x7f, 0x7ff, 0xffff, 0x10ffff
1517         };
1518
1519         while (len) {
1520                 unsigned char c = *buf++;
1521                 int bytes, bad_offset;
1522                 unsigned int codepoint;
1523                 unsigned int min_val, max_val;
1524
1525                 len--;
1526                 offset++;
1527
1528                 /* Simple US-ASCII? No worries. */
1529                 if (c < 0x80)
1530                         continue;
1531
1532                 bad_offset = offset-1;
1533
1534                 /*
1535                  * Count how many more high bits set: that's how
1536                  * many more bytes this sequence should have.
1537                  */
1538                 bytes = 0;
1539                 while (c & 0x40) {
1540                         c <<= 1;
1541                         bytes++;
1542                 }
1543
1544                 /*
1545                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1546                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1547                  */
1548                 if (bytes < 1 || 3 < bytes)
1549                         return bad_offset;
1550
1551                 /* Do we *have* that many bytes? */
1552                 if (len < bytes)
1553                         return bad_offset;
1554
1555                 /*
1556                  * Place the encoded bits at the bottom of the value and compute the
1557                  * valid range.
1558                  */
1559                 codepoint = (c & 0x7f) >> bytes;
1560                 min_val = max_codepoint[bytes-1] + 1;
1561                 max_val = max_codepoint[bytes];
1562
1563                 offset += bytes;
1564                 len -= bytes;
1565
1566                 /* And verify that they are good continuation bytes */
1567                 do {
1568                         codepoint <<= 6;
1569                         codepoint |= *buf & 0x3f;
1570                         if ((*buf++ & 0xc0) != 0x80)
1571                                 return bad_offset;
1572                 } while (--bytes);
1573
1574                 /* Reject codepoints that are out of range for the sequence length. */
1575                 if (codepoint < min_val || codepoint > max_val)
1576                         return bad_offset;
1577                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1578                 if ((codepoint & 0x1ff800) == 0xd800)
1579                         return bad_offset;
1580                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1581                 if ((codepoint & 0xfffe) == 0xfffe)
1582                         return bad_offset;
1583                 /* So are anything in the range U+FDD0..U+FDEF. */
1584                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1585                         return bad_offset;
1586         }
1587         return -1;
1588 }
1589
1590 /*
1591  * This verifies that the buffer is in proper utf8 format.
1592  *
1593  * If it isn't, it assumes any non-utf8 characters are Latin1,
1594  * and does the conversion.
1595  */
1596 static int verify_utf8(struct strbuf *buf)
1597 {
1598         int ok = 1;
1599         long pos = 0;
1600
1601         for (;;) {
1602                 int bad;
1603                 unsigned char c;
1604                 unsigned char replace[2];
1605
1606                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1607                 if (bad < 0)
1608                         return ok;
1609                 pos += bad;
1610                 ok = 0;
1611                 c = buf->buf[pos];
1612                 strbuf_remove(buf, pos, 1);
1613
1614                 /* We know 'c' must be in the range 128-255 */
1615                 replace[0] = 0xc0 + (c >> 6);
1616                 replace[1] = 0x80 + (c & 0x3f);
1617                 strbuf_insert(buf, pos, replace, 2);
1618                 pos += 2;
1619         }
1620 }
1621
1622 static const char commit_utf8_warn[] =
1623 N_("Warning: commit message did not conform to UTF-8.\n"
1624    "You may want to amend it after fixing the message, or set the config\n"
1625    "variable i18n.commitencoding to the encoding your project uses.\n");
1626
1627 int commit_tree_extended(const char *msg, size_t msg_len,
1628                          const struct object_id *tree,
1629                          struct commit_list *parents, struct object_id *ret,
1630                          const char *author, const char *sign_commit,
1631                          struct commit_extra_header *extra)
1632 {
1633         int result;
1634         int encoding_is_utf8;
1635         struct strbuf buffer;
1636
1637         assert_oid_type(tree, OBJ_TREE);
1638
1639         if (memchr(msg, '\0', msg_len))
1640                 return error("a NUL byte in commit log message not allowed.");
1641
1642         /* Not having i18n.commitencoding is the same as having utf-8 */
1643         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1644
1645         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1646         strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
1647
1648         /*
1649          * NOTE! This ordering means that the same exact tree merged with a
1650          * different order of parents will be a _different_ changeset even
1651          * if everything else stays the same.
1652          */
1653         while (parents) {
1654                 struct commit *parent = pop_commit(&parents);
1655                 strbuf_addf(&buffer, "parent %s\n",
1656                             oid_to_hex(&parent->object.oid));
1657         }
1658
1659         /* Person/date information */
1660         if (!author)
1661                 author = git_author_info(IDENT_STRICT);
1662         strbuf_addf(&buffer, "author %s\n", author);
1663         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1664         if (!encoding_is_utf8)
1665                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1666
1667         while (extra) {
1668                 add_extra_header(&buffer, extra);
1669                 extra = extra->next;
1670         }
1671         strbuf_addch(&buffer, '\n');
1672
1673         /* And add the comment */
1674         strbuf_add(&buffer, msg, msg_len);
1675
1676         /* And check the encoding */
1677         if (encoding_is_utf8 && !verify_utf8(&buffer))
1678                 fprintf(stderr, _(commit_utf8_warn));
1679
1680         if (sign_commit && do_sign_commit(&buffer, sign_commit)) {
1681                 result = -1;
1682                 goto out;
1683         }
1684
1685         result = write_object_file(buffer.buf, buffer.len, commit_type, ret);
1686 out:
1687         strbuf_release(&buffer);
1688         return result;
1689 }
1690
1691 define_commit_slab(merge_desc_slab, struct merge_remote_desc *);
1692 static struct merge_desc_slab merge_desc_slab = COMMIT_SLAB_INIT(1, merge_desc_slab);
1693
1694 struct merge_remote_desc *merge_remote_util(struct commit *commit)
1695 {
1696         return *merge_desc_slab_at(&merge_desc_slab, commit);
1697 }
1698
1699 void set_merge_remote_desc(struct commit *commit,
1700                            const char *name, struct object *obj)
1701 {
1702         struct merge_remote_desc *desc;
1703         FLEX_ALLOC_STR(desc, name, name);
1704         desc->obj = obj;
1705         *merge_desc_slab_at(&merge_desc_slab, commit) = desc;
1706 }
1707
1708 struct commit *get_merge_parent(const char *name)
1709 {
1710         struct object *obj;
1711         struct commit *commit;
1712         struct object_id oid;
1713         if (get_oid(name, &oid))
1714                 return NULL;
1715         obj = parse_object(the_repository, &oid);
1716         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1717         if (commit && !merge_remote_util(commit))
1718                 set_merge_remote_desc(commit, name, obj);
1719         return commit;
1720 }
1721
1722 /*
1723  * Append a commit to the end of the commit_list.
1724  *
1725  * next starts by pointing to the variable that holds the head of an
1726  * empty commit_list, and is updated to point to the "next" field of
1727  * the last item on the list as new commits are appended.
1728  *
1729  * Usage example:
1730  *
1731  *     struct commit_list *list;
1732  *     struct commit_list **next = &list;
1733  *
1734  *     next = commit_list_append(c1, next);
1735  *     next = commit_list_append(c2, next);
1736  *     assert(commit_list_count(list) == 2);
1737  *     return list;
1738  */
1739 struct commit_list **commit_list_append(struct commit *commit,
1740                                         struct commit_list **next)
1741 {
1742         struct commit_list *new_commit = xmalloc(sizeof(struct commit_list));
1743         new_commit->item = commit;
1744         *next = new_commit;
1745         new_commit->next = NULL;
1746         return &new_commit->next;
1747 }
1748
1749 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1750 {
1751         int key_len = strlen(key);
1752         const char *line = msg;
1753
1754         while (line) {
1755                 const char *eol = strchrnul(line, '\n');
1756
1757                 if (line == eol)
1758                         return NULL;
1759
1760                 if (eol - line > key_len &&
1761                     !strncmp(line, key, key_len) &&
1762                     line[key_len] == ' ') {
1763                         *out_len = eol - line - key_len - 1;
1764                         return line + key_len + 1;
1765                 }
1766                 line = *eol ? eol + 1 : NULL;
1767         }
1768         return NULL;
1769 }
1770
1771 /*
1772  * Inspect the given string and determine the true "end" of the log message, in
1773  * order to find where to put a new Signed-off-by: line.  Ignored are
1774  * trailing comment lines and blank lines.  To support "git commit -s
1775  * --amend" on an existing commit, we also ignore "Conflicts:".  To
1776  * support "git commit -v", we truncate at cut lines.
1777  *
1778  * Returns the number of bytes from the tail to ignore, to be fed as
1779  * the second parameter to append_signoff().
1780  */
1781 int ignore_non_trailer(const char *buf, size_t len)
1782 {
1783         int boc = 0;
1784         int bol = 0;
1785         int in_old_conflicts_block = 0;
1786         size_t cutoff = wt_status_locate_end(buf, len);
1787
1788         while (bol < cutoff) {
1789                 const char *next_line = memchr(buf + bol, '\n', len - bol);
1790
1791                 if (!next_line)
1792                         next_line = buf + len;
1793                 else
1794                         next_line++;
1795
1796                 if (buf[bol] == comment_line_char || buf[bol] == '\n') {
1797                         /* is this the first of the run of comments? */
1798                         if (!boc)
1799                                 boc = bol;
1800                         /* otherwise, it is just continuing */
1801                 } else if (starts_with(buf + bol, "Conflicts:\n")) {
1802                         in_old_conflicts_block = 1;
1803                         if (!boc)
1804                                 boc = bol;
1805                 } else if (in_old_conflicts_block && buf[bol] == '\t') {
1806                         ; /* a pathname in the conflicts block */
1807                 } else if (boc) {
1808                         /* the previous was not trailing comment */
1809                         boc = 0;
1810                         in_old_conflicts_block = 0;
1811                 }
1812                 bol = next_line - buf;
1813         }
1814         return boc ? len - boc : len - cutoff;
1815 }