commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "commit-graph.h"
   5 #include "gettext.h"
   6 #include "hex.h"
   7 #include "repository.h"
   8 #include "object-store.h"
   9 #include "pkt-line.h"
  10 #include "utf8.h"
  11 #include "diff.h"
  12 #include "revision.h"
  13 #include "notes.h"
  14 #include "alloc.h"
  15 #include "gpg-interface.h"
  16 #include "mergesort.h"
  17 #include "commit-slab.h"
  18 #include "prio-queue.h"
  19 #include "hash-lookup.h"
  20 #include "wt-status.h"
  21 #include "advice.h"
  22 #include "refs.h"
  23 #include "commit-reach.h"
  24 #include "run-command.h"
  25 #include "shallow.h"
  26 #include "hook.h"
  27
  28 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  29
  30 int save_commit_buffer = 1;
  31 int no_graft_file_deprecated_advice;
  32
  33 const char *commit_type = "commit";
  34
  35 struct commit *lookup_commit_reference_gently(struct repository *r,
  36                 const struct object_id *oid, int quiet)
  37 {
  38         struct object *obj = deref_tag(r,
  39                                        parse_object(r, oid),
  40                                        NULL, 0);
  41
  42         if (!obj)
  43                 return NULL;
  44         return object_as_type(obj, OBJ_COMMIT, quiet);
  45 }
  46
  47 struct commit *lookup_commit_reference(struct repository *r, const struct object_id *oid)
  48 {
  49         return lookup_commit_reference_gently(r, oid, 0);
  50 }
  51
  52 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
  53 {
  54         struct commit *c = lookup_commit_reference(the_repository, oid);
  55         if (!c)
  56                 die(_("could not parse %s"), ref_name);
  57         if (!oideq(oid, &c->object.oid)) {
  58                 warning(_("%s %s is not a commit!"),
  59                         ref_name, oid_to_hex(oid));
  60         }
  61         return c;
  62 }
  63
  64 struct commit *lookup_commit_object(struct repository *r,
  65                                     const struct object_id *oid)
  66 {
  67         struct object *obj = parse_object(r, oid);
  68         return obj ? object_as_type(obj, OBJ_COMMIT, 0) : NULL;
  69
  70 }
  71
  72 struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
  73 {
  74         struct object *obj = lookup_object(r, oid);
  75         if (!obj)
  76                 return create_object(r, oid, alloc_commit_node(r));
  77         return object_as_type(obj, OBJ_COMMIT, 0);
  78 }
  79
  80 struct commit *lookup_commit_reference_by_name(const char *name)
  81 {
  82         struct object_id oid;
  83         struct commit *commit;
  84
  85         if (get_oid_committish(name, &oid))
  86                 return NULL;
  87         commit = lookup_commit_reference(the_repository, &oid);
  88         if (parse_commit(commit))
  89                 return NULL;
  90         return commit;
  91 }
  92
  93 static timestamp_t parse_commit_date(const char *buf, const char *tail)
  94 {
  95         const char *dateptr;
  96
  97         if (buf + 6 >= tail)
  98                 return 0;
  99         if (memcmp(buf, "author", 6))
 100                 return 0;
 101         while (buf < tail && *buf++ != '\n')
 102                 /* nada */;
 103         if (buf + 9 >= tail)
 104                 return 0;
 105         if (memcmp(buf, "committer", 9))
 106                 return 0;
 107         while (buf < tail && *buf++ != '>')
 108                 /* nada */;
 109         if (buf >= tail)
 110                 return 0;
 111         dateptr = buf;
 112         while (buf < tail && *buf++ != '\n')
 113                 /* nada */;
 114         if (buf >= tail)
 115                 return 0;
 116         /* dateptr < buf && buf[-1] == '\n', so parsing will stop at buf-1 */
 117         return parse_timestamp(dateptr, NULL, 10);
 118 }
 119
 120 static const struct object_id *commit_graft_oid_access(size_t index, const void *table)
 121 {
 122         const struct commit_graft * const *commit_graft_table = table;
 123         return &commit_graft_table[index]->oid;
 124 }
 125
 126 int commit_graft_pos(struct repository *r, const struct object_id *oid)
 127 {
 128         return oid_pos(oid, r->parsed_objects->grafts,
 129                        r->parsed_objects->grafts_nr,
 130                        commit_graft_oid_access);
 131 }
 132
 133 static void unparse_commit(struct repository *r, const struct object_id *oid)
 134 {
 135         struct commit *c = lookup_commit(r, oid);
 136
 137         if (!c->object.parsed)
 138                 return;
 139         free_commit_list(c->parents);
 140         c->parents = NULL;
 141         c->object.parsed = 0;
 142 }
 143
 144 int register_commit_graft(struct repository *r, struct commit_graft *graft,
 145                           int ignore_dups)
 146 {
 147         int pos = commit_graft_pos(r, &graft->oid);
 148
 149         if (0 <= pos) {
 150                 if (ignore_dups)
 151                         free(graft);
 152                 else {
 153                         free(r->parsed_objects->grafts[pos]);
 154                         r->parsed_objects->grafts[pos] = graft;
 155                 }
 156                 return 1;
 157         }
 158         pos = -pos - 1;
 159         ALLOC_GROW(r->parsed_objects->grafts,
 160                    r->parsed_objects->grafts_nr + 1,
 161                    r->parsed_objects->grafts_alloc);
 162         r->parsed_objects->grafts_nr++;
 163         if (pos < r->parsed_objects->grafts_nr)
 164                 memmove(r->parsed_objects->grafts + pos + 1,
 165                         r->parsed_objects->grafts + pos,
 166                         (r->parsed_objects->grafts_nr - pos - 1) *
 167                         sizeof(*r->parsed_objects->grafts));
 168         r->parsed_objects->grafts[pos] = graft;
 169         unparse_commit(r, &graft->oid);
 170         return 0;
 171 }
 172
 173 struct commit_graft *read_graft_line(struct strbuf *line)
 174 {
 175         /* The format is just "Commit Parent1 Parent2 ...\n" */
 176         int i, phase;
 177         const char *tail = NULL;
 178         struct commit_graft *graft = NULL;
 179         struct object_id dummy_oid, *oid;
 180
 181         strbuf_rtrim(line);
 182         if (!line->len || line->buf[0] == '#')
 183                 return NULL;
 184         /*
 185          * phase 0 verifies line, counts hashes in line and allocates graft
 186          * phase 1 fills graft
 187          */
 188         for (phase = 0; phase < 2; phase++) {
 189                 oid = graft ? &graft->oid : &dummy_oid;
 190                 if (parse_oid_hex(line->buf, oid, &tail))
 191                         goto bad_graft_data;
 192                 for (i = 0; *tail != '\0'; i++) {
 193                         oid = graft ? &graft->parent[i] : &dummy_oid;
 194                         if (!isspace(*tail++) || parse_oid_hex(tail, oid, &tail))
 195                                 goto bad_graft_data;
 196                 }
 197                 if (!graft) {
 198                         graft = xmalloc(st_add(sizeof(*graft),
 199                                                st_mult(sizeof(struct object_id), i)));
 200                         graft->nr_parent = i;
 201                 }
 202         }
 203         return graft;
 204
 205 bad_graft_data:
 206         error("bad graft data: %s", line->buf);
 207         assert(!graft);
 208         return NULL;
 209 }
 210
 211 static int read_graft_file(struct repository *r, const char *graft_file)
 212 {
 213         FILE *fp = fopen_or_warn(graft_file, "r");
 214         struct strbuf buf = STRBUF_INIT;
 215         if (!fp)
 216                 return -1;
 217         if (!no_graft_file_deprecated_advice &&
 218             advice_enabled(ADVICE_GRAFT_FILE_DEPRECATED))
 219                 advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
 220                          "and will be removed in a future Git version.\n"
 221                          "\n"
 222                          "Please use \"git replace --convert-graft-file\"\n"
 223                          "to convert the grafts into replace refs.\n"
 224                          "\n"
 225                          "Turn this message off by running\n"
 226                          "\"git config advice.graftFileDeprecated false\""));
 227         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 228                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 229                 struct commit_graft *graft = read_graft_line(&buf);
 230                 if (!graft)
 231                         continue;
 232                 if (register_commit_graft(r, graft, 1))
 233                         error("duplicate graft data: %s", buf.buf);
 234         }
 235         fclose(fp);
 236         strbuf_release(&buf);
 237         return 0;
 238 }
 239
 240 void prepare_commit_graft(struct repository *r)
 241 {
 242         char *graft_file;
 243
 244         if (r->parsed_objects->commit_graft_prepared)
 245                 return;
 246         if (!startup_info->have_repository)
 247                 return;
 248
 249         graft_file = get_graft_file(r);
 250         read_graft_file(r, graft_file);
 251         /* make sure shallows are read */
 252         is_repository_shallow(r);
 253         r->parsed_objects->commit_graft_prepared = 1;
 254 }
 255
 256 struct commit_graft *lookup_commit_graft(struct repository *r, const struct object_id *oid)
 257 {
 258         int pos;
 259         prepare_commit_graft(r);
 260         pos = commit_graft_pos(r, oid);
 261         if (pos < 0)
 262                 return NULL;
 263         return r->parsed_objects->grafts[pos];
 264 }
 265
 266 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 267 {
 268         int i, ret;
 269         for (i = ret = 0; i < the_repository->parsed_objects->grafts_nr && !ret; i++)
 270                 ret = fn(the_repository->parsed_objects->grafts[i], cb_data);
 271         return ret;
 272 }
 273
 274 void reset_commit_grafts(struct repository *r)
 275 {
 276         int i;
 277
 278         for (i = 0; i < r->parsed_objects->grafts_nr; i++) {
 279                 unparse_commit(r, &r->parsed_objects->grafts[i]->oid);
 280                 free(r->parsed_objects->grafts[i]);
 281         }
 282         r->parsed_objects->grafts_nr = 0;
 283         r->parsed_objects->commit_graft_prepared = 0;
 284 }
 285
 286 struct commit_buffer {
 287         void *buffer;
 288         unsigned long size;
 289 };
 290 define_commit_slab(buffer_slab, struct commit_buffer);
 291
 292 struct buffer_slab *allocate_commit_buffer_slab(void)
 293 {
 294         struct buffer_slab *bs = xmalloc(sizeof(*bs));
 295         init_buffer_slab(bs);
 296         return bs;
 297 }
 298
 299 void free_commit_buffer_slab(struct buffer_slab *bs)
 300 {
 301         clear_buffer_slab(bs);
 302         free(bs);
 303 }
 304
 305 void set_commit_buffer(struct repository *r, struct commit *commit, void *buffer, unsigned long size)
 306 {
 307         struct commit_buffer *v = buffer_slab_at(
 308                 r->parsed_objects->buffer_slab, commit);
 309         v->buffer = buffer;
 310         v->size = size;
 311 }
 312
 313 const void *get_cached_commit_buffer(struct repository *r, const struct commit *commit, unsigned long *sizep)
 314 {
 315         struct commit_buffer *v = buffer_slab_peek(
 316                 r->parsed_objects->buffer_slab, commit);
 317         if (!v) {
 318                 if (sizep)
 319                         *sizep = 0;
 320                 return NULL;
 321         }
 322         if (sizep)
 323                 *sizep = v->size;
 324         return v->buffer;
 325 }
 326
 327 const void *repo_get_commit_buffer(struct repository *r,
 328                                    const struct commit *commit,
 329                                    unsigned long *sizep)
 330 {
 331         const void *ret = get_cached_commit_buffer(r, commit, sizep);
 332         if (!ret) {
 333                 enum object_type type;
 334                 unsigned long size;
 335                 ret = repo_read_object_file(r, &commit->object.oid, &type, &size);
 336                 if (!ret)
 337                         die("cannot read commit object %s",
 338                             oid_to_hex(&commit->object.oid));
 339                 if (type != OBJ_COMMIT)
 340                         die("expected commit for %s, got %s",
 341                             oid_to_hex(&commit->object.oid), type_name(type));
 342                 if (sizep)
 343                         *sizep = size;
 344         }
 345         return ret;
 346 }
 347
 348 void repo_unuse_commit_buffer(struct repository *r,
 349                               const struct commit *commit,
 350                               const void *buffer)
 351 {
 352         struct commit_buffer *v = buffer_slab_peek(
 353                 r->parsed_objects->buffer_slab, commit);
 354         if (!(v && v->buffer == buffer))
 355                 free((void *)buffer);
 356 }
 357
 358 void free_commit_buffer(struct parsed_object_pool *pool, struct commit *commit)
 359 {
 360         struct commit_buffer *v = buffer_slab_peek(
 361                 pool->buffer_slab, commit);
 362         if (v) {
 363                 FREE_AND_NULL(v->buffer);
 364                 v->size = 0;
 365         }
 366 }
 367
 368 static inline void set_commit_tree(struct commit *c, struct tree *t)
 369 {
 370         c->maybe_tree = t;
 371 }
 372
 373 struct tree *repo_get_commit_tree(struct repository *r,
 374                                   const struct commit *commit)
 375 {
 376         if (commit->maybe_tree || !commit->object.parsed)
 377                 return commit->maybe_tree;
 378
 379         if (commit_graph_position(commit) != COMMIT_NOT_FROM_GRAPH)
 380                 return get_commit_tree_in_graph(r, commit);
 381
 382         return NULL;
 383 }
 384
 385 struct object_id *get_commit_tree_oid(const struct commit *commit)
 386 {
 387         struct tree *tree = get_commit_tree(commit);
 388         return tree ? &tree->object.oid : NULL;
 389 }
 390
 391 void release_commit_memory(struct parsed_object_pool *pool, struct commit *c)
 392 {
 393         set_commit_tree(c, NULL);
 394         free_commit_buffer(pool, c);
 395         c->index = 0;
 396         free_commit_list(c->parents);
 397
 398         c->object.parsed = 0;
 399 }
 400
 401 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 402 {
 403         struct commit_buffer *v = buffer_slab_peek(
 404                 the_repository->parsed_objects->buffer_slab, commit);
 405         void *ret;
 406
 407         if (!v) {
 408                 if (sizep)
 409                         *sizep = 0;
 410                 return NULL;
 411         }
 412         ret = v->buffer;
 413         if (sizep)
 414                 *sizep = v->size;
 415
 416         v->buffer = NULL;
 417         v->size = 0;
 418         return ret;
 419 }
 420
 421 int parse_commit_buffer(struct repository *r, struct commit *item, const void *buffer, unsigned long size, int check_graph)
 422 {
 423         const char *tail = buffer;
 424         const char *bufptr = buffer;
 425         struct object_id parent;
 426         struct commit_list **pptr;
 427         struct commit_graft *graft;
 428         const int tree_entry_len = the_hash_algo->hexsz + 5;
 429         const int parent_entry_len = the_hash_algo->hexsz + 7;
 430         struct tree *tree;
 431
 432         if (item->object.parsed)
 433                 return 0;
 434         /*
 435          * Presumably this is leftover from an earlier failed parse;
 436          * clear it out in preparation for us re-parsing (we'll hit the
 437          * same error, but that's good, since it lets our caller know
 438          * the result cannot be trusted.
 439          */
 440         free_commit_list(item->parents);
 441         item->parents = NULL;
 442
 443         tail += size;
 444         if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 445                         bufptr[tree_entry_len] != '\n')
 446                 return error("bogus commit object %s", oid_to_hex(&item->object.oid));
 447         if (get_oid_hex(bufptr + 5, &parent) < 0)
 448                 return error("bad tree pointer in commit %s",
 449                              oid_to_hex(&item->object.oid));
 450         tree = lookup_tree(r, &parent);
 451         if (!tree)
 452                 return error("bad tree pointer %s in commit %s",
 453                              oid_to_hex(&parent),
 454                              oid_to_hex(&item->object.oid));
 455         set_commit_tree(item, tree);
 456         bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 457         pptr = &item->parents;
 458
 459         graft = lookup_commit_graft(r, &item->object.oid);
 460         if (graft)
 461                 r->parsed_objects->substituted_parent = 1;
 462         while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 463                 struct commit *new_parent;
 464
 465                 if (tail <= bufptr + parent_entry_len + 1 ||
 466                     get_oid_hex(bufptr + 7, &parent) ||
 467                     bufptr[parent_entry_len] != '\n')
 468                         return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
 469                 bufptr += parent_entry_len + 1;
 470                 /*
 471                  * The clone is shallow if nr_parent < 0, and we must
 472                  * not traverse its real parents even when we unhide them.
 473                  */
 474                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 475                         continue;
 476                 new_parent = lookup_commit(r, &parent);
 477                 if (!new_parent)
 478                         return error("bad parent %s in commit %s",
 479                                      oid_to_hex(&parent),
 480                                      oid_to_hex(&item->object.oid));
 481                 pptr = &commit_list_insert(new_parent, pptr)->next;
 482         }
 483         if (graft) {
 484                 int i;
 485                 struct commit *new_parent;
 486                 for (i = 0; i < graft->nr_parent; i++) {
 487                         new_parent = lookup_commit(r,
 488                                                    &graft->parent[i]);
 489                         if (!new_parent)
 490                                 return error("bad graft parent %s in commit %s",
 491                                              oid_to_hex(&graft->parent[i]),
 492                                              oid_to_hex(&item->object.oid));
 493                         pptr = &commit_list_insert(new_parent, pptr)->next;
 494                 }
 495         }
 496         item->date = parse_commit_date(bufptr, tail);
 497
 498         if (check_graph)
 499                 load_commit_graph_info(r, item);
 500
 501         item->object.parsed = 1;
 502         return 0;
 503 }
 504
 505 int repo_parse_commit_internal(struct repository *r,
 506                                struct commit *item,
 507                                int quiet_on_missing,
 508                                int use_commit_graph)
 509 {
 510         enum object_type type;
 511         void *buffer;
 512         unsigned long size;
 513         struct object_info oi = {
 514                 .typep = &type,
 515                 .sizep = &size,
 516                 .contentp = &buffer,
 517         };
 518         /*
 519          * Git does not support partial clones that exclude commits, so set
 520          * OBJECT_INFO_SKIP_FETCH_OBJECT to fail fast when an object is missing.
 521          */
 522         int flags = OBJECT_INFO_LOOKUP_REPLACE | OBJECT_INFO_SKIP_FETCH_OBJECT |
 523                 OBJECT_INFO_DIE_IF_CORRUPT;
 524         int ret;
 525
 526         if (!item)
 527                 return -1;
 528         if (item->object.parsed)
 529                 return 0;
 530         if (use_commit_graph && parse_commit_in_graph(r, item))
 531                 return 0;
 532
 533         if (oid_object_info_extended(r, &item->object.oid, &oi, flags) < 0)
 534                 return quiet_on_missing ? -1 :
 535                         error("Could not read %s",
 536                              oid_to_hex(&item->object.oid));
 537         if (type != OBJ_COMMIT) {
 538                 free(buffer);
 539                 return error("Object %s not a commit",
 540                              oid_to_hex(&item->object.oid));
 541         }
 542
 543         ret = parse_commit_buffer(r, item, buffer, size, 0);
 544         if (save_commit_buffer && !ret) {
 545                 set_commit_buffer(r, item, buffer, size);
 546                 return 0;
 547         }
 548         free(buffer);
 549         return ret;
 550 }
 551
 552 int repo_parse_commit_gently(struct repository *r,
 553                              struct commit *item, int quiet_on_missing)
 554 {
 555         return repo_parse_commit_internal(r, item, quiet_on_missing, 1);
 556 }
 557
 558 void parse_commit_or_die(struct commit *item)
 559 {
 560         if (parse_commit(item))
 561                 die("unable to parse commit %s",
 562                     item ? oid_to_hex(&item->object.oid) : "(null)");
 563 }
 564
 565 int find_commit_subject(const char *commit_buffer, const char **subject)
 566 {
 567         const char *eol;
 568         const char *p = commit_buffer;
 569
 570         while (*p && (*p != '\n' || p[1] != '\n'))
 571                 p++;
 572         if (*p) {
 573                 p = skip_blank_lines(p + 2);
 574                 eol = strchrnul(p, '\n');
 575         } else
 576                 eol = p;
 577
 578         *subject = p;
 579
 580         return eol - p;
 581 }
 582
 583 size_t commit_subject_length(const char *body)
 584 {
 585         const char *p = body;
 586         while (*p) {
 587                 const char *next = skip_blank_lines(p);
 588                 if (next != p)
 589                         break;
 590                 p = strchrnul(p, '\n');
 591                 if (*p)
 592                         p++;
 593         }
 594         return p - body;
 595 }
 596
 597 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 598 {
 599         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 600         new_list->item = item;
 601         new_list->next = *list_p;
 602         *list_p = new_list;
 603         return new_list;
 604 }
 605
 606 int commit_list_contains(struct commit *item, struct commit_list *list)
 607 {
 608         while (list) {
 609                 if (list->item == item)
 610                         return 1;
 611                 list = list->next;
 612         }
 613
 614         return 0;
 615 }
 616
 617 unsigned commit_list_count(const struct commit_list *l)
 618 {
 619         unsigned c = 0;
 620         for (; l; l = l->next )
 621                 c++;
 622         return c;
 623 }
 624
 625 struct commit_list *copy_commit_list(struct commit_list *list)
 626 {
 627         struct commit_list *head = NULL;
 628         struct commit_list **pp = &head;
 629         while (list) {
 630                 pp = commit_list_append(list->item, pp);
 631                 list = list->next;
 632         }
 633         return head;
 634 }
 635
 636 struct commit_list *reverse_commit_list(struct commit_list *list)
 637 {
 638         struct commit_list *next = NULL, *current, *backup;
 639         for (current = list; current; current = backup) {
 640                 backup = current->next;
 641                 current->next = next;
 642                 next = current;
 643         }
 644         return next;
 645 }
 646
 647 void free_commit_list(struct commit_list *list)
 648 {
 649         while (list)
 650                 pop_commit(&list);
 651 }
 652
 653 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 654 {
 655         struct commit_list **pp = list;
 656         struct commit_list *p;
 657         while ((p = *pp) != NULL) {
 658                 if (p->item->date < item->date) {
 659                         break;
 660                 }
 661                 pp = &p->next;
 662         }
 663         return commit_list_insert(item, pp);
 664 }
 665
 666 static int commit_list_compare_by_date(const struct commit_list *a,
 667                                        const struct commit_list *b)
 668 {
 669         timestamp_t a_date = a->item->date;
 670         timestamp_t b_date = b->item->date;
 671         if (a_date < b_date)
 672                 return 1;
 673         if (a_date > b_date)
 674                 return -1;
 675         return 0;
 676 }
 677
 678 DEFINE_LIST_SORT(static, commit_list_sort, struct commit_list, next);
 679
 680 void commit_list_sort_by_date(struct commit_list **list)
 681 {
 682         commit_list_sort(list, commit_list_compare_by_date);
 683 }
 684
 685 struct commit *pop_most_recent_commit(struct commit_list **list,
 686                                       unsigned int mark)
 687 {
 688         struct commit *ret = pop_commit(list);
 689         struct commit_list *parents = ret->parents;
 690
 691         while (parents) {
 692                 struct commit *commit = parents->item;
 693                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 694                         commit->object.flags |= mark;
 695                         commit_list_insert_by_date(commit, list);
 696                 }
 697                 parents = parents->next;
 698         }
 699         return ret;
 700 }
 701
 702 static void clear_commit_marks_1(struct commit_list **plist,
 703                                  struct commit *commit, unsigned int mark)
 704 {
 705         while (commit) {
 706                 struct commit_list *parents;
 707
 708                 if (!(mark & commit->object.flags))
 709                         return;
 710
 711                 commit->object.flags &= ~mark;
 712
 713                 parents = commit->parents;
 714                 if (!parents)
 715                         return;
 716
 717                 while ((parents = parents->next)) {
 718                         if (parents->item->object.flags & mark)
 719                                 commit_list_insert(parents->item, plist);
 720                 }
 721
 722                 commit = commit->parents->item;
 723         }
 724 }
 725
 726 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 727 {
 728         struct commit_list *list = NULL;
 729
 730         while (nr--) {
 731                 clear_commit_marks_1(&list, *commit, mark);
 732                 commit++;
 733         }
 734         while (list)
 735                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 736 }
 737
 738 void clear_commit_marks(struct commit *commit, unsigned int mark)
 739 {
 740         clear_commit_marks_many(1, &commit, mark);
 741 }
 742
 743 struct commit *pop_commit(struct commit_list **stack)
 744 {
 745         struct commit_list *top = *stack;
 746         struct commit *item = top ? top->item : NULL;
 747
 748         if (top) {
 749                 *stack = top->next;
 750                 free(top);
 751         }
 752         return item;
 753 }
 754
 755 /*
 756  * Topological sort support
 757  */
 758
 759 /* count number of children that have not been emitted */
 760 define_commit_slab(indegree_slab, int);
 761
 762 define_commit_slab(author_date_slab, timestamp_t);
 763
 764 void record_author_date(struct author_date_slab *author_date,
 765                         struct commit *commit)
 766 {
 767         const char *buffer = get_commit_buffer(commit, NULL);
 768         struct ident_split ident;
 769         const char *ident_line;
 770         size_t ident_len;
 771         char *date_end;
 772         timestamp_t date;
 773
 774         ident_line = find_commit_header(buffer, "author", &ident_len);
 775         if (!ident_line)
 776                 goto fail_exit; /* no author line */
 777         if (split_ident_line(&ident, ident_line, ident_len) ||
 778             !ident.date_begin || !ident.date_end)
 779                 goto fail_exit; /* malformed "author" line */
 780
 781         date = parse_timestamp(ident.date_begin, &date_end, 10);
 782         if (date_end != ident.date_end)
 783                 goto fail_exit; /* malformed date */
 784         *(author_date_slab_at(author_date, commit)) = date;
 785
 786 fail_exit:
 787         unuse_commit_buffer(commit, buffer);
 788 }
 789
 790 int compare_commits_by_author_date(const void *a_, const void *b_,
 791                                    void *cb_data)
 792 {
 793         const struct commit *a = a_, *b = b_;
 794         struct author_date_slab *author_date = cb_data;
 795         timestamp_t a_date = *(author_date_slab_at(author_date, a));
 796         timestamp_t b_date = *(author_date_slab_at(author_date, b));
 797
 798         /* newer commits with larger date first */
 799         if (a_date < b_date)
 800                 return 1;
 801         else if (a_date > b_date)
 802                 return -1;
 803         return 0;
 804 }
 805
 806 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_,
 807                                             void *unused UNUSED)
 808 {
 809         const struct commit *a = a_, *b = b_;
 810         const timestamp_t generation_a = commit_graph_generation(a),
 811                           generation_b = commit_graph_generation(b);
 812
 813         /* newer commits first */
 814         if (generation_a < generation_b)
 815                 return 1;
 816         else if (generation_a > generation_b)
 817                 return -1;
 818
 819         /* use date as a heuristic when generations are equal */
 820         if (a->date < b->date)
 821                 return 1;
 822         else if (a->date > b->date)
 823                 return -1;
 824         return 0;
 825 }
 826
 827 int compare_commits_by_commit_date(const void *a_, const void *b_,
 828                                    void *unused UNUSED)
 829 {
 830         const struct commit *a = a_, *b = b_;
 831         /* newer commits with larger date first */
 832         if (a->date < b->date)
 833                 return 1;
 834         else if (a->date > b->date)
 835                 return -1;
 836         return 0;
 837 }
 838
 839 /*
 840  * Performs an in-place topological sort on the list supplied.
 841  */
 842 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 843 {
 844         struct commit_list *next, *orig = *list;
 845         struct commit_list **pptr;
 846         struct indegree_slab indegree;
 847         struct prio_queue queue;
 848         struct commit *commit;
 849         struct author_date_slab author_date;
 850
 851         if (!orig)
 852                 return;
 853         *list = NULL;
 854
 855         init_indegree_slab(&indegree);
 856         memset(&queue, '\0', sizeof(queue));
 857
 858         switch (sort_order) {
 859         default: /* REV_SORT_IN_GRAPH_ORDER */
 860                 queue.compare = NULL;
 861                 break;
 862         case REV_SORT_BY_COMMIT_DATE:
 863                 queue.compare = compare_commits_by_commit_date;
 864                 break;
 865         case REV_SORT_BY_AUTHOR_DATE:
 866                 init_author_date_slab(&author_date);
 867                 queue.compare = compare_commits_by_author_date;
 868                 queue.cb_data = &author_date;
 869                 break;
 870         }
 871
 872         /* Mark them and clear the indegree */
 873         for (next = orig; next; next = next->next) {
 874                 struct commit *commit = next->item;
 875                 *(indegree_slab_at(&indegree, commit)) = 1;
 876                 /* also record the author dates, if needed */
 877                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 878                         record_author_date(&author_date, commit);
 879         }
 880
 881         /* update the indegree */
 882         for (next = orig; next; next = next->next) {
 883                 struct commit_list *parents = next->item->parents;
 884                 while (parents) {
 885                         struct commit *parent = parents->item;
 886                         int *pi = indegree_slab_at(&indegree, parent);
 887
 888                         if (*pi)
 889                                 (*pi)++;
 890                         parents = parents->next;
 891                 }
 892         }
 893
 894         /*
 895          * find the tips
 896          *
 897          * tips are nodes not reachable from any other node in the list
 898          *
 899          * the tips serve as a starting set for the work queue.
 900          */
 901         for (next = orig; next; next = next->next) {
 902                 struct commit *commit = next->item;
 903
 904                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 905                         prio_queue_put(&queue, commit);
 906         }
 907
 908         /*
 909          * This is unfortunate; the initial tips need to be shown
 910          * in the order given from the revision traversal machinery.
 911          */
 912         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 913                 prio_queue_reverse(&queue);
 914
 915         /* We no longer need the commit list */
 916         free_commit_list(orig);
 917
 918         pptr = list;
 919         *list = NULL;
 920         while ((commit = prio_queue_get(&queue)) != NULL) {
 921                 struct commit_list *parents;
 922
 923                 for (parents = commit->parents; parents ; parents = parents->next) {
 924                         struct commit *parent = parents->item;
 925                         int *pi = indegree_slab_at(&indegree, parent);
 926
 927                         if (!*pi)
 928                                 continue;
 929
 930                         /*
 931                          * parents are only enqueued for emission
 932                          * when all their children have been emitted thereby
 933                          * guaranteeing topological order.
 934                          */
 935                         if (--(*pi) == 1)
 936                                 prio_queue_put(&queue, parent);
 937                 }
 938                 /*
 939                  * all children of commit have already been
 940                  * emitted. we can emit it now.
 941                  */
 942                 *(indegree_slab_at(&indegree, commit)) = 0;
 943
 944                 pptr = &commit_list_insert(commit, pptr)->next;
 945         }
 946
 947         clear_indegree_slab(&indegree);
 948         clear_prio_queue(&queue);
 949         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 950                 clear_author_date_slab(&author_date);
 951 }
 952
 953 struct rev_collect {
 954         struct commit **commit;
 955         int nr;
 956         int alloc;
 957         unsigned int initial : 1;
 958 };
 959
 960 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 961 {
 962         struct commit *commit;
 963
 964         if (is_null_oid(oid))
 965                 return;
 966
 967         commit = lookup_commit(the_repository, oid);
 968         if (!commit ||
 969             (commit->object.flags & TMP_MARK) ||
 970             parse_commit(commit))
 971                 return;
 972
 973         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
 974         revs->commit[revs->nr++] = commit;
 975         commit->object.flags |= TMP_MARK;
 976 }
 977
 978 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 979                                   const char *ident UNUSED,
 980                                   timestamp_t timestamp UNUSED, int tz UNUSED,
 981                                   const char *message UNUSED, void *cbdata)
 982 {
 983         struct rev_collect *revs = cbdata;
 984
 985         if (revs->initial) {
 986                 revs->initial = 0;
 987                 add_one_commit(ooid, revs);
 988         }
 989         add_one_commit(noid, revs);
 990         return 0;
 991 }
 992
 993 struct commit *get_fork_point(const char *refname, struct commit *commit)
 994 {
 995         struct object_id oid;
 996         struct rev_collect revs;
 997         struct commit_list *bases;
 998         int i;
 999         struct commit *ret = NULL;
1000         char *full_refname;
1001
1002         switch (dwim_ref(refname, strlen(refname), &oid, &full_refname, 0)) {
1003         case 0:
1004                 die("No such ref: '%s'", refname);
1005         case 1:
1006                 break; /* good */
1007         default:
1008                 die("Ambiguous refname: '%s'", refname);
1009         }
1010
1011         memset(&revs, 0, sizeof(revs));
1012         revs.initial = 1;
1013         for_each_reflog_ent(full_refname, collect_one_reflog_ent, &revs);
1014
1015         if (!revs.nr)
1016                 add_one_commit(&oid, &revs);
1017
1018         for (i = 0; i < revs.nr; i++)
1019                 revs.commit[i]->object.flags &= ~TMP_MARK;
1020
1021         bases = get_merge_bases_many(commit, revs.nr, revs.commit);
1022
1023         /*
1024          * There should be one and only one merge base, when we found
1025          * a common ancestor among reflog entries.
1026          */
1027         if (!bases || bases->next)
1028                 goto cleanup_return;
1029
1030         /* And the found one must be one of the reflog entries */
1031         for (i = 0; i < revs.nr; i++)
1032                 if (&bases->item->object == &revs.commit[i]->object)
1033                         break; /* found */
1034         if (revs.nr <= i)
1035                 goto cleanup_return;
1036
1037         ret = bases->item;
1038
1039 cleanup_return:
1040         free(revs.commit);
1041         free_commit_list(bases);
1042         free(full_refname);
1043         return ret;
1044 }
1045
1046 /*
1047  * Indexed by hash algorithm identifier.
1048  */
1049 static const char *gpg_sig_headers[] = {
1050         NULL,
1051         "gpgsig",
1052         "gpgsig-sha256",
1053 };
1054
1055 int sign_with_header(struct strbuf *buf, const char *keyid)
1056 {
1057         struct strbuf sig = STRBUF_INIT;
1058         int inspos, copypos;
1059         const char *eoh;
1060         const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)];
1061         int gpg_sig_header_len = strlen(gpg_sig_header);
1062
1063         /* find the end of the header */
1064         eoh = strstr(buf->buf, "\n\n");
1065         if (!eoh)
1066                 inspos = buf->len;
1067         else
1068                 inspos = eoh - buf->buf + 1;
1069
1070         if (!keyid || !*keyid)
1071                 keyid = get_signing_key();
1072         if (sign_buffer(buf, &sig, keyid)) {
1073                 strbuf_release(&sig);
1074                 return -1;
1075         }
1076
1077         for (copypos = 0; sig.buf[copypos]; ) {
1078                 const char *bol = sig.buf + copypos;
1079                 const char *eol = strchrnul(bol, '\n');
1080                 int len = (eol - bol) + !!*eol;
1081
1082                 if (!copypos) {
1083                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1084                         inspos += gpg_sig_header_len;
1085                 }
1086                 strbuf_insertstr(buf, inspos++, " ");
1087                 strbuf_insert(buf, inspos, bol, len);
1088                 inspos += len;
1089                 copypos += len;
1090         }
1091         strbuf_release(&sig);
1092         return 0;
1093 }
1094
1095
1096
1097 int parse_signed_commit(const struct commit *commit,
1098                         struct strbuf *payload, struct strbuf *signature,
1099                         const struct git_hash_algo *algop)
1100 {
1101         unsigned long size;
1102         const char *buffer = get_commit_buffer(commit, &size);
1103         int ret = parse_buffer_signed_by_header(buffer, size, payload, signature, algop);
1104
1105         unuse_commit_buffer(commit, buffer);
1106         return ret;
1107 }
1108
1109 int parse_buffer_signed_by_header(const char *buffer,
1110                                   unsigned long size,
1111                                   struct strbuf *payload,
1112                                   struct strbuf *signature,
1113                                   const struct git_hash_algo *algop)
1114 {
1115         int in_signature = 0, saw_signature = 0, other_signature = 0;
1116         const char *line, *tail, *p;
1117         const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(algop)];
1118
1119         line = buffer;
1120         tail = buffer + size;
1121         while (line < tail) {
1122                 const char *sig = NULL;
1123                 const char *next = memchr(line, '\n', tail - line);
1124
1125                 next = next ? next + 1 : tail;
1126                 if (in_signature && line[0] == ' ')
1127                         sig = line + 1;
1128                 else if (skip_prefix(line, gpg_sig_header, &p) &&
1129                          *p == ' ') {
1130                         sig = line + strlen(gpg_sig_header) + 1;
1131                         other_signature = 0;
1132                 }
1133                 else if (starts_with(line, "gpgsig"))
1134                         other_signature = 1;
1135                 else if (other_signature && line[0] != ' ')
1136                         other_signature = 0;
1137                 if (sig) {
1138                         strbuf_add(signature, sig, next - sig);
1139                         saw_signature = 1;
1140                         in_signature = 1;
1141                 } else {
1142                         if (*line == '\n')
1143                                 /* dump the whole remainder of the buffer */
1144                                 next = tail;
1145                         if (!other_signature)
1146                                 strbuf_add(payload, line, next - line);
1147                         in_signature = 0;
1148                 }
1149                 line = next;
1150         }
1151         return saw_signature;
1152 }
1153
1154 int remove_signature(struct strbuf *buf)
1155 {
1156         const char *line = buf->buf;
1157         const char *tail = buf->buf + buf->len;
1158         int in_signature = 0;
1159         struct sigbuf {
1160                 const char *start;
1161                 const char *end;
1162         } sigs[2], *sigp = &sigs[0];
1163         int i;
1164         const char *orig_buf = buf->buf;
1165
1166         memset(sigs, 0, sizeof(sigs));
1167
1168         while (line < tail) {
1169                 const char *next = memchr(line, '\n', tail - line);
1170                 next = next ? next + 1 : tail;
1171
1172                 if (in_signature && line[0] == ' ')
1173                         sigp->end = next;
1174                 else if (starts_with(line, "gpgsig")) {
1175                         int i;
1176                         for (i = 1; i < GIT_HASH_NALGOS; i++) {
1177                                 const char *p;
1178                                 if (skip_prefix(line, gpg_sig_headers[i], &p) &&
1179                                     *p == ' ') {
1180                                         sigp->start = line;
1181                                         sigp->end = next;
1182                                         in_signature = 1;
1183                                 }
1184                         }
1185                 } else {
1186                         if (*line == '\n')
1187                                 /* dump the whole remainder of the buffer */
1188                                 next = tail;
1189                         if (in_signature && sigp - sigs != ARRAY_SIZE(sigs))
1190                                 sigp++;
1191                         in_signature = 0;
1192                 }
1193                 line = next;
1194         }
1195
1196         for (i = ARRAY_SIZE(sigs) - 1; i >= 0; i--)
1197                 if (sigs[i].start)
1198                         strbuf_remove(buf, sigs[i].start - orig_buf, sigs[i].end - sigs[i].start);
1199
1200         return sigs[0].start != NULL;
1201 }
1202
1203 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1204 {
1205         struct merge_remote_desc *desc;
1206         struct commit_extra_header *mergetag;
1207         char *buf;
1208         unsigned long size;
1209         enum object_type type;
1210         struct strbuf payload = STRBUF_INIT;
1211         struct strbuf signature = STRBUF_INIT;
1212
1213         desc = merge_remote_util(parent);
1214         if (!desc || !desc->obj)
1215                 return;
1216         buf = read_object_file(&desc->obj->oid, &type, &size);
1217         if (!buf || type != OBJ_TAG)
1218                 goto free_return;
1219         if (!parse_signature(buf, size, &payload, &signature))
1220                 goto free_return;
1221         /*
1222          * We could verify this signature and either omit the tag when
1223          * it does not validate, but the integrator may not have the
1224          * public key of the signer of the tag being merged, while a
1225          * later auditor may have it while auditing, so let's not run
1226          * verify-signed-buffer here for now...
1227          *
1228          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1229          *      warn("warning: signed tag unverified.");
1230          */
1231         CALLOC_ARRAY(mergetag, 1);
1232         mergetag->key = xstrdup("mergetag");
1233         mergetag->value = buf;
1234         mergetag->len = size;
1235
1236         **tail = mergetag;
1237         *tail = &mergetag->next;
1238         strbuf_release(&payload);
1239         strbuf_release(&signature);
1240         return;
1241
1242 free_return:
1243         free(buf);
1244 }
1245
1246 int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1247 {
1248         struct strbuf payload = STRBUF_INIT;
1249         struct strbuf signature = STRBUF_INIT;
1250         int ret = 1;
1251
1252         sigc->result = 'N';
1253
1254         if (parse_signed_commit(commit, &payload, &signature, the_hash_algo) <= 0)
1255                 goto out;
1256
1257         sigc->payload_type = SIGNATURE_PAYLOAD_COMMIT;
1258         sigc->payload = strbuf_detach(&payload, &sigc->payload_len);
1259         ret = check_signature(sigc, signature.buf, signature.len);
1260
1261  out:
1262         strbuf_release(&payload);
1263         strbuf_release(&signature);
1264
1265         return ret;
1266 }
1267
1268 void verify_merge_signature(struct commit *commit, int verbosity,
1269                             int check_trust)
1270 {
1271         char hex[GIT_MAX_HEXSZ + 1];
1272         struct signature_check signature_check;
1273         int ret;
1274         memset(&signature_check, 0, sizeof(signature_check));
1275
1276         ret = check_commit_signature(commit, &signature_check);
1277
1278         find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1279         switch (signature_check.result) {
1280         case 'G':
1281                 if (ret || (check_trust && signature_check.trust_level < TRUST_MARGINAL))
1282                         die(_("Commit %s has an untrusted GPG signature, "
1283                               "allegedly by %s."), hex, signature_check.signer);
1284                 break;
1285         case 'B':
1286                 die(_("Commit %s has a bad GPG signature "
1287                       "allegedly by %s."), hex, signature_check.signer);
1288         default: /* 'N' */
1289                 die(_("Commit %s does not have a GPG signature."), hex);
1290         }
1291         if (verbosity >= 0 && signature_check.result == 'G')
1292                 printf(_("Commit %s has a good GPG signature by %s\n"),
1293                        hex, signature_check.signer);
1294
1295         signature_check_clear(&signature_check);
1296 }
1297
1298 void append_merge_tag_headers(struct commit_list *parents,
1299                               struct commit_extra_header ***tail)
1300 {
1301         while (parents) {
1302                 struct commit *parent = parents->item;
1303                 handle_signed_tag(parent, tail);
1304                 parents = parents->next;
1305         }
1306 }
1307
1308 static void add_extra_header(struct strbuf *buffer,
1309                              struct commit_extra_header *extra)
1310 {
1311         strbuf_addstr(buffer, extra->key);
1312         if (extra->len)
1313                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1314         else
1315                 strbuf_addch(buffer, '\n');
1316 }
1317
1318 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1319                                                       const char **exclude)
1320 {
1321         struct commit_extra_header *extra = NULL;
1322         unsigned long size;
1323         const char *buffer = get_commit_buffer(commit, &size);
1324         extra = read_commit_extra_header_lines(buffer, size, exclude);
1325         unuse_commit_buffer(commit, buffer);
1326         return extra;
1327 }
1328
1329 int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1330 {
1331         struct commit_extra_header *extra, *to_free;
1332         int res = 0;
1333
1334         to_free = read_commit_extra_headers(commit, NULL);
1335         for (extra = to_free; !res && extra; extra = extra->next) {
1336                 if (strcmp(extra->key, "mergetag"))
1337                         continue; /* not a merge tag */
1338                 res = fn(commit, extra, data);
1339         }
1340         free_commit_extra_headers(to_free);
1341         return res;
1342 }
1343
1344 static inline int standard_header_field(const char *field, size_t len)
1345 {
1346         return ((len == 4 && !memcmp(field, "tree", 4)) ||
1347                 (len == 6 && !memcmp(field, "parent", 6)) ||
1348                 (len == 6 && !memcmp(field, "author", 6)) ||
1349                 (len == 9 && !memcmp(field, "committer", 9)) ||
1350                 (len == 8 && !memcmp(field, "encoding", 8)));
1351 }
1352
1353 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1354 {
1355         if (!exclude)
1356                 return 0;
1357
1358         while (*exclude) {
1359                 size_t xlen = strlen(*exclude);
1360                 if (len == xlen && !memcmp(field, *exclude, xlen))
1361                         return 1;
1362                 exclude++;
1363         }
1364         return 0;
1365 }
1366
1367 static struct commit_extra_header *read_commit_extra_header_lines(
1368         const char *buffer, size_t size,
1369         const char **exclude)
1370 {
1371         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1372         const char *line, *next, *eof, *eob;
1373         struct strbuf buf = STRBUF_INIT;
1374
1375         for (line = buffer, eob = line + size;
1376              line < eob && *line != '\n';
1377              line = next) {
1378                 next = memchr(line, '\n', eob - line);
1379                 next = next ? next + 1 : eob;
1380                 if (*line == ' ') {
1381                         /* continuation */
1382                         if (it)
1383                                 strbuf_add(&buf, line + 1, next - (line + 1));
1384                         continue;
1385                 }
1386                 if (it)
1387                         it->value = strbuf_detach(&buf, &it->len);
1388                 strbuf_reset(&buf);
1389                 it = NULL;
1390
1391                 eof = memchr(line, ' ', next - line);
1392                 if (!eof)
1393                         eof = next;
1394                 else if (standard_header_field(line, eof - line) ||
1395                          excluded_header_field(line, eof - line, exclude))
1396                         continue;
1397
1398                 CALLOC_ARRAY(it, 1);
1399                 it->key = xmemdupz(line, eof-line);
1400                 *tail = it;
1401                 tail = &it->next;
1402                 if (eof + 1 < next)
1403                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1404         }
1405         if (it)
1406                 it->value = strbuf_detach(&buf, &it->len);
1407         return extra;
1408 }
1409
1410 void free_commit_extra_headers(struct commit_extra_header *extra)
1411 {
1412         while (extra) {
1413                 struct commit_extra_header *next = extra->next;
1414                 free(extra->key);
1415                 free(extra->value);
1416                 free(extra);
1417                 extra = next;
1418         }
1419 }
1420
1421 int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
1422                 struct commit_list *parents, struct object_id *ret,
1423                 const char *author, const char *sign_commit)
1424 {
1425         struct commit_extra_header *extra = NULL, **tail = &extra;
1426         int result;
1427
1428         append_merge_tag_headers(parents, &tail);
1429         result = commit_tree_extended(msg, msg_len, tree, parents, ret, author,
1430                                       NULL, sign_commit, extra);
1431         free_commit_extra_headers(extra);
1432         return result;
1433 }
1434
1435 static int find_invalid_utf8(const char *buf, int len)
1436 {
1437         int offset = 0;
1438         static const unsigned int max_codepoint[] = {
1439                 0x7f, 0x7ff, 0xffff, 0x10ffff
1440         };
1441
1442         while (len) {
1443                 unsigned char c = *buf++;
1444                 int bytes, bad_offset;
1445                 unsigned int codepoint;
1446                 unsigned int min_val, max_val;
1447
1448                 len--;
1449                 offset++;
1450
1451                 /* Simple US-ASCII? No worries. */
1452                 if (c < 0x80)
1453                         continue;
1454
1455                 bad_offset = offset-1;
1456
1457                 /*
1458                  * Count how many more high bits set: that's how
1459                  * many more bytes this sequence should have.
1460                  */
1461                 bytes = 0;
1462                 while (c & 0x40) {
1463                         c <<= 1;
1464                         bytes++;
1465                 }
1466
1467                 /*
1468                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1469                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1470                  */
1471                 if (bytes < 1 || 3 < bytes)
1472                         return bad_offset;
1473
1474                 /* Do we *have* that many bytes? */
1475                 if (len < bytes)
1476                         return bad_offset;
1477
1478                 /*
1479                  * Place the encoded bits at the bottom of the value and compute the
1480                  * valid range.
1481                  */
1482                 codepoint = (c & 0x7f) >> bytes;
1483                 min_val = max_codepoint[bytes-1] + 1;
1484                 max_val = max_codepoint[bytes];
1485
1486                 offset += bytes;
1487                 len -= bytes;
1488
1489                 /* And verify that they are good continuation bytes */
1490                 do {
1491                         codepoint <<= 6;
1492                         codepoint |= *buf & 0x3f;
1493                         if ((*buf++ & 0xc0) != 0x80)
1494                                 return bad_offset;
1495                 } while (--bytes);
1496
1497                 /* Reject codepoints that are out of range for the sequence length. */
1498                 if (codepoint < min_val || codepoint > max_val)
1499                         return bad_offset;
1500                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1501                 if ((codepoint & 0x1ff800) == 0xd800)
1502                         return bad_offset;
1503                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1504                 if ((codepoint & 0xfffe) == 0xfffe)
1505                         return bad_offset;
1506                 /* So are anything in the range U+FDD0..U+FDEF. */
1507                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1508                         return bad_offset;
1509         }
1510         return -1;
1511 }
1512
1513 /*
1514  * This verifies that the buffer is in proper utf8 format.
1515  *
1516  * If it isn't, it assumes any non-utf8 characters are Latin1,
1517  * and does the conversion.
1518  */
1519 static int verify_utf8(struct strbuf *buf)
1520 {
1521         int ok = 1;
1522         long pos = 0;
1523
1524         for (;;) {
1525                 int bad;
1526                 unsigned char c;
1527                 unsigned char replace[2];
1528
1529                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1530                 if (bad < 0)
1531                         return ok;
1532                 pos += bad;
1533                 ok = 0;
1534                 c = buf->buf[pos];
1535                 strbuf_remove(buf, pos, 1);
1536
1537                 /* We know 'c' must be in the range 128-255 */
1538                 replace[0] = 0xc0 + (c >> 6);
1539                 replace[1] = 0x80 + (c & 0x3f);
1540                 strbuf_insert(buf, pos, replace, 2);
1541                 pos += 2;
1542         }
1543 }
1544
1545 static const char commit_utf8_warn[] =
1546 N_("Warning: commit message did not conform to UTF-8.\n"
1547    "You may want to amend it after fixing the message, or set the config\n"
1548    "variable i18n.commitEncoding to the encoding your project uses.\n");
1549
1550 int commit_tree_extended(const char *msg, size_t msg_len,
1551                          const struct object_id *tree,
1552                          struct commit_list *parents, struct object_id *ret,
1553                          const char *author, const char *committer,
1554                          const char *sign_commit,
1555                          struct commit_extra_header *extra)
1556 {
1557         int result;
1558         int encoding_is_utf8;
1559         struct strbuf buffer;
1560
1561         assert_oid_type(tree, OBJ_TREE);
1562
1563         if (memchr(msg, '\0', msg_len))
1564                 return error("a NUL byte in commit log message not allowed.");
1565
1566         /* Not having i18n.commitencoding is the same as having utf-8 */
1567         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1568
1569         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1570         strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
1571
1572         /*
1573          * NOTE! This ordering means that the same exact tree merged with a
1574          * different order of parents will be a _different_ changeset even
1575          * if everything else stays the same.
1576          */
1577         while (parents) {
1578                 struct commit *parent = pop_commit(&parents);
1579                 strbuf_addf(&buffer, "parent %s\n",
1580                             oid_to_hex(&parent->object.oid));
1581         }
1582
1583         /* Person/date information */
1584         if (!author)
1585                 author = git_author_info(IDENT_STRICT);
1586         strbuf_addf(&buffer, "author %s\n", author);
1587         if (!committer)
1588                 committer = git_committer_info(IDENT_STRICT);
1589         strbuf_addf(&buffer, "committer %s\n", committer);
1590         if (!encoding_is_utf8)
1591                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1592
1593         while (extra) {
1594                 add_extra_header(&buffer, extra);
1595                 extra = extra->next;
1596         }
1597         strbuf_addch(&buffer, '\n');
1598
1599         /* And add the comment */
1600         strbuf_add(&buffer, msg, msg_len);
1601
1602         /* And check the encoding */
1603         if (encoding_is_utf8 && !verify_utf8(&buffer))
1604                 fprintf(stderr, _(commit_utf8_warn));
1605
1606         if (sign_commit && sign_with_header(&buffer, sign_commit)) {
1607                 result = -1;
1608                 goto out;
1609         }
1610
1611         result = write_object_file(buffer.buf, buffer.len, OBJ_COMMIT, ret);
1612 out:
1613         strbuf_release(&buffer);
1614         return result;
1615 }
1616
1617 define_commit_slab(merge_desc_slab, struct merge_remote_desc *);
1618 static struct merge_desc_slab merge_desc_slab = COMMIT_SLAB_INIT(1, merge_desc_slab);
1619
1620 struct merge_remote_desc *merge_remote_util(struct commit *commit)
1621 {
1622         return *merge_desc_slab_at(&merge_desc_slab, commit);
1623 }
1624
1625 void set_merge_remote_desc(struct commit *commit,
1626                            const char *name, struct object *obj)
1627 {
1628         struct merge_remote_desc *desc;
1629         FLEX_ALLOC_STR(desc, name, name);
1630         desc->obj = obj;
1631         *merge_desc_slab_at(&merge_desc_slab, commit) = desc;
1632 }
1633
1634 struct commit *get_merge_parent(const char *name)
1635 {
1636         struct object *obj;
1637         struct commit *commit;
1638         struct object_id oid;
1639         if (get_oid(name, &oid))
1640                 return NULL;
1641         obj = parse_object(the_repository, &oid);
1642         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1643         if (commit && !merge_remote_util(commit))
1644                 set_merge_remote_desc(commit, name, obj);
1645         return commit;
1646 }
1647
1648 /*
1649  * Append a commit to the end of the commit_list.
1650  *
1651  * next starts by pointing to the variable that holds the head of an
1652  * empty commit_list, and is updated to point to the "next" field of
1653  * the last item on the list as new commits are appended.
1654  *
1655  * Usage example:
1656  *
1657  *     struct commit_list *list;
1658  *     struct commit_list **next = &list;
1659  *
1660  *     next = commit_list_append(c1, next);
1661  *     next = commit_list_append(c2, next);
1662  *     assert(commit_list_count(list) == 2);
1663  *     return list;
1664  */
1665 struct commit_list **commit_list_append(struct commit *commit,
1666                                         struct commit_list **next)
1667 {
1668         struct commit_list *new_commit = xmalloc(sizeof(struct commit_list));
1669         new_commit->item = commit;
1670         *next = new_commit;
1671         new_commit->next = NULL;
1672         return &new_commit->next;
1673 }
1674
1675 const char *find_header_mem(const char *msg, size_t len,
1676                         const char *key, size_t *out_len)
1677 {
1678         int key_len = strlen(key);
1679         const char *line = msg;
1680
1681         /*
1682          * NEEDSWORK: It's possible for strchrnul() to scan beyond the range
1683          * given by len. However, current callers are safe because they compute
1684          * len by scanning a NUL-terminated block of memory starting at msg.
1685          * Nonetheless, it would be better to ensure the function does not look
1686          * at msg beyond the len provided by the caller.
1687          */
1688         while (line && line < msg + len) {
1689                 const char *eol = strchrnul(line, '\n');
1690
1691                 if (line == eol)
1692                         return NULL;
1693
1694                 if (eol - line > key_len &&
1695                     !strncmp(line, key, key_len) &&
1696                     line[key_len] == ' ') {
1697                         *out_len = eol - line - key_len - 1;
1698                         return line + key_len + 1;
1699                 }
1700                 line = *eol ? eol + 1 : NULL;
1701         }
1702         return NULL;
1703 }
1704
1705 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1706 {
1707         return find_header_mem(msg, strlen(msg), key, out_len);
1708 }
1709 /*
1710  * Inspect the given string and determine the true "end" of the log message, in
1711  * order to find where to put a new Signed-off-by trailer.  Ignored are
1712  * trailing comment lines and blank lines.  To support "git commit -s
1713  * --amend" on an existing commit, we also ignore "Conflicts:".  To
1714  * support "git commit -v", we truncate at cut lines.
1715  *
1716  * Returns the number of bytes from the tail to ignore, to be fed as
1717  * the second parameter to append_signoff().
1718  */
1719 size_t ignore_non_trailer(const char *buf, size_t len)
1720 {
1721         size_t boc = 0;
1722         size_t bol = 0;
1723         int in_old_conflicts_block = 0;
1724         size_t cutoff = wt_status_locate_end(buf, len);
1725
1726         while (bol < cutoff) {
1727                 const char *next_line = memchr(buf + bol, '\n', len - bol);
1728
1729                 if (!next_line)
1730                         next_line = buf + len;
1731                 else
1732                         next_line++;
1733
1734                 if (buf[bol] == comment_line_char || buf[bol] == '\n') {
1735                         /* is this the first of the run of comments? */
1736                         if (!boc)
1737                                 boc = bol;
1738                         /* otherwise, it is just continuing */
1739                 } else if (starts_with(buf + bol, "Conflicts:\n")) {
1740                         in_old_conflicts_block = 1;
1741                         if (!boc)
1742                                 boc = bol;
1743                 } else if (in_old_conflicts_block && buf[bol] == '\t') {
1744                         ; /* a pathname in the conflicts block */
1745                 } else if (boc) {
1746                         /* the previous was not trailing comment */
1747                         boc = 0;
1748                         in_old_conflicts_block = 0;
1749                 }
1750                 bol = next_line - buf;
1751         }
1752         return boc ? len - boc : len - cutoff;
1753 }
1754
1755 int run_commit_hook(int editor_is_used, const char *index_file,
1756                     int *invoked_hook, const char *name, ...)
1757 {
1758         struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
1759         va_list args;
1760         const char *arg;
1761
1762         strvec_pushf(&opt.env, "GIT_INDEX_FILE=%s", index_file);
1763
1764         /*
1765          * Let the hook know that no editor will be launched.
1766          */
1767         if (!editor_is_used)
1768                 strvec_push(&opt.env, "GIT_EDITOR=:");
1769
1770         va_start(args, name);
1771         while ((arg = va_arg(args, const char *)))
1772                 strvec_push(&opt.args, arg);
1773         va_end(args);
1774
1775         opt.invoked_hook = invoked_hook;
1776         return run_hooks_opt(name, &opt);
1777 }