commit.c

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