commit.c

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