commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "pkt-line.h"
   5 #include "utf8.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "notes.h"
   9 #include "gpg-interface.h"
  10 #include "mergesort.h"
  11 #include "commit-slab.h"
  12 #include "prio-queue.h"
  13 #include "sha1-lookup.h"
  14
  15 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  16
  17 int save_commit_buffer = 1;
  18
  19 const char *commit_type = "commit";
  20
  21 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  22                                               int quiet)
  23 {
  24         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  25
  26         if (!obj)
  27                 return NULL;
  28         return object_as_type(obj, OBJ_COMMIT, quiet);
  29 }
  30
  31 struct commit *lookup_commit_reference(const unsigned char *sha1)
  32 {
  33         return lookup_commit_reference_gently(sha1, 0);
  34 }
  35
  36 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  37 {
  38         struct commit *c = lookup_commit_reference(sha1);
  39         if (!c)
  40                 die(_("could not parse %s"), ref_name);
  41         if (hashcmp(sha1, c->object.sha1)) {
  42                 warning(_("%s %s is not a commit!"),
  43                         ref_name, sha1_to_hex(sha1));
  44         }
  45         return c;
  46 }
  47
  48 struct commit *lookup_commit(const unsigned char *sha1)
  49 {
  50         struct object *obj = lookup_object(sha1);
  51         if (!obj)
  52                 return create_object(sha1, alloc_commit_node());
  53         return object_as_type(obj, OBJ_COMMIT, 0);
  54 }
  55
  56 struct commit *lookup_commit_reference_by_name(const char *name)
  57 {
  58         struct object_id oid;
  59         struct commit *commit;
  60
  61         if (get_sha1_committish(name, oid.hash))
  62                 return NULL;
  63         commit = lookup_commit_reference(oid.hash);
  64         if (parse_commit(commit))
  65                 return NULL;
  66         return commit;
  67 }
  68
  69 static unsigned long parse_commit_date(const char *buf, const char *tail)
  70 {
  71         const char *dateptr;
  72
  73         if (buf + 6 >= tail)
  74                 return 0;
  75         if (memcmp(buf, "author", 6))
  76                 return 0;
  77         while (buf < tail && *buf++ != '\n')
  78                 /* nada */;
  79         if (buf + 9 >= tail)
  80                 return 0;
  81         if (memcmp(buf, "committer", 9))
  82                 return 0;
  83         while (buf < tail && *buf++ != '>')
  84                 /* nada */;
  85         if (buf >= tail)
  86                 return 0;
  87         dateptr = buf;
  88         while (buf < tail && *buf++ != '\n')
  89                 /* nada */;
  90         if (buf >= tail)
  91                 return 0;
  92         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  93         return strtoul(dateptr, NULL, 10);
  94 }
  95
  96 static struct commit_graft **commit_graft;
  97 static int commit_graft_alloc, commit_graft_nr;
  98
  99 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 100 {
 101         struct commit_graft **commit_graft_table = table;
 102         return commit_graft_table[index]->oid.hash;
 103 }
 104
 105 static int commit_graft_pos(const unsigned char *sha1)
 106 {
 107         return sha1_pos(sha1, commit_graft, commit_graft_nr,
 108                         commit_graft_sha1_access);
 109 }
 110
 111 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 112 {
 113         int pos = commit_graft_pos(graft->oid.hash);
 114
 115         if (0 <= pos) {
 116                 if (ignore_dups)
 117                         free(graft);
 118                 else {
 119                         free(commit_graft[pos]);
 120                         commit_graft[pos] = graft;
 121                 }
 122                 return 1;
 123         }
 124         pos = -pos - 1;
 125         ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 126         commit_graft_nr++;
 127         if (pos < commit_graft_nr)
 128                 memmove(commit_graft + pos + 1,
 129                         commit_graft + pos,
 130                         (commit_graft_nr - pos - 1) *
 131                         sizeof(*commit_graft));
 132         commit_graft[pos] = graft;
 133         return 0;
 134 }
 135
 136 struct commit_graft *read_graft_line(char *buf, int len)
 137 {
 138         /* The format is just "Commit Parent1 Parent2 ...\n" */
 139         int i;
 140         struct commit_graft *graft = NULL;
 141         const int entry_size = GIT_SHA1_HEXSZ + 1;
 142
 143         while (len && isspace(buf[len-1]))
 144                 buf[--len] = '\0';
 145         if (buf[0] == '#' || buf[0] == '\0')
 146                 return NULL;
 147         if ((len + 1) % entry_size)
 148                 goto bad_graft_data;
 149         i = (len + 1) / entry_size - 1;
 150         graft = xmalloc(sizeof(*graft) + GIT_SHA1_RAWSZ * i);
 151         graft->nr_parent = i;
 152         if (get_oid_hex(buf, &graft->oid))
 153                 goto bad_graft_data;
 154         for (i = GIT_SHA1_HEXSZ; i < len; i += entry_size) {
 155                 if (buf[i] != ' ')
 156                         goto bad_graft_data;
 157                 if (get_sha1_hex(buf + i + 1, graft->parent[i/entry_size].hash))
 158                         goto bad_graft_data;
 159         }
 160         return graft;
 161
 162 bad_graft_data:
 163         error("bad graft data: %s", buf);
 164         free(graft);
 165         return NULL;
 166 }
 167
 168 static int read_graft_file(const char *graft_file)
 169 {
 170         FILE *fp = fopen(graft_file, "r");
 171         struct strbuf buf = STRBUF_INIT;
 172         if (!fp)
 173                 return -1;
 174         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 175                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 176                 struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 177                 if (!graft)
 178                         continue;
 179                 if (register_commit_graft(graft, 1))
 180                         error("duplicate graft data: %s", buf.buf);
 181         }
 182         fclose(fp);
 183         strbuf_release(&buf);
 184         return 0;
 185 }
 186
 187 static void prepare_commit_graft(void)
 188 {
 189         static int commit_graft_prepared;
 190         char *graft_file;
 191
 192         if (commit_graft_prepared)
 193                 return;
 194         graft_file = get_graft_file();
 195         read_graft_file(graft_file);
 196         /* make sure shallows are read */
 197         is_repository_shallow();
 198         commit_graft_prepared = 1;
 199 }
 200
 201 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 202 {
 203         int pos;
 204         prepare_commit_graft();
 205         pos = commit_graft_pos(sha1);
 206         if (pos < 0)
 207                 return NULL;
 208         return commit_graft[pos];
 209 }
 210
 211 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 212 {
 213         int i, ret;
 214         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 215                 ret = fn(commit_graft[i], cb_data);
 216         return ret;
 217 }
 218
 219 int unregister_shallow(const unsigned char *sha1)
 220 {
 221         int pos = commit_graft_pos(sha1);
 222         if (pos < 0)
 223                 return -1;
 224         if (pos + 1 < commit_graft_nr)
 225                 memmove(commit_graft + pos, commit_graft + pos + 1,
 226                                 sizeof(struct commit_graft *)
 227                                 * (commit_graft_nr - pos - 1));
 228         commit_graft_nr--;
 229         return 0;
 230 }
 231
 232 struct commit_buffer {
 233         void *buffer;
 234         unsigned long size;
 235 };
 236 define_commit_slab(buffer_slab, struct commit_buffer);
 237 static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 238
 239 void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
 240 {
 241         struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 242         v->buffer = buffer;
 243         v->size = size;
 244 }
 245
 246 const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
 247 {
 248         struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 249         if (!v) {
 250                 if (sizep)
 251                         *sizep = 0;
 252                 return NULL;
 253         }
 254         if (sizep)
 255                 *sizep = v->size;
 256         return v->buffer;
 257 }
 258
 259 const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 260 {
 261         const void *ret = get_cached_commit_buffer(commit, sizep);
 262         if (!ret) {
 263                 enum object_type type;
 264                 unsigned long size;
 265                 ret = read_sha1_file(commit->object.sha1, &type, &size);
 266                 if (!ret)
 267                         die("cannot read commit object %s",
 268                             sha1_to_hex(commit->object.sha1));
 269                 if (type != OBJ_COMMIT)
 270                         die("expected commit for %s, got %s",
 271                             sha1_to_hex(commit->object.sha1), typename(type));
 272                 if (sizep)
 273                         *sizep = size;
 274         }
 275         return ret;
 276 }
 277
 278 void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 279 {
 280         struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 281         if (!(v && v->buffer == buffer))
 282                 free((void *)buffer);
 283 }
 284
 285 void free_commit_buffer(struct commit *commit)
 286 {
 287         struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 288         if (v) {
 289                 free(v->buffer);
 290                 v->buffer = NULL;
 291                 v->size = 0;
 292         }
 293 }
 294
 295 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 296 {
 297         struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 298         void *ret;
 299
 300         if (!v) {
 301                 if (sizep)
 302                         *sizep = 0;
 303                 return NULL;
 304         }
 305         ret = v->buffer;
 306         if (sizep)
 307                 *sizep = v->size;
 308
 309         v->buffer = NULL;
 310         v->size = 0;
 311         return ret;
 312 }
 313
 314 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 315 {
 316         const char *tail = buffer;
 317         const char *bufptr = buffer;
 318         struct object_id parent;
 319         struct commit_list **pptr;
 320         struct commit_graft *graft;
 321         const int tree_entry_len = GIT_SHA1_HEXSZ + 5;
 322         const int parent_entry_len = GIT_SHA1_HEXSZ + 7;
 323
 324         if (item->object.parsed)
 325                 return 0;
 326         item->object.parsed = 1;
 327         tail += size;
 328         if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 329                         bufptr[tree_entry_len] != '\n')
 330                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 331         if (get_sha1_hex(bufptr + 5, parent.hash) < 0)
 332                 return error("bad tree pointer in commit %s",
 333                              sha1_to_hex(item->object.sha1));
 334         item->tree = lookup_tree(parent.hash);
 335         bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 336         pptr = &item->parents;
 337
 338         graft = lookup_commit_graft(item->object.sha1);
 339         while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 340                 struct commit *new_parent;
 341
 342                 if (tail <= bufptr + parent_entry_len + 1 ||
 343                     get_sha1_hex(bufptr + 7, parent.hash) ||
 344                     bufptr[parent_entry_len] != '\n')
 345                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 346                 bufptr += parent_entry_len + 1;
 347                 /*
 348                  * The clone is shallow if nr_parent < 0, and we must
 349                  * not traverse its real parents even when we unhide them.
 350                  */
 351                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 352                         continue;
 353                 new_parent = lookup_commit(parent.hash);
 354                 if (new_parent)
 355                         pptr = &commit_list_insert(new_parent, pptr)->next;
 356         }
 357         if (graft) {
 358                 int i;
 359                 struct commit *new_parent;
 360                 for (i = 0; i < graft->nr_parent; i++) {
 361                         new_parent = lookup_commit(graft->parent[i].hash);
 362                         if (!new_parent)
 363                                 continue;
 364                         pptr = &commit_list_insert(new_parent, pptr)->next;
 365                 }
 366         }
 367         item->date = parse_commit_date(bufptr, tail);
 368
 369         return 0;
 370 }
 371
 372 int parse_commit_gently(struct commit *item, int quiet_on_missing)
 373 {
 374         enum object_type type;
 375         void *buffer;
 376         unsigned long size;
 377         int ret;
 378
 379         if (!item)
 380                 return -1;
 381         if (item->object.parsed)
 382                 return 0;
 383         buffer = read_sha1_file(item->object.sha1, &type, &size);
 384         if (!buffer)
 385                 return quiet_on_missing ? -1 :
 386                         error("Could not read %s",
 387                              sha1_to_hex(item->object.sha1));
 388         if (type != OBJ_COMMIT) {
 389                 free(buffer);
 390                 return error("Object %s not a commit",
 391                              sha1_to_hex(item->object.sha1));
 392         }
 393         ret = parse_commit_buffer(item, buffer, size);
 394         if (save_commit_buffer && !ret) {
 395                 set_commit_buffer(item, buffer, size);
 396                 return 0;
 397         }
 398         free(buffer);
 399         return ret;
 400 }
 401
 402 void parse_commit_or_die(struct commit *item)
 403 {
 404         if (parse_commit(item))
 405                 die("unable to parse commit %s",
 406                     item ? sha1_to_hex(item->object.sha1) : "(null)");
 407 }
 408
 409 int find_commit_subject(const char *commit_buffer, const char **subject)
 410 {
 411         const char *eol;
 412         const char *p = commit_buffer;
 413
 414         while (*p && (*p != '\n' || p[1] != '\n'))
 415                 p++;
 416         if (*p) {
 417                 p += 2;
 418                 for (eol = p; *eol && *eol != '\n'; eol++)
 419                         ; /* do nothing */
 420         } else
 421                 eol = p;
 422
 423         *subject = p;
 424
 425         return eol - p;
 426 }
 427
 428 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 429 {
 430         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 431         new_list->item = item;
 432         new_list->next = *list_p;
 433         *list_p = new_list;
 434         return new_list;
 435 }
 436
 437 unsigned commit_list_count(const struct commit_list *l)
 438 {
 439         unsigned c = 0;
 440         for (; l; l = l->next )
 441                 c++;
 442         return c;
 443 }
 444
 445 struct commit_list *copy_commit_list(struct commit_list *list)
 446 {
 447         struct commit_list *head = NULL;
 448         struct commit_list **pp = &head;
 449         while (list) {
 450                 pp = commit_list_append(list->item, pp);
 451                 list = list->next;
 452         }
 453         return head;
 454 }
 455
 456 void free_commit_list(struct commit_list *list)
 457 {
 458         while (list)
 459                 pop_commit(&list);
 460 }
 461
 462 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 463 {
 464         struct commit_list **pp = list;
 465         struct commit_list *p;
 466         while ((p = *pp) != NULL) {
 467                 if (p->item->date < item->date) {
 468                         break;
 469                 }
 470                 pp = &p->next;
 471         }
 472         return commit_list_insert(item, pp);
 473 }
 474
 475 static int commit_list_compare_by_date(const void *a, const void *b)
 476 {
 477         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 478         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 479         if (a_date < b_date)
 480                 return 1;
 481         if (a_date > b_date)
 482                 return -1;
 483         return 0;
 484 }
 485
 486 static void *commit_list_get_next(const void *a)
 487 {
 488         return ((const struct commit_list *)a)->next;
 489 }
 490
 491 static void commit_list_set_next(void *a, void *next)
 492 {
 493         ((struct commit_list *)a)->next = next;
 494 }
 495
 496 void commit_list_sort_by_date(struct commit_list **list)
 497 {
 498         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 499                                 commit_list_compare_by_date);
 500 }
 501
 502 struct commit *pop_most_recent_commit(struct commit_list **list,
 503                                       unsigned int mark)
 504 {
 505         struct commit *ret = pop_commit(list);
 506         struct commit_list *parents = ret->parents;
 507
 508         while (parents) {
 509                 struct commit *commit = parents->item;
 510                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 511                         commit->object.flags |= mark;
 512                         commit_list_insert_by_date(commit, list);
 513                 }
 514                 parents = parents->next;
 515         }
 516         return ret;
 517 }
 518
 519 static void clear_commit_marks_1(struct commit_list **plist,
 520                                  struct commit *commit, unsigned int mark)
 521 {
 522         while (commit) {
 523                 struct commit_list *parents;
 524
 525                 if (!(mark & commit->object.flags))
 526                         return;
 527
 528                 commit->object.flags &= ~mark;
 529
 530                 parents = commit->parents;
 531                 if (!parents)
 532                         return;
 533
 534                 while ((parents = parents->next))
 535                         commit_list_insert(parents->item, plist);
 536
 537                 commit = commit->parents->item;
 538         }
 539 }
 540
 541 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 542 {
 543         struct commit_list *list = NULL;
 544
 545         while (nr--) {
 546                 commit_list_insert(*commit, &list);
 547                 commit++;
 548         }
 549         while (list)
 550                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 551 }
 552
 553 void clear_commit_marks(struct commit *commit, unsigned int mark)
 554 {
 555         clear_commit_marks_many(1, &commit, mark);
 556 }
 557
 558 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 559 {
 560         struct object *object;
 561         struct commit *commit;
 562         unsigned int i;
 563
 564         for (i = 0; i < a->nr; i++) {
 565                 object = a->objects[i].item;
 566                 commit = lookup_commit_reference_gently(object->sha1, 1);
 567                 if (commit)
 568                         clear_commit_marks(commit, mark);
 569         }
 570 }
 571
 572 struct commit *pop_commit(struct commit_list **stack)
 573 {
 574         struct commit_list *top = *stack;
 575         struct commit *item = top ? top->item : NULL;
 576
 577         if (top) {
 578                 *stack = top->next;
 579                 free(top);
 580         }
 581         return item;
 582 }
 583
 584 /*
 585  * Topological sort support
 586  */
 587
 588 /* count number of children that have not been emitted */
 589 define_commit_slab(indegree_slab, int);
 590
 591 /* record author-date for each commit object */
 592 define_commit_slab(author_date_slab, unsigned long);
 593
 594 static void record_author_date(struct author_date_slab *author_date,
 595                                struct commit *commit)
 596 {
 597         const char *buffer = get_commit_buffer(commit, NULL);
 598         struct ident_split ident;
 599         const char *ident_line;
 600         size_t ident_len;
 601         char *date_end;
 602         unsigned long date;
 603
 604         ident_line = find_commit_header(buffer, "author", &ident_len);
 605         if (!ident_line)
 606                 goto fail_exit; /* no author line */
 607         if (split_ident_line(&ident, ident_line, ident_len) ||
 608             !ident.date_begin || !ident.date_end)
 609                 goto fail_exit; /* malformed "author" line */
 610
 611         date = strtoul(ident.date_begin, &date_end, 10);
 612         if (date_end != ident.date_end)
 613                 goto fail_exit; /* malformed date */
 614         *(author_date_slab_at(author_date, commit)) = date;
 615
 616 fail_exit:
 617         unuse_commit_buffer(commit, buffer);
 618 }
 619
 620 static int compare_commits_by_author_date(const void *a_, const void *b_,
 621                                           void *cb_data)
 622 {
 623         const struct commit *a = a_, *b = b_;
 624         struct author_date_slab *author_date = cb_data;
 625         unsigned long a_date = *(author_date_slab_at(author_date, a));
 626         unsigned long b_date = *(author_date_slab_at(author_date, b));
 627
 628         /* newer commits with larger date first */
 629         if (a_date < b_date)
 630                 return 1;
 631         else if (a_date > b_date)
 632                 return -1;
 633         return 0;
 634 }
 635
 636 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 637 {
 638         const struct commit *a = a_, *b = b_;
 639         /* newer commits with larger date first */
 640         if (a->date < b->date)
 641                 return 1;
 642         else if (a->date > b->date)
 643                 return -1;
 644         return 0;
 645 }
 646
 647 /*
 648  * Performs an in-place topological sort on the list supplied.
 649  */
 650 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 651 {
 652         struct commit_list *next, *orig = *list;
 653         struct commit_list **pptr;
 654         struct indegree_slab indegree;
 655         struct prio_queue queue;
 656         struct commit *commit;
 657         struct author_date_slab author_date;
 658
 659         if (!orig)
 660                 return;
 661         *list = NULL;
 662
 663         init_indegree_slab(&indegree);
 664         memset(&queue, '\0', sizeof(queue));
 665
 666         switch (sort_order) {
 667         default: /* REV_SORT_IN_GRAPH_ORDER */
 668                 queue.compare = NULL;
 669                 break;
 670         case REV_SORT_BY_COMMIT_DATE:
 671                 queue.compare = compare_commits_by_commit_date;
 672                 break;
 673         case REV_SORT_BY_AUTHOR_DATE:
 674                 init_author_date_slab(&author_date);
 675                 queue.compare = compare_commits_by_author_date;
 676                 queue.cb_data = &author_date;
 677                 break;
 678         }
 679
 680         /* Mark them and clear the indegree */
 681         for (next = orig; next; next = next->next) {
 682                 struct commit *commit = next->item;
 683                 *(indegree_slab_at(&indegree, commit)) = 1;
 684                 /* also record the author dates, if needed */
 685                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 686                         record_author_date(&author_date, commit);
 687         }
 688
 689         /* update the indegree */
 690         for (next = orig; next; next = next->next) {
 691                 struct commit_list *parents = next->item->parents;
 692                 while (parents) {
 693                         struct commit *parent = parents->item;
 694                         int *pi = indegree_slab_at(&indegree, parent);
 695
 696                         if (*pi)
 697                                 (*pi)++;
 698                         parents = parents->next;
 699                 }
 700         }
 701
 702         /*
 703          * find the tips
 704          *
 705          * tips are nodes not reachable from any other node in the list
 706          *
 707          * the tips serve as a starting set for the work queue.
 708          */
 709         for (next = orig; next; next = next->next) {
 710                 struct commit *commit = next->item;
 711
 712                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 713                         prio_queue_put(&queue, commit);
 714         }
 715
 716         /*
 717          * This is unfortunate; the initial tips need to be shown
 718          * in the order given from the revision traversal machinery.
 719          */
 720         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 721                 prio_queue_reverse(&queue);
 722
 723         /* We no longer need the commit list */
 724         free_commit_list(orig);
 725
 726         pptr = list;
 727         *list = NULL;
 728         while ((commit = prio_queue_get(&queue)) != NULL) {
 729                 struct commit_list *parents;
 730
 731                 for (parents = commit->parents; parents ; parents = parents->next) {
 732                         struct commit *parent = parents->item;
 733                         int *pi = indegree_slab_at(&indegree, parent);
 734
 735                         if (!*pi)
 736                                 continue;
 737
 738                         /*
 739                          * parents are only enqueued for emission
 740                          * when all their children have been emitted thereby
 741                          * guaranteeing topological order.
 742                          */
 743                         if (--(*pi) == 1)
 744                                 prio_queue_put(&queue, parent);
 745                 }
 746                 /*
 747                  * all children of commit have already been
 748                  * emitted. we can emit it now.
 749                  */
 750                 *(indegree_slab_at(&indegree, commit)) = 0;
 751
 752                 pptr = &commit_list_insert(commit, pptr)->next;
 753         }
 754
 755         clear_indegree_slab(&indegree);
 756         clear_prio_queue(&queue);
 757         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 758                 clear_author_date_slab(&author_date);
 759 }
 760
 761 /* merge-base stuff */
 762
 763 /* Remember to update object flag allocation in object.h */
 764 #define PARENT1         (1u<<16)
 765 #define PARENT2         (1u<<17)
 766 #define STALE           (1u<<18)
 767 #define RESULT          (1u<<19)
 768
 769 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 770
 771 static int queue_has_nonstale(struct prio_queue *queue)
 772 {
 773         int i;
 774         for (i = 0; i < queue->nr; i++) {
 775                 struct commit *commit = queue->array[i].data;
 776                 if (!(commit->object.flags & STALE))
 777                         return 1;
 778         }
 779         return 0;
 780 }
 781
 782 /* all input commits in one and twos[] must have been parsed! */
 783 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 784 {
 785         struct prio_queue queue = { compare_commits_by_commit_date };
 786         struct commit_list *result = NULL;
 787         int i;
 788
 789         one->object.flags |= PARENT1;
 790         if (!n) {
 791                 commit_list_append(one, &result);
 792                 return result;
 793         }
 794         prio_queue_put(&queue, one);
 795
 796         for (i = 0; i < n; i++) {
 797                 twos[i]->object.flags |= PARENT2;
 798                 prio_queue_put(&queue, twos[i]);
 799         }
 800
 801         while (queue_has_nonstale(&queue)) {
 802                 struct commit *commit = prio_queue_get(&queue);
 803                 struct commit_list *parents;
 804                 int flags;
 805
 806                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 807                 if (flags == (PARENT1 | PARENT2)) {
 808                         if (!(commit->object.flags & RESULT)) {
 809                                 commit->object.flags |= RESULT;
 810                                 commit_list_insert_by_date(commit, &result);
 811                         }
 812                         /* Mark parents of a found merge stale */
 813                         flags |= STALE;
 814                 }
 815                 parents = commit->parents;
 816                 while (parents) {
 817                         struct commit *p = parents->item;
 818                         parents = parents->next;
 819                         if ((p->object.flags & flags) == flags)
 820                                 continue;
 821                         if (parse_commit(p))
 822                                 return NULL;
 823                         p->object.flags |= flags;
 824                         prio_queue_put(&queue, p);
 825                 }
 826         }
 827
 828         clear_prio_queue(&queue);
 829         return result;
 830 }
 831
 832 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 833 {
 834         struct commit_list *list = NULL;
 835         struct commit_list *result = NULL;
 836         int i;
 837
 838         for (i = 0; i < n; i++) {
 839                 if (one == twos[i])
 840                         /*
 841                          * We do not mark this even with RESULT so we do not
 842                          * have to clean it up.
 843                          */
 844                         return commit_list_insert(one, &result);
 845         }
 846
 847         if (parse_commit(one))
 848                 return NULL;
 849         for (i = 0; i < n; i++) {
 850                 if (parse_commit(twos[i]))
 851                         return NULL;
 852         }
 853
 854         list = paint_down_to_common(one, n, twos);
 855
 856         while (list) {
 857                 struct commit *commit = pop_commit(&list);
 858                 if (!(commit->object.flags & STALE))
 859                         commit_list_insert_by_date(commit, &result);
 860         }
 861         return result;
 862 }
 863
 864 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 865 {
 866         struct commit_list *i, *j, *k, *ret = NULL;
 867
 868         if (!in)
 869                 return ret;
 870
 871         commit_list_insert(in->item, &ret);
 872
 873         for (i = in->next; i; i = i->next) {
 874                 struct commit_list *new = NULL, *end = NULL;
 875
 876                 for (j = ret; j; j = j->next) {
 877                         struct commit_list *bases;
 878                         bases = get_merge_bases(i->item, j->item);
 879                         if (!new)
 880                                 new = bases;
 881                         else
 882                                 end->next = bases;
 883                         for (k = bases; k; k = k->next)
 884                                 end = k;
 885                 }
 886                 ret = new;
 887         }
 888         return ret;
 889 }
 890
 891 static int remove_redundant(struct commit **array, int cnt)
 892 {
 893         /*
 894          * Some commit in the array may be an ancestor of
 895          * another commit.  Move such commit to the end of
 896          * the array, and return the number of commits that
 897          * are independent from each other.
 898          */
 899         struct commit **work;
 900         unsigned char *redundant;
 901         int *filled_index;
 902         int i, j, filled;
 903
 904         work = xcalloc(cnt, sizeof(*work));
 905         redundant = xcalloc(cnt, 1);
 906         filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 907
 908         for (i = 0; i < cnt; i++)
 909                 parse_commit(array[i]);
 910         for (i = 0; i < cnt; i++) {
 911                 struct commit_list *common;
 912
 913                 if (redundant[i])
 914                         continue;
 915                 for (j = filled = 0; j < cnt; j++) {
 916                         if (i == j || redundant[j])
 917                                 continue;
 918                         filled_index[filled] = j;
 919                         work[filled++] = array[j];
 920                 }
 921                 common = paint_down_to_common(array[i], filled, work);
 922                 if (array[i]->object.flags & PARENT2)
 923                         redundant[i] = 1;
 924                 for (j = 0; j < filled; j++)
 925                         if (work[j]->object.flags & PARENT1)
 926                                 redundant[filled_index[j]] = 1;
 927                 clear_commit_marks(array[i], all_flags);
 928                 for (j = 0; j < filled; j++)
 929                         clear_commit_marks(work[j], all_flags);
 930                 free_commit_list(common);
 931         }
 932
 933         /* Now collect the result */
 934         memcpy(work, array, sizeof(*array) * cnt);
 935         for (i = filled = 0; i < cnt; i++)
 936                 if (!redundant[i])
 937                         array[filled++] = work[i];
 938         for (j = filled, i = 0; i < cnt; i++)
 939                 if (redundant[i])
 940                         array[j++] = work[i];
 941         free(work);
 942         free(redundant);
 943         free(filled_index);
 944         return filled;
 945 }
 946
 947 static struct commit_list *get_merge_bases_many_0(struct commit *one,
 948                                                   int n,
 949                                                   struct commit **twos,
 950                                                   int cleanup)
 951 {
 952         struct commit_list *list;
 953         struct commit **rslt;
 954         struct commit_list *result;
 955         int cnt, i;
 956
 957         result = merge_bases_many(one, n, twos);
 958         for (i = 0; i < n; i++) {
 959                 if (one == twos[i])
 960                         return result;
 961         }
 962         if (!result || !result->next) {
 963                 if (cleanup) {
 964                         clear_commit_marks(one, all_flags);
 965                         clear_commit_marks_many(n, twos, all_flags);
 966                 }
 967                 return result;
 968         }
 969
 970         /* There are more than one */
 971         cnt = commit_list_count(result);
 972         rslt = xcalloc(cnt, sizeof(*rslt));
 973         for (list = result, i = 0; list; list = list->next)
 974                 rslt[i++] = list->item;
 975         free_commit_list(result);
 976
 977         clear_commit_marks(one, all_flags);
 978         clear_commit_marks_many(n, twos, all_flags);
 979
 980         cnt = remove_redundant(rslt, cnt);
 981         result = NULL;
 982         for (i = 0; i < cnt; i++)
 983                 commit_list_insert_by_date(rslt[i], &result);
 984         free(rslt);
 985         return result;
 986 }
 987
 988 struct commit_list *get_merge_bases_many(struct commit *one,
 989                                          int n,
 990                                          struct commit **twos)
 991 {
 992         return get_merge_bases_many_0(one, n, twos, 1);
 993 }
 994
 995 struct commit_list *get_merge_bases_many_dirty(struct commit *one,
 996                                                int n,
 997                                                struct commit **twos)
 998 {
 999         return get_merge_bases_many_0(one, n, twos, 0);
1000 }
1001
1002 struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
1003 {
1004         return get_merge_bases_many_0(one, 1, &two, 1);
1005 }
1006
1007 /*
1008  * Is "commit" a descendant of one of the elements on the "with_commit" list?
1009  */
1010 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1011 {
1012         if (!with_commit)
1013                 return 1;
1014         while (with_commit) {
1015                 struct commit *other;
1016
1017                 other = with_commit->item;
1018                 with_commit = with_commit->next;
1019                 if (in_merge_bases(other, commit))
1020                         return 1;
1021         }
1022         return 0;
1023 }
1024
1025 /*
1026  * Is "commit" an ancestor of one of the "references"?
1027  */
1028 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1029 {
1030         struct commit_list *bases;
1031         int ret = 0, i;
1032
1033         if (parse_commit(commit))
1034                 return ret;
1035         for (i = 0; i < nr_reference; i++)
1036                 if (parse_commit(reference[i]))
1037                         return ret;
1038
1039         bases = paint_down_to_common(commit, nr_reference, reference);
1040         if (commit->object.flags & PARENT2)
1041                 ret = 1;
1042         clear_commit_marks(commit, all_flags);
1043         clear_commit_marks_many(nr_reference, reference, all_flags);
1044         free_commit_list(bases);
1045         return ret;
1046 }
1047
1048 /*
1049  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1050  */
1051 int in_merge_bases(struct commit *commit, struct commit *reference)
1052 {
1053         return in_merge_bases_many(commit, 1, &reference);
1054 }
1055
1056 struct commit_list *reduce_heads(struct commit_list *heads)
1057 {
1058         struct commit_list *p;
1059         struct commit_list *result = NULL, **tail = &result;
1060         struct commit **array;
1061         int num_head, i;
1062
1063         if (!heads)
1064                 return NULL;
1065
1066         /* Uniquify */
1067         for (p = heads; p; p = p->next)
1068                 p->item->object.flags &= ~STALE;
1069         for (p = heads, num_head = 0; p; p = p->next) {
1070                 if (p->item->object.flags & STALE)
1071                         continue;
1072                 p->item->object.flags |= STALE;
1073                 num_head++;
1074         }
1075         array = xcalloc(num_head, sizeof(*array));
1076         for (p = heads, i = 0; p; p = p->next) {
1077                 if (p->item->object.flags & STALE) {
1078                         array[i++] = p->item;
1079                         p->item->object.flags &= ~STALE;
1080                 }
1081         }
1082         num_head = remove_redundant(array, num_head);
1083         for (i = 0; i < num_head; i++)
1084                 tail = &commit_list_insert(array[i], tail)->next;
1085         return result;
1086 }
1087
1088 static const char gpg_sig_header[] = "gpgsig";
1089 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1090
1091 static int do_sign_commit(struct strbuf *buf, const char *keyid)
1092 {
1093         struct strbuf sig = STRBUF_INIT;
1094         int inspos, copypos;
1095
1096         /* find the end of the header */
1097         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1098
1099         if (!keyid || !*keyid)
1100                 keyid = get_signing_key();
1101         if (sign_buffer(buf, &sig, keyid)) {
1102                 strbuf_release(&sig);
1103                 return -1;
1104         }
1105
1106         for (copypos = 0; sig.buf[copypos]; ) {
1107                 const char *bol = sig.buf + copypos;
1108                 const char *eol = strchrnul(bol, '\n');
1109                 int len = (eol - bol) + !!*eol;
1110
1111                 if (!copypos) {
1112                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1113                         inspos += gpg_sig_header_len;
1114                 }
1115                 strbuf_insert(buf, inspos++, " ", 1);
1116                 strbuf_insert(buf, inspos, bol, len);
1117                 inspos += len;
1118                 copypos += len;
1119         }
1120         strbuf_release(&sig);
1121         return 0;
1122 }
1123
1124 int parse_signed_commit(const struct commit *commit,
1125                         struct strbuf *payload, struct strbuf *signature)
1126 {
1127
1128         unsigned long size;
1129         const char *buffer = get_commit_buffer(commit, &size);
1130         int in_signature, saw_signature = -1;
1131         const char *line, *tail;
1132
1133         line = buffer;
1134         tail = buffer + size;
1135         in_signature = 0;
1136         saw_signature = 0;
1137         while (line < tail) {
1138                 const char *sig = NULL;
1139                 const char *next = memchr(line, '\n', tail - line);
1140
1141                 next = next ? next + 1 : tail;
1142                 if (in_signature && line[0] == ' ')
1143                         sig = line + 1;
1144                 else if (starts_with(line, gpg_sig_header) &&
1145                          line[gpg_sig_header_len] == ' ')
1146                         sig = line + gpg_sig_header_len + 1;
1147                 if (sig) {
1148                         strbuf_add(signature, sig, next - sig);
1149                         saw_signature = 1;
1150                         in_signature = 1;
1151                 } else {
1152                         if (*line == '\n')
1153                                 /* dump the whole remainder of the buffer */
1154                                 next = tail;
1155                         strbuf_add(payload, line, next - line);
1156                         in_signature = 0;
1157                 }
1158                 line = next;
1159         }
1160         unuse_commit_buffer(commit, buffer);
1161         return saw_signature;
1162 }
1163
1164 int remove_signature(struct strbuf *buf)
1165 {
1166         const char *line = buf->buf;
1167         const char *tail = buf->buf + buf->len;
1168         int in_signature = 0;
1169         const char *sig_start = NULL;
1170         const char *sig_end = NULL;
1171
1172         while (line < tail) {
1173                 const char *next = memchr(line, '\n', tail - line);
1174                 next = next ? next + 1 : tail;
1175
1176                 if (in_signature && line[0] == ' ')
1177                         sig_end = next;
1178                 else if (starts_with(line, gpg_sig_header) &&
1179                          line[gpg_sig_header_len] == ' ') {
1180                         sig_start = line;
1181                         sig_end = next;
1182                         in_signature = 1;
1183                 } else {
1184                         if (*line == '\n')
1185                                 /* dump the whole remainder of the buffer */
1186                                 next = tail;
1187                         in_signature = 0;
1188                 }
1189                 line = next;
1190         }
1191
1192         if (sig_start)
1193                 strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1194
1195         return sig_start != NULL;
1196 }
1197
1198 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1199 {
1200         struct merge_remote_desc *desc;
1201         struct commit_extra_header *mergetag;
1202         char *buf;
1203         unsigned long size, len;
1204         enum object_type type;
1205
1206         desc = merge_remote_util(parent);
1207         if (!desc || !desc->obj)
1208                 return;
1209         buf = read_sha1_file(desc->obj->sha1, &type, &size);
1210         if (!buf || type != OBJ_TAG)
1211                 goto free_return;
1212         len = parse_signature(buf, size);
1213         if (size == len)
1214                 goto free_return;
1215         /*
1216          * We could verify this signature and either omit the tag when
1217          * it does not validate, but the integrator may not have the
1218          * public key of the signer of the tag he is merging, while a
1219          * later auditor may have it while auditing, so let's not run
1220          * verify-signed-buffer here for now...
1221          *
1222          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1223          *      warn("warning: signed tag unverified.");
1224          */
1225         mergetag = xcalloc(1, sizeof(*mergetag));
1226         mergetag->key = xstrdup("mergetag");
1227         mergetag->value = buf;
1228         mergetag->len = size;
1229
1230         **tail = mergetag;
1231         *tail = &mergetag->next;
1232         return;
1233
1234 free_return:
1235         free(buf);
1236 }
1237
1238 int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1239 {
1240         struct strbuf payload = STRBUF_INIT;
1241         struct strbuf signature = STRBUF_INIT;
1242         int ret = 1;
1243
1244         sigc->result = 'N';
1245
1246         if (parse_signed_commit(commit, &payload, &signature) <= 0)
1247                 goto out;
1248         ret = check_signature(payload.buf, payload.len, signature.buf,
1249                 signature.len, sigc);
1250
1251  out:
1252         strbuf_release(&payload);
1253         strbuf_release(&signature);
1254
1255         return ret;
1256 }
1257
1258
1259
1260 void append_merge_tag_headers(struct commit_list *parents,
1261                               struct commit_extra_header ***tail)
1262 {
1263         while (parents) {
1264                 struct commit *parent = parents->item;
1265                 handle_signed_tag(parent, tail);
1266                 parents = parents->next;
1267         }
1268 }
1269
1270 static void add_extra_header(struct strbuf *buffer,
1271                              struct commit_extra_header *extra)
1272 {
1273         strbuf_addstr(buffer, extra->key);
1274         if (extra->len)
1275                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1276         else
1277                 strbuf_addch(buffer, '\n');
1278 }
1279
1280 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1281                                                       const char **exclude)
1282 {
1283         struct commit_extra_header *extra = NULL;
1284         unsigned long size;
1285         const char *buffer = get_commit_buffer(commit, &size);
1286         extra = read_commit_extra_header_lines(buffer, size, exclude);
1287         unuse_commit_buffer(commit, buffer);
1288         return extra;
1289 }
1290
1291 void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1292 {
1293         struct commit_extra_header *extra, *to_free;
1294
1295         to_free = read_commit_extra_headers(commit, NULL);
1296         for (extra = to_free; extra; extra = extra->next) {
1297                 if (strcmp(extra->key, "mergetag"))
1298                         continue; /* not a merge tag */
1299                 fn(commit, extra, data);
1300         }
1301         free_commit_extra_headers(to_free);
1302 }
1303
1304 static inline int standard_header_field(const char *field, size_t len)
1305 {
1306         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1307                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1308                 (len == 6 && !memcmp(field, "author ", 7)) ||
1309                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1310                 (len == 8 && !memcmp(field, "encoding ", 9)));
1311 }
1312
1313 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1314 {
1315         if (!exclude)
1316                 return 0;
1317
1318         while (*exclude) {
1319                 size_t xlen = strlen(*exclude);
1320                 if (len == xlen &&
1321                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1322                         return 1;
1323                 exclude++;
1324         }
1325         return 0;
1326 }
1327
1328 static struct commit_extra_header *read_commit_extra_header_lines(
1329         const char *buffer, size_t size,
1330         const char **exclude)
1331 {
1332         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1333         const char *line, *next, *eof, *eob;
1334         struct strbuf buf = STRBUF_INIT;
1335
1336         for (line = buffer, eob = line + size;
1337              line < eob && *line != '\n';
1338              line = next) {
1339                 next = memchr(line, '\n', eob - line);
1340                 next = next ? next + 1 : eob;
1341                 if (*line == ' ') {
1342                         /* continuation */
1343                         if (it)
1344                                 strbuf_add(&buf, line + 1, next - (line + 1));
1345                         continue;
1346                 }
1347                 if (it)
1348                         it->value = strbuf_detach(&buf, &it->len);
1349                 strbuf_reset(&buf);
1350                 it = NULL;
1351
1352                 eof = strchr(line, ' ');
1353                 if (next <= eof)
1354                         eof = next;
1355
1356                 if (standard_header_field(line, eof - line) ||
1357                     excluded_header_field(line, eof - line, exclude))
1358                         continue;
1359
1360                 it = xcalloc(1, sizeof(*it));
1361                 it->key = xmemdupz(line, eof-line);
1362                 *tail = it;
1363                 tail = &it->next;
1364                 if (eof + 1 < next)
1365                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1366         }
1367         if (it)
1368                 it->value = strbuf_detach(&buf, &it->len);
1369         return extra;
1370 }
1371
1372 void free_commit_extra_headers(struct commit_extra_header *extra)
1373 {
1374         while (extra) {
1375                 struct commit_extra_header *next = extra->next;
1376                 free(extra->key);
1377                 free(extra->value);
1378                 free(extra);
1379                 extra = next;
1380         }
1381 }
1382
1383 int commit_tree(const char *msg, size_t msg_len,
1384                 const unsigned char *tree,
1385                 struct commit_list *parents, unsigned char *ret,
1386                 const char *author, const char *sign_commit)
1387 {
1388         struct commit_extra_header *extra = NULL, **tail = &extra;
1389         int result;
1390
1391         append_merge_tag_headers(parents, &tail);
1392         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1393                                       author, sign_commit, extra);
1394         free_commit_extra_headers(extra);
1395         return result;
1396 }
1397
1398 static int find_invalid_utf8(const char *buf, int len)
1399 {
1400         int offset = 0;
1401         static const unsigned int max_codepoint[] = {
1402                 0x7f, 0x7ff, 0xffff, 0x10ffff
1403         };
1404
1405         while (len) {
1406                 unsigned char c = *buf++;
1407                 int bytes, bad_offset;
1408                 unsigned int codepoint;
1409                 unsigned int min_val, max_val;
1410
1411                 len--;
1412                 offset++;
1413
1414                 /* Simple US-ASCII? No worries. */
1415                 if (c < 0x80)
1416                         continue;
1417
1418                 bad_offset = offset-1;
1419
1420                 /*
1421                  * Count how many more high bits set: that's how
1422                  * many more bytes this sequence should have.
1423                  */
1424                 bytes = 0;
1425                 while (c & 0x40) {
1426                         c <<= 1;
1427                         bytes++;
1428                 }
1429
1430                 /*
1431                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1432                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1433                  */
1434                 if (bytes < 1 || 3 < bytes)
1435                         return bad_offset;
1436
1437                 /* Do we *have* that many bytes? */
1438                 if (len < bytes)
1439                         return bad_offset;
1440
1441                 /*
1442                  * Place the encoded bits at the bottom of the value and compute the
1443                  * valid range.
1444                  */
1445                 codepoint = (c & 0x7f) >> bytes;
1446                 min_val = max_codepoint[bytes-1] + 1;
1447                 max_val = max_codepoint[bytes];
1448
1449                 offset += bytes;
1450                 len -= bytes;
1451
1452                 /* And verify that they are good continuation bytes */
1453                 do {
1454                         codepoint <<= 6;
1455                         codepoint |= *buf & 0x3f;
1456                         if ((*buf++ & 0xc0) != 0x80)
1457                                 return bad_offset;
1458                 } while (--bytes);
1459
1460                 /* Reject codepoints that are out of range for the sequence length. */
1461                 if (codepoint < min_val || codepoint > max_val)
1462                         return bad_offset;
1463                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1464                 if ((codepoint & 0x1ff800) == 0xd800)
1465                         return bad_offset;
1466                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1467                 if ((codepoint & 0xfffe) == 0xfffe)
1468                         return bad_offset;
1469                 /* So are anything in the range U+FDD0..U+FDEF. */
1470                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1471                         return bad_offset;
1472         }
1473         return -1;
1474 }
1475
1476 /*
1477  * This verifies that the buffer is in proper utf8 format.
1478  *
1479  * If it isn't, it assumes any non-utf8 characters are Latin1,
1480  * and does the conversion.
1481  */
1482 static int verify_utf8(struct strbuf *buf)
1483 {
1484         int ok = 1;
1485         long pos = 0;
1486
1487         for (;;) {
1488                 int bad;
1489                 unsigned char c;
1490                 unsigned char replace[2];
1491
1492                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1493                 if (bad < 0)
1494                         return ok;
1495                 pos += bad;
1496                 ok = 0;
1497                 c = buf->buf[pos];
1498                 strbuf_remove(buf, pos, 1);
1499
1500                 /* We know 'c' must be in the range 128-255 */
1501                 replace[0] = 0xc0 + (c >> 6);
1502                 replace[1] = 0x80 + (c & 0x3f);
1503                 strbuf_insert(buf, pos, replace, 2);
1504                 pos += 2;
1505         }
1506 }
1507
1508 static const char commit_utf8_warn[] =
1509 "Warning: commit message did not conform to UTF-8.\n"
1510 "You may want to amend it after fixing the message, or set the config\n"
1511 "variable i18n.commitencoding to the encoding your project uses.\n";
1512
1513 int commit_tree_extended(const char *msg, size_t msg_len,
1514                          const unsigned char *tree,
1515                          struct commit_list *parents, unsigned char *ret,
1516                          const char *author, const char *sign_commit,
1517                          struct commit_extra_header *extra)
1518 {
1519         int result;
1520         int encoding_is_utf8;
1521         struct strbuf buffer;
1522
1523         assert_sha1_type(tree, OBJ_TREE);
1524
1525         if (memchr(msg, '\0', msg_len))
1526                 return error("a NUL byte in commit log message not allowed.");
1527
1528         /* Not having i18n.commitencoding is the same as having utf-8 */
1529         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1530
1531         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1532         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1533
1534         /*
1535          * NOTE! This ordering means that the same exact tree merged with a
1536          * different order of parents will be a _different_ changeset even
1537          * if everything else stays the same.
1538          */
1539         while (parents) {
1540                 struct commit *parent = pop_commit(&parents);
1541                 strbuf_addf(&buffer, "parent %s\n",
1542                             sha1_to_hex(parent->object.sha1));
1543         }
1544
1545         /* Person/date information */
1546         if (!author)
1547                 author = git_author_info(IDENT_STRICT);
1548         strbuf_addf(&buffer, "author %s\n", author);
1549         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1550         if (!encoding_is_utf8)
1551                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1552
1553         while (extra) {
1554                 add_extra_header(&buffer, extra);
1555                 extra = extra->next;
1556         }
1557         strbuf_addch(&buffer, '\n');
1558
1559         /* And add the comment */
1560         strbuf_add(&buffer, msg, msg_len);
1561
1562         /* And check the encoding */
1563         if (encoding_is_utf8 && !verify_utf8(&buffer))
1564                 fprintf(stderr, commit_utf8_warn);
1565
1566         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1567                 return -1;
1568
1569         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1570         strbuf_release(&buffer);
1571         return result;
1572 }
1573
1574 struct commit *get_merge_parent(const char *name)
1575 {
1576         struct object *obj;
1577         struct commit *commit;
1578         struct object_id oid;
1579         if (get_sha1(name, oid.hash))
1580                 return NULL;
1581         obj = parse_object(oid.hash);
1582         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1583         if (commit && !commit->util) {
1584                 struct merge_remote_desc *desc;
1585                 desc = xmalloc(sizeof(*desc));
1586                 desc->obj = obj;
1587                 desc->name = strdup(name);
1588                 commit->util = desc;
1589         }
1590         return commit;
1591 }
1592
1593 /*
1594  * Append a commit to the end of the commit_list.
1595  *
1596  * next starts by pointing to the variable that holds the head of an
1597  * empty commit_list, and is updated to point to the "next" field of
1598  * the last item on the list as new commits are appended.
1599  *
1600  * Usage example:
1601  *
1602  *     struct commit_list *list;
1603  *     struct commit_list **next = &list;
1604  *
1605  *     next = commit_list_append(c1, next);
1606  *     next = commit_list_append(c2, next);
1607  *     assert(commit_list_count(list) == 2);
1608  *     return list;
1609  */
1610 struct commit_list **commit_list_append(struct commit *commit,
1611                                         struct commit_list **next)
1612 {
1613         struct commit_list *new = xmalloc(sizeof(struct commit_list));
1614         new->item = commit;
1615         *next = new;
1616         new->next = NULL;
1617         return &new->next;
1618 }
1619
1620 void print_commit_list(struct commit_list *list,
1621                        const char *format_cur,
1622                        const char *format_last)
1623 {
1624         for ( ; list; list = list->next) {
1625                 const char *format = list->next ? format_cur : format_last;
1626                 printf(format, sha1_to_hex(list->item->object.sha1));
1627         }
1628 }
1629
1630 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1631 {
1632         int key_len = strlen(key);
1633         const char *line = msg;
1634
1635         while (line) {
1636                 const char *eol = strchrnul(line, '\n');
1637
1638                 if (line == eol)
1639                         return NULL;
1640
1641                 if (eol - line > key_len &&
1642                     !strncmp(line, key, key_len) &&
1643                     line[key_len] == ' ') {
1644                         *out_len = eol - line - key_len - 1;
1645                         return line + key_len + 1;
1646                 }
1647                 line = *eol ? eol + 1 : NULL;
1648         }
1649         return NULL;
1650 }
1651
1652 /*
1653  * Inspect sb and determine the true "end" of the log message, in
1654  * order to find where to put a new Signed-off-by: line.  Ignored are
1655  * trailing comment lines and blank lines, and also the traditional
1656  * "Conflicts:" block that is not commented out, so that we can use
1657  * "git commit -s --amend" on an existing commit that forgot to remove
1658  * it.
1659  *
1660  * Returns the number of bytes from the tail to ignore, to be fed as
1661  * the second parameter to append_signoff().
1662  */
1663 int ignore_non_trailer(struct strbuf *sb)
1664 {
1665         int boc = 0;
1666         int bol = 0;
1667         int in_old_conflicts_block = 0;
1668
1669         while (bol < sb->len) {
1670                 char *next_line;
1671
1672                 if (!(next_line = memchr(sb->buf + bol, '\n', sb->len - bol)))
1673                         next_line = sb->buf + sb->len;
1674                 else
1675                         next_line++;
1676
1677                 if (sb->buf[bol] == comment_line_char || sb->buf[bol] == '\n') {
1678                         /* is this the first of the run of comments? */
1679                         if (!boc)
1680                                 boc = bol;
1681                         /* otherwise, it is just continuing */
1682                 } else if (starts_with(sb->buf + bol, "Conflicts:\n")) {
1683                         in_old_conflicts_block = 1;
1684                         if (!boc)
1685                                 boc = bol;
1686                 } else if (in_old_conflicts_block && sb->buf[bol] == '\t') {
1687                         ; /* a pathname in the conflicts block */
1688                 } else if (boc) {
1689                         /* the previous was not trailing comment */
1690                         boc = 0;
1691                         in_old_conflicts_block = 0;
1692                 }
1693                 bol = next_line - sb->buf;
1694         }
1695         return boc ? sb->len - boc : 0;
1696 }