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