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
  12 int save_commit_buffer = 1;
  13
  14 const char *commit_type = "commit";
  15
  16 static struct commit *check_commit(struct object *obj,
  17                                    const unsigned char *sha1,
  18                                    int quiet)
  19 {
  20         if (obj->type != OBJ_COMMIT) {
  21                 if (!quiet)
  22                         error("Object %s is a %s, not a commit",
  23                               sha1_to_hex(sha1), typename(obj->type));
  24                 return NULL;
  25         }
  26         return (struct commit *) obj;
  27 }
  28
  29 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  30                                               int quiet)
  31 {
  32         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  33
  34         if (!obj)
  35                 return NULL;
  36         return check_commit(obj, sha1, quiet);
  37 }
  38
  39 struct commit *lookup_commit_reference(const unsigned char *sha1)
  40 {
  41         return lookup_commit_reference_gently(sha1, 0);
  42 }
  43
  44 struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  45 {
  46         struct commit *c = lookup_commit_reference(sha1);
  47         if (!c)
  48                 die(_("could not parse %s"), ref_name);
  49         if (hashcmp(sha1, c->object.sha1)) {
  50                 warning(_("%s %s is not a commit!"),
  51                         ref_name, sha1_to_hex(sha1));
  52         }
  53         return c;
  54 }
  55
  56 struct commit *lookup_commit(const unsigned char *sha1)
  57 {
  58         struct object *obj = lookup_object(sha1);
  59         if (!obj)
  60                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  61         if (!obj->type)
  62                 obj->type = OBJ_COMMIT;
  63         return check_commit(obj, sha1, 0);
  64 }
  65
  66 struct commit *lookup_commit_reference_by_name(const char *name)
  67 {
  68         unsigned char sha1[20];
  69         struct commit *commit;
  70
  71         if (get_sha1(name, sha1))
  72                 return NULL;
  73         commit = lookup_commit_reference(sha1);
  74         if (!commit || parse_commit(commit))
  75                 return NULL;
  76         return commit;
  77 }
  78
  79 static unsigned long parse_commit_date(const char *buf, const char *tail)
  80 {
  81         const char *dateptr;
  82
  83         if (buf + 6 >= tail)
  84                 return 0;
  85         if (memcmp(buf, "author", 6))
  86                 return 0;
  87         while (buf < tail && *buf++ != '\n')
  88                 /* nada */;
  89         if (buf + 9 >= tail)
  90                 return 0;
  91         if (memcmp(buf, "committer", 9))
  92                 return 0;
  93         while (buf < tail && *buf++ != '>')
  94                 /* nada */;
  95         if (buf >= tail)
  96                 return 0;
  97         dateptr = buf;
  98         while (buf < tail && *buf++ != '\n')
  99                 /* nada */;
 100         if (buf >= tail)
 101                 return 0;
 102         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 103         return strtoul(dateptr, NULL, 10);
 104 }
 105
 106 static struct commit_graft **commit_graft;
 107 static int commit_graft_alloc, commit_graft_nr;
 108
 109 static int commit_graft_pos(const unsigned char *sha1)
 110 {
 111         int lo, hi;
 112         lo = 0;
 113         hi = commit_graft_nr;
 114         while (lo < hi) {
 115                 int mi = (lo + hi) / 2;
 116                 struct commit_graft *graft = commit_graft[mi];
 117                 int cmp = hashcmp(sha1, graft->sha1);
 118                 if (!cmp)
 119                         return mi;
 120                 if (cmp < 0)
 121                         hi = mi;
 122                 else
 123                         lo = mi + 1;
 124         }
 125         return -lo - 1;
 126 }
 127
 128 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 129 {
 130         int pos = commit_graft_pos(graft->sha1);
 131
 132         if (0 <= pos) {
 133                 if (ignore_dups)
 134                         free(graft);
 135                 else {
 136                         free(commit_graft[pos]);
 137                         commit_graft[pos] = graft;
 138                 }
 139                 return 1;
 140         }
 141         pos = -pos - 1;
 142         if (commit_graft_alloc <= ++commit_graft_nr) {
 143                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 144                 commit_graft = xrealloc(commit_graft,
 145                                         sizeof(*commit_graft) *
 146                                         commit_graft_alloc);
 147         }
 148         if (pos < commit_graft_nr)
 149                 memmove(commit_graft + pos + 1,
 150                         commit_graft + pos,
 151                         (commit_graft_nr - pos - 1) *
 152                         sizeof(*commit_graft));
 153         commit_graft[pos] = graft;
 154         return 0;
 155 }
 156
 157 struct commit_graft *read_graft_line(char *buf, int len)
 158 {
 159         /* The format is just "Commit Parent1 Parent2 ...\n" */
 160         int i;
 161         struct commit_graft *graft = NULL;
 162
 163         while (len && isspace(buf[len-1]))
 164                 buf[--len] = '\0';
 165         if (buf[0] == '#' || buf[0] == '\0')
 166                 return NULL;
 167         if ((len + 1) % 41)
 168                 goto bad_graft_data;
 169         i = (len + 1) / 41 - 1;
 170         graft = xmalloc(sizeof(*graft) + 20 * i);
 171         graft->nr_parent = i;
 172         if (get_sha1_hex(buf, graft->sha1))
 173                 goto bad_graft_data;
 174         for (i = 40; i < len; i += 41) {
 175                 if (buf[i] != ' ')
 176                         goto bad_graft_data;
 177                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 178                         goto bad_graft_data;
 179         }
 180         return graft;
 181
 182 bad_graft_data:
 183         error("bad graft data: %s", buf);
 184         free(graft);
 185         return NULL;
 186 }
 187
 188 static int read_graft_file(const char *graft_file)
 189 {
 190         FILE *fp = fopen(graft_file, "r");
 191         char buf[1024];
 192         if (!fp)
 193                 return -1;
 194         while (fgets(buf, sizeof(buf), fp)) {
 195                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 196                 int len = strlen(buf);
 197                 struct commit_graft *graft = read_graft_line(buf, len);
 198                 if (!graft)
 199                         continue;
 200                 if (register_commit_graft(graft, 1))
 201                         error("duplicate graft data: %s", buf);
 202         }
 203         fclose(fp);
 204         return 0;
 205 }
 206
 207 static void prepare_commit_graft(void)
 208 {
 209         static int commit_graft_prepared;
 210         char *graft_file;
 211
 212         if (commit_graft_prepared)
 213                 return;
 214         graft_file = get_graft_file();
 215         read_graft_file(graft_file);
 216         /* make sure shallows are read */
 217         is_repository_shallow();
 218         commit_graft_prepared = 1;
 219 }
 220
 221 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 222 {
 223         int pos;
 224         prepare_commit_graft();
 225         pos = commit_graft_pos(sha1);
 226         if (pos < 0)
 227                 return NULL;
 228         return commit_graft[pos];
 229 }
 230
 231 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 232 {
 233         int i, ret;
 234         for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 235                 ret = fn(commit_graft[i], cb_data);
 236         return ret;
 237 }
 238
 239 int unregister_shallow(const unsigned char *sha1)
 240 {
 241         int pos = commit_graft_pos(sha1);
 242         if (pos < 0)
 243                 return -1;
 244         if (pos + 1 < commit_graft_nr)
 245                 memmove(commit_graft + pos, commit_graft + pos + 1,
 246                                 sizeof(struct commit_graft *)
 247                                 * (commit_graft_nr - pos - 1));
 248         commit_graft_nr--;
 249         return 0;
 250 }
 251
 252 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 253 {
 254         const char *tail = buffer;
 255         const char *bufptr = buffer;
 256         unsigned char parent[20];
 257         struct commit_list **pptr;
 258         struct commit_graft *graft;
 259
 260         if (item->object.parsed)
 261                 return 0;
 262         item->object.parsed = 1;
 263         tail += size;
 264         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 265                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 266         if (get_sha1_hex(bufptr + 5, parent) < 0)
 267                 return error("bad tree pointer in commit %s",
 268                              sha1_to_hex(item->object.sha1));
 269         item->tree = lookup_tree(parent);
 270         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 271         pptr = &item->parents;
 272
 273         graft = lookup_commit_graft(item->object.sha1);
 274         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 275                 struct commit *new_parent;
 276
 277                 if (tail <= bufptr + 48 ||
 278                     get_sha1_hex(bufptr + 7, parent) ||
 279                     bufptr[47] != '\n')
 280                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 281                 bufptr += 48;
 282                 /*
 283                  * The clone is shallow if nr_parent < 0, and we must
 284                  * not traverse its real parents even when we unhide them.
 285                  */
 286                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 287                         continue;
 288                 new_parent = lookup_commit(parent);
 289                 if (new_parent)
 290                         pptr = &commit_list_insert(new_parent, pptr)->next;
 291         }
 292         if (graft) {
 293                 int i;
 294                 struct commit *new_parent;
 295                 for (i = 0; i < graft->nr_parent; i++) {
 296                         new_parent = lookup_commit(graft->parent[i]);
 297                         if (!new_parent)
 298                                 continue;
 299                         pptr = &commit_list_insert(new_parent, pptr)->next;
 300                 }
 301         }
 302         item->date = parse_commit_date(bufptr, tail);
 303
 304         return 0;
 305 }
 306
 307 int parse_commit(struct commit *item)
 308 {
 309         enum object_type type;
 310         void *buffer;
 311         unsigned long size;
 312         int ret;
 313
 314         if (!item)
 315                 return -1;
 316         if (item->object.parsed)
 317                 return 0;
 318         buffer = read_sha1_file(item->object.sha1, &type, &size);
 319         if (!buffer)
 320                 return error("Could not read %s",
 321                              sha1_to_hex(item->object.sha1));
 322         if (type != OBJ_COMMIT) {
 323                 free(buffer);
 324                 return error("Object %s not a commit",
 325                              sha1_to_hex(item->object.sha1));
 326         }
 327         ret = parse_commit_buffer(item, buffer, size);
 328         if (save_commit_buffer && !ret) {
 329                 item->buffer = buffer;
 330                 return 0;
 331         }
 332         free(buffer);
 333         return ret;
 334 }
 335
 336 int find_commit_subject(const char *commit_buffer, const char **subject)
 337 {
 338         const char *eol;
 339         const char *p = commit_buffer;
 340
 341         while (*p && (*p != '\n' || p[1] != '\n'))
 342                 p++;
 343         if (*p) {
 344                 p += 2;
 345                 for (eol = p; *eol && *eol != '\n'; eol++)
 346                         ; /* do nothing */
 347         } else
 348                 eol = p;
 349
 350         *subject = p;
 351
 352         return eol - p;
 353 }
 354
 355 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 356 {
 357         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 358         new_list->item = item;
 359         new_list->next = *list_p;
 360         *list_p = new_list;
 361         return new_list;
 362 }
 363
 364 void commit_list_reverse(struct commit_list **list_p)
 365 {
 366         struct commit_list *prev = NULL, *curr = *list_p, *next;
 367
 368         if (!list_p)
 369                 return;
 370         while (curr) {
 371                 next = curr->next;
 372                 curr->next = prev;
 373                 prev = curr;
 374                 curr = next;
 375         }
 376         *list_p = prev;
 377 }
 378
 379 unsigned commit_list_count(const struct commit_list *l)
 380 {
 381         unsigned c = 0;
 382         for (; l; l = l->next )
 383                 c++;
 384         return c;
 385 }
 386
 387 void free_commit_list(struct commit_list *list)
 388 {
 389         while (list) {
 390                 struct commit_list *temp = list;
 391                 list = temp->next;
 392                 free(temp);
 393         }
 394 }
 395
 396 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 397 {
 398         struct commit_list **pp = list;
 399         struct commit_list *p;
 400         while ((p = *pp) != NULL) {
 401                 if (p->item->date < item->date) {
 402                         break;
 403                 }
 404                 pp = &p->next;
 405         }
 406         return commit_list_insert(item, pp);
 407 }
 408
 409 static int commit_list_compare_by_date(const void *a, const void *b)
 410 {
 411         unsigned long a_date = ((const struct commit_list *)a)->item->date;
 412         unsigned long b_date = ((const struct commit_list *)b)->item->date;
 413         if (a_date < b_date)
 414                 return 1;
 415         if (a_date > b_date)
 416                 return -1;
 417         return 0;
 418 }
 419
 420 static void *commit_list_get_next(const void *a)
 421 {
 422         return ((const struct commit_list *)a)->next;
 423 }
 424
 425 static void commit_list_set_next(void *a, void *next)
 426 {
 427         ((struct commit_list *)a)->next = next;
 428 }
 429
 430 void commit_list_sort_by_date(struct commit_list **list)
 431 {
 432         *list = mergesort(*list, commit_list_get_next, commit_list_set_next,
 433                           commit_list_compare_by_date);
 434 }
 435
 436 struct commit *pop_most_recent_commit(struct commit_list **list,
 437                                       unsigned int mark)
 438 {
 439         struct commit *ret = (*list)->item;
 440         struct commit_list *parents = ret->parents;
 441         struct commit_list *old = *list;
 442
 443         *list = (*list)->next;
 444         free(old);
 445
 446         while (parents) {
 447                 struct commit *commit = parents->item;
 448                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 449                         commit->object.flags |= mark;
 450                         commit_list_insert_by_date(commit, list);
 451                 }
 452                 parents = parents->next;
 453         }
 454         return ret;
 455 }
 456
 457 void clear_commit_marks(struct commit *commit, unsigned int mark)
 458 {
 459         while (commit) {
 460                 struct commit_list *parents;
 461
 462                 if (!(mark & commit->object.flags))
 463                         return;
 464
 465                 commit->object.flags &= ~mark;
 466
 467                 parents = commit->parents;
 468                 if (!parents)
 469                         return;
 470
 471                 while ((parents = parents->next))
 472                         clear_commit_marks(parents->item, mark);
 473
 474                 commit = commit->parents->item;
 475         }
 476 }
 477
 478 void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 479 {
 480         struct object *object;
 481         struct commit *commit;
 482         unsigned int i;
 483
 484         for (i = 0; i < a->nr; i++) {
 485                 object = a->objects[i].item;
 486                 commit = lookup_commit_reference_gently(object->sha1, 1);
 487                 if (commit)
 488                         clear_commit_marks(commit, mark);
 489         }
 490 }
 491
 492 struct commit *pop_commit(struct commit_list **stack)
 493 {
 494         struct commit_list *top = *stack;
 495         struct commit *item = top ? top->item : NULL;
 496
 497         if (top) {
 498                 *stack = top->next;
 499                 free(top);
 500         }
 501         return item;
 502 }
 503
 504 /*
 505  * Performs an in-place topological sort on the list supplied.
 506  */
 507 void sort_in_topological_order(struct commit_list ** list, int lifo)
 508 {
 509         struct commit_list *next, *orig = *list;
 510         struct commit_list *work, **insert;
 511         struct commit_list **pptr;
 512
 513         if (!orig)
 514                 return;
 515         *list = NULL;
 516
 517         /* Mark them and clear the indegree */
 518         for (next = orig; next; next = next->next) {
 519                 struct commit *commit = next->item;
 520                 commit->indegree = 1;
 521         }
 522
 523         /* update the indegree */
 524         for (next = orig; next; next = next->next) {
 525                 struct commit_list * parents = next->item->parents;
 526                 while (parents) {
 527                         struct commit *parent = parents->item;
 528
 529                         if (parent->indegree)
 530                                 parent->indegree++;
 531                         parents = parents->next;
 532                 }
 533         }
 534
 535         /*
 536          * find the tips
 537          *
 538          * tips are nodes not reachable from any other node in the list
 539          *
 540          * the tips serve as a starting set for the work queue.
 541          */
 542         work = NULL;
 543         insert = &work;
 544         for (next = orig; next; next = next->next) {
 545                 struct commit *commit = next->item;
 546
 547                 if (commit->indegree == 1)
 548                         insert = &commit_list_insert(commit, insert)->next;
 549         }
 550
 551         /* process the list in topological order */
 552         if (!lifo)
 553                 commit_list_sort_by_date(&work);
 554
 555         pptr = list;
 556         *list = NULL;
 557         while (work) {
 558                 struct commit *commit;
 559                 struct commit_list *parents, *work_item;
 560
 561                 work_item = work;
 562                 work = work_item->next;
 563                 work_item->next = NULL;
 564
 565                 commit = work_item->item;
 566                 for (parents = commit->parents; parents ; parents = parents->next) {
 567                         struct commit *parent = parents->item;
 568
 569                         if (!parent->indegree)
 570                                 continue;
 571
 572                         /*
 573                          * parents are only enqueued for emission
 574                          * when all their children have been emitted thereby
 575                          * guaranteeing topological order.
 576                          */
 577                         if (--parent->indegree == 1) {
 578                                 if (!lifo)
 579                                         commit_list_insert_by_date(parent, &work);
 580                                 else
 581                                         commit_list_insert(parent, &work);
 582                         }
 583                 }
 584                 /*
 585                  * work_item is a commit all of whose children
 586                  * have already been emitted. we can emit it now.
 587                  */
 588                 commit->indegree = 0;
 589                 *pptr = work_item;
 590                 pptr = &work_item->next;
 591         }
 592 }
 593
 594 /* merge-base stuff */
 595
 596 /* bits #0..15 in revision.h */
 597 #define PARENT1         (1u<<16)
 598 #define PARENT2         (1u<<17)
 599 #define STALE           (1u<<18)
 600 #define RESULT          (1u<<19)
 601
 602 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 603
 604 static struct commit *interesting(struct commit_list *list)
 605 {
 606         while (list) {
 607                 struct commit *commit = list->item;
 608                 list = list->next;
 609                 if (commit->object.flags & STALE)
 610                         continue;
 611                 return commit;
 612         }
 613         return NULL;
 614 }
 615
 616 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 617 {
 618         struct commit_list *list = NULL;
 619         struct commit_list *result = NULL;
 620         int i;
 621
 622         for (i = 0; i < n; i++) {
 623                 if (one == twos[i])
 624                         /*
 625                          * We do not mark this even with RESULT so we do not
 626                          * have to clean it up.
 627                          */
 628                         return commit_list_insert(one, &result);
 629         }
 630
 631         if (parse_commit(one))
 632                 return NULL;
 633         for (i = 0; i < n; i++) {
 634                 if (parse_commit(twos[i]))
 635                         return NULL;
 636         }
 637
 638         one->object.flags |= PARENT1;
 639         commit_list_insert_by_date(one, &list);
 640         for (i = 0; i < n; i++) {
 641                 twos[i]->object.flags |= PARENT2;
 642                 commit_list_insert_by_date(twos[i], &list);
 643         }
 644
 645         while (interesting(list)) {
 646                 struct commit *commit;
 647                 struct commit_list *parents;
 648                 struct commit_list *next;
 649                 int flags;
 650
 651                 commit = list->item;
 652                 next = list->next;
 653                 free(list);
 654                 list = next;
 655
 656                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 657                 if (flags == (PARENT1 | PARENT2)) {
 658                         if (!(commit->object.flags & RESULT)) {
 659                                 commit->object.flags |= RESULT;
 660                                 commit_list_insert_by_date(commit, &result);
 661                         }
 662                         /* Mark parents of a found merge stale */
 663                         flags |= STALE;
 664                 }
 665                 parents = commit->parents;
 666                 while (parents) {
 667                         struct commit *p = parents->item;
 668                         parents = parents->next;
 669                         if ((p->object.flags & flags) == flags)
 670                                 continue;
 671                         if (parse_commit(p))
 672                                 return NULL;
 673                         p->object.flags |= flags;
 674                         commit_list_insert_by_date(p, &list);
 675                 }
 676         }
 677
 678         /* Clean up the result to remove stale ones */
 679         free_commit_list(list);
 680         list = result; result = NULL;
 681         while (list) {
 682                 struct commit_list *next = list->next;
 683                 if (!(list->item->object.flags & STALE))
 684                         commit_list_insert_by_date(list->item, &result);
 685                 free(list);
 686                 list = next;
 687         }
 688         return result;
 689 }
 690
 691 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 692 {
 693         struct commit_list *i, *j, *k, *ret = NULL;
 694         struct commit_list **pptr = &ret;
 695
 696         for (i = in; i; i = i->next) {
 697                 if (!ret)
 698                         pptr = &commit_list_insert(i->item, pptr)->next;
 699                 else {
 700                         struct commit_list *new = NULL, *end = NULL;
 701
 702                         for (j = ret; j; j = j->next) {
 703                                 struct commit_list *bases;
 704                                 bases = get_merge_bases(i->item, j->item, 1);
 705                                 if (!new)
 706                                         new = bases;
 707                                 else
 708                                         end->next = bases;
 709                                 for (k = bases; k; k = k->next)
 710                                         end = k;
 711                         }
 712                         ret = new;
 713                 }
 714         }
 715         return ret;
 716 }
 717
 718 struct commit_list *get_merge_bases_many(struct commit *one,
 719                                          int n,
 720                                          struct commit **twos,
 721                                          int cleanup)
 722 {
 723         struct commit_list *list;
 724         struct commit **rslt;
 725         struct commit_list *result;
 726         int cnt, i, j;
 727
 728         result = merge_bases_many(one, n, twos);
 729         for (i = 0; i < n; i++) {
 730                 if (one == twos[i])
 731                         return result;
 732         }
 733         if (!result || !result->next) {
 734                 if (cleanup) {
 735                         clear_commit_marks(one, all_flags);
 736                         for (i = 0; i < n; i++)
 737                                 clear_commit_marks(twos[i], all_flags);
 738                 }
 739                 return result;
 740         }
 741
 742         /* There are more than one */
 743         cnt = 0;
 744         list = result;
 745         while (list) {
 746                 list = list->next;
 747                 cnt++;
 748         }
 749         rslt = xcalloc(cnt, sizeof(*rslt));
 750         for (list = result, i = 0; list; list = list->next)
 751                 rslt[i++] = list->item;
 752         free_commit_list(result);
 753
 754         clear_commit_marks(one, all_flags);
 755         for (i = 0; i < n; i++)
 756                 clear_commit_marks(twos[i], all_flags);
 757         for (i = 0; i < cnt - 1; i++) {
 758                 for (j = i+1; j < cnt; j++) {
 759                         if (!rslt[i] || !rslt[j])
 760                                 continue;
 761                         result = merge_bases_many(rslt[i], 1, &rslt[j]);
 762                         clear_commit_marks(rslt[i], all_flags);
 763                         clear_commit_marks(rslt[j], all_flags);
 764                         for (list = result; list; list = list->next) {
 765                                 if (rslt[i] == list->item)
 766                                         rslt[i] = NULL;
 767                                 if (rslt[j] == list->item)
 768                                         rslt[j] = NULL;
 769                         }
 770                 }
 771         }
 772
 773         /* Surviving ones in rslt[] are the independent results */
 774         result = NULL;
 775         for (i = 0; i < cnt; i++) {
 776                 if (rslt[i])
 777                         commit_list_insert_by_date(rslt[i], &result);
 778         }
 779         free(rslt);
 780         return result;
 781 }
 782
 783 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 784                                     int cleanup)
 785 {
 786         return get_merge_bases_many(one, 1, &two, cleanup);
 787 }
 788
 789 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 790 {
 791         if (!with_commit)
 792                 return 1;
 793         while (with_commit) {
 794                 struct commit *other;
 795
 796                 other = with_commit->item;
 797                 with_commit = with_commit->next;
 798                 if (in_merge_bases(other, &commit, 1))
 799                         return 1;
 800         }
 801         return 0;
 802 }
 803
 804 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 805 {
 806         struct commit_list *bases, *b;
 807         int ret = 0;
 808
 809         if (num == 1)
 810                 bases = get_merge_bases(commit, *reference, 1);
 811         else
 812                 die("not yet");
 813         for (b = bases; b; b = b->next) {
 814                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 815                         ret = 1;
 816                         break;
 817                 }
 818         }
 819
 820         free_commit_list(bases);
 821         return ret;
 822 }
 823
 824 struct commit_list *reduce_heads(struct commit_list *heads)
 825 {
 826         struct commit_list *p;
 827         struct commit_list *result = NULL, **tail = &result;
 828         struct commit **other;
 829         size_t num_head, num_other;
 830
 831         if (!heads)
 832                 return NULL;
 833
 834         /* Avoid unnecessary reallocations */
 835         for (p = heads, num_head = 0; p; p = p->next)
 836                 num_head++;
 837         other = xcalloc(sizeof(*other), num_head);
 838
 839         /* For each commit, see if it can be reached by others */
 840         for (p = heads; p; p = p->next) {
 841                 struct commit_list *q, *base;
 842
 843                 /* Do we already have this in the result? */
 844                 for (q = result; q; q = q->next)
 845                         if (p->item == q->item)
 846                                 break;
 847                 if (q)
 848                         continue;
 849
 850                 num_other = 0;
 851                 for (q = heads; q; q = q->next) {
 852                         if (p->item == q->item)
 853                                 continue;
 854                         other[num_other++] = q->item;
 855                 }
 856                 if (num_other)
 857                         base = get_merge_bases_many(p->item, num_other, other, 1);
 858                 else
 859                         base = NULL;
 860                 /*
 861                  * If p->item does not have anything common with other
 862                  * commits, there won't be any merge base.  If it is
 863                  * reachable from some of the others, p->item will be
 864                  * the merge base.  If its history is connected with
 865                  * others, but p->item is not reachable by others, we
 866                  * will get something other than p->item back.
 867                  */
 868                 if (!base || (base->item != p->item))
 869                         tail = &(commit_list_insert(p->item, tail)->next);
 870                 free_commit_list(base);
 871         }
 872         free(other);
 873         return result;
 874 }
 875
 876 static const char gpg_sig_header[] = "gpgsig";
 877 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 878
 879 static int do_sign_commit(struct strbuf *buf, const char *keyid)
 880 {
 881         struct strbuf sig = STRBUF_INIT;
 882         int inspos, copypos;
 883
 884         /* find the end of the header */
 885         inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
 886
 887         if (!keyid || !*keyid)
 888                 keyid = get_signing_key();
 889         if (sign_buffer(buf, &sig, keyid)) {
 890                 strbuf_release(&sig);
 891                 return -1;
 892         }
 893
 894         for (copypos = 0; sig.buf[copypos]; ) {
 895                 const char *bol = sig.buf + copypos;
 896                 const char *eol = strchrnul(bol, '\n');
 897                 int len = (eol - bol) + !!*eol;
 898
 899                 if (!copypos) {
 900                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 901                         inspos += gpg_sig_header_len;
 902                 }
 903                 strbuf_insert(buf, inspos++, " ", 1);
 904                 strbuf_insert(buf, inspos, bol, len);
 905                 inspos += len;
 906                 copypos += len;
 907         }
 908         strbuf_release(&sig);
 909         return 0;
 910 }
 911
 912 int parse_signed_commit(const unsigned char *sha1,
 913                         struct strbuf *payload, struct strbuf *signature)
 914 {
 915         unsigned long size;
 916         enum object_type type;
 917         char *buffer = read_sha1_file(sha1, &type, &size);
 918         int in_signature, saw_signature = -1;
 919         char *line, *tail;
 920
 921         if (!buffer || type != OBJ_COMMIT)
 922                 goto cleanup;
 923
 924         line = buffer;
 925         tail = buffer + size;
 926         in_signature = 0;
 927         saw_signature = 0;
 928         while (line < tail) {
 929                 const char *sig = NULL;
 930                 char *next = memchr(line, '\n', tail - line);
 931
 932                 next = next ? next + 1 : tail;
 933                 if (in_signature && line[0] == ' ')
 934                         sig = line + 1;
 935                 else if (!prefixcmp(line, gpg_sig_header) &&
 936                          line[gpg_sig_header_len] == ' ')
 937                         sig = line + gpg_sig_header_len + 1;
 938                 if (sig) {
 939                         strbuf_add(signature, sig, next - sig);
 940                         saw_signature = 1;
 941                         in_signature = 1;
 942                 } else {
 943                         if (*line == '\n')
 944                                 /* dump the whole remainder of the buffer */
 945                                 next = tail;
 946                         strbuf_add(payload, line, next - line);
 947                         in_signature = 0;
 948                 }
 949                 line = next;
 950         }
 951  cleanup:
 952         free(buffer);
 953         return saw_signature;
 954 }
 955
 956 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 957 {
 958         struct merge_remote_desc *desc;
 959         struct commit_extra_header *mergetag;
 960         char *buf;
 961         unsigned long size, len;
 962         enum object_type type;
 963
 964         desc = merge_remote_util(parent);
 965         if (!desc || !desc->obj)
 966                 return;
 967         buf = read_sha1_file(desc->obj->sha1, &type, &size);
 968         if (!buf || type != OBJ_TAG)
 969                 goto free_return;
 970         len = parse_signature(buf, size);
 971         if (size == len)
 972                 goto free_return;
 973         /*
 974          * We could verify this signature and either omit the tag when
 975          * it does not validate, but the integrator may not have the
 976          * public key of the signer of the tag he is merging, while a
 977          * later auditor may have it while auditing, so let's not run
 978          * verify-signed-buffer here for now...
 979          *
 980          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
 981          *      warn("warning: signed tag unverified.");
 982          */
 983         mergetag = xcalloc(1, sizeof(*mergetag));
 984         mergetag->key = xstrdup("mergetag");
 985         mergetag->value = buf;
 986         mergetag->len = size;
 987
 988         **tail = mergetag;
 989         *tail = &mergetag->next;
 990         return;
 991
 992 free_return:
 993         free(buf);
 994 }
 995
 996 void append_merge_tag_headers(struct commit_list *parents,
 997                               struct commit_extra_header ***tail)
 998 {
 999         while (parents) {
1000                 struct commit *parent = parents->item;
1001                 handle_signed_tag(parent, tail);
1002                 parents = parents->next;
1003         }
1004 }
1005
1006 static void add_extra_header(struct strbuf *buffer,
1007                              struct commit_extra_header *extra)
1008 {
1009         strbuf_addstr(buffer, extra->key);
1010         if (extra->len)
1011                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1012         else
1013                 strbuf_addch(buffer, '\n');
1014 }
1015
1016 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1017                                                       const char **exclude)
1018 {
1019         struct commit_extra_header *extra = NULL;
1020         unsigned long size;
1021         enum object_type type;
1022         char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1023         if (buffer && type == OBJ_COMMIT)
1024                 extra = read_commit_extra_header_lines(buffer, size, exclude);
1025         free(buffer);
1026         return extra;
1027 }
1028
1029 static inline int standard_header_field(const char *field, size_t len)
1030 {
1031         return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1032                 (len == 6 && !memcmp(field, "parent ", 7)) ||
1033                 (len == 6 && !memcmp(field, "author ", 7)) ||
1034                 (len == 9 && !memcmp(field, "committer ", 10)) ||
1035                 (len == 8 && !memcmp(field, "encoding ", 9)));
1036 }
1037
1038 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1039 {
1040         if (!exclude)
1041                 return 0;
1042
1043         while (*exclude) {
1044                 size_t xlen = strlen(*exclude);
1045                 if (len == xlen &&
1046                     !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1047                         return 1;
1048                 exclude++;
1049         }
1050         return 0;
1051 }
1052
1053 struct commit_extra_header *read_commit_extra_header_lines(const char *buffer, size_t size,
1054                                                            const char **exclude)
1055 {
1056         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1057         const char *line, *next, *eof, *eob;
1058         struct strbuf buf = STRBUF_INIT;
1059
1060         for (line = buffer, eob = line + size;
1061              line < eob && *line != '\n';
1062              line = next) {
1063                 next = memchr(line, '\n', eob - line);
1064                 next = next ? next + 1 : eob;
1065                 if (*line == ' ') {
1066                         /* continuation */
1067                         if (it)
1068                                 strbuf_add(&buf, line + 1, next - (line + 1));
1069                         continue;
1070                 }
1071                 if (it)
1072                         it->value = strbuf_detach(&buf, &it->len);
1073                 strbuf_reset(&buf);
1074                 it = NULL;
1075
1076                 eof = strchr(line, ' ');
1077                 if (next <= eof)
1078                         eof = next;
1079
1080                 if (standard_header_field(line, eof - line) ||
1081                     excluded_header_field(line, eof - line, exclude))
1082                         continue;
1083
1084                 it = xcalloc(1, sizeof(*it));
1085                 it->key = xmemdupz(line, eof-line);
1086                 *tail = it;
1087                 tail = &it->next;
1088                 if (eof + 1 < next)
1089                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1090         }
1091         if (it)
1092                 it->value = strbuf_detach(&buf, &it->len);
1093         return extra;
1094 }
1095
1096 void free_commit_extra_headers(struct commit_extra_header *extra)
1097 {
1098         while (extra) {
1099                 struct commit_extra_header *next = extra->next;
1100                 free(extra->key);
1101                 free(extra->value);
1102                 free(extra);
1103                 extra = next;
1104         }
1105 }
1106
1107 int commit_tree(const struct strbuf *msg, unsigned char *tree,
1108                 struct commit_list *parents, unsigned char *ret,
1109                 const char *author, const char *sign_commit)
1110 {
1111         struct commit_extra_header *extra = NULL, **tail = &extra;
1112         int result;
1113
1114         append_merge_tag_headers(parents, &tail);
1115         result = commit_tree_extended(msg, tree, parents, ret,
1116                                       author, sign_commit, extra);
1117         free_commit_extra_headers(extra);
1118         return result;
1119 }
1120
1121 static const char commit_utf8_warn[] =
1122 "Warning: commit message does not conform to UTF-8.\n"
1123 "You may want to amend it after fixing the message, or set the config\n"
1124 "variable i18n.commitencoding to the encoding your project uses.\n";
1125
1126 int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1127                          struct commit_list *parents, unsigned char *ret,
1128                          const char *author, const char *sign_commit,
1129                          struct commit_extra_header *extra)
1130 {
1131         int result;
1132         int encoding_is_utf8;
1133         struct strbuf buffer;
1134
1135         assert_sha1_type(tree, OBJ_TREE);
1136
1137         if (memchr(msg->buf, '\0', msg->len))
1138                 return error("a NUL byte in commit log message not allowed.");
1139
1140         /* Not having i18n.commitencoding is the same as having utf-8 */
1141         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1142
1143         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1144         strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1145
1146         /*
1147          * NOTE! This ordering means that the same exact tree merged with a
1148          * different order of parents will be a _different_ changeset even
1149          * if everything else stays the same.
1150          */
1151         while (parents) {
1152                 struct commit_list *next = parents->next;
1153                 struct commit *parent = parents->item;
1154
1155                 strbuf_addf(&buffer, "parent %s\n",
1156                             sha1_to_hex(parent->object.sha1));
1157                 free(parents);
1158                 parents = next;
1159         }
1160
1161         /* Person/date information */
1162         if (!author)
1163                 author = git_author_info(IDENT_ERROR_ON_NO_NAME);
1164         strbuf_addf(&buffer, "author %s\n", author);
1165         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_ERROR_ON_NO_NAME));
1166         if (!encoding_is_utf8)
1167                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1168
1169         while (extra) {
1170                 add_extra_header(&buffer, extra);
1171                 extra = extra->next;
1172         }
1173         strbuf_addch(&buffer, '\n');
1174
1175         /* And add the comment */
1176         strbuf_addbuf(&buffer, msg);
1177
1178         /* And check the encoding */
1179         if (encoding_is_utf8 && !is_utf8(buffer.buf))
1180                 fprintf(stderr, commit_utf8_warn);
1181
1182         if (sign_commit && do_sign_commit(&buffer, sign_commit))
1183                 return -1;
1184
1185         result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1186         strbuf_release(&buffer);
1187         return result;
1188 }
1189
1190 struct commit *get_merge_parent(const char *name)
1191 {
1192         struct object *obj;
1193         struct commit *commit;
1194         unsigned char sha1[20];
1195         if (get_sha1(name, sha1))
1196                 return NULL;
1197         obj = parse_object(sha1);
1198         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1199         if (commit && !commit->util) {
1200                 struct merge_remote_desc *desc;
1201                 desc = xmalloc(sizeof(*desc));
1202                 desc->obj = obj;
1203                 desc->name = strdup(name);
1204                 commit->util = desc;
1205         }
1206         return commit;
1207 }