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
   9 int save_commit_buffer = 1;
  10
  11 const char *commit_type = "commit";
  12
  13 static struct commit *check_commit(struct object *obj,
  14                                    const unsigned char *sha1,
  15                                    int quiet)
  16 {
  17         if (obj->type != OBJ_COMMIT) {
  18                 if (!quiet)
  19                         error("Object %s is a %s, not a commit",
  20                               sha1_to_hex(sha1), typename(obj->type));
  21                 return NULL;
  22         }
  23         return (struct commit *) obj;
  24 }
  25
  26 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  27                                               int quiet)
  28 {
  29         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  30
  31         if (!obj)
  32                 return NULL;
  33         return check_commit(obj, sha1, quiet);
  34 }
  35
  36 struct commit *lookup_commit_reference(const unsigned char *sha1)
  37 {
  38         return lookup_commit_reference_gently(sha1, 0);
  39 }
  40
  41 struct commit *lookup_commit(const unsigned char *sha1)
  42 {
  43         struct object *obj = lookup_object(sha1);
  44         if (!obj)
  45                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  46         if (!obj->type)
  47                 obj->type = OBJ_COMMIT;
  48         return check_commit(obj, sha1, 0);
  49 }
  50
  51 static unsigned long parse_commit_date(const char *buf)
  52 {
  53         unsigned long date;
  54
  55         if (memcmp(buf, "author", 6))
  56                 return 0;
  57         while (*buf++ != '\n')
  58                 /* nada */;
  59         if (memcmp(buf, "committer", 9))
  60                 return 0;
  61         while (*buf++ != '>')
  62                 /* nada */;
  63         date = strtoul(buf, NULL, 10);
  64         if (date == ULONG_MAX)
  65                 date = 0;
  66         return date;
  67 }
  68
  69 static struct commit_graft **commit_graft;
  70 static int commit_graft_alloc, commit_graft_nr;
  71
  72 static int commit_graft_pos(const unsigned char *sha1)
  73 {
  74         int lo, hi;
  75         lo = 0;
  76         hi = commit_graft_nr;
  77         while (lo < hi) {
  78                 int mi = (lo + hi) / 2;
  79                 struct commit_graft *graft = commit_graft[mi];
  80                 int cmp = hashcmp(sha1, graft->sha1);
  81                 if (!cmp)
  82                         return mi;
  83                 if (cmp < 0)
  84                         hi = mi;
  85                 else
  86                         lo = mi + 1;
  87         }
  88         return -lo - 1;
  89 }
  90
  91 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
  92 {
  93         int pos = commit_graft_pos(graft->sha1);
  94
  95         if (0 <= pos) {
  96                 if (ignore_dups)
  97                         free(graft);
  98                 else {
  99                         free(commit_graft[pos]);
 100                         commit_graft[pos] = graft;
 101                 }
 102                 return 1;
 103         }
 104         pos = -pos - 1;
 105         if (commit_graft_alloc <= ++commit_graft_nr) {
 106                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 107                 commit_graft = xrealloc(commit_graft,
 108                                         sizeof(*commit_graft) *
 109                                         commit_graft_alloc);
 110         }
 111         if (pos < commit_graft_nr)
 112                 memmove(commit_graft + pos + 1,
 113                         commit_graft + pos,
 114                         (commit_graft_nr - pos - 1) *
 115                         sizeof(*commit_graft));
 116         commit_graft[pos] = graft;
 117         return 0;
 118 }
 119
 120 struct commit_graft *read_graft_line(char *buf, int len)
 121 {
 122         /* The format is just "Commit Parent1 Parent2 ...\n" */
 123         int i;
 124         struct commit_graft *graft = NULL;
 125
 126         if (buf[len-1] == '\n')
 127                 buf[--len] = 0;
 128         if (buf[0] == '#' || buf[0] == '\0')
 129                 return NULL;
 130         if ((len + 1) % 41) {
 131         bad_graft_data:
 132                 error("bad graft data: %s", buf);
 133                 free(graft);
 134                 return NULL;
 135         }
 136         i = (len + 1) / 41 - 1;
 137         graft = xmalloc(sizeof(*graft) + 20 * i);
 138         graft->nr_parent = i;
 139         if (get_sha1_hex(buf, graft->sha1))
 140                 goto bad_graft_data;
 141         for (i = 40; i < len; i += 41) {
 142                 if (buf[i] != ' ')
 143                         goto bad_graft_data;
 144                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 145                         goto bad_graft_data;
 146         }
 147         return graft;
 148 }
 149
 150 int read_graft_file(const char *graft_file)
 151 {
 152         FILE *fp = fopen(graft_file, "r");
 153         char buf[1024];
 154         if (!fp)
 155                 return -1;
 156         while (fgets(buf, sizeof(buf), fp)) {
 157                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 158                 int len = strlen(buf);
 159                 struct commit_graft *graft = read_graft_line(buf, len);
 160                 if (!graft)
 161                         continue;
 162                 if (register_commit_graft(graft, 1))
 163                         error("duplicate graft data: %s", buf);
 164         }
 165         fclose(fp);
 166         return 0;
 167 }
 168
 169 static void prepare_commit_graft(void)
 170 {
 171         static int commit_graft_prepared;
 172         char *graft_file;
 173
 174         if (commit_graft_prepared)
 175                 return;
 176         graft_file = get_graft_file();
 177         read_graft_file(graft_file);
 178         /* make sure shallows are read */
 179         is_repository_shallow();
 180         commit_graft_prepared = 1;
 181 }
 182
 183 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 184 {
 185         int pos;
 186         prepare_commit_graft();
 187         pos = commit_graft_pos(sha1);
 188         if (pos < 0)
 189                 return NULL;
 190         return commit_graft[pos];
 191 }
 192
 193 int write_shallow_commits(int fd, int use_pack_protocol)
 194 {
 195         int i, count = 0;
 196         for (i = 0; i < commit_graft_nr; i++)
 197                 if (commit_graft[i]->nr_parent < 0) {
 198                         const char *hex =
 199                                 sha1_to_hex(commit_graft[i]->sha1);
 200                         count++;
 201                         if (use_pack_protocol)
 202                                 packet_write(fd, "shallow %s", hex);
 203                         else {
 204                                 if (write_in_full(fd, hex,  40) != 40)
 205                                         break;
 206                                 if (write_in_full(fd, "\n", 1) != 1)
 207                                         break;
 208                         }
 209                 }
 210         return count;
 211 }
 212
 213 int unregister_shallow(const unsigned char *sha1)
 214 {
 215         int pos = commit_graft_pos(sha1);
 216         if (pos < 0)
 217                 return -1;
 218         if (pos + 1 < commit_graft_nr)
 219                 memcpy(commit_graft + pos, commit_graft + pos + 1,
 220                                 sizeof(struct commit_graft *)
 221                                 * (commit_graft_nr - pos - 1));
 222         commit_graft_nr--;
 223         return 0;
 224 }
 225
 226 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 227 {
 228         char *tail = buffer;
 229         char *bufptr = buffer;
 230         unsigned char parent[20];
 231         struct commit_list **pptr;
 232         struct commit_graft *graft;
 233         unsigned n_refs = 0;
 234
 235         if (item->object.parsed)
 236                 return 0;
 237         item->object.parsed = 1;
 238         tail += size;
 239         if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 240                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 241         if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 242                 return error("bad tree pointer in commit %s",
 243                              sha1_to_hex(item->object.sha1));
 244         item->tree = lookup_tree(parent);
 245         if (item->tree)
 246                 n_refs++;
 247         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 248         pptr = &item->parents;
 249
 250         graft = lookup_commit_graft(item->object.sha1);
 251         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 252                 struct commit *new_parent;
 253
 254                 if (tail <= bufptr + 48 ||
 255                     get_sha1_hex(bufptr + 7, parent) ||
 256                     bufptr[47] != '\n')
 257                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 258                 bufptr += 48;
 259                 if (graft)
 260                         continue;
 261                 new_parent = lookup_commit(parent);
 262                 if (new_parent) {
 263                         pptr = &commit_list_insert(new_parent, pptr)->next;
 264                         n_refs++;
 265                 }
 266         }
 267         if (graft) {
 268                 int i;
 269                 struct commit *new_parent;
 270                 for (i = 0; i < graft->nr_parent; i++) {
 271                         new_parent = lookup_commit(graft->parent[i]);
 272                         if (!new_parent)
 273                                 continue;
 274                         pptr = &commit_list_insert(new_parent, pptr)->next;
 275                         n_refs++;
 276                 }
 277         }
 278         item->date = parse_commit_date(bufptr);
 279
 280         if (track_object_refs) {
 281                 unsigned i = 0;
 282                 struct commit_list *p;
 283                 struct object_refs *refs = alloc_object_refs(n_refs);
 284                 if (item->tree)
 285                         refs->ref[i++] = &item->tree->object;
 286                 for (p = item->parents; p; p = p->next)
 287                         refs->ref[i++] = &p->item->object;
 288                 set_object_refs(&item->object, refs);
 289         }
 290
 291         return 0;
 292 }
 293
 294 int parse_commit(struct commit *item)
 295 {
 296         enum object_type type;
 297         void *buffer;
 298         unsigned long size;
 299         int ret;
 300
 301         if (item->object.parsed)
 302                 return 0;
 303         buffer = read_sha1_file(item->object.sha1, &type, &size);
 304         if (!buffer)
 305                 return error("Could not read %s",
 306                              sha1_to_hex(item->object.sha1));
 307         if (type != OBJ_COMMIT) {
 308                 free(buffer);
 309                 return error("Object %s not a commit",
 310                              sha1_to_hex(item->object.sha1));
 311         }
 312         ret = parse_commit_buffer(item, buffer, size);
 313         if (save_commit_buffer && !ret) {
 314                 item->buffer = buffer;
 315                 return 0;
 316         }
 317         free(buffer);
 318         return ret;
 319 }
 320
 321 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 322 {
 323         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 324         new_list->item = item;
 325         new_list->next = *list_p;
 326         *list_p = new_list;
 327         return new_list;
 328 }
 329
 330 void free_commit_list(struct commit_list *list)
 331 {
 332         while (list) {
 333                 struct commit_list *temp = list;
 334                 list = temp->next;
 335                 free(temp);
 336         }
 337 }
 338
 339 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 340 {
 341         struct commit_list **pp = list;
 342         struct commit_list *p;
 343         while ((p = *pp) != NULL) {
 344                 if (p->item->date < item->date) {
 345                         break;
 346                 }
 347                 pp = &p->next;
 348         }
 349         return commit_list_insert(item, pp);
 350 }
 351
 352
 353 void sort_by_date(struct commit_list **list)
 354 {
 355         struct commit_list *ret = NULL;
 356         while (*list) {
 357                 insert_by_date((*list)->item, &ret);
 358                 *list = (*list)->next;
 359         }
 360         *list = ret;
 361 }
 362
 363 struct commit *pop_most_recent_commit(struct commit_list **list,
 364                                       unsigned int mark)
 365 {
 366         struct commit *ret = (*list)->item;
 367         struct commit_list *parents = ret->parents;
 368         struct commit_list *old = *list;
 369
 370         *list = (*list)->next;
 371         free(old);
 372
 373         while (parents) {
 374                 struct commit *commit = parents->item;
 375                 parse_commit(commit);
 376                 if (!(commit->object.flags & mark)) {
 377                         commit->object.flags |= mark;
 378                         insert_by_date(commit, list);
 379                 }
 380                 parents = parents->next;
 381         }
 382         return ret;
 383 }
 384
 385 void clear_commit_marks(struct commit *commit, unsigned int mark)
 386 {
 387         while (commit) {
 388                 struct commit_list *parents;
 389
 390                 if (!(mark & commit->object.flags))
 391                         return;
 392
 393                 commit->object.flags &= ~mark;
 394
 395                 parents = commit->parents;
 396                 if (!parents)
 397                         return;
 398
 399                 while ((parents = parents->next))
 400                         clear_commit_marks(parents->item, mark);
 401
 402                 commit = commit->parents->item;
 403         }
 404 }
 405
 406 struct commit *pop_commit(struct commit_list **stack)
 407 {
 408         struct commit_list *top = *stack;
 409         struct commit *item = top ? top->item : NULL;
 410
 411         if (top) {
 412                 *stack = top->next;
 413                 free(top);
 414         }
 415         return item;
 416 }
 417
 418 /*
 419  * Performs an in-place topological sort on the list supplied.
 420  */
 421 void sort_in_topological_order(struct commit_list ** list, int lifo)
 422 {
 423         struct commit_list *next, *orig = *list;
 424         struct commit_list *work, **insert;
 425         struct commit_list **pptr;
 426
 427         if (!orig)
 428                 return;
 429         *list = NULL;
 430
 431         /* Mark them and clear the indegree */
 432         for (next = orig; next; next = next->next) {
 433                 struct commit *commit = next->item;
 434                 commit->object.flags |= TOPOSORT;
 435                 commit->indegree = 0;
 436         }
 437
 438         /* update the indegree */
 439         for (next = orig; next; next = next->next) {
 440                 struct commit_list * parents = next->item->parents;
 441                 while (parents) {
 442                         struct commit *parent = parents->item;
 443
 444                         if (parent->object.flags & TOPOSORT)
 445                                 parent->indegree++;
 446                         parents = parents->next;
 447                 }
 448         }
 449
 450         /*
 451          * find the tips
 452          *
 453          * tips are nodes not reachable from any other node in the list
 454          *
 455          * the tips serve as a starting set for the work queue.
 456          */
 457         work = NULL;
 458         insert = &work;
 459         for (next = orig; next; next = next->next) {
 460                 struct commit *commit = next->item;
 461
 462                 if (!commit->indegree)
 463                         insert = &commit_list_insert(commit, insert)->next;
 464         }
 465
 466         /* process the list in topological order */
 467         if (!lifo)
 468                 sort_by_date(&work);
 469
 470         pptr = list;
 471         *list = NULL;
 472         while (work) {
 473                 struct commit *commit;
 474                 struct commit_list *parents, *work_item;
 475
 476                 work_item = work;
 477                 work = work_item->next;
 478                 work_item->next = NULL;
 479
 480                 commit = work_item->item;
 481                 for (parents = commit->parents; parents ; parents = parents->next) {
 482                         struct commit *parent=parents->item;
 483
 484                         if (!(parent->object.flags & TOPOSORT))
 485                                 continue;
 486
 487                         /*
 488                          * parents are only enqueued for emission
 489                          * when all their children have been emitted thereby
 490                          * guaranteeing topological order.
 491                          */
 492                         if (!--parent->indegree) {
 493                                 if (!lifo)
 494                                         insert_by_date(parent, &work);
 495                                 else
 496                                         commit_list_insert(parent, &work);
 497                         }
 498                 }
 499                 /*
 500                  * work_item is a commit all of whose children
 501                  * have already been emitted. we can emit it now.
 502                  */
 503                 commit->object.flags &= ~TOPOSORT;
 504                 *pptr = work_item;
 505                 pptr = &work_item->next;
 506         }
 507 }
 508
 509 /* merge-base stuff */
 510
 511 /* bits #0..15 in revision.h */
 512 #define PARENT1         (1u<<16)
 513 #define PARENT2         (1u<<17)
 514 #define STALE           (1u<<18)
 515 #define RESULT          (1u<<19)
 516
 517 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 518
 519 static struct commit *interesting(struct commit_list *list)
 520 {
 521         while (list) {
 522                 struct commit *commit = list->item;
 523                 list = list->next;
 524                 if (commit->object.flags & STALE)
 525                         continue;
 526                 return commit;
 527         }
 528         return NULL;
 529 }
 530
 531 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 532 {
 533         struct commit_list *list = NULL;
 534         struct commit_list *result = NULL;
 535
 536         if (one == two)
 537                 /* We do not mark this even with RESULT so we do not
 538                  * have to clean it up.
 539                  */
 540                 return commit_list_insert(one, &result);
 541
 542         parse_commit(one);
 543         parse_commit(two);
 544
 545         one->object.flags |= PARENT1;
 546         two->object.flags |= PARENT2;
 547         insert_by_date(one, &list);
 548         insert_by_date(two, &list);
 549
 550         while (interesting(list)) {
 551                 struct commit *commit;
 552                 struct commit_list *parents;
 553                 struct commit_list *n;
 554                 int flags;
 555
 556                 commit = list->item;
 557                 n = list->next;
 558                 free(list);
 559                 list = n;
 560
 561                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 562                 if (flags == (PARENT1 | PARENT2)) {
 563                         if (!(commit->object.flags & RESULT)) {
 564                                 commit->object.flags |= RESULT;
 565                                 insert_by_date(commit, &result);
 566                         }
 567                         /* Mark parents of a found merge stale */
 568                         flags |= STALE;
 569                 }
 570                 parents = commit->parents;
 571                 while (parents) {
 572                         struct commit *p = parents->item;
 573                         parents = parents->next;
 574                         if ((p->object.flags & flags) == flags)
 575                                 continue;
 576                         parse_commit(p);
 577                         p->object.flags |= flags;
 578                         insert_by_date(p, &list);
 579                 }
 580         }
 581
 582         /* Clean up the result to remove stale ones */
 583         free_commit_list(list);
 584         list = result; result = NULL;
 585         while (list) {
 586                 struct commit_list *n = list->next;
 587                 if (!(list->item->object.flags & STALE))
 588                         insert_by_date(list->item, &result);
 589                 free(list);
 590                 list = n;
 591         }
 592         return result;
 593 }
 594
 595 struct commit_list *get_merge_bases(struct commit *one,
 596                                         struct commit *two, int cleanup)
 597 {
 598         struct commit_list *list;
 599         struct commit **rslt;
 600         struct commit_list *result;
 601         int cnt, i, j;
 602
 603         result = merge_bases(one, two);
 604         if (one == two)
 605                 return result;
 606         if (!result || !result->next) {
 607                 if (cleanup) {
 608                         clear_commit_marks(one, all_flags);
 609                         clear_commit_marks(two, all_flags);
 610                 }
 611                 return result;
 612         }
 613
 614         /* There are more than one */
 615         cnt = 0;
 616         list = result;
 617         while (list) {
 618                 list = list->next;
 619                 cnt++;
 620         }
 621         rslt = xcalloc(cnt, sizeof(*rslt));
 622         for (list = result, i = 0; list; list = list->next)
 623                 rslt[i++] = list->item;
 624         free_commit_list(result);
 625
 626         clear_commit_marks(one, all_flags);
 627         clear_commit_marks(two, all_flags);
 628         for (i = 0; i < cnt - 1; i++) {
 629                 for (j = i+1; j < cnt; j++) {
 630                         if (!rslt[i] || !rslt[j])
 631                                 continue;
 632                         result = merge_bases(rslt[i], rslt[j]);
 633                         clear_commit_marks(rslt[i], all_flags);
 634                         clear_commit_marks(rslt[j], all_flags);
 635                         for (list = result; list; list = list->next) {
 636                                 if (rslt[i] == list->item)
 637                                         rslt[i] = NULL;
 638                                 if (rslt[j] == list->item)
 639                                         rslt[j] = NULL;
 640                         }
 641                 }
 642         }
 643
 644         /* Surviving ones in rslt[] are the independent results */
 645         result = NULL;
 646         for (i = 0; i < cnt; i++) {
 647                 if (rslt[i])
 648                         insert_by_date(rslt[i], &result);
 649         }
 650         free(rslt);
 651         return result;
 652 }
 653
 654 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 655 {
 656         struct commit_list *bases, *b;
 657         int ret = 0;
 658
 659         if (num == 1)
 660                 bases = get_merge_bases(commit, *reference, 1);
 661         else
 662                 die("not yet");
 663         for (b = bases; b; b = b->next) {
 664                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 665                         ret = 1;
 666                         break;
 667                 }
 668         }
 669
 670         free_commit_list(bases);
 671         return ret;
 672 }