Andrew's git / gitweb.git / commit.c
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commit.con commit correct argument checking test for git hash-object (8101407)
   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
   9int save_commit_buffer = 1;
  10
  11const char *commit_type = "commit";
  12
  13static 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
  26struct 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
  36struct commit *lookup_commit_reference(const unsigned char *sha1)
  37{
  38        return lookup_commit_reference_gently(sha1, 0);
  39}
  40
  41struct 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
  51static unsigned long parse_commit_date(const char *buf, const char *tail)
  52{
  53        unsigned long date;
  54        const char *dateptr;
  55
  56        if (buf + 6 >= tail)
  57                return 0;
  58        if (memcmp(buf, "author", 6))
  59                return 0;
  60        while (buf < tail && *buf++ != '\n')
  61                /* nada */;
  62        if (buf + 9 >= tail)
  63                return 0;
  64        if (memcmp(buf, "committer", 9))
  65                return 0;
  66        while (buf < tail && *buf++ != '>')
  67                /* nada */;
  68        if (buf >= tail)
  69                return 0;
  70        dateptr = buf;
  71        while (buf < tail && *buf++ != '\n')
  72                /* nada */;
  73        if (buf >= tail)
  74                return 0;
  75        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  76        date = strtoul(dateptr, NULL, 10);
  77        if (date == ULONG_MAX)
  78                date = 0;
  79        return date;
  80}
  81
  82static struct commit_graft **commit_graft;
  83static int commit_graft_alloc, commit_graft_nr;
  84
  85static int commit_graft_pos(const unsigned char *sha1)
  86{
  87        int lo, hi;
  88        lo = 0;
  89        hi = commit_graft_nr;
  90        while (lo < hi) {
  91                int mi = (lo + hi) / 2;
  92                struct commit_graft *graft = commit_graft[mi];
  93                int cmp = hashcmp(sha1, graft->sha1);
  94                if (!cmp)
  95                        return mi;
  96                if (cmp < 0)
  97                        hi = mi;
  98                else
  99                        lo = mi + 1;
 100        }
 101        return -lo - 1;
 102}
 103
 104int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 105{
 106        int pos = commit_graft_pos(graft->sha1);
 107
 108        if (0 <= pos) {
 109                if (ignore_dups)
 110                        free(graft);
 111                else {
 112                        free(commit_graft[pos]);
 113                        commit_graft[pos] = graft;
 114                }
 115                return 1;
 116        }
 117        pos = -pos - 1;
 118        if (commit_graft_alloc <= ++commit_graft_nr) {
 119                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 120                commit_graft = xrealloc(commit_graft,
 121                                        sizeof(*commit_graft) *
 122                                        commit_graft_alloc);
 123        }
 124        if (pos < commit_graft_nr)
 125                memmove(commit_graft + pos + 1,
 126                        commit_graft + pos,
 127                        (commit_graft_nr - pos - 1) *
 128                        sizeof(*commit_graft));
 129        commit_graft[pos] = graft;
 130        return 0;
 131}
 132
 133struct commit_graft *read_graft_line(char *buf, int len)
 134{
 135        /* The format is just "Commit Parent1 Parent2 ...\n" */
 136        int i;
 137        struct commit_graft *graft = NULL;
 138
 139        if (buf[len-1] == '\n')
 140                buf[--len] = 0;
 141        if (buf[0] == '#' || buf[0] == '\0')
 142                return NULL;
 143        if ((len + 1) % 41) {
 144        bad_graft_data:
 145                error("bad graft data: %s", buf);
 146                free(graft);
 147                return NULL;
 148        }
 149        i = (len + 1) / 41 - 1;
 150        graft = xmalloc(sizeof(*graft) + 20 * i);
 151        graft->nr_parent = i;
 152        if (get_sha1_hex(buf, graft->sha1))
 153                goto bad_graft_data;
 154        for (i = 40; i < len; i += 41) {
 155                if (buf[i] != ' ')
 156                        goto bad_graft_data;
 157                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 158                        goto bad_graft_data;
 159        }
 160        return graft;
 161}
 162
 163int read_graft_file(const char *graft_file)
 164{
 165        FILE *fp = fopen(graft_file, "r");
 166        char buf[1024];
 167        if (!fp)
 168                return -1;
 169        while (fgets(buf, sizeof(buf), fp)) {
 170                /* The format is just "Commit Parent1 Parent2 ...\n" */
 171                int len = strlen(buf);
 172                struct commit_graft *graft = read_graft_line(buf, len);
 173                if (!graft)
 174                        continue;
 175                if (register_commit_graft(graft, 1))
 176                        error("duplicate graft data: %s", buf);
 177        }
 178        fclose(fp);
 179        return 0;
 180}
 181
 182static void prepare_commit_graft(void)
 183{
 184        static int commit_graft_prepared;
 185        char *graft_file;
 186
 187        if (commit_graft_prepared)
 188                return;
 189        graft_file = get_graft_file();
 190        read_graft_file(graft_file);
 191        /* make sure shallows are read */
 192        is_repository_shallow();
 193        commit_graft_prepared = 1;
 194}
 195
 196struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 197{
 198        int pos;
 199        prepare_commit_graft();
 200        pos = commit_graft_pos(sha1);
 201        if (pos < 0)
 202                return NULL;
 203        return commit_graft[pos];
 204}
 205
 206int write_shallow_commits(int fd, int use_pack_protocol)
 207{
 208        int i, count = 0;
 209        for (i = 0; i < commit_graft_nr; i++)
 210                if (commit_graft[i]->nr_parent < 0) {
 211                        const char *hex =
 212                                sha1_to_hex(commit_graft[i]->sha1);
 213                        count++;
 214                        if (use_pack_protocol)
 215                                packet_write(fd, "shallow %s", hex);
 216                        else {
 217                                if (write_in_full(fd, hex,  40) != 40)
 218                                        break;
 219                                if (write_in_full(fd, "\n", 1) != 1)
 220                                        break;
 221                        }
 222                }
 223        return count;
 224}
 225
 226int unregister_shallow(const unsigned char *sha1)
 227{
 228        int pos = commit_graft_pos(sha1);
 229        if (pos < 0)
 230                return -1;
 231        if (pos + 1 < commit_graft_nr)
 232                memcpy(commit_graft + pos, commit_graft + pos + 1,
 233                                sizeof(struct commit_graft *)
 234                                * (commit_graft_nr - pos - 1));
 235        commit_graft_nr--;
 236        return 0;
 237}
 238
 239int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 240{
 241        char *tail = buffer;
 242        char *bufptr = buffer;
 243        unsigned char parent[20];
 244        struct commit_list **pptr;
 245        struct commit_graft *graft;
 246
 247        if (item->object.parsed)
 248                return 0;
 249        item->object.parsed = 1;
 250        tail += size;
 251        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 252                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 253        if (get_sha1_hex(bufptr + 5, parent) < 0)
 254                return error("bad tree pointer in commit %s",
 255                             sha1_to_hex(item->object.sha1));
 256        item->tree = lookup_tree(parent);
 257        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 258        pptr = &item->parents;
 259
 260        graft = lookup_commit_graft(item->object.sha1);
 261        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 262                struct commit *new_parent;
 263
 264                if (tail <= bufptr + 48 ||
 265                    get_sha1_hex(bufptr + 7, parent) ||
 266                    bufptr[47] != '\n')
 267                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 268                bufptr += 48;
 269                if (graft)
 270                        continue;
 271                new_parent = lookup_commit(parent);
 272                if (new_parent)
 273                        pptr = &commit_list_insert(new_parent, pptr)->next;
 274        }
 275        if (graft) {
 276                int i;
 277                struct commit *new_parent;
 278                for (i = 0; i < graft->nr_parent; i++) {
 279                        new_parent = lookup_commit(graft->parent[i]);
 280                        if (!new_parent)
 281                                continue;
 282                        pptr = &commit_list_insert(new_parent, pptr)->next;
 283                }
 284        }
 285        item->date = parse_commit_date(bufptr, tail);
 286
 287        return 0;
 288}
 289
 290int parse_commit(struct commit *item)
 291{
 292        enum object_type type;
 293        void *buffer;
 294        unsigned long size;
 295        int ret;
 296
 297        if (!item)
 298                return -1;
 299        if (item->object.parsed)
 300                return 0;
 301        buffer = read_sha1_file(item->object.sha1, &type, &size);
 302        if (!buffer)
 303                return error("Could not read %s",
 304                             sha1_to_hex(item->object.sha1));
 305        if (type != OBJ_COMMIT) {
 306                free(buffer);
 307                return error("Object %s not a commit",
 308                             sha1_to_hex(item->object.sha1));
 309        }
 310        ret = parse_commit_buffer(item, buffer, size);
 311        if (save_commit_buffer && !ret) {
 312                item->buffer = buffer;
 313                return 0;
 314        }
 315        free(buffer);
 316        return ret;
 317}
 318
 319struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 320{
 321        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 322        new_list->item = item;
 323        new_list->next = *list_p;
 324        *list_p = new_list;
 325        return new_list;
 326}
 327
 328unsigned commit_list_count(const struct commit_list *l)
 329{
 330        unsigned c = 0;
 331        for (; l; l = l->next )
 332                c++;
 333        return c;
 334}
 335
 336void free_commit_list(struct commit_list *list)
 337{
 338        while (list) {
 339                struct commit_list *temp = list;
 340                list = temp->next;
 341                free(temp);
 342        }
 343}
 344
 345struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 346{
 347        struct commit_list **pp = list;
 348        struct commit_list *p;
 349        while ((p = *pp) != NULL) {
 350                if (p->item->date < item->date) {
 351                        break;
 352                }
 353                pp = &p->next;
 354        }
 355        return commit_list_insert(item, pp);
 356}
 357
 358
 359void sort_by_date(struct commit_list **list)
 360{
 361        struct commit_list *ret = NULL;
 362        while (*list) {
 363                insert_by_date((*list)->item, &ret);
 364                *list = (*list)->next;
 365        }
 366        *list = ret;
 367}
 368
 369struct commit *pop_most_recent_commit(struct commit_list **list,
 370                                      unsigned int mark)
 371{
 372        struct commit *ret = (*list)->item;
 373        struct commit_list *parents = ret->parents;
 374        struct commit_list *old = *list;
 375
 376        *list = (*list)->next;
 377        free(old);
 378
 379        while (parents) {
 380                struct commit *commit = parents->item;
 381                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 382                        commit->object.flags |= mark;
 383                        insert_by_date(commit, list);
 384                }
 385                parents = parents->next;
 386        }
 387        return ret;
 388}
 389
 390void clear_commit_marks(struct commit *commit, unsigned int mark)
 391{
 392        while (commit) {
 393                struct commit_list *parents;
 394
 395                if (!(mark & commit->object.flags))
 396                        return;
 397
 398                commit->object.flags &= ~mark;
 399
 400                parents = commit->parents;
 401                if (!parents)
 402                        return;
 403
 404                while ((parents = parents->next))
 405                        clear_commit_marks(parents->item, mark);
 406
 407                commit = commit->parents->item;
 408        }
 409}
 410
 411struct commit *pop_commit(struct commit_list **stack)
 412{
 413        struct commit_list *top = *stack;
 414        struct commit *item = top ? top->item : NULL;
 415
 416        if (top) {
 417                *stack = top->next;
 418                free(top);
 419        }
 420        return item;
 421}
 422
 423/*
 424 * Performs an in-place topological sort on the list supplied.
 425 */
 426void sort_in_topological_order(struct commit_list ** list, int lifo)
 427{
 428        struct commit_list *next, *orig = *list;
 429        struct commit_list *work, **insert;
 430        struct commit_list **pptr;
 431
 432        if (!orig)
 433                return;
 434        *list = NULL;
 435
 436        /* Mark them and clear the indegree */
 437        for (next = orig; next; next = next->next) {
 438                struct commit *commit = next->item;
 439                commit->indegree = 1;
 440        }
 441
 442        /* update the indegree */
 443        for (next = orig; next; next = next->next) {
 444                struct commit_list * parents = next->item->parents;
 445                while (parents) {
 446                        struct commit *parent = parents->item;
 447
 448                        if (parent->indegree)
 449                                parent->indegree++;
 450                        parents = parents->next;
 451                }
 452        }
 453
 454        /*
 455         * find the tips
 456         *
 457         * tips are nodes not reachable from any other node in the list
 458         *
 459         * the tips serve as a starting set for the work queue.
 460         */
 461        work = NULL;
 462        insert = &work;
 463        for (next = orig; next; next = next->next) {
 464                struct commit *commit = next->item;
 465
 466                if (commit->indegree == 1)
 467                        insert = &commit_list_insert(commit, insert)->next;
 468        }
 469
 470        /* process the list in topological order */
 471        if (!lifo)
 472                sort_by_date(&work);
 473
 474        pptr = list;
 475        *list = NULL;
 476        while (work) {
 477                struct commit *commit;
 478                struct commit_list *parents, *work_item;
 479
 480                work_item = work;
 481                work = work_item->next;
 482                work_item->next = NULL;
 483
 484                commit = work_item->item;
 485                for (parents = commit->parents; parents ; parents = parents->next) {
 486                        struct commit *parent=parents->item;
 487
 488                        if (!parent->indegree)
 489                                continue;
 490
 491                        /*
 492                         * parents are only enqueued for emission
 493                         * when all their children have been emitted thereby
 494                         * guaranteeing topological order.
 495                         */
 496                        if (--parent->indegree == 1) {
 497                                if (!lifo)
 498                                        insert_by_date(parent, &work);
 499                                else
 500                                        commit_list_insert(parent, &work);
 501                        }
 502                }
 503                /*
 504                 * work_item is a commit all of whose children
 505                 * have already been emitted. we can emit it now.
 506                 */
 507                commit->indegree = 0;
 508                *pptr = work_item;
 509                pptr = &work_item->next;
 510        }
 511}
 512
 513/* merge-base stuff */
 514
 515/* bits #0..15 in revision.h */
 516#define PARENT1         (1u<<16)
 517#define PARENT2         (1u<<17)
 518#define STALE           (1u<<18)
 519#define RESULT          (1u<<19)
 520
 521static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 522
 523static struct commit *interesting(struct commit_list *list)
 524{
 525        while (list) {
 526                struct commit *commit = list->item;
 527                list = list->next;
 528                if (commit->object.flags & STALE)
 529                        continue;
 530                return commit;
 531        }
 532        return NULL;
 533}
 534
 535static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 536{
 537        struct commit_list *list = NULL;
 538        struct commit_list *result = NULL;
 539        int i;
 540
 541        for (i = 0; i < n; i++) {
 542                if (one == twos[i])
 543                        /*
 544                         * We do not mark this even with RESULT so we do not
 545                         * have to clean it up.
 546                         */
 547                        return commit_list_insert(one, &result);
 548        }
 549
 550        if (parse_commit(one))
 551                return NULL;
 552        for (i = 0; i < n; i++) {
 553                if (parse_commit(twos[i]))
 554                        return NULL;
 555        }
 556
 557        one->object.flags |= PARENT1;
 558        insert_by_date(one, &list);
 559        for (i = 0; i < n; i++) {
 560                twos[i]->object.flags |= PARENT2;
 561                insert_by_date(twos[i], &list);
 562        }
 563
 564        while (interesting(list)) {
 565                struct commit *commit;
 566                struct commit_list *parents;
 567                struct commit_list *n;
 568                int flags;
 569
 570                commit = list->item;
 571                n = list->next;
 572                free(list);
 573                list = n;
 574
 575                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 576                if (flags == (PARENT1 | PARENT2)) {
 577                        if (!(commit->object.flags & RESULT)) {
 578                                commit->object.flags |= RESULT;
 579                                insert_by_date(commit, &result);
 580                        }
 581                        /* Mark parents of a found merge stale */
 582                        flags |= STALE;
 583                }
 584                parents = commit->parents;
 585                while (parents) {
 586                        struct commit *p = parents->item;
 587                        parents = parents->next;
 588                        if ((p->object.flags & flags) == flags)
 589                                continue;
 590                        if (parse_commit(p))
 591                                return NULL;
 592                        p->object.flags |= flags;
 593                        insert_by_date(p, &list);
 594                }
 595        }
 596
 597        /* Clean up the result to remove stale ones */
 598        free_commit_list(list);
 599        list = result; result = NULL;
 600        while (list) {
 601                struct commit_list *n = list->next;
 602                if (!(list->item->object.flags & STALE))
 603                        insert_by_date(list->item, &result);
 604                free(list);
 605                list = n;
 606        }
 607        return result;
 608}
 609
 610struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 611{
 612        struct commit_list *i, *j, *k, *ret = NULL;
 613        struct commit_list **pptr = &ret;
 614
 615        for (i = in; i; i = i->next) {
 616                if (!ret)
 617                        pptr = &commit_list_insert(i->item, pptr)->next;
 618                else {
 619                        struct commit_list *new = NULL, *end = NULL;
 620
 621                        for (j = ret; j; j = j->next) {
 622                                struct commit_list *bases;
 623                                bases = get_merge_bases(i->item, j->item, 1);
 624                                if (!new)
 625                                        new = bases;
 626                                else
 627                                        end->next = bases;
 628                                for (k = bases; k; k = k->next)
 629                                        end = k;
 630                        }
 631                        ret = new;
 632                }
 633        }
 634        return ret;
 635}
 636
 637struct commit_list *get_merge_bases_many(struct commit *one,
 638                                         int n,
 639                                         struct commit **twos,
 640                                         int cleanup)
 641{
 642        struct commit_list *list;
 643        struct commit **rslt;
 644        struct commit_list *result;
 645        int cnt, i, j;
 646
 647        result = merge_bases_many(one, n, twos);
 648        for (i = 0; i < n; i++) {
 649                if (one == twos[i])
 650                        return result;
 651        }
 652        if (!result || !result->next) {
 653                if (cleanup) {
 654                        clear_commit_marks(one, all_flags);
 655                        for (i = 0; i < n; i++)
 656                                clear_commit_marks(twos[i], all_flags);
 657                }
 658                return result;
 659        }
 660
 661        /* There are more than one */
 662        cnt = 0;
 663        list = result;
 664        while (list) {
 665                list = list->next;
 666                cnt++;
 667        }
 668        rslt = xcalloc(cnt, sizeof(*rslt));
 669        for (list = result, i = 0; list; list = list->next)
 670                rslt[i++] = list->item;
 671        free_commit_list(result);
 672
 673        clear_commit_marks(one, all_flags);
 674        for (i = 0; i < n; i++)
 675                clear_commit_marks(twos[i], all_flags);
 676        for (i = 0; i < cnt - 1; i++) {
 677                for (j = i+1; j < cnt; j++) {
 678                        if (!rslt[i] || !rslt[j])
 679                                continue;
 680                        result = merge_bases_many(rslt[i], 1, &rslt[j]);
 681                        clear_commit_marks(rslt[i], all_flags);
 682                        clear_commit_marks(rslt[j], all_flags);
 683                        for (list = result; list; list = list->next) {
 684                                if (rslt[i] == list->item)
 685                                        rslt[i] = NULL;
 686                                if (rslt[j] == list->item)
 687                                        rslt[j] = NULL;
 688                        }
 689                }
 690        }
 691
 692        /* Surviving ones in rslt[] are the independent results */
 693        result = NULL;
 694        for (i = 0; i < cnt; i++) {
 695                if (rslt[i])
 696                        insert_by_date(rslt[i], &result);
 697        }
 698        free(rslt);
 699        return result;
 700}
 701
 702struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 703                                    int cleanup)
 704{
 705        return get_merge_bases_many(one, 1, &two, cleanup);
 706}
 707
 708int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 709{
 710        struct commit_list *bases, *b;
 711        int ret = 0;
 712
 713        if (num == 1)
 714                bases = get_merge_bases(commit, *reference, 1);
 715        else
 716                die("not yet");
 717        for (b = bases; b; b = b->next) {
 718                if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 719                        ret = 1;
 720                        break;
 721                }
 722        }
 723
 724        free_commit_list(bases);
 725        return ret;
 726}
 727
 728struct commit_list *reduce_heads(struct commit_list *heads)
 729{
 730        struct commit_list *p;
 731        struct commit_list *result = NULL, **tail = &result;
 732        struct commit **other;
 733        size_t num_head, num_other;
 734
 735        if (!heads)
 736                return NULL;
 737
 738        /* Avoid unnecessary reallocations */
 739        for (p = heads, num_head = 0; p; p = p->next)
 740                num_head++;
 741        other = xcalloc(sizeof(*other), num_head);
 742
 743        /* For each commit, see if it can be reached by others */
 744        for (p = heads; p; p = p->next) {
 745                struct commit_list *q, *base;
 746
 747                /* Do we already have this in the result? */
 748                for (q = result; q; q = q->next)
 749                        if (p->item == q->item)
 750                                break;
 751                if (q)
 752                        continue;
 753
 754                num_other = 0;
 755                for (q = heads; q; q = q->next) {
 756                        if (p->item == q->item)
 757                                continue;
 758                        other[num_other++] = q->item;
 759                }
 760                if (num_other)
 761                        base = get_merge_bases_many(p->item, num_other, other, 1);
 762                else
 763                        base = NULL;
 764                /*
 765                 * If p->item does not have anything common with other
 766                 * commits, there won't be any merge base.  If it is
 767                 * reachable from some of the others, p->item will be
 768                 * the merge base.  If its history is connected with
 769                 * others, but p->item is not reachable by others, we
 770                 * will get something other than p->item back.
 771                 */
 772                if (!base || (base->item != p->item))
 773                        tail = &(commit_list_insert(p->item, tail)->next);
 774                free_commit_list(base);
 775        }
 776        free(other);
 777        return result;
 778}