commit.con commit Merge branch 'xx/trivial' into maint (af24059)
   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
  10int save_commit_buffer = 1;
  11
  12const char *commit_type = "commit";
  13
  14static struct commit *check_commit(struct object *obj,
  15                                   const unsigned char *sha1,
  16                                   int quiet)
  17{
  18        if (obj->type != OBJ_COMMIT) {
  19                if (!quiet)
  20                        error("Object %s is a %s, not a commit",
  21                              sha1_to_hex(sha1), typename(obj->type));
  22                return NULL;
  23        }
  24        return (struct commit *) obj;
  25}
  26
  27struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  28                                              int quiet)
  29{
  30        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  31
  32        if (!obj)
  33                return NULL;
  34        return check_commit(obj, sha1, quiet);
  35}
  36
  37struct commit *lookup_commit_reference(const unsigned char *sha1)
  38{
  39        return lookup_commit_reference_gently(sha1, 0);
  40}
  41
  42struct commit *lookup_commit(const unsigned char *sha1)
  43{
  44        struct object *obj = lookup_object(sha1);
  45        if (!obj)
  46                return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  47        if (!obj->type)
  48                obj->type = OBJ_COMMIT;
  49        return check_commit(obj, sha1, 0);
  50}
  51
  52static unsigned long parse_commit_date(const char *buf, const char *tail)
  53{
  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        return strtoul(dateptr, NULL, 10);
  77}
  78
  79static struct commit_graft **commit_graft;
  80static int commit_graft_alloc, commit_graft_nr;
  81
  82static int commit_graft_pos(const unsigned char *sha1)
  83{
  84        int lo, hi;
  85        lo = 0;
  86        hi = commit_graft_nr;
  87        while (lo < hi) {
  88                int mi = (lo + hi) / 2;
  89                struct commit_graft *graft = commit_graft[mi];
  90                int cmp = hashcmp(sha1, graft->sha1);
  91                if (!cmp)
  92                        return mi;
  93                if (cmp < 0)
  94                        hi = mi;
  95                else
  96                        lo = mi + 1;
  97        }
  98        return -lo - 1;
  99}
 100
 101int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 102{
 103        int pos = commit_graft_pos(graft->sha1);
 104
 105        if (0 <= pos) {
 106                if (ignore_dups)
 107                        free(graft);
 108                else {
 109                        free(commit_graft[pos]);
 110                        commit_graft[pos] = graft;
 111                }
 112                return 1;
 113        }
 114        pos = -pos - 1;
 115        if (commit_graft_alloc <= ++commit_graft_nr) {
 116                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 117                commit_graft = xrealloc(commit_graft,
 118                                        sizeof(*commit_graft) *
 119                                        commit_graft_alloc);
 120        }
 121        if (pos < commit_graft_nr)
 122                memmove(commit_graft + pos + 1,
 123                        commit_graft + pos,
 124                        (commit_graft_nr - pos - 1) *
 125                        sizeof(*commit_graft));
 126        commit_graft[pos] = graft;
 127        return 0;
 128}
 129
 130struct commit_graft *read_graft_line(char *buf, int len)
 131{
 132        /* The format is just "Commit Parent1 Parent2 ...\n" */
 133        int i;
 134        struct commit_graft *graft = NULL;
 135
 136        while (len && isspace(buf[len-1]))
 137                buf[--len] = '\0';
 138        if (buf[0] == '#' || buf[0] == '\0')
 139                return NULL;
 140        if ((len + 1) % 41) {
 141        bad_graft_data:
 142                error("bad graft data: %s", buf);
 143                free(graft);
 144                return NULL;
 145        }
 146        i = (len + 1) / 41 - 1;
 147        graft = xmalloc(sizeof(*graft) + 20 * i);
 148        graft->nr_parent = i;
 149        if (get_sha1_hex(buf, graft->sha1))
 150                goto bad_graft_data;
 151        for (i = 40; i < len; i += 41) {
 152                if (buf[i] != ' ')
 153                        goto bad_graft_data;
 154                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 155                        goto bad_graft_data;
 156        }
 157        return graft;
 158}
 159
 160static int read_graft_file(const char *graft_file)
 161{
 162        FILE *fp = fopen(graft_file, "r");
 163        char buf[1024];
 164        if (!fp)
 165                return -1;
 166        while (fgets(buf, sizeof(buf), fp)) {
 167                /* The format is just "Commit Parent1 Parent2 ...\n" */
 168                int len = strlen(buf);
 169                struct commit_graft *graft = read_graft_line(buf, len);
 170                if (!graft)
 171                        continue;
 172                if (register_commit_graft(graft, 1))
 173                        error("duplicate graft data: %s", buf);
 174        }
 175        fclose(fp);
 176        return 0;
 177}
 178
 179static void prepare_commit_graft(void)
 180{
 181        static int commit_graft_prepared;
 182        char *graft_file;
 183
 184        if (commit_graft_prepared)
 185                return;
 186        graft_file = get_graft_file();
 187        read_graft_file(graft_file);
 188        /* make sure shallows are read */
 189        is_repository_shallow();
 190        commit_graft_prepared = 1;
 191}
 192
 193struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 194{
 195        int pos;
 196        prepare_commit_graft();
 197        pos = commit_graft_pos(sha1);
 198        if (pos < 0)
 199                return NULL;
 200        return commit_graft[pos];
 201}
 202
 203int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
 204{
 205        int i, count = 0;
 206        for (i = 0; i < commit_graft_nr; i++)
 207                if (commit_graft[i]->nr_parent < 0) {
 208                        const char *hex =
 209                                sha1_to_hex(commit_graft[i]->sha1);
 210                        count++;
 211                        if (use_pack_protocol)
 212                                packet_buf_write(out, "shallow %s", hex);
 213                        else {
 214                                strbuf_addstr(out, hex);
 215                                strbuf_addch(out, '\n');
 216                        }
 217                }
 218        return count;
 219}
 220
 221int unregister_shallow(const unsigned char *sha1)
 222{
 223        int pos = commit_graft_pos(sha1);
 224        if (pos < 0)
 225                return -1;
 226        if (pos + 1 < commit_graft_nr)
 227                memmove(commit_graft + pos, commit_graft + pos + 1,
 228                                sizeof(struct commit_graft *)
 229                                * (commit_graft_nr - pos - 1));
 230        commit_graft_nr--;
 231        return 0;
 232}
 233
 234int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 235{
 236        char *tail = buffer;
 237        char *bufptr = buffer;
 238        unsigned char parent[20];
 239        struct commit_list **pptr;
 240        struct commit_graft *graft;
 241
 242        if (item->object.parsed)
 243                return 0;
 244        item->object.parsed = 1;
 245        tail += size;
 246        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 247                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 248        if (get_sha1_hex(bufptr + 5, parent) < 0)
 249                return error("bad tree pointer in commit %s",
 250                             sha1_to_hex(item->object.sha1));
 251        item->tree = lookup_tree(parent);
 252        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 253        pptr = &item->parents;
 254
 255        graft = lookup_commit_graft(item->object.sha1);
 256        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 257                struct commit *new_parent;
 258
 259                if (tail <= bufptr + 48 ||
 260                    get_sha1_hex(bufptr + 7, parent) ||
 261                    bufptr[47] != '\n')
 262                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 263                bufptr += 48;
 264                /*
 265                 * The clone is shallow if nr_parent < 0, and we must
 266                 * not traverse its real parents even when we unhide them.
 267                 */
 268                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 269                        continue;
 270                new_parent = lookup_commit(parent);
 271                if (new_parent)
 272                        pptr = &commit_list_insert(new_parent, pptr)->next;
 273        }
 274        if (graft) {
 275                int i;
 276                struct commit *new_parent;
 277                for (i = 0; i < graft->nr_parent; i++) {
 278                        new_parent = lookup_commit(graft->parent[i]);
 279                        if (!new_parent)
 280                                continue;
 281                        pptr = &commit_list_insert(new_parent, pptr)->next;
 282                }
 283        }
 284        item->date = parse_commit_date(bufptr, tail);
 285
 286        return 0;
 287}
 288
 289int parse_commit(struct commit *item)
 290{
 291        enum object_type type;
 292        void *buffer;
 293        unsigned long size;
 294        int ret;
 295
 296        if (!item)
 297                return -1;
 298        if (item->object.parsed)
 299                return 0;
 300        buffer = read_sha1_file(item->object.sha1, &type, &size);
 301        if (!buffer)
 302                return error("Could not read %s",
 303                             sha1_to_hex(item->object.sha1));
 304        if (type != OBJ_COMMIT) {
 305                free(buffer);
 306                return error("Object %s not a commit",
 307                             sha1_to_hex(item->object.sha1));
 308        }
 309        ret = parse_commit_buffer(item, buffer, size);
 310        if (save_commit_buffer && !ret) {
 311                item->buffer = buffer;
 312                return 0;
 313        }
 314        free(buffer);
 315        return ret;
 316}
 317
 318struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 319{
 320        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 321        new_list->item = item;
 322        new_list->next = *list_p;
 323        *list_p = new_list;
 324        return new_list;
 325}
 326
 327unsigned commit_list_count(const struct commit_list *l)
 328{
 329        unsigned c = 0;
 330        for (; l; l = l->next )
 331                c++;
 332        return c;
 333}
 334
 335void free_commit_list(struct commit_list *list)
 336{
 337        while (list) {
 338                struct commit_list *temp = list;
 339                list = temp->next;
 340                free(temp);
 341        }
 342}
 343
 344struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 345{
 346        struct commit_list **pp = list;
 347        struct commit_list *p;
 348        while ((p = *pp) != NULL) {
 349                if (p->item->date < item->date) {
 350                        break;
 351                }
 352                pp = &p->next;
 353        }
 354        return commit_list_insert(item, pp);
 355}
 356
 357
 358void sort_by_date(struct commit_list **list)
 359{
 360        struct commit_list *ret = NULL;
 361        while (*list) {
 362                insert_by_date((*list)->item, &ret);
 363                *list = (*list)->next;
 364        }
 365        *list = ret;
 366}
 367
 368struct commit *pop_most_recent_commit(struct commit_list **list,
 369                                      unsigned int mark)
 370{
 371        struct commit *ret = (*list)->item;
 372        struct commit_list *parents = ret->parents;
 373        struct commit_list *old = *list;
 374
 375        *list = (*list)->next;
 376        free(old);
 377
 378        while (parents) {
 379                struct commit *commit = parents->item;
 380                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 381                        commit->object.flags |= mark;
 382                        insert_by_date(commit, list);
 383                }
 384                parents = parents->next;
 385        }
 386        return ret;
 387}
 388
 389void clear_commit_marks(struct commit *commit, unsigned int mark)
 390{
 391        while (commit) {
 392                struct commit_list *parents;
 393
 394                if (!(mark & commit->object.flags))
 395                        return;
 396
 397                commit->object.flags &= ~mark;
 398
 399                parents = commit->parents;
 400                if (!parents)
 401                        return;
 402
 403                while ((parents = parents->next))
 404                        clear_commit_marks(parents->item, mark);
 405
 406                commit = commit->parents->item;
 407        }
 408}
 409
 410struct commit *pop_commit(struct commit_list **stack)
 411{
 412        struct commit_list *top = *stack;
 413        struct commit *item = top ? top->item : NULL;
 414
 415        if (top) {
 416                *stack = top->next;
 417                free(top);
 418        }
 419        return item;
 420}
 421
 422/*
 423 * Performs an in-place topological sort on the list supplied.
 424 */
 425void sort_in_topological_order(struct commit_list ** list, int lifo)
 426{
 427        struct commit_list *next, *orig = *list;
 428        struct commit_list *work, **insert;
 429        struct commit_list **pptr;
 430
 431        if (!orig)
 432                return;
 433        *list = NULL;
 434
 435        /* Mark them and clear the indegree */
 436        for (next = orig; next; next = next->next) {
 437                struct commit *commit = next->item;
 438                commit->indegree = 1;
 439        }
 440
 441        /* update the indegree */
 442        for (next = orig; next; next = next->next) {
 443                struct commit_list * parents = next->item->parents;
 444                while (parents) {
 445                        struct commit *parent = parents->item;
 446
 447                        if (parent->indegree)
 448                                parent->indegree++;
 449                        parents = parents->next;
 450                }
 451        }
 452
 453        /*
 454         * find the tips
 455         *
 456         * tips are nodes not reachable from any other node in the list
 457         *
 458         * the tips serve as a starting set for the work queue.
 459         */
 460        work = NULL;
 461        insert = &work;
 462        for (next = orig; next; next = next->next) {
 463                struct commit *commit = next->item;
 464
 465                if (commit->indegree == 1)
 466                        insert = &commit_list_insert(commit, insert)->next;
 467        }
 468
 469        /* process the list in topological order */
 470        if (!lifo)
 471                sort_by_date(&work);
 472
 473        pptr = list;
 474        *list = NULL;
 475        while (work) {
 476                struct commit *commit;
 477                struct commit_list *parents, *work_item;
 478
 479                work_item = work;
 480                work = work_item->next;
 481                work_item->next = NULL;
 482
 483                commit = work_item->item;
 484                for (parents = commit->parents; parents ; parents = parents->next) {
 485                        struct commit *parent=parents->item;
 486
 487                        if (!parent->indegree)
 488                                continue;
 489
 490                        /*
 491                         * parents are only enqueued for emission
 492                         * when all their children have been emitted thereby
 493                         * guaranteeing topological order.
 494                         */
 495                        if (--parent->indegree == 1) {
 496                                if (!lifo)
 497                                        insert_by_date(parent, &work);
 498                                else
 499                                        commit_list_insert(parent, &work);
 500                        }
 501                }
 502                /*
 503                 * work_item is a commit all of whose children
 504                 * have already been emitted. we can emit it now.
 505                 */
 506                commit->indegree = 0;
 507                *pptr = work_item;
 508                pptr = &work_item->next;
 509        }
 510}
 511
 512/* merge-base stuff */
 513
 514/* bits #0..15 in revision.h */
 515#define PARENT1         (1u<<16)
 516#define PARENT2         (1u<<17)
 517#define STALE           (1u<<18)
 518#define RESULT          (1u<<19)
 519
 520static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 521
 522static struct commit *interesting(struct commit_list *list)
 523{
 524        while (list) {
 525                struct commit *commit = list->item;
 526                list = list->next;
 527                if (commit->object.flags & STALE)
 528                        continue;
 529                return commit;
 530        }
 531        return NULL;
 532}
 533
 534static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 535{
 536        struct commit_list *list = NULL;
 537        struct commit_list *result = NULL;
 538        int i;
 539
 540        for (i = 0; i < n; i++) {
 541                if (one == twos[i])
 542                        /*
 543                         * We do not mark this even with RESULT so we do not
 544                         * have to clean it up.
 545                         */
 546                        return commit_list_insert(one, &result);
 547        }
 548
 549        if (parse_commit(one))
 550                return NULL;
 551        for (i = 0; i < n; i++) {
 552                if (parse_commit(twos[i]))
 553                        return NULL;
 554        }
 555
 556        one->object.flags |= PARENT1;
 557        insert_by_date(one, &list);
 558        for (i = 0; i < n; i++) {
 559                twos[i]->object.flags |= PARENT2;
 560                insert_by_date(twos[i], &list);
 561        }
 562
 563        while (interesting(list)) {
 564                struct commit *commit;
 565                struct commit_list *parents;
 566                struct commit_list *next;
 567                int flags;
 568
 569                commit = list->item;
 570                next = list->next;
 571                free(list);
 572                list = next;
 573
 574                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 575                if (flags == (PARENT1 | PARENT2)) {
 576                        if (!(commit->object.flags & RESULT)) {
 577                                commit->object.flags |= RESULT;
 578                                insert_by_date(commit, &result);
 579                        }
 580                        /* Mark parents of a found merge stale */
 581                        flags |= STALE;
 582                }
 583                parents = commit->parents;
 584                while (parents) {
 585                        struct commit *p = parents->item;
 586                        parents = parents->next;
 587                        if ((p->object.flags & flags) == flags)
 588                                continue;
 589                        if (parse_commit(p))
 590                                return NULL;
 591                        p->object.flags |= flags;
 592                        insert_by_date(p, &list);
 593                }
 594        }
 595
 596        /* Clean up the result to remove stale ones */
 597        free_commit_list(list);
 598        list = result; result = NULL;
 599        while (list) {
 600                struct commit_list *next = list->next;
 601                if (!(list->item->object.flags & STALE))
 602                        insert_by_date(list->item, &result);
 603                free(list);
 604                list = next;
 605        }
 606        return result;
 607}
 608
 609struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 610{
 611        struct commit_list *i, *j, *k, *ret = NULL;
 612        struct commit_list **pptr = &ret;
 613
 614        for (i = in; i; i = i->next) {
 615                if (!ret)
 616                        pptr = &commit_list_insert(i->item, pptr)->next;
 617                else {
 618                        struct commit_list *new = NULL, *end = NULL;
 619
 620                        for (j = ret; j; j = j->next) {
 621                                struct commit_list *bases;
 622                                bases = get_merge_bases(i->item, j->item, 1);
 623                                if (!new)
 624                                        new = bases;
 625                                else
 626                                        end->next = bases;
 627                                for (k = bases; k; k = k->next)
 628                                        end = k;
 629                        }
 630                        ret = new;
 631                }
 632        }
 633        return ret;
 634}
 635
 636struct commit_list *get_merge_bases_many(struct commit *one,
 637                                         int n,
 638                                         struct commit **twos,
 639                                         int cleanup)
 640{
 641        struct commit_list *list;
 642        struct commit **rslt;
 643        struct commit_list *result;
 644        int cnt, i, j;
 645
 646        result = merge_bases_many(one, n, twos);
 647        for (i = 0; i < n; i++) {
 648                if (one == twos[i])
 649                        return result;
 650        }
 651        if (!result || !result->next) {
 652                if (cleanup) {
 653                        clear_commit_marks(one, all_flags);
 654                        for (i = 0; i < n; i++)
 655                                clear_commit_marks(twos[i], all_flags);
 656                }
 657                return result;
 658        }
 659
 660        /* There are more than one */
 661        cnt = 0;
 662        list = result;
 663        while (list) {
 664                list = list->next;
 665                cnt++;
 666        }
 667        rslt = xcalloc(cnt, sizeof(*rslt));
 668        for (list = result, i = 0; list; list = list->next)
 669                rslt[i++] = list->item;
 670        free_commit_list(result);
 671
 672        clear_commit_marks(one, all_flags);
 673        for (i = 0; i < n; i++)
 674                clear_commit_marks(twos[i], all_flags);
 675        for (i = 0; i < cnt - 1; i++) {
 676                for (j = i+1; j < cnt; j++) {
 677                        if (!rslt[i] || !rslt[j])
 678                                continue;
 679                        result = merge_bases_many(rslt[i], 1, &rslt[j]);
 680                        clear_commit_marks(rslt[i], all_flags);
 681                        clear_commit_marks(rslt[j], all_flags);
 682                        for (list = result; list; list = list->next) {
 683                                if (rslt[i] == list->item)
 684                                        rslt[i] = NULL;
 685                                if (rslt[j] == list->item)
 686                                        rslt[j] = NULL;
 687                        }
 688                }
 689        }
 690
 691        /* Surviving ones in rslt[] are the independent results */
 692        result = NULL;
 693        for (i = 0; i < cnt; i++) {
 694                if (rslt[i])
 695                        insert_by_date(rslt[i], &result);
 696        }
 697        free(rslt);
 698        return result;
 699}
 700
 701struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 702                                    int cleanup)
 703{
 704        return get_merge_bases_many(one, 1, &two, cleanup);
 705}
 706
 707int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 708{
 709        if (!with_commit)
 710                return 1;
 711        while (with_commit) {
 712                struct commit *other;
 713
 714                other = with_commit->item;
 715                with_commit = with_commit->next;
 716                if (in_merge_bases(other, &commit, 1))
 717                        return 1;
 718        }
 719        return 0;
 720}
 721
 722int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 723{
 724        struct commit_list *bases, *b;
 725        int ret = 0;
 726
 727        if (num == 1)
 728                bases = get_merge_bases(commit, *reference, 1);
 729        else
 730                die("not yet");
 731        for (b = bases; b; b = b->next) {
 732                if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 733                        ret = 1;
 734                        break;
 735                }
 736        }
 737
 738        free_commit_list(bases);
 739        return ret;
 740}
 741
 742struct commit_list *reduce_heads(struct commit_list *heads)
 743{
 744        struct commit_list *p;
 745        struct commit_list *result = NULL, **tail = &result;
 746        struct commit **other;
 747        size_t num_head, num_other;
 748
 749        if (!heads)
 750                return NULL;
 751
 752        /* Avoid unnecessary reallocations */
 753        for (p = heads, num_head = 0; p; p = p->next)
 754                num_head++;
 755        other = xcalloc(sizeof(*other), num_head);
 756
 757        /* For each commit, see if it can be reached by others */
 758        for (p = heads; p; p = p->next) {
 759                struct commit_list *q, *base;
 760
 761                /* Do we already have this in the result? */
 762                for (q = result; q; q = q->next)
 763                        if (p->item == q->item)
 764                                break;
 765                if (q)
 766                        continue;
 767
 768                num_other = 0;
 769                for (q = heads; q; q = q->next) {
 770                        if (p->item == q->item)
 771                                continue;
 772                        other[num_other++] = q->item;
 773                }
 774                if (num_other)
 775                        base = get_merge_bases_many(p->item, num_other, other, 1);
 776                else
 777                        base = NULL;
 778                /*
 779                 * If p->item does not have anything common with other
 780                 * commits, there won't be any merge base.  If it is
 781                 * reachable from some of the others, p->item will be
 782                 * the merge base.  If its history is connected with
 783                 * others, but p->item is not reachable by others, we
 784                 * will get something other than p->item back.
 785                 */
 786                if (!base || (base->item != p->item))
 787                        tail = &(commit_list_insert(p->item, tail)->next);
 788                free_commit_list(base);
 789        }
 790        free(other);
 791        return result;
 792}
 793
 794static const char commit_utf8_warn[] =
 795"Warning: commit message does not conform to UTF-8.\n"
 796"You may want to amend it after fixing the message, or set the config\n"
 797"variable i18n.commitencoding to the encoding your project uses.\n";
 798
 799int commit_tree(const char *msg, unsigned char *tree,
 800                struct commit_list *parents, unsigned char *ret,
 801                const char *author)
 802{
 803        int result;
 804        int encoding_is_utf8;
 805        struct strbuf buffer;
 806
 807        assert_sha1_type(tree, OBJ_TREE);
 808
 809        /* Not having i18n.commitencoding is the same as having utf-8 */
 810        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
 811
 812        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
 813        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
 814
 815        /*
 816         * NOTE! This ordering means that the same exact tree merged with a
 817         * different order of parents will be a _different_ changeset even
 818         * if everything else stays the same.
 819         */
 820        while (parents) {
 821                struct commit_list *next = parents->next;
 822                strbuf_addf(&buffer, "parent %s\n",
 823                        sha1_to_hex(parents->item->object.sha1));
 824                free(parents);
 825                parents = next;
 826        }
 827
 828        /* Person/date information */
 829        if (!author)
 830                author = git_author_info(IDENT_ERROR_ON_NO_NAME);
 831        strbuf_addf(&buffer, "author %s\n", author);
 832        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_ERROR_ON_NO_NAME));
 833        if (!encoding_is_utf8)
 834                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
 835        strbuf_addch(&buffer, '\n');
 836
 837        /* And add the comment */
 838        strbuf_addstr(&buffer, msg);
 839
 840        /* And check the encoding */
 841        if (encoding_is_utf8 && !is_utf8(buffer.buf))
 842                fprintf(stderr, commit_utf8_warn);
 843
 844        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
 845        strbuf_release(&buffer);
 846        return result;
 847}