commit.con commit assume parse_commit checks for NULL commit (5e7d4d3)
   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "pkt-line.h"
   5#include "utf8.h"
   6#include "diff.h"
   7#include "revision.h"
   8#include "notes.h"
   9#include "gpg-interface.h"
  10#include "mergesort.h"
  11#include "commit-slab.h"
  12#include "prio-queue.h"
  13
  14static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  15
  16int save_commit_buffer = 1;
  17
  18const char *commit_type = "commit";
  19static int commit_count;
  20
  21static struct commit *check_commit(struct object *obj,
  22                                   const unsigned char *sha1,
  23                                   int quiet)
  24{
  25        if (obj->type != OBJ_COMMIT) {
  26                if (!quiet)
  27                        error("Object %s is a %s, not a commit",
  28                              sha1_to_hex(sha1), typename(obj->type));
  29                return NULL;
  30        }
  31        return (struct commit *) obj;
  32}
  33
  34struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  35                                              int quiet)
  36{
  37        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  38
  39        if (!obj)
  40                return NULL;
  41        return check_commit(obj, sha1, quiet);
  42}
  43
  44struct commit *lookup_commit_reference(const unsigned char *sha1)
  45{
  46        return lookup_commit_reference_gently(sha1, 0);
  47}
  48
  49struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  50{
  51        struct commit *c = lookup_commit_reference(sha1);
  52        if (!c)
  53                die(_("could not parse %s"), ref_name);
  54        if (hashcmp(sha1, c->object.sha1)) {
  55                warning(_("%s %s is not a commit!"),
  56                        ref_name, sha1_to_hex(sha1));
  57        }
  58        return c;
  59}
  60
  61struct commit *lookup_commit(const unsigned char *sha1)
  62{
  63        struct object *obj = lookup_object(sha1);
  64        if (!obj) {
  65                struct commit *c = alloc_commit_node();
  66                c->index = commit_count++;
  67                return create_object(sha1, OBJ_COMMIT, c);
  68        }
  69        if (!obj->type)
  70                obj->type = OBJ_COMMIT;
  71        return check_commit(obj, sha1, 0);
  72}
  73
  74struct commit *lookup_commit_reference_by_name(const char *name)
  75{
  76        unsigned char sha1[20];
  77        struct commit *commit;
  78
  79        if (get_sha1_committish(name, sha1))
  80                return NULL;
  81        commit = lookup_commit_reference(sha1);
  82        if (parse_commit(commit))
  83                return NULL;
  84        return commit;
  85}
  86
  87static unsigned long parse_commit_date(const char *buf, const char *tail)
  88{
  89        const char *dateptr;
  90
  91        if (buf + 6 >= tail)
  92                return 0;
  93        if (memcmp(buf, "author", 6))
  94                return 0;
  95        while (buf < tail && *buf++ != '\n')
  96                /* nada */;
  97        if (buf + 9 >= tail)
  98                return 0;
  99        if (memcmp(buf, "committer", 9))
 100                return 0;
 101        while (buf < tail && *buf++ != '>')
 102                /* nada */;
 103        if (buf >= tail)
 104                return 0;
 105        dateptr = buf;
 106        while (buf < tail && *buf++ != '\n')
 107                /* nada */;
 108        if (buf >= tail)
 109                return 0;
 110        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 111        return strtoul(dateptr, NULL, 10);
 112}
 113
 114static struct commit_graft **commit_graft;
 115static int commit_graft_alloc, commit_graft_nr;
 116
 117static int commit_graft_pos(const unsigned char *sha1)
 118{
 119        int lo, hi;
 120        lo = 0;
 121        hi = commit_graft_nr;
 122        while (lo < hi) {
 123                int mi = (lo + hi) / 2;
 124                struct commit_graft *graft = commit_graft[mi];
 125                int cmp = hashcmp(sha1, graft->sha1);
 126                if (!cmp)
 127                        return mi;
 128                if (cmp < 0)
 129                        hi = mi;
 130                else
 131                        lo = mi + 1;
 132        }
 133        return -lo - 1;
 134}
 135
 136int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 137{
 138        int pos = commit_graft_pos(graft->sha1);
 139
 140        if (0 <= pos) {
 141                if (ignore_dups)
 142                        free(graft);
 143                else {
 144                        free(commit_graft[pos]);
 145                        commit_graft[pos] = graft;
 146                }
 147                return 1;
 148        }
 149        pos = -pos - 1;
 150        if (commit_graft_alloc <= ++commit_graft_nr) {
 151                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 152                commit_graft = xrealloc(commit_graft,
 153                                        sizeof(*commit_graft) *
 154                                        commit_graft_alloc);
 155        }
 156        if (pos < commit_graft_nr)
 157                memmove(commit_graft + pos + 1,
 158                        commit_graft + pos,
 159                        (commit_graft_nr - pos - 1) *
 160                        sizeof(*commit_graft));
 161        commit_graft[pos] = graft;
 162        return 0;
 163}
 164
 165struct commit_graft *read_graft_line(char *buf, int len)
 166{
 167        /* The format is just "Commit Parent1 Parent2 ...\n" */
 168        int i;
 169        struct commit_graft *graft = NULL;
 170
 171        while (len && isspace(buf[len-1]))
 172                buf[--len] = '\0';
 173        if (buf[0] == '#' || buf[0] == '\0')
 174                return NULL;
 175        if ((len + 1) % 41)
 176                goto bad_graft_data;
 177        i = (len + 1) / 41 - 1;
 178        graft = xmalloc(sizeof(*graft) + 20 * i);
 179        graft->nr_parent = i;
 180        if (get_sha1_hex(buf, graft->sha1))
 181                goto bad_graft_data;
 182        for (i = 40; i < len; i += 41) {
 183                if (buf[i] != ' ')
 184                        goto bad_graft_data;
 185                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 186                        goto bad_graft_data;
 187        }
 188        return graft;
 189
 190bad_graft_data:
 191        error("bad graft data: %s", buf);
 192        free(graft);
 193        return NULL;
 194}
 195
 196static int read_graft_file(const char *graft_file)
 197{
 198        FILE *fp = fopen(graft_file, "r");
 199        char buf[1024];
 200        if (!fp)
 201                return -1;
 202        while (fgets(buf, sizeof(buf), fp)) {
 203                /* The format is just "Commit Parent1 Parent2 ...\n" */
 204                int len = strlen(buf);
 205                struct commit_graft *graft = read_graft_line(buf, len);
 206                if (!graft)
 207                        continue;
 208                if (register_commit_graft(graft, 1))
 209                        error("duplicate graft data: %s", buf);
 210        }
 211        fclose(fp);
 212        return 0;
 213}
 214
 215static void prepare_commit_graft(void)
 216{
 217        static int commit_graft_prepared;
 218        char *graft_file;
 219
 220        if (commit_graft_prepared)
 221                return;
 222        graft_file = get_graft_file();
 223        read_graft_file(graft_file);
 224        /* make sure shallows are read */
 225        is_repository_shallow();
 226        commit_graft_prepared = 1;
 227}
 228
 229struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 230{
 231        int pos;
 232        prepare_commit_graft();
 233        pos = commit_graft_pos(sha1);
 234        if (pos < 0)
 235                return NULL;
 236        return commit_graft[pos];
 237}
 238
 239int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 240{
 241        int i, ret;
 242        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 243                ret = fn(commit_graft[i], cb_data);
 244        return ret;
 245}
 246
 247int unregister_shallow(const unsigned char *sha1)
 248{
 249        int pos = commit_graft_pos(sha1);
 250        if (pos < 0)
 251                return -1;
 252        if (pos + 1 < commit_graft_nr)
 253                memmove(commit_graft + pos, commit_graft + pos + 1,
 254                                sizeof(struct commit_graft *)
 255                                * (commit_graft_nr - pos - 1));
 256        commit_graft_nr--;
 257        return 0;
 258}
 259
 260int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 261{
 262        const char *tail = buffer;
 263        const char *bufptr = buffer;
 264        unsigned char parent[20];
 265        struct commit_list **pptr;
 266        struct commit_graft *graft;
 267
 268        if (item->object.parsed)
 269                return 0;
 270        item->object.parsed = 1;
 271        tail += size;
 272        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 273                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 274        if (get_sha1_hex(bufptr + 5, parent) < 0)
 275                return error("bad tree pointer in commit %s",
 276                             sha1_to_hex(item->object.sha1));
 277        item->tree = lookup_tree(parent);
 278        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 279        pptr = &item->parents;
 280
 281        graft = lookup_commit_graft(item->object.sha1);
 282        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 283                struct commit *new_parent;
 284
 285                if (tail <= bufptr + 48 ||
 286                    get_sha1_hex(bufptr + 7, parent) ||
 287                    bufptr[47] != '\n')
 288                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 289                bufptr += 48;
 290                /*
 291                 * The clone is shallow if nr_parent < 0, and we must
 292                 * not traverse its real parents even when we unhide them.
 293                 */
 294                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 295                        continue;
 296                new_parent = lookup_commit(parent);
 297                if (new_parent)
 298                        pptr = &commit_list_insert(new_parent, pptr)->next;
 299        }
 300        if (graft) {
 301                int i;
 302                struct commit *new_parent;
 303                for (i = 0; i < graft->nr_parent; i++) {
 304                        new_parent = lookup_commit(graft->parent[i]);
 305                        if (!new_parent)
 306                                continue;
 307                        pptr = &commit_list_insert(new_parent, pptr)->next;
 308                }
 309        }
 310        item->date = parse_commit_date(bufptr, tail);
 311
 312        return 0;
 313}
 314
 315int parse_commit(struct commit *item)
 316{
 317        enum object_type type;
 318        void *buffer;
 319        unsigned long size;
 320        int ret;
 321
 322        if (!item)
 323                return -1;
 324        if (item->object.parsed)
 325                return 0;
 326        buffer = read_sha1_file(item->object.sha1, &type, &size);
 327        if (!buffer)
 328                return error("Could not read %s",
 329                             sha1_to_hex(item->object.sha1));
 330        if (type != OBJ_COMMIT) {
 331                free(buffer);
 332                return error("Object %s not a commit",
 333                             sha1_to_hex(item->object.sha1));
 334        }
 335        ret = parse_commit_buffer(item, buffer, size);
 336        if (save_commit_buffer && !ret) {
 337                item->buffer = buffer;
 338                return 0;
 339        }
 340        free(buffer);
 341        return ret;
 342}
 343
 344void parse_commit_or_die(struct commit *item)
 345{
 346        if (parse_commit(item))
 347                die("unable to parse commit %s",
 348                    item ? sha1_to_hex(item->object.sha1) : "(null)");
 349}
 350
 351int find_commit_subject(const char *commit_buffer, const char **subject)
 352{
 353        const char *eol;
 354        const char *p = commit_buffer;
 355
 356        while (*p && (*p != '\n' || p[1] != '\n'))
 357                p++;
 358        if (*p) {
 359                p += 2;
 360                for (eol = p; *eol && *eol != '\n'; eol++)
 361                        ; /* do nothing */
 362        } else
 363                eol = p;
 364
 365        *subject = p;
 366
 367        return eol - p;
 368}
 369
 370struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 371{
 372        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 373        new_list->item = item;
 374        new_list->next = *list_p;
 375        *list_p = new_list;
 376        return new_list;
 377}
 378
 379unsigned 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
 387void 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
 396struct 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
 409static 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
 420static void *commit_list_get_next(const void *a)
 421{
 422        return ((const struct commit_list *)a)->next;
 423}
 424
 425static void commit_list_set_next(void *a, void *next)
 426{
 427        ((struct commit_list *)a)->next = next;
 428}
 429
 430void commit_list_sort_by_date(struct commit_list **list)
 431{
 432        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 433                                commit_list_compare_by_date);
 434}
 435
 436struct 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
 457static void clear_commit_marks_1(struct commit_list **plist,
 458                                 struct commit *commit, unsigned int mark)
 459{
 460        while (commit) {
 461                struct commit_list *parents;
 462
 463                if (!(mark & commit->object.flags))
 464                        return;
 465
 466                commit->object.flags &= ~mark;
 467
 468                parents = commit->parents;
 469                if (!parents)
 470                        return;
 471
 472                while ((parents = parents->next))
 473                        commit_list_insert(parents->item, plist);
 474
 475                commit = commit->parents->item;
 476        }
 477}
 478
 479void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 480{
 481        struct commit_list *list = NULL;
 482
 483        while (nr--) {
 484                commit_list_insert(*commit, &list);
 485                commit++;
 486        }
 487        while (list)
 488                clear_commit_marks_1(&list, pop_commit(&list), mark);
 489}
 490
 491void clear_commit_marks(struct commit *commit, unsigned int mark)
 492{
 493        clear_commit_marks_many(1, &commit, mark);
 494}
 495
 496void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 497{
 498        struct object *object;
 499        struct commit *commit;
 500        unsigned int i;
 501
 502        for (i = 0; i < a->nr; i++) {
 503                object = a->objects[i].item;
 504                commit = lookup_commit_reference_gently(object->sha1, 1);
 505                if (commit)
 506                        clear_commit_marks(commit, mark);
 507        }
 508}
 509
 510struct commit *pop_commit(struct commit_list **stack)
 511{
 512        struct commit_list *top = *stack;
 513        struct commit *item = top ? top->item : NULL;
 514
 515        if (top) {
 516                *stack = top->next;
 517                free(top);
 518        }
 519        return item;
 520}
 521
 522/*
 523 * Topological sort support
 524 */
 525
 526/* count number of children that have not been emitted */
 527define_commit_slab(indegree_slab, int);
 528
 529/* record author-date for each commit object */
 530define_commit_slab(author_date_slab, unsigned long);
 531
 532static void record_author_date(struct author_date_slab *author_date,
 533                               struct commit *commit)
 534{
 535        const char *buf, *line_end;
 536        char *buffer = NULL;
 537        struct ident_split ident;
 538        char *date_end;
 539        unsigned long date;
 540
 541        if (!commit->buffer) {
 542                unsigned long size;
 543                enum object_type type;
 544                buffer = read_sha1_file(commit->object.sha1, &type, &size);
 545                if (!buffer)
 546                        return;
 547        }
 548
 549        for (buf = commit->buffer ? commit->buffer : buffer;
 550             buf;
 551             buf = line_end + 1) {
 552                line_end = strchrnul(buf, '\n');
 553                if (prefixcmp(buf, "author ")) {
 554                        if (!line_end[0] || line_end[1] == '\n')
 555                                return; /* end of header */
 556                        continue;
 557                }
 558                if (split_ident_line(&ident,
 559                                     buf + strlen("author "),
 560                                     line_end - (buf + strlen("author "))) ||
 561                    !ident.date_begin || !ident.date_end)
 562                        goto fail_exit; /* malformed "author" line */
 563                break;
 564        }
 565
 566        date = strtoul(ident.date_begin, &date_end, 10);
 567        if (date_end != ident.date_end)
 568                goto fail_exit; /* malformed date */
 569        *(author_date_slab_at(author_date, commit)) = date;
 570
 571fail_exit:
 572        free(buffer);
 573}
 574
 575static int compare_commits_by_author_date(const void *a_, const void *b_,
 576                                          void *cb_data)
 577{
 578        const struct commit *a = a_, *b = b_;
 579        struct author_date_slab *author_date = cb_data;
 580        unsigned long a_date = *(author_date_slab_at(author_date, a));
 581        unsigned long b_date = *(author_date_slab_at(author_date, b));
 582
 583        /* newer commits with larger date first */
 584        if (a_date < b_date)
 585                return 1;
 586        else if (a_date > b_date)
 587                return -1;
 588        return 0;
 589}
 590
 591int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 592{
 593        const struct commit *a = a_, *b = b_;
 594        /* newer commits with larger date first */
 595        if (a->date < b->date)
 596                return 1;
 597        else if (a->date > b->date)
 598                return -1;
 599        return 0;
 600}
 601
 602/*
 603 * Performs an in-place topological sort on the list supplied.
 604 */
 605void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 606{
 607        struct commit_list *next, *orig = *list;
 608        struct commit_list **pptr;
 609        struct indegree_slab indegree;
 610        struct prio_queue queue;
 611        struct commit *commit;
 612        struct author_date_slab author_date;
 613
 614        if (!orig)
 615                return;
 616        *list = NULL;
 617
 618        init_indegree_slab(&indegree);
 619        memset(&queue, '\0', sizeof(queue));
 620
 621        switch (sort_order) {
 622        default: /* REV_SORT_IN_GRAPH_ORDER */
 623                queue.compare = NULL;
 624                break;
 625        case REV_SORT_BY_COMMIT_DATE:
 626                queue.compare = compare_commits_by_commit_date;
 627                break;
 628        case REV_SORT_BY_AUTHOR_DATE:
 629                init_author_date_slab(&author_date);
 630                queue.compare = compare_commits_by_author_date;
 631                queue.cb_data = &author_date;
 632                break;
 633        }
 634
 635        /* Mark them and clear the indegree */
 636        for (next = orig; next; next = next->next) {
 637                struct commit *commit = next->item;
 638                *(indegree_slab_at(&indegree, commit)) = 1;
 639                /* also record the author dates, if needed */
 640                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 641                        record_author_date(&author_date, commit);
 642        }
 643
 644        /* update the indegree */
 645        for (next = orig; next; next = next->next) {
 646                struct commit_list *parents = next->item->parents;
 647                while (parents) {
 648                        struct commit *parent = parents->item;
 649                        int *pi = indegree_slab_at(&indegree, parent);
 650
 651                        if (*pi)
 652                                (*pi)++;
 653                        parents = parents->next;
 654                }
 655        }
 656
 657        /*
 658         * find the tips
 659         *
 660         * tips are nodes not reachable from any other node in the list
 661         *
 662         * the tips serve as a starting set for the work queue.
 663         */
 664        for (next = orig; next; next = next->next) {
 665                struct commit *commit = next->item;
 666
 667                if (*(indegree_slab_at(&indegree, commit)) == 1)
 668                        prio_queue_put(&queue, commit);
 669        }
 670
 671        /*
 672         * This is unfortunate; the initial tips need to be shown
 673         * in the order given from the revision traversal machinery.
 674         */
 675        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 676                prio_queue_reverse(&queue);
 677
 678        /* We no longer need the commit list */
 679        free_commit_list(orig);
 680
 681        pptr = list;
 682        *list = NULL;
 683        while ((commit = prio_queue_get(&queue)) != NULL) {
 684                struct commit_list *parents;
 685
 686                for (parents = commit->parents; parents ; parents = parents->next) {
 687                        struct commit *parent = parents->item;
 688                        int *pi = indegree_slab_at(&indegree, parent);
 689
 690                        if (!*pi)
 691                                continue;
 692
 693                        /*
 694                         * parents are only enqueued for emission
 695                         * when all their children have been emitted thereby
 696                         * guaranteeing topological order.
 697                         */
 698                        if (--(*pi) == 1)
 699                                prio_queue_put(&queue, parent);
 700                }
 701                /*
 702                 * all children of commit have already been
 703                 * emitted. we can emit it now.
 704                 */
 705                *(indegree_slab_at(&indegree, commit)) = 0;
 706
 707                pptr = &commit_list_insert(commit, pptr)->next;
 708        }
 709
 710        clear_indegree_slab(&indegree);
 711        clear_prio_queue(&queue);
 712        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 713                clear_author_date_slab(&author_date);
 714}
 715
 716/* merge-base stuff */
 717
 718/* bits #0..15 in revision.h */
 719#define PARENT1         (1u<<16)
 720#define PARENT2         (1u<<17)
 721#define STALE           (1u<<18)
 722#define RESULT          (1u<<19)
 723
 724static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 725
 726static struct commit *interesting(struct commit_list *list)
 727{
 728        while (list) {
 729                struct commit *commit = list->item;
 730                list = list->next;
 731                if (commit->object.flags & STALE)
 732                        continue;
 733                return commit;
 734        }
 735        return NULL;
 736}
 737
 738/* all input commits in one and twos[] must have been parsed! */
 739static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 740{
 741        struct commit_list *list = NULL;
 742        struct commit_list *result = NULL;
 743        int i;
 744
 745        one->object.flags |= PARENT1;
 746        commit_list_insert_by_date(one, &list);
 747        if (!n)
 748                return list;
 749        for (i = 0; i < n; i++) {
 750                twos[i]->object.flags |= PARENT2;
 751                commit_list_insert_by_date(twos[i], &list);
 752        }
 753
 754        while (interesting(list)) {
 755                struct commit *commit;
 756                struct commit_list *parents;
 757                struct commit_list *next;
 758                int flags;
 759
 760                commit = list->item;
 761                next = list->next;
 762                free(list);
 763                list = next;
 764
 765                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 766                if (flags == (PARENT1 | PARENT2)) {
 767                        if (!(commit->object.flags & RESULT)) {
 768                                commit->object.flags |= RESULT;
 769                                commit_list_insert_by_date(commit, &result);
 770                        }
 771                        /* Mark parents of a found merge stale */
 772                        flags |= STALE;
 773                }
 774                parents = commit->parents;
 775                while (parents) {
 776                        struct commit *p = parents->item;
 777                        parents = parents->next;
 778                        if ((p->object.flags & flags) == flags)
 779                                continue;
 780                        if (parse_commit(p))
 781                                return NULL;
 782                        p->object.flags |= flags;
 783                        commit_list_insert_by_date(p, &list);
 784                }
 785        }
 786
 787        free_commit_list(list);
 788        return result;
 789}
 790
 791static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 792{
 793        struct commit_list *list = NULL;
 794        struct commit_list *result = NULL;
 795        int i;
 796
 797        for (i = 0; i < n; i++) {
 798                if (one == twos[i])
 799                        /*
 800                         * We do not mark this even with RESULT so we do not
 801                         * have to clean it up.
 802                         */
 803                        return commit_list_insert(one, &result);
 804        }
 805
 806        if (parse_commit(one))
 807                return NULL;
 808        for (i = 0; i < n; i++) {
 809                if (parse_commit(twos[i]))
 810                        return NULL;
 811        }
 812
 813        list = paint_down_to_common(one, n, twos);
 814
 815        while (list) {
 816                struct commit_list *next = list->next;
 817                if (!(list->item->object.flags & STALE))
 818                        commit_list_insert_by_date(list->item, &result);
 819                free(list);
 820                list = next;
 821        }
 822        return result;
 823}
 824
 825struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 826{
 827        struct commit_list *i, *j, *k, *ret = NULL;
 828        struct commit_list **pptr = &ret;
 829
 830        for (i = in; i; i = i->next) {
 831                if (!ret)
 832                        pptr = &commit_list_insert(i->item, pptr)->next;
 833                else {
 834                        struct commit_list *new = NULL, *end = NULL;
 835
 836                        for (j = ret; j; j = j->next) {
 837                                struct commit_list *bases;
 838                                bases = get_merge_bases(i->item, j->item, 1);
 839                                if (!new)
 840                                        new = bases;
 841                                else
 842                                        end->next = bases;
 843                                for (k = bases; k; k = k->next)
 844                                        end = k;
 845                        }
 846                        ret = new;
 847                }
 848        }
 849        return ret;
 850}
 851
 852static int remove_redundant(struct commit **array, int cnt)
 853{
 854        /*
 855         * Some commit in the array may be an ancestor of
 856         * another commit.  Move such commit to the end of
 857         * the array, and return the number of commits that
 858         * are independent from each other.
 859         */
 860        struct commit **work;
 861        unsigned char *redundant;
 862        int *filled_index;
 863        int i, j, filled;
 864
 865        work = xcalloc(cnt, sizeof(*work));
 866        redundant = xcalloc(cnt, 1);
 867        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 868
 869        for (i = 0; i < cnt; i++)
 870                parse_commit(array[i]);
 871        for (i = 0; i < cnt; i++) {
 872                struct commit_list *common;
 873
 874                if (redundant[i])
 875                        continue;
 876                for (j = filled = 0; j < cnt; j++) {
 877                        if (i == j || redundant[j])
 878                                continue;
 879                        filled_index[filled] = j;
 880                        work[filled++] = array[j];
 881                }
 882                common = paint_down_to_common(array[i], filled, work);
 883                if (array[i]->object.flags & PARENT2)
 884                        redundant[i] = 1;
 885                for (j = 0; j < filled; j++)
 886                        if (work[j]->object.flags & PARENT1)
 887                                redundant[filled_index[j]] = 1;
 888                clear_commit_marks(array[i], all_flags);
 889                for (j = 0; j < filled; j++)
 890                        clear_commit_marks(work[j], all_flags);
 891                free_commit_list(common);
 892        }
 893
 894        /* Now collect the result */
 895        memcpy(work, array, sizeof(*array) * cnt);
 896        for (i = filled = 0; i < cnt; i++)
 897                if (!redundant[i])
 898                        array[filled++] = work[i];
 899        for (j = filled, i = 0; i < cnt; i++)
 900                if (redundant[i])
 901                        array[j++] = work[i];
 902        free(work);
 903        free(redundant);
 904        free(filled_index);
 905        return filled;
 906}
 907
 908struct commit_list *get_merge_bases_many(struct commit *one,
 909                                         int n,
 910                                         struct commit **twos,
 911                                         int cleanup)
 912{
 913        struct commit_list *list;
 914        struct commit **rslt;
 915        struct commit_list *result;
 916        int cnt, i;
 917
 918        result = merge_bases_many(one, n, twos);
 919        for (i = 0; i < n; i++) {
 920                if (one == twos[i])
 921                        return result;
 922        }
 923        if (!result || !result->next) {
 924                if (cleanup) {
 925                        clear_commit_marks(one, all_flags);
 926                        clear_commit_marks_many(n, twos, all_flags);
 927                }
 928                return result;
 929        }
 930
 931        /* There are more than one */
 932        cnt = 0;
 933        list = result;
 934        while (list) {
 935                list = list->next;
 936                cnt++;
 937        }
 938        rslt = xcalloc(cnt, sizeof(*rslt));
 939        for (list = result, i = 0; list; list = list->next)
 940                rslt[i++] = list->item;
 941        free_commit_list(result);
 942
 943        clear_commit_marks(one, all_flags);
 944        clear_commit_marks_many(n, twos, all_flags);
 945
 946        cnt = remove_redundant(rslt, cnt);
 947        result = NULL;
 948        for (i = 0; i < cnt; i++)
 949                commit_list_insert_by_date(rslt[i], &result);
 950        free(rslt);
 951        return result;
 952}
 953
 954struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 955                                    int cleanup)
 956{
 957        return get_merge_bases_many(one, 1, &two, cleanup);
 958}
 959
 960/*
 961 * Is "commit" a descendant of one of the elements on the "with_commit" list?
 962 */
 963int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 964{
 965        if (!with_commit)
 966                return 1;
 967        while (with_commit) {
 968                struct commit *other;
 969
 970                other = with_commit->item;
 971                with_commit = with_commit->next;
 972                if (in_merge_bases(other, commit))
 973                        return 1;
 974        }
 975        return 0;
 976}
 977
 978/*
 979 * Is "commit" an ancestor of one of the "references"?
 980 */
 981int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 982{
 983        struct commit_list *bases;
 984        int ret = 0, i;
 985
 986        if (parse_commit(commit))
 987                return ret;
 988        for (i = 0; i < nr_reference; i++)
 989                if (parse_commit(reference[i]))
 990                        return ret;
 991
 992        bases = paint_down_to_common(commit, nr_reference, reference);
 993        if (commit->object.flags & PARENT2)
 994                ret = 1;
 995        clear_commit_marks(commit, all_flags);
 996        clear_commit_marks_many(nr_reference, reference, all_flags);
 997        free_commit_list(bases);
 998        return ret;
 999}
1000
1001/*
1002 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1003 */
1004int in_merge_bases(struct commit *commit, struct commit *reference)
1005{
1006        return in_merge_bases_many(commit, 1, &reference);
1007}
1008
1009struct commit_list *reduce_heads(struct commit_list *heads)
1010{
1011        struct commit_list *p;
1012        struct commit_list *result = NULL, **tail = &result;
1013        struct commit **array;
1014        int num_head, i;
1015
1016        if (!heads)
1017                return NULL;
1018
1019        /* Uniquify */
1020        for (p = heads; p; p = p->next)
1021                p->item->object.flags &= ~STALE;
1022        for (p = heads, num_head = 0; p; p = p->next) {
1023                if (p->item->object.flags & STALE)
1024                        continue;
1025                p->item->object.flags |= STALE;
1026                num_head++;
1027        }
1028        array = xcalloc(sizeof(*array), num_head);
1029        for (p = heads, i = 0; p; p = p->next) {
1030                if (p->item->object.flags & STALE) {
1031                        array[i++] = p->item;
1032                        p->item->object.flags &= ~STALE;
1033                }
1034        }
1035        num_head = remove_redundant(array, num_head);
1036        for (i = 0; i < num_head; i++)
1037                tail = &commit_list_insert(array[i], tail)->next;
1038        return result;
1039}
1040
1041static const char gpg_sig_header[] = "gpgsig";
1042static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1043
1044static int do_sign_commit(struct strbuf *buf, const char *keyid)
1045{
1046        struct strbuf sig = STRBUF_INIT;
1047        int inspos, copypos;
1048
1049        /* find the end of the header */
1050        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1051
1052        if (!keyid || !*keyid)
1053                keyid = get_signing_key();
1054        if (sign_buffer(buf, &sig, keyid)) {
1055                strbuf_release(&sig);
1056                return -1;
1057        }
1058
1059        for (copypos = 0; sig.buf[copypos]; ) {
1060                const char *bol = sig.buf + copypos;
1061                const char *eol = strchrnul(bol, '\n');
1062                int len = (eol - bol) + !!*eol;
1063
1064                if (!copypos) {
1065                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1066                        inspos += gpg_sig_header_len;
1067                }
1068                strbuf_insert(buf, inspos++, " ", 1);
1069                strbuf_insert(buf, inspos, bol, len);
1070                inspos += len;
1071                copypos += len;
1072        }
1073        strbuf_release(&sig);
1074        return 0;
1075}
1076
1077int parse_signed_commit(const unsigned char *sha1,
1078                        struct strbuf *payload, struct strbuf *signature)
1079{
1080        unsigned long size;
1081        enum object_type type;
1082        char *buffer = read_sha1_file(sha1, &type, &size);
1083        int in_signature, saw_signature = -1;
1084        char *line, *tail;
1085
1086        if (!buffer || type != OBJ_COMMIT)
1087                goto cleanup;
1088
1089        line = buffer;
1090        tail = buffer + size;
1091        in_signature = 0;
1092        saw_signature = 0;
1093        while (line < tail) {
1094                const char *sig = NULL;
1095                char *next = memchr(line, '\n', tail - line);
1096
1097                next = next ? next + 1 : tail;
1098                if (in_signature && line[0] == ' ')
1099                        sig = line + 1;
1100                else if (!prefixcmp(line, gpg_sig_header) &&
1101                         line[gpg_sig_header_len] == ' ')
1102                        sig = line + gpg_sig_header_len + 1;
1103                if (sig) {
1104                        strbuf_add(signature, sig, next - sig);
1105                        saw_signature = 1;
1106                        in_signature = 1;
1107                } else {
1108                        if (*line == '\n')
1109                                /* dump the whole remainder of the buffer */
1110                                next = tail;
1111                        strbuf_add(payload, line, next - line);
1112                        in_signature = 0;
1113                }
1114                line = next;
1115        }
1116 cleanup:
1117        free(buffer);
1118        return saw_signature;
1119}
1120
1121static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1122{
1123        struct merge_remote_desc *desc;
1124        struct commit_extra_header *mergetag;
1125        char *buf;
1126        unsigned long size, len;
1127        enum object_type type;
1128
1129        desc = merge_remote_util(parent);
1130        if (!desc || !desc->obj)
1131                return;
1132        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1133        if (!buf || type != OBJ_TAG)
1134                goto free_return;
1135        len = parse_signature(buf, size);
1136        if (size == len)
1137                goto free_return;
1138        /*
1139         * We could verify this signature and either omit the tag when
1140         * it does not validate, but the integrator may not have the
1141         * public key of the signer of the tag he is merging, while a
1142         * later auditor may have it while auditing, so let's not run
1143         * verify-signed-buffer here for now...
1144         *
1145         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1146         *      warn("warning: signed tag unverified.");
1147         */
1148        mergetag = xcalloc(1, sizeof(*mergetag));
1149        mergetag->key = xstrdup("mergetag");
1150        mergetag->value = buf;
1151        mergetag->len = size;
1152
1153        **tail = mergetag;
1154        *tail = &mergetag->next;
1155        return;
1156
1157free_return:
1158        free(buf);
1159}
1160
1161static struct {
1162        char result;
1163        const char *check;
1164} sigcheck_gpg_status[] = {
1165        { 'G', "\n[GNUPG:] GOODSIG " },
1166        { 'B', "\n[GNUPG:] BADSIG " },
1167        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1168        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1169};
1170
1171static void parse_gpg_output(struct signature_check *sigc)
1172{
1173        const char *buf = sigc->gpg_status;
1174        int i;
1175
1176        /* Iterate over all search strings */
1177        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1178                const char *found, *next;
1179
1180                if (!prefixcmp(buf, sigcheck_gpg_status[i].check + 1)) {
1181                        /* At the very beginning of the buffer */
1182                        found = buf + strlen(sigcheck_gpg_status[i].check + 1);
1183                } else {
1184                        found = strstr(buf, sigcheck_gpg_status[i].check);
1185                        if (!found)
1186                                continue;
1187                        found += strlen(sigcheck_gpg_status[i].check);
1188                }
1189                sigc->result = sigcheck_gpg_status[i].result;
1190                /* The trust messages are not followed by key/signer information */
1191                if (sigc->result != 'U') {
1192                        sigc->key = xmemdupz(found, 16);
1193                        found += 17;
1194                        next = strchrnul(found, '\n');
1195                        sigc->signer = xmemdupz(found, next - found);
1196                }
1197        }
1198}
1199
1200void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1201{
1202        struct strbuf payload = STRBUF_INIT;
1203        struct strbuf signature = STRBUF_INIT;
1204        struct strbuf gpg_output = STRBUF_INIT;
1205        struct strbuf gpg_status = STRBUF_INIT;
1206        int status;
1207
1208        sigc->result = 'N';
1209
1210        if (parse_signed_commit(commit->object.sha1,
1211                                &payload, &signature) <= 0)
1212                goto out;
1213        status = verify_signed_buffer(payload.buf, payload.len,
1214                                      signature.buf, signature.len,
1215                                      &gpg_output, &gpg_status);
1216        if (status && !gpg_output.len)
1217                goto out;
1218        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1219        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1220        parse_gpg_output(sigc);
1221
1222 out:
1223        strbuf_release(&gpg_status);
1224        strbuf_release(&gpg_output);
1225        strbuf_release(&payload);
1226        strbuf_release(&signature);
1227}
1228
1229
1230
1231void append_merge_tag_headers(struct commit_list *parents,
1232                              struct commit_extra_header ***tail)
1233{
1234        while (parents) {
1235                struct commit *parent = parents->item;
1236                handle_signed_tag(parent, tail);
1237                parents = parents->next;
1238        }
1239}
1240
1241static void add_extra_header(struct strbuf *buffer,
1242                             struct commit_extra_header *extra)
1243{
1244        strbuf_addstr(buffer, extra->key);
1245        if (extra->len)
1246                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1247        else
1248                strbuf_addch(buffer, '\n');
1249}
1250
1251struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1252                                                      const char **exclude)
1253{
1254        struct commit_extra_header *extra = NULL;
1255        unsigned long size;
1256        enum object_type type;
1257        char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1258        if (buffer && type == OBJ_COMMIT)
1259                extra = read_commit_extra_header_lines(buffer, size, exclude);
1260        free(buffer);
1261        return extra;
1262}
1263
1264static inline int standard_header_field(const char *field, size_t len)
1265{
1266        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1267                (len == 6 && !memcmp(field, "parent ", 7)) ||
1268                (len == 6 && !memcmp(field, "author ", 7)) ||
1269                (len == 9 && !memcmp(field, "committer ", 10)) ||
1270                (len == 8 && !memcmp(field, "encoding ", 9)));
1271}
1272
1273static int excluded_header_field(const char *field, size_t len, const char **exclude)
1274{
1275        if (!exclude)
1276                return 0;
1277
1278        while (*exclude) {
1279                size_t xlen = strlen(*exclude);
1280                if (len == xlen &&
1281                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1282                        return 1;
1283                exclude++;
1284        }
1285        return 0;
1286}
1287
1288static struct commit_extra_header *read_commit_extra_header_lines(
1289        const char *buffer, size_t size,
1290        const char **exclude)
1291{
1292        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1293        const char *line, *next, *eof, *eob;
1294        struct strbuf buf = STRBUF_INIT;
1295
1296        for (line = buffer, eob = line + size;
1297             line < eob && *line != '\n';
1298             line = next) {
1299                next = memchr(line, '\n', eob - line);
1300                next = next ? next + 1 : eob;
1301                if (*line == ' ') {
1302                        /* continuation */
1303                        if (it)
1304                                strbuf_add(&buf, line + 1, next - (line + 1));
1305                        continue;
1306                }
1307                if (it)
1308                        it->value = strbuf_detach(&buf, &it->len);
1309                strbuf_reset(&buf);
1310                it = NULL;
1311
1312                eof = strchr(line, ' ');
1313                if (next <= eof)
1314                        eof = next;
1315
1316                if (standard_header_field(line, eof - line) ||
1317                    excluded_header_field(line, eof - line, exclude))
1318                        continue;
1319
1320                it = xcalloc(1, sizeof(*it));
1321                it->key = xmemdupz(line, eof-line);
1322                *tail = it;
1323                tail = &it->next;
1324                if (eof + 1 < next)
1325                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1326        }
1327        if (it)
1328                it->value = strbuf_detach(&buf, &it->len);
1329        return extra;
1330}
1331
1332void free_commit_extra_headers(struct commit_extra_header *extra)
1333{
1334        while (extra) {
1335                struct commit_extra_header *next = extra->next;
1336                free(extra->key);
1337                free(extra->value);
1338                free(extra);
1339                extra = next;
1340        }
1341}
1342
1343int commit_tree(const struct strbuf *msg, unsigned char *tree,
1344                struct commit_list *parents, unsigned char *ret,
1345                const char *author, const char *sign_commit)
1346{
1347        struct commit_extra_header *extra = NULL, **tail = &extra;
1348        int result;
1349
1350        append_merge_tag_headers(parents, &tail);
1351        result = commit_tree_extended(msg, tree, parents, ret,
1352                                      author, sign_commit, extra);
1353        free_commit_extra_headers(extra);
1354        return result;
1355}
1356
1357static int find_invalid_utf8(const char *buf, int len)
1358{
1359        int offset = 0;
1360        static const unsigned int max_codepoint[] = {
1361                0x7f, 0x7ff, 0xffff, 0x10ffff
1362        };
1363
1364        while (len) {
1365                unsigned char c = *buf++;
1366                int bytes, bad_offset;
1367                unsigned int codepoint;
1368                unsigned int min_val, max_val;
1369
1370                len--;
1371                offset++;
1372
1373                /* Simple US-ASCII? No worries. */
1374                if (c < 0x80)
1375                        continue;
1376
1377                bad_offset = offset-1;
1378
1379                /*
1380                 * Count how many more high bits set: that's how
1381                 * many more bytes this sequence should have.
1382                 */
1383                bytes = 0;
1384                while (c & 0x40) {
1385                        c <<= 1;
1386                        bytes++;
1387                }
1388
1389                /*
1390                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1391                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1392                 */
1393                if (bytes < 1 || 3 < bytes)
1394                        return bad_offset;
1395
1396                /* Do we *have* that many bytes? */
1397                if (len < bytes)
1398                        return bad_offset;
1399
1400                /*
1401                 * Place the encoded bits at the bottom of the value and compute the
1402                 * valid range.
1403                 */
1404                codepoint = (c & 0x7f) >> bytes;
1405                min_val = max_codepoint[bytes-1] + 1;
1406                max_val = max_codepoint[bytes];
1407
1408                offset += bytes;
1409                len -= bytes;
1410
1411                /* And verify that they are good continuation bytes */
1412                do {
1413                        codepoint <<= 6;
1414                        codepoint |= *buf & 0x3f;
1415                        if ((*buf++ & 0xc0) != 0x80)
1416                                return bad_offset;
1417                } while (--bytes);
1418
1419                /* Reject codepoints that are out of range for the sequence length. */
1420                if (codepoint < min_val || codepoint > max_val)
1421                        return bad_offset;
1422                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1423                if ((codepoint & 0x1ff800) == 0xd800)
1424                        return bad_offset;
1425                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1426                if ((codepoint & 0xfffe) == 0xfffe)
1427                        return bad_offset;
1428                /* So are anything in the range U+FDD0..U+FDEF. */
1429                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1430                        return bad_offset;
1431        }
1432        return -1;
1433}
1434
1435/*
1436 * This verifies that the buffer is in proper utf8 format.
1437 *
1438 * If it isn't, it assumes any non-utf8 characters are Latin1,
1439 * and does the conversion.
1440 */
1441static int verify_utf8(struct strbuf *buf)
1442{
1443        int ok = 1;
1444        long pos = 0;
1445
1446        for (;;) {
1447                int bad;
1448                unsigned char c;
1449                unsigned char replace[2];
1450
1451                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1452                if (bad < 0)
1453                        return ok;
1454                pos += bad;
1455                ok = 0;
1456                c = buf->buf[pos];
1457                strbuf_remove(buf, pos, 1);
1458
1459                /* We know 'c' must be in the range 128-255 */
1460                replace[0] = 0xc0 + (c >> 6);
1461                replace[1] = 0x80 + (c & 0x3f);
1462                strbuf_insert(buf, pos, replace, 2);
1463                pos += 2;
1464        }
1465}
1466
1467static const char commit_utf8_warn[] =
1468"Warning: commit message did not conform to UTF-8.\n"
1469"You may want to amend it after fixing the message, or set the config\n"
1470"variable i18n.commitencoding to the encoding your project uses.\n";
1471
1472int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1473                         struct commit_list *parents, unsigned char *ret,
1474                         const char *author, const char *sign_commit,
1475                         struct commit_extra_header *extra)
1476{
1477        int result;
1478        int encoding_is_utf8;
1479        struct strbuf buffer;
1480
1481        assert_sha1_type(tree, OBJ_TREE);
1482
1483        if (memchr(msg->buf, '\0', msg->len))
1484                return error("a NUL byte in commit log message not allowed.");
1485
1486        /* Not having i18n.commitencoding is the same as having utf-8 */
1487        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1488
1489        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1490        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1491
1492        /*
1493         * NOTE! This ordering means that the same exact tree merged with a
1494         * different order of parents will be a _different_ changeset even
1495         * if everything else stays the same.
1496         */
1497        while (parents) {
1498                struct commit_list *next = parents->next;
1499                struct commit *parent = parents->item;
1500
1501                strbuf_addf(&buffer, "parent %s\n",
1502                            sha1_to_hex(parent->object.sha1));
1503                free(parents);
1504                parents = next;
1505        }
1506
1507        /* Person/date information */
1508        if (!author)
1509                author = git_author_info(IDENT_STRICT);
1510        strbuf_addf(&buffer, "author %s\n", author);
1511        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1512        if (!encoding_is_utf8)
1513                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1514
1515        while (extra) {
1516                add_extra_header(&buffer, extra);
1517                extra = extra->next;
1518        }
1519        strbuf_addch(&buffer, '\n');
1520
1521        /* And add the comment */
1522        strbuf_addbuf(&buffer, msg);
1523
1524        /* And check the encoding */
1525        if (encoding_is_utf8 && !verify_utf8(&buffer))
1526                fprintf(stderr, commit_utf8_warn);
1527
1528        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1529                return -1;
1530
1531        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1532        strbuf_release(&buffer);
1533        return result;
1534}
1535
1536struct commit *get_merge_parent(const char *name)
1537{
1538        struct object *obj;
1539        struct commit *commit;
1540        unsigned char sha1[20];
1541        if (get_sha1(name, sha1))
1542                return NULL;
1543        obj = parse_object(sha1);
1544        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1545        if (commit && !commit->util) {
1546                struct merge_remote_desc *desc;
1547                desc = xmalloc(sizeof(*desc));
1548                desc->obj = obj;
1549                desc->name = strdup(name);
1550                commit->util = desc;
1551        }
1552        return commit;
1553}
1554
1555/*
1556 * Append a commit to the end of the commit_list.
1557 *
1558 * next starts by pointing to the variable that holds the head of an
1559 * empty commit_list, and is updated to point to the "next" field of
1560 * the last item on the list as new commits are appended.
1561 *
1562 * Usage example:
1563 *
1564 *     struct commit_list *list;
1565 *     struct commit_list **next = &list;
1566 *
1567 *     next = commit_list_append(c1, next);
1568 *     next = commit_list_append(c2, next);
1569 *     assert(commit_list_count(list) == 2);
1570 *     return list;
1571 */
1572struct commit_list **commit_list_append(struct commit *commit,
1573                                        struct commit_list **next)
1574{
1575        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1576        new->item = commit;
1577        *next = new;
1578        new->next = NULL;
1579        return &new->next;
1580}
1581
1582void print_commit_list(struct commit_list *list,
1583                       const char *format_cur,
1584                       const char *format_last)
1585{
1586        for ( ; list; list = list->next) {
1587                const char *format = list->next ? format_cur : format_last;
1588                printf(format, sha1_to_hex(list->item->object.sha1));
1589        }
1590}