Andrew's git / gitweb.git / commit.c
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commit.con commit sequencer: use logmsg_reencode in get_message (d74a4e5)
   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#include "sha1-lookup.h"
  14
  15static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  16
  17int save_commit_buffer = 1;
  18
  19const char *commit_type = "commit";
  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                return create_object(sha1, OBJ_COMMIT, c);
  67        }
  68        if (!obj->type)
  69                obj->type = OBJ_COMMIT;
  70        return check_commit(obj, sha1, 0);
  71}
  72
  73struct commit *lookup_commit_reference_by_name(const char *name)
  74{
  75        unsigned char sha1[20];
  76        struct commit *commit;
  77
  78        if (get_sha1_committish(name, sha1))
  79                return NULL;
  80        commit = lookup_commit_reference(sha1);
  81        if (parse_commit(commit))
  82                return NULL;
  83        return commit;
  84}
  85
  86static unsigned long parse_commit_date(const char *buf, const char *tail)
  87{
  88        const char *dateptr;
  89
  90        if (buf + 6 >= tail)
  91                return 0;
  92        if (memcmp(buf, "author", 6))
  93                return 0;
  94        while (buf < tail && *buf++ != '\n')
  95                /* nada */;
  96        if (buf + 9 >= tail)
  97                return 0;
  98        if (memcmp(buf, "committer", 9))
  99                return 0;
 100        while (buf < tail && *buf++ != '>')
 101                /* nada */;
 102        if (buf >= tail)
 103                return 0;
 104        dateptr = buf;
 105        while (buf < tail && *buf++ != '\n')
 106                /* nada */;
 107        if (buf >= tail)
 108                return 0;
 109        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 110        return strtoul(dateptr, NULL, 10);
 111}
 112
 113static struct commit_graft **commit_graft;
 114static int commit_graft_alloc, commit_graft_nr;
 115
 116static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 117{
 118        struct commit_graft **commit_graft_table = table;
 119        return commit_graft_table[index]->sha1;
 120}
 121
 122static int commit_graft_pos(const unsigned char *sha1)
 123{
 124        return sha1_pos(sha1, commit_graft, commit_graft_nr,
 125                        commit_graft_sha1_access);
 126}
 127
 128int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 129{
 130        int pos = commit_graft_pos(graft->sha1);
 131
 132        if (0 <= pos) {
 133                if (ignore_dups)
 134                        free(graft);
 135                else {
 136                        free(commit_graft[pos]);
 137                        commit_graft[pos] = graft;
 138                }
 139                return 1;
 140        }
 141        pos = -pos - 1;
 142        ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 143        commit_graft_nr++;
 144        if (pos < commit_graft_nr)
 145                memmove(commit_graft + pos + 1,
 146                        commit_graft + pos,
 147                        (commit_graft_nr - pos - 1) *
 148                        sizeof(*commit_graft));
 149        commit_graft[pos] = graft;
 150        return 0;
 151}
 152
 153struct commit_graft *read_graft_line(char *buf, int len)
 154{
 155        /* The format is just "Commit Parent1 Parent2 ...\n" */
 156        int i;
 157        struct commit_graft *graft = NULL;
 158
 159        while (len && isspace(buf[len-1]))
 160                buf[--len] = '\0';
 161        if (buf[0] == '#' || buf[0] == '\0')
 162                return NULL;
 163        if ((len + 1) % 41)
 164                goto bad_graft_data;
 165        i = (len + 1) / 41 - 1;
 166        graft = xmalloc(sizeof(*graft) + 20 * i);
 167        graft->nr_parent = i;
 168        if (get_sha1_hex(buf, graft->sha1))
 169                goto bad_graft_data;
 170        for (i = 40; i < len; i += 41) {
 171                if (buf[i] != ' ')
 172                        goto bad_graft_data;
 173                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 174                        goto bad_graft_data;
 175        }
 176        return graft;
 177
 178bad_graft_data:
 179        error("bad graft data: %s", buf);
 180        free(graft);
 181        return NULL;
 182}
 183
 184static int read_graft_file(const char *graft_file)
 185{
 186        FILE *fp = fopen(graft_file, "r");
 187        struct strbuf buf = STRBUF_INIT;
 188        if (!fp)
 189                return -1;
 190        while (!strbuf_getwholeline(&buf, fp, '\n')) {
 191                /* The format is just "Commit Parent1 Parent2 ...\n" */
 192                struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 193                if (!graft)
 194                        continue;
 195                if (register_commit_graft(graft, 1))
 196                        error("duplicate graft data: %s", buf.buf);
 197        }
 198        fclose(fp);
 199        strbuf_release(&buf);
 200        return 0;
 201}
 202
 203static void prepare_commit_graft(void)
 204{
 205        static int commit_graft_prepared;
 206        char *graft_file;
 207
 208        if (commit_graft_prepared)
 209                return;
 210        graft_file = get_graft_file();
 211        read_graft_file(graft_file);
 212        /* make sure shallows are read */
 213        is_repository_shallow();
 214        commit_graft_prepared = 1;
 215}
 216
 217struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 218{
 219        int pos;
 220        prepare_commit_graft();
 221        pos = commit_graft_pos(sha1);
 222        if (pos < 0)
 223                return NULL;
 224        return commit_graft[pos];
 225}
 226
 227int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 228{
 229        int i, ret;
 230        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 231                ret = fn(commit_graft[i], cb_data);
 232        return ret;
 233}
 234
 235int unregister_shallow(const unsigned char *sha1)
 236{
 237        int pos = commit_graft_pos(sha1);
 238        if (pos < 0)
 239                return -1;
 240        if (pos + 1 < commit_graft_nr)
 241                memmove(commit_graft + pos, commit_graft + pos + 1,
 242                                sizeof(struct commit_graft *)
 243                                * (commit_graft_nr - pos - 1));
 244        commit_graft_nr--;
 245        return 0;
 246}
 247
 248int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 249{
 250        const char *tail = buffer;
 251        const char *bufptr = buffer;
 252        unsigned char parent[20];
 253        struct commit_list **pptr;
 254        struct commit_graft *graft;
 255
 256        if (item->object.parsed)
 257                return 0;
 258        item->object.parsed = 1;
 259        tail += size;
 260        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 261                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 262        if (get_sha1_hex(bufptr + 5, parent) < 0)
 263                return error("bad tree pointer in commit %s",
 264                             sha1_to_hex(item->object.sha1));
 265        item->tree = lookup_tree(parent);
 266        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 267        pptr = &item->parents;
 268
 269        graft = lookup_commit_graft(item->object.sha1);
 270        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 271                struct commit *new_parent;
 272
 273                if (tail <= bufptr + 48 ||
 274                    get_sha1_hex(bufptr + 7, parent) ||
 275                    bufptr[47] != '\n')
 276                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 277                bufptr += 48;
 278                /*
 279                 * The clone is shallow if nr_parent < 0, and we must
 280                 * not traverse its real parents even when we unhide them.
 281                 */
 282                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 283                        continue;
 284                new_parent = lookup_commit(parent);
 285                if (new_parent)
 286                        pptr = &commit_list_insert(new_parent, pptr)->next;
 287        }
 288        if (graft) {
 289                int i;
 290                struct commit *new_parent;
 291                for (i = 0; i < graft->nr_parent; i++) {
 292                        new_parent = lookup_commit(graft->parent[i]);
 293                        if (!new_parent)
 294                                continue;
 295                        pptr = &commit_list_insert(new_parent, pptr)->next;
 296                }
 297        }
 298        item->date = parse_commit_date(bufptr, tail);
 299
 300        return 0;
 301}
 302
 303int parse_commit(struct commit *item)
 304{
 305        enum object_type type;
 306        void *buffer;
 307        unsigned long size;
 308        int ret;
 309
 310        if (!item)
 311                return -1;
 312        if (item->object.parsed)
 313                return 0;
 314        buffer = read_sha1_file(item->object.sha1, &type, &size);
 315        if (!buffer)
 316                return error("Could not read %s",
 317                             sha1_to_hex(item->object.sha1));
 318        if (type != OBJ_COMMIT) {
 319                free(buffer);
 320                return error("Object %s not a commit",
 321                             sha1_to_hex(item->object.sha1));
 322        }
 323        ret = parse_commit_buffer(item, buffer, size);
 324        if (save_commit_buffer && !ret) {
 325                item->buffer = buffer;
 326                return 0;
 327        }
 328        free(buffer);
 329        return ret;
 330}
 331
 332void parse_commit_or_die(struct commit *item)
 333{
 334        if (parse_commit(item))
 335                die("unable to parse commit %s",
 336                    item ? sha1_to_hex(item->object.sha1) : "(null)");
 337}
 338
 339int find_commit_subject(const char *commit_buffer, const char **subject)
 340{
 341        const char *eol;
 342        const char *p = commit_buffer;
 343
 344        while (*p && (*p != '\n' || p[1] != '\n'))
 345                p++;
 346        if (*p) {
 347                p += 2;
 348                for (eol = p; *eol && *eol != '\n'; eol++)
 349                        ; /* do nothing */
 350        } else
 351                eol = p;
 352
 353        *subject = p;
 354
 355        return eol - p;
 356}
 357
 358struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 359{
 360        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 361        new_list->item = item;
 362        new_list->next = *list_p;
 363        *list_p = new_list;
 364        return new_list;
 365}
 366
 367unsigned commit_list_count(const struct commit_list *l)
 368{
 369        unsigned c = 0;
 370        for (; l; l = l->next )
 371                c++;
 372        return c;
 373}
 374
 375struct commit_list *copy_commit_list(struct commit_list *list)
 376{
 377        struct commit_list *head = NULL;
 378        struct commit_list **pp = &head;
 379        while (list) {
 380                struct commit_list *new;
 381                new = xmalloc(sizeof(struct commit_list));
 382                new->item = list->item;
 383                new->next = NULL;
 384                *pp = new;
 385                pp = &new->next;
 386                list = list->next;
 387        }
 388        return head;
 389}
 390
 391void free_commit_list(struct commit_list *list)
 392{
 393        while (list) {
 394                struct commit_list *temp = list;
 395                list = temp->next;
 396                free(temp);
 397        }
 398}
 399
 400struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 401{
 402        struct commit_list **pp = list;
 403        struct commit_list *p;
 404        while ((p = *pp) != NULL) {
 405                if (p->item->date < item->date) {
 406                        break;
 407                }
 408                pp = &p->next;
 409        }
 410        return commit_list_insert(item, pp);
 411}
 412
 413static int commit_list_compare_by_date(const void *a, const void *b)
 414{
 415        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 416        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 417        if (a_date < b_date)
 418                return 1;
 419        if (a_date > b_date)
 420                return -1;
 421        return 0;
 422}
 423
 424static void *commit_list_get_next(const void *a)
 425{
 426        return ((const struct commit_list *)a)->next;
 427}
 428
 429static void commit_list_set_next(void *a, void *next)
 430{
 431        ((struct commit_list *)a)->next = next;
 432}
 433
 434void commit_list_sort_by_date(struct commit_list **list)
 435{
 436        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 437                                commit_list_compare_by_date);
 438}
 439
 440struct commit *pop_most_recent_commit(struct commit_list **list,
 441                                      unsigned int mark)
 442{
 443        struct commit *ret = (*list)->item;
 444        struct commit_list *parents = ret->parents;
 445        struct commit_list *old = *list;
 446
 447        *list = (*list)->next;
 448        free(old);
 449
 450        while (parents) {
 451                struct commit *commit = parents->item;
 452                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 453                        commit->object.flags |= mark;
 454                        commit_list_insert_by_date(commit, list);
 455                }
 456                parents = parents->next;
 457        }
 458        return ret;
 459}
 460
 461static void clear_commit_marks_1(struct commit_list **plist,
 462                                 struct commit *commit, unsigned int mark)
 463{
 464        while (commit) {
 465                struct commit_list *parents;
 466
 467                if (!(mark & commit->object.flags))
 468                        return;
 469
 470                commit->object.flags &= ~mark;
 471
 472                parents = commit->parents;
 473                if (!parents)
 474                        return;
 475
 476                while ((parents = parents->next))
 477                        commit_list_insert(parents->item, plist);
 478
 479                commit = commit->parents->item;
 480        }
 481}
 482
 483void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 484{
 485        struct commit_list *list = NULL;
 486
 487        while (nr--) {
 488                commit_list_insert(*commit, &list);
 489                commit++;
 490        }
 491        while (list)
 492                clear_commit_marks_1(&list, pop_commit(&list), mark);
 493}
 494
 495void clear_commit_marks(struct commit *commit, unsigned int mark)
 496{
 497        clear_commit_marks_many(1, &commit, mark);
 498}
 499
 500void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 501{
 502        struct object *object;
 503        struct commit *commit;
 504        unsigned int i;
 505
 506        for (i = 0; i < a->nr; i++) {
 507                object = a->objects[i].item;
 508                commit = lookup_commit_reference_gently(object->sha1, 1);
 509                if (commit)
 510                        clear_commit_marks(commit, mark);
 511        }
 512}
 513
 514struct commit *pop_commit(struct commit_list **stack)
 515{
 516        struct commit_list *top = *stack;
 517        struct commit *item = top ? top->item : NULL;
 518
 519        if (top) {
 520                *stack = top->next;
 521                free(top);
 522        }
 523        return item;
 524}
 525
 526/*
 527 * Topological sort support
 528 */
 529
 530/* count number of children that have not been emitted */
 531define_commit_slab(indegree_slab, int);
 532
 533/* record author-date for each commit object */
 534define_commit_slab(author_date_slab, unsigned long);
 535
 536static void record_author_date(struct author_date_slab *author_date,
 537                               struct commit *commit)
 538{
 539        const char *buf, *line_end, *ident_line;
 540        char *buffer = NULL;
 541        struct ident_split ident;
 542        char *date_end;
 543        unsigned long date;
 544
 545        if (!commit->buffer) {
 546                unsigned long size;
 547                enum object_type type;
 548                buffer = read_sha1_file(commit->object.sha1, &type, &size);
 549                if (!buffer)
 550                        return;
 551        }
 552
 553        for (buf = commit->buffer ? commit->buffer : buffer;
 554             buf;
 555             buf = line_end + 1) {
 556                line_end = strchrnul(buf, '\n');
 557                ident_line = skip_prefix(buf, "author ");
 558                if (!ident_line) {
 559                        if (!line_end[0] || line_end[1] == '\n')
 560                                return; /* end of header */
 561                        continue;
 562                }
 563                if (split_ident_line(&ident,
 564                                     ident_line, line_end - ident_line) ||
 565                    !ident.date_begin || !ident.date_end)
 566                        goto fail_exit; /* malformed "author" line */
 567                break;
 568        }
 569
 570        date = strtoul(ident.date_begin, &date_end, 10);
 571        if (date_end != ident.date_end)
 572                goto fail_exit; /* malformed date */
 573        *(author_date_slab_at(author_date, commit)) = date;
 574
 575fail_exit:
 576        free(buffer);
 577}
 578
 579static int compare_commits_by_author_date(const void *a_, const void *b_,
 580                                          void *cb_data)
 581{
 582        const struct commit *a = a_, *b = b_;
 583        struct author_date_slab *author_date = cb_data;
 584        unsigned long a_date = *(author_date_slab_at(author_date, a));
 585        unsigned long b_date = *(author_date_slab_at(author_date, b));
 586
 587        /* newer commits with larger date first */
 588        if (a_date < b_date)
 589                return 1;
 590        else if (a_date > b_date)
 591                return -1;
 592        return 0;
 593}
 594
 595int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 596{
 597        const struct commit *a = a_, *b = b_;
 598        /* newer commits with larger date first */
 599        if (a->date < b->date)
 600                return 1;
 601        else if (a->date > b->date)
 602                return -1;
 603        return 0;
 604}
 605
 606/*
 607 * Performs an in-place topological sort on the list supplied.
 608 */
 609void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 610{
 611        struct commit_list *next, *orig = *list;
 612        struct commit_list **pptr;
 613        struct indegree_slab indegree;
 614        struct prio_queue queue;
 615        struct commit *commit;
 616        struct author_date_slab author_date;
 617
 618        if (!orig)
 619                return;
 620        *list = NULL;
 621
 622        init_indegree_slab(&indegree);
 623        memset(&queue, '\0', sizeof(queue));
 624
 625        switch (sort_order) {
 626        default: /* REV_SORT_IN_GRAPH_ORDER */
 627                queue.compare = NULL;
 628                break;
 629        case REV_SORT_BY_COMMIT_DATE:
 630                queue.compare = compare_commits_by_commit_date;
 631                break;
 632        case REV_SORT_BY_AUTHOR_DATE:
 633                init_author_date_slab(&author_date);
 634                queue.compare = compare_commits_by_author_date;
 635                queue.cb_data = &author_date;
 636                break;
 637        }
 638
 639        /* Mark them and clear the indegree */
 640        for (next = orig; next; next = next->next) {
 641                struct commit *commit = next->item;
 642                *(indegree_slab_at(&indegree, commit)) = 1;
 643                /* also record the author dates, if needed */
 644                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 645                        record_author_date(&author_date, commit);
 646        }
 647
 648        /* update the indegree */
 649        for (next = orig; next; next = next->next) {
 650                struct commit_list *parents = next->item->parents;
 651                while (parents) {
 652                        struct commit *parent = parents->item;
 653                        int *pi = indegree_slab_at(&indegree, parent);
 654
 655                        if (*pi)
 656                                (*pi)++;
 657                        parents = parents->next;
 658                }
 659        }
 660
 661        /*
 662         * find the tips
 663         *
 664         * tips are nodes not reachable from any other node in the list
 665         *
 666         * the tips serve as a starting set for the work queue.
 667         */
 668        for (next = orig; next; next = next->next) {
 669                struct commit *commit = next->item;
 670
 671                if (*(indegree_slab_at(&indegree, commit)) == 1)
 672                        prio_queue_put(&queue, commit);
 673        }
 674
 675        /*
 676         * This is unfortunate; the initial tips need to be shown
 677         * in the order given from the revision traversal machinery.
 678         */
 679        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 680                prio_queue_reverse(&queue);
 681
 682        /* We no longer need the commit list */
 683        free_commit_list(orig);
 684
 685        pptr = list;
 686        *list = NULL;
 687        while ((commit = prio_queue_get(&queue)) != NULL) {
 688                struct commit_list *parents;
 689
 690                for (parents = commit->parents; parents ; parents = parents->next) {
 691                        struct commit *parent = parents->item;
 692                        int *pi = indegree_slab_at(&indegree, parent);
 693
 694                        if (!*pi)
 695                                continue;
 696
 697                        /*
 698                         * parents are only enqueued for emission
 699                         * when all their children have been emitted thereby
 700                         * guaranteeing topological order.
 701                         */
 702                        if (--(*pi) == 1)
 703                                prio_queue_put(&queue, parent);
 704                }
 705                /*
 706                 * all children of commit have already been
 707                 * emitted. we can emit it now.
 708                 */
 709                *(indegree_slab_at(&indegree, commit)) = 0;
 710
 711                pptr = &commit_list_insert(commit, pptr)->next;
 712        }
 713
 714        clear_indegree_slab(&indegree);
 715        clear_prio_queue(&queue);
 716        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 717                clear_author_date_slab(&author_date);
 718}
 719
 720/* merge-base stuff */
 721
 722/* Remember to update object flag allocation in object.h */
 723#define PARENT1         (1u<<16)
 724#define PARENT2         (1u<<17)
 725#define STALE           (1u<<18)
 726#define RESULT          (1u<<19)
 727
 728static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 729
 730static struct commit *interesting(struct commit_list *list)
 731{
 732        while (list) {
 733                struct commit *commit = list->item;
 734                list = list->next;
 735                if (commit->object.flags & STALE)
 736                        continue;
 737                return commit;
 738        }
 739        return NULL;
 740}
 741
 742/* all input commits in one and twos[] must have been parsed! */
 743static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 744{
 745        struct commit_list *list = NULL;
 746        struct commit_list *result = NULL;
 747        int i;
 748
 749        one->object.flags |= PARENT1;
 750        commit_list_insert_by_date(one, &list);
 751        if (!n)
 752                return list;
 753        for (i = 0; i < n; i++) {
 754                twos[i]->object.flags |= PARENT2;
 755                commit_list_insert_by_date(twos[i], &list);
 756        }
 757
 758        while (interesting(list)) {
 759                struct commit *commit;
 760                struct commit_list *parents;
 761                struct commit_list *next;
 762                int flags;
 763
 764                commit = list->item;
 765                next = list->next;
 766                free(list);
 767                list = next;
 768
 769                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 770                if (flags == (PARENT1 | PARENT2)) {
 771                        if (!(commit->object.flags & RESULT)) {
 772                                commit->object.flags |= RESULT;
 773                                commit_list_insert_by_date(commit, &result);
 774                        }
 775                        /* Mark parents of a found merge stale */
 776                        flags |= STALE;
 777                }
 778                parents = commit->parents;
 779                while (parents) {
 780                        struct commit *p = parents->item;
 781                        parents = parents->next;
 782                        if ((p->object.flags & flags) == flags)
 783                                continue;
 784                        if (parse_commit(p))
 785                                return NULL;
 786                        p->object.flags |= flags;
 787                        commit_list_insert_by_date(p, &list);
 788                }
 789        }
 790
 791        free_commit_list(list);
 792        return result;
 793}
 794
 795static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 796{
 797        struct commit_list *list = NULL;
 798        struct commit_list *result = NULL;
 799        int i;
 800
 801        for (i = 0; i < n; i++) {
 802                if (one == twos[i])
 803                        /*
 804                         * We do not mark this even with RESULT so we do not
 805                         * have to clean it up.
 806                         */
 807                        return commit_list_insert(one, &result);
 808        }
 809
 810        if (parse_commit(one))
 811                return NULL;
 812        for (i = 0; i < n; i++) {
 813                if (parse_commit(twos[i]))
 814                        return NULL;
 815        }
 816
 817        list = paint_down_to_common(one, n, twos);
 818
 819        while (list) {
 820                struct commit_list *next = list->next;
 821                if (!(list->item->object.flags & STALE))
 822                        commit_list_insert_by_date(list->item, &result);
 823                free(list);
 824                list = next;
 825        }
 826        return result;
 827}
 828
 829struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 830{
 831        struct commit_list *i, *j, *k, *ret = NULL;
 832
 833        if (!in)
 834                return ret;
 835
 836        commit_list_insert(in->item, &ret);
 837
 838        for (i = in->next; i; i = i->next) {
 839                struct commit_list *new = NULL, *end = NULL;
 840
 841                for (j = ret; j; j = j->next) {
 842                        struct commit_list *bases;
 843                        bases = get_merge_bases(i->item, j->item, 1);
 844                        if (!new)
 845                                new = bases;
 846                        else
 847                                end->next = bases;
 848                        for (k = bases; k; k = k->next)
 849                                end = k;
 850                }
 851                ret = new;
 852        }
 853        return ret;
 854}
 855
 856static int remove_redundant(struct commit **array, int cnt)
 857{
 858        /*
 859         * Some commit in the array may be an ancestor of
 860         * another commit.  Move such commit to the end of
 861         * the array, and return the number of commits that
 862         * are independent from each other.
 863         */
 864        struct commit **work;
 865        unsigned char *redundant;
 866        int *filled_index;
 867        int i, j, filled;
 868
 869        work = xcalloc(cnt, sizeof(*work));
 870        redundant = xcalloc(cnt, 1);
 871        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 872
 873        for (i = 0; i < cnt; i++)
 874                parse_commit(array[i]);
 875        for (i = 0; i < cnt; i++) {
 876                struct commit_list *common;
 877
 878                if (redundant[i])
 879                        continue;
 880                for (j = filled = 0; j < cnt; j++) {
 881                        if (i == j || redundant[j])
 882                                continue;
 883                        filled_index[filled] = j;
 884                        work[filled++] = array[j];
 885                }
 886                common = paint_down_to_common(array[i], filled, work);
 887                if (array[i]->object.flags & PARENT2)
 888                        redundant[i] = 1;
 889                for (j = 0; j < filled; j++)
 890                        if (work[j]->object.flags & PARENT1)
 891                                redundant[filled_index[j]] = 1;
 892                clear_commit_marks(array[i], all_flags);
 893                for (j = 0; j < filled; j++)
 894                        clear_commit_marks(work[j], all_flags);
 895                free_commit_list(common);
 896        }
 897
 898        /* Now collect the result */
 899        memcpy(work, array, sizeof(*array) * cnt);
 900        for (i = filled = 0; i < cnt; i++)
 901                if (!redundant[i])
 902                        array[filled++] = work[i];
 903        for (j = filled, i = 0; i < cnt; i++)
 904                if (redundant[i])
 905                        array[j++] = work[i];
 906        free(work);
 907        free(redundant);
 908        free(filled_index);
 909        return filled;
 910}
 911
 912struct commit_list *get_merge_bases_many(struct commit *one,
 913                                         int n,
 914                                         struct commit **twos,
 915                                         int cleanup)
 916{
 917        struct commit_list *list;
 918        struct commit **rslt;
 919        struct commit_list *result;
 920        int cnt, i;
 921
 922        result = merge_bases_many(one, n, twos);
 923        for (i = 0; i < n; i++) {
 924                if (one == twos[i])
 925                        return result;
 926        }
 927        if (!result || !result->next) {
 928                if (cleanup) {
 929                        clear_commit_marks(one, all_flags);
 930                        clear_commit_marks_many(n, twos, all_flags);
 931                }
 932                return result;
 933        }
 934
 935        /* There are more than one */
 936        cnt = 0;
 937        list = result;
 938        while (list) {
 939                list = list->next;
 940                cnt++;
 941        }
 942        rslt = xcalloc(cnt, sizeof(*rslt));
 943        for (list = result, i = 0; list; list = list->next)
 944                rslt[i++] = list->item;
 945        free_commit_list(result);
 946
 947        clear_commit_marks(one, all_flags);
 948        clear_commit_marks_many(n, twos, all_flags);
 949
 950        cnt = remove_redundant(rslt, cnt);
 951        result = NULL;
 952        for (i = 0; i < cnt; i++)
 953                commit_list_insert_by_date(rslt[i], &result);
 954        free(rslt);
 955        return result;
 956}
 957
 958struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 959                                    int cleanup)
 960{
 961        return get_merge_bases_many(one, 1, &two, cleanup);
 962}
 963
 964/*
 965 * Is "commit" a descendant of one of the elements on the "with_commit" list?
 966 */
 967int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 968{
 969        if (!with_commit)
 970                return 1;
 971        while (with_commit) {
 972                struct commit *other;
 973
 974                other = with_commit->item;
 975                with_commit = with_commit->next;
 976                if (in_merge_bases(other, commit))
 977                        return 1;
 978        }
 979        return 0;
 980}
 981
 982/*
 983 * Is "commit" an ancestor of one of the "references"?
 984 */
 985int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 986{
 987        struct commit_list *bases;
 988        int ret = 0, i;
 989
 990        if (parse_commit(commit))
 991                return ret;
 992        for (i = 0; i < nr_reference; i++)
 993                if (parse_commit(reference[i]))
 994                        return ret;
 995
 996        bases = paint_down_to_common(commit, nr_reference, reference);
 997        if (commit->object.flags & PARENT2)
 998                ret = 1;
 999        clear_commit_marks(commit, all_flags);
1000        clear_commit_marks_many(nr_reference, reference, all_flags);
1001        free_commit_list(bases);
1002        return ret;
1003}
1004
1005/*
1006 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1007 */
1008int in_merge_bases(struct commit *commit, struct commit *reference)
1009{
1010        return in_merge_bases_many(commit, 1, &reference);
1011}
1012
1013struct commit_list *reduce_heads(struct commit_list *heads)
1014{
1015        struct commit_list *p;
1016        struct commit_list *result = NULL, **tail = &result;
1017        struct commit **array;
1018        int num_head, i;
1019
1020        if (!heads)
1021                return NULL;
1022
1023        /* Uniquify */
1024        for (p = heads; p; p = p->next)
1025                p->item->object.flags &= ~STALE;
1026        for (p = heads, num_head = 0; p; p = p->next) {
1027                if (p->item->object.flags & STALE)
1028                        continue;
1029                p->item->object.flags |= STALE;
1030                num_head++;
1031        }
1032        array = xcalloc(sizeof(*array), num_head);
1033        for (p = heads, i = 0; p; p = p->next) {
1034                if (p->item->object.flags & STALE) {
1035                        array[i++] = p->item;
1036                        p->item->object.flags &= ~STALE;
1037                }
1038        }
1039        num_head = remove_redundant(array, num_head);
1040        for (i = 0; i < num_head; i++)
1041                tail = &commit_list_insert(array[i], tail)->next;
1042        return result;
1043}
1044
1045static const char gpg_sig_header[] = "gpgsig";
1046static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1047
1048static int do_sign_commit(struct strbuf *buf, const char *keyid)
1049{
1050        struct strbuf sig = STRBUF_INIT;
1051        int inspos, copypos;
1052
1053        /* find the end of the header */
1054        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1055
1056        if (!keyid || !*keyid)
1057                keyid = get_signing_key();
1058        if (sign_buffer(buf, &sig, keyid)) {
1059                strbuf_release(&sig);
1060                return -1;
1061        }
1062
1063        for (copypos = 0; sig.buf[copypos]; ) {
1064                const char *bol = sig.buf + copypos;
1065                const char *eol = strchrnul(bol, '\n');
1066                int len = (eol - bol) + !!*eol;
1067
1068                if (!copypos) {
1069                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1070                        inspos += gpg_sig_header_len;
1071                }
1072                strbuf_insert(buf, inspos++, " ", 1);
1073                strbuf_insert(buf, inspos, bol, len);
1074                inspos += len;
1075                copypos += len;
1076        }
1077        strbuf_release(&sig);
1078        return 0;
1079}
1080
1081int parse_signed_commit(const unsigned char *sha1,
1082                        struct strbuf *payload, struct strbuf *signature)
1083{
1084        unsigned long size;
1085        enum object_type type;
1086        char *buffer = read_sha1_file(sha1, &type, &size);
1087        int in_signature, saw_signature = -1;
1088        char *line, *tail;
1089
1090        if (!buffer || type != OBJ_COMMIT)
1091                goto cleanup;
1092
1093        line = buffer;
1094        tail = buffer + size;
1095        in_signature = 0;
1096        saw_signature = 0;
1097        while (line < tail) {
1098                const char *sig = NULL;
1099                char *next = memchr(line, '\n', tail - line);
1100
1101                next = next ? next + 1 : tail;
1102                if (in_signature && line[0] == ' ')
1103                        sig = line + 1;
1104                else if (starts_with(line, gpg_sig_header) &&
1105                         line[gpg_sig_header_len] == ' ')
1106                        sig = line + gpg_sig_header_len + 1;
1107                if (sig) {
1108                        strbuf_add(signature, sig, next - sig);
1109                        saw_signature = 1;
1110                        in_signature = 1;
1111                } else {
1112                        if (*line == '\n')
1113                                /* dump the whole remainder of the buffer */
1114                                next = tail;
1115                        strbuf_add(payload, line, next - line);
1116                        in_signature = 0;
1117                }
1118                line = next;
1119        }
1120 cleanup:
1121        free(buffer);
1122        return saw_signature;
1123}
1124
1125static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1126{
1127        struct merge_remote_desc *desc;
1128        struct commit_extra_header *mergetag;
1129        char *buf;
1130        unsigned long size, len;
1131        enum object_type type;
1132
1133        desc = merge_remote_util(parent);
1134        if (!desc || !desc->obj)
1135                return;
1136        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1137        if (!buf || type != OBJ_TAG)
1138                goto free_return;
1139        len = parse_signature(buf, size);
1140        if (size == len)
1141                goto free_return;
1142        /*
1143         * We could verify this signature and either omit the tag when
1144         * it does not validate, but the integrator may not have the
1145         * public key of the signer of the tag he is merging, while a
1146         * later auditor may have it while auditing, so let's not run
1147         * verify-signed-buffer here for now...
1148         *
1149         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1150         *      warn("warning: signed tag unverified.");
1151         */
1152        mergetag = xcalloc(1, sizeof(*mergetag));
1153        mergetag->key = xstrdup("mergetag");
1154        mergetag->value = buf;
1155        mergetag->len = size;
1156
1157        **tail = mergetag;
1158        *tail = &mergetag->next;
1159        return;
1160
1161free_return:
1162        free(buf);
1163}
1164
1165static struct {
1166        char result;
1167        const char *check;
1168} sigcheck_gpg_status[] = {
1169        { 'G', "\n[GNUPG:] GOODSIG " },
1170        { 'B', "\n[GNUPG:] BADSIG " },
1171        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1172        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1173};
1174
1175static void parse_gpg_output(struct signature_check *sigc)
1176{
1177        const char *buf = sigc->gpg_status;
1178        int i;
1179
1180        /* Iterate over all search strings */
1181        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1182                const char *found, *next;
1183
1184                found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
1185                if (!found) {
1186                        found = strstr(buf, sigcheck_gpg_status[i].check);
1187                        if (!found)
1188                                continue;
1189                        found += strlen(sigcheck_gpg_status[i].check);
1190                }
1191                sigc->result = sigcheck_gpg_status[i].result;
1192                /* The trust messages are not followed by key/signer information */
1193                if (sigc->result != 'U') {
1194                        sigc->key = xmemdupz(found, 16);
1195                        found += 17;
1196                        next = strchrnul(found, '\n');
1197                        sigc->signer = xmemdupz(found, next - found);
1198                }
1199        }
1200}
1201
1202void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1203{
1204        struct strbuf payload = STRBUF_INIT;
1205        struct strbuf signature = STRBUF_INIT;
1206        struct strbuf gpg_output = STRBUF_INIT;
1207        struct strbuf gpg_status = STRBUF_INIT;
1208        int status;
1209
1210        sigc->result = 'N';
1211
1212        if (parse_signed_commit(commit->object.sha1,
1213                                &payload, &signature) <= 0)
1214                goto out;
1215        status = verify_signed_buffer(payload.buf, payload.len,
1216                                      signature.buf, signature.len,
1217                                      &gpg_output, &gpg_status);
1218        if (status && !gpg_output.len)
1219                goto out;
1220        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1221        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1222        parse_gpg_output(sigc);
1223
1224 out:
1225        strbuf_release(&gpg_status);
1226        strbuf_release(&gpg_output);
1227        strbuf_release(&payload);
1228        strbuf_release(&signature);
1229}
1230
1231
1232
1233void append_merge_tag_headers(struct commit_list *parents,
1234                              struct commit_extra_header ***tail)
1235{
1236        while (parents) {
1237                struct commit *parent = parents->item;
1238                handle_signed_tag(parent, tail);
1239                parents = parents->next;
1240        }
1241}
1242
1243static void add_extra_header(struct strbuf *buffer,
1244                             struct commit_extra_header *extra)
1245{
1246        strbuf_addstr(buffer, extra->key);
1247        if (extra->len)
1248                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1249        else
1250                strbuf_addch(buffer, '\n');
1251}
1252
1253struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1254                                                      const char **exclude)
1255{
1256        struct commit_extra_header *extra = NULL;
1257        unsigned long size;
1258        enum object_type type;
1259        char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1260        if (buffer && type == OBJ_COMMIT)
1261                extra = read_commit_extra_header_lines(buffer, size, exclude);
1262        free(buffer);
1263        return extra;
1264}
1265
1266static inline int standard_header_field(const char *field, size_t len)
1267{
1268        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1269                (len == 6 && !memcmp(field, "parent ", 7)) ||
1270                (len == 6 && !memcmp(field, "author ", 7)) ||
1271                (len == 9 && !memcmp(field, "committer ", 10)) ||
1272                (len == 8 && !memcmp(field, "encoding ", 9)));
1273}
1274
1275static int excluded_header_field(const char *field, size_t len, const char **exclude)
1276{
1277        if (!exclude)
1278                return 0;
1279
1280        while (*exclude) {
1281                size_t xlen = strlen(*exclude);
1282                if (len == xlen &&
1283                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1284                        return 1;
1285                exclude++;
1286        }
1287        return 0;
1288}
1289
1290static struct commit_extra_header *read_commit_extra_header_lines(
1291        const char *buffer, size_t size,
1292        const char **exclude)
1293{
1294        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1295        const char *line, *next, *eof, *eob;
1296        struct strbuf buf = STRBUF_INIT;
1297
1298        for (line = buffer, eob = line + size;
1299             line < eob && *line != '\n';
1300             line = next) {
1301                next = memchr(line, '\n', eob - line);
1302                next = next ? next + 1 : eob;
1303                if (*line == ' ') {
1304                        /* continuation */
1305                        if (it)
1306                                strbuf_add(&buf, line + 1, next - (line + 1));
1307                        continue;
1308                }
1309                if (it)
1310                        it->value = strbuf_detach(&buf, &it->len);
1311                strbuf_reset(&buf);
1312                it = NULL;
1313
1314                eof = strchr(line, ' ');
1315                if (next <= eof)
1316                        eof = next;
1317
1318                if (standard_header_field(line, eof - line) ||
1319                    excluded_header_field(line, eof - line, exclude))
1320                        continue;
1321
1322                it = xcalloc(1, sizeof(*it));
1323                it->key = xmemdupz(line, eof-line);
1324                *tail = it;
1325                tail = &it->next;
1326                if (eof + 1 < next)
1327                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1328        }
1329        if (it)
1330                it->value = strbuf_detach(&buf, &it->len);
1331        return extra;
1332}
1333
1334void free_commit_extra_headers(struct commit_extra_header *extra)
1335{
1336        while (extra) {
1337                struct commit_extra_header *next = extra->next;
1338                free(extra->key);
1339                free(extra->value);
1340                free(extra);
1341                extra = next;
1342        }
1343}
1344
1345int commit_tree(const char *msg, size_t msg_len,
1346                const unsigned char *tree,
1347                struct commit_list *parents, unsigned char *ret,
1348                const char *author, const char *sign_commit)
1349{
1350        struct commit_extra_header *extra = NULL, **tail = &extra;
1351        int result;
1352
1353        append_merge_tag_headers(parents, &tail);
1354        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1355                                      author, sign_commit, extra);
1356        free_commit_extra_headers(extra);
1357        return result;
1358}
1359
1360static int find_invalid_utf8(const char *buf, int len)
1361{
1362        int offset = 0;
1363        static const unsigned int max_codepoint[] = {
1364                0x7f, 0x7ff, 0xffff, 0x10ffff
1365        };
1366
1367        while (len) {
1368                unsigned char c = *buf++;
1369                int bytes, bad_offset;
1370                unsigned int codepoint;
1371                unsigned int min_val, max_val;
1372
1373                len--;
1374                offset++;
1375
1376                /* Simple US-ASCII? No worries. */
1377                if (c < 0x80)
1378                        continue;
1379
1380                bad_offset = offset-1;
1381
1382                /*
1383                 * Count how many more high bits set: that's how
1384                 * many more bytes this sequence should have.
1385                 */
1386                bytes = 0;
1387                while (c & 0x40) {
1388                        c <<= 1;
1389                        bytes++;
1390                }
1391
1392                /*
1393                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1394                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1395                 */
1396                if (bytes < 1 || 3 < bytes)
1397                        return bad_offset;
1398
1399                /* Do we *have* that many bytes? */
1400                if (len < bytes)
1401                        return bad_offset;
1402
1403                /*
1404                 * Place the encoded bits at the bottom of the value and compute the
1405                 * valid range.
1406                 */
1407                codepoint = (c & 0x7f) >> bytes;
1408                min_val = max_codepoint[bytes-1] + 1;
1409                max_val = max_codepoint[bytes];
1410
1411                offset += bytes;
1412                len -= bytes;
1413
1414                /* And verify that they are good continuation bytes */
1415                do {
1416                        codepoint <<= 6;
1417                        codepoint |= *buf & 0x3f;
1418                        if ((*buf++ & 0xc0) != 0x80)
1419                                return bad_offset;
1420                } while (--bytes);
1421
1422                /* Reject codepoints that are out of range for the sequence length. */
1423                if (codepoint < min_val || codepoint > max_val)
1424                        return bad_offset;
1425                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1426                if ((codepoint & 0x1ff800) == 0xd800)
1427                        return bad_offset;
1428                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1429                if ((codepoint & 0xfffe) == 0xfffe)
1430                        return bad_offset;
1431                /* So are anything in the range U+FDD0..U+FDEF. */
1432                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1433                        return bad_offset;
1434        }
1435        return -1;
1436}
1437
1438/*
1439 * This verifies that the buffer is in proper utf8 format.
1440 *
1441 * If it isn't, it assumes any non-utf8 characters are Latin1,
1442 * and does the conversion.
1443 */
1444static int verify_utf8(struct strbuf *buf)
1445{
1446        int ok = 1;
1447        long pos = 0;
1448
1449        for (;;) {
1450                int bad;
1451                unsigned char c;
1452                unsigned char replace[2];
1453
1454                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1455                if (bad < 0)
1456                        return ok;
1457                pos += bad;
1458                ok = 0;
1459                c = buf->buf[pos];
1460                strbuf_remove(buf, pos, 1);
1461
1462                /* We know 'c' must be in the range 128-255 */
1463                replace[0] = 0xc0 + (c >> 6);
1464                replace[1] = 0x80 + (c & 0x3f);
1465                strbuf_insert(buf, pos, replace, 2);
1466                pos += 2;
1467        }
1468}
1469
1470static const char commit_utf8_warn[] =
1471"Warning: commit message did not conform to UTF-8.\n"
1472"You may want to amend it after fixing the message, or set the config\n"
1473"variable i18n.commitencoding to the encoding your project uses.\n";
1474
1475int commit_tree_extended(const char *msg, size_t msg_len,
1476                         const unsigned char *tree,
1477                         struct commit_list *parents, unsigned char *ret,
1478                         const char *author, const char *sign_commit,
1479                         struct commit_extra_header *extra)
1480{
1481        int result;
1482        int encoding_is_utf8;
1483        struct strbuf buffer;
1484
1485        assert_sha1_type(tree, OBJ_TREE);
1486
1487        if (memchr(msg, '\0', msg_len))
1488                return error("a NUL byte in commit log message not allowed.");
1489
1490        /* Not having i18n.commitencoding is the same as having utf-8 */
1491        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1492
1493        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1494        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1495
1496        /*
1497         * NOTE! This ordering means that the same exact tree merged with a
1498         * different order of parents will be a _different_ changeset even
1499         * if everything else stays the same.
1500         */
1501        while (parents) {
1502                struct commit_list *next = parents->next;
1503                struct commit *parent = parents->item;
1504
1505                strbuf_addf(&buffer, "parent %s\n",
1506                            sha1_to_hex(parent->object.sha1));
1507                free(parents);
1508                parents = next;
1509        }
1510
1511        /* Person/date information */
1512        if (!author)
1513                author = git_author_info(IDENT_STRICT);
1514        strbuf_addf(&buffer, "author %s\n", author);
1515        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1516        if (!encoding_is_utf8)
1517                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1518
1519        while (extra) {
1520                add_extra_header(&buffer, extra);
1521                extra = extra->next;
1522        }
1523        strbuf_addch(&buffer, '\n');
1524
1525        /* And add the comment */
1526        strbuf_add(&buffer, msg, msg_len);
1527
1528        /* And check the encoding */
1529        if (encoding_is_utf8 && !verify_utf8(&buffer))
1530                fprintf(stderr, commit_utf8_warn);
1531
1532        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1533                return -1;
1534
1535        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1536        strbuf_release(&buffer);
1537        return result;
1538}
1539
1540struct commit *get_merge_parent(const char *name)
1541{
1542        struct object *obj;
1543        struct commit *commit;
1544        unsigned char sha1[20];
1545        if (get_sha1(name, sha1))
1546                return NULL;
1547        obj = parse_object(sha1);
1548        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1549        if (commit && !commit->util) {
1550                struct merge_remote_desc *desc;
1551                desc = xmalloc(sizeof(*desc));
1552                desc->obj = obj;
1553                desc->name = strdup(name);
1554                commit->util = desc;
1555        }
1556        return commit;
1557}
1558
1559/*
1560 * Append a commit to the end of the commit_list.
1561 *
1562 * next starts by pointing to the variable that holds the head of an
1563 * empty commit_list, and is updated to point to the "next" field of
1564 * the last item on the list as new commits are appended.
1565 *
1566 * Usage example:
1567 *
1568 *     struct commit_list *list;
1569 *     struct commit_list **next = &list;
1570 *
1571 *     next = commit_list_append(c1, next);
1572 *     next = commit_list_append(c2, next);
1573 *     assert(commit_list_count(list) == 2);
1574 *     return list;
1575 */
1576struct commit_list **commit_list_append(struct commit *commit,
1577                                        struct commit_list **next)
1578{
1579        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1580        new->item = commit;
1581        *next = new;
1582        new->next = NULL;
1583        return &new->next;
1584}
1585
1586void print_commit_list(struct commit_list *list,
1587                       const char *format_cur,
1588                       const char *format_last)
1589{
1590        for ( ; list; list = list->next) {
1591                const char *format = list->next ? format_cur : format_last;
1592                printf(format, sha1_to_hex(list->item->object.sha1));
1593        }
1594}