Andrew's git / gitweb.git / commit.c
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commit.con commit use commit_list_count() to count the members of commit_lists (4bbaa1e)
   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
 248struct commit_buffer {
 249        void *buffer;
 250        unsigned long size;
 251};
 252define_commit_slab(buffer_slab, struct commit_buffer);
 253static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 254
 255void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
 256{
 257        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 258        v->buffer = buffer;
 259        v->size = size;
 260}
 261
 262const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
 263{
 264        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 265        if (sizep)
 266                *sizep = v->size;
 267        return v->buffer;
 268}
 269
 270const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 271{
 272        const void *ret = get_cached_commit_buffer(commit, sizep);
 273        if (!ret) {
 274                enum object_type type;
 275                unsigned long size;
 276                ret = read_sha1_file(commit->object.sha1, &type, &size);
 277                if (!ret)
 278                        die("cannot read commit object %s",
 279                            sha1_to_hex(commit->object.sha1));
 280                if (type != OBJ_COMMIT)
 281                        die("expected commit for %s, got %s",
 282                            sha1_to_hex(commit->object.sha1), typename(type));
 283                if (sizep)
 284                        *sizep = size;
 285        }
 286        return ret;
 287}
 288
 289void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 290{
 291        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 292        if (v->buffer != buffer)
 293                free((void *)buffer);
 294}
 295
 296void free_commit_buffer(struct commit *commit)
 297{
 298        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 299        free(v->buffer);
 300        v->buffer = NULL;
 301        v->size = 0;
 302}
 303
 304const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 305{
 306        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 307        void *ret;
 308
 309        ret = v->buffer;
 310        if (sizep)
 311                *sizep = v->size;
 312
 313        v->buffer = NULL;
 314        v->size = 0;
 315        return ret;
 316}
 317
 318int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 319{
 320        const char *tail = buffer;
 321        const char *bufptr = buffer;
 322        unsigned char parent[20];
 323        struct commit_list **pptr;
 324        struct commit_graft *graft;
 325
 326        if (item->object.parsed)
 327                return 0;
 328        item->object.parsed = 1;
 329        tail += size;
 330        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 331                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 332        if (get_sha1_hex(bufptr + 5, parent) < 0)
 333                return error("bad tree pointer in commit %s",
 334                             sha1_to_hex(item->object.sha1));
 335        item->tree = lookup_tree(parent);
 336        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 337        pptr = &item->parents;
 338
 339        graft = lookup_commit_graft(item->object.sha1);
 340        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 341                struct commit *new_parent;
 342
 343                if (tail <= bufptr + 48 ||
 344                    get_sha1_hex(bufptr + 7, parent) ||
 345                    bufptr[47] != '\n')
 346                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 347                bufptr += 48;
 348                /*
 349                 * The clone is shallow if nr_parent < 0, and we must
 350                 * not traverse its real parents even when we unhide them.
 351                 */
 352                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 353                        continue;
 354                new_parent = lookup_commit(parent);
 355                if (new_parent)
 356                        pptr = &commit_list_insert(new_parent, pptr)->next;
 357        }
 358        if (graft) {
 359                int i;
 360                struct commit *new_parent;
 361                for (i = 0; i < graft->nr_parent; i++) {
 362                        new_parent = lookup_commit(graft->parent[i]);
 363                        if (!new_parent)
 364                                continue;
 365                        pptr = &commit_list_insert(new_parent, pptr)->next;
 366                }
 367        }
 368        item->date = parse_commit_date(bufptr, tail);
 369
 370        return 0;
 371}
 372
 373int parse_commit(struct commit *item)
 374{
 375        enum object_type type;
 376        void *buffer;
 377        unsigned long size;
 378        int ret;
 379
 380        if (!item)
 381                return -1;
 382        if (item->object.parsed)
 383                return 0;
 384        buffer = read_sha1_file(item->object.sha1, &type, &size);
 385        if (!buffer)
 386                return error("Could not read %s",
 387                             sha1_to_hex(item->object.sha1));
 388        if (type != OBJ_COMMIT) {
 389                free(buffer);
 390                return error("Object %s not a commit",
 391                             sha1_to_hex(item->object.sha1));
 392        }
 393        ret = parse_commit_buffer(item, buffer, size);
 394        if (save_commit_buffer && !ret) {
 395                set_commit_buffer(item, buffer, size);
 396                return 0;
 397        }
 398        free(buffer);
 399        return ret;
 400}
 401
 402void parse_commit_or_die(struct commit *item)
 403{
 404        if (parse_commit(item))
 405                die("unable to parse commit %s",
 406                    item ? sha1_to_hex(item->object.sha1) : "(null)");
 407}
 408
 409int find_commit_subject(const char *commit_buffer, const char **subject)
 410{
 411        const char *eol;
 412        const char *p = commit_buffer;
 413
 414        while (*p && (*p != '\n' || p[1] != '\n'))
 415                p++;
 416        if (*p) {
 417                p += 2;
 418                for (eol = p; *eol && *eol != '\n'; eol++)
 419                        ; /* do nothing */
 420        } else
 421                eol = p;
 422
 423        *subject = p;
 424
 425        return eol - p;
 426}
 427
 428struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 429{
 430        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 431        new_list->item = item;
 432        new_list->next = *list_p;
 433        *list_p = new_list;
 434        return new_list;
 435}
 436
 437unsigned commit_list_count(const struct commit_list *l)
 438{
 439        unsigned c = 0;
 440        for (; l; l = l->next )
 441                c++;
 442        return c;
 443}
 444
 445struct commit_list *copy_commit_list(struct commit_list *list)
 446{
 447        struct commit_list *head = NULL;
 448        struct commit_list **pp = &head;
 449        while (list) {
 450                pp = commit_list_append(list->item, pp);
 451                list = list->next;
 452        }
 453        return head;
 454}
 455
 456void free_commit_list(struct commit_list *list)
 457{
 458        while (list) {
 459                struct commit_list *temp = list;
 460                list = temp->next;
 461                free(temp);
 462        }
 463}
 464
 465struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 466{
 467        struct commit_list **pp = list;
 468        struct commit_list *p;
 469        while ((p = *pp) != NULL) {
 470                if (p->item->date < item->date) {
 471                        break;
 472                }
 473                pp = &p->next;
 474        }
 475        return commit_list_insert(item, pp);
 476}
 477
 478static int commit_list_compare_by_date(const void *a, const void *b)
 479{
 480        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 481        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 482        if (a_date < b_date)
 483                return 1;
 484        if (a_date > b_date)
 485                return -1;
 486        return 0;
 487}
 488
 489static void *commit_list_get_next(const void *a)
 490{
 491        return ((const struct commit_list *)a)->next;
 492}
 493
 494static void commit_list_set_next(void *a, void *next)
 495{
 496        ((struct commit_list *)a)->next = next;
 497}
 498
 499void commit_list_sort_by_date(struct commit_list **list)
 500{
 501        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 502                                commit_list_compare_by_date);
 503}
 504
 505struct commit *pop_most_recent_commit(struct commit_list **list,
 506                                      unsigned int mark)
 507{
 508        struct commit *ret = (*list)->item;
 509        struct commit_list *parents = ret->parents;
 510        struct commit_list *old = *list;
 511
 512        *list = (*list)->next;
 513        free(old);
 514
 515        while (parents) {
 516                struct commit *commit = parents->item;
 517                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 518                        commit->object.flags |= mark;
 519                        commit_list_insert_by_date(commit, list);
 520                }
 521                parents = parents->next;
 522        }
 523        return ret;
 524}
 525
 526static void clear_commit_marks_1(struct commit_list **plist,
 527                                 struct commit *commit, unsigned int mark)
 528{
 529        while (commit) {
 530                struct commit_list *parents;
 531
 532                if (!(mark & commit->object.flags))
 533                        return;
 534
 535                commit->object.flags &= ~mark;
 536
 537                parents = commit->parents;
 538                if (!parents)
 539                        return;
 540
 541                while ((parents = parents->next))
 542                        commit_list_insert(parents->item, plist);
 543
 544                commit = commit->parents->item;
 545        }
 546}
 547
 548void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 549{
 550        struct commit_list *list = NULL;
 551
 552        while (nr--) {
 553                commit_list_insert(*commit, &list);
 554                commit++;
 555        }
 556        while (list)
 557                clear_commit_marks_1(&list, pop_commit(&list), mark);
 558}
 559
 560void clear_commit_marks(struct commit *commit, unsigned int mark)
 561{
 562        clear_commit_marks_many(1, &commit, mark);
 563}
 564
 565void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 566{
 567        struct object *object;
 568        struct commit *commit;
 569        unsigned int i;
 570
 571        for (i = 0; i < a->nr; i++) {
 572                object = a->objects[i].item;
 573                commit = lookup_commit_reference_gently(object->sha1, 1);
 574                if (commit)
 575                        clear_commit_marks(commit, mark);
 576        }
 577}
 578
 579struct commit *pop_commit(struct commit_list **stack)
 580{
 581        struct commit_list *top = *stack;
 582        struct commit *item = top ? top->item : NULL;
 583
 584        if (top) {
 585                *stack = top->next;
 586                free(top);
 587        }
 588        return item;
 589}
 590
 591/*
 592 * Topological sort support
 593 */
 594
 595/* count number of children that have not been emitted */
 596define_commit_slab(indegree_slab, int);
 597
 598/* record author-date for each commit object */
 599define_commit_slab(author_date_slab, unsigned long);
 600
 601static void record_author_date(struct author_date_slab *author_date,
 602                               struct commit *commit)
 603{
 604        const char *buf, *line_end, *ident_line;
 605        const char *buffer = get_commit_buffer(commit, NULL);
 606        struct ident_split ident;
 607        char *date_end;
 608        unsigned long date;
 609
 610        for (buf = buffer; buf; buf = line_end + 1) {
 611                line_end = strchrnul(buf, '\n');
 612                if (!skip_prefix(buf, "author ", &ident_line)) {
 613                        if (!line_end[0] || line_end[1] == '\n')
 614                                return; /* end of header */
 615                        continue;
 616                }
 617                if (split_ident_line(&ident,
 618                                     ident_line, line_end - ident_line) ||
 619                    !ident.date_begin || !ident.date_end)
 620                        goto fail_exit; /* malformed "author" line */
 621                break;
 622        }
 623
 624        date = strtoul(ident.date_begin, &date_end, 10);
 625        if (date_end != ident.date_end)
 626                goto fail_exit; /* malformed date */
 627        *(author_date_slab_at(author_date, commit)) = date;
 628
 629fail_exit:
 630        unuse_commit_buffer(commit, buffer);
 631}
 632
 633static int compare_commits_by_author_date(const void *a_, const void *b_,
 634                                          void *cb_data)
 635{
 636        const struct commit *a = a_, *b = b_;
 637        struct author_date_slab *author_date = cb_data;
 638        unsigned long a_date = *(author_date_slab_at(author_date, a));
 639        unsigned long b_date = *(author_date_slab_at(author_date, b));
 640
 641        /* newer commits with larger date first */
 642        if (a_date < b_date)
 643                return 1;
 644        else if (a_date > b_date)
 645                return -1;
 646        return 0;
 647}
 648
 649int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 650{
 651        const struct commit *a = a_, *b = b_;
 652        /* newer commits with larger date first */
 653        if (a->date < b->date)
 654                return 1;
 655        else if (a->date > b->date)
 656                return -1;
 657        return 0;
 658}
 659
 660/*
 661 * Performs an in-place topological sort on the list supplied.
 662 */
 663void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 664{
 665        struct commit_list *next, *orig = *list;
 666        struct commit_list **pptr;
 667        struct indegree_slab indegree;
 668        struct prio_queue queue;
 669        struct commit *commit;
 670        struct author_date_slab author_date;
 671
 672        if (!orig)
 673                return;
 674        *list = NULL;
 675
 676        init_indegree_slab(&indegree);
 677        memset(&queue, '\0', sizeof(queue));
 678
 679        switch (sort_order) {
 680        default: /* REV_SORT_IN_GRAPH_ORDER */
 681                queue.compare = NULL;
 682                break;
 683        case REV_SORT_BY_COMMIT_DATE:
 684                queue.compare = compare_commits_by_commit_date;
 685                break;
 686        case REV_SORT_BY_AUTHOR_DATE:
 687                init_author_date_slab(&author_date);
 688                queue.compare = compare_commits_by_author_date;
 689                queue.cb_data = &author_date;
 690                break;
 691        }
 692
 693        /* Mark them and clear the indegree */
 694        for (next = orig; next; next = next->next) {
 695                struct commit *commit = next->item;
 696                *(indegree_slab_at(&indegree, commit)) = 1;
 697                /* also record the author dates, if needed */
 698                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 699                        record_author_date(&author_date, commit);
 700        }
 701
 702        /* update the indegree */
 703        for (next = orig; next; next = next->next) {
 704                struct commit_list *parents = next->item->parents;
 705                while (parents) {
 706                        struct commit *parent = parents->item;
 707                        int *pi = indegree_slab_at(&indegree, parent);
 708
 709                        if (*pi)
 710                                (*pi)++;
 711                        parents = parents->next;
 712                }
 713        }
 714
 715        /*
 716         * find the tips
 717         *
 718         * tips are nodes not reachable from any other node in the list
 719         *
 720         * the tips serve as a starting set for the work queue.
 721         */
 722        for (next = orig; next; next = next->next) {
 723                struct commit *commit = next->item;
 724
 725                if (*(indegree_slab_at(&indegree, commit)) == 1)
 726                        prio_queue_put(&queue, commit);
 727        }
 728
 729        /*
 730         * This is unfortunate; the initial tips need to be shown
 731         * in the order given from the revision traversal machinery.
 732         */
 733        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 734                prio_queue_reverse(&queue);
 735
 736        /* We no longer need the commit list */
 737        free_commit_list(orig);
 738
 739        pptr = list;
 740        *list = NULL;
 741        while ((commit = prio_queue_get(&queue)) != NULL) {
 742                struct commit_list *parents;
 743
 744                for (parents = commit->parents; parents ; parents = parents->next) {
 745                        struct commit *parent = parents->item;
 746                        int *pi = indegree_slab_at(&indegree, parent);
 747
 748                        if (!*pi)
 749                                continue;
 750
 751                        /*
 752                         * parents are only enqueued for emission
 753                         * when all their children have been emitted thereby
 754                         * guaranteeing topological order.
 755                         */
 756                        if (--(*pi) == 1)
 757                                prio_queue_put(&queue, parent);
 758                }
 759                /*
 760                 * all children of commit have already been
 761                 * emitted. we can emit it now.
 762                 */
 763                *(indegree_slab_at(&indegree, commit)) = 0;
 764
 765                pptr = &commit_list_insert(commit, pptr)->next;
 766        }
 767
 768        clear_indegree_slab(&indegree);
 769        clear_prio_queue(&queue);
 770        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 771                clear_author_date_slab(&author_date);
 772}
 773
 774/* merge-base stuff */
 775
 776/* Remember to update object flag allocation in object.h */
 777#define PARENT1         (1u<<16)
 778#define PARENT2         (1u<<17)
 779#define STALE           (1u<<18)
 780#define RESULT          (1u<<19)
 781
 782static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 783
 784static struct commit *interesting(struct commit_list *list)
 785{
 786        while (list) {
 787                struct commit *commit = list->item;
 788                list = list->next;
 789                if (commit->object.flags & STALE)
 790                        continue;
 791                return commit;
 792        }
 793        return NULL;
 794}
 795
 796/* all input commits in one and twos[] must have been parsed! */
 797static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 798{
 799        struct commit_list *list = NULL;
 800        struct commit_list *result = NULL;
 801        int i;
 802
 803        one->object.flags |= PARENT1;
 804        commit_list_insert_by_date(one, &list);
 805        if (!n)
 806                return list;
 807        for (i = 0; i < n; i++) {
 808                twos[i]->object.flags |= PARENT2;
 809                commit_list_insert_by_date(twos[i], &list);
 810        }
 811
 812        while (interesting(list)) {
 813                struct commit *commit;
 814                struct commit_list *parents;
 815                struct commit_list *next;
 816                int flags;
 817
 818                commit = list->item;
 819                next = list->next;
 820                free(list);
 821                list = next;
 822
 823                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 824                if (flags == (PARENT1 | PARENT2)) {
 825                        if (!(commit->object.flags & RESULT)) {
 826                                commit->object.flags |= RESULT;
 827                                commit_list_insert_by_date(commit, &result);
 828                        }
 829                        /* Mark parents of a found merge stale */
 830                        flags |= STALE;
 831                }
 832                parents = commit->parents;
 833                while (parents) {
 834                        struct commit *p = parents->item;
 835                        parents = parents->next;
 836                        if ((p->object.flags & flags) == flags)
 837                                continue;
 838                        if (parse_commit(p))
 839                                return NULL;
 840                        p->object.flags |= flags;
 841                        commit_list_insert_by_date(p, &list);
 842                }
 843        }
 844
 845        free_commit_list(list);
 846        return result;
 847}
 848
 849static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 850{
 851        struct commit_list *list = NULL;
 852        struct commit_list *result = NULL;
 853        int i;
 854
 855        for (i = 0; i < n; i++) {
 856                if (one == twos[i])
 857                        /*
 858                         * We do not mark this even with RESULT so we do not
 859                         * have to clean it up.
 860                         */
 861                        return commit_list_insert(one, &result);
 862        }
 863
 864        if (parse_commit(one))
 865                return NULL;
 866        for (i = 0; i < n; i++) {
 867                if (parse_commit(twos[i]))
 868                        return NULL;
 869        }
 870
 871        list = paint_down_to_common(one, n, twos);
 872
 873        while (list) {
 874                struct commit_list *next = list->next;
 875                if (!(list->item->object.flags & STALE))
 876                        commit_list_insert_by_date(list->item, &result);
 877                free(list);
 878                list = next;
 879        }
 880        return result;
 881}
 882
 883struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 884{
 885        struct commit_list *i, *j, *k, *ret = NULL;
 886
 887        if (!in)
 888                return ret;
 889
 890        commit_list_insert(in->item, &ret);
 891
 892        for (i = in->next; i; i = i->next) {
 893                struct commit_list *new = NULL, *end = NULL;
 894
 895                for (j = ret; j; j = j->next) {
 896                        struct commit_list *bases;
 897                        bases = get_merge_bases(i->item, j->item, 1);
 898                        if (!new)
 899                                new = bases;
 900                        else
 901                                end->next = bases;
 902                        for (k = bases; k; k = k->next)
 903                                end = k;
 904                }
 905                ret = new;
 906        }
 907        return ret;
 908}
 909
 910static int remove_redundant(struct commit **array, int cnt)
 911{
 912        /*
 913         * Some commit in the array may be an ancestor of
 914         * another commit.  Move such commit to the end of
 915         * the array, and return the number of commits that
 916         * are independent from each other.
 917         */
 918        struct commit **work;
 919        unsigned char *redundant;
 920        int *filled_index;
 921        int i, j, filled;
 922
 923        work = xcalloc(cnt, sizeof(*work));
 924        redundant = xcalloc(cnt, 1);
 925        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 926
 927        for (i = 0; i < cnt; i++)
 928                parse_commit(array[i]);
 929        for (i = 0; i < cnt; i++) {
 930                struct commit_list *common;
 931
 932                if (redundant[i])
 933                        continue;
 934                for (j = filled = 0; j < cnt; j++) {
 935                        if (i == j || redundant[j])
 936                                continue;
 937                        filled_index[filled] = j;
 938                        work[filled++] = array[j];
 939                }
 940                common = paint_down_to_common(array[i], filled, work);
 941                if (array[i]->object.flags & PARENT2)
 942                        redundant[i] = 1;
 943                for (j = 0; j < filled; j++)
 944                        if (work[j]->object.flags & PARENT1)
 945                                redundant[filled_index[j]] = 1;
 946                clear_commit_marks(array[i], all_flags);
 947                for (j = 0; j < filled; j++)
 948                        clear_commit_marks(work[j], all_flags);
 949                free_commit_list(common);
 950        }
 951
 952        /* Now collect the result */
 953        memcpy(work, array, sizeof(*array) * cnt);
 954        for (i = filled = 0; i < cnt; i++)
 955                if (!redundant[i])
 956                        array[filled++] = work[i];
 957        for (j = filled, i = 0; i < cnt; i++)
 958                if (redundant[i])
 959                        array[j++] = work[i];
 960        free(work);
 961        free(redundant);
 962        free(filled_index);
 963        return filled;
 964}
 965
 966struct commit_list *get_merge_bases_many(struct commit *one,
 967                                         int n,
 968                                         struct commit **twos,
 969                                         int cleanup)
 970{
 971        struct commit_list *list;
 972        struct commit **rslt;
 973        struct commit_list *result;
 974        int cnt, i;
 975
 976        result = merge_bases_many(one, n, twos);
 977        for (i = 0; i < n; i++) {
 978                if (one == twos[i])
 979                        return result;
 980        }
 981        if (!result || !result->next) {
 982                if (cleanup) {
 983                        clear_commit_marks(one, all_flags);
 984                        clear_commit_marks_many(n, twos, all_flags);
 985                }
 986                return result;
 987        }
 988
 989        /* There are more than one */
 990        cnt = commit_list_count(result);
 991        rslt = xcalloc(cnt, sizeof(*rslt));
 992        for (list = result, i = 0; list; list = list->next)
 993                rslt[i++] = list->item;
 994        free_commit_list(result);
 995
 996        clear_commit_marks(one, all_flags);
 997        clear_commit_marks_many(n, twos, all_flags);
 998
 999        cnt = remove_redundant(rslt, cnt);
1000        result = NULL;
1001        for (i = 0; i < cnt; i++)
1002                commit_list_insert_by_date(rslt[i], &result);
1003        free(rslt);
1004        return result;
1005}
1006
1007struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
1008                                    int cleanup)
1009{
1010        return get_merge_bases_many(one, 1, &two, cleanup);
1011}
1012
1013/*
1014 * Is "commit" a descendant of one of the elements on the "with_commit" list?
1015 */
1016int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1017{
1018        if (!with_commit)
1019                return 1;
1020        while (with_commit) {
1021                struct commit *other;
1022
1023                other = with_commit->item;
1024                with_commit = with_commit->next;
1025                if (in_merge_bases(other, commit))
1026                        return 1;
1027        }
1028        return 0;
1029}
1030
1031/*
1032 * Is "commit" an ancestor of one of the "references"?
1033 */
1034int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1035{
1036        struct commit_list *bases;
1037        int ret = 0, i;
1038
1039        if (parse_commit(commit))
1040                return ret;
1041        for (i = 0; i < nr_reference; i++)
1042                if (parse_commit(reference[i]))
1043                        return ret;
1044
1045        bases = paint_down_to_common(commit, nr_reference, reference);
1046        if (commit->object.flags & PARENT2)
1047                ret = 1;
1048        clear_commit_marks(commit, all_flags);
1049        clear_commit_marks_many(nr_reference, reference, all_flags);
1050        free_commit_list(bases);
1051        return ret;
1052}
1053
1054/*
1055 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1056 */
1057int in_merge_bases(struct commit *commit, struct commit *reference)
1058{
1059        return in_merge_bases_many(commit, 1, &reference);
1060}
1061
1062struct commit_list *reduce_heads(struct commit_list *heads)
1063{
1064        struct commit_list *p;
1065        struct commit_list *result = NULL, **tail = &result;
1066        struct commit **array;
1067        int num_head, i;
1068
1069        if (!heads)
1070                return NULL;
1071
1072        /* Uniquify */
1073        for (p = heads; p; p = p->next)
1074                p->item->object.flags &= ~STALE;
1075        for (p = heads, num_head = 0; p; p = p->next) {
1076                if (p->item->object.flags & STALE)
1077                        continue;
1078                p->item->object.flags |= STALE;
1079                num_head++;
1080        }
1081        array = xcalloc(num_head, sizeof(*array));
1082        for (p = heads, i = 0; p; p = p->next) {
1083                if (p->item->object.flags & STALE) {
1084                        array[i++] = p->item;
1085                        p->item->object.flags &= ~STALE;
1086                }
1087        }
1088        num_head = remove_redundant(array, num_head);
1089        for (i = 0; i < num_head; i++)
1090                tail = &commit_list_insert(array[i], tail)->next;
1091        return result;
1092}
1093
1094static const char gpg_sig_header[] = "gpgsig";
1095static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1096
1097static int do_sign_commit(struct strbuf *buf, const char *keyid)
1098{
1099        struct strbuf sig = STRBUF_INIT;
1100        int inspos, copypos;
1101
1102        /* find the end of the header */
1103        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1104
1105        if (!keyid || !*keyid)
1106                keyid = get_signing_key();
1107        if (sign_buffer(buf, &sig, keyid)) {
1108                strbuf_release(&sig);
1109                return -1;
1110        }
1111
1112        for (copypos = 0; sig.buf[copypos]; ) {
1113                const char *bol = sig.buf + copypos;
1114                const char *eol = strchrnul(bol, '\n');
1115                int len = (eol - bol) + !!*eol;
1116
1117                if (!copypos) {
1118                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1119                        inspos += gpg_sig_header_len;
1120                }
1121                strbuf_insert(buf, inspos++, " ", 1);
1122                strbuf_insert(buf, inspos, bol, len);
1123                inspos += len;
1124                copypos += len;
1125        }
1126        strbuf_release(&sig);
1127        return 0;
1128}
1129
1130int parse_signed_commit(const struct commit *commit,
1131                        struct strbuf *payload, struct strbuf *signature)
1132{
1133
1134        unsigned long size;
1135        const char *buffer = get_commit_buffer(commit, &size);
1136        int in_signature, saw_signature = -1;
1137        const char *line, *tail;
1138
1139        line = buffer;
1140        tail = buffer + size;
1141        in_signature = 0;
1142        saw_signature = 0;
1143        while (line < tail) {
1144                const char *sig = NULL;
1145                const char *next = memchr(line, '\n', tail - line);
1146
1147                next = next ? next + 1 : tail;
1148                if (in_signature && line[0] == ' ')
1149                        sig = line + 1;
1150                else if (starts_with(line, gpg_sig_header) &&
1151                         line[gpg_sig_header_len] == ' ')
1152                        sig = line + gpg_sig_header_len + 1;
1153                if (sig) {
1154                        strbuf_add(signature, sig, next - sig);
1155                        saw_signature = 1;
1156                        in_signature = 1;
1157                } else {
1158                        if (*line == '\n')
1159                                /* dump the whole remainder of the buffer */
1160                                next = tail;
1161                        strbuf_add(payload, line, next - line);
1162                        in_signature = 0;
1163                }
1164                line = next;
1165        }
1166        unuse_commit_buffer(commit, buffer);
1167        return saw_signature;
1168}
1169
1170static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1171{
1172        struct merge_remote_desc *desc;
1173        struct commit_extra_header *mergetag;
1174        char *buf;
1175        unsigned long size, len;
1176        enum object_type type;
1177
1178        desc = merge_remote_util(parent);
1179        if (!desc || !desc->obj)
1180                return;
1181        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1182        if (!buf || type != OBJ_TAG)
1183                goto free_return;
1184        len = parse_signature(buf, size);
1185        if (size == len)
1186                goto free_return;
1187        /*
1188         * We could verify this signature and either omit the tag when
1189         * it does not validate, but the integrator may not have the
1190         * public key of the signer of the tag he is merging, while a
1191         * later auditor may have it while auditing, so let's not run
1192         * verify-signed-buffer here for now...
1193         *
1194         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1195         *      warn("warning: signed tag unverified.");
1196         */
1197        mergetag = xcalloc(1, sizeof(*mergetag));
1198        mergetag->key = xstrdup("mergetag");
1199        mergetag->value = buf;
1200        mergetag->len = size;
1201
1202        **tail = mergetag;
1203        *tail = &mergetag->next;
1204        return;
1205
1206free_return:
1207        free(buf);
1208}
1209
1210static struct {
1211        char result;
1212        const char *check;
1213} sigcheck_gpg_status[] = {
1214        { 'G', "\n[GNUPG:] GOODSIG " },
1215        { 'B', "\n[GNUPG:] BADSIG " },
1216        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1217        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1218};
1219
1220static void parse_gpg_output(struct signature_check *sigc)
1221{
1222        const char *buf = sigc->gpg_status;
1223        int i;
1224
1225        /* Iterate over all search strings */
1226        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1227                const char *found, *next;
1228
1229                if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
1230                        found = strstr(buf, sigcheck_gpg_status[i].check);
1231                        if (!found)
1232                                continue;
1233                        found += strlen(sigcheck_gpg_status[i].check);
1234                }
1235                sigc->result = sigcheck_gpg_status[i].result;
1236                /* The trust messages are not followed by key/signer information */
1237                if (sigc->result != 'U') {
1238                        sigc->key = xmemdupz(found, 16);
1239                        found += 17;
1240                        next = strchrnul(found, '\n');
1241                        sigc->signer = xmemdupz(found, next - found);
1242                }
1243        }
1244}
1245
1246void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1247{
1248        struct strbuf payload = STRBUF_INIT;
1249        struct strbuf signature = STRBUF_INIT;
1250        struct strbuf gpg_output = STRBUF_INIT;
1251        struct strbuf gpg_status = STRBUF_INIT;
1252        int status;
1253
1254        sigc->result = 'N';
1255
1256        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1257                goto out;
1258        status = verify_signed_buffer(payload.buf, payload.len,
1259                                      signature.buf, signature.len,
1260                                      &gpg_output, &gpg_status);
1261        if (status && !gpg_output.len)
1262                goto out;
1263        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1264        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1265        parse_gpg_output(sigc);
1266
1267 out:
1268        strbuf_release(&gpg_status);
1269        strbuf_release(&gpg_output);
1270        strbuf_release(&payload);
1271        strbuf_release(&signature);
1272}
1273
1274
1275
1276void append_merge_tag_headers(struct commit_list *parents,
1277                              struct commit_extra_header ***tail)
1278{
1279        while (parents) {
1280                struct commit *parent = parents->item;
1281                handle_signed_tag(parent, tail);
1282                parents = parents->next;
1283        }
1284}
1285
1286static void add_extra_header(struct strbuf *buffer,
1287                             struct commit_extra_header *extra)
1288{
1289        strbuf_addstr(buffer, extra->key);
1290        if (extra->len)
1291                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1292        else
1293                strbuf_addch(buffer, '\n');
1294}
1295
1296struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1297                                                      const char **exclude)
1298{
1299        struct commit_extra_header *extra = NULL;
1300        unsigned long size;
1301        const char *buffer = get_commit_buffer(commit, &size);
1302        extra = read_commit_extra_header_lines(buffer, size, exclude);
1303        unuse_commit_buffer(commit, buffer);
1304        return extra;
1305}
1306
1307static inline int standard_header_field(const char *field, size_t len)
1308{
1309        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1310                (len == 6 && !memcmp(field, "parent ", 7)) ||
1311                (len == 6 && !memcmp(field, "author ", 7)) ||
1312                (len == 9 && !memcmp(field, "committer ", 10)) ||
1313                (len == 8 && !memcmp(field, "encoding ", 9)));
1314}
1315
1316static int excluded_header_field(const char *field, size_t len, const char **exclude)
1317{
1318        if (!exclude)
1319                return 0;
1320
1321        while (*exclude) {
1322                size_t xlen = strlen(*exclude);
1323                if (len == xlen &&
1324                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1325                        return 1;
1326                exclude++;
1327        }
1328        return 0;
1329}
1330
1331static struct commit_extra_header *read_commit_extra_header_lines(
1332        const char *buffer, size_t size,
1333        const char **exclude)
1334{
1335        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1336        const char *line, *next, *eof, *eob;
1337        struct strbuf buf = STRBUF_INIT;
1338
1339        for (line = buffer, eob = line + size;
1340             line < eob && *line != '\n';
1341             line = next) {
1342                next = memchr(line, '\n', eob - line);
1343                next = next ? next + 1 : eob;
1344                if (*line == ' ') {
1345                        /* continuation */
1346                        if (it)
1347                                strbuf_add(&buf, line + 1, next - (line + 1));
1348                        continue;
1349                }
1350                if (it)
1351                        it->value = strbuf_detach(&buf, &it->len);
1352                strbuf_reset(&buf);
1353                it = NULL;
1354
1355                eof = strchr(line, ' ');
1356                if (next <= eof)
1357                        eof = next;
1358
1359                if (standard_header_field(line, eof - line) ||
1360                    excluded_header_field(line, eof - line, exclude))
1361                        continue;
1362
1363                it = xcalloc(1, sizeof(*it));
1364                it->key = xmemdupz(line, eof-line);
1365                *tail = it;
1366                tail = &it->next;
1367                if (eof + 1 < next)
1368                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1369        }
1370        if (it)
1371                it->value = strbuf_detach(&buf, &it->len);
1372        return extra;
1373}
1374
1375void free_commit_extra_headers(struct commit_extra_header *extra)
1376{
1377        while (extra) {
1378                struct commit_extra_header *next = extra->next;
1379                free(extra->key);
1380                free(extra->value);
1381                free(extra);
1382                extra = next;
1383        }
1384}
1385
1386int commit_tree(const char *msg, size_t msg_len,
1387                const unsigned char *tree,
1388                struct commit_list *parents, unsigned char *ret,
1389                const char *author, const char *sign_commit)
1390{
1391        struct commit_extra_header *extra = NULL, **tail = &extra;
1392        int result;
1393
1394        append_merge_tag_headers(parents, &tail);
1395        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1396                                      author, sign_commit, extra);
1397        free_commit_extra_headers(extra);
1398        return result;
1399}
1400
1401static int find_invalid_utf8(const char *buf, int len)
1402{
1403        int offset = 0;
1404        static const unsigned int max_codepoint[] = {
1405                0x7f, 0x7ff, 0xffff, 0x10ffff
1406        };
1407
1408        while (len) {
1409                unsigned char c = *buf++;
1410                int bytes, bad_offset;
1411                unsigned int codepoint;
1412                unsigned int min_val, max_val;
1413
1414                len--;
1415                offset++;
1416
1417                /* Simple US-ASCII? No worries. */
1418                if (c < 0x80)
1419                        continue;
1420
1421                bad_offset = offset-1;
1422
1423                /*
1424                 * Count how many more high bits set: that's how
1425                 * many more bytes this sequence should have.
1426                 */
1427                bytes = 0;
1428                while (c & 0x40) {
1429                        c <<= 1;
1430                        bytes++;
1431                }
1432
1433                /*
1434                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1435                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1436                 */
1437                if (bytes < 1 || 3 < bytes)
1438                        return bad_offset;
1439
1440                /* Do we *have* that many bytes? */
1441                if (len < bytes)
1442                        return bad_offset;
1443
1444                /*
1445                 * Place the encoded bits at the bottom of the value and compute the
1446                 * valid range.
1447                 */
1448                codepoint = (c & 0x7f) >> bytes;
1449                min_val = max_codepoint[bytes-1] + 1;
1450                max_val = max_codepoint[bytes];
1451
1452                offset += bytes;
1453                len -= bytes;
1454
1455                /* And verify that they are good continuation bytes */
1456                do {
1457                        codepoint <<= 6;
1458                        codepoint |= *buf & 0x3f;
1459                        if ((*buf++ & 0xc0) != 0x80)
1460                                return bad_offset;
1461                } while (--bytes);
1462
1463                /* Reject codepoints that are out of range for the sequence length. */
1464                if (codepoint < min_val || codepoint > max_val)
1465                        return bad_offset;
1466                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1467                if ((codepoint & 0x1ff800) == 0xd800)
1468                        return bad_offset;
1469                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1470                if ((codepoint & 0xfffe) == 0xfffe)
1471                        return bad_offset;
1472                /* So are anything in the range U+FDD0..U+FDEF. */
1473                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1474                        return bad_offset;
1475        }
1476        return -1;
1477}
1478
1479/*
1480 * This verifies that the buffer is in proper utf8 format.
1481 *
1482 * If it isn't, it assumes any non-utf8 characters are Latin1,
1483 * and does the conversion.
1484 */
1485static int verify_utf8(struct strbuf *buf)
1486{
1487        int ok = 1;
1488        long pos = 0;
1489
1490        for (;;) {
1491                int bad;
1492                unsigned char c;
1493                unsigned char replace[2];
1494
1495                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1496                if (bad < 0)
1497                        return ok;
1498                pos += bad;
1499                ok = 0;
1500                c = buf->buf[pos];
1501                strbuf_remove(buf, pos, 1);
1502
1503                /* We know 'c' must be in the range 128-255 */
1504                replace[0] = 0xc0 + (c >> 6);
1505                replace[1] = 0x80 + (c & 0x3f);
1506                strbuf_insert(buf, pos, replace, 2);
1507                pos += 2;
1508        }
1509}
1510
1511static const char commit_utf8_warn[] =
1512"Warning: commit message did not conform to UTF-8.\n"
1513"You may want to amend it after fixing the message, or set the config\n"
1514"variable i18n.commitencoding to the encoding your project uses.\n";
1515
1516int commit_tree_extended(const char *msg, size_t msg_len,
1517                         const unsigned char *tree,
1518                         struct commit_list *parents, unsigned char *ret,
1519                         const char *author, const char *sign_commit,
1520                         struct commit_extra_header *extra)
1521{
1522        int result;
1523        int encoding_is_utf8;
1524        struct strbuf buffer;
1525
1526        assert_sha1_type(tree, OBJ_TREE);
1527
1528        if (memchr(msg, '\0', msg_len))
1529                return error("a NUL byte in commit log message not allowed.");
1530
1531        /* Not having i18n.commitencoding is the same as having utf-8 */
1532        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1533
1534        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1535        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1536
1537        /*
1538         * NOTE! This ordering means that the same exact tree merged with a
1539         * different order of parents will be a _different_ changeset even
1540         * if everything else stays the same.
1541         */
1542        while (parents) {
1543                struct commit_list *next = parents->next;
1544                struct commit *parent = parents->item;
1545
1546                strbuf_addf(&buffer, "parent %s\n",
1547                            sha1_to_hex(parent->object.sha1));
1548                free(parents);
1549                parents = next;
1550        }
1551
1552        /* Person/date information */
1553        if (!author)
1554                author = git_author_info(IDENT_STRICT);
1555        strbuf_addf(&buffer, "author %s\n", author);
1556        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1557        if (!encoding_is_utf8)
1558                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1559
1560        while (extra) {
1561                add_extra_header(&buffer, extra);
1562                extra = extra->next;
1563        }
1564        strbuf_addch(&buffer, '\n');
1565
1566        /* And add the comment */
1567        strbuf_add(&buffer, msg, msg_len);
1568
1569        /* And check the encoding */
1570        if (encoding_is_utf8 && !verify_utf8(&buffer))
1571                fprintf(stderr, commit_utf8_warn);
1572
1573        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1574                return -1;
1575
1576        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1577        strbuf_release(&buffer);
1578        return result;
1579}
1580
1581struct commit *get_merge_parent(const char *name)
1582{
1583        struct object *obj;
1584        struct commit *commit;
1585        unsigned char sha1[20];
1586        if (get_sha1(name, sha1))
1587                return NULL;
1588        obj = parse_object(sha1);
1589        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1590        if (commit && !commit->util) {
1591                struct merge_remote_desc *desc;
1592                desc = xmalloc(sizeof(*desc));
1593                desc->obj = obj;
1594                desc->name = strdup(name);
1595                commit->util = desc;
1596        }
1597        return commit;
1598}
1599
1600/*
1601 * Append a commit to the end of the commit_list.
1602 *
1603 * next starts by pointing to the variable that holds the head of an
1604 * empty commit_list, and is updated to point to the "next" field of
1605 * the last item on the list as new commits are appended.
1606 *
1607 * Usage example:
1608 *
1609 *     struct commit_list *list;
1610 *     struct commit_list **next = &list;
1611 *
1612 *     next = commit_list_append(c1, next);
1613 *     next = commit_list_append(c2, next);
1614 *     assert(commit_list_count(list) == 2);
1615 *     return list;
1616 */
1617struct commit_list **commit_list_append(struct commit *commit,
1618                                        struct commit_list **next)
1619{
1620        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1621        new->item = commit;
1622        *next = new;
1623        new->next = NULL;
1624        return &new->next;
1625}
1626
1627void print_commit_list(struct commit_list *list,
1628                       const char *format_cur,
1629                       const char *format_last)
1630{
1631        for ( ; list; list = list->next) {
1632                const char *format = list->next ? format_cur : format_last;
1633                printf(format, sha1_to_hex(list->item->object.sha1));
1634        }
1635}