Andrew's git / gitweb.git / commit.c
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commit.con commit Merge branch 'rs/unify-is-branch' (528396a)
   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 = 0;
 991        list = result;
 992        while (list) {
 993                list = list->next;
 994                cnt++;
 995        }
 996        rslt = xcalloc(cnt, sizeof(*rslt));
 997        for (list = result, i = 0; list; list = list->next)
 998                rslt[i++] = list->item;
 999        free_commit_list(result);
1000
1001        clear_commit_marks(one, all_flags);
1002        clear_commit_marks_many(n, twos, all_flags);
1003
1004        cnt = remove_redundant(rslt, cnt);
1005        result = NULL;
1006        for (i = 0; i < cnt; i++)
1007                commit_list_insert_by_date(rslt[i], &result);
1008        free(rslt);
1009        return result;
1010}
1011
1012struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
1013                                    int cleanup)
1014{
1015        return get_merge_bases_many(one, 1, &two, cleanup);
1016}
1017
1018/*
1019 * Is "commit" a descendant of one of the elements on the "with_commit" list?
1020 */
1021int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1022{
1023        if (!with_commit)
1024                return 1;
1025        while (with_commit) {
1026                struct commit *other;
1027
1028                other = with_commit->item;
1029                with_commit = with_commit->next;
1030                if (in_merge_bases(other, commit))
1031                        return 1;
1032        }
1033        return 0;
1034}
1035
1036/*
1037 * Is "commit" an ancestor of one of the "references"?
1038 */
1039int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1040{
1041        struct commit_list *bases;
1042        int ret = 0, i;
1043
1044        if (parse_commit(commit))
1045                return ret;
1046        for (i = 0; i < nr_reference; i++)
1047                if (parse_commit(reference[i]))
1048                        return ret;
1049
1050        bases = paint_down_to_common(commit, nr_reference, reference);
1051        if (commit->object.flags & PARENT2)
1052                ret = 1;
1053        clear_commit_marks(commit, all_flags);
1054        clear_commit_marks_many(nr_reference, reference, all_flags);
1055        free_commit_list(bases);
1056        return ret;
1057}
1058
1059/*
1060 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1061 */
1062int in_merge_bases(struct commit *commit, struct commit *reference)
1063{
1064        return in_merge_bases_many(commit, 1, &reference);
1065}
1066
1067struct commit_list *reduce_heads(struct commit_list *heads)
1068{
1069        struct commit_list *p;
1070        struct commit_list *result = NULL, **tail = &result;
1071        struct commit **array;
1072        int num_head, i;
1073
1074        if (!heads)
1075                return NULL;
1076
1077        /* Uniquify */
1078        for (p = heads; p; p = p->next)
1079                p->item->object.flags &= ~STALE;
1080        for (p = heads, num_head = 0; p; p = p->next) {
1081                if (p->item->object.flags & STALE)
1082                        continue;
1083                p->item->object.flags |= STALE;
1084                num_head++;
1085        }
1086        array = xcalloc(num_head, sizeof(*array));
1087        for (p = heads, i = 0; p; p = p->next) {
1088                if (p->item->object.flags & STALE) {
1089                        array[i++] = p->item;
1090                        p->item->object.flags &= ~STALE;
1091                }
1092        }
1093        num_head = remove_redundant(array, num_head);
1094        for (i = 0; i < num_head; i++)
1095                tail = &commit_list_insert(array[i], tail)->next;
1096        return result;
1097}
1098
1099static const char gpg_sig_header[] = "gpgsig";
1100static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1101
1102static int do_sign_commit(struct strbuf *buf, const char *keyid)
1103{
1104        struct strbuf sig = STRBUF_INIT;
1105        int inspos, copypos;
1106
1107        /* find the end of the header */
1108        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1109
1110        if (!keyid || !*keyid)
1111                keyid = get_signing_key();
1112        if (sign_buffer(buf, &sig, keyid)) {
1113                strbuf_release(&sig);
1114                return -1;
1115        }
1116
1117        for (copypos = 0; sig.buf[copypos]; ) {
1118                const char *bol = sig.buf + copypos;
1119                const char *eol = strchrnul(bol, '\n');
1120                int len = (eol - bol) + !!*eol;
1121
1122                if (!copypos) {
1123                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1124                        inspos += gpg_sig_header_len;
1125                }
1126                strbuf_insert(buf, inspos++, " ", 1);
1127                strbuf_insert(buf, inspos, bol, len);
1128                inspos += len;
1129                copypos += len;
1130        }
1131        strbuf_release(&sig);
1132        return 0;
1133}
1134
1135int parse_signed_commit(const struct commit *commit,
1136                        struct strbuf *payload, struct strbuf *signature)
1137{
1138
1139        unsigned long size;
1140        const char *buffer = get_commit_buffer(commit, &size);
1141        int in_signature, saw_signature = -1;
1142        const char *line, *tail;
1143
1144        line = buffer;
1145        tail = buffer + size;
1146        in_signature = 0;
1147        saw_signature = 0;
1148        while (line < tail) {
1149                const char *sig = NULL;
1150                const char *next = memchr(line, '\n', tail - line);
1151
1152                next = next ? next + 1 : tail;
1153                if (in_signature && line[0] == ' ')
1154                        sig = line + 1;
1155                else if (starts_with(line, gpg_sig_header) &&
1156                         line[gpg_sig_header_len] == ' ')
1157                        sig = line + gpg_sig_header_len + 1;
1158                if (sig) {
1159                        strbuf_add(signature, sig, next - sig);
1160                        saw_signature = 1;
1161                        in_signature = 1;
1162                } else {
1163                        if (*line == '\n')
1164                                /* dump the whole remainder of the buffer */
1165                                next = tail;
1166                        strbuf_add(payload, line, next - line);
1167                        in_signature = 0;
1168                }
1169                line = next;
1170        }
1171        unuse_commit_buffer(commit, buffer);
1172        return saw_signature;
1173}
1174
1175static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1176{
1177        struct merge_remote_desc *desc;
1178        struct commit_extra_header *mergetag;
1179        char *buf;
1180        unsigned long size, len;
1181        enum object_type type;
1182
1183        desc = merge_remote_util(parent);
1184        if (!desc || !desc->obj)
1185                return;
1186        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1187        if (!buf || type != OBJ_TAG)
1188                goto free_return;
1189        len = parse_signature(buf, size);
1190        if (size == len)
1191                goto free_return;
1192        /*
1193         * We could verify this signature and either omit the tag when
1194         * it does not validate, but the integrator may not have the
1195         * public key of the signer of the tag he is merging, while a
1196         * later auditor may have it while auditing, so let's not run
1197         * verify-signed-buffer here for now...
1198         *
1199         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1200         *      warn("warning: signed tag unverified.");
1201         */
1202        mergetag = xcalloc(1, sizeof(*mergetag));
1203        mergetag->key = xstrdup("mergetag");
1204        mergetag->value = buf;
1205        mergetag->len = size;
1206
1207        **tail = mergetag;
1208        *tail = &mergetag->next;
1209        return;
1210
1211free_return:
1212        free(buf);
1213}
1214
1215static struct {
1216        char result;
1217        const char *check;
1218} sigcheck_gpg_status[] = {
1219        { 'G', "\n[GNUPG:] GOODSIG " },
1220        { 'B', "\n[GNUPG:] BADSIG " },
1221        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1222        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1223};
1224
1225static void parse_gpg_output(struct signature_check *sigc)
1226{
1227        const char *buf = sigc->gpg_status;
1228        int i;
1229
1230        /* Iterate over all search strings */
1231        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1232                const char *found, *next;
1233
1234                if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
1235                        found = strstr(buf, sigcheck_gpg_status[i].check);
1236                        if (!found)
1237                                continue;
1238                        found += strlen(sigcheck_gpg_status[i].check);
1239                }
1240                sigc->result = sigcheck_gpg_status[i].result;
1241                /* The trust messages are not followed by key/signer information */
1242                if (sigc->result != 'U') {
1243                        sigc->key = xmemdupz(found, 16);
1244                        found += 17;
1245                        next = strchrnul(found, '\n');
1246                        sigc->signer = xmemdupz(found, next - found);
1247                }
1248        }
1249}
1250
1251void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1252{
1253        struct strbuf payload = STRBUF_INIT;
1254        struct strbuf signature = STRBUF_INIT;
1255        struct strbuf gpg_output = STRBUF_INIT;
1256        struct strbuf gpg_status = STRBUF_INIT;
1257        int status;
1258
1259        sigc->result = 'N';
1260
1261        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1262                goto out;
1263        status = verify_signed_buffer(payload.buf, payload.len,
1264                                      signature.buf, signature.len,
1265                                      &gpg_output, &gpg_status);
1266        if (status && !gpg_output.len)
1267                goto out;
1268        sigc->payload = strbuf_detach(&payload, NULL);
1269        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1270        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1271        parse_gpg_output(sigc);
1272
1273 out:
1274        strbuf_release(&gpg_status);
1275        strbuf_release(&gpg_output);
1276        strbuf_release(&payload);
1277        strbuf_release(&signature);
1278}
1279
1280
1281
1282void append_merge_tag_headers(struct commit_list *parents,
1283                              struct commit_extra_header ***tail)
1284{
1285        while (parents) {
1286                struct commit *parent = parents->item;
1287                handle_signed_tag(parent, tail);
1288                parents = parents->next;
1289        }
1290}
1291
1292static void add_extra_header(struct strbuf *buffer,
1293                             struct commit_extra_header *extra)
1294{
1295        strbuf_addstr(buffer, extra->key);
1296        if (extra->len)
1297                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1298        else
1299                strbuf_addch(buffer, '\n');
1300}
1301
1302struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1303                                                      const char **exclude)
1304{
1305        struct commit_extra_header *extra = NULL;
1306        unsigned long size;
1307        const char *buffer = get_commit_buffer(commit, &size);
1308        extra = read_commit_extra_header_lines(buffer, size, exclude);
1309        unuse_commit_buffer(commit, buffer);
1310        return extra;
1311}
1312
1313void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1314{
1315        struct commit_extra_header *extra, *to_free;
1316
1317        to_free = read_commit_extra_headers(commit, NULL);
1318        for (extra = to_free; extra; extra = extra->next) {
1319                if (strcmp(extra->key, "mergetag"))
1320                        continue; /* not a merge tag */
1321                fn(commit, extra, data);
1322        }
1323        free_commit_extra_headers(to_free);
1324}
1325
1326static inline int standard_header_field(const char *field, size_t len)
1327{
1328        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1329                (len == 6 && !memcmp(field, "parent ", 7)) ||
1330                (len == 6 && !memcmp(field, "author ", 7)) ||
1331                (len == 9 && !memcmp(field, "committer ", 10)) ||
1332                (len == 8 && !memcmp(field, "encoding ", 9)));
1333}
1334
1335static int excluded_header_field(const char *field, size_t len, const char **exclude)
1336{
1337        if (!exclude)
1338                return 0;
1339
1340        while (*exclude) {
1341                size_t xlen = strlen(*exclude);
1342                if (len == xlen &&
1343                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1344                        return 1;
1345                exclude++;
1346        }
1347        return 0;
1348}
1349
1350static struct commit_extra_header *read_commit_extra_header_lines(
1351        const char *buffer, size_t size,
1352        const char **exclude)
1353{
1354        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1355        const char *line, *next, *eof, *eob;
1356        struct strbuf buf = STRBUF_INIT;
1357
1358        for (line = buffer, eob = line + size;
1359             line < eob && *line != '\n';
1360             line = next) {
1361                next = memchr(line, '\n', eob - line);
1362                next = next ? next + 1 : eob;
1363                if (*line == ' ') {
1364                        /* continuation */
1365                        if (it)
1366                                strbuf_add(&buf, line + 1, next - (line + 1));
1367                        continue;
1368                }
1369                if (it)
1370                        it->value = strbuf_detach(&buf, &it->len);
1371                strbuf_reset(&buf);
1372                it = NULL;
1373
1374                eof = strchr(line, ' ');
1375                if (next <= eof)
1376                        eof = next;
1377
1378                if (standard_header_field(line, eof - line) ||
1379                    excluded_header_field(line, eof - line, exclude))
1380                        continue;
1381
1382                it = xcalloc(1, sizeof(*it));
1383                it->key = xmemdupz(line, eof-line);
1384                *tail = it;
1385                tail = &it->next;
1386                if (eof + 1 < next)
1387                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1388        }
1389        if (it)
1390                it->value = strbuf_detach(&buf, &it->len);
1391        return extra;
1392}
1393
1394void free_commit_extra_headers(struct commit_extra_header *extra)
1395{
1396        while (extra) {
1397                struct commit_extra_header *next = extra->next;
1398                free(extra->key);
1399                free(extra->value);
1400                free(extra);
1401                extra = next;
1402        }
1403}
1404
1405int commit_tree(const char *msg, size_t msg_len,
1406                const unsigned char *tree,
1407                struct commit_list *parents, unsigned char *ret,
1408                const char *author, const char *sign_commit)
1409{
1410        struct commit_extra_header *extra = NULL, **tail = &extra;
1411        int result;
1412
1413        append_merge_tag_headers(parents, &tail);
1414        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1415                                      author, sign_commit, extra);
1416        free_commit_extra_headers(extra);
1417        return result;
1418}
1419
1420static int find_invalid_utf8(const char *buf, int len)
1421{
1422        int offset = 0;
1423        static const unsigned int max_codepoint[] = {
1424                0x7f, 0x7ff, 0xffff, 0x10ffff
1425        };
1426
1427        while (len) {
1428                unsigned char c = *buf++;
1429                int bytes, bad_offset;
1430                unsigned int codepoint;
1431                unsigned int min_val, max_val;
1432
1433                len--;
1434                offset++;
1435
1436                /* Simple US-ASCII? No worries. */
1437                if (c < 0x80)
1438                        continue;
1439
1440                bad_offset = offset-1;
1441
1442                /*
1443                 * Count how many more high bits set: that's how
1444                 * many more bytes this sequence should have.
1445                 */
1446                bytes = 0;
1447                while (c & 0x40) {
1448                        c <<= 1;
1449                        bytes++;
1450                }
1451
1452                /*
1453                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1454                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1455                 */
1456                if (bytes < 1 || 3 < bytes)
1457                        return bad_offset;
1458
1459                /* Do we *have* that many bytes? */
1460                if (len < bytes)
1461                        return bad_offset;
1462
1463                /*
1464                 * Place the encoded bits at the bottom of the value and compute the
1465                 * valid range.
1466                 */
1467                codepoint = (c & 0x7f) >> bytes;
1468                min_val = max_codepoint[bytes-1] + 1;
1469                max_val = max_codepoint[bytes];
1470
1471                offset += bytes;
1472                len -= bytes;
1473
1474                /* And verify that they are good continuation bytes */
1475                do {
1476                        codepoint <<= 6;
1477                        codepoint |= *buf & 0x3f;
1478                        if ((*buf++ & 0xc0) != 0x80)
1479                                return bad_offset;
1480                } while (--bytes);
1481
1482                /* Reject codepoints that are out of range for the sequence length. */
1483                if (codepoint < min_val || codepoint > max_val)
1484                        return bad_offset;
1485                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1486                if ((codepoint & 0x1ff800) == 0xd800)
1487                        return bad_offset;
1488                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1489                if ((codepoint & 0xfffe) == 0xfffe)
1490                        return bad_offset;
1491                /* So are anything in the range U+FDD0..U+FDEF. */
1492                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1493                        return bad_offset;
1494        }
1495        return -1;
1496}
1497
1498/*
1499 * This verifies that the buffer is in proper utf8 format.
1500 *
1501 * If it isn't, it assumes any non-utf8 characters are Latin1,
1502 * and does the conversion.
1503 */
1504static int verify_utf8(struct strbuf *buf)
1505{
1506        int ok = 1;
1507        long pos = 0;
1508
1509        for (;;) {
1510                int bad;
1511                unsigned char c;
1512                unsigned char replace[2];
1513
1514                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1515                if (bad < 0)
1516                        return ok;
1517                pos += bad;
1518                ok = 0;
1519                c = buf->buf[pos];
1520                strbuf_remove(buf, pos, 1);
1521
1522                /* We know 'c' must be in the range 128-255 */
1523                replace[0] = 0xc0 + (c >> 6);
1524                replace[1] = 0x80 + (c & 0x3f);
1525                strbuf_insert(buf, pos, replace, 2);
1526                pos += 2;
1527        }
1528}
1529
1530static const char commit_utf8_warn[] =
1531"Warning: commit message did not conform to UTF-8.\n"
1532"You may want to amend it after fixing the message, or set the config\n"
1533"variable i18n.commitencoding to the encoding your project uses.\n";
1534
1535int commit_tree_extended(const char *msg, size_t msg_len,
1536                         const unsigned char *tree,
1537                         struct commit_list *parents, unsigned char *ret,
1538                         const char *author, const char *sign_commit,
1539                         struct commit_extra_header *extra)
1540{
1541        int result;
1542        int encoding_is_utf8;
1543        struct strbuf buffer;
1544
1545        assert_sha1_type(tree, OBJ_TREE);
1546
1547        if (memchr(msg, '\0', msg_len))
1548                return error("a NUL byte in commit log message not allowed.");
1549
1550        /* Not having i18n.commitencoding is the same as having utf-8 */
1551        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1552
1553        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1554        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1555
1556        /*
1557         * NOTE! This ordering means that the same exact tree merged with a
1558         * different order of parents will be a _different_ changeset even
1559         * if everything else stays the same.
1560         */
1561        while (parents) {
1562                struct commit_list *next = parents->next;
1563                struct commit *parent = parents->item;
1564
1565                strbuf_addf(&buffer, "parent %s\n",
1566                            sha1_to_hex(parent->object.sha1));
1567                free(parents);
1568                parents = next;
1569        }
1570
1571        /* Person/date information */
1572        if (!author)
1573                author = git_author_info(IDENT_STRICT);
1574        strbuf_addf(&buffer, "author %s\n", author);
1575        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1576        if (!encoding_is_utf8)
1577                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1578
1579        while (extra) {
1580                add_extra_header(&buffer, extra);
1581                extra = extra->next;
1582        }
1583        strbuf_addch(&buffer, '\n');
1584
1585        /* And add the comment */
1586        strbuf_add(&buffer, msg, msg_len);
1587
1588        /* And check the encoding */
1589        if (encoding_is_utf8 && !verify_utf8(&buffer))
1590                fprintf(stderr, commit_utf8_warn);
1591
1592        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1593                return -1;
1594
1595        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1596        strbuf_release(&buffer);
1597        return result;
1598}
1599
1600struct commit *get_merge_parent(const char *name)
1601{
1602        struct object *obj;
1603        struct commit *commit;
1604        unsigned char sha1[20];
1605        if (get_sha1(name, sha1))
1606                return NULL;
1607        obj = parse_object(sha1);
1608        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1609        if (commit && !commit->util) {
1610                struct merge_remote_desc *desc;
1611                desc = xmalloc(sizeof(*desc));
1612                desc->obj = obj;
1613                desc->name = strdup(name);
1614                commit->util = desc;
1615        }
1616        return commit;
1617}
1618
1619/*
1620 * Append a commit to the end of the commit_list.
1621 *
1622 * next starts by pointing to the variable that holds the head of an
1623 * empty commit_list, and is updated to point to the "next" field of
1624 * the last item on the list as new commits are appended.
1625 *
1626 * Usage example:
1627 *
1628 *     struct commit_list *list;
1629 *     struct commit_list **next = &list;
1630 *
1631 *     next = commit_list_append(c1, next);
1632 *     next = commit_list_append(c2, next);
1633 *     assert(commit_list_count(list) == 2);
1634 *     return list;
1635 */
1636struct commit_list **commit_list_append(struct commit *commit,
1637                                        struct commit_list **next)
1638{
1639        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1640        new->item = commit;
1641        *next = new;
1642        new->next = NULL;
1643        return &new->next;
1644}
1645
1646void print_commit_list(struct commit_list *list,
1647                       const char *format_cur,
1648                       const char *format_last)
1649{
1650        for ( ; list; list = list->next) {
1651                const char *format = list->next ? format_cur : format_last;
1652                printf(format, sha1_to_hex(list->item->object.sha1));
1653        }
1654}