Andrew's git / gitweb.git / commit.c
?
commit.con commit Merge branch 'jk/alloc-commit-id-maint' into maint (5d7c37a)
   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
  21struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  22                                              int quiet)
  23{
  24        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  25
  26        if (!obj)
  27                return NULL;
  28        return object_as_type(obj, OBJ_COMMIT, quiet);
  29}
  30
  31struct commit *lookup_commit_reference(const unsigned char *sha1)
  32{
  33        return lookup_commit_reference_gently(sha1, 0);
  34}
  35
  36struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  37{
  38        struct commit *c = lookup_commit_reference(sha1);
  39        if (!c)
  40                die(_("could not parse %s"), ref_name);
  41        if (hashcmp(sha1, c->object.sha1)) {
  42                warning(_("%s %s is not a commit!"),
  43                        ref_name, sha1_to_hex(sha1));
  44        }
  45        return c;
  46}
  47
  48struct commit *lookup_commit(const unsigned char *sha1)
  49{
  50        struct object *obj = lookup_object(sha1);
  51        if (!obj)
  52                return create_object(sha1, alloc_commit_node());
  53        return object_as_type(obj, OBJ_COMMIT, 0);
  54}
  55
  56struct commit *lookup_commit_reference_by_name(const char *name)
  57{
  58        unsigned char sha1[20];
  59        struct commit *commit;
  60
  61        if (get_sha1_committish(name, sha1))
  62                return NULL;
  63        commit = lookup_commit_reference(sha1);
  64        if (parse_commit(commit))
  65                return NULL;
  66        return commit;
  67}
  68
  69static unsigned long parse_commit_date(const char *buf, const char *tail)
  70{
  71        const char *dateptr;
  72
  73        if (buf + 6 >= tail)
  74                return 0;
  75        if (memcmp(buf, "author", 6))
  76                return 0;
  77        while (buf < tail && *buf++ != '\n')
  78                /* nada */;
  79        if (buf + 9 >= tail)
  80                return 0;
  81        if (memcmp(buf, "committer", 9))
  82                return 0;
  83        while (buf < tail && *buf++ != '>')
  84                /* nada */;
  85        if (buf >= tail)
  86                return 0;
  87        dateptr = buf;
  88        while (buf < tail && *buf++ != '\n')
  89                /* nada */;
  90        if (buf >= tail)
  91                return 0;
  92        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  93        return strtoul(dateptr, NULL, 10);
  94}
  95
  96static struct commit_graft **commit_graft;
  97static int commit_graft_alloc, commit_graft_nr;
  98
  99static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 100{
 101        struct commit_graft **commit_graft_table = table;
 102        return commit_graft_table[index]->sha1;
 103}
 104
 105static int commit_graft_pos(const unsigned char *sha1)
 106{
 107        return sha1_pos(sha1, commit_graft, commit_graft_nr,
 108                        commit_graft_sha1_access);
 109}
 110
 111int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 112{
 113        int pos = commit_graft_pos(graft->sha1);
 114
 115        if (0 <= pos) {
 116                if (ignore_dups)
 117                        free(graft);
 118                else {
 119                        free(commit_graft[pos]);
 120                        commit_graft[pos] = graft;
 121                }
 122                return 1;
 123        }
 124        pos = -pos - 1;
 125        ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 126        commit_graft_nr++;
 127        if (pos < commit_graft_nr)
 128                memmove(commit_graft + pos + 1,
 129                        commit_graft + pos,
 130                        (commit_graft_nr - pos - 1) *
 131                        sizeof(*commit_graft));
 132        commit_graft[pos] = graft;
 133        return 0;
 134}
 135
 136struct commit_graft *read_graft_line(char *buf, int len)
 137{
 138        /* The format is just "Commit Parent1 Parent2 ...\n" */
 139        int i;
 140        struct commit_graft *graft = NULL;
 141
 142        while (len && isspace(buf[len-1]))
 143                buf[--len] = '\0';
 144        if (buf[0] == '#' || buf[0] == '\0')
 145                return NULL;
 146        if ((len + 1) % 41)
 147                goto bad_graft_data;
 148        i = (len + 1) / 41 - 1;
 149        graft = xmalloc(sizeof(*graft) + 20 * i);
 150        graft->nr_parent = i;
 151        if (get_sha1_hex(buf, graft->sha1))
 152                goto bad_graft_data;
 153        for (i = 40; i < len; i += 41) {
 154                if (buf[i] != ' ')
 155                        goto bad_graft_data;
 156                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 157                        goto bad_graft_data;
 158        }
 159        return graft;
 160
 161bad_graft_data:
 162        error("bad graft data: %s", buf);
 163        free(graft);
 164        return NULL;
 165}
 166
 167static int read_graft_file(const char *graft_file)
 168{
 169        FILE *fp = fopen(graft_file, "r");
 170        struct strbuf buf = STRBUF_INIT;
 171        if (!fp)
 172                return -1;
 173        while (!strbuf_getwholeline(&buf, fp, '\n')) {
 174                /* The format is just "Commit Parent1 Parent2 ...\n" */
 175                struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 176                if (!graft)
 177                        continue;
 178                if (register_commit_graft(graft, 1))
 179                        error("duplicate graft data: %s", buf.buf);
 180        }
 181        fclose(fp);
 182        strbuf_release(&buf);
 183        return 0;
 184}
 185
 186static void prepare_commit_graft(void)
 187{
 188        static int commit_graft_prepared;
 189        char *graft_file;
 190
 191        if (commit_graft_prepared)
 192                return;
 193        graft_file = get_graft_file();
 194        read_graft_file(graft_file);
 195        /* make sure shallows are read */
 196        is_repository_shallow();
 197        commit_graft_prepared = 1;
 198}
 199
 200struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 201{
 202        int pos;
 203        prepare_commit_graft();
 204        pos = commit_graft_pos(sha1);
 205        if (pos < 0)
 206                return NULL;
 207        return commit_graft[pos];
 208}
 209
 210int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 211{
 212        int i, ret;
 213        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 214                ret = fn(commit_graft[i], cb_data);
 215        return ret;
 216}
 217
 218int unregister_shallow(const unsigned char *sha1)
 219{
 220        int pos = commit_graft_pos(sha1);
 221        if (pos < 0)
 222                return -1;
 223        if (pos + 1 < commit_graft_nr)
 224                memmove(commit_graft + pos, commit_graft + pos + 1,
 225                                sizeof(struct commit_graft *)
 226                                * (commit_graft_nr - pos - 1));
 227        commit_graft_nr--;
 228        return 0;
 229}
 230
 231struct commit_buffer {
 232        void *buffer;
 233        unsigned long size;
 234};
 235define_commit_slab(buffer_slab, struct commit_buffer);
 236static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 237
 238void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
 239{
 240        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 241        v->buffer = buffer;
 242        v->size = size;
 243}
 244
 245const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
 246{
 247        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 248        if (sizep)
 249                *sizep = v->size;
 250        return v->buffer;
 251}
 252
 253const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 254{
 255        const void *ret = get_cached_commit_buffer(commit, sizep);
 256        if (!ret) {
 257                enum object_type type;
 258                unsigned long size;
 259                ret = read_sha1_file(commit->object.sha1, &type, &size);
 260                if (!ret)
 261                        die("cannot read commit object %s",
 262                            sha1_to_hex(commit->object.sha1));
 263                if (type != OBJ_COMMIT)
 264                        die("expected commit for %s, got %s",
 265                            sha1_to_hex(commit->object.sha1), typename(type));
 266                if (sizep)
 267                        *sizep = size;
 268        }
 269        return ret;
 270}
 271
 272void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 273{
 274        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 275        if (v->buffer != buffer)
 276                free((void *)buffer);
 277}
 278
 279void free_commit_buffer(struct commit *commit)
 280{
 281        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 282        free(v->buffer);
 283        v->buffer = NULL;
 284        v->size = 0;
 285}
 286
 287const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 288{
 289        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 290        void *ret;
 291
 292        ret = v->buffer;
 293        if (sizep)
 294                *sizep = v->size;
 295
 296        v->buffer = NULL;
 297        v->size = 0;
 298        return ret;
 299}
 300
 301int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 302{
 303        const char *tail = buffer;
 304        const char *bufptr = buffer;
 305        unsigned char parent[20];
 306        struct commit_list **pptr;
 307        struct commit_graft *graft;
 308
 309        if (item->object.parsed)
 310                return 0;
 311        item->object.parsed = 1;
 312        tail += size;
 313        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 314                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 315        if (get_sha1_hex(bufptr + 5, parent) < 0)
 316                return error("bad tree pointer in commit %s",
 317                             sha1_to_hex(item->object.sha1));
 318        item->tree = lookup_tree(parent);
 319        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 320        pptr = &item->parents;
 321
 322        graft = lookup_commit_graft(item->object.sha1);
 323        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 324                struct commit *new_parent;
 325
 326                if (tail <= bufptr + 48 ||
 327                    get_sha1_hex(bufptr + 7, parent) ||
 328                    bufptr[47] != '\n')
 329                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 330                bufptr += 48;
 331                /*
 332                 * The clone is shallow if nr_parent < 0, and we must
 333                 * not traverse its real parents even when we unhide them.
 334                 */
 335                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 336                        continue;
 337                new_parent = lookup_commit(parent);
 338                if (new_parent)
 339                        pptr = &commit_list_insert(new_parent, pptr)->next;
 340        }
 341        if (graft) {
 342                int i;
 343                struct commit *new_parent;
 344                for (i = 0; i < graft->nr_parent; i++) {
 345                        new_parent = lookup_commit(graft->parent[i]);
 346                        if (!new_parent)
 347                                continue;
 348                        pptr = &commit_list_insert(new_parent, pptr)->next;
 349                }
 350        }
 351        item->date = parse_commit_date(bufptr, tail);
 352
 353        return 0;
 354}
 355
 356int parse_commit(struct commit *item)
 357{
 358        enum object_type type;
 359        void *buffer;
 360        unsigned long size;
 361        int ret;
 362
 363        if (!item)
 364                return -1;
 365        if (item->object.parsed)
 366                return 0;
 367        buffer = read_sha1_file(item->object.sha1, &type, &size);
 368        if (!buffer)
 369                return error("Could not read %s",
 370                             sha1_to_hex(item->object.sha1));
 371        if (type != OBJ_COMMIT) {
 372                free(buffer);
 373                return error("Object %s not a commit",
 374                             sha1_to_hex(item->object.sha1));
 375        }
 376        ret = parse_commit_buffer(item, buffer, size);
 377        if (save_commit_buffer && !ret) {
 378                set_commit_buffer(item, buffer, size);
 379                return 0;
 380        }
 381        free(buffer);
 382        return ret;
 383}
 384
 385void parse_commit_or_die(struct commit *item)
 386{
 387        if (parse_commit(item))
 388                die("unable to parse commit %s",
 389                    item ? sha1_to_hex(item->object.sha1) : "(null)");
 390}
 391
 392int find_commit_subject(const char *commit_buffer, const char **subject)
 393{
 394        const char *eol;
 395        const char *p = commit_buffer;
 396
 397        while (*p && (*p != '\n' || p[1] != '\n'))
 398                p++;
 399        if (*p) {
 400                p += 2;
 401                for (eol = p; *eol && *eol != '\n'; eol++)
 402                        ; /* do nothing */
 403        } else
 404                eol = p;
 405
 406        *subject = p;
 407
 408        return eol - p;
 409}
 410
 411struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 412{
 413        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 414        new_list->item = item;
 415        new_list->next = *list_p;
 416        *list_p = new_list;
 417        return new_list;
 418}
 419
 420unsigned commit_list_count(const struct commit_list *l)
 421{
 422        unsigned c = 0;
 423        for (; l; l = l->next )
 424                c++;
 425        return c;
 426}
 427
 428struct commit_list *copy_commit_list(struct commit_list *list)
 429{
 430        struct commit_list *head = NULL;
 431        struct commit_list **pp = &head;
 432        while (list) {
 433                struct commit_list *new;
 434                new = xmalloc(sizeof(struct commit_list));
 435                new->item = list->item;
 436                new->next = NULL;
 437                *pp = new;
 438                pp = &new->next;
 439                list = list->next;
 440        }
 441        return head;
 442}
 443
 444void free_commit_list(struct commit_list *list)
 445{
 446        while (list) {
 447                struct commit_list *temp = list;
 448                list = temp->next;
 449                free(temp);
 450        }
 451}
 452
 453struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 454{
 455        struct commit_list **pp = list;
 456        struct commit_list *p;
 457        while ((p = *pp) != NULL) {
 458                if (p->item->date < item->date) {
 459                        break;
 460                }
 461                pp = &p->next;
 462        }
 463        return commit_list_insert(item, pp);
 464}
 465
 466static int commit_list_compare_by_date(const void *a, const void *b)
 467{
 468        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 469        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 470        if (a_date < b_date)
 471                return 1;
 472        if (a_date > b_date)
 473                return -1;
 474        return 0;
 475}
 476
 477static void *commit_list_get_next(const void *a)
 478{
 479        return ((const struct commit_list *)a)->next;
 480}
 481
 482static void commit_list_set_next(void *a, void *next)
 483{
 484        ((struct commit_list *)a)->next = next;
 485}
 486
 487void commit_list_sort_by_date(struct commit_list **list)
 488{
 489        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 490                                commit_list_compare_by_date);
 491}
 492
 493struct commit *pop_most_recent_commit(struct commit_list **list,
 494                                      unsigned int mark)
 495{
 496        struct commit *ret = (*list)->item;
 497        struct commit_list *parents = ret->parents;
 498        struct commit_list *old = *list;
 499
 500        *list = (*list)->next;
 501        free(old);
 502
 503        while (parents) {
 504                struct commit *commit = parents->item;
 505                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 506                        commit->object.flags |= mark;
 507                        commit_list_insert_by_date(commit, list);
 508                }
 509                parents = parents->next;
 510        }
 511        return ret;
 512}
 513
 514static void clear_commit_marks_1(struct commit_list **plist,
 515                                 struct commit *commit, unsigned int mark)
 516{
 517        while (commit) {
 518                struct commit_list *parents;
 519
 520                if (!(mark & commit->object.flags))
 521                        return;
 522
 523                commit->object.flags &= ~mark;
 524
 525                parents = commit->parents;
 526                if (!parents)
 527                        return;
 528
 529                while ((parents = parents->next))
 530                        commit_list_insert(parents->item, plist);
 531
 532                commit = commit->parents->item;
 533        }
 534}
 535
 536void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 537{
 538        struct commit_list *list = NULL;
 539
 540        while (nr--) {
 541                commit_list_insert(*commit, &list);
 542                commit++;
 543        }
 544        while (list)
 545                clear_commit_marks_1(&list, pop_commit(&list), mark);
 546}
 547
 548void clear_commit_marks(struct commit *commit, unsigned int mark)
 549{
 550        clear_commit_marks_many(1, &commit, mark);
 551}
 552
 553void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 554{
 555        struct object *object;
 556        struct commit *commit;
 557        unsigned int i;
 558
 559        for (i = 0; i < a->nr; i++) {
 560                object = a->objects[i].item;
 561                commit = lookup_commit_reference_gently(object->sha1, 1);
 562                if (commit)
 563                        clear_commit_marks(commit, mark);
 564        }
 565}
 566
 567struct commit *pop_commit(struct commit_list **stack)
 568{
 569        struct commit_list *top = *stack;
 570        struct commit *item = top ? top->item : NULL;
 571
 572        if (top) {
 573                *stack = top->next;
 574                free(top);
 575        }
 576        return item;
 577}
 578
 579/*
 580 * Topological sort support
 581 */
 582
 583/* count number of children that have not been emitted */
 584define_commit_slab(indegree_slab, int);
 585
 586/* record author-date for each commit object */
 587define_commit_slab(author_date_slab, unsigned long);
 588
 589static void record_author_date(struct author_date_slab *author_date,
 590                               struct commit *commit)
 591{
 592        const char *buf, *line_end, *ident_line;
 593        const char *buffer = get_commit_buffer(commit, NULL);
 594        struct ident_split ident;
 595        char *date_end;
 596        unsigned long date;
 597
 598        for (buf = buffer; buf; buf = line_end + 1) {
 599                line_end = strchrnul(buf, '\n');
 600                ident_line = skip_prefix(buf, "author ");
 601                if (!ident_line) {
 602                        if (!line_end[0] || line_end[1] == '\n')
 603                                return; /* end of header */
 604                        continue;
 605                }
 606                if (split_ident_line(&ident,
 607                                     ident_line, line_end - ident_line) ||
 608                    !ident.date_begin || !ident.date_end)
 609                        goto fail_exit; /* malformed "author" line */
 610                break;
 611        }
 612
 613        date = strtoul(ident.date_begin, &date_end, 10);
 614        if (date_end != ident.date_end)
 615                goto fail_exit; /* malformed date */
 616        *(author_date_slab_at(author_date, commit)) = date;
 617
 618fail_exit:
 619        unuse_commit_buffer(commit, buffer);
 620}
 621
 622static int compare_commits_by_author_date(const void *a_, const void *b_,
 623                                          void *cb_data)
 624{
 625        const struct commit *a = a_, *b = b_;
 626        struct author_date_slab *author_date = cb_data;
 627        unsigned long a_date = *(author_date_slab_at(author_date, a));
 628        unsigned long b_date = *(author_date_slab_at(author_date, b));
 629
 630        /* newer commits with larger date first */
 631        if (a_date < b_date)
 632                return 1;
 633        else if (a_date > b_date)
 634                return -1;
 635        return 0;
 636}
 637
 638int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 639{
 640        const struct commit *a = a_, *b = b_;
 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
 649/*
 650 * Performs an in-place topological sort on the list supplied.
 651 */
 652void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 653{
 654        struct commit_list *next, *orig = *list;
 655        struct commit_list **pptr;
 656        struct indegree_slab indegree;
 657        struct prio_queue queue;
 658        struct commit *commit;
 659        struct author_date_slab author_date;
 660
 661        if (!orig)
 662                return;
 663        *list = NULL;
 664
 665        init_indegree_slab(&indegree);
 666        memset(&queue, '\0', sizeof(queue));
 667
 668        switch (sort_order) {
 669        default: /* REV_SORT_IN_GRAPH_ORDER */
 670                queue.compare = NULL;
 671                break;
 672        case REV_SORT_BY_COMMIT_DATE:
 673                queue.compare = compare_commits_by_commit_date;
 674                break;
 675        case REV_SORT_BY_AUTHOR_DATE:
 676                init_author_date_slab(&author_date);
 677                queue.compare = compare_commits_by_author_date;
 678                queue.cb_data = &author_date;
 679                break;
 680        }
 681
 682        /* Mark them and clear the indegree */
 683        for (next = orig; next; next = next->next) {
 684                struct commit *commit = next->item;
 685                *(indegree_slab_at(&indegree, commit)) = 1;
 686                /* also record the author dates, if needed */
 687                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 688                        record_author_date(&author_date, commit);
 689        }
 690
 691        /* update the indegree */
 692        for (next = orig; next; next = next->next) {
 693                struct commit_list *parents = next->item->parents;
 694                while (parents) {
 695                        struct commit *parent = parents->item;
 696                        int *pi = indegree_slab_at(&indegree, parent);
 697
 698                        if (*pi)
 699                                (*pi)++;
 700                        parents = parents->next;
 701                }
 702        }
 703
 704        /*
 705         * find the tips
 706         *
 707         * tips are nodes not reachable from any other node in the list
 708         *
 709         * the tips serve as a starting set for the work queue.
 710         */
 711        for (next = orig; next; next = next->next) {
 712                struct commit *commit = next->item;
 713
 714                if (*(indegree_slab_at(&indegree, commit)) == 1)
 715                        prio_queue_put(&queue, commit);
 716        }
 717
 718        /*
 719         * This is unfortunate; the initial tips need to be shown
 720         * in the order given from the revision traversal machinery.
 721         */
 722        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 723                prio_queue_reverse(&queue);
 724
 725        /* We no longer need the commit list */
 726        free_commit_list(orig);
 727
 728        pptr = list;
 729        *list = NULL;
 730        while ((commit = prio_queue_get(&queue)) != NULL) {
 731                struct commit_list *parents;
 732
 733                for (parents = commit->parents; parents ; parents = parents->next) {
 734                        struct commit *parent = parents->item;
 735                        int *pi = indegree_slab_at(&indegree, parent);
 736
 737                        if (!*pi)
 738                                continue;
 739
 740                        /*
 741                         * parents are only enqueued for emission
 742                         * when all their children have been emitted thereby
 743                         * guaranteeing topological order.
 744                         */
 745                        if (--(*pi) == 1)
 746                                prio_queue_put(&queue, parent);
 747                }
 748                /*
 749                 * all children of commit have already been
 750                 * emitted. we can emit it now.
 751                 */
 752                *(indegree_slab_at(&indegree, commit)) = 0;
 753
 754                pptr = &commit_list_insert(commit, pptr)->next;
 755        }
 756
 757        clear_indegree_slab(&indegree);
 758        clear_prio_queue(&queue);
 759        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 760                clear_author_date_slab(&author_date);
 761}
 762
 763/* merge-base stuff */
 764
 765/* Remember to update object flag allocation in object.h */
 766#define PARENT1         (1u<<16)
 767#define PARENT2         (1u<<17)
 768#define STALE           (1u<<18)
 769#define RESULT          (1u<<19)
 770
 771static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 772
 773static struct commit *interesting(struct commit_list *list)
 774{
 775        while (list) {
 776                struct commit *commit = list->item;
 777                list = list->next;
 778                if (commit->object.flags & STALE)
 779                        continue;
 780                return commit;
 781        }
 782        return NULL;
 783}
 784
 785/* all input commits in one and twos[] must have been parsed! */
 786static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 787{
 788        struct commit_list *list = NULL;
 789        struct commit_list *result = NULL;
 790        int i;
 791
 792        one->object.flags |= PARENT1;
 793        commit_list_insert_by_date(one, &list);
 794        if (!n)
 795                return list;
 796        for (i = 0; i < n; i++) {
 797                twos[i]->object.flags |= PARENT2;
 798                commit_list_insert_by_date(twos[i], &list);
 799        }
 800
 801        while (interesting(list)) {
 802                struct commit *commit;
 803                struct commit_list *parents;
 804                struct commit_list *next;
 805                int flags;
 806
 807                commit = list->item;
 808                next = list->next;
 809                free(list);
 810                list = next;
 811
 812                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 813                if (flags == (PARENT1 | PARENT2)) {
 814                        if (!(commit->object.flags & RESULT)) {
 815                                commit->object.flags |= RESULT;
 816                                commit_list_insert_by_date(commit, &result);
 817                        }
 818                        /* Mark parents of a found merge stale */
 819                        flags |= STALE;
 820                }
 821                parents = commit->parents;
 822                while (parents) {
 823                        struct commit *p = parents->item;
 824                        parents = parents->next;
 825                        if ((p->object.flags & flags) == flags)
 826                                continue;
 827                        if (parse_commit(p))
 828                                return NULL;
 829                        p->object.flags |= flags;
 830                        commit_list_insert_by_date(p, &list);
 831                }
 832        }
 833
 834        free_commit_list(list);
 835        return result;
 836}
 837
 838static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 839{
 840        struct commit_list *list = NULL;
 841        struct commit_list *result = NULL;
 842        int i;
 843
 844        for (i = 0; i < n; i++) {
 845                if (one == twos[i])
 846                        /*
 847                         * We do not mark this even with RESULT so we do not
 848                         * have to clean it up.
 849                         */
 850                        return commit_list_insert(one, &result);
 851        }
 852
 853        if (parse_commit(one))
 854                return NULL;
 855        for (i = 0; i < n; i++) {
 856                if (parse_commit(twos[i]))
 857                        return NULL;
 858        }
 859
 860        list = paint_down_to_common(one, n, twos);
 861
 862        while (list) {
 863                struct commit_list *next = list->next;
 864                if (!(list->item->object.flags & STALE))
 865                        commit_list_insert_by_date(list->item, &result);
 866                free(list);
 867                list = next;
 868        }
 869        return result;
 870}
 871
 872struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 873{
 874        struct commit_list *i, *j, *k, *ret = NULL;
 875
 876        if (!in)
 877                return ret;
 878
 879        commit_list_insert(in->item, &ret);
 880
 881        for (i = in->next; i; i = i->next) {
 882                struct commit_list *new = NULL, *end = NULL;
 883
 884                for (j = ret; j; j = j->next) {
 885                        struct commit_list *bases;
 886                        bases = get_merge_bases(i->item, j->item, 1);
 887                        if (!new)
 888                                new = bases;
 889                        else
 890                                end->next = bases;
 891                        for (k = bases; k; k = k->next)
 892                                end = k;
 893                }
 894                ret = new;
 895        }
 896        return ret;
 897}
 898
 899static int remove_redundant(struct commit **array, int cnt)
 900{
 901        /*
 902         * Some commit in the array may be an ancestor of
 903         * another commit.  Move such commit to the end of
 904         * the array, and return the number of commits that
 905         * are independent from each other.
 906         */
 907        struct commit **work;
 908        unsigned char *redundant;
 909        int *filled_index;
 910        int i, j, filled;
 911
 912        work = xcalloc(cnt, sizeof(*work));
 913        redundant = xcalloc(cnt, 1);
 914        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 915
 916        for (i = 0; i < cnt; i++)
 917                parse_commit(array[i]);
 918        for (i = 0; i < cnt; i++) {
 919                struct commit_list *common;
 920
 921                if (redundant[i])
 922                        continue;
 923                for (j = filled = 0; j < cnt; j++) {
 924                        if (i == j || redundant[j])
 925                                continue;
 926                        filled_index[filled] = j;
 927                        work[filled++] = array[j];
 928                }
 929                common = paint_down_to_common(array[i], filled, work);
 930                if (array[i]->object.flags & PARENT2)
 931                        redundant[i] = 1;
 932                for (j = 0; j < filled; j++)
 933                        if (work[j]->object.flags & PARENT1)
 934                                redundant[filled_index[j]] = 1;
 935                clear_commit_marks(array[i], all_flags);
 936                for (j = 0; j < filled; j++)
 937                        clear_commit_marks(work[j], all_flags);
 938                free_commit_list(common);
 939        }
 940
 941        /* Now collect the result */
 942        memcpy(work, array, sizeof(*array) * cnt);
 943        for (i = filled = 0; i < cnt; i++)
 944                if (!redundant[i])
 945                        array[filled++] = work[i];
 946        for (j = filled, i = 0; i < cnt; i++)
 947                if (redundant[i])
 948                        array[j++] = work[i];
 949        free(work);
 950        free(redundant);
 951        free(filled_index);
 952        return filled;
 953}
 954
 955struct commit_list *get_merge_bases_many(struct commit *one,
 956                                         int n,
 957                                         struct commit **twos,
 958                                         int cleanup)
 959{
 960        struct commit_list *list;
 961        struct commit **rslt;
 962        struct commit_list *result;
 963        int cnt, i;
 964
 965        result = merge_bases_many(one, n, twos);
 966        for (i = 0; i < n; i++) {
 967                if (one == twos[i])
 968                        return result;
 969        }
 970        if (!result || !result->next) {
 971                if (cleanup) {
 972                        clear_commit_marks(one, all_flags);
 973                        clear_commit_marks_many(n, twos, all_flags);
 974                }
 975                return result;
 976        }
 977
 978        /* There are more than one */
 979        cnt = 0;
 980        list = result;
 981        while (list) {
 982                list = list->next;
 983                cnt++;
 984        }
 985        rslt = xcalloc(cnt, sizeof(*rslt));
 986        for (list = result, i = 0; list; list = list->next)
 987                rslt[i++] = list->item;
 988        free_commit_list(result);
 989
 990        clear_commit_marks(one, all_flags);
 991        clear_commit_marks_many(n, twos, all_flags);
 992
 993        cnt = remove_redundant(rslt, cnt);
 994        result = NULL;
 995        for (i = 0; i < cnt; i++)
 996                commit_list_insert_by_date(rslt[i], &result);
 997        free(rslt);
 998        return result;
 999}
1000
1001struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
1002                                    int cleanup)
1003{
1004        return get_merge_bases_many(one, 1, &two, cleanup);
1005}
1006
1007/*
1008 * Is "commit" a descendant of one of the elements on the "with_commit" list?
1009 */
1010int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1011{
1012        if (!with_commit)
1013                return 1;
1014        while (with_commit) {
1015                struct commit *other;
1016
1017                other = with_commit->item;
1018                with_commit = with_commit->next;
1019                if (in_merge_bases(other, commit))
1020                        return 1;
1021        }
1022        return 0;
1023}
1024
1025/*
1026 * Is "commit" an ancestor of one of the "references"?
1027 */
1028int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1029{
1030        struct commit_list *bases;
1031        int ret = 0, i;
1032
1033        if (parse_commit(commit))
1034                return ret;
1035        for (i = 0; i < nr_reference; i++)
1036                if (parse_commit(reference[i]))
1037                        return ret;
1038
1039        bases = paint_down_to_common(commit, nr_reference, reference);
1040        if (commit->object.flags & PARENT2)
1041                ret = 1;
1042        clear_commit_marks(commit, all_flags);
1043        clear_commit_marks_many(nr_reference, reference, all_flags);
1044        free_commit_list(bases);
1045        return ret;
1046}
1047
1048/*
1049 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1050 */
1051int in_merge_bases(struct commit *commit, struct commit *reference)
1052{
1053        return in_merge_bases_many(commit, 1, &reference);
1054}
1055
1056struct commit_list *reduce_heads(struct commit_list *heads)
1057{
1058        struct commit_list *p;
1059        struct commit_list *result = NULL, **tail = &result;
1060        struct commit **array;
1061        int num_head, i;
1062
1063        if (!heads)
1064                return NULL;
1065
1066        /* Uniquify */
1067        for (p = heads; p; p = p->next)
1068                p->item->object.flags &= ~STALE;
1069        for (p = heads, num_head = 0; p; p = p->next) {
1070                if (p->item->object.flags & STALE)
1071                        continue;
1072                p->item->object.flags |= STALE;
1073                num_head++;
1074        }
1075        array = xcalloc(num_head, sizeof(*array));
1076        for (p = heads, i = 0; p; p = p->next) {
1077                if (p->item->object.flags & STALE) {
1078                        array[i++] = p->item;
1079                        p->item->object.flags &= ~STALE;
1080                }
1081        }
1082        num_head = remove_redundant(array, num_head);
1083        for (i = 0; i < num_head; i++)
1084                tail = &commit_list_insert(array[i], tail)->next;
1085        return result;
1086}
1087
1088static const char gpg_sig_header[] = "gpgsig";
1089static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1090
1091static int do_sign_commit(struct strbuf *buf, const char *keyid)
1092{
1093        struct strbuf sig = STRBUF_INIT;
1094        int inspos, copypos;
1095
1096        /* find the end of the header */
1097        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1098
1099        if (!keyid || !*keyid)
1100                keyid = get_signing_key();
1101        if (sign_buffer(buf, &sig, keyid)) {
1102                strbuf_release(&sig);
1103                return -1;
1104        }
1105
1106        for (copypos = 0; sig.buf[copypos]; ) {
1107                const char *bol = sig.buf + copypos;
1108                const char *eol = strchrnul(bol, '\n');
1109                int len = (eol - bol) + !!*eol;
1110
1111                if (!copypos) {
1112                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1113                        inspos += gpg_sig_header_len;
1114                }
1115                strbuf_insert(buf, inspos++, " ", 1);
1116                strbuf_insert(buf, inspos, bol, len);
1117                inspos += len;
1118                copypos += len;
1119        }
1120        strbuf_release(&sig);
1121        return 0;
1122}
1123
1124int parse_signed_commit(const struct commit *commit,
1125                        struct strbuf *payload, struct strbuf *signature)
1126{
1127
1128        unsigned long size;
1129        const char *buffer = get_commit_buffer(commit, &size);
1130        int in_signature, saw_signature = -1;
1131        const char *line, *tail;
1132
1133        line = buffer;
1134        tail = buffer + size;
1135        in_signature = 0;
1136        saw_signature = 0;
1137        while (line < tail) {
1138                const char *sig = NULL;
1139                const char *next = memchr(line, '\n', tail - line);
1140
1141                next = next ? next + 1 : tail;
1142                if (in_signature && line[0] == ' ')
1143                        sig = line + 1;
1144                else if (starts_with(line, gpg_sig_header) &&
1145                         line[gpg_sig_header_len] == ' ')
1146                        sig = line + gpg_sig_header_len + 1;
1147                if (sig) {
1148                        strbuf_add(signature, sig, next - sig);
1149                        saw_signature = 1;
1150                        in_signature = 1;
1151                } else {
1152                        if (*line == '\n')
1153                                /* dump the whole remainder of the buffer */
1154                                next = tail;
1155                        strbuf_add(payload, line, next - line);
1156                        in_signature = 0;
1157                }
1158                line = next;
1159        }
1160        unuse_commit_buffer(commit, buffer);
1161        return saw_signature;
1162}
1163
1164static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1165{
1166        struct merge_remote_desc *desc;
1167        struct commit_extra_header *mergetag;
1168        char *buf;
1169        unsigned long size, len;
1170        enum object_type type;
1171
1172        desc = merge_remote_util(parent);
1173        if (!desc || !desc->obj)
1174                return;
1175        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1176        if (!buf || type != OBJ_TAG)
1177                goto free_return;
1178        len = parse_signature(buf, size);
1179        if (size == len)
1180                goto free_return;
1181        /*
1182         * We could verify this signature and either omit the tag when
1183         * it does not validate, but the integrator may not have the
1184         * public key of the signer of the tag he is merging, while a
1185         * later auditor may have it while auditing, so let's not run
1186         * verify-signed-buffer here for now...
1187         *
1188         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1189         *      warn("warning: signed tag unverified.");
1190         */
1191        mergetag = xcalloc(1, sizeof(*mergetag));
1192        mergetag->key = xstrdup("mergetag");
1193        mergetag->value = buf;
1194        mergetag->len = size;
1195
1196        **tail = mergetag;
1197        *tail = &mergetag->next;
1198        return;
1199
1200free_return:
1201        free(buf);
1202}
1203
1204static struct {
1205        char result;
1206        const char *check;
1207} sigcheck_gpg_status[] = {
1208        { 'G', "\n[GNUPG:] GOODSIG " },
1209        { 'B', "\n[GNUPG:] BADSIG " },
1210        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1211        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1212};
1213
1214static void parse_gpg_output(struct signature_check *sigc)
1215{
1216        const char *buf = sigc->gpg_status;
1217        int i;
1218
1219        /* Iterate over all search strings */
1220        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1221                const char *found, *next;
1222
1223                found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
1224                if (!found) {
1225                        found = strstr(buf, sigcheck_gpg_status[i].check);
1226                        if (!found)
1227                                continue;
1228                        found += strlen(sigcheck_gpg_status[i].check);
1229                }
1230                sigc->result = sigcheck_gpg_status[i].result;
1231                /* The trust messages are not followed by key/signer information */
1232                if (sigc->result != 'U') {
1233                        sigc->key = xmemdupz(found, 16);
1234                        found += 17;
1235                        next = strchrnul(found, '\n');
1236                        sigc->signer = xmemdupz(found, next - found);
1237                }
1238        }
1239}
1240
1241void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1242{
1243        struct strbuf payload = STRBUF_INIT;
1244        struct strbuf signature = STRBUF_INIT;
1245        struct strbuf gpg_output = STRBUF_INIT;
1246        struct strbuf gpg_status = STRBUF_INIT;
1247        int status;
1248
1249        sigc->result = 'N';
1250
1251        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1252                goto out;
1253        status = verify_signed_buffer(payload.buf, payload.len,
1254                                      signature.buf, signature.len,
1255                                      &gpg_output, &gpg_status);
1256        if (status && !gpg_output.len)
1257                goto out;
1258        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1259        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1260        parse_gpg_output(sigc);
1261
1262 out:
1263        strbuf_release(&gpg_status);
1264        strbuf_release(&gpg_output);
1265        strbuf_release(&payload);
1266        strbuf_release(&signature);
1267}
1268
1269
1270
1271void append_merge_tag_headers(struct commit_list *parents,
1272                              struct commit_extra_header ***tail)
1273{
1274        while (parents) {
1275                struct commit *parent = parents->item;
1276                handle_signed_tag(parent, tail);
1277                parents = parents->next;
1278        }
1279}
1280
1281static void add_extra_header(struct strbuf *buffer,
1282                             struct commit_extra_header *extra)
1283{
1284        strbuf_addstr(buffer, extra->key);
1285        if (extra->len)
1286                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1287        else
1288                strbuf_addch(buffer, '\n');
1289}
1290
1291struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1292                                                      const char **exclude)
1293{
1294        struct commit_extra_header *extra = NULL;
1295        unsigned long size;
1296        const char *buffer = get_commit_buffer(commit, &size);
1297        extra = read_commit_extra_header_lines(buffer, size, exclude);
1298        unuse_commit_buffer(commit, buffer);
1299        return extra;
1300}
1301
1302static inline int standard_header_field(const char *field, size_t len)
1303{
1304        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1305                (len == 6 && !memcmp(field, "parent ", 7)) ||
1306                (len == 6 && !memcmp(field, "author ", 7)) ||
1307                (len == 9 && !memcmp(field, "committer ", 10)) ||
1308                (len == 8 && !memcmp(field, "encoding ", 9)));
1309}
1310
1311static int excluded_header_field(const char *field, size_t len, const char **exclude)
1312{
1313        if (!exclude)
1314                return 0;
1315
1316        while (*exclude) {
1317                size_t xlen = strlen(*exclude);
1318                if (len == xlen &&
1319                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1320                        return 1;
1321                exclude++;
1322        }
1323        return 0;
1324}
1325
1326static struct commit_extra_header *read_commit_extra_header_lines(
1327        const char *buffer, size_t size,
1328        const char **exclude)
1329{
1330        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1331        const char *line, *next, *eof, *eob;
1332        struct strbuf buf = STRBUF_INIT;
1333
1334        for (line = buffer, eob = line + size;
1335             line < eob && *line != '\n';
1336             line = next) {
1337                next = memchr(line, '\n', eob - line);
1338                next = next ? next + 1 : eob;
1339                if (*line == ' ') {
1340                        /* continuation */
1341                        if (it)
1342                                strbuf_add(&buf, line + 1, next - (line + 1));
1343                        continue;
1344                }
1345                if (it)
1346                        it->value = strbuf_detach(&buf, &it->len);
1347                strbuf_reset(&buf);
1348                it = NULL;
1349
1350                eof = strchr(line, ' ');
1351                if (next <= eof)
1352                        eof = next;
1353
1354                if (standard_header_field(line, eof - line) ||
1355                    excluded_header_field(line, eof - line, exclude))
1356                        continue;
1357
1358                it = xcalloc(1, sizeof(*it));
1359                it->key = xmemdupz(line, eof-line);
1360                *tail = it;
1361                tail = &it->next;
1362                if (eof + 1 < next)
1363                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1364        }
1365        if (it)
1366                it->value = strbuf_detach(&buf, &it->len);
1367        return extra;
1368}
1369
1370void free_commit_extra_headers(struct commit_extra_header *extra)
1371{
1372        while (extra) {
1373                struct commit_extra_header *next = extra->next;
1374                free(extra->key);
1375                free(extra->value);
1376                free(extra);
1377                extra = next;
1378        }
1379}
1380
1381int commit_tree(const char *msg, size_t msg_len,
1382                const unsigned char *tree,
1383                struct commit_list *parents, unsigned char *ret,
1384                const char *author, const char *sign_commit)
1385{
1386        struct commit_extra_header *extra = NULL, **tail = &extra;
1387        int result;
1388
1389        append_merge_tag_headers(parents, &tail);
1390        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1391                                      author, sign_commit, extra);
1392        free_commit_extra_headers(extra);
1393        return result;
1394}
1395
1396static int find_invalid_utf8(const char *buf, int len)
1397{
1398        int offset = 0;
1399        static const unsigned int max_codepoint[] = {
1400                0x7f, 0x7ff, 0xffff, 0x10ffff
1401        };
1402
1403        while (len) {
1404                unsigned char c = *buf++;
1405                int bytes, bad_offset;
1406                unsigned int codepoint;
1407                unsigned int min_val, max_val;
1408
1409                len--;
1410                offset++;
1411
1412                /* Simple US-ASCII? No worries. */
1413                if (c < 0x80)
1414                        continue;
1415
1416                bad_offset = offset-1;
1417
1418                /*
1419                 * Count how many more high bits set: that's how
1420                 * many more bytes this sequence should have.
1421                 */
1422                bytes = 0;
1423                while (c & 0x40) {
1424                        c <<= 1;
1425                        bytes++;
1426                }
1427
1428                /*
1429                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1430                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1431                 */
1432                if (bytes < 1 || 3 < bytes)
1433                        return bad_offset;
1434
1435                /* Do we *have* that many bytes? */
1436                if (len < bytes)
1437                        return bad_offset;
1438
1439                /*
1440                 * Place the encoded bits at the bottom of the value and compute the
1441                 * valid range.
1442                 */
1443                codepoint = (c & 0x7f) >> bytes;
1444                min_val = max_codepoint[bytes-1] + 1;
1445                max_val = max_codepoint[bytes];
1446
1447                offset += bytes;
1448                len -= bytes;
1449
1450                /* And verify that they are good continuation bytes */
1451                do {
1452                        codepoint <<= 6;
1453                        codepoint |= *buf & 0x3f;
1454                        if ((*buf++ & 0xc0) != 0x80)
1455                                return bad_offset;
1456                } while (--bytes);
1457
1458                /* Reject codepoints that are out of range for the sequence length. */
1459                if (codepoint < min_val || codepoint > max_val)
1460                        return bad_offset;
1461                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1462                if ((codepoint & 0x1ff800) == 0xd800)
1463                        return bad_offset;
1464                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1465                if ((codepoint & 0xfffe) == 0xfffe)
1466                        return bad_offset;
1467                /* So are anything in the range U+FDD0..U+FDEF. */
1468                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1469                        return bad_offset;
1470        }
1471        return -1;
1472}
1473
1474/*
1475 * This verifies that the buffer is in proper utf8 format.
1476 *
1477 * If it isn't, it assumes any non-utf8 characters are Latin1,
1478 * and does the conversion.
1479 */
1480static int verify_utf8(struct strbuf *buf)
1481{
1482        int ok = 1;
1483        long pos = 0;
1484
1485        for (;;) {
1486                int bad;
1487                unsigned char c;
1488                unsigned char replace[2];
1489
1490                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1491                if (bad < 0)
1492                        return ok;
1493                pos += bad;
1494                ok = 0;
1495                c = buf->buf[pos];
1496                strbuf_remove(buf, pos, 1);
1497
1498                /* We know 'c' must be in the range 128-255 */
1499                replace[0] = 0xc0 + (c >> 6);
1500                replace[1] = 0x80 + (c & 0x3f);
1501                strbuf_insert(buf, pos, replace, 2);
1502                pos += 2;
1503        }
1504}
1505
1506static const char commit_utf8_warn[] =
1507"Warning: commit message did not conform to UTF-8.\n"
1508"You may want to amend it after fixing the message, or set the config\n"
1509"variable i18n.commitencoding to the encoding your project uses.\n";
1510
1511int commit_tree_extended(const char *msg, size_t msg_len,
1512                         const unsigned char *tree,
1513                         struct commit_list *parents, unsigned char *ret,
1514                         const char *author, const char *sign_commit,
1515                         struct commit_extra_header *extra)
1516{
1517        int result;
1518        int encoding_is_utf8;
1519        struct strbuf buffer;
1520
1521        assert_sha1_type(tree, OBJ_TREE);
1522
1523        if (memchr(msg, '\0', msg_len))
1524                return error("a NUL byte in commit log message not allowed.");
1525
1526        /* Not having i18n.commitencoding is the same as having utf-8 */
1527        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1528
1529        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1530        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1531
1532        /*
1533         * NOTE! This ordering means that the same exact tree merged with a
1534         * different order of parents will be a _different_ changeset even
1535         * if everything else stays the same.
1536         */
1537        while (parents) {
1538                struct commit_list *next = parents->next;
1539                struct commit *parent = parents->item;
1540
1541                strbuf_addf(&buffer, "parent %s\n",
1542                            sha1_to_hex(parent->object.sha1));
1543                free(parents);
1544                parents = next;
1545        }
1546
1547        /* Person/date information */
1548        if (!author)
1549                author = git_author_info(IDENT_STRICT);
1550        strbuf_addf(&buffer, "author %s\n", author);
1551        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1552        if (!encoding_is_utf8)
1553                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1554
1555        while (extra) {
1556                add_extra_header(&buffer, extra);
1557                extra = extra->next;
1558        }
1559        strbuf_addch(&buffer, '\n');
1560
1561        /* And add the comment */
1562        strbuf_add(&buffer, msg, msg_len);
1563
1564        /* And check the encoding */
1565        if (encoding_is_utf8 && !verify_utf8(&buffer))
1566                fprintf(stderr, commit_utf8_warn);
1567
1568        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1569                return -1;
1570
1571        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1572        strbuf_release(&buffer);
1573        return result;
1574}
1575
1576struct commit *get_merge_parent(const char *name)
1577{
1578        struct object *obj;
1579        struct commit *commit;
1580        unsigned char sha1[20];
1581        if (get_sha1(name, sha1))
1582                return NULL;
1583        obj = parse_object(sha1);
1584        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1585        if (commit && !commit->util) {
1586                struct merge_remote_desc *desc;
1587                desc = xmalloc(sizeof(*desc));
1588                desc->obj = obj;
1589                desc->name = strdup(name);
1590                commit->util = desc;
1591        }
1592        return commit;
1593}
1594
1595/*
1596 * Append a commit to the end of the commit_list.
1597 *
1598 * next starts by pointing to the variable that holds the head of an
1599 * empty commit_list, and is updated to point to the "next" field of
1600 * the last item on the list as new commits are appended.
1601 *
1602 * Usage example:
1603 *
1604 *     struct commit_list *list;
1605 *     struct commit_list **next = &list;
1606 *
1607 *     next = commit_list_append(c1, next);
1608 *     next = commit_list_append(c2, next);
1609 *     assert(commit_list_count(list) == 2);
1610 *     return list;
1611 */
1612struct commit_list **commit_list_append(struct commit *commit,
1613                                        struct commit_list **next)
1614{
1615        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1616        new->item = commit;
1617        *next = new;
1618        new->next = NULL;
1619        return &new->next;
1620}
1621
1622void print_commit_list(struct commit_list *list,
1623                       const char *format_cur,
1624                       const char *format_last)
1625{
1626        for ( ; list; list = list->next) {
1627                const char *format = list->next ? format_cur : format_last;
1628                printf(format, sha1_to_hex(list->item->object.sha1));
1629        }
1630}