Andrew's git / gitweb.git / commit.c
?
commit.con commit Merge branch 'ep/shell-assign-and-export-vars' into maint (63618af)
   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                struct commit_list *new;
 451                new = xmalloc(sizeof(struct commit_list));
 452                new->item = list->item;
 453                new->next = NULL;
 454                *pp = new;
 455                pp = &new->next;
 456                list = list->next;
 457        }
 458        return head;
 459}
 460
 461void free_commit_list(struct commit_list *list)
 462{
 463        while (list) {
 464                struct commit_list *temp = list;
 465                list = temp->next;
 466                free(temp);
 467        }
 468}
 469
 470struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 471{
 472        struct commit_list **pp = list;
 473        struct commit_list *p;
 474        while ((p = *pp) != NULL) {
 475                if (p->item->date < item->date) {
 476                        break;
 477                }
 478                pp = &p->next;
 479        }
 480        return commit_list_insert(item, pp);
 481}
 482
 483static int commit_list_compare_by_date(const void *a, const void *b)
 484{
 485        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 486        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 487        if (a_date < b_date)
 488                return 1;
 489        if (a_date > b_date)
 490                return -1;
 491        return 0;
 492}
 493
 494static void *commit_list_get_next(const void *a)
 495{
 496        return ((const struct commit_list *)a)->next;
 497}
 498
 499static void commit_list_set_next(void *a, void *next)
 500{
 501        ((struct commit_list *)a)->next = next;
 502}
 503
 504void commit_list_sort_by_date(struct commit_list **list)
 505{
 506        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 507                                commit_list_compare_by_date);
 508}
 509
 510struct commit *pop_most_recent_commit(struct commit_list **list,
 511                                      unsigned int mark)
 512{
 513        struct commit *ret = (*list)->item;
 514        struct commit_list *parents = ret->parents;
 515        struct commit_list *old = *list;
 516
 517        *list = (*list)->next;
 518        free(old);
 519
 520        while (parents) {
 521                struct commit *commit = parents->item;
 522                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 523                        commit->object.flags |= mark;
 524                        commit_list_insert_by_date(commit, list);
 525                }
 526                parents = parents->next;
 527        }
 528        return ret;
 529}
 530
 531static void clear_commit_marks_1(struct commit_list **plist,
 532                                 struct commit *commit, unsigned int mark)
 533{
 534        while (commit) {
 535                struct commit_list *parents;
 536
 537                if (!(mark & commit->object.flags))
 538                        return;
 539
 540                commit->object.flags &= ~mark;
 541
 542                parents = commit->parents;
 543                if (!parents)
 544                        return;
 545
 546                while ((parents = parents->next))
 547                        commit_list_insert(parents->item, plist);
 548
 549                commit = commit->parents->item;
 550        }
 551}
 552
 553void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 554{
 555        struct commit_list *list = NULL;
 556
 557        while (nr--) {
 558                commit_list_insert(*commit, &list);
 559                commit++;
 560        }
 561        while (list)
 562                clear_commit_marks_1(&list, pop_commit(&list), mark);
 563}
 564
 565void clear_commit_marks(struct commit *commit, unsigned int mark)
 566{
 567        clear_commit_marks_many(1, &commit, mark);
 568}
 569
 570void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 571{
 572        struct object *object;
 573        struct commit *commit;
 574        unsigned int i;
 575
 576        for (i = 0; i < a->nr; i++) {
 577                object = a->objects[i].item;
 578                commit = lookup_commit_reference_gently(object->sha1, 1);
 579                if (commit)
 580                        clear_commit_marks(commit, mark);
 581        }
 582}
 583
 584struct commit *pop_commit(struct commit_list **stack)
 585{
 586        struct commit_list *top = *stack;
 587        struct commit *item = top ? top->item : NULL;
 588
 589        if (top) {
 590                *stack = top->next;
 591                free(top);
 592        }
 593        return item;
 594}
 595
 596/*
 597 * Topological sort support
 598 */
 599
 600/* count number of children that have not been emitted */
 601define_commit_slab(indegree_slab, int);
 602
 603/* record author-date for each commit object */
 604define_commit_slab(author_date_slab, unsigned long);
 605
 606static void record_author_date(struct author_date_slab *author_date,
 607                               struct commit *commit)
 608{
 609        const char *buf, *line_end, *ident_line;
 610        const char *buffer = get_commit_buffer(commit, NULL);
 611        struct ident_split ident;
 612        char *date_end;
 613        unsigned long date;
 614
 615        for (buf = buffer; buf; buf = line_end + 1) {
 616                line_end = strchrnul(buf, '\n');
 617                ident_line = skip_prefix(buf, "author ");
 618                if (!ident_line) {
 619                        if (!line_end[0] || line_end[1] == '\n')
 620                                return; /* end of header */
 621                        continue;
 622                }
 623                if (split_ident_line(&ident,
 624                                     ident_line, line_end - ident_line) ||
 625                    !ident.date_begin || !ident.date_end)
 626                        goto fail_exit; /* malformed "author" line */
 627                break;
 628        }
 629
 630        date = strtoul(ident.date_begin, &date_end, 10);
 631        if (date_end != ident.date_end)
 632                goto fail_exit; /* malformed date */
 633        *(author_date_slab_at(author_date, commit)) = date;
 634
 635fail_exit:
 636        unuse_commit_buffer(commit, buffer);
 637}
 638
 639static int compare_commits_by_author_date(const void *a_, const void *b_,
 640                                          void *cb_data)
 641{
 642        const struct commit *a = a_, *b = b_;
 643        struct author_date_slab *author_date = cb_data;
 644        unsigned long a_date = *(author_date_slab_at(author_date, a));
 645        unsigned long b_date = *(author_date_slab_at(author_date, b));
 646
 647        /* newer commits with larger date first */
 648        if (a_date < b_date)
 649                return 1;
 650        else if (a_date > b_date)
 651                return -1;
 652        return 0;
 653}
 654
 655int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 656{
 657        const struct commit *a = a_, *b = b_;
 658        /* newer commits with larger date first */
 659        if (a->date < b->date)
 660                return 1;
 661        else if (a->date > b->date)
 662                return -1;
 663        return 0;
 664}
 665
 666/*
 667 * Performs an in-place topological sort on the list supplied.
 668 */
 669void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 670{
 671        struct commit_list *next, *orig = *list;
 672        struct commit_list **pptr;
 673        struct indegree_slab indegree;
 674        struct prio_queue queue;
 675        struct commit *commit;
 676        struct author_date_slab author_date;
 677
 678        if (!orig)
 679                return;
 680        *list = NULL;
 681
 682        init_indegree_slab(&indegree);
 683        memset(&queue, '\0', sizeof(queue));
 684
 685        switch (sort_order) {
 686        default: /* REV_SORT_IN_GRAPH_ORDER */
 687                queue.compare = NULL;
 688                break;
 689        case REV_SORT_BY_COMMIT_DATE:
 690                queue.compare = compare_commits_by_commit_date;
 691                break;
 692        case REV_SORT_BY_AUTHOR_DATE:
 693                init_author_date_slab(&author_date);
 694                queue.compare = compare_commits_by_author_date;
 695                queue.cb_data = &author_date;
 696                break;
 697        }
 698
 699        /* Mark them and clear the indegree */
 700        for (next = orig; next; next = next->next) {
 701                struct commit *commit = next->item;
 702                *(indegree_slab_at(&indegree, commit)) = 1;
 703                /* also record the author dates, if needed */
 704                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 705                        record_author_date(&author_date, commit);
 706        }
 707
 708        /* update the indegree */
 709        for (next = orig; next; next = next->next) {
 710                struct commit_list *parents = next->item->parents;
 711                while (parents) {
 712                        struct commit *parent = parents->item;
 713                        int *pi = indegree_slab_at(&indegree, parent);
 714
 715                        if (*pi)
 716                                (*pi)++;
 717                        parents = parents->next;
 718                }
 719        }
 720
 721        /*
 722         * find the tips
 723         *
 724         * tips are nodes not reachable from any other node in the list
 725         *
 726         * the tips serve as a starting set for the work queue.
 727         */
 728        for (next = orig; next; next = next->next) {
 729                struct commit *commit = next->item;
 730
 731                if (*(indegree_slab_at(&indegree, commit)) == 1)
 732                        prio_queue_put(&queue, commit);
 733        }
 734
 735        /*
 736         * This is unfortunate; the initial tips need to be shown
 737         * in the order given from the revision traversal machinery.
 738         */
 739        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 740                prio_queue_reverse(&queue);
 741
 742        /* We no longer need the commit list */
 743        free_commit_list(orig);
 744
 745        pptr = list;
 746        *list = NULL;
 747        while ((commit = prio_queue_get(&queue)) != NULL) {
 748                struct commit_list *parents;
 749
 750                for (parents = commit->parents; parents ; parents = parents->next) {
 751                        struct commit *parent = parents->item;
 752                        int *pi = indegree_slab_at(&indegree, parent);
 753
 754                        if (!*pi)
 755                                continue;
 756
 757                        /*
 758                         * parents are only enqueued for emission
 759                         * when all their children have been emitted thereby
 760                         * guaranteeing topological order.
 761                         */
 762                        if (--(*pi) == 1)
 763                                prio_queue_put(&queue, parent);
 764                }
 765                /*
 766                 * all children of commit have already been
 767                 * emitted. we can emit it now.
 768                 */
 769                *(indegree_slab_at(&indegree, commit)) = 0;
 770
 771                pptr = &commit_list_insert(commit, pptr)->next;
 772        }
 773
 774        clear_indegree_slab(&indegree);
 775        clear_prio_queue(&queue);
 776        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 777                clear_author_date_slab(&author_date);
 778}
 779
 780/* merge-base stuff */
 781
 782/* Remember to update object flag allocation in object.h */
 783#define PARENT1         (1u<<16)
 784#define PARENT2         (1u<<17)
 785#define STALE           (1u<<18)
 786#define RESULT          (1u<<19)
 787
 788static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 789
 790static struct commit *interesting(struct commit_list *list)
 791{
 792        while (list) {
 793                struct commit *commit = list->item;
 794                list = list->next;
 795                if (commit->object.flags & STALE)
 796                        continue;
 797                return commit;
 798        }
 799        return NULL;
 800}
 801
 802/* all input commits in one and twos[] must have been parsed! */
 803static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 804{
 805        struct commit_list *list = NULL;
 806        struct commit_list *result = NULL;
 807        int i;
 808
 809        one->object.flags |= PARENT1;
 810        commit_list_insert_by_date(one, &list);
 811        if (!n)
 812                return list;
 813        for (i = 0; i < n; i++) {
 814                twos[i]->object.flags |= PARENT2;
 815                commit_list_insert_by_date(twos[i], &list);
 816        }
 817
 818        while (interesting(list)) {
 819                struct commit *commit;
 820                struct commit_list *parents;
 821                struct commit_list *next;
 822                int flags;
 823
 824                commit = list->item;
 825                next = list->next;
 826                free(list);
 827                list = next;
 828
 829                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 830                if (flags == (PARENT1 | PARENT2)) {
 831                        if (!(commit->object.flags & RESULT)) {
 832                                commit->object.flags |= RESULT;
 833                                commit_list_insert_by_date(commit, &result);
 834                        }
 835                        /* Mark parents of a found merge stale */
 836                        flags |= STALE;
 837                }
 838                parents = commit->parents;
 839                while (parents) {
 840                        struct commit *p = parents->item;
 841                        parents = parents->next;
 842                        if ((p->object.flags & flags) == flags)
 843                                continue;
 844                        if (parse_commit(p))
 845                                return NULL;
 846                        p->object.flags |= flags;
 847                        commit_list_insert_by_date(p, &list);
 848                }
 849        }
 850
 851        free_commit_list(list);
 852        return result;
 853}
 854
 855static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 856{
 857        struct commit_list *list = NULL;
 858        struct commit_list *result = NULL;
 859        int i;
 860
 861        for (i = 0; i < n; i++) {
 862                if (one == twos[i])
 863                        /*
 864                         * We do not mark this even with RESULT so we do not
 865                         * have to clean it up.
 866                         */
 867                        return commit_list_insert(one, &result);
 868        }
 869
 870        if (parse_commit(one))
 871                return NULL;
 872        for (i = 0; i < n; i++) {
 873                if (parse_commit(twos[i]))
 874                        return NULL;
 875        }
 876
 877        list = paint_down_to_common(one, n, twos);
 878
 879        while (list) {
 880                struct commit_list *next = list->next;
 881                if (!(list->item->object.flags & STALE))
 882                        commit_list_insert_by_date(list->item, &result);
 883                free(list);
 884                list = next;
 885        }
 886        return result;
 887}
 888
 889struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 890{
 891        struct commit_list *i, *j, *k, *ret = NULL;
 892
 893        if (!in)
 894                return ret;
 895
 896        commit_list_insert(in->item, &ret);
 897
 898        for (i = in->next; i; i = i->next) {
 899                struct commit_list *new = NULL, *end = NULL;
 900
 901                for (j = ret; j; j = j->next) {
 902                        struct commit_list *bases;
 903                        bases = get_merge_bases(i->item, j->item, 1);
 904                        if (!new)
 905                                new = bases;
 906                        else
 907                                end->next = bases;
 908                        for (k = bases; k; k = k->next)
 909                                end = k;
 910                }
 911                ret = new;
 912        }
 913        return ret;
 914}
 915
 916static int remove_redundant(struct commit **array, int cnt)
 917{
 918        /*
 919         * Some commit in the array may be an ancestor of
 920         * another commit.  Move such commit to the end of
 921         * the array, and return the number of commits that
 922         * are independent from each other.
 923         */
 924        struct commit **work;
 925        unsigned char *redundant;
 926        int *filled_index;
 927        int i, j, filled;
 928
 929        work = xcalloc(cnt, sizeof(*work));
 930        redundant = xcalloc(cnt, 1);
 931        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 932
 933        for (i = 0; i < cnt; i++)
 934                parse_commit(array[i]);
 935        for (i = 0; i < cnt; i++) {
 936                struct commit_list *common;
 937
 938                if (redundant[i])
 939                        continue;
 940                for (j = filled = 0; j < cnt; j++) {
 941                        if (i == j || redundant[j])
 942                                continue;
 943                        filled_index[filled] = j;
 944                        work[filled++] = array[j];
 945                }
 946                common = paint_down_to_common(array[i], filled, work);
 947                if (array[i]->object.flags & PARENT2)
 948                        redundant[i] = 1;
 949                for (j = 0; j < filled; j++)
 950                        if (work[j]->object.flags & PARENT1)
 951                                redundant[filled_index[j]] = 1;
 952                clear_commit_marks(array[i], all_flags);
 953                for (j = 0; j < filled; j++)
 954                        clear_commit_marks(work[j], all_flags);
 955                free_commit_list(common);
 956        }
 957
 958        /* Now collect the result */
 959        memcpy(work, array, sizeof(*array) * cnt);
 960        for (i = filled = 0; i < cnt; i++)
 961                if (!redundant[i])
 962                        array[filled++] = work[i];
 963        for (j = filled, i = 0; i < cnt; i++)
 964                if (redundant[i])
 965                        array[j++] = work[i];
 966        free(work);
 967        free(redundant);
 968        free(filled_index);
 969        return filled;
 970}
 971
 972struct commit_list *get_merge_bases_many(struct commit *one,
 973                                         int n,
 974                                         struct commit **twos,
 975                                         int cleanup)
 976{
 977        struct commit_list *list;
 978        struct commit **rslt;
 979        struct commit_list *result;
 980        int cnt, i;
 981
 982        result = merge_bases_many(one, n, twos);
 983        for (i = 0; i < n; i++) {
 984                if (one == twos[i])
 985                        return result;
 986        }
 987        if (!result || !result->next) {
 988                if (cleanup) {
 989                        clear_commit_marks(one, all_flags);
 990                        clear_commit_marks_many(n, twos, all_flags);
 991                }
 992                return result;
 993        }
 994
 995        /* There are more than one */
 996        cnt = 0;
 997        list = result;
 998        while (list) {
 999                list = list->next;
1000                cnt++;
1001        }
1002        rslt = xcalloc(cnt, sizeof(*rslt));
1003        for (list = result, i = 0; list; list = list->next)
1004                rslt[i++] = list->item;
1005        free_commit_list(result);
1006
1007        clear_commit_marks(one, all_flags);
1008        clear_commit_marks_many(n, twos, all_flags);
1009
1010        cnt = remove_redundant(rslt, cnt);
1011        result = NULL;
1012        for (i = 0; i < cnt; i++)
1013                commit_list_insert_by_date(rslt[i], &result);
1014        free(rslt);
1015        return result;
1016}
1017
1018struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
1019                                    int cleanup)
1020{
1021        return get_merge_bases_many(one, 1, &two, cleanup);
1022}
1023
1024/*
1025 * Is "commit" a descendant of one of the elements on the "with_commit" list?
1026 */
1027int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1028{
1029        if (!with_commit)
1030                return 1;
1031        while (with_commit) {
1032                struct commit *other;
1033
1034                other = with_commit->item;
1035                with_commit = with_commit->next;
1036                if (in_merge_bases(other, commit))
1037                        return 1;
1038        }
1039        return 0;
1040}
1041
1042/*
1043 * Is "commit" an ancestor of one of the "references"?
1044 */
1045int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1046{
1047        struct commit_list *bases;
1048        int ret = 0, i;
1049
1050        if (parse_commit(commit))
1051                return ret;
1052        for (i = 0; i < nr_reference; i++)
1053                if (parse_commit(reference[i]))
1054                        return ret;
1055
1056        bases = paint_down_to_common(commit, nr_reference, reference);
1057        if (commit->object.flags & PARENT2)
1058                ret = 1;
1059        clear_commit_marks(commit, all_flags);
1060        clear_commit_marks_many(nr_reference, reference, all_flags);
1061        free_commit_list(bases);
1062        return ret;
1063}
1064
1065/*
1066 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1067 */
1068int in_merge_bases(struct commit *commit, struct commit *reference)
1069{
1070        return in_merge_bases_many(commit, 1, &reference);
1071}
1072
1073struct commit_list *reduce_heads(struct commit_list *heads)
1074{
1075        struct commit_list *p;
1076        struct commit_list *result = NULL, **tail = &result;
1077        struct commit **array;
1078        int num_head, i;
1079
1080        if (!heads)
1081                return NULL;
1082
1083        /* Uniquify */
1084        for (p = heads; p; p = p->next)
1085                p->item->object.flags &= ~STALE;
1086        for (p = heads, num_head = 0; p; p = p->next) {
1087                if (p->item->object.flags & STALE)
1088                        continue;
1089                p->item->object.flags |= STALE;
1090                num_head++;
1091        }
1092        array = xcalloc(sizeof(*array), num_head);
1093        for (p = heads, i = 0; p; p = p->next) {
1094                if (p->item->object.flags & STALE) {
1095                        array[i++] = p->item;
1096                        p->item->object.flags &= ~STALE;
1097                }
1098        }
1099        num_head = remove_redundant(array, num_head);
1100        for (i = 0; i < num_head; i++)
1101                tail = &commit_list_insert(array[i], tail)->next;
1102        return result;
1103}
1104
1105static const char gpg_sig_header[] = "gpgsig";
1106static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1107
1108static int do_sign_commit(struct strbuf *buf, const char *keyid)
1109{
1110        struct strbuf sig = STRBUF_INIT;
1111        int inspos, copypos;
1112
1113        /* find the end of the header */
1114        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1115
1116        if (!keyid || !*keyid)
1117                keyid = get_signing_key();
1118        if (sign_buffer(buf, &sig, keyid)) {
1119                strbuf_release(&sig);
1120                return -1;
1121        }
1122
1123        for (copypos = 0; sig.buf[copypos]; ) {
1124                const char *bol = sig.buf + copypos;
1125                const char *eol = strchrnul(bol, '\n');
1126                int len = (eol - bol) + !!*eol;
1127
1128                if (!copypos) {
1129                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1130                        inspos += gpg_sig_header_len;
1131                }
1132                strbuf_insert(buf, inspos++, " ", 1);
1133                strbuf_insert(buf, inspos, bol, len);
1134                inspos += len;
1135                copypos += len;
1136        }
1137        strbuf_release(&sig);
1138        return 0;
1139}
1140
1141int parse_signed_commit(const struct commit *commit,
1142                        struct strbuf *payload, struct strbuf *signature)
1143{
1144
1145        unsigned long size;
1146        const char *buffer = get_commit_buffer(commit, &size);
1147        int in_signature, saw_signature = -1;
1148        const char *line, *tail;
1149
1150        line = buffer;
1151        tail = buffer + size;
1152        in_signature = 0;
1153        saw_signature = 0;
1154        while (line < tail) {
1155                const char *sig = NULL;
1156                const char *next = memchr(line, '\n', tail - line);
1157
1158                next = next ? next + 1 : tail;
1159                if (in_signature && line[0] == ' ')
1160                        sig = line + 1;
1161                else if (starts_with(line, gpg_sig_header) &&
1162                         line[gpg_sig_header_len] == ' ')
1163                        sig = line + gpg_sig_header_len + 1;
1164                if (sig) {
1165                        strbuf_add(signature, sig, next - sig);
1166                        saw_signature = 1;
1167                        in_signature = 1;
1168                } else {
1169                        if (*line == '\n')
1170                                /* dump the whole remainder of the buffer */
1171                                next = tail;
1172                        strbuf_add(payload, line, next - line);
1173                        in_signature = 0;
1174                }
1175                line = next;
1176        }
1177        unuse_commit_buffer(commit, buffer);
1178        return saw_signature;
1179}
1180
1181static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1182{
1183        struct merge_remote_desc *desc;
1184        struct commit_extra_header *mergetag;
1185        char *buf;
1186        unsigned long size, len;
1187        enum object_type type;
1188
1189        desc = merge_remote_util(parent);
1190        if (!desc || !desc->obj)
1191                return;
1192        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1193        if (!buf || type != OBJ_TAG)
1194                goto free_return;
1195        len = parse_signature(buf, size);
1196        if (size == len)
1197                goto free_return;
1198        /*
1199         * We could verify this signature and either omit the tag when
1200         * it does not validate, but the integrator may not have the
1201         * public key of the signer of the tag he is merging, while a
1202         * later auditor may have it while auditing, so let's not run
1203         * verify-signed-buffer here for now...
1204         *
1205         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1206         *      warn("warning: signed tag unverified.");
1207         */
1208        mergetag = xcalloc(1, sizeof(*mergetag));
1209        mergetag->key = xstrdup("mergetag");
1210        mergetag->value = buf;
1211        mergetag->len = size;
1212
1213        **tail = mergetag;
1214        *tail = &mergetag->next;
1215        return;
1216
1217free_return:
1218        free(buf);
1219}
1220
1221static struct {
1222        char result;
1223        const char *check;
1224} sigcheck_gpg_status[] = {
1225        { 'G', "\n[GNUPG:] GOODSIG " },
1226        { 'B', "\n[GNUPG:] BADSIG " },
1227        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1228        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1229};
1230
1231static void parse_gpg_output(struct signature_check *sigc)
1232{
1233        const char *buf = sigc->gpg_status;
1234        int i;
1235
1236        /* Iterate over all search strings */
1237        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1238                const char *found, *next;
1239
1240                found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
1241                if (!found) {
1242                        found = strstr(buf, sigcheck_gpg_status[i].check);
1243                        if (!found)
1244                                continue;
1245                        found += strlen(sigcheck_gpg_status[i].check);
1246                }
1247                sigc->result = sigcheck_gpg_status[i].result;
1248                /* The trust messages are not followed by key/signer information */
1249                if (sigc->result != 'U') {
1250                        sigc->key = xmemdupz(found, 16);
1251                        found += 17;
1252                        next = strchrnul(found, '\n');
1253                        sigc->signer = xmemdupz(found, next - found);
1254                }
1255        }
1256}
1257
1258void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1259{
1260        struct strbuf payload = STRBUF_INIT;
1261        struct strbuf signature = STRBUF_INIT;
1262        struct strbuf gpg_output = STRBUF_INIT;
1263        struct strbuf gpg_status = STRBUF_INIT;
1264        int status;
1265
1266        sigc->result = 'N';
1267
1268        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1269                goto out;
1270        status = verify_signed_buffer(payload.buf, payload.len,
1271                                      signature.buf, signature.len,
1272                                      &gpg_output, &gpg_status);
1273        if (status && !gpg_output.len)
1274                goto out;
1275        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1276        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1277        parse_gpg_output(sigc);
1278
1279 out:
1280        strbuf_release(&gpg_status);
1281        strbuf_release(&gpg_output);
1282        strbuf_release(&payload);
1283        strbuf_release(&signature);
1284}
1285
1286
1287
1288void append_merge_tag_headers(struct commit_list *parents,
1289                              struct commit_extra_header ***tail)
1290{
1291        while (parents) {
1292                struct commit *parent = parents->item;
1293                handle_signed_tag(parent, tail);
1294                parents = parents->next;
1295        }
1296}
1297
1298static void add_extra_header(struct strbuf *buffer,
1299                             struct commit_extra_header *extra)
1300{
1301        strbuf_addstr(buffer, extra->key);
1302        if (extra->len)
1303                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1304        else
1305                strbuf_addch(buffer, '\n');
1306}
1307
1308struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1309                                                      const char **exclude)
1310{
1311        struct commit_extra_header *extra = NULL;
1312        unsigned long size;
1313        const char *buffer = get_commit_buffer(commit, &size);
1314        extra = read_commit_extra_header_lines(buffer, size, exclude);
1315        unuse_commit_buffer(commit, buffer);
1316        return extra;
1317}
1318
1319static inline int standard_header_field(const char *field, size_t len)
1320{
1321        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1322                (len == 6 && !memcmp(field, "parent ", 7)) ||
1323                (len == 6 && !memcmp(field, "author ", 7)) ||
1324                (len == 9 && !memcmp(field, "committer ", 10)) ||
1325                (len == 8 && !memcmp(field, "encoding ", 9)));
1326}
1327
1328static int excluded_header_field(const char *field, size_t len, const char **exclude)
1329{
1330        if (!exclude)
1331                return 0;
1332
1333        while (*exclude) {
1334                size_t xlen = strlen(*exclude);
1335                if (len == xlen &&
1336                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1337                        return 1;
1338                exclude++;
1339        }
1340        return 0;
1341}
1342
1343static struct commit_extra_header *read_commit_extra_header_lines(
1344        const char *buffer, size_t size,
1345        const char **exclude)
1346{
1347        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1348        const char *line, *next, *eof, *eob;
1349        struct strbuf buf = STRBUF_INIT;
1350
1351        for (line = buffer, eob = line + size;
1352             line < eob && *line != '\n';
1353             line = next) {
1354                next = memchr(line, '\n', eob - line);
1355                next = next ? next + 1 : eob;
1356                if (*line == ' ') {
1357                        /* continuation */
1358                        if (it)
1359                                strbuf_add(&buf, line + 1, next - (line + 1));
1360                        continue;
1361                }
1362                if (it)
1363                        it->value = strbuf_detach(&buf, &it->len);
1364                strbuf_reset(&buf);
1365                it = NULL;
1366
1367                eof = strchr(line, ' ');
1368                if (next <= eof)
1369                        eof = next;
1370
1371                if (standard_header_field(line, eof - line) ||
1372                    excluded_header_field(line, eof - line, exclude))
1373                        continue;
1374
1375                it = xcalloc(1, sizeof(*it));
1376                it->key = xmemdupz(line, eof-line);
1377                *tail = it;
1378                tail = &it->next;
1379                if (eof + 1 < next)
1380                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1381        }
1382        if (it)
1383                it->value = strbuf_detach(&buf, &it->len);
1384        return extra;
1385}
1386
1387void free_commit_extra_headers(struct commit_extra_header *extra)
1388{
1389        while (extra) {
1390                struct commit_extra_header *next = extra->next;
1391                free(extra->key);
1392                free(extra->value);
1393                free(extra);
1394                extra = next;
1395        }
1396}
1397
1398int commit_tree(const char *msg, size_t msg_len,
1399                const unsigned char *tree,
1400                struct commit_list *parents, unsigned char *ret,
1401                const char *author, const char *sign_commit)
1402{
1403        struct commit_extra_header *extra = NULL, **tail = &extra;
1404        int result;
1405
1406        append_merge_tag_headers(parents, &tail);
1407        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1408                                      author, sign_commit, extra);
1409        free_commit_extra_headers(extra);
1410        return result;
1411}
1412
1413static int find_invalid_utf8(const char *buf, int len)
1414{
1415        int offset = 0;
1416        static const unsigned int max_codepoint[] = {
1417                0x7f, 0x7ff, 0xffff, 0x10ffff
1418        };
1419
1420        while (len) {
1421                unsigned char c = *buf++;
1422                int bytes, bad_offset;
1423                unsigned int codepoint;
1424                unsigned int min_val, max_val;
1425
1426                len--;
1427                offset++;
1428
1429                /* Simple US-ASCII? No worries. */
1430                if (c < 0x80)
1431                        continue;
1432
1433                bad_offset = offset-1;
1434
1435                /*
1436                 * Count how many more high bits set: that's how
1437                 * many more bytes this sequence should have.
1438                 */
1439                bytes = 0;
1440                while (c & 0x40) {
1441                        c <<= 1;
1442                        bytes++;
1443                }
1444
1445                /*
1446                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1447                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1448                 */
1449                if (bytes < 1 || 3 < bytes)
1450                        return bad_offset;
1451
1452                /* Do we *have* that many bytes? */
1453                if (len < bytes)
1454                        return bad_offset;
1455
1456                /*
1457                 * Place the encoded bits at the bottom of the value and compute the
1458                 * valid range.
1459                 */
1460                codepoint = (c & 0x7f) >> bytes;
1461                min_val = max_codepoint[bytes-1] + 1;
1462                max_val = max_codepoint[bytes];
1463
1464                offset += bytes;
1465                len -= bytes;
1466
1467                /* And verify that they are good continuation bytes */
1468                do {
1469                        codepoint <<= 6;
1470                        codepoint |= *buf & 0x3f;
1471                        if ((*buf++ & 0xc0) != 0x80)
1472                                return bad_offset;
1473                } while (--bytes);
1474
1475                /* Reject codepoints that are out of range for the sequence length. */
1476                if (codepoint < min_val || codepoint > max_val)
1477                        return bad_offset;
1478                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1479                if ((codepoint & 0x1ff800) == 0xd800)
1480                        return bad_offset;
1481                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1482                if ((codepoint & 0xfffe) == 0xfffe)
1483                        return bad_offset;
1484                /* So are anything in the range U+FDD0..U+FDEF. */
1485                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1486                        return bad_offset;
1487        }
1488        return -1;
1489}
1490
1491/*
1492 * This verifies that the buffer is in proper utf8 format.
1493 *
1494 * If it isn't, it assumes any non-utf8 characters are Latin1,
1495 * and does the conversion.
1496 */
1497static int verify_utf8(struct strbuf *buf)
1498{
1499        int ok = 1;
1500        long pos = 0;
1501
1502        for (;;) {
1503                int bad;
1504                unsigned char c;
1505                unsigned char replace[2];
1506
1507                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1508                if (bad < 0)
1509                        return ok;
1510                pos += bad;
1511                ok = 0;
1512                c = buf->buf[pos];
1513                strbuf_remove(buf, pos, 1);
1514
1515                /* We know 'c' must be in the range 128-255 */
1516                replace[0] = 0xc0 + (c >> 6);
1517                replace[1] = 0x80 + (c & 0x3f);
1518                strbuf_insert(buf, pos, replace, 2);
1519                pos += 2;
1520        }
1521}
1522
1523static const char commit_utf8_warn[] =
1524"Warning: commit message did not conform to UTF-8.\n"
1525"You may want to amend it after fixing the message, or set the config\n"
1526"variable i18n.commitencoding to the encoding your project uses.\n";
1527
1528int commit_tree_extended(const char *msg, size_t msg_len,
1529                         const unsigned char *tree,
1530                         struct commit_list *parents, unsigned char *ret,
1531                         const char *author, const char *sign_commit,
1532                         struct commit_extra_header *extra)
1533{
1534        int result;
1535        int encoding_is_utf8;
1536        struct strbuf buffer;
1537
1538        assert_sha1_type(tree, OBJ_TREE);
1539
1540        if (memchr(msg, '\0', msg_len))
1541                return error("a NUL byte in commit log message not allowed.");
1542
1543        /* Not having i18n.commitencoding is the same as having utf-8 */
1544        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1545
1546        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1547        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1548
1549        /*
1550         * NOTE! This ordering means that the same exact tree merged with a
1551         * different order of parents will be a _different_ changeset even
1552         * if everything else stays the same.
1553         */
1554        while (parents) {
1555                struct commit_list *next = parents->next;
1556                struct commit *parent = parents->item;
1557
1558                strbuf_addf(&buffer, "parent %s\n",
1559                            sha1_to_hex(parent->object.sha1));
1560                free(parents);
1561                parents = next;
1562        }
1563
1564        /* Person/date information */
1565        if (!author)
1566                author = git_author_info(IDENT_STRICT);
1567        strbuf_addf(&buffer, "author %s\n", author);
1568        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1569        if (!encoding_is_utf8)
1570                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1571
1572        while (extra) {
1573                add_extra_header(&buffer, extra);
1574                extra = extra->next;
1575        }
1576        strbuf_addch(&buffer, '\n');
1577
1578        /* And add the comment */
1579        strbuf_add(&buffer, msg, msg_len);
1580
1581        /* And check the encoding */
1582        if (encoding_is_utf8 && !verify_utf8(&buffer))
1583                fprintf(stderr, commit_utf8_warn);
1584
1585        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1586                return -1;
1587
1588        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1589        strbuf_release(&buffer);
1590        return result;
1591}
1592
1593struct commit *get_merge_parent(const char *name)
1594{
1595        struct object *obj;
1596        struct commit *commit;
1597        unsigned char sha1[20];
1598        if (get_sha1(name, sha1))
1599                return NULL;
1600        obj = parse_object(sha1);
1601        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1602        if (commit && !commit->util) {
1603                struct merge_remote_desc *desc;
1604                desc = xmalloc(sizeof(*desc));
1605                desc->obj = obj;
1606                desc->name = strdup(name);
1607                commit->util = desc;
1608        }
1609        return commit;
1610}
1611
1612/*
1613 * Append a commit to the end of the commit_list.
1614 *
1615 * next starts by pointing to the variable that holds the head of an
1616 * empty commit_list, and is updated to point to the "next" field of
1617 * the last item on the list as new commits are appended.
1618 *
1619 * Usage example:
1620 *
1621 *     struct commit_list *list;
1622 *     struct commit_list **next = &list;
1623 *
1624 *     next = commit_list_append(c1, next);
1625 *     next = commit_list_append(c2, next);
1626 *     assert(commit_list_count(list) == 2);
1627 *     return list;
1628 */
1629struct commit_list **commit_list_append(struct commit *commit,
1630                                        struct commit_list **next)
1631{
1632        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1633        new->item = commit;
1634        *next = new;
1635        new->next = NULL;
1636        return &new->next;
1637}
1638
1639void print_commit_list(struct commit_list *list,
1640                       const char *format_cur,
1641                       const char *format_last)
1642{
1643        for ( ; list; list = list->next) {
1644                const char *format = list->next ? format_cur : format_last;
1645                printf(format, sha1_to_hex(list->item->object.sha1));
1646        }
1647}