Andrew's git / gitweb.git / commit.c
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commit.con commit Merge branch 'rs/empty-archive' into maint (167843f)
   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
  12static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  13
  14int save_commit_buffer = 1;
  15
  16const char *commit_type = "commit";
  17
  18static struct commit *check_commit(struct object *obj,
  19                                   const unsigned char *sha1,
  20                                   int quiet)
  21{
  22        if (obj->type != OBJ_COMMIT) {
  23                if (!quiet)
  24                        error("Object %s is a %s, not a commit",
  25                              sha1_to_hex(sha1), typename(obj->type));
  26                return NULL;
  27        }
  28        return (struct commit *) obj;
  29}
  30
  31struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  32                                              int quiet)
  33{
  34        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  35
  36        if (!obj)
  37                return NULL;
  38        return check_commit(obj, sha1, quiet);
  39}
  40
  41struct commit *lookup_commit_reference(const unsigned char *sha1)
  42{
  43        return lookup_commit_reference_gently(sha1, 0);
  44}
  45
  46struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  47{
  48        struct commit *c = lookup_commit_reference(sha1);
  49        if (!c)
  50                die(_("could not parse %s"), ref_name);
  51        if (hashcmp(sha1, c->object.sha1)) {
  52                warning(_("%s %s is not a commit!"),
  53                        ref_name, sha1_to_hex(sha1));
  54        }
  55        return c;
  56}
  57
  58struct commit *lookup_commit(const unsigned char *sha1)
  59{
  60        struct object *obj = lookup_object(sha1);
  61        if (!obj)
  62                return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  63        if (!obj->type)
  64                obj->type = OBJ_COMMIT;
  65        return check_commit(obj, sha1, 0);
  66}
  67
  68struct commit *lookup_commit_reference_by_name(const char *name)
  69{
  70        unsigned char sha1[20];
  71        struct commit *commit;
  72
  73        if (get_sha1_committish(name, sha1))
  74                return NULL;
  75        commit = lookup_commit_reference(sha1);
  76        if (!commit || parse_commit(commit))
  77                return NULL;
  78        return commit;
  79}
  80
  81static unsigned long parse_commit_date(const char *buf, const char *tail)
  82{
  83        const char *dateptr;
  84
  85        if (buf + 6 >= tail)
  86                return 0;
  87        if (memcmp(buf, "author", 6))
  88                return 0;
  89        while (buf < tail && *buf++ != '\n')
  90                /* nada */;
  91        if (buf + 9 >= tail)
  92                return 0;
  93        if (memcmp(buf, "committer", 9))
  94                return 0;
  95        while (buf < tail && *buf++ != '>')
  96                /* nada */;
  97        if (buf >= tail)
  98                return 0;
  99        dateptr = buf;
 100        while (buf < tail && *buf++ != '\n')
 101                /* nada */;
 102        if (buf >= tail)
 103                return 0;
 104        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 105        return strtoul(dateptr, NULL, 10);
 106}
 107
 108static struct commit_graft **commit_graft;
 109static int commit_graft_alloc, commit_graft_nr;
 110
 111static int commit_graft_pos(const unsigned char *sha1)
 112{
 113        int lo, hi;
 114        lo = 0;
 115        hi = commit_graft_nr;
 116        while (lo < hi) {
 117                int mi = (lo + hi) / 2;
 118                struct commit_graft *graft = commit_graft[mi];
 119                int cmp = hashcmp(sha1, graft->sha1);
 120                if (!cmp)
 121                        return mi;
 122                if (cmp < 0)
 123                        hi = mi;
 124                else
 125                        lo = mi + 1;
 126        }
 127        return -lo - 1;
 128}
 129
 130int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 131{
 132        int pos = commit_graft_pos(graft->sha1);
 133
 134        if (0 <= pos) {
 135                if (ignore_dups)
 136                        free(graft);
 137                else {
 138                        free(commit_graft[pos]);
 139                        commit_graft[pos] = graft;
 140                }
 141                return 1;
 142        }
 143        pos = -pos - 1;
 144        if (commit_graft_alloc <= ++commit_graft_nr) {
 145                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 146                commit_graft = xrealloc(commit_graft,
 147                                        sizeof(*commit_graft) *
 148                                        commit_graft_alloc);
 149        }
 150        if (pos < commit_graft_nr)
 151                memmove(commit_graft + pos + 1,
 152                        commit_graft + pos,
 153                        (commit_graft_nr - pos - 1) *
 154                        sizeof(*commit_graft));
 155        commit_graft[pos] = graft;
 156        return 0;
 157}
 158
 159struct commit_graft *read_graft_line(char *buf, int len)
 160{
 161        /* The format is just "Commit Parent1 Parent2 ...\n" */
 162        int i;
 163        struct commit_graft *graft = NULL;
 164
 165        while (len && isspace(buf[len-1]))
 166                buf[--len] = '\0';
 167        if (buf[0] == '#' || buf[0] == '\0')
 168                return NULL;
 169        if ((len + 1) % 41)
 170                goto bad_graft_data;
 171        i = (len + 1) / 41 - 1;
 172        graft = xmalloc(sizeof(*graft) + 20 * i);
 173        graft->nr_parent = i;
 174        if (get_sha1_hex(buf, graft->sha1))
 175                goto bad_graft_data;
 176        for (i = 40; i < len; i += 41) {
 177                if (buf[i] != ' ')
 178                        goto bad_graft_data;
 179                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 180                        goto bad_graft_data;
 181        }
 182        return graft;
 183
 184bad_graft_data:
 185        error("bad graft data: %s", buf);
 186        free(graft);
 187        return NULL;
 188}
 189
 190static int read_graft_file(const char *graft_file)
 191{
 192        FILE *fp = fopen(graft_file, "r");
 193        char buf[1024];
 194        if (!fp)
 195                return -1;
 196        while (fgets(buf, sizeof(buf), fp)) {
 197                /* The format is just "Commit Parent1 Parent2 ...\n" */
 198                int len = strlen(buf);
 199                struct commit_graft *graft = read_graft_line(buf, len);
 200                if (!graft)
 201                        continue;
 202                if (register_commit_graft(graft, 1))
 203                        error("duplicate graft data: %s", buf);
 204        }
 205        fclose(fp);
 206        return 0;
 207}
 208
 209static void prepare_commit_graft(void)
 210{
 211        static int commit_graft_prepared;
 212        char *graft_file;
 213
 214        if (commit_graft_prepared)
 215                return;
 216        graft_file = get_graft_file();
 217        read_graft_file(graft_file);
 218        /* make sure shallows are read */
 219        is_repository_shallow();
 220        commit_graft_prepared = 1;
 221}
 222
 223struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 224{
 225        int pos;
 226        prepare_commit_graft();
 227        pos = commit_graft_pos(sha1);
 228        if (pos < 0)
 229                return NULL;
 230        return commit_graft[pos];
 231}
 232
 233int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 234{
 235        int i, ret;
 236        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 237                ret = fn(commit_graft[i], cb_data);
 238        return ret;
 239}
 240
 241int unregister_shallow(const unsigned char *sha1)
 242{
 243        int pos = commit_graft_pos(sha1);
 244        if (pos < 0)
 245                return -1;
 246        if (pos + 1 < commit_graft_nr)
 247                memmove(commit_graft + pos, commit_graft + pos + 1,
 248                                sizeof(struct commit_graft *)
 249                                * (commit_graft_nr - pos - 1));
 250        commit_graft_nr--;
 251        return 0;
 252}
 253
 254int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 255{
 256        const char *tail = buffer;
 257        const char *bufptr = buffer;
 258        unsigned char parent[20];
 259        struct commit_list **pptr;
 260        struct commit_graft *graft;
 261
 262        if (item->object.parsed)
 263                return 0;
 264        item->object.parsed = 1;
 265        tail += size;
 266        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 267                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 268        if (get_sha1_hex(bufptr + 5, parent) < 0)
 269                return error("bad tree pointer in commit %s",
 270                             sha1_to_hex(item->object.sha1));
 271        item->tree = lookup_tree(parent);
 272        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 273        pptr = &item->parents;
 274
 275        graft = lookup_commit_graft(item->object.sha1);
 276        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 277                struct commit *new_parent;
 278
 279                if (tail <= bufptr + 48 ||
 280                    get_sha1_hex(bufptr + 7, parent) ||
 281                    bufptr[47] != '\n')
 282                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 283                bufptr += 48;
 284                /*
 285                 * The clone is shallow if nr_parent < 0, and we must
 286                 * not traverse its real parents even when we unhide them.
 287                 */
 288                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 289                        continue;
 290                new_parent = lookup_commit(parent);
 291                if (new_parent)
 292                        pptr = &commit_list_insert(new_parent, pptr)->next;
 293        }
 294        if (graft) {
 295                int i;
 296                struct commit *new_parent;
 297                for (i = 0; i < graft->nr_parent; i++) {
 298                        new_parent = lookup_commit(graft->parent[i]);
 299                        if (!new_parent)
 300                                continue;
 301                        pptr = &commit_list_insert(new_parent, pptr)->next;
 302                }
 303        }
 304        item->date = parse_commit_date(bufptr, tail);
 305
 306        return 0;
 307}
 308
 309int parse_commit(struct commit *item)
 310{
 311        enum object_type type;
 312        void *buffer;
 313        unsigned long size;
 314        int ret;
 315
 316        if (!item)
 317                return -1;
 318        if (item->object.parsed)
 319                return 0;
 320        buffer = read_sha1_file(item->object.sha1, &type, &size);
 321        if (!buffer)
 322                return error("Could not read %s",
 323                             sha1_to_hex(item->object.sha1));
 324        if (type != OBJ_COMMIT) {
 325                free(buffer);
 326                return error("Object %s not a commit",
 327                             sha1_to_hex(item->object.sha1));
 328        }
 329        ret = parse_commit_buffer(item, buffer, size);
 330        if (save_commit_buffer && !ret) {
 331                item->buffer = buffer;
 332                return 0;
 333        }
 334        free(buffer);
 335        return ret;
 336}
 337
 338int find_commit_subject(const char *commit_buffer, const char **subject)
 339{
 340        const char *eol;
 341        const char *p = commit_buffer;
 342
 343        while (*p && (*p != '\n' || p[1] != '\n'))
 344                p++;
 345        if (*p) {
 346                p += 2;
 347                for (eol = p; *eol && *eol != '\n'; eol++)
 348                        ; /* do nothing */
 349        } else
 350                eol = p;
 351
 352        *subject = p;
 353
 354        return eol - p;
 355}
 356
 357struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 358{
 359        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 360        new_list->item = item;
 361        new_list->next = *list_p;
 362        *list_p = new_list;
 363        return new_list;
 364}
 365
 366unsigned commit_list_count(const struct commit_list *l)
 367{
 368        unsigned c = 0;
 369        for (; l; l = l->next )
 370                c++;
 371        return c;
 372}
 373
 374void free_commit_list(struct commit_list *list)
 375{
 376        while (list) {
 377                struct commit_list *temp = list;
 378                list = temp->next;
 379                free(temp);
 380        }
 381}
 382
 383struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 384{
 385        struct commit_list **pp = list;
 386        struct commit_list *p;
 387        while ((p = *pp) != NULL) {
 388                if (p->item->date < item->date) {
 389                        break;
 390                }
 391                pp = &p->next;
 392        }
 393        return commit_list_insert(item, pp);
 394}
 395
 396static int commit_list_compare_by_date(const void *a, const void *b)
 397{
 398        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 399        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 400        if (a_date < b_date)
 401                return 1;
 402        if (a_date > b_date)
 403                return -1;
 404        return 0;
 405}
 406
 407static void *commit_list_get_next(const void *a)
 408{
 409        return ((const struct commit_list *)a)->next;
 410}
 411
 412static void commit_list_set_next(void *a, void *next)
 413{
 414        ((struct commit_list *)a)->next = next;
 415}
 416
 417void commit_list_sort_by_date(struct commit_list **list)
 418{
 419        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 420                                commit_list_compare_by_date);
 421}
 422
 423struct commit *pop_most_recent_commit(struct commit_list **list,
 424                                      unsigned int mark)
 425{
 426        struct commit *ret = (*list)->item;
 427        struct commit_list *parents = ret->parents;
 428        struct commit_list *old = *list;
 429
 430        *list = (*list)->next;
 431        free(old);
 432
 433        while (parents) {
 434                struct commit *commit = parents->item;
 435                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 436                        commit->object.flags |= mark;
 437                        commit_list_insert_by_date(commit, list);
 438                }
 439                parents = parents->next;
 440        }
 441        return ret;
 442}
 443
 444static void clear_commit_marks_1(struct commit_list **plist,
 445                                 struct commit *commit, unsigned int mark)
 446{
 447        while (commit) {
 448                struct commit_list *parents;
 449
 450                if (!(mark & commit->object.flags))
 451                        return;
 452
 453                commit->object.flags &= ~mark;
 454
 455                parents = commit->parents;
 456                if (!parents)
 457                        return;
 458
 459                while ((parents = parents->next))
 460                        commit_list_insert(parents->item, plist);
 461
 462                commit = commit->parents->item;
 463        }
 464}
 465
 466void clear_commit_marks(struct commit *commit, unsigned int mark)
 467{
 468        struct commit_list *list = NULL;
 469        commit_list_insert(commit, &list);
 470        while (list)
 471                clear_commit_marks_1(&list, pop_commit(&list), mark);
 472}
 473
 474void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 475{
 476        struct object *object;
 477        struct commit *commit;
 478        unsigned int i;
 479
 480        for (i = 0; i < a->nr; i++) {
 481                object = a->objects[i].item;
 482                commit = lookup_commit_reference_gently(object->sha1, 1);
 483                if (commit)
 484                        clear_commit_marks(commit, mark);
 485        }
 486}
 487
 488struct commit *pop_commit(struct commit_list **stack)
 489{
 490        struct commit_list *top = *stack;
 491        struct commit *item = top ? top->item : NULL;
 492
 493        if (top) {
 494                *stack = top->next;
 495                free(top);
 496        }
 497        return item;
 498}
 499
 500/*
 501 * Performs an in-place topological sort on the list supplied.
 502 */
 503void sort_in_topological_order(struct commit_list ** list, int lifo)
 504{
 505        struct commit_list *next, *orig = *list;
 506        struct commit_list *work, **insert;
 507        struct commit_list **pptr;
 508
 509        if (!orig)
 510                return;
 511        *list = NULL;
 512
 513        /* Mark them and clear the indegree */
 514        for (next = orig; next; next = next->next) {
 515                struct commit *commit = next->item;
 516                commit->indegree = 1;
 517        }
 518
 519        /* update the indegree */
 520        for (next = orig; next; next = next->next) {
 521                struct commit_list * parents = next->item->parents;
 522                while (parents) {
 523                        struct commit *parent = parents->item;
 524
 525                        if (parent->indegree)
 526                                parent->indegree++;
 527                        parents = parents->next;
 528                }
 529        }
 530
 531        /*
 532         * find the tips
 533         *
 534         * tips are nodes not reachable from any other node in the list
 535         *
 536         * the tips serve as a starting set for the work queue.
 537         */
 538        work = NULL;
 539        insert = &work;
 540        for (next = orig; next; next = next->next) {
 541                struct commit *commit = next->item;
 542
 543                if (commit->indegree == 1)
 544                        insert = &commit_list_insert(commit, insert)->next;
 545        }
 546
 547        /* process the list in topological order */
 548        if (!lifo)
 549                commit_list_sort_by_date(&work);
 550
 551        pptr = list;
 552        *list = NULL;
 553        while (work) {
 554                struct commit *commit;
 555                struct commit_list *parents, *work_item;
 556
 557                work_item = work;
 558                work = work_item->next;
 559                work_item->next = NULL;
 560
 561                commit = work_item->item;
 562                for (parents = commit->parents; parents ; parents = parents->next) {
 563                        struct commit *parent = parents->item;
 564
 565                        if (!parent->indegree)
 566                                continue;
 567
 568                        /*
 569                         * parents are only enqueued for emission
 570                         * when all their children have been emitted thereby
 571                         * guaranteeing topological order.
 572                         */
 573                        if (--parent->indegree == 1) {
 574                                if (!lifo)
 575                                        commit_list_insert_by_date(parent, &work);
 576                                else
 577                                        commit_list_insert(parent, &work);
 578                        }
 579                }
 580                /*
 581                 * work_item is a commit all of whose children
 582                 * have already been emitted. we can emit it now.
 583                 */
 584                commit->indegree = 0;
 585                *pptr = work_item;
 586                pptr = &work_item->next;
 587        }
 588}
 589
 590/* merge-base stuff */
 591
 592/* bits #0..15 in revision.h */
 593#define PARENT1         (1u<<16)
 594#define PARENT2         (1u<<17)
 595#define STALE           (1u<<18)
 596#define RESULT          (1u<<19)
 597
 598static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 599
 600static struct commit *interesting(struct commit_list *list)
 601{
 602        while (list) {
 603                struct commit *commit = list->item;
 604                list = list->next;
 605                if (commit->object.flags & STALE)
 606                        continue;
 607                return commit;
 608        }
 609        return NULL;
 610}
 611
 612/* all input commits in one and twos[] must have been parsed! */
 613static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 614{
 615        struct commit_list *list = NULL;
 616        struct commit_list *result = NULL;
 617        int i;
 618
 619        one->object.flags |= PARENT1;
 620        commit_list_insert_by_date(one, &list);
 621        if (!n)
 622                return list;
 623        for (i = 0; i < n; i++) {
 624                twos[i]->object.flags |= PARENT2;
 625                commit_list_insert_by_date(twos[i], &list);
 626        }
 627
 628        while (interesting(list)) {
 629                struct commit *commit;
 630                struct commit_list *parents;
 631                struct commit_list *next;
 632                int flags;
 633
 634                commit = list->item;
 635                next = list->next;
 636                free(list);
 637                list = next;
 638
 639                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 640                if (flags == (PARENT1 | PARENT2)) {
 641                        if (!(commit->object.flags & RESULT)) {
 642                                commit->object.flags |= RESULT;
 643                                commit_list_insert_by_date(commit, &result);
 644                        }
 645                        /* Mark parents of a found merge stale */
 646                        flags |= STALE;
 647                }
 648                parents = commit->parents;
 649                while (parents) {
 650                        struct commit *p = parents->item;
 651                        parents = parents->next;
 652                        if ((p->object.flags & flags) == flags)
 653                                continue;
 654                        if (parse_commit(p))
 655                                return NULL;
 656                        p->object.flags |= flags;
 657                        commit_list_insert_by_date(p, &list);
 658                }
 659        }
 660
 661        free_commit_list(list);
 662        return result;
 663}
 664
 665static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 666{
 667        struct commit_list *list = NULL;
 668        struct commit_list *result = NULL;
 669        int i;
 670
 671        for (i = 0; i < n; i++) {
 672                if (one == twos[i])
 673                        /*
 674                         * We do not mark this even with RESULT so we do not
 675                         * have to clean it up.
 676                         */
 677                        return commit_list_insert(one, &result);
 678        }
 679
 680        if (parse_commit(one))
 681                return NULL;
 682        for (i = 0; i < n; i++) {
 683                if (parse_commit(twos[i]))
 684                        return NULL;
 685        }
 686
 687        list = paint_down_to_common(one, n, twos);
 688
 689        while (list) {
 690                struct commit_list *next = list->next;
 691                if (!(list->item->object.flags & STALE))
 692                        commit_list_insert_by_date(list->item, &result);
 693                free(list);
 694                list = next;
 695        }
 696        return result;
 697}
 698
 699struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 700{
 701        struct commit_list *i, *j, *k, *ret = NULL;
 702        struct commit_list **pptr = &ret;
 703
 704        for (i = in; i; i = i->next) {
 705                if (!ret)
 706                        pptr = &commit_list_insert(i->item, pptr)->next;
 707                else {
 708                        struct commit_list *new = NULL, *end = NULL;
 709
 710                        for (j = ret; j; j = j->next) {
 711                                struct commit_list *bases;
 712                                bases = get_merge_bases(i->item, j->item, 1);
 713                                if (!new)
 714                                        new = bases;
 715                                else
 716                                        end->next = bases;
 717                                for (k = bases; k; k = k->next)
 718                                        end = k;
 719                        }
 720                        ret = new;
 721                }
 722        }
 723        return ret;
 724}
 725
 726static int remove_redundant(struct commit **array, int cnt)
 727{
 728        /*
 729         * Some commit in the array may be an ancestor of
 730         * another commit.  Move such commit to the end of
 731         * the array, and return the number of commits that
 732         * are independent from each other.
 733         */
 734        struct commit **work;
 735        unsigned char *redundant;
 736        int *filled_index;
 737        int i, j, filled;
 738
 739        work = xcalloc(cnt, sizeof(*work));
 740        redundant = xcalloc(cnt, 1);
 741        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 742
 743        for (i = 0; i < cnt; i++)
 744                parse_commit(array[i]);
 745        for (i = 0; i < cnt; i++) {
 746                struct commit_list *common;
 747
 748                if (redundant[i])
 749                        continue;
 750                for (j = filled = 0; j < cnt; j++) {
 751                        if (i == j || redundant[j])
 752                                continue;
 753                        filled_index[filled] = j;
 754                        work[filled++] = array[j];
 755                }
 756                common = paint_down_to_common(array[i], filled, work);
 757                if (array[i]->object.flags & PARENT2)
 758                        redundant[i] = 1;
 759                for (j = 0; j < filled; j++)
 760                        if (work[j]->object.flags & PARENT1)
 761                                redundant[filled_index[j]] = 1;
 762                clear_commit_marks(array[i], all_flags);
 763                for (j = 0; j < filled; j++)
 764                        clear_commit_marks(work[j], all_flags);
 765                free_commit_list(common);
 766        }
 767
 768        /* Now collect the result */
 769        memcpy(work, array, sizeof(*array) * cnt);
 770        for (i = filled = 0; i < cnt; i++)
 771                if (!redundant[i])
 772                        array[filled++] = work[i];
 773        for (j = filled, i = 0; i < cnt; i++)
 774                if (redundant[i])
 775                        array[j++] = work[i];
 776        free(work);
 777        free(redundant);
 778        free(filled_index);
 779        return filled;
 780}
 781
 782struct commit_list *get_merge_bases_many(struct commit *one,
 783                                         int n,
 784                                         struct commit **twos,
 785                                         int cleanup)
 786{
 787        struct commit_list *list;
 788        struct commit **rslt;
 789        struct commit_list *result;
 790        int cnt, i;
 791
 792        result = merge_bases_many(one, n, twos);
 793        for (i = 0; i < n; i++) {
 794                if (one == twos[i])
 795                        return result;
 796        }
 797        if (!result || !result->next) {
 798                if (cleanup) {
 799                        clear_commit_marks(one, all_flags);
 800                        for (i = 0; i < n; i++)
 801                                clear_commit_marks(twos[i], all_flags);
 802                }
 803                return result;
 804        }
 805
 806        /* There are more than one */
 807        cnt = 0;
 808        list = result;
 809        while (list) {
 810                list = list->next;
 811                cnt++;
 812        }
 813        rslt = xcalloc(cnt, sizeof(*rslt));
 814        for (list = result, i = 0; list; list = list->next)
 815                rslt[i++] = list->item;
 816        free_commit_list(result);
 817
 818        clear_commit_marks(one, all_flags);
 819        for (i = 0; i < n; i++)
 820                clear_commit_marks(twos[i], all_flags);
 821
 822        cnt = remove_redundant(rslt, cnt);
 823        result = NULL;
 824        for (i = 0; i < cnt; i++)
 825                commit_list_insert_by_date(rslt[i], &result);
 826        free(rslt);
 827        return result;
 828}
 829
 830struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 831                                    int cleanup)
 832{
 833        return get_merge_bases_many(one, 1, &two, cleanup);
 834}
 835
 836/*
 837 * Is "commit" a descendant of one of the elements on the "with_commit" list?
 838 */
 839int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 840{
 841        if (!with_commit)
 842                return 1;
 843        while (with_commit) {
 844                struct commit *other;
 845
 846                other = with_commit->item;
 847                with_commit = with_commit->next;
 848                if (in_merge_bases(other, commit))
 849                        return 1;
 850        }
 851        return 0;
 852}
 853
 854/*
 855 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 856 */
 857int in_merge_bases(struct commit *commit, struct commit *reference)
 858{
 859        struct commit_list *bases;
 860        int ret = 0;
 861
 862        if (parse_commit(commit) || parse_commit(reference))
 863                return ret;
 864
 865        bases = paint_down_to_common(commit, 1, &reference);
 866        if (commit->object.flags & PARENT2)
 867                ret = 1;
 868        clear_commit_marks(commit, all_flags);
 869        clear_commit_marks(reference, all_flags);
 870        free_commit_list(bases);
 871        return ret;
 872}
 873
 874struct commit_list *reduce_heads(struct commit_list *heads)
 875{
 876        struct commit_list *p;
 877        struct commit_list *result = NULL, **tail = &result;
 878        struct commit **array;
 879        int num_head, i;
 880
 881        if (!heads)
 882                return NULL;
 883
 884        /* Uniquify */
 885        for (p = heads; p; p = p->next)
 886                p->item->object.flags &= ~STALE;
 887        for (p = heads, num_head = 0; p; p = p->next) {
 888                if (p->item->object.flags & STALE)
 889                        continue;
 890                p->item->object.flags |= STALE;
 891                num_head++;
 892        }
 893        array = xcalloc(sizeof(*array), num_head);
 894        for (p = heads, i = 0; p; p = p->next) {
 895                if (p->item->object.flags & STALE) {
 896                        array[i++] = p->item;
 897                        p->item->object.flags &= ~STALE;
 898                }
 899        }
 900        num_head = remove_redundant(array, num_head);
 901        for (i = 0; i < num_head; i++)
 902                tail = &commit_list_insert(array[i], tail)->next;
 903        return result;
 904}
 905
 906static const char gpg_sig_header[] = "gpgsig";
 907static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 908
 909static int do_sign_commit(struct strbuf *buf, const char *keyid)
 910{
 911        struct strbuf sig = STRBUF_INIT;
 912        int inspos, copypos;
 913
 914        /* find the end of the header */
 915        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
 916
 917        if (!keyid || !*keyid)
 918                keyid = get_signing_key();
 919        if (sign_buffer(buf, &sig, keyid)) {
 920                strbuf_release(&sig);
 921                return -1;
 922        }
 923
 924        for (copypos = 0; sig.buf[copypos]; ) {
 925                const char *bol = sig.buf + copypos;
 926                const char *eol = strchrnul(bol, '\n');
 927                int len = (eol - bol) + !!*eol;
 928
 929                if (!copypos) {
 930                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 931                        inspos += gpg_sig_header_len;
 932                }
 933                strbuf_insert(buf, inspos++, " ", 1);
 934                strbuf_insert(buf, inspos, bol, len);
 935                inspos += len;
 936                copypos += len;
 937        }
 938        strbuf_release(&sig);
 939        return 0;
 940}
 941
 942int parse_signed_commit(const unsigned char *sha1,
 943                        struct strbuf *payload, struct strbuf *signature)
 944{
 945        unsigned long size;
 946        enum object_type type;
 947        char *buffer = read_sha1_file(sha1, &type, &size);
 948        int in_signature, saw_signature = -1;
 949        char *line, *tail;
 950
 951        if (!buffer || type != OBJ_COMMIT)
 952                goto cleanup;
 953
 954        line = buffer;
 955        tail = buffer + size;
 956        in_signature = 0;
 957        saw_signature = 0;
 958        while (line < tail) {
 959                const char *sig = NULL;
 960                char *next = memchr(line, '\n', tail - line);
 961
 962                next = next ? next + 1 : tail;
 963                if (in_signature && line[0] == ' ')
 964                        sig = line + 1;
 965                else if (!prefixcmp(line, gpg_sig_header) &&
 966                         line[gpg_sig_header_len] == ' ')
 967                        sig = line + gpg_sig_header_len + 1;
 968                if (sig) {
 969                        strbuf_add(signature, sig, next - sig);
 970                        saw_signature = 1;
 971                        in_signature = 1;
 972                } else {
 973                        if (*line == '\n')
 974                                /* dump the whole remainder of the buffer */
 975                                next = tail;
 976                        strbuf_add(payload, line, next - line);
 977                        in_signature = 0;
 978                }
 979                line = next;
 980        }
 981 cleanup:
 982        free(buffer);
 983        return saw_signature;
 984}
 985
 986static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 987{
 988        struct merge_remote_desc *desc;
 989        struct commit_extra_header *mergetag;
 990        char *buf;
 991        unsigned long size, len;
 992        enum object_type type;
 993
 994        desc = merge_remote_util(parent);
 995        if (!desc || !desc->obj)
 996                return;
 997        buf = read_sha1_file(desc->obj->sha1, &type, &size);
 998        if (!buf || type != OBJ_TAG)
 999                goto free_return;
1000        len = parse_signature(buf, size);
1001        if (size == len)
1002                goto free_return;
1003        /*
1004         * We could verify this signature and either omit the tag when
1005         * it does not validate, but the integrator may not have the
1006         * public key of the signer of the tag he is merging, while a
1007         * later auditor may have it while auditing, so let's not run
1008         * verify-signed-buffer here for now...
1009         *
1010         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1011         *      warn("warning: signed tag unverified.");
1012         */
1013        mergetag = xcalloc(1, sizeof(*mergetag));
1014        mergetag->key = xstrdup("mergetag");
1015        mergetag->value = buf;
1016        mergetag->len = size;
1017
1018        **tail = mergetag;
1019        *tail = &mergetag->next;
1020        return;
1021
1022free_return:
1023        free(buf);
1024}
1025
1026void append_merge_tag_headers(struct commit_list *parents,
1027                              struct commit_extra_header ***tail)
1028{
1029        while (parents) {
1030                struct commit *parent = parents->item;
1031                handle_signed_tag(parent, tail);
1032                parents = parents->next;
1033        }
1034}
1035
1036static void add_extra_header(struct strbuf *buffer,
1037                             struct commit_extra_header *extra)
1038{
1039        strbuf_addstr(buffer, extra->key);
1040        if (extra->len)
1041                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1042        else
1043                strbuf_addch(buffer, '\n');
1044}
1045
1046struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1047                                                      const char **exclude)
1048{
1049        struct commit_extra_header *extra = NULL;
1050        unsigned long size;
1051        enum object_type type;
1052        char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1053        if (buffer && type == OBJ_COMMIT)
1054                extra = read_commit_extra_header_lines(buffer, size, exclude);
1055        free(buffer);
1056        return extra;
1057}
1058
1059static inline int standard_header_field(const char *field, size_t len)
1060{
1061        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1062                (len == 6 && !memcmp(field, "parent ", 7)) ||
1063                (len == 6 && !memcmp(field, "author ", 7)) ||
1064                (len == 9 && !memcmp(field, "committer ", 10)) ||
1065                (len == 8 && !memcmp(field, "encoding ", 9)));
1066}
1067
1068static int excluded_header_field(const char *field, size_t len, const char **exclude)
1069{
1070        if (!exclude)
1071                return 0;
1072
1073        while (*exclude) {
1074                size_t xlen = strlen(*exclude);
1075                if (len == xlen &&
1076                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1077                        return 1;
1078                exclude++;
1079        }
1080        return 0;
1081}
1082
1083static struct commit_extra_header *read_commit_extra_header_lines(
1084        const char *buffer, size_t size,
1085        const char **exclude)
1086{
1087        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1088        const char *line, *next, *eof, *eob;
1089        struct strbuf buf = STRBUF_INIT;
1090
1091        for (line = buffer, eob = line + size;
1092             line < eob && *line != '\n';
1093             line = next) {
1094                next = memchr(line, '\n', eob - line);
1095                next = next ? next + 1 : eob;
1096                if (*line == ' ') {
1097                        /* continuation */
1098                        if (it)
1099                                strbuf_add(&buf, line + 1, next - (line + 1));
1100                        continue;
1101                }
1102                if (it)
1103                        it->value = strbuf_detach(&buf, &it->len);
1104                strbuf_reset(&buf);
1105                it = NULL;
1106
1107                eof = strchr(line, ' ');
1108                if (next <= eof)
1109                        eof = next;
1110
1111                if (standard_header_field(line, eof - line) ||
1112                    excluded_header_field(line, eof - line, exclude))
1113                        continue;
1114
1115                it = xcalloc(1, sizeof(*it));
1116                it->key = xmemdupz(line, eof-line);
1117                *tail = it;
1118                tail = &it->next;
1119                if (eof + 1 < next)
1120                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1121        }
1122        if (it)
1123                it->value = strbuf_detach(&buf, &it->len);
1124        return extra;
1125}
1126
1127void free_commit_extra_headers(struct commit_extra_header *extra)
1128{
1129        while (extra) {
1130                struct commit_extra_header *next = extra->next;
1131                free(extra->key);
1132                free(extra->value);
1133                free(extra);
1134                extra = next;
1135        }
1136}
1137
1138int commit_tree(const struct strbuf *msg, unsigned char *tree,
1139                struct commit_list *parents, unsigned char *ret,
1140                const char *author, const char *sign_commit)
1141{
1142        struct commit_extra_header *extra = NULL, **tail = &extra;
1143        int result;
1144
1145        append_merge_tag_headers(parents, &tail);
1146        result = commit_tree_extended(msg, tree, parents, ret,
1147                                      author, sign_commit, extra);
1148        free_commit_extra_headers(extra);
1149        return result;
1150}
1151
1152static int find_invalid_utf8(const char *buf, int len)
1153{
1154        int offset = 0;
1155
1156        while (len) {
1157                unsigned char c = *buf++;
1158                int bytes, bad_offset;
1159
1160                len--;
1161                offset++;
1162
1163                /* Simple US-ASCII? No worries. */
1164                if (c < 0x80)
1165                        continue;
1166
1167                bad_offset = offset-1;
1168
1169                /*
1170                 * Count how many more high bits set: that's how
1171                 * many more bytes this sequence should have.
1172                 */
1173                bytes = 0;
1174                while (c & 0x40) {
1175                        c <<= 1;
1176                        bytes++;
1177                }
1178
1179                /* Must be between 1 and 5 more bytes */
1180                if (bytes < 1 || bytes > 5)
1181                        return bad_offset;
1182
1183                /* Do we *have* that many bytes? */
1184                if (len < bytes)
1185                        return bad_offset;
1186
1187                offset += bytes;
1188                len -= bytes;
1189
1190                /* And verify that they are good continuation bytes */
1191                do {
1192                        if ((*buf++ & 0xc0) != 0x80)
1193                                return bad_offset;
1194                } while (--bytes);
1195
1196                /* We could/should check the value and length here too */
1197        }
1198        return -1;
1199}
1200
1201/*
1202 * This verifies that the buffer is in proper utf8 format.
1203 *
1204 * If it isn't, it assumes any non-utf8 characters are Latin1,
1205 * and does the conversion.
1206 *
1207 * Fixme: we should probably also disallow overlong forms and
1208 * invalid characters. But we don't do that currently.
1209 */
1210static int verify_utf8(struct strbuf *buf)
1211{
1212        int ok = 1;
1213        long pos = 0;
1214
1215        for (;;) {
1216                int bad;
1217                unsigned char c;
1218                unsigned char replace[2];
1219
1220                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1221                if (bad < 0)
1222                        return ok;
1223                pos += bad;
1224                ok = 0;
1225                c = buf->buf[pos];
1226                strbuf_remove(buf, pos, 1);
1227
1228                /* We know 'c' must be in the range 128-255 */
1229                replace[0] = 0xc0 + (c >> 6);
1230                replace[1] = 0x80 + (c & 0x3f);
1231                strbuf_insert(buf, pos, replace, 2);
1232                pos += 2;
1233        }
1234}
1235
1236static const char commit_utf8_warn[] =
1237"Warning: commit message did not conform to UTF-8.\n"
1238"You may want to amend it after fixing the message, or set the config\n"
1239"variable i18n.commitencoding to the encoding your project uses.\n";
1240
1241int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1242                         struct commit_list *parents, unsigned char *ret,
1243                         const char *author, const char *sign_commit,
1244                         struct commit_extra_header *extra)
1245{
1246        int result;
1247        int encoding_is_utf8;
1248        struct strbuf buffer;
1249
1250        assert_sha1_type(tree, OBJ_TREE);
1251
1252        if (memchr(msg->buf, '\0', msg->len))
1253                return error("a NUL byte in commit log message not allowed.");
1254
1255        /* Not having i18n.commitencoding is the same as having utf-8 */
1256        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1257
1258        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1259        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1260
1261        /*
1262         * NOTE! This ordering means that the same exact tree merged with a
1263         * different order of parents will be a _different_ changeset even
1264         * if everything else stays the same.
1265         */
1266        while (parents) {
1267                struct commit_list *next = parents->next;
1268                struct commit *parent = parents->item;
1269
1270                strbuf_addf(&buffer, "parent %s\n",
1271                            sha1_to_hex(parent->object.sha1));
1272                free(parents);
1273                parents = next;
1274        }
1275
1276        /* Person/date information */
1277        if (!author)
1278                author = git_author_info(IDENT_STRICT);
1279        strbuf_addf(&buffer, "author %s\n", author);
1280        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1281        if (!encoding_is_utf8)
1282                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1283
1284        while (extra) {
1285                add_extra_header(&buffer, extra);
1286                extra = extra->next;
1287        }
1288        strbuf_addch(&buffer, '\n');
1289
1290        /* And add the comment */
1291        strbuf_addbuf(&buffer, msg);
1292
1293        /* And check the encoding */
1294        if (encoding_is_utf8 && !verify_utf8(&buffer))
1295                fprintf(stderr, commit_utf8_warn);
1296
1297        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1298                return -1;
1299
1300        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1301        strbuf_release(&buffer);
1302        return result;
1303}
1304
1305struct commit *get_merge_parent(const char *name)
1306{
1307        struct object *obj;
1308        struct commit *commit;
1309        unsigned char sha1[20];
1310        if (get_sha1(name, sha1))
1311                return NULL;
1312        obj = parse_object(sha1);
1313        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1314        if (commit && !commit->util) {
1315                struct merge_remote_desc *desc;
1316                desc = xmalloc(sizeof(*desc));
1317                desc->obj = obj;
1318                desc->name = strdup(name);
1319                commit->util = desc;
1320        }
1321        return commit;
1322}
1323
1324/*
1325 * Append a commit to the end of the commit_list.
1326 *
1327 * next starts by pointing to the variable that holds the head of an
1328 * empty commit_list, and is updated to point to the "next" field of
1329 * the last item on the list as new commits are appended.
1330 *
1331 * Usage example:
1332 *
1333 *     struct commit_list *list;
1334 *     struct commit_list **next = &list;
1335 *
1336 *     next = commit_list_append(c1, next);
1337 *     next = commit_list_append(c2, next);
1338 *     assert(commit_list_count(list) == 2);
1339 *     return list;
1340 */
1341struct commit_list **commit_list_append(struct commit *commit,
1342                                        struct commit_list **next)
1343{
1344        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1345        new->item = commit;
1346        *next = new;
1347        new->next = NULL;
1348        return &new->next;
1349}
1350
1351void print_commit_list(struct commit_list *list,
1352                       const char *format_cur,
1353                       const char *format_last)
1354{
1355        for ( ; list; list = list->next) {
1356                const char *format = list->next ? format_cur : format_last;
1357                printf(format, sha1_to_hex(list->item->object.sha1));
1358        }
1359}