Andrew's git / gitweb.git / commit.c
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commit.con commit Merge branch 'jk/empty-archive' (63868f6)
   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_many(int nr, struct commit **commit, unsigned int mark)
 467{
 468        struct commit_list *list = NULL;
 469
 470        while (nr--) {
 471                commit_list_insert(*commit, &list);
 472                commit++;
 473        }
 474        while (list)
 475                clear_commit_marks_1(&list, pop_commit(&list), mark);
 476}
 477
 478void clear_commit_marks(struct commit *commit, unsigned int mark)
 479{
 480        clear_commit_marks_many(1, &commit, mark);
 481}
 482
 483void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 484{
 485        struct object *object;
 486        struct commit *commit;
 487        unsigned int i;
 488
 489        for (i = 0; i < a->nr; i++) {
 490                object = a->objects[i].item;
 491                commit = lookup_commit_reference_gently(object->sha1, 1);
 492                if (commit)
 493                        clear_commit_marks(commit, mark);
 494        }
 495}
 496
 497struct commit *pop_commit(struct commit_list **stack)
 498{
 499        struct commit_list *top = *stack;
 500        struct commit *item = top ? top->item : NULL;
 501
 502        if (top) {
 503                *stack = top->next;
 504                free(top);
 505        }
 506        return item;
 507}
 508
 509/*
 510 * Performs an in-place topological sort on the list supplied.
 511 */
 512void sort_in_topological_order(struct commit_list ** list, int lifo)
 513{
 514        struct commit_list *next, *orig = *list;
 515        struct commit_list *work, **insert;
 516        struct commit_list **pptr;
 517
 518        if (!orig)
 519                return;
 520        *list = NULL;
 521
 522        /* Mark them and clear the indegree */
 523        for (next = orig; next; next = next->next) {
 524                struct commit *commit = next->item;
 525                commit->indegree = 1;
 526        }
 527
 528        /* update the indegree */
 529        for (next = orig; next; next = next->next) {
 530                struct commit_list * parents = next->item->parents;
 531                while (parents) {
 532                        struct commit *parent = parents->item;
 533
 534                        if (parent->indegree)
 535                                parent->indegree++;
 536                        parents = parents->next;
 537                }
 538        }
 539
 540        /*
 541         * find the tips
 542         *
 543         * tips are nodes not reachable from any other node in the list
 544         *
 545         * the tips serve as a starting set for the work queue.
 546         */
 547        work = NULL;
 548        insert = &work;
 549        for (next = orig; next; next = next->next) {
 550                struct commit *commit = next->item;
 551
 552                if (commit->indegree == 1)
 553                        insert = &commit_list_insert(commit, insert)->next;
 554        }
 555
 556        /* process the list in topological order */
 557        if (!lifo)
 558                commit_list_sort_by_date(&work);
 559
 560        pptr = list;
 561        *list = NULL;
 562        while (work) {
 563                struct commit *commit;
 564                struct commit_list *parents, *work_item;
 565
 566                work_item = work;
 567                work = work_item->next;
 568                work_item->next = NULL;
 569
 570                commit = work_item->item;
 571                for (parents = commit->parents; parents ; parents = parents->next) {
 572                        struct commit *parent = parents->item;
 573
 574                        if (!parent->indegree)
 575                                continue;
 576
 577                        /*
 578                         * parents are only enqueued for emission
 579                         * when all their children have been emitted thereby
 580                         * guaranteeing topological order.
 581                         */
 582                        if (--parent->indegree == 1) {
 583                                if (!lifo)
 584                                        commit_list_insert_by_date(parent, &work);
 585                                else
 586                                        commit_list_insert(parent, &work);
 587                        }
 588                }
 589                /*
 590                 * work_item is a commit all of whose children
 591                 * have already been emitted. we can emit it now.
 592                 */
 593                commit->indegree = 0;
 594                *pptr = work_item;
 595                pptr = &work_item->next;
 596        }
 597}
 598
 599/* merge-base stuff */
 600
 601/* bits #0..15 in revision.h */
 602#define PARENT1         (1u<<16)
 603#define PARENT2         (1u<<17)
 604#define STALE           (1u<<18)
 605#define RESULT          (1u<<19)
 606
 607static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 608
 609static struct commit *interesting(struct commit_list *list)
 610{
 611        while (list) {
 612                struct commit *commit = list->item;
 613                list = list->next;
 614                if (commit->object.flags & STALE)
 615                        continue;
 616                return commit;
 617        }
 618        return NULL;
 619}
 620
 621/* all input commits in one and twos[] must have been parsed! */
 622static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 623{
 624        struct commit_list *list = NULL;
 625        struct commit_list *result = NULL;
 626        int i;
 627
 628        one->object.flags |= PARENT1;
 629        commit_list_insert_by_date(one, &list);
 630        if (!n)
 631                return list;
 632        for (i = 0; i < n; i++) {
 633                twos[i]->object.flags |= PARENT2;
 634                commit_list_insert_by_date(twos[i], &list);
 635        }
 636
 637        while (interesting(list)) {
 638                struct commit *commit;
 639                struct commit_list *parents;
 640                struct commit_list *next;
 641                int flags;
 642
 643                commit = list->item;
 644                next = list->next;
 645                free(list);
 646                list = next;
 647
 648                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 649                if (flags == (PARENT1 | PARENT2)) {
 650                        if (!(commit->object.flags & RESULT)) {
 651                                commit->object.flags |= RESULT;
 652                                commit_list_insert_by_date(commit, &result);
 653                        }
 654                        /* Mark parents of a found merge stale */
 655                        flags |= STALE;
 656                }
 657                parents = commit->parents;
 658                while (parents) {
 659                        struct commit *p = parents->item;
 660                        parents = parents->next;
 661                        if ((p->object.flags & flags) == flags)
 662                                continue;
 663                        if (parse_commit(p))
 664                                return NULL;
 665                        p->object.flags |= flags;
 666                        commit_list_insert_by_date(p, &list);
 667                }
 668        }
 669
 670        free_commit_list(list);
 671        return result;
 672}
 673
 674static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 675{
 676        struct commit_list *list = NULL;
 677        struct commit_list *result = NULL;
 678        int i;
 679
 680        for (i = 0; i < n; i++) {
 681                if (one == twos[i])
 682                        /*
 683                         * We do not mark this even with RESULT so we do not
 684                         * have to clean it up.
 685                         */
 686                        return commit_list_insert(one, &result);
 687        }
 688
 689        if (parse_commit(one))
 690                return NULL;
 691        for (i = 0; i < n; i++) {
 692                if (parse_commit(twos[i]))
 693                        return NULL;
 694        }
 695
 696        list = paint_down_to_common(one, n, twos);
 697
 698        while (list) {
 699                struct commit_list *next = list->next;
 700                if (!(list->item->object.flags & STALE))
 701                        commit_list_insert_by_date(list->item, &result);
 702                free(list);
 703                list = next;
 704        }
 705        return result;
 706}
 707
 708struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 709{
 710        struct commit_list *i, *j, *k, *ret = NULL;
 711        struct commit_list **pptr = &ret;
 712
 713        for (i = in; i; i = i->next) {
 714                if (!ret)
 715                        pptr = &commit_list_insert(i->item, pptr)->next;
 716                else {
 717                        struct commit_list *new = NULL, *end = NULL;
 718
 719                        for (j = ret; j; j = j->next) {
 720                                struct commit_list *bases;
 721                                bases = get_merge_bases(i->item, j->item, 1);
 722                                if (!new)
 723                                        new = bases;
 724                                else
 725                                        end->next = bases;
 726                                for (k = bases; k; k = k->next)
 727                                        end = k;
 728                        }
 729                        ret = new;
 730                }
 731        }
 732        return ret;
 733}
 734
 735static int remove_redundant(struct commit **array, int cnt)
 736{
 737        /*
 738         * Some commit in the array may be an ancestor of
 739         * another commit.  Move such commit to the end of
 740         * the array, and return the number of commits that
 741         * are independent from each other.
 742         */
 743        struct commit **work;
 744        unsigned char *redundant;
 745        int *filled_index;
 746        int i, j, filled;
 747
 748        work = xcalloc(cnt, sizeof(*work));
 749        redundant = xcalloc(cnt, 1);
 750        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 751
 752        for (i = 0; i < cnt; i++)
 753                parse_commit(array[i]);
 754        for (i = 0; i < cnt; i++) {
 755                struct commit_list *common;
 756
 757                if (redundant[i])
 758                        continue;
 759                for (j = filled = 0; j < cnt; j++) {
 760                        if (i == j || redundant[j])
 761                                continue;
 762                        filled_index[filled] = j;
 763                        work[filled++] = array[j];
 764                }
 765                common = paint_down_to_common(array[i], filled, work);
 766                if (array[i]->object.flags & PARENT2)
 767                        redundant[i] = 1;
 768                for (j = 0; j < filled; j++)
 769                        if (work[j]->object.flags & PARENT1)
 770                                redundant[filled_index[j]] = 1;
 771                clear_commit_marks(array[i], all_flags);
 772                for (j = 0; j < filled; j++)
 773                        clear_commit_marks(work[j], all_flags);
 774                free_commit_list(common);
 775        }
 776
 777        /* Now collect the result */
 778        memcpy(work, array, sizeof(*array) * cnt);
 779        for (i = filled = 0; i < cnt; i++)
 780                if (!redundant[i])
 781                        array[filled++] = work[i];
 782        for (j = filled, i = 0; i < cnt; i++)
 783                if (redundant[i])
 784                        array[j++] = work[i];
 785        free(work);
 786        free(redundant);
 787        free(filled_index);
 788        return filled;
 789}
 790
 791struct commit_list *get_merge_bases_many(struct commit *one,
 792                                         int n,
 793                                         struct commit **twos,
 794                                         int cleanup)
 795{
 796        struct commit_list *list;
 797        struct commit **rslt;
 798        struct commit_list *result;
 799        int cnt, i;
 800
 801        result = merge_bases_many(one, n, twos);
 802        for (i = 0; i < n; i++) {
 803                if (one == twos[i])
 804                        return result;
 805        }
 806        if (!result || !result->next) {
 807                if (cleanup) {
 808                        clear_commit_marks(one, all_flags);
 809                        clear_commit_marks_many(n, twos, all_flags);
 810                }
 811                return result;
 812        }
 813
 814        /* There are more than one */
 815        cnt = 0;
 816        list = result;
 817        while (list) {
 818                list = list->next;
 819                cnt++;
 820        }
 821        rslt = xcalloc(cnt, sizeof(*rslt));
 822        for (list = result, i = 0; list; list = list->next)
 823                rslt[i++] = list->item;
 824        free_commit_list(result);
 825
 826        clear_commit_marks(one, all_flags);
 827        clear_commit_marks_many(n, twos, all_flags);
 828
 829        cnt = remove_redundant(rslt, cnt);
 830        result = NULL;
 831        for (i = 0; i < cnt; i++)
 832                commit_list_insert_by_date(rslt[i], &result);
 833        free(rslt);
 834        return result;
 835}
 836
 837struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 838                                    int cleanup)
 839{
 840        return get_merge_bases_many(one, 1, &two, cleanup);
 841}
 842
 843/*
 844 * Is "commit" a decendant of one of the elements on the "with_commit" list?
 845 */
 846int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 847{
 848        if (!with_commit)
 849                return 1;
 850        while (with_commit) {
 851                struct commit *other;
 852
 853                other = with_commit->item;
 854                with_commit = with_commit->next;
 855                if (in_merge_bases(other, commit))
 856                        return 1;
 857        }
 858        return 0;
 859}
 860
 861/*
 862 * Is "commit" an ancestor of one of the "references"?
 863 */
 864int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 865{
 866        struct commit_list *bases;
 867        int ret = 0, i;
 868
 869        if (parse_commit(commit))
 870                return ret;
 871        for (i = 0; i < nr_reference; i++)
 872                if (parse_commit(reference[i]))
 873                        return ret;
 874
 875        bases = paint_down_to_common(commit, nr_reference, reference);
 876        if (commit->object.flags & PARENT2)
 877                ret = 1;
 878        clear_commit_marks(commit, all_flags);
 879        clear_commit_marks_many(nr_reference, reference, all_flags);
 880        free_commit_list(bases);
 881        return ret;
 882}
 883
 884/*
 885 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 886 */
 887int in_merge_bases(struct commit *commit, struct commit *reference)
 888{
 889        return in_merge_bases_many(commit, 1, &reference);
 890}
 891
 892struct commit_list *reduce_heads(struct commit_list *heads)
 893{
 894        struct commit_list *p;
 895        struct commit_list *result = NULL, **tail = &result;
 896        struct commit **array;
 897        int num_head, i;
 898
 899        if (!heads)
 900                return NULL;
 901
 902        /* Uniquify */
 903        for (p = heads; p; p = p->next)
 904                p->item->object.flags &= ~STALE;
 905        for (p = heads, num_head = 0; p; p = p->next) {
 906                if (p->item->object.flags & STALE)
 907                        continue;
 908                p->item->object.flags |= STALE;
 909                num_head++;
 910        }
 911        array = xcalloc(sizeof(*array), num_head);
 912        for (p = heads, i = 0; p; p = p->next) {
 913                if (p->item->object.flags & STALE) {
 914                        array[i++] = p->item;
 915                        p->item->object.flags &= ~STALE;
 916                }
 917        }
 918        num_head = remove_redundant(array, num_head);
 919        for (i = 0; i < num_head; i++)
 920                tail = &commit_list_insert(array[i], tail)->next;
 921        return result;
 922}
 923
 924static const char gpg_sig_header[] = "gpgsig";
 925static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 926
 927static int do_sign_commit(struct strbuf *buf, const char *keyid)
 928{
 929        struct strbuf sig = STRBUF_INIT;
 930        int inspos, copypos;
 931
 932        /* find the end of the header */
 933        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
 934
 935        if (!keyid || !*keyid)
 936                keyid = get_signing_key();
 937        if (sign_buffer(buf, &sig, keyid)) {
 938                strbuf_release(&sig);
 939                return -1;
 940        }
 941
 942        for (copypos = 0; sig.buf[copypos]; ) {
 943                const char *bol = sig.buf + copypos;
 944                const char *eol = strchrnul(bol, '\n');
 945                int len = (eol - bol) + !!*eol;
 946
 947                if (!copypos) {
 948                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 949                        inspos += gpg_sig_header_len;
 950                }
 951                strbuf_insert(buf, inspos++, " ", 1);
 952                strbuf_insert(buf, inspos, bol, len);
 953                inspos += len;
 954                copypos += len;
 955        }
 956        strbuf_release(&sig);
 957        return 0;
 958}
 959
 960int parse_signed_commit(const unsigned char *sha1,
 961                        struct strbuf *payload, struct strbuf *signature)
 962{
 963        unsigned long size;
 964        enum object_type type;
 965        char *buffer = read_sha1_file(sha1, &type, &size);
 966        int in_signature, saw_signature = -1;
 967        char *line, *tail;
 968
 969        if (!buffer || type != OBJ_COMMIT)
 970                goto cleanup;
 971
 972        line = buffer;
 973        tail = buffer + size;
 974        in_signature = 0;
 975        saw_signature = 0;
 976        while (line < tail) {
 977                const char *sig = NULL;
 978                char *next = memchr(line, '\n', tail - line);
 979
 980                next = next ? next + 1 : tail;
 981                if (in_signature && line[0] == ' ')
 982                        sig = line + 1;
 983                else if (!prefixcmp(line, gpg_sig_header) &&
 984                         line[gpg_sig_header_len] == ' ')
 985                        sig = line + gpg_sig_header_len + 1;
 986                if (sig) {
 987                        strbuf_add(signature, sig, next - sig);
 988                        saw_signature = 1;
 989                        in_signature = 1;
 990                } else {
 991                        if (*line == '\n')
 992                                /* dump the whole remainder of the buffer */
 993                                next = tail;
 994                        strbuf_add(payload, line, next - line);
 995                        in_signature = 0;
 996                }
 997                line = next;
 998        }
 999 cleanup:
1000        free(buffer);
1001        return saw_signature;
1002}
1003
1004static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1005{
1006        struct merge_remote_desc *desc;
1007        struct commit_extra_header *mergetag;
1008        char *buf;
1009        unsigned long size, len;
1010        enum object_type type;
1011
1012        desc = merge_remote_util(parent);
1013        if (!desc || !desc->obj)
1014                return;
1015        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1016        if (!buf || type != OBJ_TAG)
1017                goto free_return;
1018        len = parse_signature(buf, size);
1019        if (size == len)
1020                goto free_return;
1021        /*
1022         * We could verify this signature and either omit the tag when
1023         * it does not validate, but the integrator may not have the
1024         * public key of the signer of the tag he is merging, while a
1025         * later auditor may have it while auditing, so let's not run
1026         * verify-signed-buffer here for now...
1027         *
1028         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1029         *      warn("warning: signed tag unverified.");
1030         */
1031        mergetag = xcalloc(1, sizeof(*mergetag));
1032        mergetag->key = xstrdup("mergetag");
1033        mergetag->value = buf;
1034        mergetag->len = size;
1035
1036        **tail = mergetag;
1037        *tail = &mergetag->next;
1038        return;
1039
1040free_return:
1041        free(buf);
1042}
1043
1044void append_merge_tag_headers(struct commit_list *parents,
1045                              struct commit_extra_header ***tail)
1046{
1047        while (parents) {
1048                struct commit *parent = parents->item;
1049                handle_signed_tag(parent, tail);
1050                parents = parents->next;
1051        }
1052}
1053
1054static void add_extra_header(struct strbuf *buffer,
1055                             struct commit_extra_header *extra)
1056{
1057        strbuf_addstr(buffer, extra->key);
1058        if (extra->len)
1059                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1060        else
1061                strbuf_addch(buffer, '\n');
1062}
1063
1064struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1065                                                      const char **exclude)
1066{
1067        struct commit_extra_header *extra = NULL;
1068        unsigned long size;
1069        enum object_type type;
1070        char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1071        if (buffer && type == OBJ_COMMIT)
1072                extra = read_commit_extra_header_lines(buffer, size, exclude);
1073        free(buffer);
1074        return extra;
1075}
1076
1077static inline int standard_header_field(const char *field, size_t len)
1078{
1079        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1080                (len == 6 && !memcmp(field, "parent ", 7)) ||
1081                (len == 6 && !memcmp(field, "author ", 7)) ||
1082                (len == 9 && !memcmp(field, "committer ", 10)) ||
1083                (len == 8 && !memcmp(field, "encoding ", 9)));
1084}
1085
1086static int excluded_header_field(const char *field, size_t len, const char **exclude)
1087{
1088        if (!exclude)
1089                return 0;
1090
1091        while (*exclude) {
1092                size_t xlen = strlen(*exclude);
1093                if (len == xlen &&
1094                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1095                        return 1;
1096                exclude++;
1097        }
1098        return 0;
1099}
1100
1101static struct commit_extra_header *read_commit_extra_header_lines(
1102        const char *buffer, size_t size,
1103        const char **exclude)
1104{
1105        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1106        const char *line, *next, *eof, *eob;
1107        struct strbuf buf = STRBUF_INIT;
1108
1109        for (line = buffer, eob = line + size;
1110             line < eob && *line != '\n';
1111             line = next) {
1112                next = memchr(line, '\n', eob - line);
1113                next = next ? next + 1 : eob;
1114                if (*line == ' ') {
1115                        /* continuation */
1116                        if (it)
1117                                strbuf_add(&buf, line + 1, next - (line + 1));
1118                        continue;
1119                }
1120                if (it)
1121                        it->value = strbuf_detach(&buf, &it->len);
1122                strbuf_reset(&buf);
1123                it = NULL;
1124
1125                eof = strchr(line, ' ');
1126                if (next <= eof)
1127                        eof = next;
1128
1129                if (standard_header_field(line, eof - line) ||
1130                    excluded_header_field(line, eof - line, exclude))
1131                        continue;
1132
1133                it = xcalloc(1, sizeof(*it));
1134                it->key = xmemdupz(line, eof-line);
1135                *tail = it;
1136                tail = &it->next;
1137                if (eof + 1 < next)
1138                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1139        }
1140        if (it)
1141                it->value = strbuf_detach(&buf, &it->len);
1142        return extra;
1143}
1144
1145void free_commit_extra_headers(struct commit_extra_header *extra)
1146{
1147        while (extra) {
1148                struct commit_extra_header *next = extra->next;
1149                free(extra->key);
1150                free(extra->value);
1151                free(extra);
1152                extra = next;
1153        }
1154}
1155
1156int commit_tree(const struct strbuf *msg, unsigned char *tree,
1157                struct commit_list *parents, unsigned char *ret,
1158                const char *author, const char *sign_commit)
1159{
1160        struct commit_extra_header *extra = NULL, **tail = &extra;
1161        int result;
1162
1163        append_merge_tag_headers(parents, &tail);
1164        result = commit_tree_extended(msg, tree, parents, ret,
1165                                      author, sign_commit, extra);
1166        free_commit_extra_headers(extra);
1167        return result;
1168}
1169
1170static int find_invalid_utf8(const char *buf, int len)
1171{
1172        int offset = 0;
1173
1174        while (len) {
1175                unsigned char c = *buf++;
1176                int bytes, bad_offset;
1177
1178                len--;
1179                offset++;
1180
1181                /* Simple US-ASCII? No worries. */
1182                if (c < 0x80)
1183                        continue;
1184
1185                bad_offset = offset-1;
1186
1187                /*
1188                 * Count how many more high bits set: that's how
1189                 * many more bytes this sequence should have.
1190                 */
1191                bytes = 0;
1192                while (c & 0x40) {
1193                        c <<= 1;
1194                        bytes++;
1195                }
1196
1197                /* Must be between 1 and 5 more bytes */
1198                if (bytes < 1 || bytes > 5)
1199                        return bad_offset;
1200
1201                /* Do we *have* that many bytes? */
1202                if (len < bytes)
1203                        return bad_offset;
1204
1205                offset += bytes;
1206                len -= bytes;
1207
1208                /* And verify that they are good continuation bytes */
1209                do {
1210                        if ((*buf++ & 0xc0) != 0x80)
1211                                return bad_offset;
1212                } while (--bytes);
1213
1214                /* We could/should check the value and length here too */
1215        }
1216        return -1;
1217}
1218
1219/*
1220 * This verifies that the buffer is in proper utf8 format.
1221 *
1222 * If it isn't, it assumes any non-utf8 characters are Latin1,
1223 * and does the conversion.
1224 *
1225 * Fixme: we should probably also disallow overlong forms and
1226 * invalid characters. But we don't do that currently.
1227 */
1228static int verify_utf8(struct strbuf *buf)
1229{
1230        int ok = 1;
1231        long pos = 0;
1232
1233        for (;;) {
1234                int bad;
1235                unsigned char c;
1236                unsigned char replace[2];
1237
1238                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1239                if (bad < 0)
1240                        return ok;
1241                pos += bad;
1242                ok = 0;
1243                c = buf->buf[pos];
1244                strbuf_remove(buf, pos, 1);
1245
1246                /* We know 'c' must be in the range 128-255 */
1247                replace[0] = 0xc0 + (c >> 6);
1248                replace[1] = 0x80 + (c & 0x3f);
1249                strbuf_insert(buf, pos, replace, 2);
1250                pos += 2;
1251        }
1252}
1253
1254static const char commit_utf8_warn[] =
1255"Warning: commit message did not conform to UTF-8.\n"
1256"You may want to amend it after fixing the message, or set the config\n"
1257"variable i18n.commitencoding to the encoding your project uses.\n";
1258
1259int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1260                         struct commit_list *parents, unsigned char *ret,
1261                         const char *author, const char *sign_commit,
1262                         struct commit_extra_header *extra)
1263{
1264        int result;
1265        int encoding_is_utf8;
1266        struct strbuf buffer;
1267
1268        assert_sha1_type(tree, OBJ_TREE);
1269
1270        if (memchr(msg->buf, '\0', msg->len))
1271                return error("a NUL byte in commit log message not allowed.");
1272
1273        /* Not having i18n.commitencoding is the same as having utf-8 */
1274        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1275
1276        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1277        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1278
1279        /*
1280         * NOTE! This ordering means that the same exact tree merged with a
1281         * different order of parents will be a _different_ changeset even
1282         * if everything else stays the same.
1283         */
1284        while (parents) {
1285                struct commit_list *next = parents->next;
1286                struct commit *parent = parents->item;
1287
1288                strbuf_addf(&buffer, "parent %s\n",
1289                            sha1_to_hex(parent->object.sha1));
1290                free(parents);
1291                parents = next;
1292        }
1293
1294        /* Person/date information */
1295        if (!author)
1296                author = git_author_info(IDENT_STRICT);
1297        strbuf_addf(&buffer, "author %s\n", author);
1298        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1299        if (!encoding_is_utf8)
1300                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1301
1302        while (extra) {
1303                add_extra_header(&buffer, extra);
1304                extra = extra->next;
1305        }
1306        strbuf_addch(&buffer, '\n');
1307
1308        /* And add the comment */
1309        strbuf_addbuf(&buffer, msg);
1310
1311        /* And check the encoding */
1312        if (encoding_is_utf8 && !verify_utf8(&buffer))
1313                fprintf(stderr, commit_utf8_warn);
1314
1315        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1316                return -1;
1317
1318        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1319        strbuf_release(&buffer);
1320        return result;
1321}
1322
1323struct commit *get_merge_parent(const char *name)
1324{
1325        struct object *obj;
1326        struct commit *commit;
1327        unsigned char sha1[20];
1328        if (get_sha1(name, sha1))
1329                return NULL;
1330        obj = parse_object(sha1);
1331        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1332        if (commit && !commit->util) {
1333                struct merge_remote_desc *desc;
1334                desc = xmalloc(sizeof(*desc));
1335                desc->obj = obj;
1336                desc->name = strdup(name);
1337                commit->util = desc;
1338        }
1339        return commit;
1340}
1341
1342/*
1343 * Append a commit to the end of the commit_list.
1344 *
1345 * next starts by pointing to the variable that holds the head of an
1346 * empty commit_list, and is updated to point to the "next" field of
1347 * the last item on the list as new commits are appended.
1348 *
1349 * Usage example:
1350 *
1351 *     struct commit_list *list;
1352 *     struct commit_list **next = &list;
1353 *
1354 *     next = commit_list_append(c1, next);
1355 *     next = commit_list_append(c2, next);
1356 *     assert(commit_list_count(list) == 2);
1357 *     return list;
1358 */
1359struct commit_list **commit_list_append(struct commit *commit,
1360                                        struct commit_list **next)
1361{
1362        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1363        new->item = commit;
1364        *next = new;
1365        new->next = NULL;
1366        return &new->next;
1367}
1368
1369void print_commit_list(struct commit_list *list,
1370                       const char *format_cur,
1371                       const char *format_last)
1372{
1373        for ( ; list; list = list->next) {
1374                const char *format = list->next ? format_cur : format_last;
1375                printf(format, sha1_to_hex(list->item->object.sha1));
1376        }
1377}