Andrew's git / gitweb.git / commit.c
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commit.con commit t/lib-t6000: style fixes (50e5a25)
   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "pkt-line.h"
   5#include "utf8.h"
   6#include "diff.h"
   7#include "revision.h"
   8#include "notes.h"
   9#include "gpg-interface.h"
  10#include "mergesort.h"
  11#include "commit-slab.h"
  12#include "prio-queue.h"
  13
  14static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  15
  16int save_commit_buffer = 1;
  17
  18const char *commit_type = "commit";
  19static int commit_count;
  20
  21static struct commit *check_commit(struct object *obj,
  22                                   const unsigned char *sha1,
  23                                   int quiet)
  24{
  25        if (obj->type != OBJ_COMMIT) {
  26                if (!quiet)
  27                        error("Object %s is a %s, not a commit",
  28                              sha1_to_hex(sha1), typename(obj->type));
  29                return NULL;
  30        }
  31        return (struct commit *) obj;
  32}
  33
  34struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  35                                              int quiet)
  36{
  37        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  38
  39        if (!obj)
  40                return NULL;
  41        return check_commit(obj, sha1, quiet);
  42}
  43
  44struct commit *lookup_commit_reference(const unsigned char *sha1)
  45{
  46        return lookup_commit_reference_gently(sha1, 0);
  47}
  48
  49struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  50{
  51        struct commit *c = lookup_commit_reference(sha1);
  52        if (!c)
  53                die(_("could not parse %s"), ref_name);
  54        if (hashcmp(sha1, c->object.sha1)) {
  55                warning(_("%s %s is not a commit!"),
  56                        ref_name, sha1_to_hex(sha1));
  57        }
  58        return c;
  59}
  60
  61struct commit *lookup_commit(const unsigned char *sha1)
  62{
  63        struct object *obj = lookup_object(sha1);
  64        if (!obj) {
  65                struct commit *c = alloc_commit_node();
  66                c->index = commit_count++;
  67                return create_object(sha1, OBJ_COMMIT, c);
  68        }
  69        if (!obj->type)
  70                obj->type = OBJ_COMMIT;
  71        return check_commit(obj, sha1, 0);
  72}
  73
  74struct commit *lookup_commit_reference_by_name(const char *name)
  75{
  76        unsigned char sha1[20];
  77        struct commit *commit;
  78
  79        if (get_sha1_committish(name, sha1))
  80                return NULL;
  81        commit = lookup_commit_reference(sha1);
  82        if (!commit || parse_commit(commit))
  83                return NULL;
  84        return commit;
  85}
  86
  87static unsigned long parse_commit_date(const char *buf, const char *tail)
  88{
  89        const char *dateptr;
  90
  91        if (buf + 6 >= tail)
  92                return 0;
  93        if (memcmp(buf, "author", 6))
  94                return 0;
  95        while (buf < tail && *buf++ != '\n')
  96                /* nada */;
  97        if (buf + 9 >= tail)
  98                return 0;
  99        if (memcmp(buf, "committer", 9))
 100                return 0;
 101        while (buf < tail && *buf++ != '>')
 102                /* nada */;
 103        if (buf >= tail)
 104                return 0;
 105        dateptr = buf;
 106        while (buf < tail && *buf++ != '\n')
 107                /* nada */;
 108        if (buf >= tail)
 109                return 0;
 110        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 111        return strtoul(dateptr, NULL, 10);
 112}
 113
 114static struct commit_graft **commit_graft;
 115static int commit_graft_alloc, commit_graft_nr;
 116
 117static int commit_graft_pos(const unsigned char *sha1)
 118{
 119        int lo, hi;
 120        lo = 0;
 121        hi = commit_graft_nr;
 122        while (lo < hi) {
 123                int mi = (lo + hi) / 2;
 124                struct commit_graft *graft = commit_graft[mi];
 125                int cmp = hashcmp(sha1, graft->sha1);
 126                if (!cmp)
 127                        return mi;
 128                if (cmp < 0)
 129                        hi = mi;
 130                else
 131                        lo = mi + 1;
 132        }
 133        return -lo - 1;
 134}
 135
 136int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 137{
 138        int pos = commit_graft_pos(graft->sha1);
 139
 140        if (0 <= pos) {
 141                if (ignore_dups)
 142                        free(graft);
 143                else {
 144                        free(commit_graft[pos]);
 145                        commit_graft[pos] = graft;
 146                }
 147                return 1;
 148        }
 149        pos = -pos - 1;
 150        if (commit_graft_alloc <= ++commit_graft_nr) {
 151                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 152                commit_graft = xrealloc(commit_graft,
 153                                        sizeof(*commit_graft) *
 154                                        commit_graft_alloc);
 155        }
 156        if (pos < commit_graft_nr)
 157                memmove(commit_graft + pos + 1,
 158                        commit_graft + pos,
 159                        (commit_graft_nr - pos - 1) *
 160                        sizeof(*commit_graft));
 161        commit_graft[pos] = graft;
 162        return 0;
 163}
 164
 165struct commit_graft *read_graft_line(char *buf, int len)
 166{
 167        /* The format is just "Commit Parent1 Parent2 ...\n" */
 168        int i;
 169        struct commit_graft *graft = NULL;
 170
 171        while (len && isspace(buf[len-1]))
 172                buf[--len] = '\0';
 173        if (buf[0] == '#' || buf[0] == '\0')
 174                return NULL;
 175        if ((len + 1) % 41)
 176                goto bad_graft_data;
 177        i = (len + 1) / 41 - 1;
 178        graft = xmalloc(sizeof(*graft) + 20 * i);
 179        graft->nr_parent = i;
 180        if (get_sha1_hex(buf, graft->sha1))
 181                goto bad_graft_data;
 182        for (i = 40; i < len; i += 41) {
 183                if (buf[i] != ' ')
 184                        goto bad_graft_data;
 185                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 186                        goto bad_graft_data;
 187        }
 188        return graft;
 189
 190bad_graft_data:
 191        error("bad graft data: %s", buf);
 192        free(graft);
 193        return NULL;
 194}
 195
 196static int read_graft_file(const char *graft_file)
 197{
 198        FILE *fp = fopen(graft_file, "r");
 199        char buf[1024];
 200        if (!fp)
 201                return -1;
 202        while (fgets(buf, sizeof(buf), fp)) {
 203                /* The format is just "Commit Parent1 Parent2 ...\n" */
 204                int len = strlen(buf);
 205                struct commit_graft *graft = read_graft_line(buf, len);
 206                if (!graft)
 207                        continue;
 208                if (register_commit_graft(graft, 1))
 209                        error("duplicate graft data: %s", buf);
 210        }
 211        fclose(fp);
 212        return 0;
 213}
 214
 215static void prepare_commit_graft(void)
 216{
 217        static int commit_graft_prepared;
 218        char *graft_file;
 219
 220        if (commit_graft_prepared)
 221                return;
 222        graft_file = get_graft_file();
 223        read_graft_file(graft_file);
 224        /* make sure shallows are read */
 225        is_repository_shallow();
 226        commit_graft_prepared = 1;
 227}
 228
 229struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 230{
 231        int pos;
 232        prepare_commit_graft();
 233        pos = commit_graft_pos(sha1);
 234        if (pos < 0)
 235                return NULL;
 236        return commit_graft[pos];
 237}
 238
 239int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 240{
 241        int i, ret;
 242        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 243                ret = fn(commit_graft[i], cb_data);
 244        return ret;
 245}
 246
 247int unregister_shallow(const unsigned char *sha1)
 248{
 249        int pos = commit_graft_pos(sha1);
 250        if (pos < 0)
 251                return -1;
 252        if (pos + 1 < commit_graft_nr)
 253                memmove(commit_graft + pos, commit_graft + pos + 1,
 254                                sizeof(struct commit_graft *)
 255                                * (commit_graft_nr - pos - 1));
 256        commit_graft_nr--;
 257        return 0;
 258}
 259
 260int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 261{
 262        const char *tail = buffer;
 263        const char *bufptr = buffer;
 264        unsigned char parent[20];
 265        struct commit_list **pptr;
 266        struct commit_graft *graft;
 267
 268        if (item->object.parsed)
 269                return 0;
 270        item->object.parsed = 1;
 271        tail += size;
 272        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 273                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 274        if (get_sha1_hex(bufptr + 5, parent) < 0)
 275                return error("bad tree pointer in commit %s",
 276                             sha1_to_hex(item->object.sha1));
 277        item->tree = lookup_tree(parent);
 278        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 279        pptr = &item->parents;
 280
 281        graft = lookup_commit_graft(item->object.sha1);
 282        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 283                struct commit *new_parent;
 284
 285                if (tail <= bufptr + 48 ||
 286                    get_sha1_hex(bufptr + 7, parent) ||
 287                    bufptr[47] != '\n')
 288                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 289                bufptr += 48;
 290                /*
 291                 * The clone is shallow if nr_parent < 0, and we must
 292                 * not traverse its real parents even when we unhide them.
 293                 */
 294                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 295                        continue;
 296                new_parent = lookup_commit(parent);
 297                if (new_parent)
 298                        pptr = &commit_list_insert(new_parent, pptr)->next;
 299        }
 300        if (graft) {
 301                int i;
 302                struct commit *new_parent;
 303                for (i = 0; i < graft->nr_parent; i++) {
 304                        new_parent = lookup_commit(graft->parent[i]);
 305                        if (!new_parent)
 306                                continue;
 307                        pptr = &commit_list_insert(new_parent, pptr)->next;
 308                }
 309        }
 310        item->date = parse_commit_date(bufptr, tail);
 311
 312        return 0;
 313}
 314
 315int parse_commit(struct commit *item)
 316{
 317        enum object_type type;
 318        void *buffer;
 319        unsigned long size;
 320        int ret;
 321
 322        if (!item)
 323                return -1;
 324        if (item->object.parsed)
 325                return 0;
 326        buffer = read_sha1_file(item->object.sha1, &type, &size);
 327        if (!buffer)
 328                return error("Could not read %s",
 329                             sha1_to_hex(item->object.sha1));
 330        if (type != OBJ_COMMIT) {
 331                free(buffer);
 332                return error("Object %s not a commit",
 333                             sha1_to_hex(item->object.sha1));
 334        }
 335        ret = parse_commit_buffer(item, buffer, size);
 336        if (save_commit_buffer && !ret) {
 337                item->buffer = buffer;
 338                return 0;
 339        }
 340        free(buffer);
 341        return ret;
 342}
 343
 344int find_commit_subject(const char *commit_buffer, const char **subject)
 345{
 346        const char *eol;
 347        const char *p = commit_buffer;
 348
 349        while (*p && (*p != '\n' || p[1] != '\n'))
 350                p++;
 351        if (*p) {
 352                p += 2;
 353                for (eol = p; *eol && *eol != '\n'; eol++)
 354                        ; /* do nothing */
 355        } else
 356                eol = p;
 357
 358        *subject = p;
 359
 360        return eol - p;
 361}
 362
 363struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 364{
 365        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 366        new_list->item = item;
 367        new_list->next = *list_p;
 368        *list_p = new_list;
 369        return new_list;
 370}
 371
 372unsigned commit_list_count(const struct commit_list *l)
 373{
 374        unsigned c = 0;
 375        for (; l; l = l->next )
 376                c++;
 377        return c;
 378}
 379
 380void free_commit_list(struct commit_list *list)
 381{
 382        while (list) {
 383                struct commit_list *temp = list;
 384                list = temp->next;
 385                free(temp);
 386        }
 387}
 388
 389struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 390{
 391        struct commit_list **pp = list;
 392        struct commit_list *p;
 393        while ((p = *pp) != NULL) {
 394                if (p->item->date < item->date) {
 395                        break;
 396                }
 397                pp = &p->next;
 398        }
 399        return commit_list_insert(item, pp);
 400}
 401
 402static int commit_list_compare_by_date(const void *a, const void *b)
 403{
 404        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 405        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 406        if (a_date < b_date)
 407                return 1;
 408        if (a_date > b_date)
 409                return -1;
 410        return 0;
 411}
 412
 413static void *commit_list_get_next(const void *a)
 414{
 415        return ((const struct commit_list *)a)->next;
 416}
 417
 418static void commit_list_set_next(void *a, void *next)
 419{
 420        ((struct commit_list *)a)->next = next;
 421}
 422
 423void commit_list_sort_by_date(struct commit_list **list)
 424{
 425        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 426                                commit_list_compare_by_date);
 427}
 428
 429struct commit *pop_most_recent_commit(struct commit_list **list,
 430                                      unsigned int mark)
 431{
 432        struct commit *ret = (*list)->item;
 433        struct commit_list *parents = ret->parents;
 434        struct commit_list *old = *list;
 435
 436        *list = (*list)->next;
 437        free(old);
 438
 439        while (parents) {
 440                struct commit *commit = parents->item;
 441                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 442                        commit->object.flags |= mark;
 443                        commit_list_insert_by_date(commit, list);
 444                }
 445                parents = parents->next;
 446        }
 447        return ret;
 448}
 449
 450static void clear_commit_marks_1(struct commit_list **plist,
 451                                 struct commit *commit, unsigned int mark)
 452{
 453        while (commit) {
 454                struct commit_list *parents;
 455
 456                if (!(mark & commit->object.flags))
 457                        return;
 458
 459                commit->object.flags &= ~mark;
 460
 461                parents = commit->parents;
 462                if (!parents)
 463                        return;
 464
 465                while ((parents = parents->next))
 466                        commit_list_insert(parents->item, plist);
 467
 468                commit = commit->parents->item;
 469        }
 470}
 471
 472void clear_commit_marks(struct commit *commit, unsigned int mark)
 473{
 474        struct commit_list *list = NULL;
 475        commit_list_insert(commit, &list);
 476        while (list)
 477                clear_commit_marks_1(&list, pop_commit(&list), mark);
 478}
 479
 480void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 481{
 482        struct object *object;
 483        struct commit *commit;
 484        unsigned int i;
 485
 486        for (i = 0; i < a->nr; i++) {
 487                object = a->objects[i].item;
 488                commit = lookup_commit_reference_gently(object->sha1, 1);
 489                if (commit)
 490                        clear_commit_marks(commit, mark);
 491        }
 492}
 493
 494struct commit *pop_commit(struct commit_list **stack)
 495{
 496        struct commit_list *top = *stack;
 497        struct commit *item = top ? top->item : NULL;
 498
 499        if (top) {
 500                *stack = top->next;
 501                free(top);
 502        }
 503        return item;
 504}
 505
 506/*
 507 * Topological sort support
 508 */
 509
 510/* count number of children that have not been emitted */
 511define_commit_slab(indegree_slab, int);
 512
 513/* record author-date for each commit object */
 514define_commit_slab(author_date_slab, unsigned long);
 515
 516static void record_author_date(struct author_date_slab *author_date,
 517                               struct commit *commit)
 518{
 519        const char *buf, *line_end;
 520        char *buffer = NULL;
 521        struct ident_split ident;
 522        char *date_end;
 523        unsigned long date;
 524
 525        if (!commit->buffer) {
 526                unsigned long size;
 527                enum object_type type;
 528                buffer = read_sha1_file(commit->object.sha1, &type, &size);
 529                if (!buffer)
 530                        return;
 531        }
 532
 533        for (buf = commit->buffer ? commit->buffer : buffer;
 534             buf;
 535             buf = line_end + 1) {
 536                line_end = strchrnul(buf, '\n');
 537                if (prefixcmp(buf, "author ")) {
 538                        if (!line_end[0] || line_end[1] == '\n')
 539                                return; /* end of header */
 540                        continue;
 541                }
 542                if (split_ident_line(&ident,
 543                                     buf + strlen("author "),
 544                                     line_end - (buf + strlen("author "))) ||
 545                    !ident.date_begin || !ident.date_end)
 546                        goto fail_exit; /* malformed "author" line */
 547                break;
 548        }
 549
 550        date = strtoul(ident.date_begin, &date_end, 10);
 551        if (date_end != ident.date_end)
 552                goto fail_exit; /* malformed date */
 553        *(author_date_slab_at(author_date, commit)) = date;
 554
 555fail_exit:
 556        free(buffer);
 557}
 558
 559static int compare_commits_by_author_date(const void *a_, const void *b_,
 560                                          void *cb_data)
 561{
 562        const struct commit *a = a_, *b = b_;
 563        struct author_date_slab *author_date = cb_data;
 564        unsigned long a_date = *(author_date_slab_at(author_date, a));
 565        unsigned long b_date = *(author_date_slab_at(author_date, b));
 566
 567        /* newer commits with larger date first */
 568        if (a_date < b_date)
 569                return 1;
 570        else if (a_date > b_date)
 571                return -1;
 572        return 0;
 573}
 574
 575static int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 576{
 577        const struct commit *a = a_, *b = b_;
 578        /* newer commits with larger date first */
 579        if (a->date < b->date)
 580                return 1;
 581        else if (a->date > b->date)
 582                return -1;
 583        return 0;
 584}
 585
 586/*
 587 * Performs an in-place topological sort on the list supplied.
 588 */
 589void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 590{
 591        struct commit_list *next, *orig = *list;
 592        struct commit_list **pptr;
 593        struct indegree_slab indegree;
 594        struct prio_queue queue;
 595        struct commit *commit;
 596        struct author_date_slab author_date;
 597
 598        if (!orig)
 599                return;
 600        *list = NULL;
 601
 602        init_indegree_slab(&indegree);
 603        memset(&queue, '\0', sizeof(queue));
 604
 605        switch (sort_order) {
 606        default: /* REV_SORT_IN_GRAPH_ORDER */
 607                queue.compare = NULL;
 608                break;
 609        case REV_SORT_BY_COMMIT_DATE:
 610                queue.compare = compare_commits_by_commit_date;
 611                break;
 612        case REV_SORT_BY_AUTHOR_DATE:
 613                init_author_date_slab(&author_date);
 614                queue.compare = compare_commits_by_author_date;
 615                queue.cb_data = &author_date;
 616                break;
 617        }
 618
 619        /* Mark them and clear the indegree */
 620        for (next = orig; next; next = next->next) {
 621                struct commit *commit = next->item;
 622                *(indegree_slab_at(&indegree, commit)) = 1;
 623                /* also record the author dates, if needed */
 624                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 625                        record_author_date(&author_date, commit);
 626        }
 627
 628        /* update the indegree */
 629        for (next = orig; next; next = next->next) {
 630                struct commit_list *parents = next->item->parents;
 631                while (parents) {
 632                        struct commit *parent = parents->item;
 633                        int *pi = indegree_slab_at(&indegree, parent);
 634
 635                        if (*pi)
 636                                (*pi)++;
 637                        parents = parents->next;
 638                }
 639        }
 640
 641        /*
 642         * find the tips
 643         *
 644         * tips are nodes not reachable from any other node in the list
 645         *
 646         * the tips serve as a starting set for the work queue.
 647         */
 648        for (next = orig; next; next = next->next) {
 649                struct commit *commit = next->item;
 650
 651                if (*(indegree_slab_at(&indegree, commit)) == 1)
 652                        prio_queue_put(&queue, commit);
 653        }
 654
 655        /*
 656         * This is unfortunate; the initial tips need to be shown
 657         * in the order given from the revision traversal machinery.
 658         */
 659        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 660                prio_queue_reverse(&queue);
 661
 662        /* We no longer need the commit list */
 663        free_commit_list(orig);
 664
 665        pptr = list;
 666        *list = NULL;
 667        while ((commit = prio_queue_get(&queue)) != NULL) {
 668                struct commit_list *parents;
 669
 670                for (parents = commit->parents; parents ; parents = parents->next) {
 671                        struct commit *parent = parents->item;
 672                        int *pi = indegree_slab_at(&indegree, parent);
 673
 674                        if (!*pi)
 675                                continue;
 676
 677                        /*
 678                         * parents are only enqueued for emission
 679                         * when all their children have been emitted thereby
 680                         * guaranteeing topological order.
 681                         */
 682                        if (--(*pi) == 1)
 683                                prio_queue_put(&queue, parent);
 684                }
 685                /*
 686                 * all children of commit have already been
 687                 * emitted. we can emit it now.
 688                 */
 689                *(indegree_slab_at(&indegree, commit)) = 0;
 690
 691                pptr = &commit_list_insert(commit, pptr)->next;
 692        }
 693
 694        clear_indegree_slab(&indegree);
 695        clear_prio_queue(&queue);
 696        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 697                clear_author_date_slab(&author_date);
 698}
 699
 700/* merge-base stuff */
 701
 702/* bits #0..15 in revision.h */
 703#define PARENT1         (1u<<16)
 704#define PARENT2         (1u<<17)
 705#define STALE           (1u<<18)
 706#define RESULT          (1u<<19)
 707
 708static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 709
 710static struct commit *interesting(struct commit_list *list)
 711{
 712        while (list) {
 713                struct commit *commit = list->item;
 714                list = list->next;
 715                if (commit->object.flags & STALE)
 716                        continue;
 717                return commit;
 718        }
 719        return NULL;
 720}
 721
 722/* all input commits in one and twos[] must have been parsed! */
 723static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 724{
 725        struct commit_list *list = NULL;
 726        struct commit_list *result = NULL;
 727        int i;
 728
 729        one->object.flags |= PARENT1;
 730        commit_list_insert_by_date(one, &list);
 731        if (!n)
 732                return list;
 733        for (i = 0; i < n; i++) {
 734                twos[i]->object.flags |= PARENT2;
 735                commit_list_insert_by_date(twos[i], &list);
 736        }
 737
 738        while (interesting(list)) {
 739                struct commit *commit;
 740                struct commit_list *parents;
 741                struct commit_list *next;
 742                int flags;
 743
 744                commit = list->item;
 745                next = list->next;
 746                free(list);
 747                list = next;
 748
 749                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 750                if (flags == (PARENT1 | PARENT2)) {
 751                        if (!(commit->object.flags & RESULT)) {
 752                                commit->object.flags |= RESULT;
 753                                commit_list_insert_by_date(commit, &result);
 754                        }
 755                        /* Mark parents of a found merge stale */
 756                        flags |= STALE;
 757                }
 758                parents = commit->parents;
 759                while (parents) {
 760                        struct commit *p = parents->item;
 761                        parents = parents->next;
 762                        if ((p->object.flags & flags) == flags)
 763                                continue;
 764                        if (parse_commit(p))
 765                                return NULL;
 766                        p->object.flags |= flags;
 767                        commit_list_insert_by_date(p, &list);
 768                }
 769        }
 770
 771        free_commit_list(list);
 772        return result;
 773}
 774
 775static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 776{
 777        struct commit_list *list = NULL;
 778        struct commit_list *result = NULL;
 779        int i;
 780
 781        for (i = 0; i < n; i++) {
 782                if (one == twos[i])
 783                        /*
 784                         * We do not mark this even with RESULT so we do not
 785                         * have to clean it up.
 786                         */
 787                        return commit_list_insert(one, &result);
 788        }
 789
 790        if (parse_commit(one))
 791                return NULL;
 792        for (i = 0; i < n; i++) {
 793                if (parse_commit(twos[i]))
 794                        return NULL;
 795        }
 796
 797        list = paint_down_to_common(one, n, twos);
 798
 799        while (list) {
 800                struct commit_list *next = list->next;
 801                if (!(list->item->object.flags & STALE))
 802                        commit_list_insert_by_date(list->item, &result);
 803                free(list);
 804                list = next;
 805        }
 806        return result;
 807}
 808
 809struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 810{
 811        struct commit_list *i, *j, *k, *ret = NULL;
 812        struct commit_list **pptr = &ret;
 813
 814        for (i = in; i; i = i->next) {
 815                if (!ret)
 816                        pptr = &commit_list_insert(i->item, pptr)->next;
 817                else {
 818                        struct commit_list *new = NULL, *end = NULL;
 819
 820                        for (j = ret; j; j = j->next) {
 821                                struct commit_list *bases;
 822                                bases = get_merge_bases(i->item, j->item, 1);
 823                                if (!new)
 824                                        new = bases;
 825                                else
 826                                        end->next = bases;
 827                                for (k = bases; k; k = k->next)
 828                                        end = k;
 829                        }
 830                        ret = new;
 831                }
 832        }
 833        return ret;
 834}
 835
 836static int remove_redundant(struct commit **array, int cnt)
 837{
 838        /*
 839         * Some commit in the array may be an ancestor of
 840         * another commit.  Move such commit to the end of
 841         * the array, and return the number of commits that
 842         * are independent from each other.
 843         */
 844        struct commit **work;
 845        unsigned char *redundant;
 846        int *filled_index;
 847        int i, j, filled;
 848
 849        work = xcalloc(cnt, sizeof(*work));
 850        redundant = xcalloc(cnt, 1);
 851        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 852
 853        for (i = 0; i < cnt; i++)
 854                parse_commit(array[i]);
 855        for (i = 0; i < cnt; i++) {
 856                struct commit_list *common;
 857
 858                if (redundant[i])
 859                        continue;
 860                for (j = filled = 0; j < cnt; j++) {
 861                        if (i == j || redundant[j])
 862                                continue;
 863                        filled_index[filled] = j;
 864                        work[filled++] = array[j];
 865                }
 866                common = paint_down_to_common(array[i], filled, work);
 867                if (array[i]->object.flags & PARENT2)
 868                        redundant[i] = 1;
 869                for (j = 0; j < filled; j++)
 870                        if (work[j]->object.flags & PARENT1)
 871                                redundant[filled_index[j]] = 1;
 872                clear_commit_marks(array[i], all_flags);
 873                for (j = 0; j < filled; j++)
 874                        clear_commit_marks(work[j], all_flags);
 875                free_commit_list(common);
 876        }
 877
 878        /* Now collect the result */
 879        memcpy(work, array, sizeof(*array) * cnt);
 880        for (i = filled = 0; i < cnt; i++)
 881                if (!redundant[i])
 882                        array[filled++] = work[i];
 883        for (j = filled, i = 0; i < cnt; i++)
 884                if (redundant[i])
 885                        array[j++] = work[i];
 886        free(work);
 887        free(redundant);
 888        free(filled_index);
 889        return filled;
 890}
 891
 892struct commit_list *get_merge_bases_many(struct commit *one,
 893                                         int n,
 894                                         struct commit **twos,
 895                                         int cleanup)
 896{
 897        struct commit_list *list;
 898        struct commit **rslt;
 899        struct commit_list *result;
 900        int cnt, i;
 901
 902        result = merge_bases_many(one, n, twos);
 903        for (i = 0; i < n; i++) {
 904                if (one == twos[i])
 905                        return result;
 906        }
 907        if (!result || !result->next) {
 908                if (cleanup) {
 909                        clear_commit_marks(one, all_flags);
 910                        for (i = 0; i < n; i++)
 911                                clear_commit_marks(twos[i], all_flags);
 912                }
 913                return result;
 914        }
 915
 916        /* There are more than one */
 917        cnt = 0;
 918        list = result;
 919        while (list) {
 920                list = list->next;
 921                cnt++;
 922        }
 923        rslt = xcalloc(cnt, sizeof(*rslt));
 924        for (list = result, i = 0; list; list = list->next)
 925                rslt[i++] = list->item;
 926        free_commit_list(result);
 927
 928        clear_commit_marks(one, all_flags);
 929        for (i = 0; i < n; i++)
 930                clear_commit_marks(twos[i], all_flags);
 931
 932        cnt = remove_redundant(rslt, cnt);
 933        result = NULL;
 934        for (i = 0; i < cnt; i++)
 935                commit_list_insert_by_date(rslt[i], &result);
 936        free(rslt);
 937        return result;
 938}
 939
 940struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 941                                    int cleanup)
 942{
 943        return get_merge_bases_many(one, 1, &two, cleanup);
 944}
 945
 946/*
 947 * Is "commit" a descendant of one of the elements on the "with_commit" list?
 948 */
 949int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 950{
 951        if (!with_commit)
 952                return 1;
 953        while (with_commit) {
 954                struct commit *other;
 955
 956                other = with_commit->item;
 957                with_commit = with_commit->next;
 958                if (in_merge_bases(other, commit))
 959                        return 1;
 960        }
 961        return 0;
 962}
 963
 964/*
 965 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 966 */
 967int in_merge_bases(struct commit *commit, struct commit *reference)
 968{
 969        struct commit_list *bases;
 970        int ret = 0;
 971
 972        if (parse_commit(commit) || parse_commit(reference))
 973                return ret;
 974
 975        bases = paint_down_to_common(commit, 1, &reference);
 976        if (commit->object.flags & PARENT2)
 977                ret = 1;
 978        clear_commit_marks(commit, all_flags);
 979        clear_commit_marks(reference, all_flags);
 980        free_commit_list(bases);
 981        return ret;
 982}
 983
 984struct commit_list *reduce_heads(struct commit_list *heads)
 985{
 986        struct commit_list *p;
 987        struct commit_list *result = NULL, **tail = &result;
 988        struct commit **array;
 989        int num_head, i;
 990
 991        if (!heads)
 992                return NULL;
 993
 994        /* Uniquify */
 995        for (p = heads; p; p = p->next)
 996                p->item->object.flags &= ~STALE;
 997        for (p = heads, num_head = 0; p; p = p->next) {
 998                if (p->item->object.flags & STALE)
 999                        continue;
1000                p->item->object.flags |= STALE;
1001                num_head++;
1002        }
1003        array = xcalloc(sizeof(*array), num_head);
1004        for (p = heads, i = 0; p; p = p->next) {
1005                if (p->item->object.flags & STALE) {
1006                        array[i++] = p->item;
1007                        p->item->object.flags &= ~STALE;
1008                }
1009        }
1010        num_head = remove_redundant(array, num_head);
1011        for (i = 0; i < num_head; i++)
1012                tail = &commit_list_insert(array[i], tail)->next;
1013        return result;
1014}
1015
1016static const char gpg_sig_header[] = "gpgsig";
1017static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1018
1019static int do_sign_commit(struct strbuf *buf, const char *keyid)
1020{
1021        struct strbuf sig = STRBUF_INIT;
1022        int inspos, copypos;
1023
1024        /* find the end of the header */
1025        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1026
1027        if (!keyid || !*keyid)
1028                keyid = get_signing_key();
1029        if (sign_buffer(buf, &sig, keyid)) {
1030                strbuf_release(&sig);
1031                return -1;
1032        }
1033
1034        for (copypos = 0; sig.buf[copypos]; ) {
1035                const char *bol = sig.buf + copypos;
1036                const char *eol = strchrnul(bol, '\n');
1037                int len = (eol - bol) + !!*eol;
1038
1039                if (!copypos) {
1040                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1041                        inspos += gpg_sig_header_len;
1042                }
1043                strbuf_insert(buf, inspos++, " ", 1);
1044                strbuf_insert(buf, inspos, bol, len);
1045                inspos += len;
1046                copypos += len;
1047        }
1048        strbuf_release(&sig);
1049        return 0;
1050}
1051
1052int parse_signed_commit(const unsigned char *sha1,
1053                        struct strbuf *payload, struct strbuf *signature)
1054{
1055        unsigned long size;
1056        enum object_type type;
1057        char *buffer = read_sha1_file(sha1, &type, &size);
1058        int in_signature, saw_signature = -1;
1059        char *line, *tail;
1060
1061        if (!buffer || type != OBJ_COMMIT)
1062                goto cleanup;
1063
1064        line = buffer;
1065        tail = buffer + size;
1066        in_signature = 0;
1067        saw_signature = 0;
1068        while (line < tail) {
1069                const char *sig = NULL;
1070                char *next = memchr(line, '\n', tail - line);
1071
1072                next = next ? next + 1 : tail;
1073                if (in_signature && line[0] == ' ')
1074                        sig = line + 1;
1075                else if (!prefixcmp(line, gpg_sig_header) &&
1076                         line[gpg_sig_header_len] == ' ')
1077                        sig = line + gpg_sig_header_len + 1;
1078                if (sig) {
1079                        strbuf_add(signature, sig, next - sig);
1080                        saw_signature = 1;
1081                        in_signature = 1;
1082                } else {
1083                        if (*line == '\n')
1084                                /* dump the whole remainder of the buffer */
1085                                next = tail;
1086                        strbuf_add(payload, line, next - line);
1087                        in_signature = 0;
1088                }
1089                line = next;
1090        }
1091 cleanup:
1092        free(buffer);
1093        return saw_signature;
1094}
1095
1096static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1097{
1098        struct merge_remote_desc *desc;
1099        struct commit_extra_header *mergetag;
1100        char *buf;
1101        unsigned long size, len;
1102        enum object_type type;
1103
1104        desc = merge_remote_util(parent);
1105        if (!desc || !desc->obj)
1106                return;
1107        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1108        if (!buf || type != OBJ_TAG)
1109                goto free_return;
1110        len = parse_signature(buf, size);
1111        if (size == len)
1112                goto free_return;
1113        /*
1114         * We could verify this signature and either omit the tag when
1115         * it does not validate, but the integrator may not have the
1116         * public key of the signer of the tag he is merging, while a
1117         * later auditor may have it while auditing, so let's not run
1118         * verify-signed-buffer here for now...
1119         *
1120         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1121         *      warn("warning: signed tag unverified.");
1122         */
1123        mergetag = xcalloc(1, sizeof(*mergetag));
1124        mergetag->key = xstrdup("mergetag");
1125        mergetag->value = buf;
1126        mergetag->len = size;
1127
1128        **tail = mergetag;
1129        *tail = &mergetag->next;
1130        return;
1131
1132free_return:
1133        free(buf);
1134}
1135
1136void append_merge_tag_headers(struct commit_list *parents,
1137                              struct commit_extra_header ***tail)
1138{
1139        while (parents) {
1140                struct commit *parent = parents->item;
1141                handle_signed_tag(parent, tail);
1142                parents = parents->next;
1143        }
1144}
1145
1146static void add_extra_header(struct strbuf *buffer,
1147                             struct commit_extra_header *extra)
1148{
1149        strbuf_addstr(buffer, extra->key);
1150        if (extra->len)
1151                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1152        else
1153                strbuf_addch(buffer, '\n');
1154}
1155
1156struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1157                                                      const char **exclude)
1158{
1159        struct commit_extra_header *extra = NULL;
1160        unsigned long size;
1161        enum object_type type;
1162        char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1163        if (buffer && type == OBJ_COMMIT)
1164                extra = read_commit_extra_header_lines(buffer, size, exclude);
1165        free(buffer);
1166        return extra;
1167}
1168
1169static inline int standard_header_field(const char *field, size_t len)
1170{
1171        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1172                (len == 6 && !memcmp(field, "parent ", 7)) ||
1173                (len == 6 && !memcmp(field, "author ", 7)) ||
1174                (len == 9 && !memcmp(field, "committer ", 10)) ||
1175                (len == 8 && !memcmp(field, "encoding ", 9)));
1176}
1177
1178static int excluded_header_field(const char *field, size_t len, const char **exclude)
1179{
1180        if (!exclude)
1181                return 0;
1182
1183        while (*exclude) {
1184                size_t xlen = strlen(*exclude);
1185                if (len == xlen &&
1186                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1187                        return 1;
1188                exclude++;
1189        }
1190        return 0;
1191}
1192
1193static struct commit_extra_header *read_commit_extra_header_lines(
1194        const char *buffer, size_t size,
1195        const char **exclude)
1196{
1197        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1198        const char *line, *next, *eof, *eob;
1199        struct strbuf buf = STRBUF_INIT;
1200
1201        for (line = buffer, eob = line + size;
1202             line < eob && *line != '\n';
1203             line = next) {
1204                next = memchr(line, '\n', eob - line);
1205                next = next ? next + 1 : eob;
1206                if (*line == ' ') {
1207                        /* continuation */
1208                        if (it)
1209                                strbuf_add(&buf, line + 1, next - (line + 1));
1210                        continue;
1211                }
1212                if (it)
1213                        it->value = strbuf_detach(&buf, &it->len);
1214                strbuf_reset(&buf);
1215                it = NULL;
1216
1217                eof = strchr(line, ' ');
1218                if (next <= eof)
1219                        eof = next;
1220
1221                if (standard_header_field(line, eof - line) ||
1222                    excluded_header_field(line, eof - line, exclude))
1223                        continue;
1224
1225                it = xcalloc(1, sizeof(*it));
1226                it->key = xmemdupz(line, eof-line);
1227                *tail = it;
1228                tail = &it->next;
1229                if (eof + 1 < next)
1230                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1231        }
1232        if (it)
1233                it->value = strbuf_detach(&buf, &it->len);
1234        return extra;
1235}
1236
1237void free_commit_extra_headers(struct commit_extra_header *extra)
1238{
1239        while (extra) {
1240                struct commit_extra_header *next = extra->next;
1241                free(extra->key);
1242                free(extra->value);
1243                free(extra);
1244                extra = next;
1245        }
1246}
1247
1248int commit_tree(const struct strbuf *msg, unsigned char *tree,
1249                struct commit_list *parents, unsigned char *ret,
1250                const char *author, const char *sign_commit)
1251{
1252        struct commit_extra_header *extra = NULL, **tail = &extra;
1253        int result;
1254
1255        append_merge_tag_headers(parents, &tail);
1256        result = commit_tree_extended(msg, tree, parents, ret,
1257                                      author, sign_commit, extra);
1258        free_commit_extra_headers(extra);
1259        return result;
1260}
1261
1262static int find_invalid_utf8(const char *buf, int len)
1263{
1264        int offset = 0;
1265
1266        while (len) {
1267                unsigned char c = *buf++;
1268                int bytes, bad_offset;
1269
1270                len--;
1271                offset++;
1272
1273                /* Simple US-ASCII? No worries. */
1274                if (c < 0x80)
1275                        continue;
1276
1277                bad_offset = offset-1;
1278
1279                /*
1280                 * Count how many more high bits set: that's how
1281                 * many more bytes this sequence should have.
1282                 */
1283                bytes = 0;
1284                while (c & 0x40) {
1285                        c <<= 1;
1286                        bytes++;
1287                }
1288
1289                /* Must be between 1 and 5 more bytes */
1290                if (bytes < 1 || bytes > 5)
1291                        return bad_offset;
1292
1293                /* Do we *have* that many bytes? */
1294                if (len < bytes)
1295                        return bad_offset;
1296
1297                offset += bytes;
1298                len -= bytes;
1299
1300                /* And verify that they are good continuation bytes */
1301                do {
1302                        if ((*buf++ & 0xc0) != 0x80)
1303                                return bad_offset;
1304                } while (--bytes);
1305
1306                /* We could/should check the value and length here too */
1307        }
1308        return -1;
1309}
1310
1311/*
1312 * This verifies that the buffer is in proper utf8 format.
1313 *
1314 * If it isn't, it assumes any non-utf8 characters are Latin1,
1315 * and does the conversion.
1316 *
1317 * Fixme: we should probably also disallow overlong forms and
1318 * invalid characters. But we don't do that currently.
1319 */
1320static int verify_utf8(struct strbuf *buf)
1321{
1322        int ok = 1;
1323        long pos = 0;
1324
1325        for (;;) {
1326                int bad;
1327                unsigned char c;
1328                unsigned char replace[2];
1329
1330                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1331                if (bad < 0)
1332                        return ok;
1333                pos += bad;
1334                ok = 0;
1335                c = buf->buf[pos];
1336                strbuf_remove(buf, pos, 1);
1337
1338                /* We know 'c' must be in the range 128-255 */
1339                replace[0] = 0xc0 + (c >> 6);
1340                replace[1] = 0x80 + (c & 0x3f);
1341                strbuf_insert(buf, pos, replace, 2);
1342                pos += 2;
1343        }
1344}
1345
1346static const char commit_utf8_warn[] =
1347"Warning: commit message did not conform to UTF-8.\n"
1348"You may want to amend it after fixing the message, or set the config\n"
1349"variable i18n.commitencoding to the encoding your project uses.\n";
1350
1351int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1352                         struct commit_list *parents, unsigned char *ret,
1353                         const char *author, const char *sign_commit,
1354                         struct commit_extra_header *extra)
1355{
1356        int result;
1357        int encoding_is_utf8;
1358        struct strbuf buffer;
1359
1360        assert_sha1_type(tree, OBJ_TREE);
1361
1362        if (memchr(msg->buf, '\0', msg->len))
1363                return error("a NUL byte in commit log message not allowed.");
1364
1365        /* Not having i18n.commitencoding is the same as having utf-8 */
1366        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1367
1368        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1369        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1370
1371        /*
1372         * NOTE! This ordering means that the same exact tree merged with a
1373         * different order of parents will be a _different_ changeset even
1374         * if everything else stays the same.
1375         */
1376        while (parents) {
1377                struct commit_list *next = parents->next;
1378                struct commit *parent = parents->item;
1379
1380                strbuf_addf(&buffer, "parent %s\n",
1381                            sha1_to_hex(parent->object.sha1));
1382                free(parents);
1383                parents = next;
1384        }
1385
1386        /* Person/date information */
1387        if (!author)
1388                author = git_author_info(IDENT_STRICT);
1389        strbuf_addf(&buffer, "author %s\n", author);
1390        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1391        if (!encoding_is_utf8)
1392                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1393
1394        while (extra) {
1395                add_extra_header(&buffer, extra);
1396                extra = extra->next;
1397        }
1398        strbuf_addch(&buffer, '\n');
1399
1400        /* And add the comment */
1401        strbuf_addbuf(&buffer, msg);
1402
1403        /* And check the encoding */
1404        if (encoding_is_utf8 && !verify_utf8(&buffer))
1405                fprintf(stderr, commit_utf8_warn);
1406
1407        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1408                return -1;
1409
1410        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1411        strbuf_release(&buffer);
1412        return result;
1413}
1414
1415struct commit *get_merge_parent(const char *name)
1416{
1417        struct object *obj;
1418        struct commit *commit;
1419        unsigned char sha1[20];
1420        if (get_sha1(name, sha1))
1421                return NULL;
1422        obj = parse_object(sha1);
1423        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1424        if (commit && !commit->util) {
1425                struct merge_remote_desc *desc;
1426                desc = xmalloc(sizeof(*desc));
1427                desc->obj = obj;
1428                desc->name = strdup(name);
1429                commit->util = desc;
1430        }
1431        return commit;
1432}
1433
1434/*
1435 * Append a commit to the end of the commit_list.
1436 *
1437 * next starts by pointing to the variable that holds the head of an
1438 * empty commit_list, and is updated to point to the "next" field of
1439 * the last item on the list as new commits are appended.
1440 *
1441 * Usage example:
1442 *
1443 *     struct commit_list *list;
1444 *     struct commit_list **next = &list;
1445 *
1446 *     next = commit_list_append(c1, next);
1447 *     next = commit_list_append(c2, next);
1448 *     assert(commit_list_count(list) == 2);
1449 *     return list;
1450 */
1451struct commit_list **commit_list_append(struct commit *commit,
1452                                        struct commit_list **next)
1453{
1454        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1455        new->item = commit;
1456        *next = new;
1457        new->next = NULL;
1458        return &new->next;
1459}
1460
1461void print_commit_list(struct commit_list *list,
1462                       const char *format_cur,
1463                       const char *format_last)
1464{
1465        for ( ; list; list = list->next) {
1466                const char *format = list->next ? format_cur : format_last;
1467                printf(format, sha1_to_hex(list->item->object.sha1));
1468        }
1469}